@import url("https://cdn.jsdelivr.net/npm/bootstrap@5.3.3/dist/css/bootstrap.min.css");

@import url("https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800;900&family=Orbitron:wght@700;800;900&family=Sora:wght@600;700;800&display=swap");

/* ==========================================================
   CS4GATE — Global Stylesheet
   - Preserves original navy navbar + gradient sidebar
   - Adds: dark/light theme, filter chips, bookmarks,
           skeletons, footer, scroll-top, quiz UI, etc.
   ========================================================== */

/* ============================
   THEME TOKENS (Teal + Orange)
   ============================ */
:root {
  --primary: hsl(180, 70%, 40%);       /* teal */
  --primary-2: hsl(190, 75%, 45%);     /* aqua */
  --accent: hsl(268, 58%, 38%);        /* dark purple accent */
  --nav: hsl(210, 40%, 15%);           /* deep navy */
  --nav-2: hsl(210, 35%, 20%);
  --sidebar-1: hsl(210, 40%, 15%);
  --sidebar-2: hsl(210, 45%, 25%);
  --bg: hsl(210, 60%, 98%);            /* soft neutral */
  --bg-elev: hsl(0, 0%, 100%);
  --bg-soft: hsl(210, 55%, 96%);
  --bg-subtle: hsl(210, 55%, 96%);
  --text: hsl(210, 20%, 15%);          /* dark gray */
  --text-muted: hsl(210, 10%, 45%);    /* muted gray */
  --border: hsla(210, 15%, 65%, 0.35);
  --success: hsl(145, 65%, 45%);
  --warning: hsl(35, 85%, 50%);
  --danger: hsl(0, 75%, 55%);
  --info: hsl(200, 85%, 55%);
  --input-bg: hsl(0, 0%, 100%);
  --input-text: hsl(210, 20%, 10%);
  --nav-text: hsl(0, 0%, 100%);
  --hero-text: hsl(0, 0%, 100%);
  --hero-subtext: hsla(0, 0%, 100%, 0.86);
  --brand-cs: hsl(190, 95%, 78%);
  --brand-gate: hsl(0, 0%, 100%);
  --hero-stat-bg: hsla(210, 34%, 22%, 0.92);
  --hero-stat-border: hsla(0, 0%, 100%, 0.22);
  --overlay-bg: hsl(0, 0%, 100%);
  --overlay-soft: hsl(210, 58%, 96%);
  --scroll-track: hsl(210, 30%, 93%);
  --scroll-track-border: hsl(210, 20%, 78%);
  --scroll-thumb: hsl(195, 32%, 58%);
  --scroll-thumb-border: hsl(195, 35%, 48%);
  --scroll-thumb-hover: hsl(190, 52%, 46%);
  --scroll-thumb-solid: hsl(190, 52%, 46%);
  --type-mcq: hsl(214, 84%, 55%);
  --type-msq: hsl(272, 70%, 57%);
  --type-nat: hsl(43, 96%, 67%);
  --type-nat-text: hsl(27, 44%, 20%);
  --ai-assistant-top: 64px;
  --ai-assistant-bottom-gap: 16px;
  --hero-gradient: radial-gradient(1200px 420px at 10% -20%, hsla(180,70%,40%,0.35), transparent 60%),
                   radial-gradient(1000px 380px at 90% 0%, hsla(30,90%,55%,0.28), transparent 58%),
                   linear-gradient(140deg, hsl(210,40%,15%) 0%, hsl(210,35%,20%) 45%, hsl(210,40%,15%) 100%);
  --premium-gradient: hsl(268, 58%, 38%);
  --focus-ring: hsla(268, 58%, 38%, 0.3);
  --shadow-sm: rgba(0, 0, 0, 0.16) 0px 1px 4px;
  --shadow-md: rgba(0, 0, 0, 0.24) 0px 3px 8px;
  --shadow-lg: rgba(60, 64, 67, 0.3) 0px 1px 2px 0px,
               rgba(60, 64, 67, 0.15) 0px 2px 6px 2px;
  --card-radius: 8px;
  --card-border: 1px solid var(--border);
  --card-bg: linear-gradient(
    145deg,
    color-mix(in srgb, var(--bg-elev) 92%, var(--bg-soft)),
    var(--bg-elev)
  );
  --card-shadow: rgba(50, 50, 93, 0.25) 0px 2px 5px -1px,
                 rgba(0, 0, 0, 0.3) 0px 1px 3px -1px;
  --card-shadow-hover: rgba(0, 0, 0, 0.24) 0px 3px 8px;
  --grid-gap-lg: 18px;
  --grid-gap-md: 14px;
  --grid-gap-sm: 10px;
  --q-card-h-desktop: 220px;
  --q-card-h-tablet: 200px;
  --q-card-h-mobile: 176px;
  --similar-card-h-desktop: 190px;
  --similar-card-h-tablet: 174px;
  --similar-card-h-mobile: 156px;
  --course-card-h-desktop: 148px;
  --course-card-h-tablet: 136px;
  --course-card-h-mobile: 124px;
  --btn-primary-bg: var(--premium-gradient);
  --btn-primary-text: hsl(0, 0%, 100%);
  --btn-surface-bg: color-mix(in srgb, var(--bg-elev) 88%, var(--premium-gradient) 12%);
  --btn-surface-bg-hover: color-mix(in srgb, var(--bg-elev) 72%, var(--premium-gradient) 28%);
  --btn-surface-text: color-mix(in srgb, var(--text) 86%, var(--premium-gradient) 14%);
  --btn-surface-border: color-mix(in srgb, var(--border) 72%, var(--premium-gradient) 28%);
  --radius: 8px;
  --transition: 0.35s cubic-bezier(0.22, 1, 0.36, 1);
}

[data-theme="dark"] {
  --primary: hsl(180, 70%, 55%);
  --primary-2: hsl(190, 75%, 60%);
  --accent: hsl(268, 76%, 66%);
  --nav: hsl(210, 40%, 8%);
  --nav-2: hsl(210, 35%, 15%);
  --sidebar-1: hsl(210, 40%, 8%);
  --sidebar-2: hsl(210, 45%, 20%);
  --bg: hsl(210, 40%, 8%);
  --bg-elev: hsl(210, 28%, 16%);
  --bg-soft: hsl(210, 26%, 13%);
  --bg-subtle: hsl(210, 40%, 15%);
  --text: hsl(210, 60%, 95%);
  --text-muted: hsl(210, 20%, 70%);
  --border: hsla(210, 15%, 65%, 0.36);
  --success: hsl(145, 65%, 55%);
  --warning: hsl(35, 85%, 55%);
  --danger: hsl(0, 75%, 65%);
  --info: hsl(200, 85%, 75%);
  --input-bg: hsl(210, 40%, 15%);
  --input-text: hsl(210, 60%, 95%);
  --nav-text: hsl(210, 70%, 97%);
  --hero-text: hsl(210, 70%, 97%);
  --hero-subtext: hsl(210, 35%, 84%);
  --brand-cs: hsl(188, 96%, 74%);
  --brand-gate: hsl(210, 70%, 97%);
  --hero-stat-bg: hsl(210, 30%, 20%);
  --hero-stat-border: hsla(210, 40%, 70%, 0.28);
  --overlay-bg: hsl(210, 26%, 14%);
  --overlay-soft: hsl(210, 26%, 18%);
  --scroll-track: hsl(210, 22%, 16%);
  --scroll-track-border: hsl(210, 18%, 26%);
  --scroll-thumb: hsl(194, 55%, 46%);
  --scroll-thumb-border: hsl(194, 55%, 38%);
  --scroll-thumb-hover: hsl(190, 72%, 58%);
  --scroll-thumb-solid: hsl(190, 72%, 58%);
  --type-mcq: hsl(204, 84%, 62%);
  --type-msq: hsl(276, 76%, 69%);
  --type-nat: hsl(45, 95%, 63%);
  --type-nat-text: hsl(220, 27%, 12%);
  --ai-assistant-top: 64px;
  --ai-assistant-bottom-gap: 16px;
  --btn-primary-bg: var(--premium-gradient);
  --btn-primary-text: hsl(0, 0%, 100%);
  --btn-surface-bg: color-mix(in srgb, var(--bg-elev) 80%, var(--premium-gradient) 20%);
  --btn-surface-bg-hover: color-mix(in srgb, var(--bg-elev) 64%, var(--premium-gradient) 36%);
  --btn-surface-text: color-mix(in srgb, var(--text) 90%, var(--premium-gradient) 10%);
  --btn-surface-border: color-mix(in srgb, var(--border) 70%, var(--premium-gradient) 30%);
  --hero-gradient: radial-gradient(1200px 420px at 12% -10%, hsla(180,70%,55%,0.28), transparent 60%),
                   radial-gradient(900px 320px at 90% 0%, hsla(30,90%,65%,0.25), transparent 58%),
                   linear-gradient(140deg, hsl(210,40%,8%) 0%, hsl(210,40%,15%) 50%, hsl(210,40%,8%) 100%);
  --premium-gradient: hsl(268, 76%, 66%);
  --focus-ring: hsla(268, 76%, 66%, 0.32);
  --shadow-sm: rgba(0, 0, 0, 0.16) 0px 1px 4px;
  --shadow-md: rgba(0, 0, 0, 0.24) 0px 3px 8px;
  --shadow-lg: rgba(60, 64, 67, 0.3) 0px 1px 2px 0px,rgba(60, 64, 67, 0.15) 0px 2px 6px 2px;
}

/* ============================
   RESET & GLOBAL
   ============================ */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "Inter", "Segoe UI", system-ui, -apple-system, sans-serif;
  scrollbar-width: thin;
  scrollbar-color: var(--scroll-thumb-solid) var(--scroll-track);
}

h1, h2, h3, h4, h5, h6,
.logo, .auth-logo,
.section-heading,
.panel-title h2 {
  font-family: "Sora", "Inter", "Segoe UI", system-ui, -apple-system, sans-serif;
}

/* ============================
   GLOBAL PREMIUM SCROLLBARS
   ============================ */
*::-webkit-scrollbar {
  width: 12px;
  height: 12px;
}

*::-webkit-scrollbar-track {
  background: var(--scroll-track);
  border: 1px solid var(--scroll-track-border);
  box-shadow: inset 0 0 0 1px color-mix(in srgb, var(--scroll-track-border) 45%, transparent);
}

*::-webkit-scrollbar-thumb {
  background: var(--scroll-thumb);
  border: 1px solid var(--scroll-thumb-border);
  box-shadow: inset 0 0 0 1px rgba(255,255,255,0.22);
}

*::-webkit-scrollbar-thumb:hover {
  background: var(--scroll-thumb-hover);
}

*::-webkit-scrollbar-thumb:active {
  background: var(--scroll-thumb-hover);
  box-shadow: inset 0 0 0 1px rgba(255,255,255,0.3), 0 0 0 1px rgba(14,165,233,0.2);
}

*::-webkit-scrollbar-corner {
  background: var(--scroll-track);
}

@keyframes premium-float-in {
  from {
    opacity: 0;
    transform: translateY(10px);
    filter: blur(4px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
    filter: blur(0);
  }
}

body {
  background:
    radial-gradient(1300px 460px at 10% -15%, color-mix(in srgb, var(--primary) 26%, transparent), transparent 60%),
    radial-gradient(1000px 380px at 92% -8%, color-mix(in srgb, var(--accent) 22%, transparent), transparent 60%),
    linear-gradient(180deg, var(--bg-subtle) 0%, var(--bg) 340px),
    var(--bg);
  color: var(--text);
  transition: background var(--transition), color var(--transition);
  min-height: 100vh;
}

[data-theme="dark"] body {
  background:
    radial-gradient(1200px 460px at 6% -16%, rgba(77,168,218,0.26), transparent 58%),
    radial-gradient(960px 360px at 92% -8%, rgba(0,124,199,0.2), transparent 60%),
    linear-gradient(180deg, var(--bg-subtle) 0%, var(--bg) 340px),
    var(--bg);
}

/* Single-source theme tokens are defined in the first :root block above.
   Keep component styling below and avoid duplicate global overrides. */
body::before,
body::after {
  content: none;
  display: none;
}

a { text-decoration: none; color: inherit; }
button { font-family: inherit; cursor: pointer; }

.navbar,
.sidebar,
.right-panel,
.card,
.search-card,
.q-card,
.content-card,
.similar-item,
.course-question-card,
.upgrade-card,
.history-card,
.ad-slot,
.btn,
.chip,
.seo-nav-card,
.panel-item,
.menu-item,
.auth-card,
.app-modal-card,
.profile-card-mini {
  backdrop-filter: none;
  -webkit-backdrop-filter: none;
  transition:
    transform var(--transition),
    box-shadow var(--transition),
    border-color var(--transition),
    background var(--transition),
    color var(--transition),
    filter var(--transition);
}

.question-list .card,
.question-list .search-card,
.similar-list .similar-item,
.course-question-grid .course-question-card {
  animation: premium-float-in 0.5s var(--transition) both;
}

.question-list .card:nth-child(2),
.question-list .search-card:nth-child(2),
.similar-list .similar-item:nth-child(2),
.course-question-grid .course-question-card:nth-child(2) { animation-delay: 0.04s; }

.question-list .card:nth-child(3),
.question-list .search-card:nth-child(3),
.similar-list .similar-item:nth-child(3),
.course-question-grid .course-question-card:nth-child(3) { animation-delay: 0.08s; }

.question-list .card:nth-child(4),
.question-list .search-card:nth-child(4),
.similar-list .similar-item:nth-child(4),
.course-question-grid .course-question-card:nth-child(4) { animation-delay: 0.12s; }

/* ============================
   NAVBAR
   ============================ */
.navbar {
  position: fixed;
  top: 0; left: 0;
  width: 100%;
  height: 60px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 15px;
  background: linear-gradient(90deg, var(--nav), var(--nav-2));
  color: var(--nav-text);
  box-shadow: var(--shadow-md);
  z-index: 1000;
  border-bottom: 1px solid var(--border);
  animation: premium-float-in 0.45s var(--transition) both;
}

.nav-left { display: flex; align-items: center; gap: 12px; }

.hamburger { display: none; cursor: pointer; font-size: 18px; }

.logo {
  font-weight: bold;
  font-size: 1.15rem;
  letter-spacing: 0.5px;
  display: flex;
  align-items: center;
  min-width: 0;
}
.logo a {
  color: var(--nav-text);
  display: inline-flex;
  align-items: center;
  min-width: 0;
}

.brand-logo-link {
  display: inline-flex !important;
  align-items: center;
  line-height: 1;
  max-width: min(46vw, 260px);
}

.brand-wordmark {
  display: inline-flex;
  align-items: center;
  gap: 1px;
  white-space: nowrap;
  font-family: "Orbitron", "Sora", "Inter", "Segoe UI", system-ui, -apple-system, sans-serif;
  font-weight: 800;
  font-size: clamp(1.03rem, 1.1vw + 0.64rem, 1.45rem);
  line-height: 1;
  letter-spacing: 0;
  text-transform: uppercase;
  text-shadow: 0 1px 6px rgba(2, 6, 23, 0.38);
}

.brand-wordmark-cs {
  color: var(--brand-cs);
}

.brand-wordmark-4 {
  color: var(--accent);
}

.brand-wordmark-gate {
  color: var(--brand-gate);
}

.navbar .brand-wordmark {
  font-size: clamp(1rem, 0.95vw + 0.62rem, 1.25rem);
}

.landing-nav .brand-wordmark {
  font-size: clamp(1.02rem, 0.82vw + 0.74rem, 1.18rem);
}

.landing-nav .brand-wordmark-gate {
  color: var(--text);
}

[data-theme="dark"] .landing-nav .brand-wordmark-gate {
  color: var(--text);
}

.auth-brand .brand-wordmark {
  font-size: clamp(1.2rem, 1.6vw + 0.8rem, 1.6rem);
}

.nav-search {
  flex: 1;
  max-width: 480px;
  position: relative;
}

.nav-search input {
  width: 100%;
  padding: 9px 36px 9px 14px;
  font-size: 14px;
  border: 1px solid var(--border);
  outline: none;
  background: var(--input-bg);
  color: var(--input-text);
  transition: all 0.3s ease;
}

.nav-search input::placeholder {
  color: color-mix(in srgb, var(--input-text) 58%, transparent);
  opacity: 1;
}

[data-theme="dark"] .nav-search input {
  background: var(--input-bg);
  color: var(--input-text);
  border-color: var(--border);
}

[data-theme="dark"] .nav-search input::placeholder {
  color: color-mix(in srgb, var(--input-text) 72%, transparent);
}

.nav-search input:focus {
  border-color: var(--primary);
  background: var(--input-bg);
  box-shadow: 0 0 0 3px var(--focus-ring);
}

.search-clear-btn {
  position: absolute;
  right: 8px; top: 50%;
  transform: translateY(-50%);
  width: 24px; height: 24px;
  border: none;
  background: transparent;
  color: var(--text-muted);
  display: none;
  align-items: center;
  justify-content: center;
  }
.search-clear-btn.show { display: flex; }
.search-clear-btn:hover { background: var(--bg-soft); color: var(--danger); }

.nav-right { display: flex; align-items: center; gap: 15px; }
.desktop-icons { display: flex; gap: 15px; }
.nav-right i { cursor: pointer; transition: transform 0.2s, color 0.2s; }
.nav-right i:hover { transform: scale(1.15); color: var(--primary); }

.ai-assistant-nav-btn {
  width: 36px;
  height: 36px;
  border: 1px solid color-mix(in srgb, #ffffff 24%, transparent);
  background: color-mix(in srgb, var(--nav-2) 74%, transparent);
  color: var(--nav-text);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  line-height: 1;
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition), color var(--transition), border-color var(--transition), background var(--transition);
}

.ai-assistant-nav-btn i {
  pointer-events: none;
}

.ai-assistant-nav-btn:hover {
  transform: translateY(-1px);
  border-color: color-mix(in srgb, var(--primary) 72%, #ffffff 12%);
  color: var(--primary);
  background: color-mix(in srgb, var(--nav-2) 45%, var(--primary) 28%);
}

.landing-nav .ai-assistant-nav-btn {
  width: 36px;
  height: 36px;
  flex: 0 0 36px;
  border: 1px solid var(--btn-surface-border);
  background: var(--btn-surface-bg);
  color: var(--btn-surface-text);
  order: 0;
  align-self: center;
}

.landing-nav .ai-assistant-nav-btn:hover {
  color: var(--primary);
  border-color: var(--primary);
  background: var(--btn-surface-bg-hover);
}

.nav-right .mobile-search,
.nav-right .mobile-slider { display: none; }

/* Mobile search-active mode */
.navbar.search-active { background: var(--bg-elev); }
.navbar.search-active .nav-left,
.navbar.search-active .desktop-icons,
.navbar.search-active .mobile-slider { display: none; }
.navbar.search-active .ai-assistant-nav-btn.app-nav { display: none; }
.navbar.search-active .nav-search { display: flex; flex: 1; padding: 0 10px; }
.navbar.search-active .nav-search input {
  background: var(--input-bg); color: var(--input-text); border: 1px solid var(--border); padding: 10px;
}
.navbar.search-active .mobile-search {
  display: block; font-size: 20px; color: var(--primary); margin-left: 10px;
}

/* ============================
   SIDEBAR
   ============================ */
.sidebar {
  position: fixed;
  top: 60px; left: 0;
  width: 300px;
  height: calc(100vh - 60px);
  background: linear-gradient(180deg, var(--sidebar-1), var(--sidebar-2));
  color: #fff;
  display: flex;
  flex-direction: column;
  box-shadow: var(--shadow-md);
  transition: transform 0.3s ease;
  z-index: 980;
}

.sidebar-menu { flex: 1; overflow-y: auto; padding: 12px; }

.menu-item {
  padding: 11px 14px;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-bottom: 1px solid rgba(255,255,255,0.10);
  transition: background 0.25s, transform 0.2s;
  font-size: 0.92rem;
}
.menu-item:hover { background: rgba(255,255,255,0.12); transform: translateX(2px); }
.menu-item.selected {
  background: color-mix(in srgb, var(--accent) 26%, transparent);
  color: color-mix(in srgb, #ffffff 90%, var(--accent) 10%);
  font-weight: 600;
}

.dropdown.active { background: rgba(255,255,255,0.14); }
.dropdown.active > .arrow { transform: rotate(180deg); }
.arrow { transition: transform 0.25s; font-size: 12px; opacity: 0.8; }

.submenu {
  display: none;
  padding-left: 14px;
  border-left: 2px solid rgba(255,255,255,0.2);
  margin: 4px 0 4px 8px;
}
.submenu .menu-item { border-bottom: none; padding: 9px 12px; font-size: 0.88rem; }

.sidebar-footer {
  padding: 14px;
  border-top: 1px solid rgba(255,255,255,0.2);
  display: flex; align-items: center; gap: 10px;
  background: rgba(0,0,0,0.18);
}
.sidebar-footer i { font-size: 22px; color: var(--accent); }

/* ============================
   LAYOUT
   ============================ */
.container {
  margin-top: 60px;
  margin-left: 300px;
  width: calc(100% - 300px);
  padding: 18px 30px 18px 18px;
  transition: margin 0.3s;
  overflow-x: hidden;
}
.content { display: flex; gap: 18px; }
.main { flex: 3; padding: 6px; min-width: 0; }
.right { flex: 1; padding: 18px; background: var(--bg-elev); box-shadow: var(--shadow-sm); align-self: flex-start; }

/* ============================
   HERO SECTION
   ============================ */
.home-hero {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 24px;
  background: var(--hero-gradient);
  color: var(--hero-text);
  padding: 36px;
  box-shadow: var(--shadow-md);
  margin-bottom: 22px;
  border: 1px solid color-mix(in srgb, var(--hero-text) 16%, transparent);
}

.hero-left { flex: 1; }
.hero-left h1 { font-size: 28px; font-weight: 800; margin-bottom: 6px; }
.hero-left p { font-size: 15px; opacity: 1; color: var(--hero-subtext); }

.hero-stats { display: flex; gap: 14px; margin: 20px 0; flex-wrap: wrap; }
.stat-box {
  background: var(--hero-stat-bg);
  backdrop-filter: blur(10px);
  padding: 14px 18px;
  text-align: center;
  min-width: 110px;
  border: 1px solid var(--hero-stat-border);
}
.stat-box h2 { font-size: 22px; margin-bottom: 4px; font-weight: 700; }
.stat-box p { font-size: 12px; opacity: 1; color: var(--hero-subtext); }

.hero-btn {
  background: var(--premium-gradient);
  color: var(--hero-text);
  padding: 11px 22px;
  border: none;
  cursor: pointer;
  font-size: 15px;
  font-weight: 700;
  transition: 0.25s;
}
.hero-btn:hover { transform: translateY(-2px); box-shadow: var(--shadow-md); }

.hero-right img { width: 200px; height: auto; opacity: 0.95; }

/* ============================
   TOOLBAR (filter chips + actions)
   ============================ */
.toolbar {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: center;
  margin-bottom: 16px;
}

.filter-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  flex: 1;
  min-height: 30px;
}
.chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--premium-gradient);
  color: #fff;
  padding: 5px 8px 5px 12px;
  font-size: 12px;
  font-weight: 500;
  animation: pop 0.2s ease;
}
@keyframes pop { from { transform: scale(0.8); opacity: 0; } to { transform: scale(1); opacity: 1; } }
.chip button {
  background: rgba(255,255,255,0.25);
  border: none;
  color: #fff;
  width: 18px; height: 18px;
  font-size: 13px;
  display: flex; align-items: center; justify-content: center;
}
.chip button:hover { background: rgba(255,255,255,0.45); }
.chip-clear-all {
  background: transparent;
  color: var(--danger);
  border: none;
  font-weight: 600;
  font-size: 12px;
  padding: 4px 8px;
  }
.chip-clear-all:hover { background: var(--bg-soft); }

.btn {
  min-height: 40px;
  padding: 0 16px;
  border: 1px solid transparent;
  border-radius: var(--radius);
  font-weight: 700;
  font-size: 13px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  line-height: 1;
  box-shadow: var(--shadow-sm);
  transition: 0.25s;
}
.btn-primary { background: var(--btn-primary-bg); color: var(--btn-primary-text); border-color: transparent; }
.btn-primary:hover { transform: translateY(-1px); box-shadow: var(--shadow-md); filter: saturate(1.06); }
.btn-outline { background: var(--btn-surface-bg); color: var(--btn-surface-text); border-color: var(--btn-surface-border); }
.btn-outline:hover { background: var(--btn-surface-bg-hover); border-color: var(--primary); color: var(--primary); }
.btn-ghost { background: transparent; color: var(--text); border-color: transparent; box-shadow: none; }
.btn-ghost:hover { background: var(--bg-soft); border-color: var(--border); }

.btn:focus-visible,
.landing-theme-toggle:focus-visible,
.landing-menu-toggle:focus-visible,
.ai-assistant-nav-btn:focus-visible,
.portal-search button:focus-visible {
  outline: 2px solid var(--focus-ring);
  outline-offset: 2px;
}

/* ============================
   QUESTION GRID & CARDS
   ============================ */
.section-heading {
  font-size: 1.15rem;
  font-weight: 700;
  margin: 6px 0 12px;
  color: var(--text);
}

.question-list {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: var(--grid-gap-lg);
  align-items: stretch;
}

.question-list > .card,
.question-list > .search-card {
  width: 100%;
  max-width: none;
  justify-self: stretch;
}

.question-list > .card:only-child,
.question-list > .search-card:only-child {
  max-width: 360px;
  justify-self: start;
}

.card,
.search-card {
  background: var(--card-bg);
  padding: 16px;
  cursor: pointer;
  box-shadow: var(--card-shadow);
  border: var(--card-border);
  transition: transform 0.22s ease, box-shadow 0.22s ease, border-color 0.22s ease;
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 10px;
  height: var(--q-card-h-desktop);
  min-height: var(--q-card-h-desktop);
  overflow: hidden;
  isolation: isolate;
}
.card::before,
.search-card::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 3px;
  background: var(--premium-gradient);
  opacity: 0;
  transition: opacity 0.25s ease;
}
.card:hover,
.search-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--card-shadow-hover);
  border-color: var(--primary);
}
.card:hover::before,
.search-card:hover::before {
  opacity: 1;
}

.card-meta,
.search-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  font-size: 11px;
  color: var(--text-muted);
  align-items: center;
}

.card-text {
  font-size: 0.9rem;
  color: var(--text);
  flex: 1;
  display: -webkit-box;
  -webkit-line-clamp: 4;
  -webkit-box-orient: vertical;
  overflow: hidden;
  line-height: 1.45;
}

.card-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-top: 1px solid var(--border);
  padding-top: 8px;
  font-size: 11px;
  color: var(--text-muted);
  gap: 8px;
}

.card-footer > span:first-child {
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.card-meta,
.search-meta,
.card-footer,
.section-badge,
.q-badge,
.search-group-title,
.similar-item span,
.course-question-card span,
.portal-ad-grid .ad-slot p,
.ad-slot p {
  color: color-mix(in srgb, var(--text) 72%, var(--text-muted) 28%);
}

.bookmark-btn {
  background: transparent;
  border: none;
  font-size: 18px;
  color: var(--text-muted);
  transition: color 0.2s, transform 0.2s;
}
.bookmark-btn:hover { transform: scale(1.2); }
.bookmark-btn.active { color: var(--warning); }

.card-actions { display: inline-flex; align-items: center; gap: 8px; }
.revision-btn {
  background: transparent;
  border: none;
  font-size: 16px;
  color: var(--text-muted);
  transition: color 0.2s, transform 0.2s;
}
.revision-btn:hover { transform: scale(1.15); color: var(--primary); }
.revision-btn.active { color: var(--primary); }

.pagination {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 8px;
  margin: 24px 0 6px;
  flex-wrap: wrap;
}

.page-btn {
  width: 36px;
  height: 36px;
  border: 1px solid var(--border);
  background: var(--bg-elev);
  color: var(--text);
  font-weight: 700;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: 0.2s;
}

.page-btn:hover:not(:disabled),
.page-btn.active {
  background: var(--premium-gradient);
  border-color: transparent;
  color: #fff;
  transform: translateY(-1px);
}

.page-btn:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

/* Type & badges */
.type-badge {
  background: var(--info);
  color: var(--hero-text);
  padding: 2px 8px;
  font-size: 11px;
  font-weight: 600;
}
.type-badge.MCQ { background: var(--type-mcq); }
.type-badge.MSQ { background: var(--type-msq); }
.type-badge.NAT { background: var(--type-nat); color: var(--type-nat-text); }

.difficulty-badge,
.status-badge {
  color: #fff;
  padding: 2px 8px;
  font-size: 11px;
  font-weight: 700;
}
.difficulty-badge.Easy { background: var(--success); }
.difficulty-badge.Medium { background: var(--warning); color: #1f2937; }
.difficulty-badge.Hard { background: var(--danger); }
.status-badge.New { background: var(--bg-soft); color: var(--text-muted); }
.status-badge.Attempted { background: var(--info); }
.status-badge.Correct { background: var(--success); }
.status-badge.Wrong { background: var(--danger); }

.section-badge,
.q-badge {
  background: var(--bg-soft);
  color: var(--text-muted);
  padding: 2px 8px;
  font-size: 11px;
  font-weight: 500;
}

/* ============================
   SEARCH RESULTS / SUGGESTIONS
   ============================ */
#searchResults { margin-top: 0; }

#searchResults:not(:empty) {
  position: relative;
  z-index: 25;
  background: var(--overlay-bg);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
  padding: 12px;
}

/* Keep question grid and right ad rail top-aligned on dashboards */
.ad-layout > #searchResults,
.ad-layout > .ad-rail {
  margin-top: 0;
  align-self: start;
}

mark {
  background: var(--accent);
  color: #073247;
  padding: 1px 3px;
  font-weight: 600;
}
[data-theme="dark"] mark { background: var(--accent); color: #052b41; }

.search-group-title {
  margin: 16px 0 6px;
  font-size: 12px;
  font-weight: 700;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

#searchSuggestions {
  position: absolute;
  top: calc(100% + 6px);
  left: 0; right: 0;
  background: var(--overlay-bg);
  color: var(--text);
  box-shadow: var(--shadow-lg);
  z-index: 1200;
  display: none;
  max-height: 320px;
  overflow-y: auto;
  font-size: 13px;
  border: 1px solid var(--border);
  backdrop-filter: none;
  -webkit-backdrop-filter: none;
  isolation: isolate;
}
.search-suggestions-inner { padding: 6px 0; }
.suggest-group { border-top: 1px solid var(--border); padding: 6px 0; }
.suggest-group:first-child { border-top: none; }
.suggest-title {
  padding: 4px 12px;
  font-weight: 700;
  color: var(--text-muted);
  font-size: 11px;
  text-transform: uppercase;
}
.suggest-item {
  padding: 7px 12px;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--text);
  background: transparent;
}
.suggest-item i { font-size: 11px; color: var(--text-muted); }
.suggest-item:hover,
.suggest-item.active { background: var(--overlay-soft); color: var(--primary); }
.suggest-item .badge-mini {
  margin-left: auto;
  font-size: 10px;
  background: var(--overlay-soft);
  color: var(--text-muted);
  padding: 1px 6px;
  }

.did-you-mean {
  color: var(--info);
  cursor: pointer;
  font-weight: 600;
  text-decoration: underline;
}

/* ============================
   SKELETON LOADING
   ============================ */
.skeleton {
  background: linear-gradient(90deg, var(--bg-soft) 25%, var(--border) 50%, var(--bg-soft) 75%);
  background-size: 200% 100%;
  animation: shimmer 1.4s infinite;
  }
@keyframes shimmer {
  0% { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}
.skeleton-card {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  padding: 16px;
  min-height: 150px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.skeleton-line { height: 12px; }

/* ============================
   EMPTY STATE
   ============================ */
.empty {
  text-align: center;
  padding: 50px 20px;
  color: var(--text-muted);
}
.empty .emoji { font-size: 3rem; margin-bottom: 10px; }
.empty h3 { color: var(--text); margin-bottom: 6px; }

/* ============================
   RIGHT PANEL (mobile)
   ============================ */
.right-panel {
  position: fixed;
  top: 60px;
  right: -300px;
  width: 280px;
  height: calc(100vh - 60px);
  background: var(--bg-elev);
  color: var(--text);
  padding: 18px;
  transition: right 0.3s;
  z-index: 999;
  box-shadow: var(--shadow-md);
  border-left: 1px solid var(--border);
  overflow-y: auto;
}
.right-panel.active { right: 0; }
.panel-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 18px;
  font-weight: 700;
}
.panel-header .close-panel { cursor: pointer; font-size: 18px; }
.panel-item {
  padding: 12px 14px;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-bottom: 1px solid var(--border);
  transition: 0.25s;
  }
.panel-item:hover { background: var(--bg-soft); transform: translateX(3px); }

/* Theme switch */
.switch {
  position: relative;
  width: 42px; height: 22px;
  background: var(--bg-soft);
  cursor: pointer;
  transition: background var(--transition);
  border: 1px solid var(--border);
  flex-shrink: 0;
}
.switch::after {
  content: "";
  position: absolute;
  width: 16px; height: 16px;
  background: var(--primary);
  top: 2px; left: 2px;
  transition: transform var(--transition);
}
[data-theme="dark"] .switch::after { transform: translateX(20px); background: var(--accent); }

/* ============================
   QUESTION DETAIL PAGE
   ============================ */
.breadcrumbs {
  margin-bottom: 14px;
  font-size: 13px;
  color: var(--text-muted);
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}
.breadcrumbs a { color: var(--primary); transition: 0.2s; }
.breadcrumbs a:hover { text-decoration: underline; }
.breadcrumbs .sep { opacity: 0.5; }

.q-card {
  background: var(--card-bg);
  padding: 26px;
  box-shadow: var(--card-shadow);
  margin-bottom: 18px;
  border: var(--card-border);
  position: relative;
  overflow: hidden;
}
.q-card::before {
  content: "";
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 4px;
  background: var(--premium-gradient);
}

.q-meta {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 16px;
  font-size: 13px;
  color: var(--text-muted);
}
.q-meta-left { display: flex; gap: 8px; flex-wrap: wrap; align-items: center; }

.q-section-title {
  font-size: 16px;
  font-weight: 700;
  margin: 18px 0 8px;
  color: var(--primary);
  display: flex;
  align-items: center;
  gap: 8px;
}

.q-question-text {
  font-size: 1.05rem;
  line-height: 1.7;
  margin: 8px 0 18px;
}

#answerArea {
  margin-top: 10px;
}

#answerArea:empty {
  margin-top: 0;
}

.options-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 16px;
}
.option-item {
  padding: 12px 16px;
  border: 1px solid var(--border);
  cursor: pointer;
  transition: 0.2s;
  display: flex;
  align-items: center;
  gap: 10px;
  background: var(--bg);
}
.option-item:hover { border-color: var(--primary); }
.option-item.selected { border-color: var(--primary); background: var(--bg-soft); }
.option-item.correct { border-color: var(--success); background: rgba(34,197,94,0.12); }
.option-item.wrong { border-color: var(--danger); background: rgba(239,68,68,0.12); }
.option-marker {
  width: 26px; height: 26px;
  background: var(--bg-soft);
  display: flex; align-items: center; justify-content: center;
  font-weight: 700;
  font-size: 12px;
  flex-shrink: 0;
}
.option-item.selected .option-marker { background: var(--primary); color: #fff; }
.option-item.correct .option-marker { background: var(--success); color: #fff; }
.option-item.wrong .option-marker { background: var(--danger); color: #fff; }

.nat-input {
  width: 100%;
  padding: 12px 14px;
  border: 1px solid var(--border);
  background: var(--bg);
  color: var(--text);
  font-size: 1rem;
  outline: none;
  margin-bottom: 12px;
}
.nat-input:focus { border-color: var(--primary); box-shadow: 0 0 0 3px var(--focus-ring); }

.q-toggle-btn {
  background: var(--premium-gradient);
  color: #fff;
  padding: 9px 14px;
  border: none;
  cursor: pointer;
  margin-top: 6px;
  transition: 0.25s;
  font-weight: 600;
  font-size: 13px;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}
.q-toggle-btn:hover { filter: saturate(1.08); }

.q-content-box {
  display: none;
  margin-top: 10px;
  padding: 14px;
  background: var(--bg-soft);
  border-left: 4px solid var(--primary-2);
  white-space: pre-line;
  line-height: 1.7;
  color: var(--text);
  animation: fadeIn 0.3s ease;
}

.q-content-box table,
.seo-explanation table {
  width: 100%;
  border-collapse: collapse;
  margin: 8px 0;
  background: var(--bg-elev);
}

.q-content-box th,
.q-content-box td,
.seo-explanation th,
.seo-explanation td {
  border: 1px solid var(--border);
  padding: 8px 10px;
  text-align: left;
  vertical-align: top;
}

.q-content-box th,
.seo-explanation th {
  background: var(--bg-soft);
  font-weight: 800;
}
@keyframes fadeIn { from { opacity: 0; transform: translateY(5px); } to { opacity: 1; transform: translateY(0); } }

.feedback-msg {
  padding: 10px 14px;
  margin-bottom: 12px;
  font-weight: 600;
  font-size: 14px;
}
.feedback-msg.correct { background: rgba(34,197,94,0.15); color: var(--success); }
.feedback-msg.wrong { background: rgba(239,68,68,0.15); color: var(--danger); }

#stopwatch {
  font-size: 14px;
  font-weight: 700;
  color: var(--primary);
  background: var(--bg-soft);
  padding: 6px 12px;
  font-family: "SF Mono", Menlo, monospace;
}

/* Next/Prev */
.q-nav {
  display: flex;
  justify-content: space-between;
  margin-top: 18px;
  gap: 10px;
}
.q-nav-btn {
  background: var(--bg-elev);
  color: var(--text);
  border: 1px solid var(--border);
  padding: 10px 18px;
  cursor: pointer;
  font-weight: 600;
  font-size: 14px;
  transition: 0.25s;
  display: inline-flex;
  align-items: center;
  gap: 8px;
}
.q-nav-btn:hover:not(:disabled) {
  background: var(--premium-gradient);
  color: #fff;
  border-color: transparent;
  transform: translateY(-1px);
}
.q-nav-btn:disabled { opacity: 0.4; cursor: not-allowed; }

/* ============================
   QUIZ MODAL
   ============================ */
.quiz-modal {
  position: fixed;
  inset: 0;
  background: rgba(6,10,20,0.68);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 2000;
  padding: 20px;
}
.quiz-modal.open { display: flex; }
.quiz-card {
  background: var(--bg-elev);
  padding: 26px;
  max-width: 720px;
  width: 100%;
  max-height: 92vh;
  overflow-y: auto;
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--border);
  position: relative;
  overflow-x: hidden;
  overflow-y: auto;
}
.quiz-card::before {
  content: "";
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 4px;
  background: var(--premium-gradient);
}
.quiz-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 12px;
}
.quiz-header h3 { font-size: 1.05rem; }
.quiz-close { font-size: 20px; cursor: pointer; color: var(--text-muted); background: none; border: none; }
.quiz-close:hover { color: var(--danger); }

.quiz-progress {
  height: 6px;
  background: var(--bg-soft);
  overflow: hidden;
  margin-bottom: 18px;
}
.quiz-progress-bar {
  height: 100%;
  background: var(--premium-gradient);
  transition: width 0.3s ease;
}

.quiz-result { text-align: center; padding: 14px 0; }
.quiz-result .score {
  font-size: 3rem;
  font-weight: 800;
  background: var(--premium-gradient);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.quiz-review {
  margin-top: 18px;
  text-align: left;
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.review-item {
  padding: 12px;
  border: 1px solid var(--border);
  font-size: 0.9rem;
  background: var(--bg);
}
.review-item.correct { border-left: 4px solid var(--success); }
.review-item.wrong { border-left: 4px solid var(--danger); }

/* ============================
   ASSESSMENT STUDIO PAGES
   ============================ */
.assessment-hero {
  display: flex;
  justify-content: space-between;
  gap: 24px;
  align-items: stretch;
  background: var(--hero-gradient);
  color: var(--hero-text);
  padding: 34px;
  box-shadow: var(--shadow-md);
  border: 1px solid color-mix(in srgb, var(--hero-text) 16%, transparent);
  margin-bottom: 22px;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--accent);
  text-transform: uppercase;
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.8px;
  margin-bottom: 8px;
}

.assessment-hero h1 {
  font-size: 30px;
  line-height: 1.1;
  margin-bottom: 8px;
}

.assessment-hero p {
  color: var(--hero-subtext);
  max-width: 620px;
  line-height: 1.6;
}

.assessment-hero-metrics {
  display: grid;
  grid-template-columns: repeat(3, minmax(90px, 1fr));
  gap: 10px;
  min-width: 320px;
}

.assessment-hero-metrics div,
.summary-card,
.history-card {
  background: var(--hero-stat-bg);
  border: 1px solid var(--hero-stat-border);
  padding: 16px;
}

.assessment-hero-metrics strong {
  display: block;
  font-size: 28px;
}

.assessment-hero-metrics span {
  display: block;
  font-size: 12px;
  color: var(--hero-subtext);
}

.assessment-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 280px;
  gap: 18px;
  align-items: start;
}

.assessment-panel,
.assessment-summary,
.history-panel,
.session-card {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
}

.assessment-panel,
.history-panel,
.session-card {
  padding: 22px;
}

.panel-title {
  display: flex;
  gap: 12px;
  align-items: flex-start;
  margin-bottom: 18px;
}

.panel-title > i {
  width: 38px;
  height: 38px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  background: var(--premium-gradient);
  flex-shrink: 0;
}

.panel-title h2 {
  font-size: 1.1rem;
  margin-bottom: 4px;
}

.panel-title p {
  color: var(--text-muted);
  font-size: 0.9rem;
}

.assessment-form {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.assessment-form label {
  display: flex;
  flex-direction: column;
  gap: 7px;
  color: var(--text-muted);
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.4px;
}

.assessment-form select,
.assessment-form input {
  width: 100%;
  min-height: 42px;
  border: 1px solid var(--border);
  background: var(--input-bg);
  color: var(--input-text);
  padding: 0 12px;
  outline: none;
  font-size: 14px;
  text-transform: none;
  font-weight: 600;
  letter-spacing: 0;
}

.assessment-form select:focus,
.assessment-form input:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--focus-ring);
}

.assessment-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 18px;
}

.assessment-summary {
  padding: 14px;
  display: grid;
  gap: 12px;
}

.summary-card {
  background: var(--bg-soft);
  border-color: var(--border);
}

.summary-card span,
.history-card span,
.history-card small {
  display: block;
  color: var(--text-muted);
  font-size: 12px;
  margin-top: 4px;
}

.summary-card strong,
.history-card strong {
  font-size: 28px;
  color: var(--text);
}

.assessment-session {
  display: none;
  margin-top: 22px;
}

.assessment-session.active {
  display: block;
}

.session-card {
  position: relative;
  overflow: hidden;
}

.session-card::before {
  content: "";
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 4px;
  background: var(--premium-gradient);
}

.session-topbar {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  align-items: flex-start;
  margin-bottom: 14px;
}

.session-topbar h2 {
  font-size: 1.15rem;
}

.session-timer {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 9px 12px;
  color: var(--danger);
  background: var(--bg-soft);
  font-weight: 800;
  font-family: "SF Mono", Menlo, monospace;
  white-space: nowrap;
}

.history-panel {
  margin-top: 22px;
}

.history-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 12px;
}

.history-card {
  background: var(--bg-soft);
  border-color: var(--border);
}

.empty.compact {
  padding: 22px 12px;
}

/* ============================
   AUTH PAGES
   ============================ */
.auth-page {
  min-height: 100vh;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 440px;
  gap: 28px;
  align-items: center;
  padding: 42px;
  background:
    radial-gradient(circle at 15% 20%, rgba(40,84,216,0.14), transparent 32%),
    linear-gradient(135deg, var(--bg-subtle), var(--bg));
}

.auth-brand {
  min-height: calc(100vh - 84px);
  padding: 46px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  background: var(--hero-gradient);
  color: var(--hero-text);
  box-shadow: var(--shadow-lg);
  border: 1px solid color-mix(in srgb, var(--hero-text) 16%, transparent);
}

.auth-logo {
  color: var(--hero-text);
  font-weight: 900;
  font-size: 1.2rem;
  letter-spacing: 0.4px;
  margin-bottom: 54px;
  display: inline-flex;
  align-items: center;
}

.auth-brand h1 {
  font-size: clamp(2rem, 5vw, 4rem);
  line-height: 1;
  margin-bottom: 14px;
}

.auth-brand p {
  max-width: 620px;
  color: var(--hero-subtext);
  line-height: 1.7;
  font-size: 1rem;
}

.auth-demo-box {
  margin-top: 30px;
  max-width: 420px;
  padding: 16px;
  background: rgba(255,255,255,0.12);
  border: 1px solid rgba(255,255,255,0.18);
  display: grid;
  gap: 6px;
}

.auth-demo-box strong,
.auth-demo-box span {
  display: block;
}

.auth-demo-box span {
  color: var(--hero-subtext);
  font-size: 0.92rem;
}

.auth-card {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  padding: 30px;
  box-shadow: var(--shadow-lg);
  position: relative;
  overflow: hidden;
}

.auth-card::before {
  content: "";
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 4px;
  background: var(--premium-gradient);
}

.auth-form {
  display: grid;
  gap: 14px;
}

.auth-form label {
  display: grid;
  gap: 7px;
  color: var(--text-muted);
  font-size: 12px;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.4px;
}

.auth-form input,
.auth-form select {
  width: 100%;
  min-height: 44px;
  border: 1px solid var(--border);
  background: var(--input-bg);
  color: var(--input-text);
  padding: 0 13px;
  outline: none;
  font-size: 14px;
  font-weight: 600;
}

.auth-form input:focus,
.auth-form select:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--focus-ring);
}

.auth-submit {
  justify-content: center;
  min-height: 44px;
}

.auth-submit:disabled {
  opacity: 0.7;
  cursor: wait;
}

.auth-message {
  display: none;
  padding: 10px 12px;
  font-size: 0.9rem;
  font-weight: 700;
}

.auth-message.success,
.auth-message.error,
.auth-message.warning,
.auth-message.info {
  display: block;
}

.auth-message.success { background: rgba(34,197,94,0.14); color: var(--success); }
.auth-message.error { background: rgba(239,68,68,0.14); color: var(--danger); }
.auth-message.warning { background: rgba(245,158,11,0.14); color: var(--warning); }
.auth-message.info { background: var(--bg-soft); color: var(--text-muted); }

.auth-switch {
  text-align: center;
  margin-top: 18px;
  color: var(--text-muted);
  font-size: 0.92rem;
}

.auth-switch a {
  color: var(--primary);
  font-weight: 800;
}

/* ============================
   APP UTILITY MODALS
   ============================ */
.app-modal {
  position: fixed;
  inset: 0;
  z-index: 2200;
  display: none;
  align-items: center;
  justify-content: center;
  padding: 20px;
  background: rgba(6,10,20,0.68);
}

.app-modal.open {
  display: flex;
}

.app-modal-card {
  width: min(560px, 100%);
  max-height: 88vh;
  overflow-y: auto;
  background: var(--bg-elev);
  color: var(--text);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-lg);
  padding: 24px;
  position: relative;
}

.app-modal-card::before {
  content: "";
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 4px;
  background: var(--premium-gradient);
}

.app-modal-close {
  position: absolute;
  top: 12px;
  right: 12px;
  width: 34px;
  height: 34px;
  border: 1px solid var(--border);
  background: var(--bg-soft);
  color: var(--text-muted);
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.app-modal-close:hover {
  color: var(--danger);
  border-color: var(--danger);
}

.app-modal-title {
  padding-right: 42px;
}

.utility-list {
  display: grid;
  gap: 12px;
}

.utility-item {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  width: 100%;
  text-align: left;
  color: var(--text);
  background: var(--bg-soft);
  border: 1px solid var(--border);
  padding: 14px;
}

.utility-item > i {
  width: 34px;
  height: 34px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  background: var(--premium-gradient);
  flex-shrink: 0;
}

.utility-item strong,
.utility-item span {
  display: block;
}

.utility-item span,
.utility-empty p {
  color: var(--text-muted);
  line-height: 1.6;
  font-size: 0.92rem;
  margin-top: 3px;
}

.utility-button {
  cursor: pointer;
  font-family: inherit;
}

.utility-button:hover,
.utility-item:hover {
  border-color: var(--primary);
}

.utility-empty h3 {
  margin-bottom: 6px;
}

.profile-card-mini {
  display: flex;
  gap: 14px;
  align-items: center;
  padding: 16px;
  background: var(--bg-soft);
  border: 1px solid var(--border);
}

.profile-card-mini p {
  color: var(--text-muted);
  margin: 4px 0 8px;
}

.profile-avatar {
  width: 58px;
  height: 58px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  background: var(--premium-gradient);
  font-size: 1.4rem;
  font-weight: 900;
}

/* ============================
   CONTENT PAGES
   ============================ */
.content-hero {
  background: var(--hero-gradient);
  color: var(--hero-text);
  padding: 36px;
  box-shadow: var(--shadow-md);
  border: 1px solid color-mix(in srgb, var(--hero-text) 16%, transparent);
  margin-bottom: 22px;
}

.content-hero h1 {
  font-size: clamp(1.8rem, 4vw, 3rem);
  line-height: 1.08;
  margin-bottom: 10px;
}

.content-hero p {
  max-width: 760px;
  color: var(--hero-subtext);
  line-height: 1.7;
}

.content-grid,
.contact-layout {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
}

.contact-layout {
  grid-template-columns: minmax(0, 1.4fr) minmax(280px, 0.6fr);
}

.policy-stack {
  display: grid;
  gap: 14px;
}

.content-card {
  background: var(--card-bg);
  border: var(--card-border);
  padding: 22px;
  box-shadow: var(--card-shadow);
  position: relative;
  overflow: hidden;
  transition: transform 0.22s ease, box-shadow 0.22s ease, border-color 0.22s ease;
}

.content-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--card-shadow-hover);
  border-color: var(--primary);
}

.content-card::before {
  content: "";
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 3px;
  background: var(--premium-gradient);
}

.content-card > i {
  width: 42px;
  height: 42px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  background: var(--premium-gradient);
  margin-bottom: 14px;
}

.content-card h2 {
  font-size: 1.1rem;
  margin-bottom: 8px;
}

.content-card p {
  color: var(--text-muted);
  line-height: 1.7;
  margin-bottom: 8px;
}

.content-card code {
  color: var(--primary);
  font-weight: 800;
}

.seo-question {
  display: block;
}

.seo-question > * + * {
  margin-top: 14px;
}

.seo-question .eyebrow {
  margin-top: 0;
}

.seo-question h1 {
  margin: 6px 0 0;
  line-height: 1.22;
}

.seo-question .card-meta {
  margin-top: 12px;
}

.seo-question h2 {
  margin: 12px 0 0;
}

.seo-options {
  list-style: none;
  counter-reset: option;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  padding: 0;
  margin: 12px 0 18px;
}

.seo-option {
  counter-increment: option;
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  align-items: center;
  text-align: left;
  gap: 10px;
  min-height: 54px;
  padding: 12px 14px;
  border: 1px solid var(--border);
  background: var(--bg-soft);
  color: var(--text);
  line-height: 1.45;
  word-break: break-word;
  cursor: pointer;
  font: inherit;
  transition: transform .18s ease, border-color .18s ease, box-shadow .18s ease, background .18s ease;
}

.seo-option::before {
  content: counter(option, upper-alpha);
  width: 34px;
  height: 34px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  background: var(--premium-gradient);
  font-weight: 800;
}

.seo-option:hover:not(:disabled) {
  border-color: var(--primary);
  box-shadow: var(--shadow-sm);
  transform: translateY(-1px);
}

.seo-option:disabled {
  cursor: default;
  opacity: 1;
}

.seo-option.correct,
.seo-option.selected-correct {
  border-color: var(--success);
  background: color-mix(in srgb, var(--success) 12%, var(--bg-soft));
}

.seo-option.selected-wrong {
  border-color: var(--danger);
  background: color-mix(in srgb, var(--danger) 12%, var(--bg-soft));
}

.seo-result {
  min-height: 24px;
  margin: 4px 0 14px;
  font-weight: 800;
}

.seo-question .assessment-actions {
  margin-top: 16px;
}

.seo-result.correct { color: var(--success); }
.seo-result.wrong { color: var(--danger); }

.seo-explanation {
  margin-top: 16px;
  padding-top: 14px;
  border-top: 1px solid var(--border);
}

.seo-explanation p {
  white-space: pre-line;
}

.seo-explanation .rich-content {
  white-space: pre-line;
}

.is-hidden {
  display: none !important;
}

.analytics-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
  gap: 14px;
  margin-bottom: 18px;
}

.mini-bar {
  height: 8px;
  background: var(--bg-soft);
  overflow: hidden;
}
.mini-bar span { display: block; height: 100%; background: var(--premium-gradient); }

.admin-json {
  width: 100%;
  border: 1px solid var(--border);
  background: var(--input-bg);
  color: var(--input-text);
  padding: 14px;
  font: 13px "SF Mono", Menlo, monospace;
  resize: vertical;
}

.similar-list {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: var(--grid-gap-md);
  margin-top: 12px;
}
.similar-item {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 10px;
  min-height: var(--similar-card-h-desktop);
  height: var(--similar-card-h-desktop);
  padding: 15px;
  border: var(--card-border);
  background: var(--card-bg);
  box-shadow: var(--card-shadow);
  color: var(--text);
  text-decoration: none;
  overflow: hidden;
  transition: transform 0.22s ease, box-shadow 0.22s ease, border-color 0.22s ease;
}
.similar-item strong,
.similar-item span { display: block; }
.similar-item strong {
  line-height: 1.45;
  display: -webkit-box;
  -webkit-line-clamp: 5;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.similar-item span {
  color: color-mix(in srgb, var(--text) 72%, var(--text-muted) 28%);
  font-size: 12px;
  margin-top: auto;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.similar-item:hover,
.seo-nav-card:hover {
  border-color: var(--primary);
  transform: translateY(-4px);
  box-shadow: var(--card-shadow-hover);
}

.seo-nav-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
  align-items: center;
  margin: 8px 0 14px;
}

.seo-nav-grid .seo-nav-card:first-child { justify-self: start; }
.seo-nav-grid .seo-nav-card:last-child { justify-self: end; }

.seo-nav-card {
  color: var(--primary);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 32px;
  height: 32px;
  padding: 0 12px;
  border: 1px solid var(--primary);
  background: color-mix(in srgb, var(--primary) 8%, var(--bg-elev));
  box-shadow: 0 4px 12px rgba(16, 33, 63, 0.08);
  transition: transform 0.18s ease, box-shadow 0.18s ease, background 0.18s ease, color 0.18s ease, border-color 0.18s ease;
}

.seo-nav-card strong {
  line-height: 1.35;
  font-size: 0.9rem;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.seo-nav-card small {
  color: var(--text-muted);
  font-size: 11px;
  display: -webkit-box;
  -webkit-line-clamp: 1;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.seo-nav-card strong,
.seo-nav-card small {
  display: none;
}

.seo-nav-card .eyebrow {
  margin: 0;
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0;
  color: inherit;
  text-transform: none;
  line-height: 1;
}

.seo-nav-card:hover,
.seo-nav-card:focus-visible {
  transform: translateY(-1px);
  color: var(--hero-text);
  background: var(--premium-gradient);
  border-color: transparent;
  box-shadow: 0 8px 18px rgba(16, 33, 63, 0.16);
}

.seo-nav-card:focus-visible {
  outline: 2px solid var(--focus-ring);
  outline-offset: 2px;
}

.seo-study-strip {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.comments-box {
  display: grid;
  gap: 14px;
}

.comments-list {
  display: grid;
  gap: 10px;
}

.comment-item {
  background: var(--bg-soft);
  border: 1px solid var(--border);
  padding: 14px;
}

.comment-meta {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  color: var(--text-muted);
  font-size: 12px;
  margin-bottom: 8px;
}

.comment-meta strong {
  color: var(--text);
}

.comment-item p {
  line-height: 1.65;
  margin-bottom: 10px;
}

.comment-delete {
  border: none;
  background: transparent;
  color: var(--danger);
  font-size: 12px;
  font-weight: 800;
}

.comment-form {
  display: grid;
  gap: 10px;
}

.comment-form textarea {
  width: 100%;
  border: 1px solid var(--border);
  background: var(--input-bg);
  color: var(--input-text);
  padding: 13px;
  outline: none;
  resize: vertical;
  font: inherit;
}

.comment-form textarea:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--focus-ring);
}

.discussion-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
}

.discussion-toolbar .btn.active {
  color: var(--primary);
  border-color: var(--primary);
  background: color-mix(in srgb, var(--primary) 12%, var(--bg-elev));
}

.discussion-status {
  min-height: 20px;
  color: var(--text-muted);
  font-size: 0.9rem;
}

.discussion-status[data-type="success"] { color: var(--success); }
.discussion-status[data-type="error"] { color: var(--danger); }

.moderation-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}

.moderation-list {
  display: grid;
  gap: 12px;
  margin-top: 12px;
}

.moderation-item {
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--bg-elev);
  padding: 14px;
}

.moderation-item p {
  margin: 8px 0;
  color: var(--text);
}

.moderation-item small {
  color: var(--text-muted);
}

@media (max-width: 900px) {
  .moderation-grid {
    grid-template-columns: 1fr;
  }
}

.leaderboard {
  display: grid;
  gap: 10px;
}
.leaderboard div {
  display: flex;
  justify-content: space-between;
  padding: 12px;
  background: var(--bg-soft);
  color: var(--text);
}
.leaderboard span {
  color: var(--primary);
  font-weight: 900;
}

/* ============================
   SEO LANDING PAGE
   ============================ */
.landing-nav {
  width: min(1180px, calc(100% - 32px));
  margin: 12px auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  min-height: 56px;
  padding: 8px 14px;
  border: 1px solid var(--border);
  background:
    linear-gradient(132deg, color-mix(in srgb, var(--overlay-bg) 96%, #ffffff 4%), color-mix(in srgb, var(--overlay-soft) 92%, #ffffff 8%));
  box-shadow: var(--shadow-md);
  backdrop-filter: none;
  -webkit-backdrop-filter: none;
}

.landing-nav .auth-logo {
  color: var(--text);
  margin: 0;
  line-height: 1;
}

.landing-menu-toggle {
  display: none;
}

.landing-nav nav {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: nowrap;
}

.landing-nav nav a:not(.btn) {
  color: color-mix(in srgb, var(--text) 82%, var(--text-muted) 18%);
  font-weight: 700;
  white-space: nowrap;
  min-height: 36px;
  display: inline-flex;
  align-items: center;
}

.landing-nav nav a:hover {
  color: var(--primary);
}

.landing-theme-toggle {
  width: 36px;
  min-width: 36px;
  min-height: 36px;
  border: 1px solid var(--btn-surface-border);
  background: var(--btn-surface-bg);
  color: var(--btn-surface-text);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 7px;
  font-weight: 800;
  box-shadow: var(--shadow-sm);
  line-height: 1;
}

.landing-theme-toggle span {
  display: none;
}

.landing-theme-toggle i {
  font-size: 0.95rem;
}

.landing-theme-toggle:hover {
  border-color: var(--primary);
  color: var(--primary);
  background: var(--btn-surface-bg-hover);
  box-shadow: var(--shadow-sm);
}

.course-menu {
  position: relative;
}

.course-menu-btn {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  border: 1px solid transparent;
  border-radius: var(--radius);
  background: transparent;
  color: color-mix(in srgb, var(--text) 82%, var(--text-muted) 18%);
  font: inherit;
  font-weight: 800;
  min-height: 36px;
  padding: 0 2px;
}

.course-menu-btn:hover {
  color: var(--primary);
}

.course-menu-panel {
  position: absolute;
  top: calc(100% + 8px);
  left: 0;
  width: 260px;
  display: none;
  grid-template-columns: 1fr;
  gap: 3px;
  padding: 10px;
  border: 1px solid var(--border);
  background: color-mix(in srgb, var(--overlay-bg) 96%, #ffffff 4%);
  box-shadow: var(--shadow-md);
  max-height: min(76vh, 520px);
  overflow-y: auto;
  backdrop-filter: none;
  -webkit-backdrop-filter: none;
  isolation: isolate;
}

.course-menu.is-course-open .course-menu-panel {
  display: grid;
}

.course-menu-panel a {
  padding: 10px 12px;
  color: var(--text);
  font-weight: 800;
}

.course-menu-panel a:hover {
  background: var(--overlay-soft);
}

.course-strip {
  width: min(1180px, calc(100% - 32px));
  margin: 10px auto 18px;
  display: flex;
  gap: 10px;
  overflow-x: auto;
  padding: 4px 2px 12px;
  scrollbar-width: thin;
}

/* Consistent section spacing for analytics and other stacked content blocks */
#analyticsRoot > section + section,
#courseQuestionRoot > section + section {
  margin-top: 18px;
}

.course-strip a {
  flex: 0 0 auto;
  padding: 9px 13px;
  border: 1px solid var(--border);
  background: var(--bg-elev);
  color: var(--text);
  font-weight: 800;
  box-shadow: var(--shadow-sm);
}

.course-strip a:hover {
  border-color: var(--primary);
  color: var(--primary);
}

.landing-page {
  width: min(1180px, calc(100% - 32px));
  margin: 0 auto 36px;
}

.landing-hero {
  min-height: 540px;
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(260px, 0.85fr);
  align-items: center;
  gap: 32px;
  color: var(--hero-text);
  background: var(--hero-gradient);
  padding: clamp(28px, 6vw, 58px);
  box-shadow: var(--shadow-lg);
  border: 1px solid color-mix(in srgb, var(--hero-text) 16%, transparent);
  margin-bottom: 26px;
}

.landing-hero h1 {
  font-size: clamp(2.2rem, 6vw, 4.8rem);
  line-height: 0.98;
  max-width: 850px;
  margin-bottom: 18px;
}

.landing-hero p {
  color: var(--hero-subtext);
  max-width: 680px;
  line-height: 1.75;
  font-size: 1.05rem;
  margin-bottom: 22px;
}

.landing-hero img {
  width: min(100%, 360px);
  justify-self: center;
  filter: drop-shadow(0 24px 40px rgba(0,0,0,0.25));
}

.landing-footer {
  width: min(1180px, calc(100% - 32px));
  margin: 14px auto 24px;
  padding: 16px 20px;
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 10px 12px;
  flex-wrap: wrap;
  border: 1px solid var(--border);
  background:
    linear-gradient(135deg, color-mix(in srgb, var(--primary) 8%, transparent), transparent 55%),
    var(--bg-elev);
  box-shadow: var(--shadow-sm);
}

.landing-footer a {
  color: var(--text-muted);
  min-height: 36px;
  padding: 0 12px;
  display: inline-flex;
  align-items: center;
  border: 1px solid transparent;
  font-size: 0.9rem;
  font-weight: 700;
  transition: color var(--transition), border-color var(--transition), background var(--transition);
}

.landing-footer a:hover {
  color: var(--primary);
  border-color: var(--border);
  background: var(--overlay-soft);
}

.landing-footer span {
  flex: 1 1 100%;
  text-align: center;
  font-size: 0.82rem;
  color: var(--text-muted);
  padding-top: 8px;
  border-top: 1px solid var(--border);
}

.app-footer {
  width: auto;
  max-width: none;
  margin: 10px 30px 22px 318px;
}

/* ============================
   PORTAL HOME
   ============================ */
.portal-page {
  display: grid;
  gap: 22px;
}

.portal-nav {
  position: sticky;
  top: 12px;
  z-index: 30;
  backdrop-filter: blur(16px);
}

.portal-hero {
  padding: 42px 28px;
  border: 1px solid var(--border);
  background:
    linear-gradient(135deg, color-mix(in srgb, var(--primary) 10%, transparent), transparent 42%),
    var(--bg-elev);
  box-shadow: var(--shadow-sm);
}

.portal-hero h1 {
  max-width: 760px;
  margin: 10px auto 10px;
  text-align: center;
  font-size: clamp(2rem, 5vw, 3.8rem);
  line-height: 1.05;
}

.portal-hero .eyebrow,
.portal-hero p {
  display: block;
  text-align: center;
}

.portal-hero p {
  max-width: 720px;
  margin: 0 auto 24px;
  color: var(--text-muted);
  line-height: 1.7;
}

.portal-search {
  width: min(780px, 100%);
  min-height: 58px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 44px minmax(0, 1fr) auto;
  align-items: center;
  gap: 8px;
  padding: 7px;
  border: 1px solid var(--border);
  background: var(--input-bg);
  box-shadow: var(--shadow-sm);
}

.portal-search i {
  color: var(--primary);
  text-align: center;
}

.portal-search input[type="search"] {
  width: 100%;
  border: 0;
  outline: 0;
  background: transparent;
  color: var(--input-text);
  font: inherit;
}

.portal-search button {
  min-height: 42px;
  border: 1px solid transparent;
  border-radius: var(--radius);
  padding: 0 18px;
  color: var(--btn-primary-text);
  background: var(--btn-primary-bg);
  font-weight: 800;
  box-shadow: var(--shadow-sm);
  cursor: pointer;
}

.portal-search button:hover {
  filter: saturate(1.06);
  transform: translateY(-1px);
}

.portal-search-results {
  width: min(780px, 100%);
  margin: 12px auto 0;
  display: grid;
  gap: 8px;
}

.portal-search-results a,
.portal-search-results p {
  padding: 12px 14px;
  border: 1px solid var(--border);
  background: var(--bg-elev);
  color: var(--text);
  box-shadow: var(--shadow-sm);
}

.portal-search-results span {
  display: block;
  margin-top: 3px;
  color: var(--text-muted);
  font-size: 12px;
}

.portal-chips {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px;
  margin-top: 18px;
}

.portal-chips a {
  padding: 9px 13px;
  border: 1px solid var(--border);
  background: var(--bg-soft);
  color: var(--text);
  font-weight: 800;
  font-size: 0.9rem;
}

.portal-quick-grid,
.portal-subject-grid,
.portal-plan-grid {
  display: grid;
  gap: 14px;
}

.portal-quick-grid {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

.portal-tile,
.portal-subject-grid a {
  color: var(--text);
  text-decoration: none;
  border: 1px solid var(--border);
  background: var(--bg-elev);
  box-shadow: var(--shadow-sm);
  transition: transform .18s ease, border-color .18s ease, box-shadow .18s ease;
}

.portal-tile {
  min-height: 180px;
  display: grid;
  align-content: start;
  gap: 12px;
  padding: 20px;
}

.portal-tile.featured {
  border-color: var(--primary);
}

.portal-tile i,
.portal-subject-grid i {
  width: 42px;
  height: 42px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  background: var(--premium-gradient);
}

.portal-tile span,
.portal-subject-grid strong {
  font-weight: 900;
}

.portal-tile strong,
.portal-subject-grid span {
  color: var(--text-muted);
  line-height: 1.55;
}

.portal-tile:hover,
.portal-subject-grid a:hover,
.portal-chips a:hover {
  transform: translateY(-2px);
  border-color: var(--primary);
  box-shadow: var(--shadow-md);
}

.portal-section-head {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 16px;
  margin-top: 8px;
}

.portal-section-head h2 {
  font-size: clamp(1.5rem, 3vw, 2.2rem);
  margin-top: 6px;
}

.portal-subject-grid {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

.portal-subject-grid a {
  min-height: 150px;
  padding: 18px;
  display: grid;
  align-content: start;
  gap: 10px;
}

.portal-subject-grid a.is-dimmed {
  opacity: 0.36;
}

.portal-subject-grid a.is-search-match {
  border-color: var(--primary);
  box-shadow: var(--shadow-md);
}

.portal-plan-grid {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.portal-ad-grid {
  display: grid !important;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
  margin: 14px 0 22px;
}

.portal-ad-grid .ad-slot {
  min-height: 250px;
  align-content: center;
  border: 2px solid color-mix(in srgb, var(--warning) 60%, var(--primary) 40%);
  box-shadow: var(--shadow-lg);
  background: linear-gradient(
    135deg,
    color-mix(in srgb, var(--bg-elev) 85%, #ffffff 15%),
    color-mix(in srgb, var(--bg-soft) 78%, #ffffff 22%)
  );
  position: relative;
}

.portal-ad-grid .ad-slot p {
  margin: 0;
  color: color-mix(in srgb, var(--text) 72%, var(--text-muted) 28%);
  line-height: 1.5;
}

.portal-ad-grid .ad-slot span {
  font-size: 12px;
  letter-spacing: 1px;
}

.portal-ad-grid .ad-slot strong {
  font-size: 1.35rem;
  line-height: 1.2;
}

.portal-ad-grid .ad-slot::before {
  content: "AD SLOT";
  position: absolute;
  top: 8px;
  right: 10px;
  font-size: 10px;
  letter-spacing: 1px;
  font-weight: 900;
  color: var(--warning);
}

.course-question-page {
  display: grid;
  gap: 18px;
}

.course-strip a.active {
  border-color: var(--primary);
  color: var(--primary);
  box-shadow: var(--shadow-md);
}

.course-ad-strip {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.course-question-root {
  display: grid;
  gap: 18px;
}

.course-chapter-card {
  scroll-margin-top: 90px;
}

.course-chapter-head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 14px;
  margin-bottom: 14px;
}

.course-topic-block {
  display: grid;
  gap: 10px;
  padding-top: 14px;
  border-top: 1px solid var(--border);
}

.course-topic-block + .course-topic-block {
  margin-top: 16px;
}

.course-topic-block h3 {
  font-size: 1rem;
}

.course-question-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: var(--grid-gap-sm);
}

.course-question-card {
  display: grid;
  gap: 8px;
  align-content: space-between;
  min-height: var(--course-card-h-desktop);
  height: var(--course-card-h-desktop);
  padding: 12px;
  border: var(--card-border);
  background: var(--card-bg);
  box-shadow: var(--card-shadow);
  color: var(--text);
  text-decoration: none;
  transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
}

.course-question-card:hover,
.course-question-card:focus-visible {
  transform: translateY(-2px);
  box-shadow: var(--card-shadow-hover);
  border-color: var(--primary);
}

.course-question-card strong {
  line-height: 1.45;
  display: -webkit-box;
  -webkit-line-clamp: 4;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.course-question-card span {
  color: color-mix(in srgb, var(--text) 72%, var(--text-muted) 28%);
  font-size: 12px;
  display: -webkit-box;
  -webkit-line-clamp: 1;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

/* ============================
   FREE / PAID PLAN UI
   ============================ */
.plan-badge {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 7px 11px;
  font-size: 12px;
  font-weight: 900;
  margin-bottom: 12px;
  background: rgba(255,255,255,0.14);
  border: 1px solid rgba(255,255,255,0.18);
}

.plan-badge.paid {
  color: #fff3c4;
}

.plan-badge.free {
  color: #dbeafe;
}

.ad-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 300px;
  gap: 18px;
  align-items: start;
  padding-right: 0;
}

.ad-rail {
  display: grid;
  gap: 14px;
  position: sticky;
  top: 78px;
  align-content: start;
  padding-right: 0;
  width: 100%;
  max-width: 300px;
}

.ad-slot {
  min-height: 170px;
  display: grid;
  place-items: center;
  text-align: center;
  gap: 6px;
  background: linear-gradient(
    135deg,
    color-mix(in srgb, var(--bg-elev) 86%, #ffffff 14%),
    color-mix(in srgb, var(--bg-soft) 82%, #ffffff 18%)
  );
  border: 1px solid color-mix(in srgb, var(--border) 75%, var(--primary) 25%);
  color: var(--text);
  padding: 18px;
  box-shadow: var(--shadow-sm);
}

.ad-slot.wide {
  min-height: 90px;
  margin-bottom: 18px;
}

.ad-slot span {
  text-transform: uppercase;
  letter-spacing: 0.8px;
  font-size: 11px;
  font-weight: 900;
  color: var(--warning);
}

.ad-slot strong {
  color: var(--text);
}

.ad-slot .slot-cta {
  margin-top: 8px;
}

.upgrade-card {
  background: linear-gradient(
    150deg,
    color-mix(in srgb, var(--bg-elev) 88%, #ffffff 12%),
    color-mix(in srgb, var(--bg-soft) 84%, #ffffff 16%)
  );
  border: 1px solid color-mix(in srgb, var(--border) 70%, var(--primary) 30%);
  padding: 18px;
  box-shadow: var(--shadow-md);
}

.upgrade-card > i {
  width: 42px;
  height: 42px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  background: var(--premium-gradient);
  margin-bottom: 12px;
}

.upgrade-card h3 {
  margin-bottom: 6px;
  color: var(--text);
}

.upgrade-card p {
  color: var(--text-muted);
  line-height: 1.6;
  margin-bottom: 14px;
}

.free-toolbar .filter-chips {
  justify-content: flex-end;
}

.pricing-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}

.pricing-featured {
  border-color: var(--primary);
  box-shadow: var(--shadow-md);
}

.paid-signin-strip {
  margin-top: 18px;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
  padding: 22px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
}

.paid-signin-strip h2 {
  margin-bottom: 6px;
}

.paid-signin-strip p {
  color: var(--text-muted);
  line-height: 1.6;
}

.contact-form {
  display: grid;
  gap: 14px;
}

.contact-form label {
  display: grid;
  gap: 7px;
  color: var(--text-muted);
  font-size: 12px;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.4px;
}

.contact-form input,
.contact-form select,
.contact-form textarea {
  width: 100%;
  border: 1px solid var(--border);
  background: var(--input-bg);
  color: var(--input-text);
  padding: 12px 13px;
  outline: none;
  font-size: 14px;
  font-weight: 600;
  resize: vertical;
}

.contact-form input:focus,
.contact-form select:focus,
.contact-form textarea:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--focus-ring);
}

/* ============================
   FOOTER
   ============================ */
.footer {
  background: var(--bg-elev);
  border-top: 1px solid var(--border);
  padding: 32px 24px 16px;
  margin-top: 40px;
  margin-left: 300px;
  transition: margin 0.3s;
}
.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 26px;
  max-width: 1200px;
  margin: 0 auto;
}
.footer h4 { margin-bottom: 12px; font-size: 0.95rem; color: var(--primary); }
.footer ul { list-style: none; }
.footer li { padding: 4px 0; font-size: 0.88rem; color: var(--text-muted); }
.footer li a:hover { color: var(--primary); }
.footer p { font-size: 0.88rem; color: var(--text-muted); }

.social { display: flex; gap: 10px; margin-top: 8px; }
.social a {
  width: 34px; height: 34px;
  background: var(--bg-soft);
  display: flex; align-items: center; justify-content: center;
  color: var(--text-muted);
  transition: 0.25s;
}
.social a:hover { background: var(--premium-gradient); color: #fff; }

.copyright {
  text-align: center;
  margin-top: 22px;
  padding-top: 14px;
  border-top: 1px solid var(--border);
  font-size: 0.82rem;
  color: var(--text-muted);
}

/* ============================
   AI ASSISTANT
   ============================ */
.ai-assistant {
  position: fixed;
  right: 24px;
  bottom: 84px;
  z-index: 1800;
  isolation: isolate;
}

.ai-assistant-fab {
  width: 54px;
  height: 54px;
  border: 1px solid var(--border);
  background: var(--premium-gradient);
  color: var(--hero-text);
  box-shadow: var(--shadow-lg), 0 0 0 1px color-mix(in srgb, var(--primary) 35%, transparent);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 19px;
  transition: transform var(--transition), box-shadow var(--transition), filter var(--transition);
}

.ai-assistant-fab:hover {
  transform: translateY(-2px);
  filter: saturate(1.08);
  box-shadow: var(--shadow-lg), 0 0 0 1px color-mix(in srgb, var(--primary) 50%, transparent);
}

.ai-assistant-fab.hidden {
  display: none;
}

.ai-assistant-panel {
  display: block;
  position: fixed;
  right: 0;
  top: var(--ai-assistant-top);
  width: 40vw;
  height: calc(100dvh - var(--ai-assistant-top) - var(--ai-assistant-bottom-gap));
  min-height: 360px;
  max-height: none;
  border-left: 1px solid var(--border);
  border-top: 0;
  border-right: 0;
  border-bottom: 0;
  background: var(--bg-elev);
  color: var(--text);
  box-shadow: var(--shadow-md);
  backdrop-filter: blur(16px) saturate(140%);
  -webkit-backdrop-filter: blur(16px) saturate(140%);
  overflow: hidden;
  transform: translateX(104%);
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transition: transform var(--transition), opacity var(--transition), visibility 0s linear 0.25s;
}

.ai-assistant-panel.open {
  transform: translateX(0);
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
  transition: transform var(--transition), opacity var(--transition);
}

.ai-assistant-panel-inner {
  height: 100%;
  padding: 18px;
  display: grid;
  grid-template-rows: auto auto minmax(0, 1fr) auto auto;
}

.ai-assistant-head {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  align-items: flex-start;
  padding: 0;
  margin-bottom: 6px;
}

.ai-assistant-head strong {
  display: block;
  font-size: 1.12rem;
  font-weight: 800;
  color: var(--text);
}

.ai-assistant-head span {
  display: block;
  margin-top: 3px;
  font-size: 0.86rem;
  color: var(--text-muted);
}

.ai-assistant-head button {
  width: 34px;
  height: 34px;
  border: 0;
  background: transparent;
  color: var(--text-muted);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
}

.ai-assistant-head button:hover {
  color: var(--danger);
}

.ai-assistant-chips {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
  border: 1px solid var(--border);
  overflow: hidden;
}

.ai-assistant-chips button {
  width: 100%;
  min-height: 52px;
  padding: 0 14px;
  border: 0;
  border-bottom: 1px solid var(--border);
  background: var(--bg-elev);
  color: var(--text);
  font-size: 1.02rem;
  font-weight: 600;
  text-align: left;
  box-shadow: none;
}

.ai-assistant-chips button:last-child {
  border-bottom: 0;
}

.ai-assistant-chips button:hover {
  background: var(--bg-soft);
  transform: translateX(3px);
  color: var(--text);
}

.ai-assistant-body {
  margin-top: 12px;
  margin-bottom: 12px;
  padding: 0;
  overflow-y: auto;
  min-height: 0;
  display: grid;
  gap: 8px;
}

.ai-assistant-msg {
  border: 1px solid var(--border);
  padding: 12px;
  background: var(--bg-elev);
  box-shadow: var(--shadow-sm);
}

.ai-assistant-msg header {
  font-size: 0.72rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.03em;
  margin-bottom: 4px;
  font-weight: 800;
}

.ai-assistant-msg p {
  font-size: 0.92rem;
  color: var(--text);
  line-height: 1.5;
}

.ai-assistant-msg.user {
  border-left: 3px solid var(--primary);
  background: var(--bg-soft);
}

.ai-assistant-results {
  margin-top: 10px;
  display: grid;
  gap: 7px;
}

.ai-assistant-result-link {
  border: 1px solid var(--border);
  background: var(--bg-elev);
  min-height: 42px;
  padding: 8px 10px;
  display: grid;
  grid-template-columns: 18px minmax(0, 1fr);
  gap: 8px;
  align-items: flex-start;
  color: var(--text);
}

.ai-assistant-result-link:hover {
  border-color: var(--primary);
  background: color-mix(in srgb, var(--primary) 14%, var(--overlay-soft));
}

.ai-assistant-result-index {
  font-size: 0.74rem;
  font-weight: 800;
  color: var(--primary);
  line-height: 1.3;
  padding-top: 2px;
}

.ai-assistant-result-text {
  min-width: 0;
}

.ai-assistant-result-text strong {
  display: block;
  font-size: 0.82rem;
  line-height: 1.35;
}

.ai-assistant-result-text small {
  display: block;
  margin-top: 2px;
  font-size: 0.72rem;
  color: var(--text-muted);
  line-height: 1.35;
}

.ai-assistant-input {
  border-top: 1px solid var(--border);
  padding-top: 12px;
  padding-bottom: 0;
  padding-left: 0;
  padding-right: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 8px;
  align-items: end;
  background: transparent;
}

.ai-assistant-input textarea {
  width: 100%;
  min-height: 56px;
  max-height: 110px;
  resize: vertical;
  border: 1px solid var(--border);
  background: var(--input-bg);
  color: var(--input-text);
  padding: 8px 10px;
  font-size: 0.92rem;
  outline: none;
}

.ai-assistant-input textarea:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 2px var(--focus-ring);
}

.ai-assistant-input button {
  min-height: 44px;
  border: 1px solid var(--border);
  padding: 0 14px;
  background: var(--bg-elev);
  color: var(--text);
  font-weight: 800;
  box-shadow: var(--shadow-sm);
}

.ai-assistant-input button:hover {
  background: var(--bg-soft);
}

.ai-assistant-input button:disabled {
  opacity: 0.65;
}

.ai-assistant-foot {
  border-top: 1px solid var(--border);
  margin-top: 12px;
  padding-top: 10px;
  padding-bottom: 0;
  padding-left: 0;
  padding-right: 0;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.77rem;
  color: var(--text-muted);
  background: transparent;
}

.ai-assistant-foot button {
  border: 1px solid var(--border);
  background: var(--overlay-soft);
  color: var(--text-muted);
  min-height: 28px;
  padding: 0 10px;
  font-size: 0.74rem;
  font-weight: 700;
}

.ai-assistant-foot button:hover {
  color: var(--danger);
}

/* ============================
   SCROLL-TO-TOP
   ============================ */
.scroll-top {
  position: fixed;
  bottom: 24px; right: 24px;
  width: 44px; height: 44px;
  background: var(--premium-gradient);
  color: #fff;
  border: none;
  cursor: pointer;
  box-shadow: var(--shadow-lg);
  display: flex; align-items: center; justify-content: center;
  font-size: 16px;
  opacity: 0;
  pointer-events: none;
  transition: 0.25s;
  z-index: 90;
}
.scroll-top.show { opacity: 1; pointer-events: auto; }
.scroll-top:hover { transform: translateY(-3px); filter: saturate(1.08); }

/* ============================
   OVERLAY (mobile drawers)
   ============================ */
.overlay {
  position: fixed;
  inset: 0;
  background: transparent;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s;
  z-index: 950;
}
.overlay.show { opacity: 1; pointer-events: auto; }

/* ============================
   RESPONSIVE
   ============================ */
@media (max-width: 1200px) {
  .question-list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  .course-question-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (max-width: 1100px) {
  .landing-nav {
    width: min(100% - 20px, 1180px);
    margin: 10px auto;
    position: sticky;
    top: 8px;
    justify-content: flex-start;
    align-items: center;
    min-height: 56px;
    gap: 8px;
    padding: 8px 10px;
    border: 1px solid var(--border);
    background:
      linear-gradient(132deg, color-mix(in srgb, var(--overlay-bg) 97%, #ffffff 3%), color-mix(in srgb, var(--overlay-soft) 93%, #ffffff 7%));
    box-shadow: var(--shadow-md);
    backdrop-filter: blur(18px) saturate(145%);
    -webkit-backdrop-filter: blur(18px) saturate(145%);
  }
  .landing-nav .auth-logo {
    font-size: 1.1rem;
    flex: 0 1 auto;
    min-width: 0;
    margin-right: auto;
  }
  .landing-menu-toggle {
    width: 42px;
    height: 42px;
    border: 1px solid var(--btn-surface-border);
    background: var(--btn-surface-bg);
    color: var(--btn-surface-text);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-sm);
    font-size: 1rem;
    order: 3;
    margin-left: 0;
  }
  .landing-menu-toggle:hover {
    border-color: var(--primary);
    color: var(--primary);
  }
  .landing-nav nav {
    position: absolute;
    top: calc(100% + 8px);
    left: 0;
    right: 0;
    width: 100%;
    display: none;
    grid-template-columns: 1fr;
    gap: 8px;
    padding: 12px;
    border: 1px solid var(--border);
    background: color-mix(in srgb, var(--overlay-bg) 98%, #ffffff 2%);
    box-shadow: var(--shadow-lg);
    z-index: 1300;
    backdrop-filter: none;
    -webkit-backdrop-filter: none;
    isolation: isolate;
  }
  .landing-nav.is-menu-open nav {
    display: grid;
  }
  .landing-nav nav > a:not(.btn),
  .course-menu-btn,
  .landing-nav .btn {
    min-height: 40px;
    padding: 0 12px;
    border: 1px solid var(--btn-surface-border);
    background: var(--btn-surface-bg);
    box-shadow: none;
    font-size: 0.88rem;
    white-space: nowrap;
  }
  .landing-theme-toggle {
    order: 2;
    width: 42px;
    min-width: 42px;
    min-height: 42px;
    box-shadow: var(--shadow-sm);
  }
  .landing-nav .ai-assistant-nav-btn {
    order: 1;
    margin-left: 0;
  }
  .landing-nav .btn {
    justify-content: center;
  }
  .course-menu {
    flex: 1 1 100%;
    width: 100%;
  }
  .course-menu-btn {
    width: 100%;
    justify-content: space-between;
  }
  .course-menu-panel {
    position: static;
    width: 100%;
    max-height: 280px;
    overflow-y: auto;
    margin-top: 8px;
    box-shadow: none;
    background: color-mix(in srgb, var(--overlay-bg) 98%, #ffffff 2%);
  }
}

@media (max-width: 900px) {
  .hamburger { display: block; }
  .sidebar { transform: translateX(-100%); }
  .sidebar.active { transform: translateX(0); }
  .container {
    margin-left: 0;
    width: 100%;
  }
  .footer { margin-left: 0; }
  .ai-assistant {
    right: 12px;
    bottom: 80px;
  }
  .ai-assistant-panel {
    right: 0;
    width: 100vw;
    height: calc(100dvh - var(--ai-assistant-top) - 10px);
    min-height: 360px;
  }
  .ai-assistant-panel-inner {
    padding: 14px;
  }
  .content { flex-direction: column; }
  .right { order: -1; }
  .desktop-icons { display: none; }
  .nav-search { display: none; }
  .nav-right .mobile-search,
  .nav-right .mobile-slider { display: block; }
  .home-hero { flex-direction: column; text-align: center; padding: 24px; }
  .hero-right img { width: 140px; }
  .assessment-hero,
  .assessment-layout,
  .session-topbar {
    grid-template-columns: 1fr;
    flex-direction: column;
  }
  .assessment-hero-metrics {
    min-width: 0;
    width: 100%;
  }
  .auth-page {
    grid-template-columns: 1fr;
    padding: 20px;
  }
  .auth-brand {
    min-height: auto;
    padding: 30px;
  }
  .content-grid,
  .contact-layout {
    grid-template-columns: 1fr;
  }
  .ad-layout {
    grid-template-columns: 1fr;
    padding-right: 0;
  }
  .pricing-grid {
    grid-template-columns: 1fr;
  }
  .portal-quick-grid,
  .portal-subject-grid,
  .portal-plan-grid,
  .portal-ad-grid,
  .course-ad-strip {
    grid-template-columns: 1fr;
  }
  .portal-section-head {
    align-items: flex-start;
    flex-direction: column;
  }
  .portal-search {
    grid-template-columns: 34px minmax(0, 1fr);
  }
  .portal-search button {
    grid-column: 1 / -1;
  }
  .paid-signin-strip {
    flex-direction: column;
    align-items: flex-start;
  }
  .seo-nav-grid {
    grid-template-columns: 1fr;
  }
  .seo-study-strip {
    align-items: flex-start;
    flex-direction: column;
  }
  .landing-nav {
    width: min(100% - 20px, 1180px);
    margin: 10px auto;
    position: sticky;
    top: 8px;
    align-items: center;
    flex-direction: row;
    justify-content: flex-start;
    gap: 8px;
    min-height: 56px;
    padding: 8px 10px;
    border: 1px solid var(--border);
    background:
      linear-gradient(132deg, color-mix(in srgb, var(--overlay-bg) 97%, #ffffff 3%), color-mix(in srgb, var(--overlay-soft) 93%, #ffffff 7%));
    box-shadow: var(--shadow-md);
    backdrop-filter: blur(18px);
    -webkit-backdrop-filter: blur(18px);
  }
  .landing-nav .auth-logo {
    font-size: 1.15rem;
    flex: 0 1 auto;
    min-width: 0;
    margin-right: auto;
  }
  .landing-menu-toggle {
    width: 42px;
    height: 42px;
    border: 1px solid var(--btn-surface-border);
    background: var(--btn-surface-bg);
    color: var(--btn-surface-text);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-sm);
    font-size: 1rem;
    order: 3;
    margin-left: 0;
  }
  .landing-menu-toggle:hover {
    border-color: var(--primary);
    color: var(--primary);
  }
  .landing-nav nav {
    position: absolute;
    top: calc(100% + 8px);
    left: 0;
    right: 0;
    width: 100%;
    display: none;
    grid-template-columns: 1fr;
    gap: 8px;
    padding: 12px;
    border: 1px solid var(--border);
    box-shadow: var(--shadow-lg);
    z-index: 1300;
    background: color-mix(in srgb, var(--overlay-bg) 97%, #ffffff 3%);
    backdrop-filter: none;
    -webkit-backdrop-filter: none;
    isolation: isolate;
  }
  .landing-nav.is-menu-open nav {
    display: grid;
  }
  .landing-nav nav > a:not(.btn),
  .course-menu-btn,
  .landing-nav .btn {
    min-height: 40px;
    padding: 0 12px;
    border: 1px solid var(--btn-surface-border);
    background: var(--btn-surface-bg);
    box-shadow: none;
    font-size: 0.88rem;
    white-space: nowrap;
  }
  .landing-theme-toggle {
    order: 2;
    width: 42px;
    min-width: 42px;
    min-height: 42px;
    box-shadow: var(--shadow-sm);
  }
  .landing-nav .ai-assistant-nav-btn {
    order: 1;
    width: 42px;
    height: 42px;
    min-width: 42px;
    min-height: 42px;
    box-shadow: var(--shadow-sm);
    margin-left: 0;
  }
  .landing-nav .btn {
    justify-content: center;
  }
  .course-menu {
    flex: 1 1 100%;
    width: 100%;
  }
  .course-menu-btn {
    width: 100%;
    justify-content: space-between;
  }
  .course-menu-panel {
    position: static;
    width: 100%;
    max-height: 280px;
    overflow-y: auto;
    margin-top: 8px;
    box-shadow: none;
    background: color-mix(in srgb, var(--overlay-bg) 98%, #ffffff 2%);
  }
  .course-strip {
    width: min(100% - 24px, 1180px);
    margin: 0 auto 14px;
    padding-bottom: 10px;
  }
  .landing-page {
    width: min(100% - 24px, 1180px);
    margin-bottom: 28px;
  }
  .content-hero,
  .portal-hero {
    padding: 26px 18px;
  }
  .content-hero h1,
  .portal-hero h1 {
    font-size: clamp(1.8rem, 8vw, 2.7rem);
  }
  .content-hero p,
  .portal-hero p {
    font-size: 0.96rem;
  }
  .landing-footer {
    width: min(100% - 24px, 1180px);
    gap: 12px;
  }
  .app-footer {
    width: auto;
    margin: 14px 12px 20px;
  }
  .landing-hero {
    grid-template-columns: 1fr;
    min-height: auto;
  }
  .landing-hero img {
    width: 180px;
  }
  .ad-rail {
    position: static;
    padding-right: 0;
    width: 100%;
    max-width: none;
  }
  .question-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: var(--grid-gap-md);
  }
  .card,
  .search-card {
    height: var(--q-card-h-tablet);
    min-height: var(--q-card-h-tablet);
  }
  .similar-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 12px;
  }
  .similar-item,
  .seo-nav-card {
    height: var(--similar-card-h-tablet);
    min-height: var(--similar-card-h-tablet);
  }
  .course-question-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 10px;
  }
  .course-question-card {
    height: var(--course-card-h-tablet);
    min-height: var(--course-card-h-tablet);
  }
}

@media (min-width: 901px) {
  .right-panel { display: none; }
}

@media (max-width: 600px) {
  .home-hero { padding: 20px; }
  .hero-left h1 { font-size: 22px; }
  .q-card { padding: 18px; }
  .question-list {
    grid-template-columns: 1fr;
    gap: 10px;
  }
  .card,
  .search-card {
    height: var(--q-card-h-mobile);
    min-height: var(--q-card-h-mobile);
    padding: 12px;
    }
  .card-meta,
  .search-meta {
    gap: 4px;
  }
  .card-text {
    font-size: 0.84rem;
    -webkit-line-clamp: 4;
  }
  .similar-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 10px;
  }
  .course-question-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 10px;
  }
  .course-question-card {
    height: var(--course-card-h-mobile);
    min-height: var(--course-card-h-mobile);
    padding: 10px;
  }
  .similar-item,
  .seo-nav-card {
    height: var(--similar-card-h-mobile);
    min-height: var(--similar-card-h-mobile);
    padding: 12px;
    }
  .seo-nav-card {
    height: auto;
    min-height: 44px;
    padding: 10px 12px;
  }
  .similar-item strong {
    font-size: 0.86rem;
    -webkit-line-clamp: 4;
  }
  .similar-item span {
    font-size: 11px;
  }
  .container { padding: 12px; }
  .ad-rail {
    width: 100%;
    max-width: none;
  }
  .ad-rail .ad-slot,
  .ad-rail .upgrade-card {
    width: 100%;
    max-width: none;
  }
  .assessment-hero { padding: 22px; }
  .assessment-hero h1 { font-size: 24px; }
  .assessment-hero-metrics,
  .assessment-form {
    grid-template-columns: 1fr;
  }
  .assessment-panel,
  .history-panel,
  .session-card {
    padding: 18px;
  }
  .auth-card {
    padding: 22px;
  }
  .content-hero {
    padding: 22px 16px;
  }
  .ai-assistant {
    right: 8px;
    bottom: 74px;
  }
  .ai-assistant-panel {
    right: 0;
    width: 100vw;
    height: calc(100dvh - var(--ai-assistant-top) - 8px);
    min-height: 300px;
  }
  .ai-assistant-panel-inner {
    padding: 12px;
  }
  .ai-assistant-chips {
    padding: 0;
  }
  .ai-assistant-input {
    grid-template-columns: 1fr;
  }
  .ai-assistant-input button {
    width: 100%;
  }
  .portal-hero {
    padding: 24px 14px;
  }
  .portal-search {
    min-height: 52px;
    padding: 6px;
  }
  .portal-search button {
    width: 100%;
  }
  .seo-options {
    grid-template-columns: 1fr;
  }
  .content-card {
    padding: 18px;
  }
  .landing-nav nav > a:not(.btn),
  .course-menu-btn,
  .landing-theme-toggle,
  .landing-nav .btn {
    font-size: 0.84rem;
    padding: 0 10px;
  }
  .course-strip a,
  .portal-chips a {
    font-size: 0.84rem;
    padding: 8px 11px;
  }
  .portal-tile,
  .portal-subject-grid a {
    min-height: auto;
    padding: 16px;
  }
  .paid-signin-strip {
    padding: 18px;
  }
  .pricing-grid {
    gap: 14px;
  }
  .landing-footer {
    align-items: center;
    flex-direction: column;
    text-align: center;
  }
  .app-footer a {
    width: 100%;
    justify-content: center;
  }
}

/* ============================
   READABILITY + NO-OVERLAY HARDENING
   ============================ */
.landing-nav,
.portal-nav,
.landing-nav nav,
.course-menu-panel,
.sidebar,
.right-panel,
.card,
.search-card,
.q-card,
.content-card,
.similar-item,
.course-question-card,
.seo-nav-card,
.upgrade-card,
.history-card,
.ad-slot,
.auth-card,
.app-modal-card,
.profile-card-mini,
.ai-assistant-panel,
.stat-box {
  backdrop-filter: none !important;
  -webkit-backdrop-filter: none !important;
}

.content-card,
.card,
.search-card,
.q-card,
.similar-item,
.course-question-card,
.seo-nav-card,
.upgrade-card,
.history-card,
.ad-slot,
.auth-card,
.app-modal-card,
.profile-card-mini,
.course-menu-panel,
.landing-nav nav,
.ai-assistant-panel,
.stat-box {
  background: var(--bg-elev);
  color: var(--text);
  border-color: var(--border);
}

[data-theme="dark"] .content-card,
[data-theme="dark"] .card,
[data-theme="dark"] .search-card,
[data-theme="dark"] .q-card,
[data-theme="dark"] .similar-item,
[data-theme="dark"] .course-question-card,
[data-theme="dark"] .seo-nav-card,
[data-theme="dark"] .upgrade-card,
[data-theme="dark"] .history-card,
[data-theme="dark"] .ad-slot,
[data-theme="dark"] .auth-card,
[data-theme="dark"] .app-modal-card,
[data-theme="dark"] .profile-card-mini,
[data-theme="dark"] .course-menu-panel,
[data-theme="dark"] .landing-nav nav,
[data-theme="dark"] .ai-assistant-panel,
[data-theme="dark"] .stat-box {
  background: var(--bg-elev);
}