/* Vidyudabhi exam-engine design system — professional CBT look.
   Deliberately distinct from the marketing site's navy/champagne palette:
   this is meant to feel like examination software, not a landing page. */
:root {
  --ex-primary: #2C3E8C;
  --ex-primary-dark: #1F2C66;
  --ex-btn: #2C3E8C;
  --ex-btn-hover: #1F2C66;
  --ex-on-primary: #FFFFFF;
  --ex-primary-light: #EEF0FA;
  --ex-bg: #F5F6F8;
  --ex-surface: #FFFFFF;
  --ex-text: #14171F;
  --ex-text-secondary: #5B6270;
  --ex-text-muted: #9198A6;
  --ex-border: #E2E4EA;
  --ex-grey: #D8DAE1;
  --ex-grey-text: #6B7280;
  --ex-red: #D64545;
  --ex-red-bg: #FDECEC;
  --ex-green: #1B8A5A;
  --ex-green-bg: #E8F6EF;
  --ex-green-text: #146C46;
  --ex-purple: #7C3AED;
  --ex-purple-bg: #F1EAFD;
  --ex-amber: #B7791F;
  --ex-amber-bg: #FEF3E2;
  --ex-amber-text: #7A5A22;
  --ex-radius-sm: 8px;
  --ex-radius: 12px;
  --ex-radius-lg: 16px;
}

/* Dark theme -- "premium EdTech / professional CBT" palette, not just an
   inverted light theme. Multiple dark surfaces (bg / bg-secondary /
   surface / surface-elevated / input-bg) create depth without relying on
   heavy shadows, per the design brief -- never pure #000. See
   assets/theme.js for how data-theme gets set. */
[data-theme="dark"] {
  --ex-primary: #3B82F6;
  --ex-primary-dark: #60A5FA;
  --ex-btn: #2563EB;
  --ex-btn-hover: #1D4ED8;
  --ex-primary-light: #16233D;
  --ex-bg: #080B12;
  --ex-bg-secondary: #0D111A;
  --ex-surface: #111722;
  --ex-surface-elevated: #151C28;
  --ex-input-bg: #0F1520;
  --ex-text: #F5F7FA;
  --ex-text-secondary: #AAB4C3;
  --ex-text-muted: #8795A9;
  --ex-border: #273142;
  --ex-border-active: rgba(59, 130, 246, 0.6);
  --ex-grey: #303A4A;
  --ex-grey-text: #AAB4C3;
  --ex-red: #F0716A;
  --ex-red-bg: #2E1A1D;
  --ex-green: #34D399;
  --ex-green-bg: #14261F;
  --ex-purple: #8B5CF6;
  --ex-purple-bg: #221A3D;
  --ex-amber: #F0B75E;
  --ex-amber-bg: #2E2412;
  --ex-amber-text: #F0B75E;
  --ex-shadow: 0 10px 30px rgba(0, 0, 0, 0.25);
  --ex-scrollbar-track: var(--ex-bg-secondary);
  --ex-scrollbar-thumb: #303A4A;
  --ex-scrollbar-thumb-hover: #465268;
}

/* Light theme's surfaces don't have secondary/elevated/input distinctions
   in the original palette -- alias them to the two shades that already
   exist so components written against the new tokens still work in light
   mode without a separate light redesign. */
:root {
  --ex-bg-secondary: var(--ex-bg);
  --ex-surface-elevated: var(--ex-surface);
  --ex-input-bg: var(--ex-surface);
  --ex-border-active: var(--ex-primary);
  --ex-shadow: 0 10px 30px rgba(20, 23, 31, 0.08);
  --ex-scrollbar-track: var(--ex-bg);
  --ex-scrollbar-thumb: var(--ex-grey);
  --ex-scrollbar-thumb-hover: var(--ex-text-muted);
}

* { box-sizing: border-box; }

/* Custom scrollbar -- subtle, matches whichever theme is active. */
.exam-app { scrollbar-color: var(--ex-scrollbar-thumb) var(--ex-scrollbar-track); scrollbar-width: thin; }
.exam-app ::-webkit-scrollbar { width: 10px; height: 10px; }
.exam-app ::-webkit-scrollbar-track { background: var(--ex-scrollbar-track); }
.exam-app ::-webkit-scrollbar-thumb { background: var(--ex-scrollbar-thumb); border-radius: 999px; border: 2px solid var(--ex-scrollbar-track); }
.exam-app ::-webkit-scrollbar-thumb:hover { background: var(--ex-scrollbar-thumb-hover); }

/* Accessibility: a visible focus ring for keyboard users on every
   interactive element -- including custom divs given role="button"/
   "radio" and tabindex, which get no default browser outline at all.
   :focus-visible (not plain :focus) so a mouse click doesn't show a ring
   that's only meant for keyboard/AT navigation. */
.exam-app :focus-visible {
  outline: 3px solid var(--ex-primary);
  outline-offset: 2px;
}
.exam-app [role="button"], .exam-app [role="radio"] { cursor: pointer; }
.visually-hidden {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0;
}

body.exam-app {
  margin: 0;
  background: var(--ex-bg);
  color: var(--ex-text);
  font-family: 'Inter', 'Noto Sans Devanagari', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}
.exam-app a { color: inherit; text-decoration: none; }
.exam-wrap { max-width: 1180px; margin: 0 auto; padding: 0 20px; }

/* Top bar shared across exam-flow pages -- sticky with a subtle backdrop
   blur so it stays lightweight rather than a solid heavy strip. */
.exam-topbar {
  background: var(--ex-surface);
  background: color-mix(in srgb, var(--ex-surface) 92%, transparent);
  backdrop-filter: blur(10px); -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--ex-border);
  padding: 14px 20px; display: flex; align-items: center; justify-content: space-between;
  position: sticky; top: 0; z-index: 30;
}
.exam-brand { display: flex; align-items: center; gap: 9px; font-weight: 800; font-size: 16.5px; color: var(--ex-text); }
.exam-brand-mark { width: 26px; height: 26px; border-radius: 7px; background: var(--ex-primary); display: flex; align-items: center; justify-content: center; }
.exam-brand-mark svg { width: 14px; height: 14px; }

/* Buttons -- comfortable touch targets (min 44px tall), quick 170ms
   transitions only, no scaling/glow. */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 6px;
  font-weight: 650; font-size: 14px; padding: 12px 22px; min-height: 44px;
  border-radius: var(--ex-radius-sm); border: none; cursor: pointer; font-family: inherit;
  transition: background-color .17s ease, border-color .17s ease, transform .17s ease;
}
.btn-primary { background: var(--ex-btn); color: #fff; }
.btn-primary:hover { background: var(--ex-btn-hover); }
.exam-app a.btn-primary, .exam-app a.btn-primary:hover, .exam-app a.btn-danger, .exam-app .btn-primary, .exam-app .btn-danger { color: #fff; }
.btn-secondary { background: var(--ex-surface-elevated); color: var(--ex-text); border: 1px solid var(--ex-border); }
.btn-secondary:hover { border-color: var(--ex-primary); background: var(--ex-surface); }
.btn-danger { background: var(--ex-red); color: #fff; }
.btn:disabled { opacity: 0.45; cursor: not-allowed; }
.btn-sm { padding: 9px 15px; font-size: 13px; min-height: 36px; }

/* Badges */
.tag { display: inline-flex; align-items: center; gap: 4px; padding: 3px 10px; border-radius: 999px; font-size: 11px; font-weight: 700; letter-spacing: 0.01em; }
.tag-official { background: var(--ex-green-bg); color: var(--ex-green-text, var(--ex-green)); }
.tag-memory { background: var(--ex-amber-bg); color: var(--ex-amber-text); }
.tag-practice { background: var(--ex-primary-light); color: var(--ex-primary); }
.tag-review { background: var(--ex-red-bg); color: var(--ex-red); }

/* Cards */
.ex-card { background: var(--ex-surface); border: 1px solid var(--ex-border); border-radius: var(--ex-radius-lg); }
a.ex-card, .ex-card.hoverable {
  display: block; transition: border-color .17s ease, transform .17s ease, box-shadow .17s ease;
}
a.ex-card:hover, .ex-card.hoverable:hover {
  border-color: var(--ex-border-active); transform: translateY(-2px); box-shadow: var(--ex-shadow);
}

/* Status legend colors, reused by palette */
.status-dot { display: inline-block; width: 10px; height: 10px; border-radius: 3px; }
.status-dot.not-visited { background: var(--ex-grey); }
.status-dot.not-answered { background: var(--ex-red); border-radius: 50%; }
.status-dot.answered { background: var(--ex-green); border-radius: 50%; }
.status-dot.marked { background: var(--ex-purple); border-radius: 50%; }
.status-dot.marked-answered { background: linear-gradient(135deg, var(--ex-green) 50%, var(--ex-purple) 50%); border-radius: 50%; }

/* Skeleton loading -- theme-aware so a loading state never flashes a
   plain white block on a dark page. */
.skeleton {
  background: linear-gradient(90deg, var(--ex-surface) 25%, var(--ex-surface-elevated) 37%, var(--ex-surface) 63%);
  background-size: 400% 100%; animation: skeleton-loading 1.4s ease infinite; border-radius: 8px;
}
@keyframes skeleton-loading { 0% { background-position: 100% 50%; } 100% { background-position: 0 50%; } }

.status-toast {
  position: fixed; bottom: 20px; left: 50%; transform: translateX(-50%);
  background: var(--ex-surface-elevated); color: var(--ex-text); border: 1px solid var(--ex-border);
  padding: 10px 18px; border-radius: 999px; box-shadow: var(--ex-shadow);
  font-size: 13px; font-weight: 600; opacity: 0; pointer-events: none; transition: opacity .2s;
  z-index: 100;
}
.status-toast.show { opacity: 1; }

/* Empty / error state pattern (spec §43/45) -- reused wherever a page has
   nothing to show instead of a blank area. */
.ex-empty-state {
  text-align: center; padding: 60px 24px; color: var(--ex-text-secondary);
}
.ex-empty-state .icon { color: var(--ex-text-muted); margin-bottom: 14px; }
.ex-empty-state h3 { color: var(--ex-text); font-size: 16px; font-weight: 700; margin: 0 0 6px; }
.ex-empty-state p { font-size: 13.5px; margin: 0 0 16px; }

/* Active chips / selected pills: white text on a button-blue that passes contrast in both themes */
.exam-app .filter-chip.active { background: var(--ex-btn); border-color: var(--ex-btn); color: #fff; }

/* Figures and diagram options (assets/qmedia.js). White plate so line art
   drawn for a light background stays readable in dark theme. */
.q-figure { margin: 14px 0 18px; display: flex; flex-wrap: wrap; align-items: center; gap: 10px; }
.q-figure .q-img, .opt-img { background: #fff; border-radius: 10px; padding: 8px; max-width: 100%; height: auto; display: block; }
.q-figure .q-img { max-height: 420px; width: auto; border: 1px solid var(--ex-border); }
.q-step { margin: 0; }
.q-step .q-img { max-height: 180px; }
.q-arrow { font-size: 22px; color: var(--ex-text-secondary); }
.opt-img { max-height: 200px; width: auto; }
.opt-cap { display: block; margin-top: 6px; font-size: 13px; color: var(--ex-text-secondary); }
@media (max-width: 640px) { .q-figure .q-img { max-height: 300px; } .opt-img { max-height: 150px; } }