/* =========================================================================
   FlashLumen — Lumen at midnight
   Dark-only by design. Warm-midnight canvas, signature amber accent,
   editorial layout, Fraunces + Geist + Geist Mono.
   ========================================================================= */

@import url('https://fonts.googleapis.com/css2?family=Fraunces:ital,opsz,wght@0,9..144,300..900;1,9..144,300..900&family=Geist:wght@300..700&family=Geist+Mono:wght@300..600&display=swap');

/* -------------------------------------------------------------------------
   Tokens
   ------------------------------------------------------------------------- */
:root {
  /* Canvas + surfaces */
  --canvas: #0f1217;
  --canvas-deep: #0a0c10;
  --surface: #171a21;
  --surface-2: #1d2129;
  --surface-3: #232830;
  --hairline: #292e38;
  --hairline-bright: #3a4150;

  /* Ink — text */
  --ink: #ece5d3;
  --ink-strong: #fbf6e8;
  --ink-dim: #9c968a;
  --ink-faint: #62605b;

  /* Lumen — signature amber */
  --lumen: #f6b352;
  --lumen-bright: #ffd28a;
  --lumen-deep: #c87f1f;
  --lumen-glow: 246, 179, 82;
  --lumen-on: #1a140a;        /* ink for text on amber bg */

  /* Semantic accents */
  --good:    #7fc28e;
  --hard:    #e0a657;
  --easy:    #92c8d8;
  --again:   #e07e6c;
  --danger:  #d77464;

  /* Type */
  --display: 'Fraunces', 'Cormorant Garamond', Georgia, serif;
  --sans:    'Geist', -apple-system, BlinkMacSystemFont, 'Helvetica Neue', sans-serif;
  --mono:    'Geist Mono', ui-monospace, 'JetBrains Mono', 'Cascadia Code', monospace;

  /* Shadows */
  --sh-soft:  0 1px 2px rgba(0,0,0,.35);
  --sh-card:  0 12px 30px rgba(0,0,0,.45), inset 0 1px 0 rgba(255,255,255,.03);
  --sh-hero:  0 30px 80px rgba(0,0,0,.55), inset 0 1px 0 rgba(255,255,255,.05);
  --sh-glow:  0 0 0 1px rgba(var(--lumen-glow), .35), 0 12px 40px rgba(var(--lumen-glow), .22);

  /* Motion */
  --ease-out:  cubic-bezier(.2,.7,.2,1);
  --ease-soft: cubic-bezier(.4,.0,.2,1);
}

/* -------------------------------------------------------------------------
   Reset
   ------------------------------------------------------------------------- */
*, *::before, *::after { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body, input, button, textarea, select { font: 16px/1.55 var(--sans); }
button { font-family: inherit; }
img, svg { display: block; max-width: 100%; }
a { color: var(--lumen); text-decoration: none; transition: color .2s var(--ease-soft); }
a:hover { color: var(--lumen-bright); }
hr {
  border: 0;
  border-top: 1px solid var(--hairline);
  margin: 2.5rem 0;
}
::selection { background: var(--lumen); color: var(--lumen-on); }

/* -------------------------------------------------------------------------
   Light theme — warm cream with the same lumen accent
   ------------------------------------------------------------------------- */
[data-theme="light"] {
  --canvas: #fbf8ee;
  --canvas-deep: #f1ecdb;
  --surface: #ffffff;
  --surface-2: #f8f4e6;
  --surface-3: #f0ebd8;
  --hairline: #e2dcc7;
  --hairline-bright: #cdc6ad;

  --ink: #2c2820;
  --ink-strong: #1a1812;
  --ink-dim: #5b574e;
  --ink-faint: #8b8775;

  --lumen: #cf8a25;
  --lumen-bright: #e8a23f;
  --lumen-deep: #9a6314;
  --lumen-glow: 207, 138, 37;
  --lumen-on: #fff8e8;

  --good:  #4f9b62;
  --hard:  #b97a1f;
  --easy:  #4f8aa1;
  --again: #c0573b;
  --danger: #c0573b;

  --sh-soft:  0 1px 2px rgba(80,60,20,.08);
  --sh-card:  0 6px 20px rgba(80,60,20,.06), inset 0 1px 0 rgba(255,255,255,.6);
  --sh-hero:  0 16px 50px rgba(80,60,20,.10), inset 0 1px 0 rgba(255,255,255,.7);
}
[data-theme="light"] body::before { opacity: .25; mix-blend-mode: multiply; }
[data-theme="light"] body::after  { opacity: .55; }
[data-theme="light"] .site-header { background: rgba(251, 248, 238, .82); }
[data-theme="light"] .site-footer { background: rgba(251, 248, 238, .85); }

/* -------------------------------------------------------------------------
   Body — viewport-locked layout. Header + footer stay fixed in view;
   sidebar and main scroll independently. No body-level scroll.
   ------------------------------------------------------------------------- */
html, body { height: 100%; overflow: hidden; }
html { background: var(--canvas-deep); }
body {
  background: var(--canvas);
  color: var(--ink);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  font-feature-settings: 'ss01', 'cv11';
  position: relative;
}
body::before {
  content: '';
  position: fixed; inset: 0;
  pointer-events: none;
  z-index: 1;
  /* SVG noise — tiny, repeating */
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='160' height='160'><filter id='n'><feTurbulence type='fractalNoise' baseFrequency='.9' numOctaves='2' stitchTiles='stitch'/><feColorMatrix values='0 0 0 0 0.93  0 0 0 0 0.89  0 0 0 0 0.82  0 0 0 .07 0'/></filter><rect width='100%' height='100%' filter='url(%23n)'/></svg>");
  mix-blend-mode: overlay;
  opacity: .55;
}
body::after {
  /* Soft amber glow at the top to suggest a single hanging lamp. */
  content: '';
  position: fixed;
  top: -200px; left: 50%;
  transform: translateX(-50%);
  width: 900px; height: 600px;
  background: radial-gradient(closest-side, rgba(var(--lumen-glow), .14), transparent 70%);
  pointer-events: none;
  z-index: 0;
}

/* -------------------------------------------------------------------------
   Typography
   ------------------------------------------------------------------------- */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--display);
  color: var(--ink-strong);
  font-weight: 460;
  letter-spacing: -0.02em;
  margin: 0 0 .8rem;
  font-feature-settings: 'ss01', 'liga';
}
h1 {
  font-size: clamp(2.4rem, 4.6vw, 3.6rem);
  line-height: 1.04;
  font-variation-settings: 'opsz' 144, 'SOFT' 50;
  letter-spacing: -0.03em;
}
h2 {
  font-size: 1.8rem;
  font-variation-settings: 'opsz' 72, 'SOFT' 50;
  margin-top: 2.5rem;
}
h5, .card-title {
  font-family: var(--display);
  font-size: 1.05rem;
  font-style: italic;
  font-weight: 400;
  font-variation-settings: 'opsz' 14;
  color: var(--ink-dim);
  margin: 0 0 1rem;
  letter-spacing: 0;
}
p { margin: 0 0 1rem; }
.text-muted, .text-muted * { color: var(--ink-dim); }
.small, small { font-size: .82rem; color: var(--ink-dim); }
.fs-4 { font-size: 1.4rem; line-height: 1.35; }

/* Eyebrow — a recurring all-caps mono micro-heading, used as a section tag. */
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: .5rem;
  font-family: var(--mono);
  font-size: .68rem;
  letter-spacing: .22em;
  text-transform: uppercase;
  color: var(--ink-faint);
}
.eyebrow::before {
  content: '';
  width: 22px; height: 1px;
  background: var(--lumen);
  display: inline-block;
}

/* -------------------------------------------------------------------------
   Layout
   ------------------------------------------------------------------------- */
.page {
  position: relative;
  z-index: 2;
  display: grid;
  grid-template-rows: auto 1fr auto;
  height: 100vh;
  overflow: hidden;
}

.shell {
  width: 100%;
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 2rem;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 30;
  backdrop-filter: blur(14px) saturate(120%);
  background: rgba(15, 18, 23, .72);
  border-bottom: 1px solid var(--hairline);
}
.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.1rem 0;
  gap: 1.5rem;
}
.brand {
  display: inline-flex;
  align-items: baseline;
  gap: .55rem;
  font-family: var(--display);
  font-size: 1.5rem;
  font-style: italic;
  font-weight: 500;
  font-variation-settings: 'opsz' 144;
  letter-spacing: -.01em;
  color: var(--ink-strong);
  text-decoration: none;
}
.brand:hover { color: var(--ink-strong); }
.brand__mark {
  display: inline-block;
  width: 12px; height: 12px;
  border-radius: 50%;
  background: var(--lumen);
  box-shadow: 0 0 14px rgba(var(--lumen-glow), .8);
  transform: translateY(-1px);
}
.brand__mark--quiet { box-shadow: 0 0 6px rgba(var(--lumen-glow), .35); }

.site-nav {
  display: flex;
  align-items: center;
  gap: 1.6rem;
}
.site-nav a {
  color: var(--ink-dim);
  font-size: .9rem;
  letter-spacing: .01em;
}
.site-nav a:hover { color: var(--ink-strong); }
.site-nav__user {
  font-family: var(--mono);
  font-size: .78rem;
  color: var(--ink-faint);
  letter-spacing: .02em;
}

/* Three-region body: optional sidebar (auth users only) + main content.
   Sidebar and main each get their own scroll context — body never scrolls. */
.page-body {
  display: grid;
  grid-template-columns: 260px 1fr;
  min-height: 0;
  overflow: hidden;
}
.page:not(:has(.sidebar)) .page-body { grid-template-columns: 1fr; }

main, .content {
  padding: 2.5rem 2.5rem 3rem;
  min-width: 0;
  overflow-y: auto;
  overflow-x: hidden;
}

/* Page-level section block with editorial margin */
.section { margin-top: 3rem; }
.section:first-child { margin-top: 0; }

/* -------------------------------------------------------------------------
   Sidebar — course / test / deck tree
   ------------------------------------------------------------------------- */
.sidebar {
  background: linear-gradient(180deg, var(--surface) 0%, var(--canvas-deep) 100%);
  border-right: 1px solid var(--hairline);
  padding: 2rem 1.25rem 3rem;
  overflow-y: auto;
  overflow-x: hidden;
  min-height: 0;
  position: relative;
  z-index: 2;
}
.sidebar__heading { margin-bottom: 1rem; }

.tree { list-style: none; margin: 0; padding: 0; }
.tree--nested {
  margin-left: 1rem;
  border-left: 1px solid var(--hairline);
  padding-left: .5rem;
  margin-top: .15rem;
}
.tree__node + .tree__node { margin-top: .15rem; }
.tree__row { display: flex; align-items: center; gap: .25rem; }
.tree__toggle {
  background: none;
  border: 0;
  color: var(--ink-faint);
  cursor: pointer;
  font-size: .8rem;
  padding: .15rem .25rem;
  width: 1.25rem;
  flex: 0 0 1.25rem;
}
.tree__toggle:hover { color: var(--lumen); }
.tree__label {
  flex: 1;
  padding: .25rem .35rem;
  border-radius: 4px;
  font-size: .88rem;
  color: var(--ink-dim);
  text-decoration: none;
  display: block;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
a.tree__label:hover { color: var(--lumen-bright); background: var(--surface-2); }
.tree__label--course { color: var(--ink); font-weight: 500; }
.tree__label--test {
  color: var(--lumen);
  font-style: italic;
  font-size: .82rem;
  font-family: var(--display);
}
.tree__label--deck { padding-left: .8rem; }

/* -------------------------------------------------------------------------
   Footer — breadcrumbs left, clock right
   ------------------------------------------------------------------------- */
.site-footer {
  background: rgba(15, 18, 23, .82);
  backdrop-filter: blur(14px) saturate(120%);
  border-top: 1px solid var(--hairline);
  position: relative;
  z-index: 30;
}
.site-footer__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  padding: .65rem 2rem;
  font-family: var(--mono);
  font-size: .72rem;
  letter-spacing: .08em;
  color: var(--ink-faint);
  min-height: 36px;
}
.site-footer__right {
  display: inline-flex;
  align-items: center;
  gap: 1rem;
}

/* Theme toggle — sun shows on dark, moon on light. Only one icon visible. */
.theme-toggle {
  background: transparent;
  border: 1px solid var(--hairline);
  border-radius: 50%;
  width: 26px;
  height: 26px;
  padding: 0;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: var(--ink-dim);
  transition: all .18s var(--ease-soft);
}
.theme-toggle:hover {
  color: var(--lumen);
  border-color: var(--lumen);
  box-shadow: 0 0 8px rgba(var(--lumen-glow), .25);
}
.theme-toggle__icon { font-size: .9rem; line-height: 1; }
[data-theme="lumen"] .theme-toggle__icon--moon { display: none; }
[data-theme="light"] .theme-toggle__icon--sun  { display: none; }

.crumbs { display: flex; align-items: center; gap: .35rem; flex-wrap: wrap; }
.crumbs__seg {
  color: var(--ink-faint);
  text-decoration: none;
  text-transform: lowercase;
}
.crumbs__seg:hover { color: var(--lumen); }
.crumbs__seg--current { color: var(--ink); }
.crumbs__seg--home { color: var(--ink-dim); }
.crumbs__sep { color: var(--ink-faint); opacity: .5; }

.clock { display: inline-flex; align-items: center; gap: .35rem; }
.clock__date { color: var(--ink-dim); }
.clock__sep { color: var(--ink-faint); opacity: .55; }
.clock__time { color: var(--lumen); }

/* Brand version badge (next to "FlashLumen" in the header) */
.brand__version {
  font-family: var(--mono);
  font-size: .65rem;
  color: var(--ink-faint);
  letter-spacing: .08em;
  margin-left: .15rem;
  font-style: normal;
  font-weight: 400;
  align-self: flex-end;
  padding-bottom: 4px;
}

/* -------------------------------------------------------------------------
   Page-load stagger animation
   ------------------------------------------------------------------------- */
@keyframes rise-in {
  from { opacity: 0; transform: translateY(14px); }
  to   { opacity: 1; transform: none; }
}
.content > * {
  animation: rise-in 700ms var(--ease-out) backwards;
}
.content > *:nth-child(1) { animation-delay: 60ms; }
.content > *:nth-child(2) { animation-delay: 140ms; }
.content > *:nth-child(3) { animation-delay: 220ms; }
.content > *:nth-child(4) { animation-delay: 300ms; }
.content > *:nth-child(5) { animation-delay: 380ms; }
main > *:nth-child(6) { animation-delay: 460ms; }

/* -------------------------------------------------------------------------
   Buttons
   ------------------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: .55rem;
  padding: .65rem 1.2rem;
  border-radius: 6px;
  border: 1px solid transparent;
  background: var(--surface-2);
  color: var(--ink);
  font: 500 .9rem/1 var(--sans);
  letter-spacing: .005em;
  cursor: pointer;
  transition: background .18s var(--ease-soft), border-color .18s var(--ease-soft), color .18s var(--ease-soft), transform .12s var(--ease-soft), box-shadow .25s var(--ease-soft);
  text-decoration: none;
}
.btn:disabled { opacity: .55; cursor: not-allowed; }
.btn:active:not(:disabled) { transform: translateY(1px); }
.btn:focus-visible { outline: 2px solid var(--lumen); outline-offset: 2px; }

.btn-sm { padding: .42rem .85rem; font-size: .82rem; }
.btn-lg { padding: .95rem 1.6rem; font-size: 1rem; }

.btn-primary {
  background: var(--lumen);
  color: var(--lumen-on);
  border-color: var(--lumen);
  box-shadow: 0 1px 0 rgba(255,255,255,.18) inset, 0 8px 24px rgba(var(--lumen-glow), .25);
}
.btn-primary:hover:not(:disabled) {
  background: var(--lumen-bright);
  border-color: var(--lumen-bright);
  box-shadow: 0 1px 0 rgba(255,255,255,.25) inset, 0 14px 36px rgba(var(--lumen-glow), .35);
}

.btn-outline-primary {
  background: transparent;
  color: var(--lumen);
  border-color: rgba(var(--lumen-glow), .55);
}
.btn-outline-primary:hover:not(:disabled) {
  background: rgba(var(--lumen-glow), .08);
  color: var(--lumen-bright);
  border-color: var(--lumen);
}

.btn-outline-secondary {
  background: transparent;
  color: var(--ink-dim);
  border-color: var(--hairline-bright);
}
.btn-outline-secondary:hover:not(:disabled) {
  background: var(--surface-2);
  color: var(--ink);
  border-color: var(--ink-faint);
}

.btn-outline-danger {
  background: transparent;
  color: var(--danger);
  border-color: rgba(215, 116, 100, .35);
}
.btn-outline-danger:hover:not(:disabled) {
  background: rgba(215, 116, 100, .08);
  color: #ec8b7c;
  border-color: var(--danger);
}

.btn-success {
  background: var(--good);
  color: #0a1410;
  border-color: var(--good);
  box-shadow: 0 1px 0 rgba(255,255,255,.18) inset, 0 8px 22px rgba(127, 194, 142, .22);
}
.btn-success:hover:not(:disabled) { background: #95d2a4; border-color: #95d2a4; }

.btn-link {
  background: none;
  color: var(--ink-dim);
  border: none;
  padding: .65rem .6rem;
  font-weight: 400;
}
.btn-link:hover:not(:disabled) { color: var(--lumen-bright); }

.w-100 { width: 100%; }

/* -------------------------------------------------------------------------
   Forms
   ------------------------------------------------------------------------- */
.form-control, input[type="email"], input[type="password"], input[type="text"], textarea {
  width: 100%;
  padding: .7rem .9rem;
  background: var(--surface);
  border: 1px solid var(--hairline);
  border-radius: 6px;
  color: var(--ink);
  font: 400 .95rem/1.4 var(--sans);
  transition: border-color .18s var(--ease-soft), background .18s var(--ease-soft), box-shadow .25s var(--ease-soft);
}
.form-control::placeholder { color: var(--ink-faint); }
.form-control:focus, input:focus, textarea:focus {
  outline: none;
  border-color: rgba(var(--lumen-glow), .65);
  background: var(--surface-2);
  box-shadow: 0 0 0 4px rgba(var(--lumen-glow), .10);
}
.form-label, label {
  display: block;
  font-family: var(--mono);
  font-size: .68rem;
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--ink-faint);
  margin-bottom: .4rem;
}
.form-group { margin-bottom: 1rem; }

.row {
  display: flex;
  flex-wrap: wrap;
  gap: var(--row-gap, 0);
  margin: 0;
}
.row.g-2 { gap: .6rem; --row-gap: .6rem; }
.row.g-3 { gap: 1rem; --row-gap: 1rem; }

.col,
[class^="col-"] { flex: 1 1 auto; min-width: 0; }
.col-md-1  { flex: 0 0 calc(8.333% - var(--row-gap, 0)); }
.col-md-2  { flex: 0 0 calc(16.666% - var(--row-gap, 0)); }
.col-md-3  { flex: 0 0 calc(25% - var(--row-gap, 0)); }
.col-md-4  { flex: 0 0 calc(33.333% - var(--row-gap, 0)); }
.col-md-5  { flex: 0 0 calc(41.666% - var(--row-gap, 0)); }
.col-md-6  { flex: 0 0 calc(50% - var(--row-gap, 0)); }
.col-md-8  { flex: 0 0 calc(66.666% - var(--row-gap, 0)); }
@media (max-width: 720px) {
  [class^="col-md-"] { flex: 1 1 100%; }
}

/* -------------------------------------------------------------------------
   Card (UI block, not flashcard)
   ------------------------------------------------------------------------- */
.card {
  position: relative;
  background: linear-gradient(180deg, var(--surface) 0%, var(--surface-2) 100%);
  border: 1px solid var(--hairline);
  border-radius: 10px;
  box-shadow: var(--sh-card);
  overflow: hidden;
}
.card::before {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: inherit;
  pointer-events: none;
  background:
    radial-gradient(800px 200px at 50% -50px, rgba(var(--lumen-glow), .06), transparent 60%);
}
.card-body { padding: 1.5rem 1.5rem 1.4rem; position: relative; }

/* -------------------------------------------------------------------------
   Alerts
   ------------------------------------------------------------------------- */
.alert {
  padding: .75rem 1rem;
  border-radius: 6px;
  font-size: .92rem;
  border: 1px solid var(--hairline);
  background: var(--surface);
}
.alert-danger {
  border-color: rgba(215, 116, 100, .35);
  background: rgba(215, 116, 100, .08);
  color: #f0b8ad;
}
.alert-warning {
  border-color: rgba(224, 166, 87, .35);
  background: rgba(224, 166, 87, .08);
  color: #f1c98a;
}
.alert ul { margin: 0; padding-left: 1.2rem; }

/* -------------------------------------------------------------------------
   Tables
   ------------------------------------------------------------------------- */
.table {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
  margin: 1.5rem 0;
  font-size: .94rem;
}
.table thead th {
  font-family: var(--mono);
  font-size: .68rem;
  letter-spacing: .2em;
  text-transform: uppercase;
  font-weight: 500;
  color: var(--ink-faint);
  text-align: left;
  padding: .85rem 1rem;
  border-bottom: 1px solid var(--hairline);
}
.table tbody td {
  padding: 1rem;
  border-bottom: 1px solid var(--hairline);
  color: var(--ink);
  vertical-align: middle;
}
.table tbody tr {
  transition: background .15s var(--ease-soft);
}
.table tbody tr:hover {
  background: var(--surface);
}
.table tbody tr:last-child td { border-bottom: 0; }
.table a { color: var(--ink-strong); border-bottom: 1px solid transparent; transition: border-color .15s var(--ease-soft); }
.table a:hover { color: var(--lumen-bright); border-bottom-color: rgba(var(--lumen-glow), .5); }

/* -------------------------------------------------------------------------
   List group (used on Deck detail for cards)
   ------------------------------------------------------------------------- */
.list-group {
  display: flex;
  flex-direction: column;
  gap: .55rem;
  margin: 1.5rem 0;
}
.list-group-item {
  background: var(--surface);
  border: 1px solid var(--hairline);
  border-radius: 8px;
  padding: 1rem 1.2rem;
  transition: border-color .18s var(--ease-soft), background .18s var(--ease-soft), transform .18s var(--ease-soft);
}
.list-group-item:hover {
  border-color: var(--hairline-bright);
  background: var(--surface-2);
  transform: translateX(2px);
}

/* -------------------------------------------------------------------------
   Helpers (minimal subset of bootstrap utility classes used in markup)
   ------------------------------------------------------------------------- */
.d-flex { display: flex; }
.d-inline-flex { display: inline-flex; }
.d-inline { display: inline; }
.flex-grow-1 { flex: 1 1 auto; min-width: 0; }
.align-items-center { align-items: center; }
.align-items-start { align-items: flex-start; }
.align-items-baseline { align-items: baseline; }
.justify-content-between { justify-content: space-between; }
.justify-content-center { justify-content: center; }
.text-end { text-align: right; }
.text-center { text-align: center; }
.gap-2 { gap: .55rem; }
.gap-3 { gap: 1rem; }
.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: .35rem; }
.mb-2 { margin-bottom: .65rem; }
.mb-3 { margin-bottom: 1rem; }
.mb-4 { margin-bottom: 1.6rem; }
.mt-1 { margin-top: .35rem; }
.mt-2 { margin-top: .65rem; }
.mt-3 { margin-top: 1rem; }
.me-2 { margin-right: .65rem; }
.ms-2 { margin-left: .65rem; }
.py-3 { padding-top: 1rem; padding-bottom: 1rem; }
.py-5 { padding-top: 3rem; padding-bottom: 3rem; }
.pb-2 { padding-bottom: .65rem; }
.fw-semibold { font-weight: 600; }
.border-bottom { border-bottom: 1px solid var(--hairline); }
.m-0 { margin: 0; }

/* Mono spans for IDs, timers, etc. */
.mono, .meta {
  font-family: var(--mono);
  font-size: .82rem;
  color: var(--ink-faint);
  letter-spacing: .02em;
}

/* -------------------------------------------------------------------------
   Auth pages — centered, spacious
   ------------------------------------------------------------------------- */
.auth-shell {
  max-width: 420px;
  margin: 4rem auto 0;
  padding: 0 1.5rem;
}
.auth-shell h1 {
  font-style: italic;
  font-variation-settings: 'opsz' 144, 'SOFT' 100;
  margin-bottom: 0;
}
.auth-shell .lede {
  color: var(--ink-dim);
  margin-top: .75rem;
  margin-bottom: 2rem;
  font-size: 1rem;
}
.auth-shell form > * + * { margin-top: 1rem; }
.auth-shell .form-actions {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-top: 1.6rem;
}

/* -------------------------------------------------------------------------
   Hero (Home)
   ------------------------------------------------------------------------- */
.hero { padding: 1rem 0 2rem; }
.hero h1 {
  font-style: italic;
  font-size: clamp(3rem, 7vw, 5.5rem);
  font-variation-settings: 'opsz' 144, 'SOFT' 100;
  letter-spacing: -.04em;
  line-height: 1;
  margin-bottom: 1.5rem;
}
.hero h1 .lumen-word {
  background: linear-gradient(180deg, var(--lumen-bright) 0%, var(--lumen) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  text-shadow: 0 0 30px rgba(var(--lumen-glow), .25);
}
.hero p {
  font-size: 1.1rem;
  color: var(--ink-dim);
  max-width: 38ch;
}
.hero .hero-actions {
  margin-top: 2rem;
  display: flex;
  gap: .8rem;
  flex-wrap: wrap;
}

/* -------------------------------------------------------------------------
   Course / Deck headers — editorial split
   ------------------------------------------------------------------------- */
.entity-header {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 2rem;
  align-items: end;
  padding-bottom: 1.6rem;
  margin-bottom: 2rem;
  border-bottom: 1px solid var(--hairline);
}
.entity-header__title { margin: 0; }
.entity-header__meta {
  display: flex;
  flex-direction: column;
  gap: .35rem;
  text-align: right;
  align-items: flex-end;
}
.entity-header__code {
  font-family: var(--mono);
  font-size: .78rem;
  letter-spacing: .15em;
  text-transform: uppercase;
  color: var(--lumen);
}
.entity-header__sub {
  font-family: var(--mono);
  font-size: .78rem;
  color: var(--ink-faint);
  letter-spacing: .04em;
}
.crumb {
  display: inline-flex;
  align-items: center;
  gap: .4rem;
  font-family: var(--mono);
  font-size: .75rem;
  letter-spacing: .15em;
  text-transform: uppercase;
  color: var(--ink-faint);
  margin-bottom: 1.5rem;
}
.crumb a { color: var(--ink-dim); }
.crumb a:hover { color: var(--lumen-bright); }

/* -------------------------------------------------------------------------
   Study page — the hero feature
   ------------------------------------------------------------------------- */
.study {
  max-width: 800px;
  margin: 0 auto;
  padding: 2rem 0 4rem;
}
/* tabindex="0" gives the container a focus outline by default — we use
   focus only to capture keys, not as a visible interaction state. */
.study:focus,
.study:focus-visible { outline: none; }
.study__progress {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 2rem;
}
.study__progress-text {
  font-family: var(--mono);
  font-size: .78rem;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--ink-faint);
}
.study__progress-bar {
  flex: 1;
  margin: 0 1.5rem;
  height: 1px;
  background: var(--hairline);
  position: relative;
  overflow: hidden;
}
.study__progress-bar::after {
  content: '';
  position: absolute;
  inset: 0 auto 0 0;
  width: var(--progress, 0%);
  background: linear-gradient(90deg, transparent, var(--lumen) 100%);
  transition: width .5s var(--ease-out);
  box-shadow: 0 0 8px rgba(var(--lumen-glow), .8);
}

.flashcard {
  position: relative;
  border: 1px solid var(--hairline);
  border-radius: 14px;
  background:
    linear-gradient(180deg, var(--surface-2) 0%, var(--surface) 100%);
  box-shadow: var(--sh-hero);
  padding: 3.5rem 3rem;
  min-height: 320px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  overflow: hidden;
  transition: box-shadow .4s var(--ease-out);
}
.flashcard.is-revealed {
  box-shadow: var(--sh-hero), 0 0 60px rgba(var(--lumen-glow), .12);
  border-color: rgba(var(--lumen-glow), .25);
}
.flashcard::before {
  content: '';
  position: absolute;
  top: 1rem; right: 1.25rem;
  width: 20px; height: 20px;
  border-top: 1px solid var(--hairline-bright);
  border-right: 1px solid var(--hairline-bright);
  opacity: .6;
}
.flashcard::after {
  content: '';
  position: absolute;
  bottom: 1rem; left: 1.25rem;
  width: 20px; height: 20px;
  border-bottom: 1px solid var(--hairline-bright);
  border-left: 1px solid var(--hairline-bright);
  opacity: .6;
}

.flashcard__label {
  font-family: var(--mono);
  font-size: .68rem;
  letter-spacing: .25em;
  text-transform: uppercase;
  color: var(--ink-faint);
  margin-bottom: 1.2rem;
  display: flex;
  align-items: center;
  gap: .5rem;
}
.flashcard__label::before {
  content: '';
  width: 22px; height: 1px;
  background: var(--lumen);
  opacity: .55;
}
.flashcard__label--answer { color: var(--lumen); }
.flashcard__label--answer::before { opacity: 1; box-shadow: 0 0 8px rgba(var(--lumen-glow), .6); }

.flashcard__text {
  font-family: var(--display);
  font-weight: 380;
  font-size: clamp(1.6rem, 3.2vw, 2.4rem);
  line-height: 1.25;
  color: var(--ink-strong);
  letter-spacing: -.015em;
  font-variation-settings: 'opsz' 144, 'SOFT' 50;
}
.flashcard__divider {
  height: 1px;
  background: var(--hairline);
  margin: 2rem 0;
  position: relative;
}
.flashcard__divider::before {
  content: '';
  position: absolute;
  top: -2px; left: 50%;
  transform: translateX(-50%);
  width: 5px; height: 5px;
  background: var(--lumen);
  border-radius: 50%;
  box-shadow: 0 0 10px rgba(var(--lumen-glow), .8);
  animation: rise-in 600ms var(--ease-out) backwards;
}

@keyframes reveal-answer {
  from { opacity: 0; transform: translateY(8px); }
  to   { opacity: 1; transform: none; }
}
.flashcard__answer { animation: reveal-answer 500ms var(--ease-out) backwards; }

/* Card ID in the bottom-right corner. Mono, faint, tucked inside the
   bottom-left bracket area so it doesn't fight the corner decoration. */
.flashcard__cardno {
  position: absolute;
  right: 1.25rem;
  bottom: 1rem;
  font-family: var(--mono);
  font-size: .72rem;
  letter-spacing: .12em;
  color: var(--ink-faint);
  pointer-events: none;
}

.study__reveal {
  width: 100%;
  margin-top: 2rem;
  padding: 1.1rem;
  font-size: 1rem;
  letter-spacing: .04em;
}

.rating-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: .8rem;
  margin-top: 2rem;
}
.rating-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: .35rem;
  padding: 1.2rem .5rem;
  background: var(--surface);
  border: 1px solid var(--hairline);
  border-radius: 8px;
  color: var(--ink);
  cursor: pointer;
  transition: all .18s var(--ease-soft);
  font-family: var(--sans);
  font-size: .95rem;
  letter-spacing: .02em;
}
.rating-btn:disabled { opacity: .55; cursor: not-allowed; }
.rating-btn:not(:disabled):hover {
  transform: translateY(-2px);
  background: var(--surface-2);
  border-color: var(--accent, var(--ink-faint));
  color: var(--accent, var(--ink-strong));
  box-shadow: 0 8px 24px rgba(0,0,0,.3);
}
.rating-btn__hotkey {
  font-family: var(--mono);
  font-size: .7rem;
  letter-spacing: .1em;
  color: var(--ink-faint);
}
.rating-btn:not(:disabled):hover .rating-btn__hotkey { color: var(--accent, var(--ink-dim)); }
.rating-btn--again  { --accent: var(--again); }
.rating-btn--hard   { --accent: var(--hard); }
.rating-btn--good   { --accent: var(--good); }
.rating-btn--easy   { --accent: var(--lumen-bright); background: linear-gradient(180deg, rgba(var(--lumen-glow), .10), transparent); }
.rating-btn--easy:not(:disabled):hover {
  border-color: var(--lumen);
  color: var(--lumen-bright);
  box-shadow: 0 8px 24px rgba(var(--lumen-glow), .25);
}

.complete {
  text-align: center;
  padding: 4rem 1rem 2rem;
}
.complete__mark {
  font-family: var(--display);
  font-style: italic;
  font-size: 4rem;
  color: var(--lumen);
  text-shadow: 0 0 30px rgba(var(--lumen-glow), .4);
  margin-bottom: 1rem;
  font-variation-settings: 'opsz' 144;
}
.complete h1 {
  font-style: italic;
  font-variation-settings: 'opsz' 144, 'SOFT' 100;
}
.complete .actions {
  margin-top: 2rem;
  display: flex;
  gap: .8rem;
  justify-content: center;
}

/* -------------------------------------------------------------------------
   Media gallery (CardEdit)
   ------------------------------------------------------------------------- */
.media-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  gap: 1rem;
}
.media-tile {
  margin: 0;
  border: 1px solid var(--hairline);
  border-radius: 8px;
  overflow: hidden;
  background: var(--canvas-deep);
  display: flex;
  flex-direction: column;
}
.media-tile img,
.media-tile video {
  width: 100%;
  height: 140px;
  object-fit: contain;
  background: #0a0c10;
  display: block;
}
.media-tile figcaption {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: .5rem .75rem;
  border-top: 1px solid var(--hairline);
  background: var(--surface);
}
.media-tile__loc {
  font-family: var(--mono);
  font-size: .68rem;
  text-transform: uppercase;
  letter-spacing: .15em;
  color: var(--ink-faint);
}

/* Inline-code media (SVG/HTML embedded directly in the card). */
.flashcard__inline-media {
  margin-bottom: 1.2rem;
  text-align: center;
}
.flashcard__inline-media svg {
  max-width: 100%;
  max-height: 320px;
  height: auto;
}

/* MC answer choices (pre-reveal, clickable) */
.answer-choices {
  display: flex;
  flex-direction: column;
  gap: .6rem;
  margin-top: 1.5rem;
}
.answer-choice {
  text-align: left;
  padding: .9rem 1.1rem;
  background: var(--surface);
  border: 1px solid var(--hairline);
  border-radius: 8px;
  color: var(--ink);
  font-family: var(--sans);
  font-size: 1rem;
  cursor: pointer;
  transition: all .15s var(--ease-soft);
}
.answer-choice:hover {
  background: var(--surface-2);
  border-color: rgba(var(--lumen-glow), .55);
  transform: translateX(2px);
}

/* MC answer reveal (post-reveal, read-only with correctness markers) */
.answer-list {
  display: flex;
  flex-direction: column;
  gap: .55rem;
  margin-top: 1rem;
}
.answer-item {
  padding: .75rem 1rem;
  background: var(--surface);
  border: 1px solid var(--hairline);
  border-left: 3px solid var(--hairline);
  border-radius: 6px;
  color: var(--ink-dim);
}
.answer-item__text { font-size: .98rem; }
.answer-item__explanation {
  margin-top: .45rem;
  font-size: .85rem;
  color: var(--ink-dim);
  font-style: italic;
}
.answer-item.is-correct {
  border-left-color: var(--good);
  background: linear-gradient(90deg, rgba(127, 194, 142, .10), transparent 40%);
  color: var(--ink);
}
.answer-item.is-correct .answer-item__text::before {
  content: '✓ ';
  color: var(--good);
  font-weight: 700;
  margin-right: .15rem;
}
.answer-item.is-wrong {
  border-left-color: var(--again);
  background: linear-gradient(90deg, rgba(224, 126, 108, .10), transparent 40%);
  color: var(--ink);
}
.answer-item.is-picked.is-wrong .answer-item__text::after {
  content: '  · your pick';
  font-family: var(--mono);
  font-size: .68rem;
  letter-spacing: .15em;
  text-transform: uppercase;
  color: var(--again);
  margin-left: .5rem;
}
.answer-item.is-picked.is-correct .answer-item__text::after {
  content: '  · your pick';
  font-family: var(--mono);
  font-size: .68rem;
  letter-spacing: .15em;
  text-transform: uppercase;
  color: var(--good);
  margin-left: .5rem;
}

/* Inline media on Study page (above question/answer) */
.flashcard__media {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: .75rem;
  margin-bottom: 1.2rem;
}
.flashcard__media img,
.flashcard__media video {
  width: 100%;
  max-height: 280px;
  object-fit: contain;
  border-radius: 6px;
  background: var(--canvas-deep);
  border: 1px solid var(--hairline);
}

/* Tiny indicator on DeckDetail card rows */
.media-pip {
  display: inline-flex;
  align-items: center;
  gap: .25rem;
  font-family: var(--mono);
  font-size: .7rem;
  color: var(--lumen);
  letter-spacing: .1em;
  text-transform: uppercase;
}
.media-pip::before {
  content: '';
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--lumen);
  box-shadow: 0 0 6px rgba(var(--lumen-glow), .8);
}

/* -------------------------------------------------------------------------
   Calendar (month view)
   ------------------------------------------------------------------------- */
.cal-grid {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  border: 1px solid var(--hairline);
  border-radius: 8px;
  overflow: hidden;
  background: var(--surface);
}
.cal-head {
  font-family: var(--mono);
  font-size: .68rem;
  letter-spacing: .2em;
  text-transform: uppercase;
  text-align: center;
  padding: .7rem 0;
  color: var(--ink-faint);
  background: var(--surface-2);
  border-bottom: 1px solid var(--hairline);
}
.cal-day {
  min-height: 110px;
  padding: .5rem .55rem;
  border-right: 1px solid var(--hairline);
  border-bottom: 1px solid var(--hairline);
  position: relative;
  cursor: pointer;
  transition: background .15s var(--ease-soft);
  display: flex;
  flex-direction: column;
  gap: .3rem;
}
.cal-day:hover { background: var(--surface-2); }
.cal-day:nth-child(7n + 7) { border-right: 0; }
.cal-day--other { background: var(--canvas-deep); color: var(--ink-faint); }
.cal-day--today .cal-day__num {
  color: var(--lumen);
  text-shadow: 0 0 8px rgba(var(--lumen-glow), .6);
}
.cal-day__num {
  font-family: var(--mono);
  font-size: .8rem;
  color: var(--ink-dim);
  letter-spacing: .03em;
}
.cal-event {
  display: flex;
  align-items: center;
  gap: .35rem;
  padding: .25rem .45rem;
  background: var(--surface-3);
  border-left: 2px solid var(--lumen);
  border-radius: 3px;
  font-size: .78rem;
  cursor: pointer;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.cal-event__time {
  font-family: var(--mono);
  font-size: .65rem;
  color: var(--ink-faint);
}
.cal-event--quiz   { border-left-color: var(--hard); }
.cal-event--exam   { border-left-color: var(--again); }
.cal-event--homework { border-left-color: var(--good); }
.cal-event--project { border-left-color: var(--easy); }

/* -------------------------------------------------------------------------
   Modal (Calendar event form)
   ------------------------------------------------------------------------- */
.modal-backdrop {
  position: fixed; inset: 0;
  background: rgba(0,0,0,.55);
  z-index: 50;
  animation: rise-in 200ms var(--ease-out) backwards;
}
.modal-panel {
  position: fixed;
  top: 50%; left: 50%;
  transform: translate(-50%, -50%);
  max-width: 540px;
  width: calc(100% - 2rem);
  max-height: 90vh;
  overflow-y: auto;
  z-index: 51;
  background: var(--surface);
  border: 1px solid var(--hairline);
  border-radius: 12px;
  box-shadow: var(--sh-hero);
  animation: rise-in 250ms var(--ease-out) backwards;
}
.modal-panel__inner { padding: 1.5rem; }
.modal-panel h2 {
  font-family: var(--display);
  font-style: italic;
  font-size: 1.6rem;
  font-variation-settings: 'opsz' 72;
}

/* -------------------------------------------------------------------------
   Reminder banner
   ------------------------------------------------------------------------- */
.reminder-banner {
  position: fixed;
  bottom: 1.5rem; right: 1.5rem;
  max-width: 360px;
  background: var(--surface-2);
  border: 1px solid var(--lumen);
  border-radius: 8px;
  padding: 1rem 1.2rem;
  box-shadow: 0 12px 36px rgba(0,0,0,.5), 0 0 24px rgba(var(--lumen-glow), .15);
  z-index: 100;
  animation: rise-in 400ms var(--ease-out) backwards;
}
.reminder-banner__label {
  font-family: var(--mono);
  font-size: .68rem;
  letter-spacing: .22em;
  text-transform: uppercase;
  color: var(--lumen);
  margin-bottom: .35rem;
}
.reminder-banner__title {
  font-family: var(--display);
  font-size: 1.1rem;
  font-style: italic;
  color: var(--ink-strong);
  margin-bottom: .25rem;
}
.reminder-banner__when {
  font-family: var(--mono);
  font-size: .78rem;
  color: var(--ink-dim);
  margin-bottom: .8rem;
}

/* -------------------------------------------------------------------------
   Misc
   ------------------------------------------------------------------------- */
h1:focus { outline: none; }
.valid.modified:not([type=checkbox]) {
  outline: 1px solid var(--good);
}
.invalid {
  outline: 1px solid var(--danger);
}
.validation-message { color: var(--danger); }

.blazor-error-boundary {
  background: var(--canvas-deep);
  border-top: 2px solid var(--danger);
  color: var(--ink);
  padding: 1rem 1.5rem;
  font-family: var(--mono);
  font-size: .85rem;
}
.blazor-error-boundary::after { content: 'An error has occurred — check the console.'; }

#blazor-error-ui {
  background: var(--canvas-deep);
  color: var(--ink);
  border-top: 1px solid var(--lumen);
  bottom: 0;
  box-sizing: border-box;
  display: none;
  left: 0;
  padding: .8rem 1.25rem;
  position: fixed;
  width: 100%;
  z-index: 1000;
  font-family: var(--mono);
  font-size: .85rem;
  box-shadow: 0 -10px 30px rgba(0,0,0,.5);
}
#blazor-error-ui .dismiss { cursor: pointer; position: absolute; right: 1rem; top: .55rem; color: var(--lumen); }
#blazor-error-ui .reload  { color: var(--lumen); margin-left: .5rem; }