/* ── Variables & Reset ──────────────────────────────────────────────── */
:root {
  --bg:       #0d0f14;
  --surface:  #161922;
  --surface2: #1e2230;
  --border:   #2a3040;
  --text:     #e8ecf4;
  --muted:    #7a8499;
  --accent:   #4f9eff;
  --accent2:  #a78bfa;
  --correct:  #34d399;
  --wrong:    #f87171;
  --warn:     #fbbf24;
  --radius:   14px;
  --shadow:   0 20px 60px rgba(0,0,0,.5);
  --font:     'Outfit', sans-serif;
  --font-serif: 'DM Serif Display', serif;
  --font-mono:  'DM Mono', monospace;
}

[data-theme="light"] {
  --bg:       #f4f6fb;
  --surface:  #ffffff;
  --surface2: #eef1f8;
  --border:   #d5dae8;
  --text:     #0d0f14;
  --muted:    #6b7589;
  --shadow:   0 20px 60px rgba(0,0,0,.12);
}

[data-contrast="high"] {
  --bg:      #000;
  --surface: #111;
  --text:    #fff;
  --muted:   #ccc;
  --border:  #555;
}

[data-motion="reduced"] * {
  animation: none !important;
  transition: none !important;
}

[data-dyslexia="on"] {
  --font: 'Courier New', monospace;
  letter-spacing: .04em;
  word-spacing: .1em;
  line-height: 1.8;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { font-size: 16px; }

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  min-height: 100dvh;
  transition: background .3s, color .3s;
  overflow-x: hidden;
}

/* ── App shell ──────────────────────────────────────────────────────── */
#app {
  max-width: 780px;
  margin: 0 auto;
  padding: 0 16px 80px;
  position: relative;
}

/* ── Header ─────────────────────────────────────────────────────────── */
#header {
  position: sticky;
  top: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 0;
  background: var(--bg);
  border-bottom: 1px solid var(--border);
  margin-bottom: 8px;
}

.logo {
  font-family: var(--font-serif);
  font-size: 1.25rem;
  cursor: pointer;
  letter-spacing: -.01em;
  color: var(--text);
}

nav { display: flex; gap: 8px; align-items: center; }

.nav-btn {
  background: var(--surface2);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 6px 14px;
  border-radius: 8px;
  font-family: var(--font);
  font-size: .85rem;
  cursor: pointer;
  transition: background .2s, border-color .2s;
}

.nav-btn:hover { background: var(--border); }

.icon-btn { padding: 6px 11px; font-size: 1rem; }

/* ── Accessibility Panel ─────────────────────────────────────────────── */
.panel {
  position: fixed;
  top: 68px;
  right: calc(50% - 390px + 16px);
  width: 240px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  z-index: 200;
  box-shadow: var(--shadow);
}

@media (max-width: 780px) { .panel { right: 16px; } }

.panel.hidden { display: none; }

.panel-title {
  font-weight: 600;
  font-size: .9rem;
  margin-bottom: 12px;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: .06em;
}

.a11y-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  padding: 8px 0;
  border-bottom: 1px solid var(--border);
  font-size: .9rem;
  color: var(--text);
  cursor: pointer;
}

.a11y-row:last-child { border-bottom: none; }

.a11y-row input[type="range"] { width: 90px; accent-color: var(--accent); }
.a11y-row input[type="checkbox"] { width: 18px; height: 18px; accent-color: var(--accent); }

/* ── Screens ─────────────────────────────────────────────────────────── */
.screen { display: none; }
.screen.active { display: block; animation: fadeUp .35s ease both; }

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(20px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ── Home Screen ─────────────────────────────────────────────────────── */
.hero {
  padding: 48px 0 36px;
  text-align: center;
}

.hero-badge {
  display: inline-block;
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 100px;
  padding: 4px 14px;
  font-size: .8rem;
  color: var(--muted);
  letter-spacing: .05em;
  text-transform: uppercase;
  margin-bottom: 20px;
}

.hero-title {
  font-family: var(--font-serif);
  font-size: clamp(2.8rem, 8vw, 4.5rem);
  line-height: 1;
  letter-spacing: -.03em;
  margin-bottom: 16px;
}

.hero-title em {
  font-style: italic;
  color: var(--accent);
}

.hero-sub {
  color: var(--muted);
  font-size: 1rem;
  max-width: 400px;
  margin: 0 auto 28px;
  line-height: 1.6;
}

.stat-row {
  display: flex;
  justify-content: center;
  gap: 16px;
  margin-bottom: 40px;
}

.stat-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 24px;
  text-align: center;
  min-width: 80px;
}

.stat-card span {
  display: block;
  font-family: var(--font-mono);
  font-size: 1.8rem;
  font-weight: 500;
  color: var(--accent);
}

.stat-card small {
  font-size: .75rem;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: .05em;
}

/* ── Mode cards ─────────────────────────────────────────────────────── */
.mode-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 14px;
  margin-bottom: 24px;
}

.mode-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px 20px 20px;
  text-align: left;
  cursor: pointer;
  transition: transform .2s, border-color .2s, box-shadow .2s;
  font-family: var(--font);
  color: var(--text);
  position: relative;
  overflow: hidden;
}

.mode-card::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, var(--accent)10, transparent 60%);
  opacity: 0;
  transition: opacity .2s;
}

.mode-card:hover {
  transform: translateY(-4px);
  border-color: var(--accent);
  box-shadow: 0 8px 30px rgba(79,158,255,.15);
}

.mode-card:hover::before { opacity: 1; }

.mode-icon { font-size: 2rem; margin-bottom: 12px; }
.mode-name { font-size: 1.05rem; font-weight: 600; margin-bottom: 6px; }
.mode-desc { font-size: .85rem; color: var(--muted); margin-bottom: 12px; line-height: 1.4; }
.mode-meta {
  font-size: .75rem;
  color: var(--accent);
  font-family: var(--font-mono);
  background: var(--surface2);
  display: inline-block;
  padding: 3px 9px;
  border-radius: 6px;
}

/* ── Filter row ─────────────────────────────────────────────────────── */
.filter-row {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 16px;
}

.filter-btn {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 6px 16px;
  font-family: var(--font);
  font-size: .85rem;
  color: var(--muted);
  cursor: pointer;
  transition: all .2s;
}

.filter-btn.active, .filter-btn:hover {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

/* ── Quiz header ─────────────────────────────────────────────────────── */
.quiz-header {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 16px 0 12px;
}

.back-btn {
  background: none;
  border: 1px solid var(--border);
  color: var(--muted);
  border-radius: 8px;
  padding: 7px 14px;
  cursor: pointer;
  font-size: .85rem;
  font-family: var(--font);
  transition: all .2s;
  white-space: nowrap;
}

.back-btn:hover { border-color: var(--text); color: var(--text); }

.quiz-progress {
  flex: 1;
  display: flex;
  align-items: center;
  gap: 10px;
}

.progress-bar {
  flex: 1;
  height: 5px;
  background: var(--surface2);
  border-radius: 10px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--accent), var(--accent2));
  border-radius: 10px;
  transition: width .4s ease;
}

#fcCount, #typeCount {
  font-size: .8rem;
  color: var(--muted);
  font-family: var(--font-mono);
  white-space: nowrap;
}

/* ── Timer ring ─────────────────────────────────────────────────────── */
.timer-ring {
  position: relative;
  width: 44px;
  height: 44px;
  flex-shrink: 0;
}

.timer-ring svg { transform: rotate(-90deg); }
.timer-ring circle.bg { fill: none; stroke: var(--surface2); stroke-width: 3; }
.timer-ring circle.fg {
  fill: none;
  stroke: var(--accent);
  stroke-width: 3;
  stroke-linecap: round;
  transition: stroke-dashoffset .9s linear, stroke .3s;
}

.timer-ring span {
  position: absolute;
  top: 50%; left: 50%;
  transform: translate(-50%, -50%);
  font-family: var(--font-mono);
  font-size: .75rem;
  font-weight: 500;
  color: var(--text);
}

/* ── 3D Card / Scene ─────────────────────────────────────────────────── */
.scene {
  perspective: 1200px;
  margin: 12px 0;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 32px 36px;
  min-height: 200px;
  display: flex;
  align-items: center;
  box-shadow: 0 4px 24px rgba(0,0,0,.2), 0 1px 0 var(--border) inset;
  transform-style: preserve-3d;
  transition: transform .6s cubic-bezier(.4,0,.2,1), box-shadow .3s;
  position: relative;
  overflow: hidden;
}

.card::after {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,.08), transparent);
}

.card:hover {
  transform: rotateX(3deg) rotateY(-2deg) translateY(-4px);
  box-shadow: 0 20px 50px rgba(0,0,0,.35), 0 1px 0 var(--border) inset;
}

.card-in {
  animation: cardSlide .4s cubic-bezier(.4,0,.2,1) both;
}

@keyframes cardSlide {
  from { opacity: 0; transform: translateX(40px) rotateY(-15deg); }
  to   { opacity: 1; transform: translateX(0) rotateY(0); }
}

.card-face {
  width: 100%;
}

.card-tag {
  font-size: .78rem;
  color: var(--accent);
  font-family: var(--font-mono);
  text-transform: uppercase;
  letter-spacing: .08em;
  margin-bottom: 16px;
  background: color-mix(in srgb, var(--accent) 12%, transparent);
  display: inline-block;
  padding: 4px 10px;
  border-radius: 6px;
}

.card-body {
  font-size: 1.05rem;
  line-height: 1.65;
  color: var(--text);
}

/* ── Choice buttons ─────────────────────────────────────────────────── */
.choices {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  margin: 8px 0;
}

@media (max-width: 500px) { .choices { grid-template-columns: 1fr; } }

.choice-btn {
  background: var(--surface);
  border: 1.5px solid var(--border);
  border-radius: 12px;
  padding: 14px 16px;
  text-align: left;
  font-family: var(--font);
  font-size: .9rem;
  color: var(--text);
  cursor: pointer;
  transition: all .2s;
  line-height: 1.4;
}

.choice-btn:hover:not(:disabled) {
  border-color: var(--accent);
  background: color-mix(in srgb, var(--accent) 8%, var(--surface));
  transform: translateY(-2px);
}

.choice-btn:disabled { cursor: default; }

.choice-btn.correct {
  border-color: var(--correct);
  background: color-mix(in srgb, var(--correct) 12%, var(--surface));
  color: var(--correct);
}

.choice-btn.wrong {
  border-color: var(--wrong);
  background: color-mix(in srgb, var(--wrong) 12%, var(--surface));
  color: var(--wrong);
}

/* ── Feedback bar ───────────────────────────────────────────────────── */
.feedback-bar {
  padding: 12px 18px;
  border-radius: 10px;
  font-size: .9rem;
  font-weight: 500;
  margin: 6px 0;
  animation: slideIn .25s ease;
}

@keyframes slideIn {
  from { opacity: 0; transform: translateY(8px); }
  to   { opacity: 1; transform: translateY(0); }
}

.feedback-bar.hidden { display: none; }

.fb-correct {
  background: color-mix(in srgb, var(--correct) 15%, var(--surface));
  border: 1px solid color-mix(in srgb, var(--correct) 40%, transparent);
  color: var(--correct);
}

.fb-wrong {
  background: color-mix(in srgb, var(--wrong) 15%, var(--surface));
  border: 1px solid color-mix(in srgb, var(--wrong) 40%, transparent);
  color: var(--wrong);
}

/* ── Type mode ──────────────────────────────────────────────────────── */
.type-area {
  display: flex;
  gap: 10px;
  margin: 10px 0;
}

.type-input {
  flex: 1;
  background: var(--surface);
  border: 1.5px solid var(--border);
  border-radius: 12px;
  padding: 14px 18px;
  font-family: var(--font);
  font-size: 1rem;
  color: var(--text);
  outline: none;
  transition: border-color .2s;
}

.type-input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent) 15%, transparent);
}

.submit-btn {
  background: var(--accent);
  border: none;
  border-radius: 12px;
  padding: 14px 22px;
  font-family: var(--font);
  font-size: .95rem;
  font-weight: 600;
  color: #fff;
  cursor: pointer;
  transition: opacity .2s, transform .15s;
}

.submit-btn:hover { opacity: .88; transform: translateY(-2px); }
.submit-btn:active { transform: translateY(0); }

.hint-row {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-top: 4px;
}

.hint-btn {
  background: none;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 6px 14px;
  font-size: .82rem;
  color: var(--muted);
  cursor: pointer;
  font-family: var(--font);
  transition: all .2s;
}

.hint-btn:hover { border-color: var(--warn); color: var(--warn); }

.hint-text {
  font-family: var(--font-mono);
  font-size: .9rem;
  color: var(--warn);
  letter-spacing: .05em;
}

/* ── Mastery overview ───────────────────────────────────────────────── */
.screen-header {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 20px 0 12px;
}

.screen-header h2 {
  font-family: var(--font-serif);
  font-size: 1.6rem;
}

.mastery-legend {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
  font-size: .8rem;
  color: var(--muted);
  margin-bottom: 20px;
}

.mastery-section-title {
  font-size: .78rem;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: .08em;
  font-weight: 600;
  margin: 20px 0 10px;
}

.mastery-list { padding-bottom: 20px; }

.mastery-row {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 14px 18px;
  margin-bottom: 8px;
  transition: border-color .2s;
}

.mastery-row.level-4 { border-color: color-mix(in srgb, var(--correct) 40%, var(--border)); }
.mastery-row.level-3 { border-color: color-mix(in srgb, var(--accent) 40%, var(--border)); }

.mastery-row-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 8px;
  margin-bottom: 8px;
}

.mastery-item-name {
  font-size: .9rem;
  font-weight: 500;
  flex: 1;
  line-height: 1.3;
}

.mastery-badge {
  font-size: .72rem;
  padding: 3px 10px;
  border-radius: 100px;
  font-family: var(--font-mono);
  white-space: nowrap;
  flex-shrink: 0;
}

.badge-0 { background: var(--surface2); color: var(--muted); }
.badge-1 { background: color-mix(in srgb, var(--wrong) 20%, transparent); color: var(--wrong); }
.badge-2 { background: color-mix(in srgb, var(--warn) 20%, transparent); color: var(--warn); }
.badge-3 { background: color-mix(in srgb, var(--accent) 20%, transparent); color: var(--accent); }
.badge-4 { background: color-mix(in srgb, var(--correct) 20%, transparent); color: var(--correct); }

.mastery-pips { display: flex; gap: 5px; margin-bottom: 6px; }

.pip {
  display: inline-block;
  width: 10px;
  height: 10px;
  border-radius: 3px;
}

/* pip colors by level */
.pip-0     { background: var(--surface2); border: 1px solid var(--border); }
.pip-1     { background: var(--wrong); }
.pip-2     { background: var(--warn); }
.pip-3     { background: var(--accent); }
.pip-4     { background: var(--correct); }
.pip-empty { background: var(--surface2); border: 1px solid var(--border); }

.mastery-stats {
  font-size: .76rem;
  color: var(--muted);
  font-family: var(--font-mono);
}

/* ── Results ─────────────────────────────────────────────────────────── */
.results-wrap {
  text-align: center;
  padding: 48px 20px 32px;
  max-width: 500px;
  margin: 0 auto;
}

.results-icon {
  font-size: 3.5rem;
  margin-bottom: 16px;
  animation: pop .5s cubic-bezier(.4,0,.2,1);
}

@keyframes pop {
  0%   { transform: scale(0); }
  70%  { transform: scale(1.15); }
  100% { transform: scale(1); }
}

.results-wrap h2 {
  font-family: var(--font-serif);
  font-size: 2rem;
  margin-bottom: 12px;
}

.score-display {
  font-family: var(--font-mono);
  font-size: 3.5rem;
  font-weight: 500;
  color: var(--accent);
  line-height: 1;
  margin-bottom: 8px;
}

.score-display small { font-size: 1.2rem; color: var(--muted); }

.results-msg {
  color: var(--muted);
  font-size: .95rem;
  margin-bottom: 24px;
}

.results-breakdown {
  text-align: left;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 8px 16px;
  margin-bottom: 24px;
  max-height: 240px;
  overflow-y: auto;
}

.bd-row {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  padding: 8px 0;
  border-bottom: 1px solid var(--border);
  font-size: .85rem;
}

.bd-row:last-child { border-bottom: none; }

.bd-icon { font-weight: 700; width: 18px; flex-shrink: 0; }
.bd-correct .bd-icon { color: var(--correct); }
.bd-wrong   .bd-icon { color: var(--wrong); }
.bd-name { color: var(--text); line-height: 1.4; }

.results-actions {
  display: flex;
  gap: 12px;
  justify-content: center;
}

.btn-primary {
  background: var(--accent);
  border: none;
  border-radius: 12px;
  padding: 13px 28px;
  font-family: var(--font);
  font-size: 1rem;
  font-weight: 600;
  color: #fff;
  cursor: pointer;
  transition: opacity .2s, transform .15s;
}

.btn-primary:hover { opacity: .88; transform: translateY(-2px); }

.btn-secondary {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 13px 28px;
  font-family: var(--font);
  font-size: 1rem;
  color: var(--text);
  cursor: pointer;
  transition: all .2s;
}

.btn-secondary:hover { border-color: var(--text); }

/* ── Scrollbar ───────────────────────────────────────────────────────── */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }

/* ── Responsive ─────────────────────────────────────────────────────── */
@media (max-width: 500px) {
  .card { padding: 24px 20px; }
  .stat-row { gap: 10px; }
  .stat-card { padding: 12px 16px; }
  .hero-title { font-size: 2.8rem; }
  .results-wrap { padding: 32px 0 24px; }
  .results-actions { flex-direction: column; }
}

/* ── Filter label in quiz header ─────────────────────────────────────── */
.filter-label {
  font-size: .72rem;
  font-family: var(--font-mono);
  color: var(--accent);
  background: color-mix(in srgb, var(--accent) 12%, transparent);
  border: 1px solid color-mix(in srgb, var(--accent) 25%, transparent);
  border-radius: 6px;
  padding: 3px 9px;
  white-space: nowrap;
  flex-shrink: 0;
}

/* ── Keyboard shortcut number on choice buttons ──────────────────────── */
.choice-key {
  display: inline-block;
  width: 20px;
  height: 20px;
  line-height: 20px;
  text-align: center;
  font-family: var(--font-mono);
  font-size: .7rem;
  font-weight: 600;
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 5px;
  margin-right: 10px;
  flex-shrink: 0;
  color: var(--muted);
  transition: background .15s, color .15s;
  vertical-align: middle;
}

.choice-btn:hover .choice-key,
.choice-btn:focus .choice-key {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

/* ── Keyboard hint line below choices ────────────────────────────────── */
.kbd-hint {
  font-size: .75rem;
  color: var(--muted);
  text-align: center;
  margin: 6px 0 2px;
  font-family: var(--font-mono);
}

.kbd-hint kbd {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: .7rem;
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 1px 5px;
  color: var(--muted);
  margin: 0 1px;
}

/* ── Filter row moved above mode grid ────────────────────────────────── */
/* (no style change needed — just ordering in HTML) */