/* ═══════════════════════════════════════════════════════════════════
   汉语大师 — Chinese Master
   Neo-Oriental Luxury Gaming Aesthetic
   ═══════════════════════════════════════════════════════════════════ */

/* ─── CSS Variables ──────────────────────────────────────────────── */
:root {
  /* Core palette */
  --bg-deep: #07060E;
  --bg-base: #0D0C18;
  --bg-card: #141322;
  --bg-card-hover: #1A192E;
  --bg-elevated: #1E1D33;
  
  /* Borders & surfaces */
  --border-subtle: rgba(255,255,255,0.06);
  --border-medium: rgba(255,255,255,0.10);
  --border-accent: rgba(255,255,255,0.15);
  --glass: rgba(20, 19, 34, 0.75);
  --glass-border: rgba(255,255,255,0.08);
  
  /* Accent colors — inspired by Chinese art */
  --jade: #3DD9A0;
  --jade-dim: #2A9B72;
  --jade-glow: rgba(61,217,160,0.15);
  --gold: #F0C850;
  --gold-dim: #C4A03A;
  --gold-glow: rgba(240,200,80,0.12);
  --crimson: #E85454;
  --crimson-dim: #B83A3A;
  --crimson-glow: rgba(232,84,84,0.12);
  --ink: #6B5CE7;
  --ink-dim: #4E41A8;
  --ink-glow: rgba(107,92,231,0.12);
  --lotus: #E07CC5;
  --lotus-dim: #A85A94;
  --cloud: #A8B4C8;
  --cloud-dim: #6B7588;
  
  /* Text */
  --text-primary: #EDE8D8;
  --text-secondary: #9B96A8;
  --text-muted: #5E5A6E;
  --text-ghost: #3A3748;
  
  /* Typography */
  --font-display: 'Noto Serif SC', 'Georgia', serif;
  --font-body: 'DM Sans', -apple-system, sans-serif;
  --font-mono: 'Space Mono', 'Menlo', monospace;
  
  /* Spacing */
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 14px;
  --space-lg: 20px;
  --space-xl: 28px;
  --space-2xl: 40px;
  
  /* Radius */
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-xl: 28px;
  --radius-full: 999px;
  
  /* Shadows */
  --shadow-sm: 0 2px 8px rgba(0,0,0,0.3);
  --shadow-md: 0 4px 20px rgba(0,0,0,0.4);
  --shadow-lg: 0 8px 40px rgba(0,0,0,0.5);
  --shadow-glow-jade: 0 0 30px rgba(61,217,160,0.15);
  --shadow-glow-gold: 0 0 30px rgba(240,200,80,0.12);
  --shadow-glow-crimson: 0 0 30px rgba(232,84,84,0.12);
  
  /* Transitions */
  --ease-out: cubic-bezier(0.22, 1, 0.36, 1);
  --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
  --duration-fast: 150ms;
  --duration-normal: 250ms;
  --duration-slow: 400ms;
}

/* ─── Reset & Base ───────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; -webkit-text-size-adjust: 100%; }
body {
  font-family: var(--font-body);
  background: var(--bg-deep);
  color: var(--text-primary);
  line-height: 1.5;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  -webkit-tap-highlight-color: transparent;
}
input, textarea, button { font-family: inherit; color: inherit; }
input:focus, textarea:focus { outline: none; }
a { color: var(--jade); text-decoration: none; }
a:hover { text-decoration: underline; }

/* Custom scrollbar */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border-medium); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--border-accent); }

/* ─── Background Texture ─────────────────────────────────────────── */
#root {
  min-height: 100vh;
  background: 
    radial-gradient(ellipse 80% 50% at 50% 0%, rgba(107,92,231,0.08) 0%, transparent 60%),
    radial-gradient(ellipse 60% 40% at 80% 100%, rgba(61,217,160,0.05) 0%, transparent 50%),
    radial-gradient(ellipse 50% 30% at 10% 60%, rgba(232,84,84,0.04) 0%, transparent 50%),
    linear-gradient(180deg, var(--bg-deep) 0%, var(--bg-base) 40%, var(--bg-deep) 100%);
  background-attachment: fixed;
}

/* Grain overlay */
#root::before {
  content: '';
  position: fixed;
  inset: 0;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.03'/%3E%3C/svg%3E");
  pointer-events: none;
  z-index: 0;
}

/* ─── Animations ─────────────────────────────────────────────────── */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(12px); }
  to { opacity: 1; transform: translateY(0); }
}
@keyframes slideUp {
  from { opacity: 0; transform: translateY(24px); }
  to { opacity: 1; transform: translateY(0); }
}
@keyframes scaleIn {
  from { opacity: 0; transform: scale(0.92); }
  to { opacity: 1; transform: scale(1); }
}
@keyframes pulse { 0%, 100% { transform: scale(1); } 50% { transform: scale(1.06); } }
@keyframes shake {
  0%, 100% { transform: translateX(0); }
  20% { transform: translateX(-10px); }
  40% { transform: translateX(10px); }
  60% { transform: translateX(-5px); }
  80% { transform: translateX(5px); }
}
@keyframes pop { 0% { transform: scale(1); } 25% { transform: scale(1.08); } 100% { transform: scale(1); } }
@keyframes glow {
  0%, 100% { box-shadow: 0 0 12px rgba(240,200,80,0.15); }
  50% { box-shadow: 0 0 28px rgba(240,200,80,0.3); }
}
@keyframes shimmer {
  0% { background-position: -200% 0; }
  100% { background-position: 200% 0; }
}
@keyframes floatSlow {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-6px); }
}
@keyframes borderPulse {
  0%, 100% { border-color: var(--border-subtle); }
  50% { border-color: var(--border-medium); }
}

.anim-fade { animation: fadeIn var(--duration-slow) var(--ease-out) both; }
.anim-slide { animation: slideUp var(--duration-slow) var(--ease-out) both; }
.anim-scale { animation: scaleIn var(--duration-normal) var(--ease-spring) both; }
.anim-shake { animation: shake 0.5s var(--ease-out); }
.anim-pop { animation: pop 0.6s var(--ease-spring); }
.anim-pulse { animation: pulse 1.5s ease-in-out infinite; }
.anim-glow { animation: glow 2.5s ease-in-out infinite; }
.anim-float { animation: floatSlow 3s ease-in-out infinite; }

/* Stagger children */
.stagger > *:nth-child(1) { animation-delay: 0ms; }
.stagger > *:nth-child(2) { animation-delay: 60ms; }
.stagger > *:nth-child(3) { animation-delay: 120ms; }
.stagger > *:nth-child(4) { animation-delay: 180ms; }
.stagger > *:nth-child(5) { animation-delay: 240ms; }
.stagger > *:nth-child(6) { animation-delay: 300ms; }

/* ─── Layout ─────────────────────────────────────────────────────── */
.container {
  max-width: 520px;
  margin: 0 auto;
  padding: var(--space-lg);
  position: relative;
  z-index: 1;
}

@media (min-width: 768px) {
  .container { max-width: 600px; padding: var(--space-xl); }
}

/* ─── Cards ──────────────────────────────────────────────────────── */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  transition: all var(--duration-normal) var(--ease-out);
}
.card:hover { border-color: var(--border-medium); }

.card-glass {
  background: var(--glass);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
}

.card-interactive {
  cursor: pointer;
  transition: all var(--duration-normal) var(--ease-out);
}
.card-interactive:hover {
  transform: translateY(-2px);
  border-color: var(--border-accent);
  box-shadow: var(--shadow-md);
}
.card-interactive:active {
  transform: translateY(0);
}

/* Question card */
.card-question {
  background: linear-gradient(135deg, var(--bg-card) 0%, var(--bg-elevated) 100%);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-xl);
  padding: var(--space-xl) var(--space-lg);
  text-align: center;
  position: relative;
  overflow: hidden;
}
.card-question::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--border-accent), transparent);
}

/* ─── Buttons ────────────────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: 12px 20px;
  border: none;
  border-radius: var(--radius-md);
  font-weight: 700;
  font-size: 14px;
  cursor: pointer;
  transition: all var(--duration-fast) var(--ease-out);
  min-height: 48px;
  position: relative;
  overflow: hidden;
}
.btn:active { transform: scale(0.97); }
.btn:disabled { opacity: 0.4; cursor: not-allowed; transform: none; }

.btn-primary {
  background: linear-gradient(135deg, var(--jade), var(--jade-dim));
  color: #fff;
  box-shadow: var(--shadow-glow-jade);
}
.btn-primary:hover:not(:disabled) { box-shadow: 0 0 40px rgba(61,217,160,0.25); }

.btn-gold {
  background: linear-gradient(135deg, var(--gold), var(--gold-dim));
  color: #1a1a2e;
  box-shadow: var(--shadow-glow-gold);
}

.btn-crimson {
  background: linear-gradient(135deg, var(--crimson), var(--crimson-dim));
  color: #fff;
  box-shadow: var(--shadow-glow-crimson);
}

.btn-ghost {
  background: transparent;
  border: 1px solid var(--border-medium);
  color: var(--text-secondary);
}
.btn-ghost:hover:not(:disabled) { border-color: var(--border-accent); color: var(--text-primary); }

.btn-full { width: 100%; padding: 16px 24px; font-size: 16px; border-radius: var(--radius-lg); }

.btn-launch {
  width: 100%;
  padding: 18px 24px;
  font-size: 17px;
  font-weight: 800;
  border-radius: var(--radius-lg);
  letter-spacing: 0.5px;
  position: relative;
}
.btn-launch::after {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.1), transparent);
  background-size: 200% 100%;
  animation: shimmer 3s ease-in-out infinite;
}

/* Choice buttons (QCM) */
.btn-choice {
  background: linear-gradient(135deg, var(--bg-card), var(--bg-elevated));
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 16px;
  color: var(--text-primary);
  font-size: 15px;
  cursor: pointer;
  transition: all var(--duration-fast) var(--ease-out);
  min-height: 52px;
  text-align: center;
}
.btn-choice:hover:not(:disabled) {
  transform: translateY(-2px) scale(1.02);
  border-color: var(--border-accent);
  box-shadow: var(--shadow-sm);
}
.btn-choice:active:not(:disabled) { transform: scale(0.98); }
.btn-choice.correct {
  background: linear-gradient(135deg, rgba(61,217,160,0.15), rgba(61,217,160,0.05));
  border-color: var(--jade);
  color: var(--jade);
}
.btn-choice.wrong {
  background: linear-gradient(135deg, rgba(232,84,84,0.15), rgba(232,84,84,0.05));
  border-color: var(--crimson);
  color: var(--crimson);
}
.btn-choice.eliminated {
  opacity: 0.15;
  text-decoration: line-through;
  cursor: default;
}

/* Selector buttons (config) */
.btn-select {
  flex: 1;
  padding: 14px 12px;
  background: var(--bg-card);
  border: 2px solid transparent;
  border-radius: var(--radius-md);
  cursor: pointer;
  text-align: center;
  transition: all var(--duration-fast) var(--ease-out);
  min-height: 52px;
}
.btn-select:hover { border-color: var(--border-medium); }
.btn-select.active-jade { background: var(--jade-glow); border-color: var(--jade); }
.btn-select.active-gold { background: var(--gold-glow); border-color: var(--gold); }
.btn-select.active-crimson { background: var(--crimson-glow); border-color: var(--crimson); }
.btn-select.active-ink { background: var(--ink-glow); border-color: var(--ink); }
.btn-select.active-lotus { background: rgba(224,124,197,0.08); border-color: var(--lotus); }
.btn-select.disabled { opacity: 0.25; cursor: not-allowed; }

/* Tag / pill buttons */
.btn-tag {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 6px 12px;
  background: transparent;
  border: 1px solid var(--border-medium);
  border-radius: var(--radius-full);
  font-size: 12px;
  cursor: pointer;
  transition: all var(--duration-fast) var(--ease-out);
  min-height: 32px;
  white-space: nowrap;
}
.btn-tag:hover:not(:disabled) { border-color: var(--border-accent); }
.btn-tag:disabled { opacity: 0.25; cursor: not-allowed; }
.btn-tag.active { background: var(--jade-glow); border-color: var(--jade); color: var(--jade); }

/* Mini action buttons */
.btn-mini {
  background: transparent;
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  padding: 4px 10px;
  font-size: 12px;
  cursor: pointer;
  transition: all var(--duration-fast) var(--ease-out);
  min-height: 30px;
}
.btn-mini:hover { border-color: var(--border-accent); }

/* Audio play button */
.btn-audio {
  width: 80px;
  height: 80px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--jade), var(--jade-dim));
  border: none;
  font-size: 36px;
  cursor: pointer;
  box-shadow: 0 4px 24px rgba(61,217,160,0.3);
  transition: all var(--duration-normal) var(--ease-spring);
  display: flex;
  align-items: center;
  justify-content: center;
  margin: var(--space-sm) auto;
}
.btn-audio:hover { transform: scale(1.08); box-shadow: 0 6px 32px rgba(61,217,160,0.4); }
.btn-audio:active { transform: scale(0.95); }

/* ─── Inputs ─────────────────────────────────────────────────────── */
.input {
  width: 100%;
  padding: 14px 16px;
  background: var(--bg-card);
  color: var(--text-primary);
  border: 1.5px solid var(--border-subtle);
  border-radius: var(--radius-md);
  font-size: 15px;
  transition: all var(--duration-fast) var(--ease-out);
}
.input:focus {
  border-color: var(--gold);
  box-shadow: 0 0 20px rgba(240,200,80,0.1);
}
.input::placeholder { color: var(--text-ghost); }

.input-write {
  padding: 16px 60px 16px 18px;
  font-size: 18px;
  border-width: 2px;
  border-radius: var(--radius-lg);
}
.input-write.judging { border-color: var(--ink); }
.input-write.correct { border-color: var(--jade); }
.input-write.wrong { border-color: var(--crimson); }

.textarea {
  width: 100%;
  padding: 14px 16px;
  background: var(--bg-deep);
  color: var(--text-primary);
  border: 1px solid var(--border-medium);
  border-radius: var(--radius-md);
  font-size: 14px;
  font-family: var(--font-mono);
  resize: vertical;
  min-height: 90px;
  transition: border-color var(--duration-fast);
}
.textarea:focus { border-color: var(--gold); }

/* ─── Progress bar ───────────────────────────────────────────────── */
.progress-track {
  height: 6px;
  background: var(--bg-elevated);
  border-radius: 3px;
  overflow: hidden;
}
.progress-fill {
  height: 100%;
  border-radius: 3px;
  transition: width 0.5s var(--ease-out);
}

.xp-bar .progress-fill { background: linear-gradient(90deg, var(--gold), var(--gold-dim)); }
.game-bar .progress-fill { background: linear-gradient(90deg, var(--jade), var(--gold)); }

/* ─── Typography ─────────────────────────────────────────────────── */
.font-display { font-family: var(--font-display); }
.font-mono { font-family: var(--font-mono); }
.text-xs { font-size: 11px; }
.text-sm { font-size: 13px; }
.text-md { font-size: 15px; }
.text-lg { font-size: 18px; }
.text-xl { font-size: 24px; }
.text-2xl { font-size: 32px; }
.text-3xl { font-size: 40px; }
.text-4xl { font-size: 52px; }
.fw-bold { font-weight: 700; }
.fw-black { font-weight: 900; }

.text-primary { color: var(--text-primary); }
.text-secondary { color: var(--text-secondary); }
.text-muted { color: var(--text-muted); }
.text-jade { color: var(--jade); }
.text-gold { color: var(--gold); }
.text-crimson { color: var(--crimson); }
.text-ink { color: var(--ink); }
.text-lotus { color: var(--lotus); }

/* Title gradient */
.title-gradient {
  font-family: var(--font-display);
  background: linear-gradient(135deg, var(--crimson), var(--gold) 50%, var(--jade));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: 4px;
}

/* Chinese character display */
.cn-char {
  font-family: var(--font-display);
  color: var(--crimson);
  cursor: pointer;
  transition: text-shadow var(--duration-normal);
}
.cn-char:hover { text-shadow: 0 0 20px rgba(232,84,84,0.3); }

.pinyin {
  font-family: var(--font-display);
  color: var(--gold);
  letter-spacing: 2px;
  cursor: pointer;
}
.pinyin:hover { text-shadow: 0 0 20px rgba(240,200,80,0.3); }

/* ─── Section title ──────────────────────────────────────────────── */
.section-title {
  font-size: 11px;
  font-weight: 700;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 2.5px;
  margin-bottom: var(--space-sm);
}

/* ─── Grids ──────────────────────────────────────────────────────── */
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: var(--space-sm); }
.grid-half { display: flex; gap: var(--space-md); }
.grid-half > * { flex: 1; }
.flex-row { display: flex; gap: var(--space-sm); }
.flex-center { display: flex; align-items: center; justify-content: center; }
.flex-between { display: flex; justify-content: space-between; align-items: center; }
.flex-wrap { flex-wrap: wrap; }
.gap-xs { gap: var(--space-xs); }
.gap-sm { gap: var(--space-sm); }
.gap-md { gap: var(--space-md); }
.gap-lg { gap: var(--space-lg); }
.text-center { text-align: center; }
.w-full { width: 100%; }
.mb-xs { margin-bottom: var(--space-xs); }
.mb-sm { margin-bottom: var(--space-sm); }
.mb-md { margin-bottom: var(--space-md); }
.mb-lg { margin-bottom: var(--space-lg); }
.mb-xl { margin-bottom: var(--space-xl); }
.mt-sm { margin-top: var(--space-sm); }
.mt-md { margin-top: var(--space-md); }

/* ─── SRS Level badge ────────────────────────────────────────────── */
.srs-badge {
  font-size: 11px;
  font-family: var(--font-mono);
  padding: 2px 10px;
  border-radius: var(--radius-full);
  white-space: nowrap;
}

.srs-bar {
  display: flex;
  height: 22px;
  border-radius: var(--radius-sm);
  overflow: hidden;
  background: var(--bg-card);
}
.srs-bar-segment {
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 9px;
  font-weight: 900;
  color: #000;
  min-width: 18px;
  transition: width var(--duration-slow);
}

/* ─── Score badge ────────────────────────────────────────────────── */
.score-ring {
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 900;
  font-family: var(--font-mono);
  color: #fff;
  flex-shrink: 0;
}
.score-ring-inner {
  border-radius: 50%;
  background: var(--bg-deep);
  display: flex;
  align-items: center;
  justify-content: center;
}

/* ─── Feedback card ──────────────────────────────────────────────── */
.feedback-card {
  background: linear-gradient(135deg, var(--bg-card), var(--bg-deep));
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  margin-top: var(--space-md);
  animation: slideUp var(--duration-slow) var(--ease-out);
  border: 2px solid transparent;
}
.feedback-card.good { border-color: var(--jade); }
.feedback-card.ok { border-color: var(--gold); }
.feedback-card.bad { border-color: var(--crimson); }

.feedback-badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 3px 10px;
  border-radius: var(--radius-full);
  font-size: 12px;
  border: 1px solid;
}

/* ─── Pinyin keyboard ────────────────────────────────────────────── */
.pinyin-kb {
  display: flex;
  gap: 4px;
  flex-wrap: wrap;
  justify-content: center;
  padding: var(--space-sm) 0;
}
.pinyin-kb button {
  width: 36px;
  height: 36px;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  color: var(--gold);
  font-size: 17px;
  cursor: pointer;
  font-family: var(--font-display);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--duration-fast) var(--ease-spring);
}
.pinyin-kb button:hover {
  background: var(--bg-elevated);
  transform: scale(1.15);
  border-color: var(--gold);
}
.pinyin-kb button:active { transform: scale(0.95); }

/* ─── Hint card ──────────────────────────────────────────────────── */
.hint-card {
  background: var(--bg-card);
  border: 1px solid rgba(224,124,197,0.2);
  border-radius: var(--radius-md);
  padding: var(--space-md);
  animation: fadeIn var(--duration-normal) var(--ease-out);
}
.hint-type {
  font-size: 10px;
  font-weight: 700;
  color: var(--lotus);
  text-transform: uppercase;
  letter-spacing: 1.5px;
}

/* ─── Vocab list item ────────────────────────────────────────────── */
.vocab-item {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: 12px 0;
  border-bottom: 1px solid var(--border-subtle);
  transition: background var(--duration-fast);
  flex-wrap: wrap;
}
.vocab-item:hover { background: rgba(255,255,255,0.02); }

/* ─── Alert / due banner ─────────────────────────────────────────── */
.alert-due {
  background: linear-gradient(135deg, rgba(232,84,84,0.08), rgba(232,84,84,0.03));
  border: 1px solid rgba(232,84,84,0.2);
  border-radius: var(--radius-md);
  padding: 12px var(--space-lg);
  color: var(--crimson);
  font-size: 14px;
  font-weight: 600;
}

/* ─── Stat card ──────────────────────────────────────────────────── */
.stat-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: var(--space-md);
  text-align: center;
  flex: 1;
}
.stat-value {
  font-size: 26px;
  font-weight: 900;
  font-family: var(--font-mono);
  line-height: 1.2;
}
.stat-label {
  font-size: 11px;
  color: var(--text-muted);
  margin-top: 2px;
}

/* ─── Game header ────────────────────────────────────────────────── */
.game-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--space-sm);
}
.game-stats {
  display: flex;
  gap: 14px;
  font-family: var(--font-mono);
  font-size: 13px;
}
.game-meta {
  display: flex;
  justify-content: space-between;
  font-size: 11px;
  color: var(--text-muted);
  margin-bottom: var(--space-md);
}

/* ─── Results grade ──────────────────────────────────────────────── */
.grade-display {
  font-size: 88px;
  font-weight: 900;
  font-family: var(--font-mono);
  line-height: 1;
  text-shadow: 0 0 60px currentColor;
}
.result-history {
  display: flex;
  gap: 4px;
  justify-content: center;
  flex-wrap: wrap;
  max-width: 380px;
}
.result-dot {
  width: 28px;
  height: 28px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 9px;
  font-weight: 700;
  font-family: var(--font-mono);
  border: 1px solid;
}

/* ─── Login screen ───────────────────────────────────────────────── */
.login-screen {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-lg);
}
.login-box { max-width: 420px; width: 100%; }

.profile-btn {
  width: 100%;
  padding: 16px 18px;
  background: var(--bg-deep);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 14px;
  font-size: 16px;
  font-weight: 600;
  color: var(--text-primary);
  transition: all var(--duration-fast) var(--ease-out);
  margin-bottom: var(--space-sm);
}
.profile-btn:hover {
  border-color: var(--jade);
  transform: translateY(-1px);
  box-shadow: var(--shadow-sm);
}

/* ─── Responsive tweaks ──────────────────────────────────────────── */
@media (max-width: 380px) {
  :root { --space-lg: 16px; --space-xl: 22px; }
  .container { padding: var(--space-md); }
  .title-gradient { font-size: 28px !important; letter-spacing: 2px; }
  .btn-audio { width: 68px; height: 68px; font-size: 30px; }
  .btn-choice { padding: 12px; font-size: 14px; min-height: 46px; }
  .pinyin-kb button { width: 32px; height: 32px; font-size: 15px; }
  .grade-display { font-size: 72px; }
}

@media (min-width: 768px) {
  .btn-choice { padding: 18px; font-size: 16px; }
  .card-question { padding: var(--space-2xl) var(--space-xl); }
  .btn-audio { width: 90px; height: 90px; font-size: 40px; }
}
</style>