:root {
    --bg: #070707;
    --surface: #0e0b0b;
    --border: rgba(255, 255, 255, .18);
    --accent: #ffffff;
    --accent-dim: rgba(255, 255, 255, .45);
    --text: #ffffff;
    --muted: #bbbaaa;
    --correct: #6ee787;
    --wrong: #ff4d6d;
    --wrong-dim: #3d1520;
    --correct-dim: rgba(110, 231, 135, .12);
    --selected: rgba(255, 255, 255, .10);
    --selected-border: rgba(255, 255, 255, .55);
    --radius: 8px;
  }

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

  body {
    background: var(--bg);
    color: var(--text);
    font-family: 'Shippori Mincho B1', monospace;
    font-weight: 500;
    min-height: 100vh;
  }

  header {
    border-bottom: 1px solid var(--border);
    padding: 24px 40px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    position: sticky;
    top: 0;
    background: var(--bg);
    z-index: 100;
  }

  header h1 {
    font-size: 1.1rem;
    font-weight: 500;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--accent);
  }

  #scoreboard {
    font-family: 'Shippori Mincho B1', monospace;
    font-size: 0.8rem;
    color: var(--muted);
  }

  #scoreboard span { color: var(--accent); font-weight: 500; }

  .progress-bar-wrap { height: 3px; background: var(--border); width: 100%; }
  .progress-bar-fill { height: 3px; background: var(--accent); transition: width 0.4s ease; width: 0%; }

  main {
    max-width: 1040px;
    margin: 0 auto;
    padding: 48px 24px 120px;
  }

  .mode-toggle { display: flex; gap: 12px; margin-bottom: 40px; }

  .mode-btn {
    background: var(--surface);
    border: 1px solid var(--border);
    color: var(--muted);
    font-family: 'Shippori Mincho B1', monospace;
    font-size: 0.75rem;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    padding: 8px 18px;
    border-radius: var(--radius);
    cursor: pointer;
    transition: all 0.2s;
  }
  .mode-btn.active { background: var(--accent); color: #000; border-color: var(--accent); font-weight: 500; }
  .mode-btn:hover:not(.active) { border-color: var(--accent-dim); color: var(--text); }

  #quiz-mode { display: block; }
  #study-mode { display: none; }

  .question-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 32px;
    margin-bottom: 32px;
    opacity: 0;
    transform: translateY(16px);
    animation: fadeUp 0.4s forwards;
  }

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

  .q-number {
    font-family: 'Shippori Mincho B1', monospace;
    font-size: 0.7rem;
    color: var(--accent);
    letter-spacing: 0.12em;
    text-transform: uppercase;
    margin-bottom: 14px;
  }

  .q-text {
    font-size: 1rem;
    font-weight: 500;
    line-height: 1.55;
    margin-bottom: 24px;
    color: var(--text);
  }

  .options { display: flex; flex-direction: column; gap: 10px; }

  .option-btn {
    background: var(--bg);
    border: 1px solid var(--border);
    color: var(--text);
    font-family: 'Shippori Mincho B1', monospace;
    font-size: 1.05rem;
    text-align: left;
    padding: 20px 24px;
    border-radius: var(--radius);
    cursor: pointer;
    transition: border-color 0.15s, background 0.15s;
    line-height: 1.5;
  }

  .option-btn:hover:not(:disabled):not(.selected) {
    border-color: var(--accent-dim);
    background: #1a1f2a;
  }

  .option-btn.selected {
    background: var(--selected);
    border-color: var(--selected-border);
    color: #a8c8ff;
  }

  .option-btn.correct {
    background: var(--correct-dim);
    border-color: var(--correct);
    color: var(--correct);
    font-weight: 500;
  }

  .option-btn.wrong {
    background: var(--wrong-dim);
    border-color: var(--wrong);
    color: var(--wrong);
  }

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

  .option-btn.missed {
    border-color: var(--correct);
    color: var(--correct);
    opacity: 0.5;
  }

  .q-hint {
    font-family: 'Shippori Mincho B1', monospace;
    font-size: 0.7rem;
    color: var(--muted);
    letter-spacing: 0.05em;
    text-transform: uppercase;
    margin-bottom: 18px;
  }

  .feedback {
    margin-top: 18px;
    font-family: 'Shippori Mincho B1', monospace;
    font-size: 0.8rem;
    padding: 10px 14px;
    border-radius: var(--radius);
    display: none;
  }
  .feedback.show { display: block; }
  .feedback.ok { background: var(--correct-dim); color: var(--correct); border: 1px solid var(--correct); }
  .feedback.bad { background: var(--wrong-dim); color: var(--wrong); border: 1px solid var(--wrong); }

  .action-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 24px;
    gap: 12px;
  }

  .btn-confirm {
    background: transparent;
    border: 1px solid var(--selected-border);
    color: #fff;
    font-family: 'Shippori Mincho B1', monospace;
    font-weight: 500;
    font-size: 0.85rem;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    padding: 12px 28px;
    border-radius: var(--radius);
    cursor: pointer;
    transition: all 0.2s;
    display: none;
  }
  .btn-confirm.show { display: inline-block; }
  .btn-confirm:hover { background: var(--selected); }

  .btn-next {
    background: var(--accent);
    color: #000;
    border: none;
    font-family: 'Shippori Mincho B1', monospace;
    font-weight: 500;
    font-size: 0.85rem;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    padding: 12px 28px;
    border-radius: var(--radius);
    cursor: pointer;
    display: none;
    transition: opacity 0.2s;
  }
  .btn-next:hover { opacity: 0.85; }
  .btn-next.show { display: inline-block; }

  .q-counter {
    font-family: 'Shippori Mincho B1', monospace;
    font-size: 0.75rem;
    color: var(--muted);
    flex: 1;
  }

  /* STUDY MODE */
  .study-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 28px 32px;
    margin-bottom: 20px;
  }
  .study-q {
    font-size: 0.95rem;
    font-weight: 500;
    line-height: 1.55;
    margin-bottom: 18px;
    color: var(--text);
  }
  .study-q-num {
    font-family: 'Shippori Mincho B1', monospace;
    font-size: 0.65rem;
    color: var(--accent);
    letter-spacing: 0.12em;
    text-transform: uppercase;
    margin-bottom: 10px;
  }
  .study-options { display: flex; flex-direction: column; gap: 8px; }
  .study-opt {
    font-size: 0.88rem;
    padding: 10px 14px;
    border-radius: var(--radius);
    border: 1px solid var(--border);
    background: var(--bg);
    line-height: 1.4;
  }
  .study-opt.correct-ans {
    background: var(--correct-dim);
    border-color: var(--correct);
    color: var(--correct);
    font-weight: 500;
  }

  /* RESULTS */
  #results {
    display: none;
    text-align: center;
    padding: 60px 0;
  }
  #results h2 {
    font-size: 2.5rem;
    font-weight: 500;
    color: var(--accent);
    margin-bottom: 12px;
  }
  #results p {
    color: var(--muted);
    font-family: 'Shippori Mincho B1', monospace;
    font-size: 0.9rem;
    margin-bottom: 32px;
  }
  .btn-restart {
    background: transparent;
    border: 1px solid var(--accent);
    color: var(--accent);
    font-family: 'Shippori Mincho B1', monospace;
    font-weight: 500;
    font-size: 0.85rem;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    padding: 12px 28px;
    border-radius: var(--radius);
    cursor: pointer;
    transition: background 0.2s, color 0.2s;
  }
  .btn-restart:hover { background: var(--accent); color: #000; }