* { box-sizing: border-box; margin: 0; padding: 0; }
  :root {
    --bg: #0b1220;
    --bg-2: #111a2e;
    --panel: #16223a;
    --panel-2: #1c2a47;
    --text: #e7ecf4;
    --muted: #8b97ad;
    --accent: #f5c542;
    --accent-2: #f59e42;
    --success: #34d399;
    --danger: #1e1e1e;
    --border: rgba(255,255,255,0.08);
  }
  html, body {
    height: 100%;
    background: radial-gradient(1200px 800px at 20% -10%, #1a2a52 0%, transparent 60%),
                radial-gradient(1000px 700px at 110% 110%, #2a1a4a 0%, transparent 60%),
                var(--bg);
    color: var(--text);
    font-family: 'Inter', 'Noto Sans JP', system-ui, sans-serif;
    overflow-x: hidden;
  }
  .app {
    max-width: 980px;
    margin: 0 auto;
    padding: 28px 22px 160px;
    min-height: 100vh;
  }
  header {
    display: flex;
    align-items: center;
    gap: 16px;
    margin-bottom: 24px;
  }
  .logo {
    width: 56px; height: 56px;
    border-radius: 14px;
    background: linear-gradient(135deg, var(--accent), var(--accent-2));
    display: flex; align-items: center; justify-content: center;
    font-size: 28px; font-weight: 900; color: #0b1220;
    box-shadow: 0 10px 30px rgba(0,0,0,0.4);
  }
  .title { font-size: 22px; font-weight: 800; letter-spacing: 0.3px; }
  .title .accent { color: var(--accent); }
  .subtitle { color: var(--muted); font-size: 13px; margin-top: 2px; }
  .stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
    gap: 12px;
    margin: 22px 0;
  }
  .stat {
    background: linear-gradient(180deg, var(--panel) 0%, var(--panel-2) 100%);
    border: 1px solid var(--border);
    border-radius: 14px;
    padding: 14px 16px;
    display: flex;
    flex-direction: column;
    gap: 4px;
  }
  .stat .label { color: var(--muted); font-size: 11px; text-transform: uppercase; letter-spacing: 1px; }
  .stat .value { font-size: 22px; font-weight: 800; }
  .stat .value.accent { color: var(--accent); }
  .stat .value.success { color: var(--success); }
  .stat .value.danger { color: var(--danger); }

  .progress-bar {
    height: 8px;
    background: var(--panel);
    border-radius: 999px;
    overflow: hidden;
    margin: 14px 0 22px;
    border: 1px solid var(--border);
  }
  .progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--accent), var(--accent-2));
    border-radius: 999px;
    transition: width 0.6s cubic-bezier(.2,.8,.2,1);
  }

  .mode-toggle {
    display: flex;
    gap: 8px;
    margin-bottom: 18px;
    flex-wrap: wrap;
  }
  .mode-btn {
    background: var(--panel);
    border: 1px solid var(--border);
    color: var(--text);
    padding: 10px 16px;
    border-radius: 10px;
    font-size: 13px;
    cursor: pointer;
    transition: all 0.2s;
    font-family: inherit;
  }
  .mode-btn:hover { background: var(--panel-2); }
  .mode-btn.active {
    background: linear-gradient(135deg, var(--accent), var(--accent-2));
    color: #0b1220;
    font-weight: 700;
    border-color: transparent;
  }

  .card {
    background: linear-gradient(180deg, var(--panel) 0%, var(--panel-2) 100%);
    border: 1px solid var(--border);
    border-radius: 20px;
    padding: 36px 28px;
    text-align: center;
    position: relative;
    overflow: hidden;
    box-shadow: 0 20px 60px rgba(0,0,0,0.3);
  }
  .card::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--accent), var(--accent-2), var(--accent));
  }
  .q-type {
    font-size: 11px;
    text-transform: uppercase;
    letter-spacing: 2px;
    color: var(--muted);
    margin-bottom: 10px;
  }
  .q-prompt {
    font-family: 'Noto Sans JP', sans-serif;
    font-size: 64px;
    font-weight: 700;
    margin: 10px 0 6px;
    line-height: 1.2;
    word-break: break-word;
  }
  .q-hint {
    color: var(--muted);
    font-size: 13px;
    margin-bottom: 28px;
  }
  .options {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
  }
  .option {
    background: var(--bg-2);
    border: 2px solid var(--border);
    border-radius: 14px;
    padding: 20px 16px;
    cursor: pointer;
    font-family: 'Noto Sans JP', 'Inter', sans-serif;
    font-size: 18px;
    color: var(--text);
    transition: all 0.2s;
    text-align: center;
    min-height: 72px;
    display: flex;
    align-items: center;
    justify-content: center;
    word-break: break-word;
  }
  .option:hover:not(:disabled) {
    border-color: var(--accent);
    transform: translateY(-2px);
    background: var(--panel);
  }
  .option:disabled { cursor: default; }
  .option.correct {
    border-color: var(--success);
    background: rgba(52, 211, 153, 0.15);
    color: var(--success);
  }
  .option.wrong {
    border-color: var(--danger);
    background: rgba(248, 113, 113, 0.12);
    color: var(--danger);
  }
  .option.reveal {
    border-color: var(--success);
    background: rgba(52, 211, 153, 0.1);
  }

  .answer-panel {
    position: fixed;
    left: 0; right: 0; bottom: 0;
    background: linear-gradient(180deg, var(--panel-2) 0%, var(--panel) 100%);
    border-top: 1px solid var(--border);
    padding: 22px;
    transform: translateY(100%);
    transition: transform 0.35s cubic-bezier(.2,.8,.2,1);
    z-index: 50;
    box-shadow: 0 -10px 40px rgba(0,0,0,0.4);
  }
  .answer-panel.visible { transform: translateY(0); }
  .answer-inner { max-width: 980px; margin: 0 auto; }
  .result-header {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 14px;
  }
  .result-icon {
    width: 44px; height: 44px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 22px;
    font-weight: 800;
  }
  .result-icon.success { background: rgba(52, 211, 153, 0.2); color: var(--success); }
  .result-icon.fail { background: rgba(248, 113, 113, 0.2); color: var(--danger); }
  .result-title { font-size: 18px; font-weight: 700; }
  .result-sub { font-size: 13px; color: var(--muted); }
  .answer-details {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 10px;
    margin-bottom: 18px;
  }
  .detail {
    background: var(--bg-2);
    border: 1px solid var(--border);
    border-radius: 10px;
    padding: 12px;
  }
  .detail .label {
    font-size: 10px;
    text-transform: uppercase;
    letter-spacing: 1.5px;
    color: var(--muted);
    margin-bottom: 4px;
  }
  .detail .value {
    font-family: 'Noto Sans JP', sans-serif;
    font-size: 20px;
    font-weight: 700;
  }
  .detail .value.en { font-family: 'Inter', sans-serif; font-size: 16px; }
  .continue-btn {
    width: 100%;
    padding: 16px;
    background: linear-gradient(135deg, var(--accent), var(--accent-2));
    color: #0b1220;
    border: none;
    border-radius: 12px;
    font-size: 16px;
    font-weight: 800;
    cursor: pointer;
    font-family: inherit;
    transition: transform 0.15s;
  }
  .continue-btn:hover { transform: translateY(-2px); }
  .continue-btn:active { transform: translateY(0); }

  .footer-note {
    text-align: center;
    color: var(--muted);
    font-size: 12px;
    margin-top: 20px;
    line-height: 1.6;
  }
  .footer-note strong { color: var(--accent); }

  @media (max-width: 600px) {
    .q-prompt { font-size: 48px; }
    .options { grid-template-columns: 1fr; }
    .app { padding: 20px 14px 180px; }
  }