:root{--bg: #ffffff;--fg: #000000;--accent: #1d1d1f;--divider: #e5e5ea;--muted: #86868b;--card-bg: #ffffff;--success: #2e7d32;--danger: #c62828;--radius: 20px}[data-theme=dark]{--bg: #000000;--fg: #ffffff;--accent: #f5f5f7;--divider: #38383a;--muted: #98989d;--card-bg: #0a0a0a}*{box-sizing:border-box;margin:0;padding:0}html,body{height:100%}body{font-family:PingFang SC,Hiragino Sans GB,Lxgw WenKai,system-ui,-apple-system,sans-serif;background:var(--bg);color:var(--fg);transition:background .3s ease,color .3s ease;-webkit-font-smoothing:antialiased}#root{max-width:720px;margin:0 auto;padding:20px;position:relative}a{color:inherit;text-decoration:none}.muted{color:var(--muted)}.theme-btn{position:fixed;top:18px;right:18px;z-index:10;width:40px;height:40px;border-radius:50%;border:1px solid var(--divider);background:var(--bg);color:var(--fg);cursor:pointer;display:flex;align-items:center;justify-content:center;transition:border-color .2s ease}.theme-btn:hover{border-color:var(--accent)}.topnav{display:flex;align-items:center;justify-content:space-between;font-size:14px;color:var(--muted)}.btn-link{display:inline-flex;align-items:center;gap:4px;border:none;background:none;color:inherit;cursor:pointer;font-size:14px;padding:4px 0}.btn-link:hover{color:var(--fg)}.progress-track{height:3px;background:var(--divider);margin:14px 0 22px;border-radius:2px;overflow:hidden}.progress-fill{height:100%;background:var(--accent);transition:width .3s ease}.home{text-align:center;padding-top:8vh}.home .logo{margin-bottom:18px}.home h1{font-size:44px;font-weight:600;letter-spacing:6px}.divider{width:56px;height:1px;background:var(--divider);margin:26px auto}.home .sub{color:var(--muted);font-size:15px;line-height:2}.mode-grid{display:grid;gap:14px;margin:34px 0 8px;text-align:left}.mode-card{display:block;border:1px solid var(--divider);border-radius:var(--radius);padding:20px;background:var(--card-bg);transition:border-color .2s ease,transform .15s ease}.mode-card:hover{border-color:var(--accent);transform:translateY(-2px)}.mode-icon{color:var(--accent);margin-bottom:10px}.mode-name{font-size:17px;font-weight:600;margin-bottom:4px}.mode-desc{font-size:13px;color:var(--muted)}.stat-strip{display:flex;justify-content:center;gap:20px;margin:22px 0 4px;font-size:13px;color:var(--muted)}.footer-links{display:flex;justify-content:center;gap:28px;margin-top:26px;color:var(--muted)}.btn{display:inline-flex;align-items:center;justify-content:center;padding:12px 36px;border-radius:var(--radius);background:var(--accent);color:var(--bg);border:1px solid transparent;cursor:pointer;font-size:16px;transition:opacity .2s ease,transform .1s ease}.btn:hover{opacity:.85}.btn:active{transform:scale(.98)}.btn.ghost{background:transparent;color:var(--fg);border-color:var(--divider)}.btn.ghost:hover{border-color:var(--accent);opacity:1}.danger-text{color:var(--danger)}.page h1{font-size:28px;font-weight:600;margin:8px 0 14px}.section-title{font-size:15px;font-weight:600;margin:28px 0 12px}.quiz-card h2{font-size:17px;font-weight:500;text-align:center;line-height:1.8;margin-bottom:22px}.options{display:grid;gap:14px}.option{border:1px solid var(--divider);border-radius:var(--radius);padding:18px 16px;cursor:pointer;background:var(--card-bg);transition:border-color .2s ease,background .2s ease}.option:hover{border-color:var(--accent)}.option .tag{font-size:13px;color:var(--muted);margin-bottom:12px}.option p{font-size:15px;line-height:1.9;white-space:pre-wrap}.option img{width:100%;height:auto;display:block;border-radius:12px}.option.correct{border-color:var(--success);background:#2e7d3214}.option.wrong{border-color:var(--danger);background:#c628280f;opacity:.55}.option.locked{cursor:default}.option.locked:hover{border-color:var(--divider)}.option.locked.correct:hover{border-color:var(--success)}.timer-track{height:4px;background:var(--divider);margin:14px 0 6px;border-radius:2px;overflow:hidden}.timer-fill{height:100%;background:var(--accent);transition:width 1s linear}.timer-fill.danger{background:var(--danger)}.timer-label{text-align:center;font-size:13px;color:var(--muted);margin-bottom:20px}.feedback{text-align:center;margin-top:22px;font-size:15px}.feedback .ok{color:var(--success)}.feedback .no{color:var(--danger)}.actions{display:flex;justify-content:center;gap:12px;margin-top:22px;flex-wrap:wrap}.result{text-align:center;padding-top:8vh}.result h1{font-size:22px;font-weight:600;margin-top:12px}.result .score{font-size:64px;font-weight:600;margin:12px 0}.result .msg{color:var(--muted);font-size:15px;line-height:1.9}.review{margin-top:36px;text-align:left}.review h3{font-size:15px;font-weight:600;margin-bottom:12px;text-align:center}.review-item{display:flex;align-items:center;gap:10px;padding:10px 14px;border:1px solid var(--divider);border-radius:12px;margin-bottom:8px;font-size:14px}.review-item.ok .review-icon{color:var(--success)}.review-item.no .review-icon{color:var(--danger)}.review-q{font-weight:600;flex-shrink:0}.review-a{color:var(--muted)}.stat-cards{display:grid;grid-template-columns:repeat(2,1fr);gap:12px;margin-top:18px}.stat-card{border:1px solid var(--divider);border-radius:var(--radius);padding:20px;text-align:center}.stat-num{font-size:32px;font-weight:600}.stat-label{font-size:13px;color:var(--muted);margin-top:6px}.empty{color:var(--muted);font-size:14px;text-align:center;padding:20px 0}.history-list{margin-bottom:10px}.history-item{display:flex;align-items:center;gap:12px;padding:10px 14px;border:1px solid var(--divider);border-radius:12px;margin-bottom:8px;font-size:14px}.history-mode{font-weight:600}.history-score{color:var(--accent)}.history-date{margin-left:auto;color:var(--muted);font-size:12px}.about p,.about-list{font-size:15px;line-height:2;color:var(--fg)}.about-list{padding-left:20px}@media (min-width: 769px){#root{max-width:900px}.options,.mode-grid{grid-template-columns:1fr 1fr}.stat-cards{grid-template-columns:repeat(4,1fr)}}