:root{font-family:-apple-system,BlinkMacSystemFont,"PingFang SC","Microsoft YaHei",sans-serif;color:#17202c;background:#f6f7f9;font-size:16px;line-height:1.65;--blue:#215be0;--muted:#657184;--line:#e6e9ef}*{box-sizing:border-box}body{margin:0}button,input,select{font:inherit}button,a,input,select{-webkit-tap-highlight-color:transparent}button{cursor:pointer;border:0}button:disabled{opacity:.42;cursor:default}button:focus-visible,a:focus-visible,select:focus-visible{outline:3px solid #8bacf5;outline-offset:3px}a{color:var(--blue);text-decoration:none}header{display:flex;align-items:center;justify-content:space-between;margin-bottom:26px;gap:12px}h1{font-size:25px;letter-spacing:-.7px;margin:0;font-weight:650}h2{font-size:20px;margin:0 0 16px}h3{font-size:16px;margin:0 0 10px}p{margin:0 0 14px}.shell{max-width:720px;margin:auto;padding:28px 22px calc(104px + env(safe-area-inset-bottom))}.muted,.meta{color:var(--muted);font-size:14px}.meta{margin-bottom:16px}.card{background:white;border:1px solid var(--line);border-radius:16px;padding:22px;margin-bottom:16px}.subject-grid{display:grid;grid-template-columns:1fr 1fr;gap:12px}.subject{background:#fff;border:1px solid var(--line);border-radius:14px;padding:22px 18px;text-align:left;color:inherit;min-height:108px}.subject strong{display:block;font-size:18px;font-weight:600}.subject small{display:block;font-size:14px;color:var(--muted);margin-top:7px}.subject:hover,.row:hover{border-color:#a7bdf0}.subject.active{border-color:var(--blue)}.primary{background:var(--blue);color:white;padding:13px 22px;border-radius:11px;font-weight:550;min-height:48px}.secondary{background:#edf2fc;color:#1f50b8;padding:12px 20px;border-radius:11px;min-height:48px}.plain{padding:8px 4px;color:var(--muted);background:transparent;min-height:44px}.wide{width:100%}.row{width:100%;display:flex;align-items:center;justify-content:space-between;gap:12px;text-align:left;background:white;color:inherit;border:1px solid var(--line);border-radius:12px;padding:16px;margin-bottom:10px}.row span{min-width:0}.row small{white-space:nowrap;color:var(--muted);font-size:14px}.section{margin-top:26px}.nav{position:fixed;bottom:0;left:0;right:0;background:rgba(255,255,255,.98);border-top:1px solid var(--line);display:flex;justify-content:center;padding-bottom:env(safe-area-inset-bottom);z-index:10}.nav button{background:transparent;color:var(--muted);padding:17px 6px;flex:1;max-width:170px;font-size:15px}.nav button.active{color:var(--blue);font-weight:650}.q-stem{font-size:19px;line-height:1.85;margin:18px 0 24px;overflow-wrap:anywhere}.options{display:grid;gap:12px}.option{display:flex;align-items:flex-start;gap:14px;width:100%;text-align:left;background:#fff;border:1px solid #dce1e9;border-radius:12px;padding:16px;color:inherit;line-height:1.7}.letter{flex:0 0 28px;width:28px;height:28px;display:grid;place-items:center;border:1px solid #dce1e9;border-radius:50%;font-size:14px}.option.selected{border-color:var(--blue);background:#f0f5ff}.option.selected .letter{background:var(--blue);border-color:var(--blue);color:#fff}.option.correct{border-color:#258864;background:#eef8f3}.option.wrong{border-color:#d05858;background:#fff3f2}.option:disabled{opacity:1}.question-top{display:flex;justify-content:space-between;align-items:center;gap:12px}.question-top button{font-size:14px}.actions{display:flex;gap:12px;align-items:center;margin:22px 0}.actions>*{flex:1}.answer{border-top:1px solid var(--line);margin-top:24px;padding-top:22px}.answer p{overflow-wrap:anywhere}.correct-text{color:#187552}.wrong-text{color:#b33d3d}details{border-top:1px solid var(--line);padding:15px 0}summary{cursor:pointer;font-size:15px}.note{padding:16px;background:#f3f6fc;border-radius:10px;margin:14px 0;font-size:15px}.note p:last-child{margin:0}.stats{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;text-align:center;margin-bottom:16px}.stat strong{font-size:25px;display:block;font-weight:600}.stat span{font-size:14px;color:var(--muted)}progress{width:100%;height:6px;appearance:none;border:0;border-radius:6px;overflow:hidden;background:#e8ecf2}progress::-webkit-progress-bar{background:#e8ecf2}progress::-webkit-progress-value{background:var(--blue)}.loading,.empty{padding:40px 10px;text-align:center;color:var(--muted)}#toast{position:fixed;bottom:110px;left:50%;transform:translateX(-50%);background:#17202c;color:white;border-radius:10px;padding:10px 18px;max-width:90vw;z-index:50;display:none;font-size:14px}select{max-width:100%;border:1px solid var(--line);border-radius:9px;padding:9px 12px;background:white;color:inherit}.stack{display:grid;gap:12px}.count{font-variant-numeric:tabular-nums}.pill{color:var(--muted);font-size:14px}.paper-title{font-size:16px;line-height:1.6}.reading{white-space:pre-wrap;line-height:1.9;overflow-wrap:anywhere}.hint{font-size:14px;color:var(--muted);margin-top:12px}.review-list{display:flex;gap:6px;flex-wrap:wrap}.review-list button{min-width:42px;min-height:42px;border-radius:7px;background:#edf2fc;color:var(--blue)}@media(max-width:480px){.shell{padding:22px 18px calc(100px + env(safe-area-inset-bottom))}.card{padding:18px}.q-card{padding:0;border:0;background:transparent}.q-stem{font-size:18px}.subject{padding:19px 15px}.option{padding:14px}h1{font-size:23px}}@media(min-width:900px){.shell{padding-top:44px}.subject-grid{gap:16px}.subject{padding:25px}.nav{border-radius:16px 16px 0 0;max-width:720px;margin:auto;border:1px solid var(--line)}}