:root{--p:#2563eb;--ok:#16a34a;--bad:#dc2626;--bg:#f5f6f8;--card:#fff;--line:#e5e7eb;--muted:#6b7280}
*{box-sizing:border-box;-webkit-tap-highlight-color:transparent}
body{margin:0;background:var(--bg);color:#111;font:15px/1.55 -apple-system,"PingFang SC","Microsoft YaHei",sans-serif}
.hidden{display:none!important}
.muted{color:var(--muted);font-size:13px}
.err{color:var(--bad);font-size:13px;min-height:18px}
button{font:inherit;cursor:pointer;border:none;border-radius:10px;padding:10px 16px;background:#e8eaf0}
button.primary{background:var(--p);color:#fff}
button.ghost{background:#fff;border:1px solid var(--line)}
button:disabled{opacity:.4}
a.ghost{display:inline-block;padding:8px 14px;border:1px solid var(--line);border-radius:10px;background:#fff;color:var(--p);text-decoration:none;font-size:14px}
.card{background:var(--card);border-radius:14px;padding:16px;margin:12px}
.card h3{margin:0 0 10px;font-size:16px}
.field{display:flex;align-items:center;gap:10px;margin-bottom:10px}
.field label{width:44px;color:var(--muted);font-size:14px;flex:none}
.field select{flex:1;padding:9px;border:1px solid var(--line);border-radius:9px;background:#fff;font:inherit}

/* gate */
.gate{position:fixed;inset:0;background:var(--bg);display:flex;align-items:center;justify-content:center;z-index:50}
.gate-card{background:#fff;border-radius:16px;padding:28px 24px;width:min(88vw,340px);text-align:center;box-shadow:0 8px 30px rgba(0,0,0,.08)}
.gate-card h1{margin:0;font-size:22px}
.gate-card p{color:var(--muted);margin:6px 0 18px}
.gate-card input{width:100%;padding:11px;border:1px solid var(--line);border-radius:10px;font:inherit;margin-bottom:10px;text-align:center}
.gate-card button{width:100%;background:var(--p);color:#fff}

/* main layout */
#main{padding-bottom:76px}
.view{padding-top:10px}
#nav{position:fixed;bottom:0;left:0;right:0;display:flex;background:#fff;border-top:1px solid var(--line);padding:6px 0 calc(6px + env(safe-area-inset-bottom));z-index:40}
#nav button{flex:1;background:none;color:var(--muted);font-size:12px;padding:4px 0;border-radius:0}
#nav button span{display:block;font-size:20px;line-height:1.2}
#nav button.on{color:var(--p);font-weight:600}

/* filters */
.filters{background:#fff;padding:10px 12px;border-radius:14px;margin:0 12px 4px}
.seg{display:flex;gap:6px;margin-bottom:8px}
.seg button{flex:1;padding:7px 0;background:#f1f2f6;font-size:14px;border-radius:8px}
.seg button.on{background:var(--p);color:#fff}
.filters select{width:100%;padding:8px;border:1px solid var(--line);border-radius:9px;background:#fff;font:inherit}
.row2{display:flex;justify-content:space-between;align-items:center;margin-top:8px}
.chk{font-size:13px;color:var(--muted);display:flex;align-items:center;gap:5px}

/* question card */
.q{background:#fff;border-radius:14px;margin:10px 12px;padding:14px}
.q .meta{display:flex;gap:6px;align-items:center;margin-bottom:8px;flex-wrap:wrap}
.tag{font-size:11px;padding:2px 8px;border-radius:99px;background:#eef2ff;color:var(--p)}
.tag.warn{background:#fef3c7;color:#92400e}
.q .stem{font-weight:600;margin-bottom:10px}
.opt{display:block;width:100%;text-align:left;background:#f7f8fa;border:1px solid var(--line);border-radius:10px;padding:10px 12px;margin:7px 0;font-size:14px}
.opt.sel{border-color:var(--p);background:#eef2ff}
.opt.right{border-color:var(--ok);background:#f0fdf4}
.opt.wrong{border-color:var(--bad);background:#fef2f2}
.opt:disabled{cursor:default}
.fb{margin-top:10px;padding-top:10px;border-top:1px dashed var(--line);font-size:13px}
.fb .v{font-weight:700}
.fb .v.ok{color:var(--ok)}.fb .v.bad{color:var(--bad)}
.fb .exp{color:#374151;margin-top:6px;white-space:pre-wrap}
.multi-confirm{margin-top:6px;background:var(--p);color:#fff}

/* mini */
.mini-head{display:flex;justify-content:space-between;align-items:center;padding:0 16px;font-size:14px;font-weight:600}
.head-right{display:flex;align-items:center;gap:10px}
.timer{font-variant-numeric:tabular-nums;font-weight:700;color:var(--p);font-size:15px}
.submit-btn{background:none;border:1px solid var(--p);color:var(--p);padding:5px 12px;font-size:13px;border-radius:99px}
button.wide{width:100%;margin-top:10px}
.filters .tip{margin:8px 0 0;text-align:center}
.bar{height:5px;background:#e5e7eb;border-radius:99px;margin:8px 16px}
.bar i{display:block;height:100%;background:var(--p);border-radius:99px;transition:width .2s;width:0}
.mini-nav{display:flex;gap:10px;padding:4px 12px 12px}
.mini-nav button{flex:1}
.lucky{display:flex;align-items:center;gap:6px;font-size:13px;color:var(--muted);margin-top:8px}
#mini-result .score,#drill-result .score{text-align:center;font-size:30px;font-weight:800;padding:18px 0 4px}
#mini-result .sub,#drill-result .sub{text-align:center;color:var(--muted);margin-bottom:10px}
.redo-row{margin-top:8px}
button.redo{padding:6px 12px;font-size:12px}

/* 交卷确认弹层 */
.submit-mask{position:fixed;inset:0;background:rgba(0,0,0,.4);display:flex;align-items:center;justify-content:center;z-index:80}
.submit-box{background:#fff;border-radius:16px;padding:22px 24px;width:min(80vw,300px);text-align:center}
.submit-box p{margin:0 0 16px;font-size:15px}
.submit-box b{color:var(--bad)}
.submit-box .row{display:flex;gap:10px}
.submit-box .row button{flex:1}

/* wrong */
.wrong-head{margin:0 12px}
.due-pill{font-size:13px;color:var(--muted);padding:4px 2px}
.due-pill b{color:var(--bad)}

/* toast */
#toast{position:fixed;left:50%;bottom:88px;transform:translateX(-50%) translateY(8px);background:rgba(17,24,39,.88);color:#fff;padding:9px 18px;border-radius:99px;font-size:13px;opacity:0;pointer-events:none;transition:opacity .25s,transform .25s;z-index:99;max-width:80vw;text-align:center}
#toast.show{opacity:1;transform:translateX(-50%) translateY(0)}
.export-row{display:flex;gap:8px;margin:8px 0}
.wrong-item{display:flex;justify-content:space-between;align-items:center;background:#fff;border-radius:12px;margin:8px 12px;padding:12px 14px;gap:10px}
.wrong-item .t{flex:1;font-size:14px}
.wrong-item .s{font-size:12px;color:var(--muted);margin-top:2px}
.badge{flex:none;font-size:11px;padding:3px 9px;border-radius:99px;background:#fee2e2;color:var(--bad);font-weight:600}
.badge.ok{background:#dcfce7;color:var(--ok)}

/* more */
.foot{text-align:center;color:var(--muted);font-size:13px;padding:10px}
#sync-status .dot{display:inline-block;width:8px;height:8px;border-radius:99px;margin-right:5px;background:var(--muted)}
#sync-status .dot.ok{background:var(--ok)}
#sync-status .dot.pend{background:#f59e0b}