:root{
  --bg:#f6f7f9; --surface:#ffffff; --surface-2:#f2f3f5; --border:#e8eaee;
  --text:#1f2329; --text-dim:#5b616b; --text-faint:#959ba5;
  --brand:#2f6bff; --brand-soft:#eef3ff; --brand-dark:#1f55e0;
  --ok:#119e6a; --ok-soft:#e8f7f0; --bad:#e5484d; --bad-soft:#fdeeee;
  --warn:#d9822b; --warn-soft:#fdf4ea;
  --radius:14px; --fs:16px;
}
@media (prefers-color-scheme:dark){
  :root:not([data-theme]){
    --bg:#111317; --surface:#181b20; --surface-2:#1f232a; --border:#2a2f37;
    --text:#e6e8eb; --text-dim:#a4a9b1; --text-faint:#737a84;
    --brand:#6b9bff; --brand-soft:#1b2436; --brand-dark:#89afff;
    --ok:#3fcf94; --ok-soft:#14261e; --bad:#ff7b7f; --bad-soft:#2c1719;
    --warn:#f0a95a; --warn-soft:#2a2016;
  }
}
/* 护眼：豆沙绿底、低对比暖色文字 */
:root[data-theme="eye"]{
  --bg:#cfe6cf; --surface:#e4f1df; --surface-2:#d7ead3; --border:#b8d4b8;
  --text:#27362b; --text-dim:#4a5d4e; --text-faint:#768a79;
  --brand:#2f6f9f; --brand-soft:#d3e6e3; --brand-dark:#245b85;
  --ok:#1d8454; --ok-soft:#d2ebd3; --bad:#c2453f; --bad-soft:#efdcd2;
  --warn:#a86a1c; --warn-soft:#ece4c8;
}
:root[data-theme="dark"]{
  --bg:#111317; --surface:#181b20; --surface-2:#1f232a; --border:#2a2f37;
  --text:#e6e8eb; --text-dim:#a4a9b1; --text-faint:#737a84;
  --brand:#6b9bff; --brand-soft:#1b2436; --brand-dark:#89afff;
  --ok:#3fcf94; --ok-soft:#14261e; --bad:#ff7b7f; --bad-soft:#2c1719;
  --warn:#f0a95a; --warn-soft:#2a2016;
}
*{box-sizing:border-box}
html{-webkit-tap-highlight-color:transparent;font-size:var(--fs)}
body{margin:0;background:var(--bg);color:var(--text);font-size:1rem;line-height:1.7;
  font-family:"PingFang SC","Microsoft YaHei","Hiragino Sans GB","Source Han Sans SC",system-ui,-apple-system,"Segoe UI",sans-serif;
  -webkit-text-size-adjust:100%;-webkit-font-smoothing:antialiased}
button{font:inherit;color:inherit;cursor:pointer;border:none;background:none;padding:0}
a{color:var(--brand)}
.wrap{max-width:760px;margin:0 auto;padding:4px 16px 110px}

/* top bar */
.topbar{position:sticky;top:0;z-index:40;background:color-mix(in srgb,var(--bg) 88%,transparent);
  backdrop-filter:saturate(1.4) blur(10px);-webkit-backdrop-filter:saturate(1.4) blur(10px)}
.topbar-in{max-width:760px;margin:0 auto;padding:8px 10px;display:flex;align-items:center;gap:4px;min-height:52px}
.tb-title{font-weight:600;font-size:.98rem;flex:1;min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;padding:0 6px}
.tb-sub{font-size:.78rem;color:var(--text-faint);font-weight:400;margin-left:6px}
.iconbtn{width:38px;height:38px;border-radius:10px;display:grid;place-items:center;color:var(--text-dim);flex:none}
.iconbtn:hover{background:var(--surface-2);color:var(--text)}
.iconbtn.on{color:var(--warn)}
.foot{text-align:center;font-size:.72rem;color:var(--text-faint);margin:36px 0 4px;letter-spacing:.12em}
.iconbtn svg{width:20px;height:20px;fill:none;stroke:currentColor;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round}
.iconbtn.on svg{fill:currentColor}

/* generic blocks */
.card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius)}
.page-h{margin:14px 2px 18px}
.page-h h1{margin:0;font-size:1.45rem;font-weight:650;letter-spacing:-.01em;line-height:1.35}
.page-h p{margin:4px 0 0;color:var(--text-faint);font-size:.86rem}
.sec-h{font-size:.78rem;color:var(--text-faint);font-weight:500;margin:22px 4px 8px}

/* continue banner */
.resume{display:flex;align-items:center;gap:12px;width:100%;text-align:left;padding:14px 16px;margin-bottom:12px;
  background:var(--brand-soft);border-radius:var(--radius);color:var(--brand)}
.resume b{display:block;font-weight:600;font-size:.95rem}
.resume span{font-size:.8rem;opacity:.85}
.resume svg{width:18px;height:18px;margin-left:auto;flex:none;fill:none;stroke:currentColor;stroke-width:2}

/* subject cards */
.subj{display:block;width:100%;text-align:left;padding:16px 18px;margin-bottom:10px;transition:border-color .15s}
.subj:hover{border-color:color-mix(in srgb,var(--brand) 40%,var(--border))}
.subj-top{display:flex;align-items:baseline;gap:10px}
.subj-name{font-size:1.02rem;font-weight:600}
.subj-count{margin-left:auto;font-size:.8rem;color:var(--text-faint);font-variant-numeric:tabular-nums}
.bar{height:4px;border-radius:99px;background:var(--surface-2);overflow:hidden;margin-top:12px;display:flex}
.bar i{display:block;height:100%}
.bar .b-ok{background:var(--ok)} .bar .b-bad{background:var(--bad)}

/* action buttons on subject page */
.acts{display:grid;grid-template-columns:1fr 1fr;gap:10px}
.act{padding:16px;text-align:left;border-radius:var(--radius);background:var(--surface);border:1px solid var(--border);transition:border-color .15s}
.act:hover{border-color:color-mix(in srgb,var(--brand) 40%,var(--border))}
.act b{display:block;font-weight:600;font-size:.98rem}
.act span{font-size:.78rem;color:var(--text-faint)}
.act.primary{background:var(--brand);border-color:var(--brand);color:#fff}
.act.primary span{color:rgba(255,255,255,.8)}
.act.wide{grid-column:1/-1}

/* list rows */
.list{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);overflow:hidden}
.row{display:flex;align-items:center;gap:12px;width:100%;text-align:left;padding:13px 16px;border-top:1px solid var(--border);min-height:50px}
.row:first-child{border-top:none}
button.row:hover{background:var(--surface-2)}
.row-name{flex:1;min-width:0;font-size:.93rem}
.row-num{font-size:.82rem;color:var(--text-faint);font-variant-numeric:tabular-nums;flex:none}
.row-mini{font-size:.76rem;color:var(--text-faint);margin-top:1px}
.chev{width:15px;height:15px;flex:none;stroke:var(--text-faint);fill:none;stroke-width:2;stroke-linecap:round;stroke-linejoin:round}

/* quiz */
.qhead{display:flex;align-items:center;gap:8px;flex-wrap:wrap;font-size:.8rem;color:var(--text-faint);margin:8px 2px 10px}
.qhead .dot{width:3px;height:3px;border-radius:9px;background:var(--text-faint);opacity:.6}
.qhead .hot{color:var(--warn)}
.qcard{padding:20px 20px 18px}
.bg-box{background:var(--surface-2);border-radius:10px;padding:12px 14px;margin-bottom:4px;font-size:.88rem;color:var(--text-dim);white-space:pre-wrap;position:relative}
.bg-box.collapsed{max-height:5.4em;overflow:hidden}
.bg-box.collapsed::after{content:"";position:absolute;left:0;right:0;bottom:0;height:2.6em;background:linear-gradient(transparent,var(--surface-2))}
.bg-toggle{display:block;margin:6px 0 14px;font-size:.8rem;color:var(--brand)}
.stem{font-size:1.04rem;font-weight:500;white-space:pre-wrap;line-height:1.8}
.figs{margin:16px 0 4px;display:flex;flex-direction:column;align-items:center;gap:12px}
.fig{cursor:zoom-in;max-width:100%;position:relative;border-radius:8px;background:#fff;padding:6px}
.fig img{display:block;max-width:100%;height:auto}
.fig-tag{position:absolute;top:4px;left:4px;background:rgba(0,0,0,.5);color:#fff;font-size:.66rem;padding:0 6px;border-radius:99px}

.opts{margin-top:18px;display:flex;flex-direction:column;gap:10px}
.opt{display:flex;gap:12px;align-items:flex-start;padding:12px 14px;border:1px solid var(--border);
  border-radius:12px;background:var(--surface);text-align:left;width:100%;transition:border-color .12s,background .12s}
.opt:hover:not(.locked){border-color:color-mix(in srgb,var(--brand) 45%,var(--border))}
.opt.sel{border-color:var(--brand);background:var(--brand-soft)}
.opt.right{border-color:var(--ok);background:var(--ok-soft)}
.opt.wrong{border-color:var(--bad);background:var(--bad-soft)}
.opt.locked{cursor:default}
.okey{width:26px;height:26px;flex:none;border-radius:99px;border:1px solid var(--border);
  display:grid;place-items:center;font-size:.8rem;font-weight:600;color:var(--text-dim);margin-top:1px;background:var(--surface)}
.opt.multi .okey{border-radius:7px}
.opt.sel .okey{background:var(--brand);border-color:var(--brand);color:#fff}
.opt.right .okey{background:var(--ok);border-color:var(--ok);color:#fff}
.opt.wrong .okey{background:var(--bad);border-color:var(--bad);color:#fff}
.otext{flex:1;min-width:0;font-size:.96rem;white-space:pre-wrap;word-break:break-word;padding-top:1px}
.oimg{margin-top:6px;cursor:zoom-in;display:inline-block;background:#fff;border-radius:6px;padding:4px;max-width:100%}
.oimg img{display:block;max-width:100%;height:auto}

.verdict{margin-top:16px;font-size:.93rem;display:flex;gap:8px;align-items:center;font-weight:500}
.verdict.ok{color:var(--ok)} .verdict.bad{color:var(--bad)}
.verdict.warn{color:var(--warn);background:var(--warn-soft);border-radius:10px;padding:10px 13px;align-items:flex-start;line-height:1.6}
.redo{margin-top:10px;color:var(--brand);font-size:.85rem;padding:2px 0}
.verdict svg{width:18px;height:18px;flex:none;fill:none;stroke:currentColor;stroke-width:2.2;stroke-linecap:round;stroke-linejoin:round}
.expl{margin-top:14px;background:var(--surface-2);border-radius:10px;padding:13px 15px}
.expl h4{margin:0 0 6px;font-size:.78rem;color:var(--text-faint);font-weight:500;display:flex;align-items:center}
.expl h4 button{margin-left:auto;color:var(--brand);font-size:.78rem}
.expl div{white-space:pre-wrap;font-size:.92rem;color:var(--text-dim);line-height:1.85;word-break:break-word}
.expl b{font-weight:600;color:var(--text)}
.expl sub,.expl sup{font-size:.72em;line-height:0}

/* bottom bar */
.botbar{position:fixed;left:0;right:0;bottom:0;z-index:30;background:color-mix(in srgb,var(--surface) 92%,transparent);
  backdrop-filter:blur(10px);-webkit-backdrop-filter:blur(10px);
  border-top:1px solid var(--border);padding:10px 0 max(10px,env(safe-area-inset-bottom))}
.botbar-in{max-width:760px;margin:0 auto;padding:0 16px;display:flex;gap:10px;align-items:center}
.btn{padding:11px 18px;border-radius:12px;font-size:.93rem;font-weight:500;background:var(--surface-2);transition:background .12s;white-space:nowrap;text-align:center}
.btn:hover{background:color-mix(in srgb,var(--surface-2) 70%,var(--border))}
.btn.primary{background:var(--brand);color:#fff}
.btn.primary:hover{background:var(--brand-dark)}
.btn:disabled{opacity:.4;cursor:not-allowed}
.btn.grow{flex:1}
.btn.ghost{background:none;color:var(--text-dim);padding:11px 12px}
.hint{flex:1;text-align:center;font-size:.86rem;color:var(--text-faint)}

/* sheet */
.mask{position:fixed;inset:0;background:rgba(10,12,16,.4);z-index:50;opacity:0;pointer-events:none;transition:.2s}
.mask.on{opacity:1;pointer-events:auto}
.sheet{position:fixed;left:0;right:0;bottom:0;z-index:51;background:var(--surface);border-radius:18px 18px 0 0;
  max-height:82vh;display:flex;flex-direction:column;transform:translateY(100%);transition:.24s cubic-bezier(.3,.8,.4,1)}
.sheet.on{transform:translateY(0)}
.sheet-in{max-width:760px;margin:0 auto;width:100%;display:flex;flex-direction:column;min-height:0}
.sheet-h{padding:12px 12px 10px 20px;display:flex;align-items:center;gap:10px;flex:none}
.sheet-h b{font-size:.98rem;font-weight:600}
.sheet-b{overflow-y:auto;padding:4px 20px 28px}
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(42px,1fr));gap:8px}
.gcell{aspect-ratio:1;border-radius:10px;background:var(--surface-2);
  font-size:.8rem;font-variant-numeric:tabular-nums;display:grid;place-items:center;position:relative;color:var(--text-dim)}
.gcell.ok{background:var(--ok-soft);color:var(--ok)}
.gcell.bad{background:var(--bad-soft);color:var(--bad)}
.gcell.picked{box-shadow:inset 0 0 0 1px var(--brand)}
.gcell.cur{box-shadow:inset 0 0 0 2px var(--brand);color:var(--brand);font-weight:600}
.gcell.fav::after{content:"";position:absolute;top:4px;right:4px;width:5px;height:5px;border-radius:99px;background:var(--warn)}
.legend{display:flex;gap:14px;font-size:.75rem;color:var(--text-faint);margin-bottom:12px;flex-wrap:wrap}
.legend i{display:inline-block;width:9px;height:9px;border-radius:3px;margin-right:4px;vertical-align:-1px}

/* lightbox */
.lb{position:fixed;inset:0;z-index:70;background:rgba(8,10,14,.92);display:none;place-items:center;touch-action:none}
.lb.on{display:grid}
.lb img{max-width:94vw;max-height:84vh;transform-origin:center;background:#fff;border-radius:8px;padding:8px}
.lb-bar{position:absolute;top:0;left:0;right:0;padding:10px 12px;display:flex;gap:6px;align-items:center;color:#fff}
.lb-bar .iconbtn{color:#fff}
.lb-bar .iconbtn:hover{background:rgba(255,255,255,.15);color:#fff}
.lb-tip{position:absolute;bottom:14px;left:0;right:0;text-align:center;color:rgba(255,255,255,.5);font-size:.76rem}

/* forms */
.seg{display:flex;background:var(--surface-2);border-radius:11px;padding:3px;gap:3px}
.seg button{flex:1;padding:7px 8px;border-radius:8px;font-size:.84rem;color:var(--text-dim)}
.seg button.on{background:var(--surface);color:var(--text);font-weight:600;box-shadow:0 1px 2px rgba(0,0,0,.08)}
.field{margin-bottom:18px}
.field:last-child{margin-bottom:0}
.field label{display:block;font-size:.8rem;color:var(--text-faint);margin-bottom:7px}
.empty{text-align:center;padding:56px 20px;color:var(--text-faint);font-size:.9rem}
.empty svg{width:40px;height:40px;stroke:currentColor;fill:none;stroke-width:1.4;opacity:.5;margin-bottom:8px}
input[type=text],input[type=number],input[type=search],select,textarea{width:100%;padding:11px 13px;border-radius:11px;border:1px solid var(--border);
  background:var(--surface);color:var(--text);font:inherit;font-size:.93rem}
input:focus,select:focus,textarea:focus{outline:2px solid var(--brand);outline-offset:-1px;border-color:transparent}
.toast{position:fixed;left:50%;bottom:90px;transform:translateX(-50%) translateY(12px);z-index:80;
  background:var(--text);color:var(--bg);padding:9px 17px;border-radius:99px;font-size:.85rem;
  opacity:0;pointer-events:none;transition:.22s;max-width:86vw;text-align:center}
.toast.on{opacity:1;transform:translateX(-50%) translateY(0)}
.hl{background:var(--warn-soft);color:var(--warn);border-radius:3px;padding:0 2px}
.timer{font-variant-numeric:tabular-nums;font-size:.86rem;color:var(--text-dim);padding:0 8px}
.timer.warn{color:var(--bad)}
.kbd{display:inline-block;min-width:18px;padding:0 4px;border:1px solid var(--border);border-bottom-width:2px;
  border-radius:4px;font-size:.72rem;color:var(--text-faint);text-align:center;font-family:ui-monospace,monospace}
.statline{display:grid;grid-template-columns:repeat(4,1fr);text-align:center;padding:14px 6px}
.statline b{display:block;font-size:1.2rem;font-weight:600;font-variant-numeric:tabular-nums}
.statline span{font-size:.74rem;color:var(--text-faint)}
.jump{display:flex;gap:8px;padding:12px}
.jump .btn{flex:none}
@media(max-width:600px){
  .qcard{padding:16px}
  .wrap{padding:2px 12px 104px}
  .botbar-in{padding-left:12px;padding-right:12px}
  .page-h h1{font-size:1.3rem}
}
@media print{.topbar,.botbar,.mask,.sheet{display:none!important}}