:root{
  --paper:#ECEEF0; --surface:#F8F9FA; --ink:#1F2430; --muted:#5E6573;
  --grid:#D9A39C; --seal:#B83A2E; --lamp:#D98C1F; --line:#CDD1D6;
  --outline:#DDE0E4; --stroke:#1F2430; --drawing:#3A4254;
  --cell-0:#DADDE1;
  --zh:"LXGW WenKai TC","Kaiti TC","STKaiti","KaiTi","Songti SC",serif;
  --ui:"Source Sans 3",system-ui,-apple-system,"Segoe UI",sans-serif;
  color-scheme:light;
}
@media (prefers-color-scheme:dark){
  :root:not([data-theme="light"]){
    --paper:#151922; --surface:#1E2330; --ink:#ECE8E1; --muted:#9AA1AE;
    --grid:#6B3A36; --seal:#E0574A; --lamp:#F0A93A; --line:#2E3442;
    --outline:#2F3545; --stroke:#ECE8E1; --drawing:#B9BFCC; --cell-0:#262C39;
    color-scheme:dark;
  }
}
:root[data-theme="dark"]{
  --paper:#151922; --surface:#1E2330; --ink:#ECE8E1; --muted:#9AA1AE;
  --grid:#6B3A36; --seal:#E0574A; --lamp:#F0A93A; --line:#2E3442;
  --outline:#2F3545; --stroke:#ECE8E1; --drawing:#B9BFCC; --cell-0:#262C39;
  color-scheme:dark;
}
:root{box-sizing:border-box;padding-top:env(safe-area-inset-top,0px);padding-bottom:env(safe-area-inset-bottom,0px)}
*,*::before,*::after{box-sizing:inherit}
html{height:100%;scroll-padding-top:env(safe-area-inset-top,0px);background:var(--paper)}
body{margin:0;min-height:100%;background:var(--paper);color:var(--ink);font-family:var(--ui);font-size:17px;line-height:1.45;-webkit-tap-highlight-color:transparent}
button{font:inherit;color:inherit;cursor:pointer}
button:focus-visible,select:focus-visible,input:focus-visible{outline:2px solid var(--lamp);outline-offset:2px}
.app{max-width:440px;margin:0 auto;padding:12px 18px 28px}
.hidden{display:none!important}

/* Home */
.top{display:flex;align-items:center;justify-content:space-between;height:44px}
.brand{font-family:var(--zh);font-size:22px;font-weight:700;letter-spacing:.02em}
.brand small{font-family:var(--ui);font-weight:400;font-size:14px;color:var(--muted);margin-left:6px}
.iconbtn{width:44px;height:44px;border:0;background:none;border-radius:50%;display:grid;place-items:center;color:var(--muted)}
.iconbtn svg{width:22px;height:22px}
.hero{margin:28px 0 8px;display:flex;align-items:flex-end;gap:16px}
.hero .big{font-family:var(--zh);font-size:84px;line-height:.9;font-weight:700}
.hero .meta{padding-bottom:6px}
.hero h1{margin:0;font-size:22px;line-height:1.2}
.hero p{margin:2px 0 0;color:var(--muted);font-size:15px}
.today{margin:26px 0 18px;font-size:19px}
.today b{font-variant-numeric:tabular-nums}
.primary{display:block;width:100%;min-height:54px;border:0;border-radius:14px;background:var(--seal);color:#fff;font-weight:700;font-size:18px}
.primary:active{transform:translateY(1px)}
.mosaic-wrap{margin-top:34px}
.mosaic-wrap h2{font-size:15px;font-weight:600;margin:0 0 10px;color:var(--muted)}
.mosaic{display:grid;grid-template-columns:repeat(15,1fr);gap:3px}
.mosaic i{aspect-ratio:1;border-radius:2px;background:var(--cell-0)}
.legend{display:flex;gap:14px;margin-top:10px;font-size:13px;color:var(--muted);flex-wrap:wrap}
.legend span{display:inline-flex;align-items:center;gap:5px}
.legend i{width:10px;height:10px;border-radius:2px;display:inline-block}
.note{margin-top:30px;font-size:14px;color:var(--muted)}

/* Settings */
.sheet{position:fixed;inset:0;background:rgba(10,12,18,.45);display:flex;align-items:flex-end;justify-content:center;z-index:20}
.sheet .panel{background:var(--surface);width:100%;max-width:440px;border-radius:18px 18px 0 0;padding:20px 20px calc(24px + env(safe-area-inset-bottom,0px))}
.panel h2{margin:0 0 14px;font-size:20px}
.row{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:12px 0;border-top:1px solid var(--line)}
.row label{flex:1}
.row small{display:block;color:var(--muted);font-size:13px}
.seg{display:flex;border:1px solid var(--line);border-radius:10px;overflow:hidden}
.seg button{border:0;background:none;padding:8px 11px;font-size:15px;min-width:44px}
.seg button[aria-pressed="true"]{background:var(--ink);color:var(--surface)}
.switch{width:52px;height:32px;border-radius:16px;border:0;background:var(--line);position:relative}
.switch::after{content:"";position:absolute;top:3px;left:3px;width:26px;height:26px;border-radius:50%;background:var(--surface);transition:left .15s}
.switch[aria-checked="true"]{background:var(--seal)}
.switch[aria-checked="true"]::after{left:23px}
.textbtn{border:0;background:none;color:var(--seal);font-weight:600;padding:10px 0}
.done{margin-top:16px;width:100%;min-height:48px;border-radius:12px;border:1px solid var(--line);background:none;font-weight:600}

/* Study */
.studybar{display:flex;align-items:center;justify-content:space-between;height:44px}
.left{color:var(--muted);font-size:15px;font-variant-numeric:tabular-nums}
.barright{display:flex;align-items:center;gap:14px}
.prevbtn{border:0;background:none;color:var(--seal);font-weight:600;font-size:15px;min-height:44px;padding:0 4px}
.prevbtn:disabled{color:var(--muted);opacity:.45}
.prevchar{font-family:var(--zh);font-size:88px;line-height:1.1;text-align:center}
.prevmeta{text-align:center;margin-bottom:6px}
.prevmeta .pinyin{font-size:22px}
.prevnote{text-align:center;color:var(--muted);font-size:14px;margin:8px 0 0}
.prompt{text-align:center;margin:6px 0 10px;min-height:96px}
.tag{display:inline-block;font-size:13px;font-weight:600;color:var(--seal);margin-bottom:2px}
.pinyin{font-size:28px;font-weight:600;line-height:1.2}
.meaning{color:var(--muted);font-size:17px}
.slots{display:flex;justify-content:center;gap:8px;margin:10px 0 14px}
.slot{width:48px;height:48px;border:1.5px solid var(--line);border-radius:8px;display:grid;place-items:center;font-family:var(--zh);font-size:34px;line-height:1;color:var(--ink);background:var(--surface)}
.slot.current{border-color:var(--seal)}
.slot.ghost{color:var(--muted);opacity:.55}
.pad{position:relative;margin:0 auto;aspect-ratio:1;width:100%;max-width:380px;background:var(--surface);border-radius:6px;touch-action:none;user-select:none;-webkit-user-select:none}
.pad svg.grid{position:absolute;inset:0;width:100%;height:100%;pointer-events:none}
.pad .writer{position:absolute;inset:0}
.pad svg.hintlayer{position:absolute;inset:0;width:100%;height:100%;pointer-events:none}
.pad svg.hintlayer path{fill:var(--lamp);opacity:.55}
.pad svg.raw{position:absolute;inset:0;width:100%;height:100%;pointer-events:none;transition:opacity .3s}
.pad svg.raw path{fill:none;stroke:var(--drawing);stroke-linecap:round;stroke-linejoin:round;transition:opacity .25s,stroke .1s}
.pad svg.raw path.bad{stroke:var(--seal);opacity:0}
.stamp{position:absolute;right:10px;top:10px;width:58px;height:58px;border:3px solid var(--seal);border-radius:8px;color:var(--seal);font-family:var(--zh);font-weight:700;font-size:30px;display:grid;place-items:center;transform:rotate(-8deg) scale(1.4);opacity:0;transition:transform .18s ease-out,opacity .18s ease-out;pointer-events:none}
.stamp.on{opacity:.9;transform:rotate(-8deg) scale(1)}
.tools{display:flex;gap:8px}
.bottom{display:flex;gap:8px;margin-top:14px;align-items:stretch}
.mid{flex:1;min-width:0}
.nav{flex:none;width:46px;min-height:52px;border-radius:12px;border:1px solid var(--line);background:var(--surface);display:grid;place-items:center;color:var(--ink);padding:0}
.nav svg{width:22px;height:22px}
.nav:disabled{opacity:.35}
.viewing .pad{opacity:.92}
.tools button{flex:1;min-height:52px;border-radius:12px;border:1px solid var(--line);background:var(--surface);font-weight:600}
.tools button:disabled{opacity:.4}
.tools button.cont{background:var(--ink);color:var(--surface);border-color:var(--ink)}
.phase{display:flex;justify-content:center;gap:6px;margin-top:6px}
.phase i{width:22px;height:5px;border-radius:3px;background:var(--line)}
.phase i.lost{background:transparent;box-shadow:inset 0 0 0 1.5px var(--seal)}
.phase i.on{background:var(--seal)}
.grades{display:grid;grid-template-columns:repeat(4,1fr);gap:6px}
.grades button{min-height:52px;border-radius:12px;border:1px solid var(--line);background:var(--surface);font-weight:600;font-size:14px;line-height:1.1;padding:4px 2px}
.grades button small{display:block;font-weight:400;color:var(--muted);font-size:12px;margin-top:2px}
.grades button.rec{border:2px solid var(--seal)}
.hintline{text-align:center;font-size:14px;color:var(--muted);margin-top:10px;min-height:20px}

/* Summary */
.summary{text-align:center;padding-top:60px}
.summary .big{font-family:var(--zh);font-size:96px;line-height:1;color:var(--seal)}
.summary h1{font-size:26px;margin:18px 0 6px}
.summary p{color:var(--muted);margin:0 0 30px}
@media (prefers-reduced-motion:reduce){.stamp{transition:none}}