:root{
  --bg:#050810; --panel:#0c1220; --line:#1a2540; --line2:#2a3852;
  --gold:#af915f; --gold-hi:#fce1b6; --text:#c3cede; --muted:#5a6b87; --muted2:#8b9bb8;
  --red:#f87171; --green:#4ade80; --felt:#0d3b2e;
}
*{box-sizing:border-box}
html,body{margin:0;background:var(--bg);color:var(--text);font-family:Inter,"Noto Sans SC","PingFang SC","Microsoft YaHei",system-ui,sans-serif;-webkit-text-size-adjust:100%;line-height:1.55}
html[lang="zh-Hans"] body{line-height:1.75}
button,select,input{font:inherit;color:inherit}
button{cursor:pointer;touch-action:manipulation}
a{color:var(--gold)}
.mono{font-family:"JetBrains Mono",ui-monospace,monospace}
.display{font-family:Marcellus,"Noto Serif SC",Georgia,serif}
.zh{font-family:"Noto Sans SC","PingFang SC","Microsoft YaHei",sans-serif}
[hidden]{display:none!important}
:focus-visible{outline:2px solid var(--gold-hi);outline-offset:2px}
.skip{position:absolute;left:-999px;top:0;background:var(--gold);color:#0c1220;padding:8px 12px;z-index:100}
.skip:focus{left:8px;top:8px}

/* header */
header.top{border-bottom:1px solid var(--line);background:rgba(5,8,16,.92);position:sticky;top:0;z-index:30;backdrop-filter:blur(6px)}
.top-in{max-width:1080px;margin:0 auto;padding:10px 16px;display:flex;align-items:center;gap:12px}
.logo{width:40px;height:40px;border:1px solid var(--gold);display:flex;align-items:center;justify-content:center;color:var(--gold);font-size:22px;flex:none}
.brand h1{margin:0;font-size:18px;letter-spacing:.06em;color:#fff;line-height:1;font-weight:400}
.brand h1 b{color:var(--gold);font-weight:400}
.brand small{display:block;margin-top:4px;font-size:9px;letter-spacing:.28em;text-transform:uppercase;color:var(--muted)}
.langbox{margin-left:auto;display:flex;align-items:center;gap:8px}
.langbox label{font-size:10px;letter-spacing:.18em;text-transform:uppercase;color:var(--muted)}
.langbox select{height:40px;background:var(--panel);border:1px solid var(--gold);color:var(--gold-hi);padding:0 10px;font-size:14px;border-radius:0}
.nav{max-width:1080px;margin:0 auto;padding:0 16px;display:flex;gap:4px;overflow-x:auto;scrollbar-width:none}
.nav::-webkit-scrollbar{display:none}
.nav a{flex:none;padding:10px 14px;font-size:11px;letter-spacing:.16em;text-transform:uppercase;color:var(--muted2);text-decoration:none;border-bottom:2px solid transparent;white-space:nowrap}
.nav a:hover{color:var(--gold-hi)}
.nav a.on{color:var(--gold-hi);border-bottom-color:var(--gold)}
@media (max-width:480px){.langbox label{display:none}}

main{max-width:1080px;margin:0 auto;padding:20px 16px 40px;min-height:70vh;outline:none}
h2{font-family:Marcellus,"Noto Serif SC",Georgia,serif;font-weight:400;color:#fff;margin:0 0 6px;font-size:26px;line-height:1.25}
h3{font-family:Marcellus,"Noto Serif SC",Georgia,serif;font-weight:400;color:#fff;margin:2px 0 6px;font-size:22px}
.lead{color:var(--muted2);margin:0 0 20px;font-size:14px;max-width:70ch}
.card-box{background:var(--panel);border:1px solid var(--line);padding:20px;margin-bottom:12px}
.eyebrow,.lbl{font-size:10px;letter-spacing:.2em;text-transform:uppercase;color:var(--muted2);margin-bottom:8px}
.gold{color:var(--gold-hi)}
.muted{color:var(--muted);font-size:13px}

/* buttons */
.primary,.ghost{display:inline-flex;align-items:center;justify-content:center;text-decoration:none;text-align:center}
.primary{height:52px;padding:0 28px;border:1px solid var(--gold);background:var(--gold);color:#0c1220;font-weight:600;letter-spacing:.12em;text-transform:uppercase;font-size:13px}
.primary:hover{background:var(--gold-hi)}
.primary:disabled{opacity:.45;cursor:not-allowed}
.ghost{min-height:44px;padding:0 16px;border:1px solid var(--line2);background:transparent;color:var(--muted2);font-size:12px;letter-spacing:.1em;text-transform:uppercase}
.ghost:hover{border-color:var(--gold);color:var(--gold-hi)}
.actions{display:flex;flex-wrap:wrap;gap:10px;margin-top:18px}

/* tiles */
svg.tile{width:var(--tw,42px);height:auto;aspect-ratio:60/82;display:block;filter:drop-shadow(0 2px 3px rgba(0,0,0,.5))}
svg.tile text{font-family:"Noto Serif SC","Songti SC","STSong","SimSun",serif;font-weight:600}
svg.tile.sm{--tw:34px} svg.tile.md{--tw:40px} svg.tile.lg{--tw:64px} svg.tile.xl{--tw:104px}
.grp{display:inline-flex;gap:3px;margin:0 10px 10px 0}
.grp.wrap{display:flex;flex-wrap:wrap;gap:6px;margin:0}
.tbtn{position:relative;background:transparent;border:2px solid transparent;border-radius:9px;padding:2px;line-height:0}
.tbtn:hover{border-color:var(--line2)}
.tbtn.sel{border-color:var(--gold);background:rgba(175,145,95,.14)}
.tbtn.right{border-color:var(--green);background:rgba(74,222,128,.12)}
.tbtn.wrongpick{border-color:var(--red);background:rgba(248,113,113,.12)}
.tbtn:disabled{cursor:default}
.badge{position:absolute;right:-4px;top:-6px;background:var(--gold);color:#0c1220;font:700 11px/1 "JetBrains Mono",monospace;border-radius:99px;padding:3px 6px}

/* learn */
.learn{display:grid;gap:16px}
.learn>*{min-width:0}
@media (min-width:860px){.learn{grid-template-columns:260px 1fr;align-items:start}.toc{position:sticky;top:110px}}
.toc{background:var(--panel);border:1px solid var(--line);padding:16px}
.toc-h{font-size:10px;letter-spacing:.24em;text-transform:uppercase;color:var(--gold);margin-bottom:10px}
.meter{height:6px;background:var(--line);border-radius:99px;overflow:hidden}
.meter i{display:block;height:100%;background:var(--gold)}
.toc-p{font-size:12px;color:var(--muted2);margin:6px 0 12px}
.toc-list{display:flex;flex-direction:column}
.toc-list a{display:flex;gap:10px;align-items:center;padding:9px 6px;color:var(--muted2);text-decoration:none;font-size:14px;border-bottom:1px solid rgba(26,37,64,.7)}
.toc-list a:hover{color:var(--gold-hi)}
.toc-list a.on{color:#fff}
.toc-list .num{flex:none;width:24px;height:24px;border:1px solid var(--line2);border-radius:50%;display:flex;align-items:center;justify-content:center;font:500 11px "JetBrains Mono",monospace}
.toc-list a.on .num{border-color:var(--gold);color:var(--gold-hi)}
@media (max-width:859px){
  .toc-list{flex-direction:row;overflow-x:auto;gap:4px;padding-bottom:4px}
  .toc-list a{flex:none;border:1px solid var(--line2);padding:8px 12px;white-space:nowrap}
  .toc-list a.on{border-color:var(--gold)}
}
.lesson{padding:24px}
.lesson h2{font-size:30px;margin-bottom:14px}
.lesson p,.lesson li{font-size:15px;max-width:68ch}
.lesson ul,.lesson ol{padding-left:22px;margin:8px 0 14px}
.lesson li{margin:6px 0}
.lesson b{color:var(--gold-hi);font-weight:600}
.demo{margin:14px 0 18px;padding:16px;background:radial-gradient(ellipse at center,var(--felt) 0%,#0a2a21 100%);border:1px solid var(--line2);border-radius:12px}
.demo-row{display:flex;flex-wrap:wrap;align-items:flex-end}
.demo svg.tile{--tw:clamp(28px,7vw,44px)}
.demo figcaption{font-size:12px;color:#b9d8cb;margin-top:4px}
.tip{border:1px solid var(--gold);background:rgba(175,145,95,.08);padding:12px 14px;margin:14px 0;font-size:14px;max-width:68ch}
.tip-l{display:block;font-size:10px;letter-spacing:.2em;text-transform:uppercase;color:var(--gold);margin-bottom:4px;font-weight:500}
.pager{display:flex;justify-content:space-between;gap:10px;margin-top:26px;padding-top:18px;border-top:1px solid var(--line);flex-wrap:wrap}
.tbl-wrap{overflow-x:auto}
.tbl{width:100%;border-collapse:collapse;font-size:14px}
.tbl th{font-size:10px;letter-spacing:.18em;text-transform:uppercase;color:var(--muted2);text-align:left;font-weight:500}
.tbl th,.tbl td{padding:9px 10px;border-bottom:1px solid rgba(26,37,64,.9);vertical-align:top}
.tbl td.nowrap{white-space:nowrap;color:var(--gold-hi)}

/* tiles page */
.tiles-page{display:grid;gap:12px}
.tile-info{display:flex;gap:20px;align-items:center;position:sticky;top:96px;z-index:5;margin-bottom:0}
.tile-info .big svg.tile{--tw:84px}
.tile-info p{margin:0;font-size:14px;color:var(--text);max-width:60ch}
.tile-groups{display:grid;gap:12px;margin-top:0}
.grp-h{display:flex;justify-content:space-between;gap:10px;flex-wrap:wrap;margin-bottom:10px;font-size:14px;color:#fff}
.grp-h small{color:var(--muted2);font-size:12px}
.tbtn svg.tile{--tw:clamp(34px,8.6vw,48px)}
.tbtn.sm svg.tile{--tw:clamp(28px,7.4vw,38px)}

/* practice */
.modes{display:grid;gap:12px}
@media (min-width:700px){.modes{grid-template-columns:1fr 1fr}}
.mode{display:flex;flex-direction:column;gap:8px;text-align:left;color:inherit;margin:0;min-height:150px}
.mode:hover{border-color:var(--gold)}
.mode-t{font-family:Marcellus,"Noto Serif SC",serif;color:#fff;font-size:22px}
.mode-d{color:var(--muted2);font-size:14px}
.mode-f{margin-top:auto;display:flex;justify-content:space-between;font-size:12px;color:var(--muted2);letter-spacing:.08em;text-transform:uppercase;padding-top:10px}
.mode-f b{color:var(--gold);font-weight:500}
.strip{display:flex;flex-wrap:wrap;gap:6px 18px;align-items:center;font-size:11px;letter-spacing:.1em;text-transform:uppercase;color:var(--muted2);margin:0 0 10px}
.strip b{color:var(--gold-hi);font-weight:500}
.strip .sp{margin-left:auto;min-height:36px;font-size:10px}
.quiz .q{font-family:Marcellus,"Noto Serif SC",serif;font-size:22px;color:#fff;margin:0 0 16px}
.stage{display:flex;justify-content:center;padding:22px 10px;background:radial-gradient(ellipse at center,var(--felt) 0%,#0a2a21 100%);border:1px solid var(--line2);border-radius:14px;margin-bottom:16px}
.stage .grp{margin:0;flex-wrap:wrap;justify-content:center;gap:5px}
.stage.hand svg.tile{--tw:clamp(24px,9vw,40px)}
.opts{display:grid;grid-template-columns:1fr 1fr;gap:10px}
.opts.two{grid-template-columns:1fr 1fr}
@media (max-width:420px){.opts{grid-template-columns:1fr}}
.opt{min-height:54px;padding:10px 14px;background:transparent;border:1px solid var(--line2);color:var(--text);font-size:15px}
.opt:hover:not(:disabled){border-color:var(--gold);color:var(--gold-hi)}
.opt:disabled{cursor:default}
.opt.right{border-color:var(--green);background:rgba(74,222,128,.1);color:#fff}
.opt.wrongpick{border-color:var(--red);background:rgba(248,113,113,.1);color:#fff}
.pal{margin-top:6px}
.prow{display:grid;grid-template-columns:repeat(9,1fr);gap:3px;margin-bottom:6px;max-width:480px}
.prow .tbtn{padding:1px;min-height:44px;display:flex;align-items:center;justify-content:center}
.prow .tbtn svg.tile{--tw:100%;width:100%}
.prow .badge{right:-2px;top:-4px;font-size:10px;padding:2px 5px}
.fb{border-left:4px solid var(--gold)}
.fb.ok{border-left-color:var(--green)} .fb.bad{border-left-color:var(--red)}
.fb>b{display:block;color:#fff;margin-bottom:4px}
.sets{display:flex;flex-wrap:wrap;gap:10px 16px;margin-top:10px}
.set small{display:block;font-size:10px;letter-spacing:.16em;text-transform:uppercase;color:var(--muted2);margin-bottom:4px}
.set .grp{margin:0}
.result{text-align:center}
.score{font-size:64px;color:var(--gold-hi);line-height:1}
.score small{font-size:26px;color:var(--muted2)}
.result .actions{justify-content:center}

/* checker */
.handbox svg.tile{--tw:clamp(24px,8.4vw,36px)}
.handbox{display:flex;flex-wrap:wrap;gap:3px;min-height:56px;padding:10px;background:radial-gradient(ellipse at center,var(--felt) 0%,#0a2a21 100%);border:1px solid var(--line2);border-radius:12px}
.res{margin-top:16px;padding:12px 14px;border:1px solid var(--line2);font-size:14px}
.res.good{border-color:var(--green);background:rgba(74,222,128,.07)}
.res.bad{border-color:#7f2a2a;background:rgba(248,113,113,.06)}
.res>b{color:#fff}
.res .grp{margin-top:8px}

/* glossary */
.search{width:100%;height:44px;background:var(--bg);border:1px solid var(--line2);padding:0 12px;margin-bottom:12px;font-size:15px}
.gl td:first-child{white-space:nowrap}

.foot{max-width:1080px;margin:0 auto;padding:0 16px 40px}
.foot p{margin:0;border-top:1px solid var(--line);padding-top:16px;font-size:12px;color:var(--muted);max-width:80ch}
@media (max-width:600px){
  .tile-info{flex-direction:row;padding:12px;gap:14px}
  .tile-info .big svg.tile{--tw:56px}
  h3{font-size:18px}
  .lesson{padding:18px}
  .lesson h2{font-size:26px}
}
@media (prefers-reduced-motion:reduce){*{animation:none!important;transition:none!important}}