:root{--bg:#f3f1ec;--ink:#1d1c1a;--muted:#6b675f;--panel:#ffffff;--line:#d9d4ca;--accent:#b0451f;--base:#1c7ed6;--top:#e8590c;--ok:#2b8a3e;--warn:#c92a2a;--soft:#ebe7df;--unsure:#e67700}
@media (prefers-color-scheme: dark){:root:not([data-theme="light"]){--bg:#1a1917;--ink:#ece8df;--muted:#a39d91;--panel:#242320;--line:#3b3934;--accent:#e0704a;--base:#4dabf7;--top:#ff922b;--ok:#69db7c;--warn:#ff6b6b;--soft:#2e2c28;--unsure:#ffa94d}}
:root[data-theme="dark"]{--bg:#1a1917;--ink:#ece8df;--muted:#a39d91;--panel:#242320;--line:#3b3934;--accent:#e0704a;--base:#4dabf7;--top:#ff922b;--ok:#69db7c;--warn:#ff6b6b;--soft:#2e2c28;--unsure:#ffa94d}
*{box-sizing:border-box}
[hidden]{display:none!important}
html,body{margin:0;height:100%}
body{background:var(--bg);color:var(--ink);font-family:"IBM Plex Sans",system-ui,sans-serif;font-size:15px;line-height:1.35;display:flex;flex-direction:column;height:100dvh;overflow:hidden;-webkit-tap-highlight-color:transparent;overscroll-behavior:none}
button{font:inherit;font-weight:600;font-size:15px;padding:10px 14px;border-radius:8px;border:1px solid var(--line);background:var(--panel);color:var(--ink);cursor:pointer;touch-action:manipulation}
button:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
button:disabled{opacity:.45;cursor:default}
button.primary{background:var(--accent);color:#fff;border-color:var(--accent)}
button.quiet{background:transparent}
button.on{background:var(--ok);color:#fff;border-color:var(--ok)}
.mono{font-family:"IBM Plex Mono",monospace}

/* header */
#top{flex:none;display:flex;align-items:center;justify-content:space-between;gap:8px;padding:6px 16px;border-bottom:1px solid var(--line);background:var(--panel);padding-top:max(6px,env(safe-area-inset-top))}
#top .brand{border:0;background:transparent;font-weight:700;font-size:16px;padding:6px 0}
#top .user{font-size:14px;padding:6px 12px;border-radius:20px;background:var(--soft);border-color:transparent;max-width:60vw;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.net{font-family:"IBM Plex Mono",monospace;font-size:12px;color:var(--warn)}

.screen{flex:1;min-height:0}
/* home */
#home{overflow-y:auto;padding:16px;width:100%;max-width:960px;margin:0 auto;-webkit-overflow-scrolling:touch}
.intro{color:var(--muted);margin:0 0 14px;font-size:14px}
.cards{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:12px;margin-bottom:18px}
.card{background:var(--panel);border:1px solid var(--line);border-radius:12px;padding:14px;display:flex;flex-direction:column;gap:8px;text-align:left;cursor:pointer;font-weight:400}
.card:hover{border-color:var(--accent)}
.card:disabled{cursor:default}
.card h3{margin:0;font-size:19px}
.card .desc{color:var(--muted);font-size:14px;margin:0}
.card .nums{font-family:"IBM Plex Mono",monospace;font-size:13px;color:var(--muted);display:flex;justify-content:space-between;gap:8px;flex-wrap:wrap}
.card .nums b{color:var(--ink)}
.card .prog{height:5px;background:var(--line);border-radius:3px;overflow:hidden}
.card .prog i{display:block;height:100%;background:var(--ok);width:0}
.card .go{align-self:flex-start;margin-top:4px}
.card svg{width:100%;height:80px;display:block}
details.help{background:var(--panel);border:1px solid var(--line);border-radius:12px;padding:10px 14px;margin-bottom:10px}
details.help summary{cursor:pointer;font-weight:600;font-size:15px}
details.help .body{display:flex;gap:16px;align-items:flex-start;margin-top:10px;flex-wrap:wrap}
details.help .body svg{flex:none;width:150px;height:auto;border:1px solid var(--line);border-radius:8px;background:var(--bg)}
details.help ol,details.help ul{margin:0;padding-left:20px;font-size:14px;flex:1 1 220px}
details.help li{margin-bottom:4px}
details.help kbd{font-family:"IBM Plex Mono",monospace;font-size:12px;border:1px solid var(--line);border-bottom-width:2px;border-radius:4px;padding:0 5px;background:var(--soft)}
#helps{margin-bottom:30px}

/* work */
#work{display:flex;flex-direction:column;overflow:hidden}
#workTop{flex:none;padding:6px 12px;display:flex;justify-content:space-between;align-items:baseline;gap:10px;background:var(--panel);border-bottom:1px solid var(--line)}
.prompt{font-weight:600;font-size:15px;min-height:20px}
.prompt .step{color:var(--accent);font-family:"IBM Plex Mono",monospace;margin-right:6px}
.prompt .dot{display:inline-block;width:11px;height:11px;border-radius:50%;margin-right:6px;vertical-align:-1px}
.meta{font-family:"IBM Plex Mono",monospace;font-size:11px;color:var(--muted);white-space:nowrap;flex:none}
.meta .ok{color:var(--ok)}
#workBody{flex:1;min-height:0;display:flex}
#stage{flex:1;min-width:0;min-height:0;position:relative;background:#000;overflow:hidden;touch-action:none;user-select:none;-webkit-user-select:none}
#cv{position:absolute;inset:0;display:block;cursor:crosshair;touch-action:none}
#lens{position:absolute;left:0;top:0;box-sizing:content-box;border-radius:14px;border:2px solid #fff;box-shadow:0 2px 14px rgba(0,0,0,.6);pointer-events:none;display:none;background:#000}
#zoomBox{position:absolute;right:8px;top:8px;display:flex;flex-direction:column;gap:4px}
#zoomBox button{width:34px;height:34px;padding:0;border-radius:8px;background:rgba(255,255,255,.85);color:#111;border-color:transparent;font-size:18px;line-height:1}
#hint{position:absolute;left:8px;top:8px;background:rgba(0,0,0,.72);color:#ffd43b;font-weight:600;font-size:13px;padding:5px 10px;border-radius:8px;pointer-events:none;z-index:2}
#loading,#finished{position:absolute;inset:0;display:flex;align-items:center;justify-content:center;color:#fff;font-size:16px;background:rgba(0,0,0,.55);text-align:center;padding:20px;flex-direction:column;gap:12px}
#side{flex:none;width:290px;overflow:auto;border-left:1px solid var(--line);background:var(--panel);padding:10px 12px;display:flex;flex-direction:column;gap:8px}
#side > *,#side .col > *{flex:none}   /* an overflowing flex column must not shrink the schematic to nothing */
#side .cur{font-weight:600;font-size:14px}
#side .curHint{font-size:13px;color:var(--muted)}
#side .warnZoom{font-size:12px;color:var(--accent);background:var(--soft);border-radius:6px;padding:4px 8px}
#side .grp{font-size:11px;letter-spacing:.06em;text-transform:uppercase;color:var(--muted);margin-top:6px;border-bottom:1px solid var(--line);padding-bottom:2px}
#side .pt{display:flex;align-items:center;gap:8px;padding:4px 6px;border-radius:6px;cursor:pointer;font-size:13px;border:1px solid transparent;background:transparent;color:var(--ink);font-weight:400;text-align:left;width:100%}
#side .pt.cur{border-color:var(--accent);background:var(--soft);font-weight:600}
#side .pt .st{font-family:"IBM Plex Mono",monospace;width:16px;text-align:center;flex:none}
.num{display:inline-block;min-width:20px;height:20px;line-height:20px;border-radius:10px;text-align:center;font:700 12px "IBM Plex Mono",monospace;background:var(--soft);color:var(--ink);flex:none;padding:0 4px;margin-right:2px}
#side .pt.cur .num,.num.cur{background:#ffd43b;color:#000}
#side .cur .num.cur{margin-right:8px;vertical-align:1px}
#side .pt.done .num{color:var(--ok)} #side .pt.nv .num{color:var(--muted)}
#side .pt.done .st{color:var(--ok)} #side .pt.nv .st{color:var(--muted)} #side .pt.unsure .st,#side .pt.unsure .num{color:var(--unsure);font-weight:700}
#side svg{width:100%;max-width:190px;height:auto;align-self:center;background:var(--bg);border:1px solid var(--line);border-radius:8px}
#strip{flex:none;display:flex;gap:2px;padding:6px 12px 2px;background:var(--panel);align-items:flex-end;height:30px}
#strip .seg{flex:1;height:8px;background:var(--line);border-radius:2px;position:relative;min-width:3px}
#strip .seg.done{background:var(--ok)} #strip .seg.nv{background:var(--muted);opacity:.45}
#strip .seg.cur{outline:2px solid var(--accent);outline-offset:1px}
#strip .seg.bounce::before,#strip .seg.impact::before{content:"";position:absolute;left:50%;top:-10px;transform:translateX(-50%);width:0;height:0;border-left:5px solid transparent;border-right:5px solid transparent;border-top:8px solid var(--base)}
#strip .seg.impact::before{border-top-color:var(--top)}
#strip .seg.bounce.impact::after{content:"";position:absolute;left:50%;top:-16px;transform:translateX(-50%);width:0;height:0;border-left:5px solid transparent;border-right:5px solid transparent;border-top:6px solid var(--top)}
#bar{flex:none;display:flex;gap:8px;padding:8px 12px;flex-wrap:wrap;background:var(--panel);border-top:1px solid var(--line);padding-bottom:max(8px,env(safe-area-inset-bottom))}
#bar button{flex:1 1 auto;min-width:70px}
#bar button.wide{flex:2 1 160px}
.kb{display:inline-block;margin-left:7px;font:500 10px/1 "IBM Plex Mono",monospace;padding:2px 5px 1px;border:1px solid var(--line);border-bottom-width:2px;border-radius:4px;opacity:.75;vertical-align:1px;color:inherit}
button.primary .kb,button.on .kb{border-color:rgba(255,255,255,.6)}
@media (hover:none) and (pointer:coarse){.kb{display:none}}
#bar .sp{flex:0 0 100%;height:0}

@media (max-width:720px){
  #workBody{flex-direction:column}
  #side{width:auto;border-left:0;border-top:1px solid var(--line);max-height:40%;flex-direction:row;padding:8px 10px;gap:10px}
  #side svg{width:138px;max-width:138px;flex:none;align-self:flex-start}
  #side .col{flex:1 1 auto;min-width:0;display:flex;flex-direction:column;gap:5px;overflow:auto}
  #side .list{display:flex;flex-wrap:wrap;gap:4px}
  #side .grp{width:100%;margin-top:2px}
  #side .pt{width:auto;padding:4px 7px 4px 4px;background:var(--soft);border-color:var(--line);font-size:12px;gap:5px}
  #side .pt .st{width:12px}
  #side .pt.cur{border-color:var(--accent);background:var(--accent);color:#fff}
  #side .pt.cur .st{color:#fff}
  #side .pt .num{background:var(--panel)}
  #workTop{flex-direction:column;gap:2px;align-items:stretch}
  .prompt{font-size:14px}
  .meta{white-space:normal}
  #bar button{padding:11px 8px;font-size:14px}
}
@media (min-width:721px){
  #side .col{display:contents}
  #side .list{display:flex;flex-direction:column;gap:2px}
}

/* modal / toast */
.modal{position:fixed;inset:0;background:rgba(0,0,0,.55);display:flex;align-items:center;justify-content:center;padding:20px;z-index:20}
.modalBox{background:var(--panel);border-radius:14px;padding:22px;max-width:380px;width:100%;display:flex;flex-direction:column;gap:12px}
.modalBox h2{margin:0;font-size:22px}
.modalBox .hint{margin:0;color:var(--muted);font-size:14px}
.modalBox input{font:inherit;font-size:17px;padding:12px;border:1px solid var(--line);border-radius:8px;background:var(--bg);color:var(--ink);width:100%}
#toast{position:fixed;left:50%;bottom:90px;transform:translateX(-50%);background:var(--ink);color:var(--bg);padding:12px 18px;border-radius:12px;font-weight:600;font-size:16px;z-index:30;box-shadow:0 6px 24px rgba(0,0,0,.35);max-width:90vw;text-align:center}
#toast.big{font-size:22px;padding:18px 28px;background:var(--ok);color:#fff}
@media (prefers-reduced-motion: reduce){*{transition:none!important;animation:none!important}}