:root{
  /* ink3 is the smallest type on the page; it has to clear 4.5:1 on white. */
  --ink:#1a2430; --ink2:#516678; --ink3:#647385; --ink4:#5a6974;
  /* One source of truth for the two-column width, so the panels below the
     stage line up with it instead of running the full window. */
  --rail:clamp(270px,25vw,340px);
  --boardmax:calc((100svh - 205px) * .92);
  --stage-w:calc(var(--boardmax) + var(--rail) + 16px);
  --page:#eceff2; --card:#fff; --line:#d6dee5; --line2:#c2ccd6;
  /* --live fills bars and the dark board; --live-ink is the readable text version. */
  --accent:#3f6d95; --live:#2ea36a; --live-ink:#1f7d50; --warn:#c2762a; --bad:#b8412b;
  --board-bg:#11181f; --board-ink:#e8eef4; --board-dim:#8798a8;
  font-family:system-ui,-apple-system,"PingFang SC",sans-serif;color:var(--ink);background:var(--page);font-synthesis:none;
}
*{box-sizing:border-box}
body{margin:0;padding-bottom:28px}
h1,h2{margin:0}
code{font-family:ui-monospace,Menlo,monospace;font-size:.92em;background:#e2e8ee;padding:1px 4px;border-radius:3px}

/* ---------- top bar ---------- */
.topbar{display:flex;align-items:center;gap:14px;padding:10px 20px;background:var(--card);border-bottom:1px solid var(--line);flex-wrap:wrap}
.back{color:var(--ink2);text-decoration:none;font-size:13px;white-space:nowrap}
.badge{font-size:10px;letter-spacing:.14em;color:var(--ink3);border:1px solid var(--line2);border-radius:20px;padding:5px 11px;margin-left:auto;white-space:nowrap}
.picker{display:flex;align-items:center;gap:9px;flex:1;min-width:280px;font-size:12px;color:var(--ink2)}
.picker select{font:13px system-ui;padding:6px 9px;border:1px solid var(--line2);border-radius:8px;background:#fff;color:var(--ink);flex:1;min-width:0;max-width:560px}
.toggle{display:inline-flex;align-items:center;gap:6px;cursor:pointer;white-space:nowrap}
input[type=checkbox]{accent-color:var(--accent)}
button{font:14px system-ui;color:var(--ink2);background:#f7fafc;border:1px solid var(--line2);border-radius:10px;padding:7px 12px;cursor:pointer}
button:hover{background:#fff;color:var(--ink)}
button:disabled{opacity:.4;cursor:default}
button.small{font-size:12px;padding:5px 10px;border-radius:8px}
button:focus-visible,a:focus-visible,select:focus-visible,input:focus-visible,.steps:focus-visible{outline:3px solid var(--accent);outline-offset:2px}
/* Reachable by screen readers, invisible on screen. */
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip-path:inset(50%);white-space:nowrap;border:0}

/* ---------- stage: board left, live rail right ---------- */
/* The board is a portrait hexagon, so its card is height-bound: cap the board
   column near the height it can actually use and centre the pair, instead of
   stretching a card whose middle 40% would be empty. */
.stage{display:grid;grid-template-columns:minmax(0,var(--boardmax)) var(--rail);
  gap:16px;padding:16px 20px 0;align-items:stretch;justify-content:center}
.board-col{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:14px;display:flex;flex-direction:column;min-width:0}
/* The canvas is taken out of flow on purpose. Left in flow, `height:100%`
   degrades to auto during intrinsic sizing and the box falls back to the
   canvas *attribute* ratio — which resize() writes from this very box. That
   loop let a detour through a short window permanently inflate the card. */
.board-wrap{flex:1;width:100%;position:relative;min-height:clamp(340px,calc(100svh - 235px),760px)}
canvas{position:absolute;inset:0;width:100%;height:100%;display:block}
/* Only surfaces when a run's JSON can't be read — otherwise it takes no space. */
.notice{margin:10px 0 0;text-align:center;font-size:13px;line-height:1.6;color:var(--bad)}

/* 谁在玩：棋盘正上方的身份横幅 */
.who{display:flex;align-items:baseline;justify-content:space-between;gap:12px;flex-wrap:wrap;
  padding:0 2px 10px;margin-bottom:10px;border-bottom:1px solid var(--line)}
.who-id{display:flex;align-items:baseline;gap:10px;flex-wrap:wrap;min-width:0}
.who-id b{font-size:19px;font-weight:700;letter-spacing:-.01em}
/* Agents self-report free text, so assume the worst: a slug or user-agent
   string with no spaces has to break rather than push the page sideways. */
.who-agent{font-size:13px;color:var(--accent);font-weight:600;min-width:0;overflow-wrap:anywhere}
/* Hang the separator off the model name. As ::before on the agent it wrapped
   to the start of the next line and read like a bullet. */
.who-id:has(.who-agent:not(:empty)) b::after{content:'·';margin-left:10px;color:var(--ink3);font-weight:400}
.who-level{font-size:11.5px;color:var(--ink3);font-variant-numeric:tabular-nums}

.rail{display:flex;flex-direction:column;gap:16px;min-width:0;min-height:0}

/* ---------- scoreboard: a vertical panel beside the board ---------- */
.scoreboard{background:var(--board-bg);color:var(--board-ink);border-radius:14px;padding:16px;
  display:flex;flex-direction:column;gap:13px;flex:0 0 auto;transition:opacity .2s}
/* Rewound: the clock and the totals belong to the whole run, so they no longer
   describe the board sitting right next to them. Say so instead of lying. */
.scoreboard.rewound{opacity:.55}
@media(prefers-reduced-motion:reduce){.scoreboard{transition:none}}
.scoreboard .clock{display:flex;flex-direction:column;gap:4px;min-width:0}
.scoreboard .k{font-size:10px;letter-spacing:.12em;color:var(--board-dim);text-transform:uppercase;white-space:nowrap}
.scoreboard b{font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-variant-numeric:tabular-nums;font-weight:600;line-height:1;font-size:19px}
.scoreboard small{font-size:11px;color:var(--board-dim);margin-left:4px;font-family:ui-monospace,Menlo,monospace}
.clock.primary b{font-size:clamp(32px,3.1vw,42px);letter-spacing:-.02em}
.clock.think b{font-size:23px;color:#f0c674}
.tick.hot{color:#ffcf6b}
/* Each readout is a wrapping row: the label owns a line, the number keeps its
   suffix beside it. Stacking all three (a flex column blockifies `inline`)
   cost a third line per cell and made the panel needlessly tall. */
.scoreboard .stats{display:grid;grid-template-columns:1fr 1fr;gap:12px 12px;border-top:1px solid #27323d;padding-top:13px}
.scoreboard .cell{display:flex;flex-wrap:wrap;align-items:baseline;min-width:0}
.scoreboard .cell .k{flex:0 0 100%;margin-bottom:4px}
.scoreboard .bar{height:5px;background:#27323d;border-radius:3px;overflow:hidden}
.scoreboard .bar i{display:block;height:100%;background:var(--live);width:0;transition:width .3s}
.pill{align-self:flex-start;font-size:12px;font-weight:600;letter-spacing:.04em;padding:7px 14px;border-radius:20px;white-space:nowrap;background:#25303b;color:var(--board-dim)}
.pill.rewound{background:#2b3742;color:#c7d4de}
.pill.playing{background:rgba(46,163,106,.18);color:#5ed69b}
.pill.playing::before{content:'●';margin-right:6px;animation:blink 1.4s infinite}
.pill.cleared{background:rgba(46,163,106,.25);color:#7fe6b4}
.pill.gaveup{background:rgba(184,65,43,.22);color:#ff9b85}
.pill.budget{background:rgba(194,118,42,.22);color:#f3c98a}
@keyframes blink{50%{opacity:.25}}

/* ---------- live feed ---------- */
.feed-col{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:14px;display:flex;flex-direction:column;flex:1 1 auto;min-height:200px}
/* The button and the live state are siblings of the heading, not inside it —
   nested, they became part of the heading's accessible name. */
.feed-head{display:flex;align-items:center;gap:8px;flex-wrap:wrap;margin-bottom:10px}
.feed-col h2{font-size:11px;letter-spacing:.16em;color:var(--ink3);text-transform:uppercase}
.feed-state{font-size:10.5px;letter-spacing:.02em;color:var(--live-ink);font-weight:600}
.back-live{margin-left:auto;color:var(--accent);border-color:var(--accent)}
.steps{margin:0;padding:0;list-style:none;overflow-y:auto;flex:1 1 0;min-height:0;font-size:12.5px;counter-reset:step}
.steps li{padding:8px 10px 8px 32px;border-bottom:1px solid #eef2f5;position:relative;cursor:pointer;line-height:1.55;counter-increment:step}
.steps li::before{content:counter(step);position:absolute;left:8px;top:8px;font-family:ui-monospace,Menlo,monospace;font-size:10.5px;color:var(--ink3)}
.steps li:last-child{border-bottom:none}
.steps li.lead{border-top:1px solid var(--line);margin-top:2px}
.steps li:first-child.lead{border-top:none;margin-top:0}
.steps li b{font-weight:600}
.steps li i{display:block;color:var(--ink2);font-style:normal;font-size:11.5px;margin-top:2px}
.steps li em{float:right;margin-left:8px;font-style:normal;font-size:10.5px;color:var(--accent);background:#eaf1f7;border-radius:9px;padding:1px 7px;font-variant-numeric:tabular-nums;font-weight:600}
.steps li.current{background:#eaf1f7;box-shadow:inset 3px 0 0 var(--accent)}
.steps li:hover{background:#f2f6f9}

/* ---------- details below ---------- */
.details{display:grid;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));gap:14px;padding:16px 20px 0;
  width:100%;max-width:calc(var(--stage-w) + 40px);margin-inline:auto}
.panel{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:14px}
.panel h2{font-size:11px;letter-spacing:.16em;color:var(--ink3);text-transform:uppercase;margin-bottom:10px}
.kv{margin:0;font-size:12.5px}
.kv>div{display:flex;justify-content:space-between;gap:10px;padding:5px 0;border-bottom:1px dashed #e4eaef}
.kv>div:last-child{border-bottom:none}
.kv dt{color:var(--ink3)}
.kv dd{margin:0;font-variant-numeric:tabular-nums;text-align:right;color:var(--ink);font-weight:600}
.kv .giveup dd{color:var(--bad);text-align:left;font-weight:400}

footer{text-align:center;margin:20px auto 0;max-width:760px;padding:0 20px;font-size:11px;color:var(--ink4);line-height:1.7}

/* The rail needs ~260px to stay readable; below that it goes under the board,
   where the clock turns into a wide two-up row instead of a tall column. */
@media(max-width:820px){
  .stage{grid-template-columns:1fr;align-items:start}
  /* Stacked, the card is full width, so the board should be tall enough to
     use it — 62vw left a 603px canvas holding a 330px board. */
  .board-wrap{min-height:clamp(280px,min(96vw,64svh),680px)}
  .scoreboard{display:grid;grid-template-columns:auto minmax(0,1fr);align-items:center;gap:12px 18px}
  .scoreboard .clock.primary{grid-column:1}
  .scoreboard .clock.think{grid-column:2}
  .clock.primary b{font-size:38px}
  .scoreboard .stats{grid-column:1 / -1;grid-template-columns:repeat(4,minmax(0,1fr))}
  .scoreboard .bar,.pill{grid-column:1 / -1}
  /* Stacked, the rail's height comes from its content, so `flex:1 1 0` resolved
     to zero and the list vanished — taking the only way to replay a step with
     it. Give the list its own height instead of a share of a leftover. */
  .feed-col{min-height:0}
  .steps{flex:0 0 auto;max-height:min(340px,52svh)}
}
@media(max-width:520px){
  .topbar{padding:8px 12px;gap:8px}
  .picker{min-width:100%;order:3}
  .picker select{max-width:none}
  .stage,.details{padding-left:12px;padding-right:12px}
  .board-col,.feed-col,.panel{padding:12px}
  .scoreboard{padding:14px;gap:11px 14px}
  .clock.primary b{font-size:34px}
  .clock.think b{font-size:20px}
  .scoreboard .stats{grid-template-columns:1fr 1fr}
  .who-id b{font-size:17px}
}
/* Below ~400px the two clocks no longer fit on one row: 「本步思考」 gets about
   94px and its mono value needs 96. Stack them rather than clip the digits. */
@media(max-width:400px){
  .scoreboard .clock.primary,.scoreboard .clock.think{grid-column:1 / -1}
  .clock.think b{font-size:22px}
}
@media(prefers-reduced-motion:reduce){.pill.playing::before{animation:none}.scoreboard .bar i{transition:none}}