@font-face{font-family:Instrument;src:url('../../assets/fonts/instrument-sans-latin-400-normal.woff2');font-display:swap}
@font-face{font-family:Instrument;src:url('../../assets/fonts/instrument-sans-latin-600-normal.woff2');font-weight:600;font-display:swap}
@font-face{font-family:Anybody;src:url('../../assets/fonts/anybody-var.woff2');font-weight:100 900;font-display:swap}
@font-face{font-family:JetBrains;src:url('../../assets/fonts/jetbrains-mono-latin-400-normal.woff2');font-display:swap}
@font-face{font-family:JetBrains;src:url('../../assets/fonts/jetbrains-mono-latin-500-normal.woff2');font-weight:500;font-display:swap}

:root{--app-accent:#ff8a1f;--accent-text:#ff9d43;--bg:#0b1015;--panel:#111920;--raised:#1d2832;--line:#2b3741;--fg:#ecf0f2;--muted:#a3afb9;--soft:#7d8a95;
  --good:#71d8bd;--warn:#ffc66b;--bad:#ff7a66;--data:#ff8a1f;--data-ink:#241204;--ack:#62d9ef;--ack-ink:#062530;--stage:#0a1117;--stage-line:#1d2a35;--node:#1a242e;--node-edge:#3b4955;
  --font:Instrument,system-ui,sans-serif;--display:Anybody,system-ui,sans-serif;--mono:JetBrains,ui-monospace,monospace}
:root[data-theme=light]{--bg:#f4f2ee;--panel:#fff;--raised:#eeeae4;--line:#d8d3cb;--fg:#1b2933;--muted:#5c6870;--soft:#7a858c;--accent-text:#a64c00;
  --good:#167a62;--warn:#9a6200;--bad:#b8321f;--data:#e56f00;--data-ink:#fff;--ack:#0a84a0;--ack-ink:#fff;--stage:#f8f6f2;--stage-line:#e4ded5;--node:#fff;--node-edge:#b9b1a6}

body{font-family:var(--font);font-size:15px;background:radial-gradient(ellipse at 88% 0,#ff8a1f0d,transparent 40%),var(--bg)}
button{transition:background .15s,border-color .15s;touch-action:manipulation}
button.primary{background:var(--app-accent);color:#241204;border-color:var(--app-accent)}button.primary:hover{background:#ffa24b;border-color:#ffa24b}
button[aria-pressed=true]{border-color:var(--app-accent);background:color-mix(in srgb,var(--app-accent) 12%,var(--panel))}
button:focus-visible,input:focus-visible,select:focus-visible,summary:focus-visible,a:focus-visible,[tabindex]:focus-visible{outline:2px solid var(--app-accent);outline-offset:3px}
input[type=range]{accent-color:var(--app-accent);min-height:36px}
output{color:var(--accent-text);font:500 13px var(--mono)}
.eyebrow{font:10px var(--mono);color:var(--accent-text);letter-spacing:.11em;margin-bottom:9px}
.link-button{background:none;border:0;padding:0;min-height:32px;color:var(--accent-text);font-size:12px;font-weight:600;text-decoration:underline;text-underline-offset:3px}
.link-button:hover{background:none}

/* header + hero */
.app-header{max-width:none;padding:12px max(24px,calc((100vw - 1400px)/2));min-height:70px}
.app-header strong{font-size:12px;letter-spacing:.13em}.app-header strong span{margin-left:12px;color:var(--muted);font:10px var(--mono)}
.app-main{max-width:1440px;padding:38px 24px 28px}
.intro{display:flex;align-items:center;justify-content:space-between;gap:30px;padding:0 0 30px}
.intro h1{font:650 clamp(38px,4.8vw,66px)/1.04 var(--display);letter-spacing:-.045em}.intro h1 span{color:var(--accent-text)}
.intro-note{display:flex;align-items:center;gap:22px;max-width:500px}.intro-note p{color:var(--muted);font-size:14px;line-height:1.7}.intro-note b{color:var(--fg)}
.intro-glyph{width:120px;height:80px;flex:0 0 120px}
.intro-glyph .g-link{fill:none;stroke:var(--line);stroke-width:2.5}
.intro-glyph circle{fill:var(--panel);stroke:var(--accent-text);stroke-width:2.5}
.intro-glyph .g-pkt{fill:var(--data)}.intro-glyph .g-ack{fill:var(--ack)}

/* question cards */
.section-label{display:flex;justify-content:space-between;gap:12px;font:10px var(--mono);letter-spacing:.11em;color:var(--muted);margin-bottom:10px}
.section-label span:first-child{color:var(--accent-text)}
.question-grid{display:grid;grid-template-columns:repeat(6,minmax(0,1fr));gap:10px;margin-bottom:20px}
.question-grid button{text-align:left;min-width:0;padding:14px 15px 15px;background:var(--panel);border-radius:12px;position:relative;display:flex;flex-direction:column;align-items:flex-start;justify-content:flex-start}
.question-grid button[aria-pressed=true]:after{content:'';position:absolute;inset:auto 15px -1px;height:3px;background:var(--app-accent);border-radius:3px}
.question-grid span{display:block;font:9px var(--mono);color:var(--accent-text);letter-spacing:.06em;margin-bottom:9px}
.question-grid strong{font-size:14.5px;line-height:1.3;display:block}
.question-grid small{display:block;margin-top:6px;font-size:11px;line-height:1.45;color:var(--muted);font-weight:400}

/* bench */
.bench{display:grid;grid-template-columns:minmax(0,1fr) 304px;grid-template-areas:'tool tool' 'read read' 'stage side' 'now side' 'queues side';grid-template-rows:auto auto auto auto 1fr;border:1px solid var(--line);border-radius:17px;overflow:clip;background:var(--panel);scroll-margin-top:12px;box-shadow:0 18px 60px #00000022}
.bench:focus{outline:none}
.bench-toolbar{padding:12px 16px;display:flex;align-items:center;justify-content:space-between;gap:12px;border-bottom:1px solid var(--line);flex-wrap:wrap}
.transport{display:flex;gap:8px;flex-wrap:wrap}.transport button{min-height:42px;font-size:12px}
#play{min-width:104px}#playIcon{display:inline-block;width:14px;font-size:11px}
.time-tools{display:flex;align-items:center;gap:14px}
.speed-label{font:10px var(--mono);letter-spacing:.08em;color:var(--muted);text-transform:uppercase}
.time-tools select{width:auto;min-height:40px;font-size:13px;padding:6px 10px}
.clock{display:flex;flex-direction:column;align-items:flex-end;min-width:96px}.clock small{font:9px var(--mono);letter-spacing:.1em;color:var(--muted)}.clock output{font-size:17px;color:var(--fg)}
.tabs{padding:4px;border:1px solid var(--line);border-radius:11px;background:var(--bg);display:flex;gap:4px}
.tabs button{border:0;background:transparent;min-height:38px;font-size:12px;padding:6px 14px}
.tabs button[aria-pressed=true]{background:var(--app-accent);color:#241204}
.tabs button[aria-pressed=false]{color:var(--muted)}

.meter-strip{display:grid;grid-template-columns:repeat(6,minmax(0,1fr));border-bottom:1px solid var(--line);background:var(--bg)}
.readout{padding:12px 18px 13px;border-right:1px solid var(--line);min-width:0;position:relative}.readout:last-child{border-right:0}
.readout span{display:block;font:9px var(--mono);letter-spacing:.1em;color:var(--muted)}
.readout strong{display:block;font:500 22px/1.35 var(--mono);margin-top:3px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.readout strong small{font:11px var(--mono);color:var(--muted)}
.readout em{display:block;font-style:normal;font-size:11px;color:var(--muted);line-height:1.4;margin-top:1px}
.readout[data-tone]:before{content:'';position:absolute;top:15px;right:14px;width:7px;height:7px;border-radius:50%;background:var(--good);box-shadow:0 0 10px currentColor;color:var(--good)}
.readout[data-tone=warn]:before{background:var(--warn);color:var(--warn)}.readout[data-tone=bad]:before{background:var(--bad);color:var(--bad)}
.readout[data-tone=bad] strong{color:var(--bad)}

.visual-switch{display:none!important}
.bench-toolbar{grid-area:tool}.meter-strip{grid-area:read}.now-bar{grid-area:now}
.stage{grid-area:stage;display:grid;grid-template-columns:minmax(0,1.04fr) minmax(0,1fr);border-bottom:1px solid var(--line);background:var(--panel)}
.panel{padding:14px 16px 14px;min-width:0}
.map-panel{border-right:1px solid var(--line)}
.panel-head{display:flex;justify-content:space-between;align-items:flex-start;gap:8px 12px;margin-bottom:10px;flex-wrap:wrap}
.panel-head h2{font:620 21px/1.1 var(--display);letter-spacing:-.03em}
.panel-head .eyebrow{margin-bottom:5px}
.legend{display:flex;gap:12px;flex-wrap:wrap;font-size:11px;color:var(--muted);padding-top:4px}
.legend i{display:inline-block;width:14px;height:9px;border-radius:2px;margin-right:6px;vertical-align:middle;font-style:normal;background:none}
.legend .k-data{background:var(--data)}.legend .k-ack{background:var(--ack);border-radius:5px}
.legend .k-ack.dashed{height:0;border-top:2px dashed var(--ack);background:none;border-radius:0}
.legend .k-lost{width:auto;height:auto;color:var(--bad);font:700 12px var(--mono);margin-right:4px}
.legend .k-route{height:3px;background:var(--app-accent)}
.legend .k-timer{width:7px;height:12px;border:2px solid var(--muted);border-right:0;border-radius:0;background:none}
.legend .k-idle{background:color-mix(in srgb,var(--bad) 22%,transparent);border:1px solid color-mix(in srgb,var(--bad) 45%,transparent)}
.panel-note{font-size:11.5px;color:var(--muted);margin-top:10px;line-height:1.6}.panel-note b{color:var(--fg)}

/* network map */
.map-wrap{background:var(--stage);border:1px solid var(--stage-line);border-radius:12px;overflow:hidden}
.map{display:block;width:100%;height:auto;aspect-ratio:640/340}
.map.compact{aspect-ratio:460/330}
.map.compact .m-name,.map.compact .m-rname{font-size:16px}.map.compact .m-delay text{font-size:14px}.map.compact .m-timer-text,.map.compact .m-tally,.map.compact .m-lost text{font-size:14px}.map.compact .m-pkt.data text{font-size:13px}.map.compact .m-off{font-size:11.5px}
.map text{font-family:var(--mono);text-anchor:middle}
.m-link{stroke:var(--stage-line);stroke-width:3;stroke-linecap:round}
:root[data-theme=light] .m-link:not(.on):not(.down){stroke:#d6cfc4}
.m-link.on{stroke:var(--app-accent);stroke-width:4.5;opacity:.85}
.m-link.down{stroke:var(--bad);stroke-dasharray:4 7;opacity:.5}
.m-delay rect{fill:var(--panel);stroke:var(--line)}.m-delay text{font-size:10.5px;fill:var(--muted)}
.m-delay.on rect{stroke:color-mix(in srgb,var(--app-accent) 60%,var(--line))}.m-delay.on text{fill:var(--accent-text);font-weight:500}
.m-delay.down text{fill:var(--bad)}
.m-node rect,.m-node circle:not(.m-timer-track){fill:var(--node);stroke:var(--node-edge);stroke-width:1.6}
.m-end .m-screen{fill:color-mix(in srgb,var(--ack) 16%,var(--stage));stroke:none}
.m-end .m-base{stroke:var(--node-edge);stroke-width:3;stroke-linecap:round}
.m-timer-track{fill:none;stroke:var(--stage-line);stroke-width:3}
.m-name{font-size:12px;fill:var(--fg);font-weight:500}
.m-router.on circle{stroke:var(--app-accent)}
.m-rname{font-size:12.5px;fill:var(--fg);font-weight:500}
.m-node.off{opacity:.55}.m-node.off circle,.m-node.off rect{stroke:var(--bad);stroke-dasharray:4 3}
.m-off{font-size:9.5px;fill:var(--bad);letter-spacing:.1em}
.m-click{cursor:pointer}.m-click:hover circle,.m-click:hover rect:first-of-type{stroke:var(--app-accent);stroke-width:2.4}
.m-click:focus{outline:none}.m-click:focus-visible circle:not(.m-timer-track),.m-click:focus-visible>rect:first-of-type{stroke:var(--app-accent);stroke-width:3}
.m-timer{fill:none;stroke:var(--app-accent);stroke-width:3.5;stroke-linecap:round}.m-timer.warn{stroke:var(--bad)}
.m-timer-text{font-size:10.5px;fill:var(--accent-text)}.m-timer-text.warn{fill:var(--bad)}
.m-flash{fill:none;stroke:var(--bad);stroke-width:5;opacity:.7}
.m-tally{font-size:10.5px;fill:var(--muted)}
.m-pkt rect{stroke:color-mix(in srgb,#000 25%,transparent);stroke-width:1}
.m-pkt.data rect{fill:var(--data)}.m-pkt.data text{fill:var(--data-ink);font-size:11.5px;font-weight:500}
.m-pkt.ack rect{fill:var(--ack)}.m-pkt.ack text{fill:var(--ack-ink);font-size:10px;font-weight:500}
.m-pkt .retry{fill:var(--panel);stroke:var(--data);stroke-width:1.5}.m-pkt .retry-n{fill:var(--accent-text);font-size:9px}
.m-lost circle{fill:color-mix(in srgb,var(--bad) 18%,var(--stage));stroke:var(--bad);stroke-width:1.5}
.m-lost path{stroke:var(--bad);stroke-width:2.6;stroke-linecap:round}.m-lost text{font-size:10px;fill:var(--bad)}

/* message cells */
.queues{grid-area:queues;display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:10px;padding:12px 16px 14px;align-content:start}
.queues .log{grid-column:1/-1;margin-top:0}
.queue{border:1px solid var(--line);border-radius:11px;background:var(--bg);padding:9px 11px 10px;min-width:0}
.queue-head{display:flex;justify-content:space-between;gap:10px;font:9px var(--mono);letter-spacing:.1em;color:var(--muted);margin-bottom:7px}
.queue-head em{font-style:normal;letter-spacing:.02em;color:var(--fg);text-align:right}
.cells{list-style:none;margin:0;padding:0;display:flex;flex-wrap:wrap;gap:4px}
.cell{position:relative;display:flex;flex-direction:column;align-items:center;min-width:34px;flex:1 1 34px;max-width:96px;padding:3px 4px 4px;border:1px solid var(--line);border-radius:7px;background:var(--panel);transition:background .2s,border-color .2s}
.cell b{font:9px var(--mono);color:var(--soft);font-weight:400}
.cell span{font:500 12px/1.3 var(--mono);white-space:nowrap;overflow:hidden;max-width:100%;text-overflow:clip}
.cell i{position:absolute;top:-7px;right:-5px;font:500 9px/1 var(--mono);font-style:normal;color:var(--accent-text);background:var(--panel);border-radius:6px;padding:1px 3px}
.cell i:empty{display:none}
#senderCells .cell[data-state=queued] span{color:var(--muted)}
#senderCells .cell[data-state=sending]{border-color:var(--data);background:color-mix(in srgb,var(--data) 14%,var(--panel))}
#senderCells .cell[data-state=acked]{border-color:color-mix(in srgb,var(--ack) 55%,var(--line));background:color-mix(in srgb,var(--ack) 12%,var(--panel))}
#senderCells .cell[data-state=acked] b:after{content:' ✓';color:var(--ack)}
#senderCells .cell[data-state=failed]{border-color:var(--bad);background:color-mix(in srgb,var(--bad) 12%,var(--panel))}
#receiverCells .cell[data-state=empty]{border-style:dashed;background:transparent}#receiverCells .cell[data-state=empty] span{visibility:hidden}
#receiverCells .cell[data-state=stored],#receiverCells .cell[data-state=dup]{border-color:color-mix(in srgb,var(--good) 55%,var(--line));background:color-mix(in srgb,var(--good) 12%,var(--panel))}
#receiverCells .cell i{color:var(--bad)}

/* timing diagram */
.seq-head{position:relative;height:22px;background:var(--stage);border:1px solid var(--stage-line);border-bottom:0;border-radius:12px 12px 0 0}
.seq-head span{position:absolute;top:4px;transform:translateX(-50%);font:500 10.5px var(--mono);color:var(--muted);white-space:nowrap}
.seq-head span.end{color:var(--fg)}
.seq-scroll{height:clamp(300px,24vw,340px);overflow-y:auto;overflow-x:hidden;background:var(--stage);border:1px solid var(--stage-line);border-top:0;border-radius:0 0 12px 12px;overscroll-behavior:contain}
.seq-scroll:focus-visible{outline-offset:-2px}
.seq{display:block}
.seq text{font-family:var(--mono)}
.s-grid{stroke:var(--stage-line);stroke-width:1}
.s-tick{font-size:9.5px;fill:var(--soft)}
.s-life{stroke:var(--node-edge);stroke-width:1.2;stroke-dasharray:2 4}.s-life.end{stroke:var(--muted);stroke-width:2;stroke-dasharray:none;opacity:.6}
.s-hop{stroke-width:2;stroke-linecap:round}
.s-hop.data{stroke:var(--data)}.s-hop.ack{stroke:var(--ack);stroke-dasharray:5 4;stroke-width:1.7}
.s-hop.lost{opacity:.8}
.s-arr.data{fill:var(--data)}.s-arr.ack{fill:var(--ack)}
.s-label{font-size:10px}.s-label.data{fill:var(--accent-text)}.s-label.ack{fill:var(--ack)}
.s-x path{stroke:var(--bad);stroke-width:2.6;stroke-linecap:round}
.s-dot{fill:var(--good)}.s-dot.ack{fill:var(--ack)}.s-dot.dup{fill:var(--stage);stroke:var(--bad);stroke-width:1.6}
.s-dup{font-size:9.5px;fill:var(--bad);text-anchor:end}
.s-timer{fill:none;stroke:var(--muted);stroke-width:2;opacity:.55}.s-timer.live{stroke:var(--app-accent);opacity:1}.s-timer.fired{stroke:var(--bad);opacity:1}
.s-timeout{font-size:10px;fill:var(--bad)}
.s-stall{fill:color-mix(in srgb,var(--bad) 11%,transparent);stroke:color-mix(in srgb,var(--bad) 30%,transparent);stroke-width:1;stroke-dasharray:3 3}
.s-stall-text{font-size:10.5px;fill:var(--bad);text-anchor:middle;letter-spacing:.04em}
.s-now{stroke:var(--fg);stroke-width:1;stroke-dasharray:6 4;opacity:.65}
.s-now-text{font-size:9.5px;fill:var(--fg);text-anchor:end;opacity:.8}
.s-empty{font-size:13px;fill:var(--bad);text-anchor:middle}
.log{margin-top:8px;font-size:12px}
.log summary{cursor:pointer;color:var(--accent-text);min-height:32px;display:inline-flex;align-items:center;font-weight:600}
.log-list{margin:6px 0 0;padding:0 0 0 0;list-style:none;max-height:180px;overflow:auto;font:11px/1.6 var(--mono);color:var(--muted)}
.log-list time{color:var(--soft);margin-right:6px}

.now-bar{display:flex;align-items:center;gap:12px;padding:12px 18px;border-bottom:1px solid var(--line);background:var(--bg);min-height:50px}
.now-bar p{font-size:14px;line-height:1.5}
.now-dot{width:10px;height:10px;flex:0 0 10px;border-radius:50%;background:var(--soft)}
.now-dot.live{background:var(--app-accent);box-shadow:0 0 0 4px color-mix(in srgb,var(--app-accent) 25%,transparent)}
.now-dot.good{background:var(--good)}.now-dot.bad{background:var(--bad);box-shadow:0 0 0 4px color-mix(in srgb,var(--bad) 22%,transparent)}

/* controls */
.side{grid-area:side;border-left:1px solid var(--line);background:var(--panel);padding:12px 16px 16px;display:grid;gap:12px;align-content:start;min-width:0}
.group{border:0;margin:0;padding:0;min-width:0;display:grid;gap:9px;align-content:start}
.group+.group{border-top:1px solid var(--line);padding-top:12px}
.side .hint{margin-top:1px;font-size:11px}.side input[type=range]{min-height:30px}
.more{border:1px solid var(--line);border-radius:10px;padding:0 12px}
.more summary{cursor:pointer;min-height:40px;display:flex;align-items:center;font-size:12.5px;font-weight:600;list-style:none}.more summary::-webkit-details-marker{display:none}
.more summary:after{content:'+';margin-left:auto;font:16px var(--mono);color:var(--accent-text)}.more[open] summary:after{content:'−'}
.more-body{display:grid;gap:12px;padding-bottom:12px}
.group legend{float:left;width:100%;font:10px var(--mono);letter-spacing:.11em;text-transform:uppercase;color:var(--muted);padding:0;margin-bottom:2px}
.group legend span{color:var(--accent-text);margin-right:6px}
.control{min-width:0}
.control-head{display:flex;justify-content:space-between;align-items:baseline;gap:10px}
.control-head label{color:var(--fg);font-size:13px;font-weight:600}
.control select,.control input[type=text],.control input[type=number]{min-height:40px;font-size:15px;margin-top:4px;padding:7px 10px}
.control input[type=text]{font-family:var(--mono);letter-spacing:.04em}
.seed-row{display:flex;gap:8px;align-items:center}.seed-row input{flex:1;min-width:0}.seed-row button{min-height:40px;margin-top:4px;font-size:12px;white-space:nowrap}
.scale{display:flex;justify-content:space-between;font:9px var(--mono);color:var(--soft);margin-top:-2px;gap:8px}
.hint{font-size:11.5px;color:var(--muted);margin-top:5px;line-height:1.5}.hint.warn{color:var(--bad)}
.odds{border:1px dashed var(--line);border-radius:10px;padding:11px 13px}
.odds span{display:block;font:9px var(--mono);letter-spacing:.08em;color:var(--accent-text);margin-bottom:5px}
.odds p{font-size:12px;color:var(--muted);line-height:1.6}.odds b{color:var(--fg);font-weight:600}

/* learn */
.learn{display:grid;grid-template-columns:1.15fr 1fr;gap:16px;margin-top:18px}
.learn-panel{background:var(--panel);border:1px solid var(--line);border-radius:14px;padding:20px 22px;min-width:0}
.learn-panel h2{font:620 26px/1.1 var(--display);letter-spacing:-.03em;margin-bottom:12px}
.happening p{font-size:14px;line-height:1.7;color:var(--muted);padding:9px 0;border-top:1px solid var(--line);display:grid;grid-template-columns:96px minmax(0,1fr);gap:12px}
.happening p:first-child{border-top:0}
.happening p .k{font:9px/2.3 var(--mono);letter-spacing:.1em;text-transform:uppercase;color:var(--accent-text)}
.happening b{color:var(--fg);font-weight:600}
.predict{margin-top:14px;border:1px dashed var(--line);border-radius:12px;padding:14px 16px;background:var(--bg)}
.predict h3{font-size:15px;line-height:1.45;margin-bottom:10px}
.predict-choices{display:flex;gap:8px;flex-wrap:wrap}.predict-choices button{min-height:40px;font-size:13px;padding:6px 16px}
.predict-choices button.right{border-color:var(--good);background:color-mix(in srgb,var(--good) 14%,var(--panel))}
.predict-choices button.wrong{border-color:var(--bad);background:color-mix(in srgb,var(--bad) 12%,var(--panel))}
.predict-result{font-size:13px;color:var(--muted);line-height:1.6;margin-top:10px}.predict-result:empty{display:none}
.predict-result .link-button{display:inline;min-height:0;margin-left:4px}
.challenges{list-style:none;margin:0 0 8px;padding:0;display:grid;gap:10px}
.challenges li{border:1px solid var(--line);border-radius:11px;padding:12px 14px;background:var(--bg);transition:border-color .2s}
.challenges li.now{border-color:var(--good)}
.ch-head{display:flex;align-items:center;gap:10px}
.ch-mark{width:18px;height:18px;flex:0 0 18px;border-radius:50%;border:1.5px solid var(--soft);display:grid;place-items:center}
.done .ch-mark{background:var(--good);border-color:var(--good)}
.done .ch-mark:after{content:'';width:8px;height:4px;border:2px solid var(--bg);border-top:0;border-right:0;transform:rotate(-45deg) translate(1px,-1px)}
.challenges strong{font-size:14px}
.challenges p{font-size:12.5px;color:var(--muted);margin:5px 0 0 28px;line-height:1.55}
.challenges .ch-progress{font:11px var(--mono);color:var(--soft)}.now .ch-progress{color:var(--good)}
.challenges details{margin:6px 0 0 28px}.challenges summary{font-size:12px;cursor:pointer;color:var(--accent-text);min-height:28px;display:inline-flex;align-items:center}
.challenges details p{margin-left:0}

/* notes */
.notes{margin-top:16px;display:grid;gap:8px}
.notes details{background:var(--panel);border:1px solid var(--line);border-radius:12px;padding:0 20px}
.notes summary{cursor:pointer;min-height:52px;display:flex;align-items:center;font-weight:600;font-size:14px;list-style:none}
.notes summary::-webkit-details-marker{display:none}
.notes summary:after{content:'+';margin-left:auto;font:18px var(--mono);color:var(--accent-text)}
.notes details[open] summary:after{content:'−'}
.notes-body{padding:0 0 18px;max-width:900px}
.notes-body p,.notes-body li{font-size:13.5px;color:var(--muted);line-height:1.75;margin-bottom:10px}
.notes-body ul{padding-left:18px;margin:0}
.notes-body code{font:12.5px var(--mono);color:var(--accent-text)}
.notes-body b{color:var(--fg)}
.notes-body a{color:var(--fg)}
.noscript{padding:20px;color:var(--muted)}
.app-footer{margin-top:26px}

@media(max-width:1280px){
  .question-grid{grid-template-columns:repeat(3,minmax(0,1fr))}
  .meter-strip{grid-template-columns:repeat(3,minmax(0,1fr))}
  .readout:nth-child(3){border-right:0}.readout:nth-child(-n+3){border-bottom:1px solid var(--line)}
}
@media(max-width:1099px){
  .bench{grid-template-columns:minmax(0,1fr);grid-template-areas:'tool' 'read' 'stage' 'now' 'side' 'queues';grid-template-rows:none}
  .side{border-left:0;border-bottom:1px solid var(--line);grid-template-columns:minmax(0,1fr) minmax(0,1fr);column-gap:24px;padding:14px 18px}
  .group+.group{border-top:0;padding-top:0}
  .seq-scroll{height:360px}
}
@media(max-width:1020px){
  .stage{grid-template-columns:minmax(0,1fr)}
  .map-panel{border-right:0;border-bottom:1px solid var(--line)}
  .learn{grid-template-columns:minmax(0,1fr)}
}
@media(max-width:760px){
  .app-header{padding-inline:16px;min-height:62px}
  .app-header strong{font-size:11px}.app-header strong span{display:none}
  .app-main{padding:26px 14px 24px}
  .intro{flex-direction:column;align-items:flex-start;gap:16px;padding-bottom:22px}
  .intro-glyph{width:84px;height:56px;flex-basis:84px}
  .intro-note{gap:14px}.intro-note p{font-size:13px}
  .question-grid{grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:8px}
  .question-grid button{padding:12px}.question-grid strong{font-size:13.5px}
  .section-label span:last-child{display:none}
  .bench-toolbar{padding:10px 12px}
  .transport{width:100%;display:grid;grid-template-columns:1fr 1fr}.transport button{padding-inline:8px}
  .time-tools{width:100%;justify-content:space-between}
  .meter-strip{grid-template-columns:repeat(2,minmax(0,1fr))}
  .readout{padding:10px 13px;border-bottom:1px solid var(--line)}
  .readout:nth-child(3){border-right:1px solid var(--line)}
  .readout:nth-child(2n){border-right:0}.readout:nth-child(n+5){border-bottom:0}
  .readout strong{font-size:18px}
  .panel{padding:14px 12px 14px}
  .panel-head{margin-bottom:10px}.panel-head h2{font-size:21px}
  .panel-head .legend{gap:9px;font-size:10px}
  .visual-switch{display:flex!important}.visual-switch button{flex:1}
  .bench{grid-template-areas:'tool' 'stage' 'now' 'side' 'queues' 'read'}
  .stage{position:sticky;top:0;z-index:5;box-shadow:0 8px 18px #0000002e}
  .stage[data-view=map] .timing-panel,.stage[data-view=timing] .map-panel{display:none}
  .map-panel{border-bottom:0}
  .stage .panel{padding:8px 12px 10px}.stage .panel-head{margin-bottom:6px}.stage .panel-head h2,.stage .panel-note{display:none}
  .stage .visual-switch{margin:8px 12px 0}.stage .visual-switch button{min-height:34px}
  .side{grid-template-columns:minmax(0,1fr);padding:14px}
  .group+.group{border-top:1px solid var(--line);padding-top:12px}
  .queues{grid-template-columns:minmax(0,1fr);padding:12px}
  .meter-strip{border-top:1px solid var(--line)}
  .seq-scroll{height:min(260px,34svh)}
  .cells{display:grid;grid-template-columns:repeat(auto-fit,minmax(38px,1fr))}.cell{min-width:0;max-width:none;padding-inline:2px}.cell span{font-size:11px}
  .now-bar{padding:11px 14px}.now-bar p{font-size:13px}
  .learn-panel{padding:17px 15px}
  .happening p{grid-template-columns:minmax(0,1fr);gap:2px;font-size:13.5px}
  .challenges p,.challenges details{margin-left:0}
  .notes details{padding:0 15px}
}
@media(max-width:420px){
  .question-grid small{display:none}.question-grid strong{font-size:13px}.question-grid span{margin-bottom:6px}
  .speed-label{display:none}
}
@media(prefers-reduced-motion:reduce){.cell{transition:none}}