@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;--target:#62d9ef;--arm:#ff8a1f;--ghost:#9fb3c4;--stage:#0a1117;--stage-line:#1d2a35;--grid:#1a2630;--grid-strong:#2c3a46;
  --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;--target:#0a84a0;--arm:#e56f00;--ghost:#6d7e8f;--stage:#f8f6f2;--stage-line:#e4ded5;--grid:#ebe6de;--grid-strong:#d3cbc0}

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{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}
:root[data-theme=light] .eyebrow,:root[data-theme=light] output{color:var(--accent-text)}

/* 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-header a:before{color:var(--app-accent)}
.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:480px}.intro-note p{color:var(--muted);font-size:14px;line-height:1.7}
.intro-glyph{width:92px;height:92px;flex:0 0 92px;fill:none;stroke-linecap:round;stroke-linejoin:round}
.intro-glyph .g-arm{stroke:var(--accent-text);stroke-width:7}.intro-glyph .g-ghost{stroke:var(--ghost);stroke-width:4;stroke-dasharray:5 6;opacity:.8}
.intro-glyph .g-floor{stroke:var(--soft);stroke-width:2}.intro-glyph .g-joint{fill:var(--bg);stroke:var(--fg);stroke-width:3}.intro-glyph .g-target{fill:none;stroke:var(--target);stroke-width:3.5}

/* 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{border:1px solid var(--line);border-radius:17px;overflow:hidden;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}
.bench-status{display:flex;align-items:center;gap:10px;font:500 12.5px var(--mono);letter-spacing:.02em;color:var(--fg);min-height:42px}
.bench-status i{width:9px;height:9px;border-radius:50%;background:var(--good);box-shadow:0 0 10px var(--good);flex:0 0 9px}
.bench-status[data-tone=warn] i{background:var(--warn);box-shadow:0 0 10px var(--warn)}.bench-status[data-tone=bad] i{background:var(--bad);box-shadow:0 0 10px var(--bad)}
.bench-status[data-tone=bad]{color:var(--bad)}
.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)}
.bench-actions{display:flex;gap:8px;flex-wrap:wrap}.bench-actions button{min-height:42px;font-size:12px}

.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}
.visuals{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);border-bottom:1px solid var(--line)}
.panel{padding:16px 18px 18px;min-width:0}
.arm-panel{border-right:1px solid var(--line);display:flex;flex-direction:column}
.panel-head{display:flex;justify-content:space-between;align-items:flex-start;gap:12px;margin-bottom:12px;flex-wrap:wrap}
.panel-head h2{font:620 24px/1.1 var(--display);letter-spacing:-.03em}
.legend{display:flex;gap:14px;flex-wrap:wrap;font-size:11px;color:var(--muted);padding-top:4px}
.legend i{display:inline-block;width:14px;height:4px;border-radius:2px;margin-right:6px;vertical-align:middle;background:var(--arm)}
.legend i.lg-target{width:9px;height:9px;border-radius:50%;background:transparent;border:2px solid var(--target)}
.legend i.lg-ghost{background:repeating-linear-gradient(90deg,var(--ghost) 0 4px,transparent 4px 7px)}
.legend i.lg-zone{height:9px;background:color-mix(in srgb,var(--good) 22%,transparent);border:1px solid color-mix(in srgb,var(--good) 60%,transparent)}
.legend i.lg-blocked{height:9px;background:repeating-linear-gradient(135deg,color-mix(in srgb,var(--warn) 55%,transparent) 0 2px,transparent 2px 5px);border:1px solid color-mix(in srgb,var(--warn) 50%,transparent)}
.legend i.lg-floor{height:9px;background:repeating-linear-gradient(45deg,color-mix(in srgb,var(--soft) 75%,transparent) 0 1.5px,color-mix(in srgb,var(--soft) 18%,transparent) 1.5px 5px);border:1px solid color-mix(in srgb,var(--soft) 60%,transparent)}
.legend i.lg-body{height:9px;border-radius:5px;background:color-mix(in srgb,var(--arm) 22%,transparent)}
.legend i.lg-ob{width:9px;height:9px;border-radius:50%;background:color-mix(in srgb,var(--bad) 55%,transparent)}
.legend i.lg-sol{width:9px;height:9px;border-radius:50%;background:var(--target)}
.legend i.lg-now{width:9px;height:9px;border-radius:50%;background:var(--arm);box-shadow:0 0 0 2px var(--panel),0 0 0 3px var(--fg)}
.legend i.lg-trail{height:2px;background:var(--fg)}
.dg-legend{margin-top:10px;padding-top:0;gap:6px 14px}
.panel-note{font-size:11.5px;color:var(--muted);margin-top:8px;line-height:1.6}

/* 3D stage */
.stage3d{position:relative;flex:1;min-height:clamp(400px,38vw,560px);border-radius:12px;overflow:hidden;border:1px solid var(--stage-line);
  background:radial-gradient(ellipse at 50% 30%,#26313c 0%,#141b22 55%,#0b1015 100%);touch-action:none}
:root[data-theme=light] .stage3d{background:radial-gradient(ellipse at 50% 30%,#ffffff 0%,#ece8e1 60%,#ddd7ce 100%)}
.stage3d.failed{min-height:0;flex:0 0 auto;background:var(--stage)}
.a3-host{position:absolute;inset:0}
.a3-canvas{display:block;outline:none;cursor:grab}.a3-canvas:active{cursor:grabbing}.a3-canvas.over-target{cursor:pointer}.a3-canvas.dragging{cursor:move}
.a3-canvas:focus-visible{outline:2px solid var(--app-accent);outline-offset:-3px}
.a3-labels{position:absolute;inset:0;pointer-events:none;overflow:hidden}
.a3-label{position:absolute;left:0;top:0;padding:3px 8px;font:500 10.5px var(--mono);letter-spacing:.03em;border-radius:20px;white-space:nowrap;
  background:color-mix(in srgb,var(--panel) 84%,transparent);border:1px solid var(--line);color:var(--fg);backdrop-filter:blur(4px);box-shadow:0 2px 10px #0004}
.a3-label-elbow{border-color:color-mix(in srgb,var(--arm) 60%,var(--line))}
.a3-label-target{border-color:color-mix(in srgb,var(--target) 60%,var(--line));color:var(--target)}
.a3-status{position:absolute;left:12px;top:12px;font:500 11px var(--mono);letter-spacing:.04em;padding:6px 11px;border-radius:20px;background:color-mix(in srgb,var(--panel) 85%,transparent);border:1px solid var(--app-accent);color:var(--accent-text);opacity:0;transition:opacity .2s;pointer-events:none;max-width:calc(100% - 24px)}
.a3-status.on{opacity:1}
.a3-hint{position:absolute;right:12px;bottom:10px;font:10px var(--mono);color:var(--muted);pointer-events:none}
.a3-fallback{padding:16px;color:var(--muted);font-size:13px;line-height:1.6}
.stage-tools{display:flex;align-items:center;justify-content:space-between;gap:10px;flex-wrap:wrap;margin-top:10px}
.tool-buttons{display:flex;gap:6px;flex-wrap:wrap}.tool-buttons button{min-height:36px;font-size:11.5px;padding:6px 11px}

/* diagrams */
.diagram-tabs{display:inline-flex}
.diagram-wrap{background:var(--stage);border:1px solid var(--stage-line);border-radius:12px;overflow:hidden}
.diagram{display:block;width:100%;height:auto;aspect-ratio:760/450;touch-action:none;user-select:none;-webkit-user-select:none;cursor:crosshair}
.diagram.jm{cursor:default}
.diagram text{font-family:var(--mono)}
.sv-grid{stroke:var(--grid);stroke-width:1}.sv-axis{stroke:var(--grid-strong);stroke-dasharray:3 4}
.sv-tick{fill:var(--soft)}.sv-title{fill:var(--muted);letter-spacing:.08em}.sv-note{fill:var(--soft);font-style:italic}
.sv-warn{fill:var(--bad);letter-spacing:.06em}
.sv-zone{fill:color-mix(in srgb,var(--good) 13%,transparent)}
.sv-zone-edge{fill:none;stroke:color-mix(in srgb,var(--good) 70%,transparent);stroke-width:1.4;stroke-dasharray:6 4}
.sv-zone-label{fill:var(--good)}
.sv-blocked{fill:color-mix(in srgb,var(--warn) 22%,transparent)}
.sv-ground{fill:color-mix(in srgb,var(--soft) 22%,var(--stage))}.sv-ground-hatch{stroke:color-mix(in srgb,var(--soft) 45%,transparent);stroke-width:1.2}
.sv-floor-line{stroke:var(--fg);stroke-width:2;opacity:.75}
.sv-floor-note{fill:var(--fg);font-weight:500;paint-order:stroke;stroke:color-mix(in srgb,var(--soft) 22%,var(--stage));stroke-width:4px;stroke-linejoin:round}
.sv-floorblock{fill:color-mix(in srgb,var(--soft) 16%,transparent)}.sv-hatch{stroke:color-mix(in srgb,var(--soft) 70%,transparent);stroke-width:1.3}
.sv-body{stroke:var(--arm);stroke-linecap:round;opacity:.13}
.sv-in-ground{paint-order:stroke;stroke:color-mix(in srgb,var(--soft) 22%,var(--stage));stroke-width:4px;stroke-linejoin:round}
.sv-angle,.sv-zone-label,.sv-dist,.sv-gap-label,.sv-ghost-label,.sv-ob-label,.sv-warn,.jm-sol-label,.jm-row-label,.jm-limit-label,.jm-none{paint-order:stroke;stroke:var(--stage);stroke-width:3.5px;stroke-linejoin:round}
.sv-ghost.floor{stroke:var(--bad);opacity:.8}.sv-ghost-joint.floor{stroke:var(--bad)}.sv-ghost-label.floor{fill:var(--bad)}
.jm-floor{fill:color-mix(in srgb,var(--soft) 26%,transparent)}
.sv-pedestal{fill:color-mix(in srgb,var(--soft) 30%,var(--stage));stroke:var(--soft);stroke-width:1}
.sv-ob{fill:color-mix(in srgb,var(--bad) 30%,transparent);stroke:var(--bad);stroke-width:1.4}
.sv-ob-zone{fill:color-mix(in srgb,var(--bad) 7%,transparent);stroke:color-mix(in srgb,var(--bad) 70%,transparent);stroke-width:1;stroke-dasharray:3 3}
.sv-ob.hit{fill:color-mix(in srgb,var(--bad) 55%,transparent)}.sv-ob-label{fill:var(--bad)}
.sv-reachline{stroke:var(--target);stroke-width:1.3;stroke-dasharray:5 5;opacity:.85}
.sv-gap{stroke:var(--bad);stroke-width:2.2;stroke-dasharray:7 5}.sv-closest{fill:var(--stage);stroke:var(--bad);stroke-width:2}.sv-gap-label{fill:var(--bad)}
.sv-dist{fill:var(--target)}
.sv-ghost{fill:none;stroke:var(--ghost);stroke-linecap:round;stroke-linejoin:round;stroke-dasharray:2 9;opacity:.85}
.sv-ghost-joint{fill:none;stroke:var(--ghost);stroke-width:1.5}.sv-ghost-label{fill:var(--ghost)}
.sv-arm{fill:none;stroke:var(--arm);stroke-linecap:round;stroke-linejoin:round;opacity:.95}.sv-arm.hit{stroke:var(--bad)}
.sv-joint{fill:var(--stage);stroke:var(--fg);stroke-width:2.2}.sv-tip{fill:var(--fg)}
.sv-ref{stroke:var(--soft);stroke-width:1;stroke-dasharray:3 3}
.sv-arc{fill:none;stroke:var(--fg);stroke-width:1.6}.sv-arc-elbow{stroke:var(--accent-text)}
.sv-angle{fill:var(--fg);font-weight:500}.sv-angle-elbow{fill:var(--accent-text)}
.sv-scale path{stroke:var(--soft);stroke-width:1.2;fill:none}
.dg-handle{cursor:grab;outline:none}.dg-hit{fill:transparent}
.dg-ring{fill:color-mix(in srgb,var(--target) 18%,transparent);stroke:var(--target);stroke-width:2.2}.dg-dot{fill:var(--target)}
.dg-cross{stroke:var(--target);stroke-width:1.6}
.dg-handle.bad .dg-ring{stroke:var(--bad);fill:color-mix(in srgb,var(--bad) 18%,transparent)}.dg-handle.bad .dg-dot{fill:var(--bad)}.dg-handle.bad .dg-cross{stroke:var(--bad)}
.dg-handle:focus-visible .dg-ring{stroke:var(--app-accent);stroke-width:3.5}
.dragging .dg-handle{cursor:grabbing}
/* joint map */
.jm-bg{fill:var(--stage);stroke:var(--grid-strong)}
.jm-grid{stroke:var(--grid);stroke-width:1}.jm-zero{stroke:var(--grid-strong)}
.jm-tick{fill:var(--soft)}.jm-axis{fill:var(--muted);letter-spacing:.1em}.jm-reach{fill:var(--good)}
.jm-contact{fill:color-mix(in srgb,var(--bad) 38%,transparent)}
.jm-blocked{fill:color-mix(in srgb,var(--warn) 16%,transparent)}
.jm-limit{fill:none;stroke:var(--warn);stroke-width:1.4;stroke-dasharray:6 4}.jm-limit-label{fill:var(--warn)}
.jm-row{stroke:var(--target);stroke-width:1.2;stroke-dasharray:6 5;opacity:.8}.jm-row-label{fill:var(--target)}
.jm-sol{fill:none;stroke:var(--target);stroke-width:2.2}.jm-sol.chosen{fill:var(--target)}.jm-sol.blocked{stroke:var(--warn)}.jm-sol.blocked.chosen{fill:var(--warn)}
.jm-sol-label{fill:var(--muted)}.jm-sol-label.chosen{fill:var(--fg);font-weight:500}
.jm-none{fill:var(--bad)}
.jm-rest{fill:var(--soft)}
.jm-trail{fill:none;stroke:var(--fg);stroke-width:1.6;opacity:.75}.jm-trail-hit{fill:var(--bad)}
.jm-now{fill:var(--arm);stroke:var(--fg);stroke-width:2}.jm-now.hit{fill:var(--bad)}

.insets{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin-top:12px}
.inset{display:flex;align-items:center;gap:12px;padding:9px 12px;border:1px solid var(--line);border-radius:11px;background:var(--bg);min-width:0}
.inset span{display:block;font:9px var(--mono);letter-spacing:.1em;color:var(--muted)}
.inset strong{display:block;font:500 16px var(--mono);margin-top:1px;white-space:nowrap}
.inset em{display:block;font-style:normal;font-size:11px;color:var(--muted);line-height:1.4}
.plan{width:84px;height:84px;flex:0 0 84px;touch-action:none;cursor:crosshair}
.pl-axis{stroke:var(--grid-strong);stroke-width:.6}.pl-reach{fill:color-mix(in srgb,var(--good) 12%,transparent);stroke:var(--good);stroke-width:.9;stroke-dasharray:3 2}
.pl-hole{fill:var(--bg);stroke:var(--good);stroke-width:.7}
.pl-ob{fill:color-mix(in srgb,var(--bad) 35%,transparent);stroke:var(--bad);stroke-width:.8}.pl-ob.hit{fill:color-mix(in srgb,var(--bad) 60%,transparent)}
.pl-dir{stroke:var(--target);stroke-width:.8;stroke-dasharray:2 2}.pl-arm{fill:none;stroke:var(--arm);stroke-width:3;stroke-linecap:round;stroke-linejoin:round}
.pl-base{fill:var(--fg)}.pl-label{font:7px var(--mono);fill:var(--soft)}
.plan .dg-ring{stroke-width:1.4}
.stretch-inset{flex-direction:column;align-items:stretch;gap:8px}
.stretch-bar{position:relative;height:12px;border-radius:6px;background:color-mix(in srgb,var(--soft) 14%,transparent);margin-top:2px}
.stretch-bar i{position:absolute;top:0;bottom:0;border-radius:6px}
.sb-hole{left:0;background:repeating-linear-gradient(135deg,color-mix(in srgb,var(--soft) 40%,transparent) 0 2px,transparent 2px 5px)}
.sb-zone{background:linear-gradient(90deg,color-mix(in srgb,var(--good) 25%,transparent),color-mix(in srgb,var(--good) 45%,transparent) 85%,color-mix(in srgb,var(--warn) 70%,transparent))}
.stretch-bar b{position:absolute;top:-4px;width:3px;height:20px;margin-left:-1.5px;border-radius:2px;background:var(--target);box-shadow:0 0 8px var(--target);transition:left .15s}
.stretch-bar b.bad{background:var(--bad);box-shadow:0 0 8px var(--bad)}

/* controls */
.controls{display:grid;grid-template-columns:1fr 1.45fr 1fr;background:var(--panel)}
.group{border:0;margin:0;padding:16px 20px 20px;border-right:1px solid var(--line);min-width:0;display:grid;gap:14px;align-content:start}
.group:last-child{border-right:0}
.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}
.controls .group:nth-child(2){grid-template-columns:1fr 1fr;column-gap:22px}
.controls .group:nth-child(2) legend{grid-column:1/-1}
.control{min-width:0}
.control-head{display:flex;justify-content:space-between;align-items:baseline;gap:10px}
.control-head label,.control-head .label{color:var(--fg);font-size:13px;font-weight:600}
.segmented{display:flex;gap:6px;margin-top:6px}.segmented button{flex:1;min-height:40px;font-size:12.5px;padding:6px 10px}
.hint{font-size:11.5px;color:var(--muted);margin-top:5px;line-height:1.5}
.howto{border:1px dashed var(--line);border-radius:10px;padding:11px 13px}
.howto span{display:block;font:9px var(--mono);letter-spacing:.08em;color:var(--accent-text);margin-bottom:5px}
.howto p{font-size:12px;color:var(--muted);line-height:1.6}

/* 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:84px 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}
.challenges{list-style:none;margin:0;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)}
  .controls{grid-template-columns:1fr 1fr}
  .controls .group:nth-child(2){border-right:0}
  .controls .group:nth-child(3){grid-column:1/-1;border-top:1px solid var(--line);grid-template-columns:1fr 1fr;column-gap:22px}
  .controls .group:nth-child(3) legend{grid-column:1/-1}
  .arm-panel .legend{display:none}
  .diagram-panel .panel-note{display:none}.dg-legend{margin-top:6px;font-size:10.5px;gap:3px 12px}
}
@media(max-width:1020px){
  .visuals{grid-template-columns:minmax(0,1fr)}
  .arm-panel{border-right:0;border-bottom:1px solid var(--line)}
  .stage3d{min-height:440px}
  .learn{grid-template-columns:minmax(0,1fr)}
}
@media(max-width:760px){
  .app-header{padding-inline:16px;min-height:62px}
  .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:56px;height:56px;flex-basis:56px}
  .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}.bench-status{min-height:30px;font-size:12px}
  .bench-actions{width:100%}.bench-actions button{flex:1 1 auto;padding-inline:10px}
  .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}
  .visual-switch{display:flex!important;margin:12px 12px 0}.visual-switch button{flex:1}
  .visuals[data-view=arm] .diagram-panel,.visuals:not([data-view=arm]) .arm-panel{display:none}
  .diagram-tabs{display:none}
  .arm-panel{border-bottom:0}
  .panel{padding:14px 12px}
  .panel-head{margin-bottom:10px}.panel-head h2{font-size:21px}
  .stage3d{min-height:380px}.a3-hint{display:none}
  .diagram{aspect-ratio:760/640}.diagram.jm{aspect-ratio:600/520}
  .dg-legend{font-size:10.5px}
  .insets{grid-template-columns:minmax(0,1fr)}
  .controls,.controls .group:nth-child(2),.controls .group:nth-child(3){grid-template-columns:minmax(0,1fr)}
  .group{border-right:0;border-top:1px solid var(--line);padding:16px 14px 18px}
  .controls .group:first-child{border-top:0}
  .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}
}
@media(prefers-reduced-motion:reduce){.stretch-bar b,.a3-status{transition:none}}

/* ---- stage-centred layout: controls sit beside the stage (≥1100px) ---- */
@media(min-width:1100px){
  .app-main{padding-top:18px}
  .intro{padding-bottom:14px;gap:24px}
  .intro .eyebrow{margin-bottom:6px}
  .intro h1{font-size:clamp(27px,2.2vw,31px);letter-spacing:-.03em}
  .intro-glyph{width:60px;height:60px;flex-basis:60px}
  .intro-note{max-width:560px}.intro-note p{font-size:13px;line-height:1.6}
  .section-label{margin-bottom:7px}
  .question-grid{grid-template-columns:repeat(6,minmax(0,1fr));margin-bottom:12px;gap:8px}
  .question-grid button{padding:8px 12px 9px;min-height:0}
  .question-grid span{margin-bottom:4px}.question-grid strong{font-size:13.5px}.question-grid small{display:none}
  .bench{display:grid;grid-template-columns:minmax(0,1fr) 336px}
  .bench-toolbar,.meter-strip{grid-column:1/-1}
  .bench-toolbar{padding:5px 14px}.bench-actions button{min-height:34px;padding:5px 13px}.bench-status{min-height:32px}
  .meter-strip{grid-template-columns:repeat(6,minmax(0,1fr))}
  .readout{padding:8px 16px 9px;border-bottom:0!important}.readout:nth-child(3){border-right:1px solid var(--line)}
  .readout strong{font-size:18px;line-height:1.25}.readout em{font-size:10.5px}
  .visuals{grid-column:1;border-bottom:0;border-right:1px solid var(--line)}
  .panel{padding:12px 14px 14px}.panel-head{margin-bottom:8px}.panel-head h2{font-size:20px}.panel-head .eyebrow{margin-bottom:4px}
  .stage3d{min-height:330px}
  .arm-panel{position:relative}.stage-tools{position:absolute;left:24px;right:24px;bottom:22px;margin:0;pointer-events:none}.stage-tools .tool-buttons{pointer-events:auto}
  .stage-tools button{background:color-mix(in srgb,var(--panel) 86%,transparent);backdrop-filter:blur(4px);min-height:32px}
  .stage-tools button[aria-pressed=true]{background:color-mix(in srgb,var(--app-accent) 22%,var(--panel))}
  .a3-hint{bottom:auto;top:10px}
  .insets{margin-top:8px}.inset{padding:6px 10px}.plan{width:64px;height:64px;flex-basis:64px}
  .controls{grid-column:2;grid-template-columns:minmax(0,1fr)!important;align-content:start;gap:0;background:var(--bg)}
  .controls .group,.controls .group:nth-child(2),.controls .group:nth-child(3){grid-column:auto;border-right:0;border-top:1px solid var(--line);padding:9px 16px 10px;gap:4px 14px;grid-template-columns:1fr 1fr}
  .controls .group:first-child{border-top:0}
  .controls .group legend{grid-column:1/-1;margin-bottom:0}
  .controls .control{grid-column:span 1}
  .controls .group:first-child .control:last-child,.controls .group:nth-child(3) .control,.controls .group:nth-child(2) .control:nth-of-type(n+3){grid-column:1/-1}
  .controls .hint,.controls .howto{display:none}
  .controls input[type=range]{min-height:26px}
  .control-head label,.control-head .label{font-size:12px}
  .segmented{margin-top:4px}.segmented button{min-height:34px;font-size:11.5px;padding:4px 6px}
  .arm-panel .legend{display:none}
  .diagram-panel .panel-note{display:none}.dg-legend{margin-top:6px;font-size:10.5px;gap:3px 12px}
}
@media(min-width:1100px) and (max-width:1280px){.meter-strip .readout:nth-child(-n+3){border-bottom:0}}
/* phones: keep the view pinned while the controls scroll under it */
@media(max-width:760px){
  .bench{overflow:clip}
  .visuals{position:sticky;top:0;z-index:5;background:var(--panel);box-shadow:0 10px 24px #0005}
  .visuals .panel-head,.visuals .insets,.visuals .panel-note{display:none}
  .visual-switch{margin:8px 10px 0}.visual-switch button{min-height:34px}
  .panel{padding:8px 10px 10px}
  .stage3d{min-height:300px}
  .stage-tools{margin-top:6px}.tool-buttons button{min-height:32px;padding:4px 9px;font-size:11px}
  .dg-legend{margin-top:6px;font-size:10px;gap:4px 10px}
}