/* LearnML marketing site: Nuri's notebook. Tokens match the app (DESIGN.md). */
:root{
  --bg:#F2F4EE; --grid:#E4E8DD; --grid-strong:#D5DBCD; --surface:#FFFFFF; --surface2:#E9EDE3; --ink:#18222C; --muted:#5B6773; --line:#C9D0C1;
  --primary:#18222C; --primary-ink:#FFFFFF; --primary-edge:#000000;
  --hi:#FFC93C; --hi-ink:#3B2A00; --ca:#2A67D6; --cb:#E2721B; --cc:#11928A; --cd:#8752C6; --ce:#C63B6D;
  --page-grid:rgba(24,34,44,.055); --margin-rule:rgba(198,59,109,.42);
  --rings-v:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='38' height='28'%3E%3Ccircle cx='6' cy='18' r='3.8' fill='%23D5DBCD'/%3E%3Ccircle cx='32' cy='18' r='3.8' fill='%23D5DBCD'/%3E%3Cpath d='M6 18C6 5 32 5 32 18' fill='none' stroke='%235B6773' stroke-width='3' stroke-linecap='round'/%3E%3C/svg%3E");
  --rings-h:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='28' height='34'%3E%3Ccircle cx='17' cy='6' r='3.8' fill='%23D5DBCD'/%3E%3Ccircle cx='17' cy='28' r='3.8' fill='%23D5DBCD'/%3E%3Cpath d='M17 6C4 6 4 28 17 28' fill='none' stroke='%235B6773' stroke-width='3' stroke-linecap='round'/%3E%3C/svg%3E");
  --shadow:0 1px 0 rgba(24,34,44,.06), 0 18px 40px -22px rgba(24,34,44,.32);
  --f-display:"Bricolage Grotesque", "Trebuchet MS", system-ui, sans-serif;
  --f-body:"Atkinson Hyperlegible", "Segoe UI", system-ui, sans-serif;
  --f-mono:"JetBrains Mono", ui-monospace, "Cascadia Mono", Consolas, monospace;
  --f-paper:"Literata", Georgia, serif;
  --ease:cubic-bezier(.16,1,.3,1);
  color-scheme:light;
}
@media (prefers-color-scheme: dark){
  :root:not([data-theme="light"]){
    color-scheme:dark;
    --bg:#0F151B; --grid:#161E26; --grid-strong:#243039; --surface:#161F28; --surface2:#1D2833; --ink:#E7EDF2; --muted:#98A5B1; --line:#33414E;
    --primary:#E7EDF2; --primary-ink:#0F151B; --primary-edge:#8C99A5;
    --hi:#F6C63C; --hi-ink:#2C2000; --ca:#5E95F2; --cb:#F39349; --cc:#2FC1B4; --cd:#AA85E6; --ce:#E66793;
    --page-grid:rgba(231,237,242,.05); --margin-rule:rgba(230,103,147,.45);
    --rings-v:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='38' height='28'%3E%3Ccircle cx='6' cy='18' r='3.8' fill='%230F151B'/%3E%3Ccircle cx='32' cy='18' r='3.8' fill='%230F151B'/%3E%3Cpath d='M6 18C6 5 32 5 32 18' fill='none' stroke='%2398A5B1' stroke-width='3' stroke-linecap='round'/%3E%3C/svg%3E");
    --rings-h:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='28' height='34'%3E%3Ccircle cx='17' cy='6' r='3.8' fill='%230F151B'/%3E%3Ccircle cx='17' cy='28' r='3.8' fill='%230F151B'/%3E%3Cpath d='M17 6C4 6 4 28 17 28' fill='none' stroke='%2398A5B1' stroke-width='3' stroke-linecap='round'/%3E%3C/svg%3E");
    --shadow:0 1px 0 rgba(0,0,0,.3), 0 18px 40px -22px rgba(0,0,0,.8);
  }
}
:root[data-theme="dark"]{
  color-scheme:dark;
  --bg:#0F151B; --grid:#161E26; --grid-strong:#243039; --surface:#161F28; --surface2:#1D2833; --ink:#E7EDF2; --muted:#98A5B1; --line:#33414E;
  --primary:#E7EDF2; --primary-ink:#0F151B; --primary-edge:#8C99A5;
  --hi:#F6C63C; --hi-ink:#2C2000; --ca:#5E95F2; --cb:#F39349; --cc:#2FC1B4; --cd:#AA85E6; --ce:#E66793;
  --page-grid:rgba(231,237,242,.05); --margin-rule:rgba(230,103,147,.45);
    --rings-v:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='38' height='28'%3E%3Ccircle cx='6' cy='18' r='3.8' fill='%230F151B'/%3E%3Ccircle cx='32' cy='18' r='3.8' fill='%230F151B'/%3E%3Cpath d='M6 18C6 5 32 5 32 18' fill='none' stroke='%2398A5B1' stroke-width='3' stroke-linecap='round'/%3E%3C/svg%3E");
    --rings-h:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='28' height='34'%3E%3Ccircle cx='17' cy='6' r='3.8' fill='%230F151B'/%3E%3Ccircle cx='17' cy='28' r='3.8' fill='%230F151B'/%3E%3Cpath d='M17 6C4 6 4 28 17 28' fill='none' stroke='%2398A5B1' stroke-width='3' stroke-linecap='round'/%3E%3C/svg%3E");
  --shadow:0 1px 0 rgba(0,0,0,.3), 0 18px 40px -22px rgba(0,0,0,.8);
}

*{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:84px;scrollbar-color:var(--grid-strong) var(--bg)}
body{margin:0;background-color:var(--bg);background-image:linear-gradient(var(--grid) 1px,transparent 1px),linear-gradient(90deg,var(--grid) 1px,transparent 1px);background-size:28px 28px;color:var(--ink);font:17px/1.6 var(--f-body);-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
::selection{background:var(--hi);color:var(--hi-ink)}
:focus-visible{outline:3px solid var(--ca);outline-offset:3px;border-radius:8px}
h1,h2,h3{font-family:var(--f-display);font-weight:800;line-height:1.04;letter-spacing:-.03em;text-wrap:balance;margin:0}
p{margin:0 0 1em;text-wrap:pretty}
a{color:inherit;text-underline-offset:.22em;text-decoration-thickness:2px;text-decoration-color:var(--hi)}
b{font-weight:700}
.mono{font-family:var(--f-mono);font-variant-numeric:tabular-nums;font-weight:600;letter-spacing:-.01em}
.small{font-size:.88rem}
.muted{color:var(--muted)}
.skip{position:absolute;left:12px;top:-60px;z-index:20;background:var(--hi);color:var(--hi-ink);padding:10px 14px;border-radius:10px;font-weight:700;text-decoration:none}
.skip:focus{top:12px}

/* ---------- game-key buttons (the app's .btn) ---------- */
.key{display:inline-flex;align-items:center;justify-content:center;gap:8px;border:0;border-radius:14px;padding:12px 20px;font:700 1rem/1.2 var(--f-body);letter-spacing:.01em;cursor:pointer;text-decoration:none;white-space:nowrap;transition:transform .08s, box-shadow .08s, background-color .15s}
.key:active{transform:translateY(3px)}
.key-ink{background:var(--primary);color:var(--primary-ink);box-shadow:0 4px 0 var(--primary-edge)}
.key-ink:active{box-shadow:0 1px 0 var(--primary-edge)}
.key-hi{background:var(--hi);color:var(--hi-ink);box-shadow:0 4px 0 color-mix(in srgb,var(--hi) 55%,#000)}
.key-hi:hover{background:color-mix(in srgb,var(--hi) 88%,#fff)}
.key-hi:active{box-shadow:0 1px 0 color-mix(in srgb,var(--hi) 55%,#000)}
.key-ghost{background:var(--surface);color:var(--ink);box-shadow:0 3px 0 var(--line), inset 0 0 0 1.5px var(--line)}
.key-ghost:active{box-shadow:0 0 0 var(--line), inset 0 0 0 1.5px var(--line)}
.key.big{font-size:1.12rem;padding:16px 26px;border-radius:16px}
.key.sm{padding:8px 13px;font-size:.9rem;border-radius:11px}
.textlink{font-weight:700;color:var(--ink)}

/* ---------- header ---------- */
.top{position:sticky;top:0;z-index:10;display:flex;align-items:center;gap:24px;max-width:1232px;margin:0 auto;padding:14px 26px;background:var(--bg);border-bottom:1.5px solid transparent;transition:border-color .2s}
.top.scrolled{border-bottom-color:var(--line)}
.mark{display:inline-flex;align-items:center;gap:.36em;font:800 1.5rem/1 var(--f-display);letter-spacing:-.03em;text-decoration:none;color:var(--ink)}
.mark-icon{width:1.25em;height:1.25em;flex:none}
.mark b{background:var(--hi);color:var(--hi-ink);padding:0 .18em;border-radius:.2em;margin-left:1px}
.mark.small{font-size:1.15rem}
.top nav{display:flex;gap:4px;margin-left:auto}
.top nav a{padding:8px 12px;border-radius:10px;font-weight:700;color:var(--muted);text-decoration:none}
.top nav a:hover{color:var(--ink);background:var(--surface2)}

main{padding:10px 26px 40px}

/* ---------- notebook spreads ---------- */
.spread{position:relative;display:grid;grid-template-columns:1.14fr 38px 1fr;max-width:1180px;margin:28px auto 72px;filter:drop-shadow(0 18px 26px rgba(24,34,44,.13))}
.page,.sheet{background-color:var(--surface);background-image:linear-gradient(var(--page-grid) 1px,transparent 1px),linear-gradient(90deg,var(--page-grid) 1px,transparent 1px);background-size:24px 24px}
.page{padding:52px 48px 48px;min-width:0}
.page-left{border-radius:22px 4px 4px 22px;border:1.5px solid var(--line);border-right:0}
.page-right{border-radius:4px 22px 22px 4px;border:1.5px solid var(--line);border-left:0}
.margin{background-image:linear-gradient(90deg,transparent 58px,var(--margin-rule) 58px 60px,transparent 60px),linear-gradient(var(--page-grid) 1px,transparent 1px),linear-gradient(90deg,var(--page-grid) 1px,transparent 1px);background-size:auto,24px 24px,24px 24px;padding-left:92px}
/* the wire binding: drawn rings through punched holes, tiled in whole rings only */
.binding{border-top:1.5px solid var(--line);border-bottom:1.5px solid var(--line);background-color:var(--surface);background-image:var(--rings-v);background-size:38px 28px;background-repeat:no-repeat round;background-position:0 0;padding:6px 0}

.page-left h1{font-size:clamp(2.5rem,4.1vw,3.85rem);margin-bottom:26px}
.marker{background:linear-gradient(transparent 58%,color-mix(in srgb,var(--hi) 80%,transparent) 58% 92%,transparent 92%);padding:0 .06em;margin:0 -.06em;box-decoration-break:clone;-webkit-box-decoration-break:clone}
.page h2{font-size:clamp(2rem,3.3vw,3rem);margin-bottom:22px}
.lede{font-size:1.2rem;max-width:34ch}
.lede.small{font-size:1rem;color:var(--muted)}
.actions{display:flex;flex-wrap:wrap;align-items:center;gap:22px;margin-top:34px}
.note{font-size:.95rem;color:var(--muted);max-width:52ch}
.note b{color:var(--ink)}
.hand{font:700 1.3rem/1.2 var(--f-display);letter-spacing:-.01em;margin-bottom:6px}

/* ---------- the neuron ---------- */
.nstage{position:relative;aspect-ratio:520/300;margin:6px 0 14px}
.nwires{position:absolute;inset:0;width:100%;height:100%;overflow:visible}
.wire{fill:none;stroke:var(--cb);stroke-linecap:round;transition:stroke .25s,stroke-width .25s var(--ease),opacity .25s;stroke-dasharray:420;stroke-dashoffset:0}
.wire.neg{stroke:var(--ca)}
.wire.off{stroke:var(--line);stroke-dasharray:2 9;opacity:1}
.ready .wire.off{animation:none}
.wire.out{stroke:var(--line);stroke-width:4}
.neuron.fire .wire.out{stroke:var(--ink)}
.sum{fill:var(--surface);stroke:var(--ink);stroke-width:2.5;transition:fill .25s}
.neuron.fire .sum{fill:var(--hi)}
.sumt{font:600 26px var(--f-mono);fill:var(--ink)}
.neuron.fire .sumt{fill:var(--hi-ink)}
.nin{position:absolute;left:0;top:var(--y);transform:translateY(-50%);width:23%;min-width:96px;padding:9px 10px;border-radius:12px;border:0;font:700 .9rem/1.15 var(--f-body);cursor:pointer;background:var(--surface);color:var(--muted);box-shadow:0 3px 0 var(--line), inset 0 0 0 1.5px var(--line);transition:background-color .15s,color .15s,transform .08s,box-shadow .08s;text-align:center}
.nin[aria-pressed="true"]{background:var(--ink);color:var(--surface);box-shadow:0 3px 0 var(--primary-edge), inset 0 0 0 1.5px var(--ink)}
.nin:active{transform:translateY(calc(-50% + 2px));box-shadow:0 1px 0 var(--line), inset 0 0 0 1.5px var(--line)}
.nout{position:absolute;left:79%;top:50%;transform:translateY(-50%);display:flex;flex-direction:column;align-items:center;gap:2px;width:21%}
.nout .nuri{width:clamp(56px,7vw,84px);height:auto}
.verdict{font:800 1.05rem/1 var(--f-display);white-space:nowrap}
.weights{display:grid;grid-template-columns:repeat(auto-fit,minmax(250px,1fr));gap:6px 22px;margin-bottom:12px}
.weights label{display:grid;grid-template-columns:7.2em 1fr 2.4em;align-items:center;gap:8px;font-size:.88rem;color:var(--muted)}
.weights output{text-align:right;color:var(--ink);font-size:.92rem}
input[type=range]{-webkit-appearance:none;appearance:none;width:100%;height:26px;background:transparent;cursor:pointer;margin:0}
input[type=range]::-webkit-slider-runnable-track{height:6px;border-radius:99px;background:var(--surface2);box-shadow:inset 0 0 0 1px var(--line)}
input[type=range]::-moz-range-track{height:6px;border-radius:99px;background:var(--surface2);box-shadow:inset 0 0 0 1px var(--line)}
input[type=range]::-webkit-slider-thumb{-webkit-appearance:none;width:18px;height:18px;margin-top:-6px;border-radius:50%;background:var(--ink);border:3px solid var(--surface);box-shadow:0 1px 3px rgba(0,0,0,.3)}
input[type=range]::-moz-range-thumb{width:14px;height:14px;border-radius:50%;background:var(--ink);border:3px solid var(--surface);box-shadow:0 1px 3px rgba(0,0,0,.3)}
.eq{background:var(--surface2);border-radius:12px;padding:10px 14px;font-size:.92rem;line-height:1.7;margin-bottom:14px;font-weight:400}
.eq b{font-weight:600}
.eq .yes{color:var(--cc)}

/* ---------- the digit reader ---------- */
.digit{display:grid;grid-template-columns:minmax(0,300px) 1fr;grid-template-areas:"pad guess" "bars guess";gap:16px 28px;align-items:center;align-content:center;height:100%}
.pad{grid-area:pad;position:relative;aspect-ratio:1;border-radius:18px;background:var(--surface);background-image:linear-gradient(var(--grid) 1px,transparent 1px),linear-gradient(90deg,var(--grid) 1px,transparent 1px);background-size:10% 10%;box-shadow:inset 0 0 0 2px var(--ink)}
.pad canvas{position:absolute;inset:0;width:100%;height:100%;touch-action:none;cursor:crosshair;border-radius:18px}
.padhint{position:absolute;inset:auto 0 18px;text-align:center;font:700 .95rem var(--f-display);color:var(--muted);pointer-events:none;transition:opacity .2s}
.padhint.gone{opacity:0}
.guess{grid-area:guess;text-align:center;display:flex;flex-direction:column;align-items:center}
.guess .nuri{width:64px;height:auto;margin-bottom:6px}
.guess .small{margin:0}
.big-digit{font-size:clamp(5rem,9vw,7.5rem);line-height:1;margin:4px 0 6px;font-weight:600;color:var(--ink)}
.guess.has .big-digit{animation:pop .45s var(--ease)}
@keyframes pop{from{transform:scale(.7);opacity:.3}to{transform:none;opacity:1}}
.guess .key{margin-top:14px}
.barsbox{grid-area:bars;position:relative;justify-self:stretch;width:100%}
.barcap{position:absolute;inset:0 0 auto;margin:0;padding:8px 10px;text-align:center;font:700 .9rem/1.35 var(--f-display);color:var(--muted);border:1.5px dashed var(--line);border-radius:12px;transition:opacity .25s}
.barsbox.live .barcap{opacity:0}
.bars{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:repeat(10,1fr);gap:6px;align-items:end;height:112px;align-content:end}
.bars li{min-width:0;display:flex;flex-direction:column;align-items:center;justify-content:flex-end;height:100%;gap:6px}
.bars i{display:block;width:100%;max-width:30px;height:80px;border-radius:6px 6px 3px 3px;background:var(--line);transform:scaleY(calc(var(--p,0) * .966 + .034));transform-origin:50% 100%;transition:transform .35s var(--ease),background-color .2s}
.bars li.best i{background:var(--hi);box-shadow:inset 0 0 0 1.5px color-mix(in srgb,var(--hi) 60%,#000)}
.bars span{font:600 .85rem var(--f-mono);color:var(--muted)}
.bars li.best span{color:var(--ink)}

/* ---------- single sheets (the road, the lab) ---------- */
.sheet{max-width:1180px;margin:28px auto 72px;border:1.5px solid var(--line);border-radius:22px;padding:52px 56px 46px;box-shadow:var(--shadow)}
.sheet-head{display:grid;grid-template-columns:1.25fr 1fr;gap:20px 56px;align-items:end;margin-bottom:26px}
.sheet-head h2{font-size:clamp(2rem,3.4vw,3.1rem)}
.sheet-head p{margin:0;color:var(--muted);max-width:44ch}
.sheet-foot{margin:26px 0 0}

.road{position:relative;aspect-ratio:1000/560;margin:6px 0 0}
.roadsvg{position:absolute;inset:0;width:100%;height:100%;overflow:visible}
#roadpath{fill:none;stroke:var(--grid-strong);stroke-width:14;stroke-linecap:round;stroke-linejoin:round}
#roadink{fill:none;stroke:var(--ink);stroke-width:3.5;stroke-linecap:round;stroke-linejoin:round;stroke-dasharray:8 12}
.stops{list-style:none;margin:0;padding:0}
.stop{position:absolute;left:var(--x);top:var(--y);transform:translate(-50%,-50%);width:130px;display:flex;flex-direction:column;align-items:center;text-align:center}
.stop button{width:46px;height:46px;border-radius:50%;border:0;background:var(--uc);color:#fff;font:600 1.02rem var(--f-mono);cursor:pointer;box-shadow:0 4px 0 color-mix(in srgb,var(--uc) 55%,#000), 0 0 0 4px var(--surface);transition:transform .15s var(--ease),box-shadow .1s}
.stop button:hover{transform:translateY(-2px) scale(1.06)}
.stop button:active{transform:translateY(2px);box-shadow:0 1px 0 color-mix(in srgb,var(--uc) 55%,#000), 0 0 0 4px var(--surface)}
.stop button[aria-pressed="true"]{box-shadow:0 4px 0 color-mix(in srgb,var(--uc) 55%,#000), 0 0 0 4px var(--surface), 0 0 0 7px var(--uc)}
.stop .lbl{position:absolute;top:100%;margin-top:10px;font:700 .82rem/1.2 var(--f-body);color:var(--ink);background:var(--surface);padding:2px 6px;border-radius:6px}
.stop.below .lbl{top:auto;bottom:100%;margin:0 0 10px}
.stop .lbl small{display:block;font-weight:400;color:var(--muted);font-size:.74rem}

.unitnote{position:relative;max-width:640px;margin:30px auto 0;background:color-mix(in srgb,var(--hi) 30%,var(--surface));border-radius:6px 6px 18px 6px;padding:24px 28px 22px;box-shadow:0 2px 0 rgba(0,0,0,.04),0 14px 26px -18px rgba(24,34,44,.45);transform:rotate(-.6deg)}
.unitnote h3{font-size:1.55rem;margin:0 0 6px;letter-spacing:-.02em}
.unitnote h3 .mono{color:var(--uc,var(--ink));margin-right:6px}
.unitnote > p{margin:0 0 12px}
.unitnote ul{list-style:none;margin:0 0 12px;padding:0;display:flex;flex-wrap:wrap;gap:6px}
.unitnote li{background:var(--surface);border-radius:99px;padding:5px 12px;font-size:.88rem;font-weight:700}
.unitnote .papers{font-size:.9rem;margin:0}
.unitnote .papers i{font-style:normal;font-family:var(--f-paper)}
.unitnote.swap{animation:note .5s var(--ease)}
@keyframes note{from{transform:rotate(-2.2deg) translateY(10px);opacity:.4}to{transform:rotate(-.6deg);opacity:1}}

/* ---------- the paper ---------- */
.margin-notes{list-style:none;padding:0;margin:0 0 22px;display:grid;gap:12px}
.margin-notes li{position:relative;padding-left:30px;max-width:46ch}
.margin-notes li::before{content:"";position:absolute;left:0;top:.25em;width:18px;height:18px;border-radius:5px;border:2px solid var(--ink)}
.margin-notes li::after{content:"";position:absolute;left:3px;top:calc(.25em - 3px);width:20px;height:18px;background:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 20 18'%3E%3Cpath d='M2 9.5 7 14 18 2' fill='none' stroke='%2311928A' stroke-width='3.2' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E") no-repeat}
.paperpage{background:var(--surface);border:1.5px solid var(--line);border-radius:6px;padding:34px 34px 22px;box-shadow:0 22px 32px -26px rgba(24,34,44,.5);transform:rotate(.5deg)}
.pmeta{font:700 .8rem/1.3 var(--f-body);color:var(--muted);margin-bottom:10px;letter-spacing:.01em}
.paperpage h3{font:600 1.5rem/1.2 var(--f-paper);letter-spacing:-.01em;margin-bottom:16px}
.ptext{font:400 1.06rem/1.75 var(--f-paper);margin-bottom:6px}
.hl{font:inherit;color:inherit;border:0;padding:0 .08em;margin:0 -.04em;cursor:pointer;border-radius:3px;background:linear-gradient(transparent 12%,color-mix(in srgb,var(--hi) 55%,transparent) 12% 94%,transparent 94%);transition:background-color .2s}
.hl:hover{background-color:color-mix(in srgb,var(--hi) 30%,transparent)}
.hl[aria-expanded="true"]{background:var(--hi);color:var(--hi-ink)}
.plabel{margin:0 0 14px;font-size:.78rem}
.tutor{display:grid;grid-template-columns:auto 1fr;gap:14px;align-items:start;background:var(--surface2);border-radius:16px;padding:16px 18px;margin:14px 0 10px}
.tutor .nuri{width:56px;height:auto}
.tutor-q{font:700 1rem/1.3 var(--f-display);margin:2px 0 4px}
.tutor-a{margin:0;font-size:.98rem}
.tutor.swap .tutor-a{animation:ink .5s var(--ease)}
@keyframes ink{from{opacity:0;filter:blur(3px)}to{opacity:1;filter:none}}

/* ---------- taped Game Lab frames ---------- */
.taped{list-style:none;margin:8px 0 0;padding:0;display:grid;grid-template-columns:repeat(4,1fr);gap:30px}
.taped li{position:relative;background:var(--surface);border:1.5px solid var(--line);border-radius:6px;padding:10px 10px 16px;transform:rotate(var(--r));box-shadow:0 14px 22px -18px rgba(24,34,44,.55);transition:transform .35s var(--ease),box-shadow .35s var(--ease)}
.taped li:hover{transform:rotate(0) translateY(-6px);box-shadow:0 22px 30px -20px rgba(24,34,44,.55)}
.taped li::before{content:"";position:absolute;left:50%;top:-12px;width:78px;height:24px;transform:translateX(-50%) rotate(-3deg);background:color-mix(in srgb,var(--hi) 55%,transparent);border-radius:2px}
.taped img{display:block;width:100%;height:auto;aspect-ratio:16/10;object-fit:cover;border-radius:3px;background:var(--surface2)}
.taped a{display:block;color:inherit;text-decoration:none;border-radius:4px}
.taped p{font:700 1rem/1.3 var(--f-display);margin:12px 4px 10px;letter-spacing:-.01em}
.taped .open{display:block;margin:12px 4px 0;font-weight:700;font-size:.88rem;color:var(--ink);text-decoration:underline;text-decoration-color:var(--hi);text-decoration-thickness:2px;text-underline-offset:.22em}
.taped li:has(a:active){transform:rotate(0) translateY(-2px) scale(.985);transition-duration:.08s}
.chip{display:inline-block;margin-left:4px;font:700 .76rem/1.3 var(--f-body);padding:3px 10px;border-radius:99px;background:var(--surface2);color:var(--muted)}

/* ---------- last page ---------- */
.letter{position:relative;max-width:700px;margin:40px auto 72px;padding:46px 52px 40px 76px;border-radius:6px 6px 22px 6px;background-color:var(--surface);background-image:linear-gradient(90deg,transparent 52px,var(--margin-rule) 52px 54px,transparent 54px),repeating-linear-gradient(transparent 0 31px,var(--page-grid) 31px 32px);box-shadow:var(--shadow);transform:rotate(-.5deg)}
.letter h2{font-size:clamp(1.9rem,3.6vw,2.6rem);margin-bottom:18px}
.letter p{font:400 1.12rem/32px var(--f-paper);margin:0 0 16px;max-width:52ch}
.letter .sign{font:700 1.2rem var(--f-display);margin:22px 0 0;color:var(--muted)}
.letter .sign::before{content:"— "}
.letter .nuri-slot{position:absolute;right:26px;top:-34px;transform:rotate(8deg)}
.letter .nuri-slot svg{width:76px;height:76px}
@media (max-width:640px){.letter{padding:34px 22px 30px 40px;margin:24px auto 48px;background-image:linear-gradient(90deg,transparent 24px,var(--margin-rule) 24px 26px,transparent 26px),repeating-linear-gradient(transparent 0 31px,var(--page-grid) 31px 32px)}.letter .nuri-slot{right:14px;top:-28px}.letter .nuri-slot svg{width:60px;height:60px}}
.lastpage{max-width:760px;margin:40px auto 30px;text-align:center;padding:20px 0 30px}
.lastpage .nuri{width:140px;height:auto;margin-bottom:12px}
.lastpage h2{font-size:clamp(2.4rem,5vw,4rem);margin-bottom:16px}
.lastpage p{font-size:1.15rem;color:var(--muted);max-width:46ch;margin:0 auto 28px}

.foot{max-width:1180px;margin:0 auto;padding:24px 26px 40px;display:flex;align-items:center;gap:22px;border-top:1.5px solid var(--line);font-size:.92rem}
.foot a{color:var(--muted);font-weight:700}

/* ---------- Nuri's own motion ---------- */
.nuri .bob{animation:bob 3.2s ease-in-out infinite;transform-origin:50% 90%}
.nuri .hop{animation:hop 1.6s var(--ease) infinite;transform-origin:50% 100%}
.nuri .tw{animation:tw 1.8s ease-in-out infinite;transform-box:fill-box;transform-origin:center}
@keyframes bob{50%{transform:translateY(-3px) rotate(-2deg)}}
@keyframes hop{0%,60%,100%{transform:none}25%{transform:translateY(-9px) scaleY(1.04)}45%{transform:scaleY(.94)}}
@keyframes tw{50%{transform:scale(.5) rotate(30deg);opacity:.5}}

/* the neuron's wires ink themselves in once */
.ready .wire:not(.out){animation:draw 1.1s var(--ease) both}
.ready .wire[data-i="1"]{animation-delay:.12s}
.ready .wire[data-i="2"]{animation-delay:.24s}
@keyframes draw{from{stroke-dashoffset:420}to{stroke-dashoffset:0}}

/* in the dark, highlighter ink sits under the whole word so the text can stay dark */
@media (prefers-color-scheme: dark){ :root:not([data-theme="light"]) .marker{background:linear-gradient(transparent 6%,var(--hi) 6% 97%,transparent 97%);color:var(--hi-ink)} :root:not([data-theme="light"]) .hl{background:color-mix(in srgb,var(--hi) 82%,var(--surface));color:var(--hi-ink)} }
:root[data-theme="dark"] .marker{background:linear-gradient(transparent 6%,var(--hi) 6% 97%,transparent 97%);color:var(--hi-ink)}
:root[data-theme="dark"] .hl{background:color-mix(in srgb,var(--hi) 82%,var(--surface));color:var(--hi-ink)}

/* ---------- smaller screens ---------- */
@media (max-width:1020px){
  .page{padding:40px 32px 36px}
  .margin{padding-left:74px;background-image:linear-gradient(90deg,transparent 46px,var(--margin-rule) 46px 48px,transparent 48px),linear-gradient(var(--page-grid) 1px,transparent 1px),linear-gradient(90deg,var(--page-grid) 1px,transparent 1px)}
  .weights{grid-template-columns:1fr}
  .eq{white-space:normal;line-height:1.7}
  .digit{grid-template-columns:1fr;grid-template-areas:"pad" "guess" "bars";justify-items:center}
  .pad{width:min(100%,300px)}
  .taped{grid-template-columns:repeat(2,1fr)}
  .stop{width:108px}
  .stop .lbl{font-size:.74rem}
  .stop .lbl small{display:none}
}
@media (max-width:820px){
  body{font-size:16px}
  main{padding:4px 14px 30px}
  .top{padding:12px 16px;gap:12px}
  .top nav{display:none}
  .top .key{margin-left:auto;padding:9px 14px;font-size:.92rem}
  .spread{grid-template-columns:1fr;grid-template-rows:auto 34px auto;margin:18px auto 48px}
  .page-left{border-radius:20px 20px 4px 4px;border:1.5px solid var(--line);border-bottom:0}
  .page-right{border-radius:4px 4px 20px 20px;border:1.5px solid var(--line);border-top:0}
  .binding{border:0;border-left:1.5px solid var(--line);border-right:1.5px solid var(--line);background-image:var(--rings-h);background-size:28px 34px;background-repeat:round no-repeat}
  .page{padding:30px 22px 28px}
  .margin{padding-left:52px;background-image:linear-gradient(90deg,transparent 32px,var(--margin-rule) 32px 34px,transparent 34px),linear-gradient(var(--page-grid) 1px,transparent 1px),linear-gradient(90deg,var(--page-grid) 1px,transparent 1px)}
  .page-left h1{font-size:clamp(2.15rem,9vw,2.8rem)}
  .lede{font-size:1.08rem}
  .actions{gap:16px;margin-top:24px}
  .sheet{padding:32px 20px 28px;margin:18px auto 48px;border-radius:20px}
  .sheet-head{grid-template-columns:1fr}
  .road{aspect-ratio:auto;height:var(--road-h,1100px)}
  .stop{width:auto;flex-direction:row;transform:translate(-23px,-50%);gap:12px}
  .stop .lbl,.stop.below .lbl{position:static;margin:0;font-size:.88rem;text-align:left;max-width:12em;background:none;padding:0}
  .stop .lbl small{display:block}
  .unitnote{padding:20px 20px 18px}
  .paperpage{padding:24px 20px 16px;transform:none}
  .taped{grid-template-columns:1fr 1fr;gap:20px 16px}
  .taped p{font-size:.9rem}
  .nin{font-size:.8rem;padding:8px 6px;min-width:0;width:25%}
  .verdict{font-size:.9rem}
  .eq{white-space:normal;line-height:1.7}
}
@media (max-width:420px){ .taped{grid-template-columns:1fr} }

@media (prefers-reduced-motion: reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{animation:none!important;transition-duration:.01ms!important}
}