/* =========================================================
   Di's Notes · shared styles
   Look: 3Blue1Brown-style blackboard. Dark ground, faint
   number-plane grid, Manim palette, LaTeX-like serif.
   Colour is semantic in every figure:
     yellow = draft / guess (q)   blue  = target / confirmed (p)
     red    = rejected / wrong    green = resampled / corrected
   ========================================================= */
:root{
  --bg:#0c0d10;
  --panel:#121418;
  --panel2:#181b21;
  --hair:#23272f;
  --hair2:#30353f;
  --fg:#ebe9e2;
  --soft:#c9c8c1;
  --muted:#8f949c;
  --dim:#5a5f68;
  --blue:#58c4dd;
  --yellow:#f4d345;
  --red:#fc6255;
  --green:#83c167;
  --math:"STIX Two Text","Noto Serif SC","Songti SC",serif;
  --serif:"STIX Two Text","Noto Serif SC","Songti SC","Source Han Serif SC","SimSun",serif;
  --cn:"Noto Serif SC","Songti SC","Source Han Serif SC","SimSun",serif;
  --mono:"JetBrains Mono",ui-monospace,"SF Mono",Consolas,Menlo,monospace;
  color-scheme:dark;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--fg);font-family:var(--serif);font-size:17.5px;line-height:1.9;-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
[hidden]{display:none!important}
img{max-width:100%}
.gutter{padding-left:max(16px,env(safe-area-inset-left,0px));padding-right:max(16px,env(safe-area-inset-right,0px))}
.wrap{max-width:1072px;margin:0 auto}
.prose{max-width:40em;margin:0 auto}
p{margin:0 0 1.15em}
h1,h2,h3{font-family:var(--cn);font-weight:900;text-wrap:balance;line-height:1.25;margin:0}
a{color:var(--blue);text-decoration:none;border-bottom:1px solid rgba(88,196,221,.35)}
a:hover{border-bottom-color:var(--blue)}
b{font-weight:600;color:#fff}
b.B{color:var(--blue)} b.Y{color:var(--yellow)} b.R{color:var(--red)} b.G{color:var(--green)}
.cB{color:var(--blue)} .cY{color:var(--yellow)} .cR{color:var(--red)} .cG{color:var(--green)} .cM{color:var(--muted)}
i.v{font-family:var(--math);font-style:italic}
.num{font-family:var(--math);font-variant-numeric:tabular-nums lining-nums}
code{font-family:var(--mono);font-size:.86em;background:rgba(255,255,255,.05);border:1px solid var(--hair);border-radius:5px;padding:1px 5px}

/* ---------- site header / footer ---------- */
.site-head{position:relative;z-index:3;border-bottom:1px solid var(--hair);background:rgba(12,13,16,.7);backdrop-filter:blur(6px)}
.site-head .wrap{display:flex;align-items:center;justify-content:space-between;gap:16px;padding-block:14px}
.brand{font-family:var(--math);font-size:20px;color:#fff;border:0;letter-spacing:.01em}
.brand i{color:var(--blue);font-style:italic}
.site-nav{display:flex;gap:22px;font-family:var(--cn);font-size:14.5px}
.site-nav a{color:var(--soft);border:0}
.site-nav a:hover,.site-nav a.on{color:#fff}
.site-foot{border-top:1px solid var(--hair);margin-top:96px}
.site-foot .wrap{display:flex;flex-wrap:wrap;gap:8px 24px;justify-content:space-between;padding-block:26px 40px;color:var(--muted);font-size:14px;font-family:var(--cn)}

/* ---------- figures ---------- */
/* figures sit at reading width so they support the text instead of dominating it;
   add class="big" to a <figure> only when the figure is the main content */
figure{margin:34px auto 40px;max-width:44em}
figure.big{max-width:1040px}
.fig{position:relative;background:linear-gradient(180deg,var(--panel),#0f1114);border:1px solid var(--hair);border-radius:12px;padding:20px 22px 18px;box-shadow:0 1px 0 rgba(255,255,255,.03) inset,0 30px 60px -40px rgba(0,0,0,.8)}
figcaption{display:flex;gap:12px;align-items:baseline;margin:12px 0 0;padding:0 4px;color:var(--muted);font-size:14px;line-height:1.75}
figcaption .fn{font-family:var(--mono);font-size:11.5px;letter-spacing:.14em;color:var(--blue);white-space:nowrap}
.fig-h{display:flex;flex-wrap:wrap;gap:10px 16px;align-items:center;justify-content:space-between;margin-bottom:12px}
.fig-title{font-family:var(--cn);font-size:15px;font-weight:600;color:var(--fg)}
.fig-title small{font-family:var(--mono);font-weight:400;font-size:11.5px;letter-spacing:.12em;color:var(--muted);margin-left:10px;text-transform:uppercase}
svg.viz{display:block;width:100%;height:auto;overflow:visible}
svg.viz text{font-family:var(--math);fill:var(--muted);font-size:15px}
svg.viz text.it{font-style:italic}
svg.viz text.cn{font-family:var(--cn)}
svg.viz text.word{font-family:var(--cn);fill:var(--fg);font-size:22px;font-weight:600}
.wide{overflow-x:auto;overflow-y:hidden;-webkit-overflow-scrolling:touch;scrollbar-width:thin}
.wide > svg.viz{min-width:560px}
.sub-h{font-family:var(--mono);font-size:11.5px;letter-spacing:.14em;text-transform:uppercase;color:var(--muted);margin:22px 0 8px;display:flex;gap:12px;align-items:center}
.sub-h::after{content:"";flex:1;height:1px;background:var(--hair)}
.readout{font-family:var(--cn);font-size:15.5px;color:var(--soft);margin-top:8px;min-height:1.9em}
.readout .num{color:#fff;font-size:17.5px}

/* ---------- controls ---------- */
.btn{font:inherit;font-family:var(--cn);font-size:14px;line-height:1;color:var(--soft);background:rgba(255,255,255,.02);border:1px solid var(--hair2);border-radius:999px;padding:9px 16px;cursor:pointer;transition:border-color .2s,background .2s,color .2s,transform .1s;white-space:nowrap}
.btn:hover{border-color:var(--muted);color:var(--fg)}
.btn:active{transform:translateY(1px)}
.btn:focus-visible,input:focus-visible,a:focus-visible{outline:2px solid var(--blue);outline-offset:3px}
.btn.primary{border-color:rgba(88,196,221,.7);color:var(--blue);background:rgba(88,196,221,.07)}
.btn.primary:hover{background:rgba(88,196,221,.14);border-color:var(--blue)}
.btn:disabled{opacity:.3;cursor:default}
.seg-group{display:inline-flex;flex-wrap:wrap;border:1px solid var(--hair2);border-radius:999px;padding:3px;gap:2px;background:rgba(255,255,255,.02)}
.seg-group .btn{border:0;padding:7px 14px;background:transparent}
.seg-group .btn.on{background:var(--panel2);color:var(--blue);box-shadow:0 0 0 1px rgba(88,196,221,.5) inset}
.row{display:flex;flex-wrap:wrap;gap:8px;align-items:center}
.legend{display:flex;flex-wrap:wrap;gap:6px 18px;font-size:13.5px;color:var(--muted);font-family:var(--cn)}
.legend span{display:inline-flex;align-items:center;gap:7px}
.legend i{width:10px;height:10px;border-radius:2px;display:inline-block}
.ctrl{display:grid;grid-template-columns:max-content minmax(0,1fr) 4.5em;gap:4px 18px;align-items:center;font-size:15px}
.ctrl label{color:var(--soft);white-space:nowrap;font-family:var(--cn)}
.ctrl label i{font-family:var(--math);font-style:italic;color:var(--fg);margin-left:4px}
.ctrl output{font-family:var(--math);font-size:18px;text-align:right;font-variant-numeric:tabular-nums}
input[type=range]{--c:var(--blue);--p:50%;-webkit-appearance:none;appearance:none;width:100%;height:28px;background:transparent;cursor:pointer;margin:0;min-width:0}
input[type=range].y{--c:var(--yellow)}
input[type=range]::-webkit-slider-runnable-track{height:3px;border-radius:3px;background:linear-gradient(90deg,var(--c) 0 var(--p),var(--hair2) var(--p) 100%)}
input[type=range]::-webkit-slider-thumb{-webkit-appearance:none;width:18px;height:18px;border-radius:50%;background:var(--bg);border:2.5px solid var(--c);margin-top:-7.5px;box-shadow:0 0 0 5px rgba(0,0,0,.35);transition:transform .15s}
input[type=range]:hover::-webkit-slider-thumb{transform:scale(1.12)}
input[type=range]::-moz-range-track{height:3px;border-radius:3px;background:var(--hair2)}
input[type=range]::-moz-range-progress{height:3px;border-radius:3px;background:var(--c)}
input[type=range]::-moz-range-thumb{width:14px;height:14px;border-radius:50%;background:var(--bg);border:2.5px solid var(--c)}

/* ---------- tokens ---------- */
.tok{display:inline-block;font-family:var(--cn);font-size:19px;line-height:1.55;padding:1px 8px;margin:3px 2px;border:1.5px solid transparent;border-radius:6px;max-width:7em;overflow:hidden;white-space:nowrap;vertical-align:bottom;
  transition:color .35s,background-color .35s,border-color .35s,opacity .4s,max-width .45s,padding .45s,margin .45s,transform .35s;animation:pop .32s cubic-bezier(.2,.9,.3,1.2)}
@keyframes pop{from{transform:translateY(-9px) scale(.9);opacity:0}}
.tok.draft{color:var(--yellow);border-style:dashed;border-color:rgba(244,211,69,.6);background:rgba(244,211,69,.06)}
.tok.acc{color:var(--blue);background:rgba(88,196,221,.1);border-color:rgba(88,196,221,.18)}
.tok.rej{color:var(--red);text-decoration:line-through;background:rgba(252,98,85,.1);border-color:rgba(252,98,85,.35)}
.tok.fix{color:var(--green);background:rgba(131,193,103,.12);border-color:rgba(131,193,103,.55)}
.tok.gone{max-width:0;padding-left:0;padding-right:0;margin-left:0;margin-right:0;border-width:0;opacity:0}

/* ---------- article ---------- */
.post-head{position:relative;overflow:hidden;border-bottom:1px solid var(--hair)}
.post-head canvas{position:absolute;inset:0;width:100%;height:100%}
.post-head .wrap{position:relative;padding-block:72px 56px}
.eyebrow{font-family:var(--mono);font-size:12px;letter-spacing:.16em;text-transform:uppercase;color:var(--muted)}
.post-head h1{font-size:clamp(36px,6.4vw,64px);margin:14px 0 16px;color:#fff;max-width:16em}
.post-meta{font-family:var(--cn);font-size:14.5px;color:var(--muted);display:flex;flex-wrap:wrap;gap:6px 18px}
.post-meta .tag{color:var(--blue)}
.post-body h2{font-size:clamp(26px,3.8vw,34px);margin:72px 0 22px}
.post-body h2 .n{font-family:var(--math);font-style:italic;font-weight:400;color:var(--blue);margin-right:14px}
.post-body ol.steps{padding-left:0;list-style:none;counter-reset:s;margin:0 0 1.2em}
.post-body ol.steps>li{counter-increment:s;position:relative;padding-left:2.2em;margin-bottom:.6em}
.post-body ol.steps>li::before{content:counter(s);position:absolute;left:0;top:.05em;font-family:var(--math);font-style:italic;color:var(--blue);font-size:1.15em}
.callout{position:relative;margin:30px 0;padding:18px 22px;border-radius:10px;background:rgba(88,196,221,.05);border:1px solid rgba(88,196,221,.2)}
.callout.y{background:rgba(244,211,69,.045);border-color:rgba(244,211,69,.25)}
.callout .ct{font-family:var(--cn);font-weight:600;color:#fff;margin-bottom:6px}
.callout p:last-child{margin:0}
.pullquote{font-family:var(--cn);font-size:clamp(20px,2.6vw,25px);font-weight:600;line-height:1.7;text-align:center;margin:44px auto;max-width:22em;color:#fff}
.refs{font-size:14px;color:var(--muted);line-height:1.85;padding-left:1.2em;margin:8px 0 18px}
.refs a{color:var(--soft);border-bottom-color:var(--hair2)}
sup.ref a{font-family:var(--math);font-size:12px;border:0;padding:0 1px}

@media (max-width:720px){
  body{font-size:16.5px}
  .fig{padding:18px 14px 16px;border-radius:12px}
  .ctrl{grid-template-columns:auto minmax(0,1fr) 3.4em;gap:2px 10px}
  .site-nav{gap:16px}
}
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *{animation-duration:1ms!important;transition-duration:1ms!important;transition-delay:0ms!important}
}