/* Shared primitives for all demo directions. Each direction sets the custom properties. */
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;text-size-adjust:100%;scroll-padding-top:var(--scroll-pad,24px)}
body{margin:0;background:var(--bg);color:var(--ink);font-family:var(--font-body);font-size:var(--fs-body);line-height:var(--lh-body);-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility;text-autospace:normal}
img,svg{max-width:100%}
img{height:auto;display:block}
a{color:inherit}
::selection{background:var(--sel);color:var(--ink)}
:focus-visible{outline:2px solid var(--focus);outline-offset:3px;border-radius:3px}
.skip{position:absolute;left:-9999px;top:8px;z-index:50;padding:8px 14px;background:var(--ink);color:var(--bg);border-radius:6px}
.skip:focus{left:12px}
.visually-hidden{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}

/* prose */
.prose{min-width:0;overflow-wrap:break-word}
.prose>*:first-child{margin-top:0}
.prose p{margin:0 0 var(--para)}
.prose h2,.prose h3,.prose h4{font-family:var(--font-head);color:var(--ink);font-weight:600;letter-spacing:0;text-wrap:balance;position:relative}
.prose h2{font-size:var(--fs-h2);line-height:1.35;margin:2.4em 0 .8em}
.prose h3{font-size:var(--fs-h3);line-height:1.45;margin:2em 0 .6em}
.prose h4{font-size:var(--fs-body);line-height:1.6;margin:1.8em 0 .5em}
.prose .anchor{margin-left:.35em;color:var(--soft);text-decoration:none;opacity:0;font-weight:400;transition:opacity .15s}
.prose h2:hover .anchor,.prose h3:hover .anchor,.prose h4:hover .anchor,.prose .anchor:focus-visible{opacity:.7}
.prose a:not(.anchor){color:var(--link);text-decoration:underline;text-decoration-color:var(--link-line);text-decoration-thickness:1px;text-underline-offset:.22em}
.prose a:not(.anchor):hover{text-decoration-color:currentColor}
.prose strong{font-weight:600;color:var(--ink)}
.prose u{text-decoration-color:var(--accent-line);text-decoration-thickness:2px;text-underline-offset:.25em}
.prose ul,.prose ol{margin:0 0 var(--para);padding-left:1.5em}
.prose li{margin:.3em 0}
.prose li>ul,.prose li>ol{margin:.3em 0}
.prose li::marker{color:var(--soft)}
.prose hr{border:0;border-top:1px solid var(--rule);margin:2.5em 0}
.prose :not(pre)>code{font-family:var(--font-mono);font-size:.86em;background:var(--code-tint);color:var(--ink);padding:.12em .38em;border-radius:4px;overflow-wrap:anywhere}
.prose blockquote.quote{margin:1.6em 0;padding:.2em 0 .2em 1.1em;border-left:1px solid var(--rule-strong);color:var(--ink-2)}
.prose blockquote.quote p:last-child{margin-bottom:0}
.prose del{color:var(--soft)}

/* tables */
.table-wrap{overflow-x:auto;margin:1.6em 0;-webkit-overflow-scrolling:touch}
.prose table{border-collapse:collapse;width:100%;font-size:var(--fs-small);line-height:1.6;font-variant-numeric:tabular-nums}
.prose th,.prose td{padding:.6em .8em;border-bottom:1px solid var(--rule);text-align:left;vertical-align:top}
.prose th{font-weight:600;border-bottom-color:var(--rule-strong);white-space:nowrap}

/* code */
.codeblock{margin:1.6em 0;border-radius:var(--code-radius);background:var(--code-bg);overflow:hidden;position:relative}
.codeblock pre{margin:0;padding:16px 18px;overflow-x:auto;font-family:var(--font-mono);font-size:var(--fs-code);line-height:1.6;background:transparent!important;tab-size:2}
.codeblock pre code{font-family:inherit}
.code-head{display:flex;align-items:center;gap:10px;padding:0 8px 0 16px;min-height:38px;font-family:var(--font-ui);font-size:13px;color:var(--code-soft);border-bottom:1px solid var(--code-rule)}
.code-lang{flex:1}
.copy{font:inherit;font-size:12.5px;color:var(--code-soft);background:transparent;border:1px solid var(--code-rule);border-radius:6px;padding:3px 10px;cursor:pointer;min-height:28px}
.copy:hover{color:var(--code-ink);border-color:var(--code-soft)}
.copy--float{position:absolute;top:8px;right:8px;opacity:0;transition:opacity .15s}
.codeblock:hover .copy--float,.copy--float:focus-visible{opacity:1}

/* math */
.math-display{overflow-x:auto;overflow-y:hidden;margin:1.4em 0;padding:.2em 0;position:relative}
.katex{font-size:1.06em}
.katex-display{margin:0}

/* figures */
.figure{margin:2em 0}
.figure .zoom{display:block;width:100%;padding:0;border:0;background:none;cursor:zoom-in;border-radius:inherit}
.figure img{width:100%;border-radius:var(--img-radius)}
.figure figcaption{font-family:var(--font-ui);font-size:var(--fs-small);line-height:1.6;color:var(--soft);margin-top:.7em}
.diagram svg{display:block;margin:0 auto}

/* callouts (no thick side borders: tinted panel + icon) */
.callout{margin:1.6em 0;padding:14px 18px 2px;border-radius:var(--callout-radius);background:var(--c-bg);border:1px solid var(--c-line)}
.callout-title{display:flex;align-items:center;gap:8px;margin:0 0 6px!important;font-family:var(--font-ui);font-size:var(--fs-small);font-weight:600;color:var(--c-ink)}
.callout .ico{width:18px;height:18px;flex:none}
.callout-body{font-size:.96em}
.callout-body>*:last-child{margin-bottom:14px}
.callout--note{--c-bg:var(--note-bg);--c-line:var(--note-line);--c-ink:var(--note-ink)}
.callout--important{--c-bg:var(--imp-bg);--c-line:var(--imp-line);--c-ink:var(--imp-ink)}
.callout--tip{--c-bg:var(--tip-bg);--c-line:var(--tip-line);--c-ink:var(--tip-ink)}
.callout--warning,.callout--caution{--c-bg:var(--warn-bg);--c-line:var(--warn-line);--c-ink:var(--warn-ink)}

/* TOC */
.toc-list,.toc-list ul{list-style:none;margin:0;padding:0}
.toc-list a{display:block;text-decoration:none;color:var(--soft)}
.toc-list a:hover{color:var(--ink)}
.toc-list a[aria-current]{color:var(--ink)}
details.toc-mobile{display:none}
details.toc-mobile summary{cursor:pointer;list-style:none;display:flex;align-items:center;gap:8px;font-family:var(--font-ui);font-size:15px;font-weight:600;min-height:44px}
details.toc-mobile summary::-webkit-details-marker{display:none}
details.toc-mobile summary .ico{width:18px;height:18px}
details.toc-mobile summary .chev{margin-left:auto;transition:transform .2s}
details.toc-mobile[open] summary .chev{transform:rotate(90deg)}
details.toc-mobile .toc-list{padding:4px 0 10px;max-height:60vh;overflow:auto}
details.toc-mobile .toc-list a{padding:7px 0;font-size:15px;line-height:1.5}
details.toc-mobile .t3 a{padding-left:1.1em;font-size:14px}

/* lightbox */
.lightbox{border:0;padding:0;background:transparent;max-width:96vw;max-height:94vh}
.lightbox::backdrop{background:rgb(20 20 20 / .82)}
.lightbox img{max-width:96vw;max-height:90vh;width:auto;border-radius:8px;background:#fff}
.lightbox-close{position:fixed;top:14px;right:16px;font:14px/1 var(--font-ui);color:#fff;background:rgb(0 0 0 / .5);border:1px solid rgb(255 255 255 / .3);border-radius:8px;padding:10px 14px;cursor:pointer}

@media (prefers-reduced-motion:reduce){*{transition:none!important;scroll-behavior:auto!important}}
@media (max-width:640px){.codeblock{border-radius:var(--code-radius-m,var(--code-radius))}}

/* ---- emphasis system: each device has one job ----
   strong  = key term (weight only, no colour)
   u       = key sentence (highlighter band in --mark)
   callout--important = the section's conclusion (body size, 600 title) */
.prose u{text-decoration:none;background:linear-gradient(transparent 58%,var(--mark) 58%,var(--mark) 92%,transparent 92%);padding:0 .05em;-webkit-box-decoration-break:clone;box-decoration-break:clone}
.prose .callout-body{font-size:1em}

/* links: internal = plain underline; external = muted underline + outbound mark */
.prose a.ext{text-decoration-style:solid;text-decoration-color:var(--ext-line,var(--rule-strong))}
.prose a.ext .extico{width:.68em;height:.68em;margin-left:.18em;vertical-align:.02em;color:var(--soft)}
.prose a.int{text-decoration-color:var(--link-line);text-decoration-thickness:1.5px}

/* rich link previews (transparent, thin rule) */
.linkcards{display:grid;gap:10px;margin:-.2em 0 calc(var(--para) + .4em)}
.prose a.linkcard{display:flex;gap:14px;align-items:flex-start;padding:14px 16px;border:1px solid var(--rule);border-radius:var(--lc-radius,10px);background:transparent;text-decoration:none;color:inherit;font-family:var(--font-ui);line-height:1.5;transition:border-color .15s}
.prose a.linkcard:hover{border-color:var(--rule-strong)}
.lc-fav{width:20px;height:20px;border-radius:4px;margin-top:2px;flex:none}
.lc-text{display:grid;gap:2px;min-width:0}
.lc-host{font-size:12.5px;color:var(--soft)}
.lc-title{font-size:15px;font-weight:600;color:var(--ink)}
.lc-desc{font-size:13.5px;color:var(--soft);display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}

/* figure captions: muted, centred */
.figure figcaption{text-align:center}
.fignum{color:var(--soft)!important;font-weight:500!important;margin-right:.6em}
a,button,summary{touch-action:manipulation;-webkit-tap-highlight-color:transparent}
.lightbox{overscroll-behavior:contain}
.prose [id]{scroll-margin-top:var(--scroll-pad,24px)}