@font-face{font-family:"IBM Plex Sans";font-weight:400;font-display:block;src:url(fonts/ibm-plex-sans-latin-400-normal.woff2) format("woff2")}
@font-face{font-family:"IBM Plex Sans";font-weight:400;font-style:italic;font-display:swap;src:url(fonts/ibm-plex-sans-latin-400-italic.woff2) format("woff2")}
@font-face{font-family:"IBM Plex Sans";font-weight:500;font-display:block;src:url(fonts/ibm-plex-sans-latin-500-normal.woff2) format("woff2")}
@font-face{font-family:"IBM Plex Sans";font-weight:600;font-display:block;src:url(fonts/ibm-plex-sans-latin-600-normal.woff2) format("woff2")}
@font-face{font-family:"IBM Plex Sans";font-weight:700;font-display:swap;src:url(fonts/ibm-plex-sans-latin-700-normal.woff2) format("woff2")}
@font-face{font-family:"IBM Plex Mono";font-weight:400;font-display:swap;src:url(fonts/ibm-plex-mono-latin-400-normal.woff2) format("woff2")}
@font-face{font-family:"IBM Plex Mono";font-weight:500;font-display:swap;src:url(fonts/ibm-plex-mono-latin-500-normal.woff2) format("woff2")}

:root{
  --ink:#1a2a3a; --ink-2:#475569; --ink-3:#64748b; --line:#e2e8f0; --line-2:#cbd5e1;
  --paper:#f7f8fa; --card:#fff; --navy:#1a2a3a; --accent:#2563eb;
  --mono:"IBM Plex Mono",ui-monospace,SFMono-Regular,Menlo,monospace;
  --sans:"IBM Plex Sans",system-ui,-apple-system,"Segoe UI",sans-serif;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:110px}
body{margin:0;background:var(--paper);color:var(--ink);font:16px/1.65 var(--sans);-webkit-font-smoothing:antialiased}
a{color:var(--accent)}
code{font-family:var(--mono);font-size:.86em;background:#eef2f7;border:1px solid #e2e8f0;border-radius:4px;padding:.08em .35em;white-space:nowrap}

/* top bar */
.topbar{position:sticky;top:0;z-index:20;background:rgba(26,42,58,.97);backdrop-filter:blur(6px);color:#e2e8f0}
.topbar-in{max-width:1240px;margin:0 auto;padding:0 24px;height:52px;display:flex;align-items:center;justify-content:space-between;gap:16px}
.brand{color:#fff;text-decoration:none;font-weight:600;letter-spacing:.01em;white-space:nowrap}
.brand span{color:#94a3b8;font-weight:400}
.topbar nav{display:flex;gap:18px}
.topbar nav a{color:#cbd5e1;text-decoration:none;font-size:.9rem}
.topbar nav a:hover{color:#fff}

/* hero */
.hero{background:var(--navy);color:#fff;position:relative;overflow:hidden}
.hero::before{content:"";position:absolute;inset:0;background:
  linear-gradient(transparent 31px,rgba(255,255,255,.05) 32px),linear-gradient(90deg,transparent 31px,rgba(255,255,255,.05) 32px);
  background-size:32px 32px;mask-image:linear-gradient(90deg,transparent,#000 60%)}
.hero::after{content:"";position:absolute;left:0;right:0;bottom:0;height:4px;background:var(--accent)}
.hero-in{position:relative;max-width:1240px;margin:0 auto;padding:40px 24px 44px}
.crumb{color:#94a3b8;text-decoration:none;font-size:.88rem}
.crumb:hover{color:#fff}
.kicker{font-family:var(--mono);font-size:.78rem;letter-spacing:.08em;text-transform:uppercase;color:var(--accent);margin:14px 0 6px;font-weight:500}
.hero .kicker{color:color-mix(in srgb,var(--accent) 55%,#fff)}
.hero h1{font-size:clamp(2rem,4.2vw,3rem);line-height:1.1;margin:0 0 12px;font-weight:700;letter-spacing:-.015em}
.lede{max-width:780px;color:#cbd5e1;font-size:1.08rem;margin:0}
.stats{display:flex;flex-wrap:wrap;gap:10px;margin-top:26px}
.stat{background:rgba(255,255,255,.07);border:1px solid rgba(255,255,255,.14);border-radius:10px;padding:9px 14px;min-width:120px}
.stat b{display:block;font-size:1.25rem;line-height:1.2;font-weight:600}
.stat span{font-size:.78rem;color:#94a3b8}

/* layout: centered prose column, figures and tables break out wider */
.layout{max-width:1240px;margin:0 auto;padding:28px 24px 40px}
.toc{position:sticky;top:52px;z-index:15;background:rgba(247,248,250,.96);backdrop-filter:blur(6px);border-bottom:1px solid var(--line)}
.toc-in{max-width:1240px;margin:0 auto;padding:0 24px;display:flex;align-items:center;gap:4px;overflow-x:auto;scrollbar-width:none}
.toc-in::-webkit-scrollbar{display:none}
.toc a{color:var(--ink-2);text-decoration:none;font-size:.86rem;padding:12px 10px 10px;border-bottom:2px solid transparent;white-space:nowrap}
.toc a:hover{color:var(--ink)}
.toc a.on{color:var(--accent);border-bottom-color:var(--accent);font-weight:500}
.toc-meta{margin-left:auto;padding-left:16px;font:500 .72rem var(--mono);text-transform:uppercase;letter-spacing:.06em;color:var(--ink-3);white-space:nowrap}
.toc-h{font-family:var(--mono);font-size:.72rem;text-transform:uppercase;letter-spacing:.08em;color:var(--ink-3);margin:0 0 10px}

/* prose */
.prose{min-width:0}
.prose>*{max-width:860px;margin-left:auto;margin-right:auto}
.prose>.diagram,.prose>.table-wrap,.prose>.next{max-width:none}
.prose>h2{font-size:1.6rem;line-height:1.25;margin-top:48px;margin-bottom:14px;letter-spacing:-.01em}
.prose>h2:first-child{margin-top:8px}
.prose>h3{font-size:1.15rem;margin-top:30px;margin-bottom:8px}
.prose p,.prose li{color:#24364a}
.prose>hr{border:0;border-top:1px solid var(--line);margin-top:44px;margin-bottom:0;max-width:none}
.prose ul,.prose ol{padding-left:1.3em}
.prose li{margin:4px 0}
.prose li>ul,.prose li>ol{margin:4px 0}
.prose strong{color:var(--ink)}
.prose>blockquote{margin-top:18px;margin-bottom:18px;padding:14px 18px;background:#fff;border:1px solid var(--line);border-left:4px solid var(--accent);border-radius:8px}
.prose blockquote p{margin:.3em 0}
.prose blockquote ul{margin:.3em 0}

/* tables */
.table-wrap{overflow-x:auto;margin:18px 0;border:1px solid var(--line);border-radius:10px;background:#fff}
table{border-collapse:collapse;width:100%;font-size:.9rem;line-height:1.5}
th,td{padding:10px 14px;text-align:left;vertical-align:top;border-bottom:1px solid var(--line)}
th{background:#f1f5f9;font-weight:600;color:var(--ink);white-space:nowrap}
tr:last-child td{border-bottom:0}
td:first-child{font-weight:500;color:var(--ink)}
tbody tr:nth-child(even) td{background:#fbfcfd}
td code{white-space:normal}

/* diagrams */
.diagram{margin:20px 0 22px;background:#fff;border:1px solid var(--line);border-radius:12px;overflow:hidden;box-shadow:0 1px 2px rgba(15,23,42,.04)}
.fig-bar{display:flex;align-items:center;justify-content:space-between;gap:10px;padding:8px 10px 8px 12px;border-bottom:1px solid var(--line);background:#fafbfc}
.tabs{display:flex;gap:4px;flex-wrap:wrap}
.tabs button,.expand,#zoom-close{font:500 .82rem var(--sans);border:1px solid transparent;background:transparent;color:var(--ink-2);padding:5px 12px;border-radius:7px;cursor:pointer}
.tabs button:hover{background:#eef2f7}
.tabs button[aria-selected=true]{background:var(--accent);color:#fff}
.fig-label{font:500 .78rem var(--mono);text-transform:uppercase;letter-spacing:.06em;color:var(--accent);padding-left:2px}
.expand{border-color:var(--line);background:#fff;white-space:nowrap}
.expand:hover{border-color:var(--line-2);color:var(--ink)}
.panel{padding:18px 16px;display:flex;justify-content:center;overflow-x:auto}
.panel.scroll{justify-content:flex-start}
.scroll-hint{font:500 .72rem var(--mono);color:var(--ink-3);text-transform:uppercase;letter-spacing:.05em;margin-left:auto;margin-right:10px;white-space:nowrap}
.panel[hidden]{display:none}
.panel svg{height:auto;display:block}
.panel svg{cursor:zoom-in}

/* zoom dialog */
#zoom{width:min(96vw,1800px);height:92vh;max-width:none;max-height:none;padding:0;border:0;border-radius:12px;box-shadow:0 30px 80px rgba(0,0,0,.35)}
#zoom::backdrop{background:rgba(15,23,42,.7)}
#zoom[open]{display:flex;flex-direction:column}
.zoom-bar{display:flex;justify-content:space-between;align-items:center;padding:10px 14px;border-bottom:1px solid var(--line);font-weight:600}
#zoom-close{border-color:var(--line)}
.zoom-body{flex:1;overflow:auto;padding:24px;background:#fff}
.zoom-body svg{max-width:none!important;height:auto}

/* next */
.next{margin-top:56px;padding-top:24px;border-top:1px solid var(--line)}
.next-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:14px}
.next-card{display:block;text-decoration:none;background:#fff;border:1px solid var(--line);border-top:3px solid var(--accent);border-radius:10px;padding:14px 16px;color:var(--ink)}
.next-card .kicker{display:block;margin:0 0 4px;font-size:.7rem}
.next-card b{display:block}
.next-card:hover{border-color:var(--line-2);border-top-color:var(--accent);box-shadow:0 4px 14px rgba(15,23,42,.06)}

/* home */
.hero-home .hero-in{padding:56px 24px 60px}
.cards{max-width:1240px;margin:-28px auto 0;padding:0 24px 48px;display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:20px;position:relative}
.card{display:flex;flex-direction:column;text-decoration:none;color:var(--ink);background:#fff;border:1px solid var(--line);border-radius:14px;overflow:hidden;box-shadow:0 2px 6px rgba(15,23,42,.05);transition:transform .15s,box-shadow .15s}
.card:hover{transform:translateY(-2px);box-shadow:0 10px 28px rgba(15,23,42,.10)}
.card-top{padding:22px 22px 4px;border-top:5px solid var(--accent);background:linear-gradient(180deg,var(--tint),#fff 85%)}
.card-top .kicker{margin:0 0 6px}
.card h2{margin:0 0 8px;font-size:1.4rem;letter-spacing:-.01em}
.card p{margin:0;color:var(--ink-2);font-size:.95rem}
.stats.small{margin:16px 22px 0;gap:8px}
.stats.small .stat{background:#f8fafc;border-color:var(--line);min-width:0;flex:1 1 40%;padding:7px 10px}
.stats.small .stat b{font-size:1.02rem;color:var(--ink)}
.stats.small .stat span{color:var(--ink-3);font-size:.72rem}
.card-list{margin:16px 22px 0;padding:0;list-style:none;font-size:.88rem;color:var(--ink-2)}
.card-list li{padding:5px 0;border-top:1px dashed var(--line)}
.card-list li::before{content:"▸ ";color:var(--accent)}
.card-foot{margin-top:auto;display:flex;justify-content:space-between;align-items:center;padding:14px 22px;border-top:1px solid var(--line);font-size:.85rem;color:var(--ink-3)}
.card-foot b{color:var(--accent)}

.foot{border-top:1px solid var(--line);color:var(--ink-3);font-size:.85rem}
.foot div{max-width:1240px;margin:0 auto;padding:20px 24px}
.foot a{color:var(--ink-2)}

/* hero buttons */
.hero-actions{display:flex;flex-wrap:wrap;gap:10px;margin-top:20px}
.btn{display:inline-block;font:500 .9rem var(--sans);padding:8px 16px;border-radius:8px;background:var(--accent);color:#fff;text-decoration:none;border:1px solid var(--accent);cursor:pointer}
.btn:hover{filter:brightness(1.12)}
.btn.ghost{background:transparent;color:#e2e8f0;border-color:rgba(255,255,255,.32)}
.btn.ghost:hover{border-color:#fff;color:#fff;filter:none}

/* acronyms: inline tooltips + definition lists */
abbr[title],abbr[data-tip]{text-decoration:underline dotted;text-decoration-color:color-mix(in srgb,var(--accent) 65%,transparent);text-decoration-thickness:1.5px;text-underline-offset:3px;cursor:help}
abbr[data-tip]:focus-visible{outline:2px solid var(--accent);outline-offset:2px;border-radius:2px}
.tip{position:fixed;z-index:60;max-width:min(340px,calc(100vw - 16px));background:#1a2a3a;color:#cbd5e1;font-size:.82rem;line-height:1.45;padding:8px 11px;border-radius:8px;box-shadow:0 10px 28px rgba(15,23,42,.28);pointer-events:none}
.tip b{display:block;color:#fff;font-weight:600;margin-bottom:2px}
.acro-note{color:var(--ink-3);font-size:.88rem}
.acro{display:grid;grid-template-columns:repeat(auto-fill,minmax(290px,1fr));gap:0 24px;margin:10px 0 0;padding:0}
.acro>div{display:grid;grid-template-columns:5.6em 1fr;gap:10px;padding:7px 0;border-top:1px dashed var(--line);align-items:baseline}
.acro>div[hidden]{display:none}
.acro dt{font:600 .86rem var(--mono);color:var(--accent);overflow-wrap:anywhere}
.acro dt a{color:inherit;text-decoration:none}
.acro dt a:hover{text-decoration:underline}
.acro dd{margin:0;font-size:.86rem;line-height:1.5;color:var(--ink-2)}
.acro dd b{color:var(--ink);font-weight:600}
.acro .used{display:block;margin-top:3px;font-size:.76rem;color:var(--ink-3)}
.acro .used a{color:var(--ink-2)}
.prose>.acro{max-width:none}

/* glossary page */
.gloss{max-width:1240px;margin:0 auto;padding:12px 24px 48px}
.gloss section[hidden]{display:none}
.gloss h2{font-size:1.3rem;margin:32px 0 6px;letter-spacing:-.01em}
.acro.big{grid-template-columns:repeat(auto-fill,minmax(360px,1fr))}
.acro.big>div{padding:10px 0}
.acro.big dd{font-size:.9rem}
.acro>div:target{background:color-mix(in srgb,var(--accent) 10%,#fff);border-radius:6px}
#gfilter{margin-left:auto;flex:0 0 220px;font:400 .88rem var(--sans);padding:6px 10px;border:1px solid var(--line-2);border-radius:7px;background:#fff;color:var(--ink)}
#gfilter:focus{outline:2px solid var(--accent);outline-offset:1px}
.gempty{color:var(--ink-3)}

/* cheatsheets */
.hero-cs .hero-in{padding:28px 24px 32px}
.hero-cs .stats{margin-top:20px}
.cs{max-width:1240px;margin:0 auto;padding:24px 24px 40px}
.cs>.diagram{margin-top:0}
.cs-grid{columns:3 340px;column-gap:16px}
.cs-card{break-inside:avoid;display:block;background:#fff;border:1px solid var(--line);border-top:3px solid var(--accent);border-radius:10px;padding:12px 16px 10px;margin:0 0 16px;font-size:.88rem;line-height:1.5}
.cs-card h2{font-size:1rem;line-height:1.3;margin:0 0 6px;letter-spacing:0}
.cs-card p{margin:.45em 0;color:#24364a}
.cs-card ul,.cs-card ol{margin:.35em 0;padding-left:1.25em;color:#24364a}
.cs-card li{margin:3px 0}
.cs-card li>ul{margin:2px 0}
.cs-card strong{color:var(--ink)}
.cs-card code{white-space:normal;overflow-wrap:break-word}
.cs-card .table-wrap{margin:8px 0;border-radius:8px}
.cs-card table{font-size:.8rem;line-height:1.45}
.cs-card th,.cs-card td{padding:5px 9px}
.cs-card th{white-space:normal}
.cs-card .acro{grid-template-columns:repeat(auto-fill,minmax(270px,1fr))}
.cs-card .acro-note{margin:.2em 0 .4em}
.cs-wide{columns:auto}

/* home: quick reference */
.quick{max-width:1240px;margin:0 auto;padding:0 24px 48px}
.quick-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:14px}
.next-card .qs{display:block;margin-top:3px;font-size:.8rem;color:var(--ink-3)}

@media (max-width:1000px){
  .cards{grid-template-columns:1fr}
  .toc-meta{display:none}
  .quick-grid{grid-template-columns:repeat(2,minmax(0,1fr))}
}
@media (max-width:600px){
  .topbar nav a:not(:first-child){display:none}
  .brand span{display:none}
  .panel{padding:10px 6px}
  .stat{min-width:0;flex:1 1 40%}
  .quick-grid{grid-template-columns:1fr}
  #gfilter{flex-basis:150px}
  .acro.big{grid-template-columns:1fr}
}
@media print{
  .topbar,.toc,.expand,.tabs,.next,#zoom,.tip,.hero-actions,.crumb{display:none!important}
  .panel[hidden]{display:flex!important}
  .layout{display:block}
  body{background:#fff}
  .hero{background:#fff;color:var(--ink)}
  .hero::before,.hero::after{display:none}
  .hero .lede{color:var(--ink-2)}
  .stat{border-color:var(--line)}
  .diagram,.table-wrap{break-inside:avoid}
  /* cheatsheet: two dense columns, first diagram tab only */
  @page{margin:11mm}
  .cs-page .hero-in{padding:0 0 8px}
  .cs-page .hero h1{font-size:20pt;margin:0 0 4px}
  .cs-page .hero .kicker{margin:0 0 2px}
  .cs-page .lede{display:none}
  .cs-page .stats{margin-top:6px}
  .cs-page .stat{padding:4px 9px}
  .cs-page .stat b{font-size:11pt}
  .cs-page .panel[hidden]{display:none!important}
  .cs-page .fig-bar{display:none}
  .cs-page .panel svg{max-height:2.6in;width:auto!important}
  .cs{padding:0;max-width:none}
  .cs-grid{columns:2;column-gap:10px}
  .cs-card{font-size:8.4pt;line-height:1.38;padding:7px 10px 5px;margin-bottom:9px;box-shadow:none}
  .cs-card h2{font-size:10pt}
  .cs-card table{font-size:7.6pt}
  .cs-card th,.cs-card td{padding:3px 6px}
  .acro dd,.acro dt{font-size:7.8pt}
  .acro>div{padding:3px 0;grid-template-columns:5em 1fr}
}