/* Shared by every page: tokens, base, top bar and tabs, content pages. */
:root{
  --paper:#e8ecf1;--sheet:#f7f9fb;--ink:#0f1e33;--muted:#56637a;--rule:#c8d1dd;
  --accent:#2e3fbf;--accent-ink:#fff;--accent-soft:#dde2fa;--amber:#9a6412;--amber-soft:#f4e7d0;
  --green:#1f6b45;--green-soft:#dcefe3;--red:#9b2c2c;--red-soft:#f6dede;
  --serif:"Newsreader",Georgia,"Times New Roman",serif;
  --sans:"Instrument Sans",ui-sans-serif,system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;
  --r-sm:6px;--r-md:10px;--q:#4f6ef7;
}
@media (prefers-color-scheme:dark){:root{
  --paper:#0c1524;--sheet:#131e31;--ink:#e4e9f1;--muted:#97a3b8;--rule:#26344c;
  --accent:#93a0ff;--accent-ink:#0c1524;--accent-soft:#1d2650;--amber:#e3b25d;--amber-soft:#2e2615;
  --green:#7fd1a4;--green-soft:#15301f;--red:#f0a0a0;--red-soft:#3a1c1c;--q:#8ea2ff}}
*{box-sizing:border-box}
html,body{margin:0;background:var(--paper);color:var(--ink);font:16px/1.55 var(--sans);-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
button,input,textarea{font:inherit;color:inherit}
a{color:var(--accent)}
:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
[hidden]{display:none!important}
.wrap{max-width:1040px;margin:0 auto;padding:20px 20px 140px}
.narrow{max-width:680px;margin-left:auto;margin-right:auto}

/* top bar and tabs */
.bar{display:flex;align-items:center;gap:10px 22px;margin-bottom:56px;flex-wrap:wrap}
.brand{display:flex;align-items:center;gap:10px;color:inherit;text-decoration:none}
.mark{width:22px;height:22px;border:2px solid var(--ink);border-radius:50%;position:relative;flex:none}
.mark::after{content:"";position:absolute;inset:4px;border-radius:50%;background:var(--accent)}
.name{font-weight:700;font-size:21px;letter-spacing:-.02em;line-height:1}
.name .q{color:var(--q)}
.tabs{display:flex;gap:4px;flex-wrap:wrap}
.tabs a{color:var(--muted);text-decoration:none;font-size:14.5px;padding:6px 10px;border-radius:var(--r-sm)}
.tabs a:hover{color:var(--ink);background:var(--sheet)}
.tabs a[aria-current=page]{color:var(--ink);font-weight:600;box-shadow:inset 0 -2px 0 var(--accent);border-radius:0}
/* drop-down under a tab (Library) */
.tabs .dd{position:relative;display:inline-flex}
.tabs .dd>a::after{content:"";display:inline-block;width:0;height:0;margin-left:6px;border:4px solid transparent;border-top-color:currentColor;border-bottom:0;vertical-align:2px;opacity:.7}
.dd .menu{position:absolute;top:100%;left:0;z-index:60;min-width:200px;padding:6px;margin-top:2px;display:flex;flex-direction:column;gap:2px;
  background:var(--paper);border:1px solid var(--rule);border-radius:var(--r-md);box-shadow:0 12px 32px rgba(15,30,51,.14);
  opacity:0;visibility:hidden;transform:translateY(4px);transition:opacity .15s,transform .15s,visibility .15s}
.dd .menu::before{content:"";position:absolute;left:0;right:0;top:-8px;height:8px}
.dd:hover .menu,.dd:focus-within .menu{opacity:1;visibility:visible;transform:none}
.tabs .dd .menu a{white-space:nowrap;padding:8px 10px;font-weight:400}
.tabs .dd .menu a[aria-current=page]{box-shadow:none;border-radius:var(--r-sm);background:var(--sheet);font-weight:600}
.tabs .ddbtn{appearance:none;border:0;background:none;font:inherit;font-size:14.5px;color:var(--muted);padding:6px 10px;border-radius:var(--r-sm);cursor:pointer}
.tabs .ddbtn:hover{color:var(--ink);background:var(--sheet)}
.tabs .ddbtn::after{content:"";display:inline-block;width:0;height:0;margin-left:6px;border:4px solid transparent;border-top-color:currentColor;border-bottom:0;vertical-align:2px;opacity:.7}
.tabs .ddbtn.cur{color:var(--ink);font-weight:600;box-shadow:inset 0 -2px 0 var(--accent);border-radius:0}
.dd.open .menu{opacity:1;visibility:visible;transform:none}
@media (hover:none){.dd:not(.open) .menu{display:none}}
@media (max-width:640px){.dd .menu{left:auto;right:0;min-width:180px}}
/* sub-sections of a tab */
.subtabs{display:inline-flex;flex-wrap:wrap;gap:4px;padding:4px;margin:-24px 0 26px;border:1px solid var(--rule);border-radius:999px;background:var(--sheet)}
.subtabs a{color:var(--muted);text-decoration:none;font-size:14px;padding:6px 14px;border-radius:999px}
.subtabs a:hover{color:var(--ink)}
.subtabs a[aria-current=page]{background:var(--ink);color:var(--paper);font-weight:600}
@media (max-width:820px){.subtabs{margin-top:-12px}}
.proto{margin-left:auto;font-size:13px;color:var(--muted)}
.talk{margin-left:auto;font-size:13px;font-weight:600;line-height:1;padding:8px 14px;border-radius:999px;border:1px solid var(--ink);color:var(--ink);text-decoration:none;white-space:nowrap}
.talk:hover,.talk:focus-visible{background:var(--ink);color:var(--paper)}
@media (max-width:820px){.bar{margin-bottom:36px}}
@media (max-width:640px){
  .tabs{order:3;width:100%;margin-left:-10px}
  .proto{display:none}
}

/* content pages (About, Technology mapping) */
.page h1{font-family:var(--serif);font-weight:400;font-size:clamp(34px,4.6vw,52px);line-height:1.06;letter-spacing:-.02em;margin:0 0 18px}
.page .lead{font-size:18px;line-height:1.6;color:var(--muted);max-width:60ch;margin:0 0 40px}
.page h2{font-family:var(--serif);font-weight:400;font-size:28px;letter-spacing:-.01em;margin:44px 0 12px}
.page h3{font-size:16px;font-weight:600;margin:0 0 6px}
.page p,.page li{max-width:70ch}
.page ul{padding-left:20px}
.page li{margin:6px 0}
.muted{color:var(--muted)}
.fine{font-size:14px;color:var(--muted)}
.btn{appearance:none;border:0;border-radius:var(--r-sm);padding:13px 22px;background:var(--ink);color:var(--paper);font-weight:600;cursor:pointer;text-decoration:none;display:inline-block}
.grid2{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px}
.grid4{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:14px}
.card{background:var(--sheet);border:1px solid var(--rule);border-radius:var(--r-md);padding:18px 18px 16px}
.card p{margin:0;font-size:15px;color:var(--muted)}
.card .num{font-family:var(--serif);font-size:15px;color:var(--accent);margin-bottom:6px;display:block}
.callout{border-left:3px solid var(--accent);background:var(--sheet);padding:16px 18px;border-radius:0 var(--r-md) var(--r-md) 0;margin:18px 0}
.callout.amber{border-left-color:var(--amber)}
.callout p{margin:0 0 8px}.callout p:last-child{margin:0}
.cta{margin:48px 0 0;display:flex;gap:14px;align-items:center;flex-wrap:wrap}
@media (max-width:820px){.grid4{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media (max-width:560px){.grid2,.grid4{grid-template-columns:1fr}}

/* footer, all content pages */
.foot{margin:64px 0 0;padding-top:20px;border-top:1px solid var(--rule);display:flex;flex-wrap:wrap;gap:8px 20px;font-size:14px;color:var(--muted)}
.foot span{flex:1 1 320px}
.foot a{color:var(--muted)}
.foot a:hover{color:var(--ink)}