/* ══════════════════════════════════════════════════════════════
   FastAPI for AI Engineers — cream / red theme
   ══════════════════════════════════════════════════════════════ */

:root {
  /* Cream palette */
  --cream-50:#fdf9f0;
  --cream-100:#faf3e4;
  --cream-200:#f4ead6;
  --cream-300:#eadcc0;
  --cream-400:#d9c6a4;

  /* Red palette */
  --red-600:#c1192e;
  --red-700:#a5112a;
  --red-800:#84102a;
  --red-900:#5c0e22;
  --red-950:#3c0815;
  --rose:#f3c8cf;

  /* Neutrals */
  --ink:#2b1f12;
  --ink-soft:#6b5a44;
  --muted:#8a7860;
  --line:rgba(161,17,42,.14);
  --line-strong:rgba(161,17,42,.28);

  /* Decorative */
  --gold:#b78a2c;

  --font-ui:'Inter',system-ui,sans-serif;
  --font-display:'Fraunces',Georgia,serif;
  --font-code:'JetBrains Mono',ui-monospace,monospace;

  --shadow-sm:0 1px 2px rgba(92,14,34,.06),0 1px 3px rgba(92,14,34,.08);
  --shadow-md:0 4px 14px rgba(92,14,34,.10);
  --shadow-lg:0 16px 40px rgba(92,14,34,.16);
}

* { box-sizing:border-box; }
html { scroll-behavior:smooth; }
body {
  margin:0;
  font-family:var(--font-ui);
  background:var(--cream);
  color:var(--ink);
  line-height:1.7;
  -webkit-font-smoothing:antialiased;
}
a { color:var(--red-700); text-decoration:none; }
a:hover { text-decoration:underline; }
::selection { background:var(--rose, var(--red-600)); color:#fff; }

/* Scrollbar */
::-webkit-scrollbar{width:11px;height:11px}
::-webkit-scrollbar-track{background:var(--cream-200)}
::-webkit-scrollbar-thumb{background:var(--cream-400);border-radius:6px;border:2px solid var(--cream-200)}
::-webkit-scrollbar-thumb:hover{background:var(--red-800)}

/* ── Reading progress ── */
#progress{position:fixed;top:0;left:0;height:3px;width:0;background:linear-gradient(90deg,var(--red-700),var(--red-600));z-index:120;transition:width .08s linear}

/* ── Topbar ── */
.topbar{position:sticky;top:0;z-index:100;display:flex;align-items:center;height:58px;padding:0 20px;background:rgba(250,243,228,.86);backdrop-filter:blur(10px);border-bottom:1px solid var(--line-strong)}
.topbar-inner{width:100%;display:flex;align-items:center;gap:14px;justify-content:space-between}
.nav-toggle{display:flex;flex-direction:column;gap:5px;padding:10px 8px;background:none;border:0;cursor:pointer;border-radius:8px}
.nav-toggle span{width:22px;height:2px;background:var(--red-900);border-radius:2px;transition:.25s}
.nav-toggle[aria-expanded="true"] span:nth-child(1){transform:translateY(7px) rotate(45deg)}
.nav-toggle[aria-expanded="true"] span:nth-child(2){opacity:0}
.nav-toggle[aria-expanded="true"] span:nth-child(3){transform:translateY(-7px) rotate(-45deg)}
.topbar-title{font-weight:600;font-size:.95rem}
.crumb{color:var(--muted);font-weight:500}
.topbar-link{font-size:.85rem;display:inline-flex;align-items:center;gap:6px;padding:.4rem .8rem;border:1px solid var(--line-strong);border-radius:999px}

/* ── Layout ─────────────────────────────────────────────── */
.layout{display:flex;min-height:calc(100vh - 58px)}

/* Sidebar */
.sidebar{position:sticky;top:58px;height:calc(100vh - 58px);width:300px;flex-shrink:0;display:flex;flex-direction:column;color:#f6ead6;
  background:linear-gradient(180deg,var(--red-800) 0%,var(--red-900) 55%,var(--red-950) 100%);
  box-shadow:var(--shadow-lg);overflow:hidden;transition:width .25s ease}
.sidebar.dragging{transition:none}

/* Resize handle (draggable right edge) */
.resize{position:absolute;top:0;right:0;width:7px;height:100%;cursor:col-resize;z-index:6}
.resize::after{content:"";position:absolute;top:0;right:2px;width:2px;height:100%;background:transparent;transition:background .15s}
.resize:hover::after,.resize:active::after{background:var(--red-600)}
.resize:active{cursor:col-resize}

/* Collapse toggle button (desktop) */
.collapse-btn{display:flex;align-items:center;justify-content:center;gap:8px;margin:10px 14px 16px;padding:.55rem;border:1px solid rgba(255,255,255,.16);background:rgba(255,255,255,.06);color:#f0dcd0;font:600 .8rem var(--font-ui);border-radius:9px;cursor:pointer;transition:background .15s}
.collapse-btn:hover{background:rgba(255,255,255,.12)}
.collapse-btn .cb-ico{transition:transform .25s}
.brand{display:flex;align-items:center;gap:12px;padding:22px 20px;border-bottom:1px solid rgba(255,255,255,.12)}
.brand-mark{font-size:1.5rem;width:44px;height:44px;display:grid;place-items:center;background:rgba(255,255,255,.10);border-radius:12px;border:1px solid rgba(255,255,255,.16)}
.brand-name{font-family:var(--font-display);font-weight:700;font-size:1.02rem;line-height:1.15;letter-spacing:.2px}
.brand-sub{font-size:.74rem;color:#e7c9cf;margin-top:2px}
.nav-search-wrap{padding:14px 16px 6px}
#search{width:100%;padding:.5rem .75rem;border-radius:10px;border:1px solid rgba(255,255,255,.18);background:rgba(0,0,0,.18);color:#f6ead6;font-size:.85rem;outline:none}
#search::placeholder{color:#d9b6bd}#search:focus{border-color:#f28bcf}

.nav{flex:1;overflow-y:auto;padding:8px 12px 20px}
.nav::-webkit-scrollbar{width:8px}
.nav::-webkit-scrollbar-thumb{background:rgba(255,255,255,.18)}
.nav-group{margin:2px 0}
.nav-item{display:flex;align-items:center;gap:10px;width:100%;text-align:left;padding:.62rem .7rem;margin:2px 0;border:0;border-radius:9px;background:none;color:#f3e0d2;font:500 .88rem var(--font-ui);cursor:pointer;transition:background .15s}
.nav-item .ni-ico{font-size:1rem;width:20px;text-align:center}
.nav-item:hover{background:rgba(255,255,255,.09)}
.nav-item.active{background:var(--red-600);color:#fff;box-shadow:0 4px 12px rgba(0,0,0,.22)}
.nav-parent{justify-content:flex-start}
.nav-parent .chev{margin-left:auto;font-size:.6rem;color:#d9b7bd;transform:rotate(0deg);transition:transform .2s}
.nav-parent.open .chev{transform:rotate(90deg)}
.toc{list-style:none;margin:0;max-height:0;overflow:hidden;transition:max-height .3s ease}
.toc.open{max-height:600px}
.toc li{}
.toc a{display:block;padding:5px 12px 5px 22px;font-size:.82rem;color:#e6cdbf;border-left:1px solid rgba(255,255,255,.14);margin:0 6px 0 34px;transition:.15s}
.toc a:hover{color:#fff}
.toc a.active{color:#fff;border-left-color:var(--red-600);font-weight:600}
.toc a.pl{font-weight:600}
.sidebar-foot{padding:14px 20px;font-size:.78rem;border-top:1px solid rgba(255,255,255,.12);display:flex;gap:8px;align-items:center;color:#cbb0a2}
.sidebar-foot a{color:#e9c8d0}
.sidebar-foot a:hover{color:#fff}
.sidebar-foot .dot{opacity:.6}

.backdrop{position:fixed;inset:0;background:rgba(44,10,18,.4);opacity:0;pointer-events:none;z-index:40;transition:opacity .25s}

/* ── Content ────────────────────────────────────────────── */
.content{flex:1;min-width:0;padding:0 18px 60px;max-width:900px;margin:0 auto}

/* Hero */
.hero{padding:56px 8px 34px;text-align:center}
.hero-kicker{display:inline-block;font-size:.78rem;letter-spacing:.12em;text-transform:uppercase;color:var(--red-700);font-weight:600;border:1px solid var(--line-strong);padding:.3rem .9rem;border-radius:999px;background:var(--cream-200)}
.hero h1{font-family:var(--font-display);font-weight:700;font-size:clamp(1.9rem,4.2vw,3.1rem);line-height:1.12;margin:.9rem 0 .8rem;color:var(--red-950)}
.hero h1 .hl{position:relative;color:var(--red-700)}
.hero h1 .hl::after{content:"";position:absolute;left:0;right:0;bottom:.06em;height:.45em;background:var(--rose-1);opacity:.35;border-radius:4px;z-index:-1}
.hero-sub{max-width:640px;margin:0 auto 26px;color:var(--ink-soft,var(--ink-soft,#6b5a44));font-size:1.05rem}
.hero-actions{display:flex;gap:12px;justify-content:center;flex-wrap:wrap}
.sec-title{margin:46px auto -2px;max-width:640px;font-family:var(--font-display);font-weight:700;font-size:1.5rem;color:var(--red-900);border-bottom:2px solid var(--line-strong);padding-bottom:6px;width:100%}
.lead{max-width:640px;margin:1rem auto;color:var(--ink-soft,var(--ink-soft));font-size:1.03rem}
.pipeline-note{max-width:640px;margin:14px auto;text-align:center;color:var(--muted);font-size:.92rem}

/* Buttons */
.btn{display:inline-flex;align-items:center;gap:8px;padding:.68rem 1.3rem;border-radius:12px;font-weight:600;font-size:.93rem;cursor:pointer;transition:.18s;border:1px solid transparent;text-decoration:none}
.btn-red{background:var(--red-700);color:#fff;box-shadow:0 6px 16px rgba(161,17,42,.28)}
.btn-red:hover{background:var(--red-800);transform:translateY(-1px);text-decoration:none}
.btn-ghost{background:var(--cream-200);color:var(--red-800);border-color:var(--line-strong)}
.btn-ghost:hover{background:var(--cream-300);text-decoration:none}
.btn-outline{background:none;color:var(--red-700);border-color:var(--line-strong)}
.btn-outline:hover{background:var(--cream-200);text-decoration:none}

/* Cards */
.card-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:16px;max-width:860px;margin:18px auto 0}
.card{background:var(--cream-200);border:1px solid var(--line-strong);border-radius:16px;padding:22px 20px;box-shadow:var(--shadow-sm);transition:.2s;position:relative;overflow:hidden}
.card::before{content:"";position:absolute;top:0;left:0;right:0;height:4px;background:linear-gradient(90deg,var(--red-600),var(--red-800))}
.card:hover{transform:translateY(-4px);box-shadow:var(--shadow-md)}
.card-ico{font-size:1.6rem}
.card h3{font-family:var(--font-display);font-size:1.12rem;margin:10px 0 6px;color:var(--red-900)}
.card p{margin:0;font-size:.9rem;color:var(--ink-soft,var(--ink-soft))}
.card code{font-family:var(--font-code);font-size:.82em;background:var(--cream-300);padding:.1em .35em;border-radius:5px}

/* Pipeline */
.pipeline{display:flex;flex-wrap:wrap;align-items:center;justify-content:center;gap:8px;max-width:820px;margin:18px auto 8px;background:var(--cream-200);border:1px solid var(--line-strong);border-radius:18px;padding:20px}
.pl-node{font-weight:600;font-size:.92rem;padding:.5rem .95rem;border-radius:10px;background:var(--cream);border:1px solid var(--line-strong);color:var(--red-900)}
.pl-node-last{background:var(--red-700);color:#fff;border-color:var(--red-700)}
.pl-arr{color:var(--red-600);font-weight:700}

/* Prose (rendered markdown) */
.doc-head{padding:26px 8px 10px;border-bottom:2px solid var(--line-strong);margin-bottom:8px}
.doc-kicker{font-size:.8rem;letter-spacing:.14em;text-transform:uppercase;color:var(--red-700);font-weight:600}
.doc-head h1{font-family:var(--font-display);font-size:2rem;color:var(--red-900);margin:.4rem 0 0;line-height:1.15}
.prose{padding:8px 4px;max-width:820px;margin:0 auto}
.prose h1,.prose h2,.prose h3,.prose h4{font-family:var(--font-display);color:var(--red-900);line-height:1.2;scroll-margin-top:80px}
.prose h1{font-size:1.9rem;border-bottom:2px solid var(--line-strong);padding-bottom:.35rem}
.prose h2{font-size:1.45rem;margin-top:2.2rem;padding-left:.6rem;border-left:5px solid var(--red-600)}
.prose h3{font-size:1.12rem;margin-top:1.8rem}
.prose p{color:var(--ink);margin:.7rem 0}
.prose strong{color:var(--red-800)}
.prose ul,.prose ol{padding-left:1.4rem}
.prose li{margin:.32rem 0}
.prose blockquote{border-left:4px solid var(--red-600);background:var(--cream-200);margin:1rem 0;padding:.6rem 1rem;border-radius:0 10px 10px 0;color:var(--ink-soft);font-style:italic}
.prose code:not(pre code){font-family:var(--font-code);font-size:.86em;background:var(--cream-300);color:var(--red-800);padding:.12em .4em;border-radius:5px}
.prose pre{position:relative;background:#011627;border-radius:12px;padding:14px 14px 14px 14px;overflow:auto;box-shadow:var(--shadow-md);border:1px solid rgba(255,255,255,.06)}
.prose pre code{font-family:var(--font-code);font-size:.86rem;line-height:1.6;color:#d6deeb}
.prose pre .copy{position:absolute;top:8px;right:8px;background:rgba(255,255,255,.08);border:1px solid rgba(255,255,255,.14);color:#fff;font-size:.72rem;padding:.22rem .55rem;border-radius:6px;cursor:pointer;opacity:0;transition:.18s}
.prose pre:hover .copy{opacity:1}
.prose table{width:100%;border-collapse:separate;border-spacing:0;margin:1.2rem 0;font-size:.9rem;border:1px solid var(--line-strong);border-radius:12px;overflow:hidden}
.prose th{background:var(--red-800);color:#fff;text-align:left;font-weight:600;padding:.6rem .9rem}
.prose td{padding:.6rem .9rem;border-top:1px solid var(--line-strong);vertical-align:top}
.prose tr:nth-child(even) td{background:var(--cream-200)}
.prose tr:hover td{background:var(--cream-300)}
.prose hr{border:none;height:2px;background:linear-gradient(90deg,transparent,var(--line-strong),transparent);margin:2rem 0}
.prose img{max-width:100%;border-radius:12px}
.prose .table-wrap{overflow-x:auto}

/* Footer */
.footer{margin-top:60px;padding:24px 0 10px;border-top:1px solid var(--line-strong);text-align:center;color:var(--muted);font-size:.85rem}

/* To-top */
.to-top{position:fixed;right:22px;bottom:22px;width:44px;height:44px;border-radius:50%;border:0;background:var(--red-700);color:#fff;font-size:1.1rem;cursor:pointer;box-shadow:var(--shadow-md);opacity:0;pointer-events:none;transform:translateY(10px);transition:.25s;z-index:110}
.to-top.show{opacity:1;pointer-events:auto;transform:translateY(0)}
.to-top:hover{background:var(--red-800)}

/* Responsive */
@media (min-width:901px){
  /* Collapsed sidebar — icon rail only (desktop) */
  .sidebar.collapsed{width:70px}
  .sidebar.collapsed .brand{justify-content:center;padding:22px 0}
  .sidebar.collapsed .brand-name,
  .sidebar.collapsed .brand-sub,
  .sidebar.collapsed .nav-item span:not(.ni-ico),
  .sidebar.collapsed .chev,
  .sidebar.collapsed .toc,
  .sidebar.collapsed .sidebar-foot,
  .sidebar.collapsed #search,
  .sidebar.collapsed .collapse-btn .cb-txt{display:none}
  .sidebar.collapsed .nav-item{justify-content:center;padding:.7rem}
  .sidebar.collapsed .collapse-btn{padding:.55rem 0;margin:10px 6px 16px}
  .sidebar.collapsed .collapse-btn .cb-ico{transform:rotate(180deg)}
}
@media (max-width:900px){
  .sidebar{position:fixed;left:0;top:58px;height:calc(100vh - 58px);width:300px !important;transform:translateX(-100%);transition:transform .28s ease;z-index:60}
  .resize,.collapse-btn{display:none}
  .sidebar.open{transform:translateX(0)}
  .content{padding:0 16px 60px}
  .backdrop.show{opacity:1;pointer-events:auto}
  .nav-toggle{display:flex}
}
@media (min-width:901px){ .nav-toggle{display:none} .backdrop{display:none} }