/* ============================================================
   Deep Dives — shared design system
   Dark, modern, responsive. No build step; plain CSS.
   ============================================================ */
:root {
  --bg: #0a0e17;
  --bg2: #0d1220;
  --card: #141a2b;
  --card2: #101728;
  --ink: #e8edf9;
  --muted: #93a0c0;
  --faint: #5f6d90;
  --accent: #5b8cff;
  --accent2: #9d7bff;
  --border: #222c47;
  --border2: #2c3860;

  /* semantic pipeline colors */
  --c-ingest: #f0a35e;
  --c-embed: #56c2b8;
  --c-store: #9d7bff;
  --c-retrieve: #5b8cff;
  --c-augment: #f0736e;
  --c-generate: #6ee7a8;

  --radius: 14px;
  --radius-sm: 9px;
  --maxw: 900px;
  --shadow: 0 12px 40px rgba(0,0,0,.35);
  --mono: "SF Mono", "JetBrains Mono", "Fira Code", Consolas, monospace;
  --sans: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--sans);
  background: radial-gradient(1200px 800px at 80% -10%, #16203a 0%, transparent 55%),
              radial-gradient(1000px 700px at -10% 10%, #1a1533 0%, transparent 50%),
              var(--bg);
  color: var(--ink);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

/* scroll progress bar */
#progress {
  position: fixed; top: 0; left: 0; height: 3px; width: 0%;
  background: linear-gradient(90deg, var(--accent), var(--accent2));
  z-index: 100; transition: width .1s linear;
}

/* ---------- top bar ---------- */
.topbar {
  position: sticky; top: 0; z-index: 50;
  backdrop-filter: blur(10px);
  background: rgba(10,14,23,.72);
  border-bottom: 1px solid var(--border);
}
.topbar .row {
  max-width: 1180px; margin: 0 auto; padding: 12px 20px;
  display: flex; align-items: center; justify-content: space-between; gap: 12px;
}
.brand { font-weight: 700; letter-spacing: .2px; font-size: .98rem; }
.brand a { color: var(--ink); }
.brand .dot { color: var(--accent); }
.topbar .links { display: flex; gap: 16px; align-items: center; font-size: .85rem; }
.topbar .links a { color: var(--muted); }
.menu-btn {
  display: none; background: var(--card); border: 1px solid var(--border);
  color: var(--ink); border-radius: 8px; padding: 7px 11px; font-size: .9rem; cursor: pointer;
}

/* ---------- layout: sidebar + main ---------- */
.shell { max-width: 1180px; margin: 0 auto; display: flex; gap: 28px; padding: 0 20px; }
.sidebar {
  width: 250px; flex-shrink: 0; padding: 28px 0;
  position: sticky; top: 58px; align-self: flex-start; height: calc(100vh - 58px);
  overflow-y: auto;
}
.sidebar h4 { font-size: .72rem; text-transform: uppercase; letter-spacing: .12em;
  color: var(--faint); margin: 0 0 10px; }
.sidebar ol { list-style: none; margin: 0 0 26px; padding: 0; counter-reset: s; }
.sidebar ol li { counter-increment: s; margin: 2px 0; }
.sidebar ol a {
  display: flex; gap: 10px; align-items: baseline; padding: 8px 12px; border-radius: 9px;
  color: var(--muted); font-size: .9rem; border: 1px solid transparent;
}
.sidebar ol a::before { content: counter(s, decimal-leading-zero); color: var(--faint);
  font-family: var(--mono); font-size: .72rem; }
.sidebar ol a:hover { background: var(--card2); color: var(--ink); text-decoration: none; }
.sidebar ol a.active { background: linear-gradient(90deg, rgba(91,140,255,.14), transparent);
  border-color: var(--border2); color: var(--ink); }
.sidebar ol a.active::before { color: var(--accent); }

main { flex: 1; min-width: 0; padding: 34px 0 80px; max-width: var(--maxw); }

/* ---------- typography ---------- */
.eyebrow { color: var(--accent); font-family: var(--mono); font-size: .8rem;
  letter-spacing: .08em; text-transform: uppercase; margin: 0 0 10px; }
h1 { font-size: clamp(1.9rem, 4.5vw, 2.7rem); line-height: 1.15; margin: 0 0 14px; letter-spacing: -.02em; }
h2 { font-size: 1.5rem; margin: 46px 0 14px; letter-spacing: -.01em; scroll-margin-top: 70px; }
h3 { font-size: 1.15rem; margin: 28px 0 10px; }
.lead { font-size: 1.12rem; color: var(--muted); margin: 0 0 8px; max-width: 62ch; }
p { margin: 0 0 14px; }
strong { color: #fff; }
ul, ol { padding-left: 1.2em; }
li { margin: 5px 0; }
mark { background: linear-gradient(180deg, transparent 60%, rgba(91,140,255,.35) 60%);
  color: inherit; padding: 0 2px; }

/* ---------- cards ---------- */
.card {
  background: linear-gradient(180deg, var(--card), var(--card2));
  border: 1px solid var(--border); border-radius: var(--radius);
  padding: 20px 22px; margin: 18px 0;
}
.grid { display: grid; gap: 16px; }
.grid.cols-2 { grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); }
.grid.cols-3 { grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); }
.mini { background: var(--card2); border: 1px solid var(--border); border-radius: var(--radius-sm);
  padding: 16px 18px; }
.mini h3 { margin: 0 0 6px; font-size: 1rem; }
.mini p { margin: 0; color: var(--muted); font-size: .9rem; }
.tag { display: inline-block; font-family: var(--mono); font-size: .72rem;
  padding: 3px 9px; border-radius: 999px; border: 1px solid var(--border2);
  color: var(--muted); background: var(--card2); }

/* callouts */
.callout { border-left: 3px solid var(--accent); background: rgba(91,140,255,.07);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0; padding: 14px 18px; margin: 18px 0; }
.callout.warn { border-color: var(--c-augment); background: rgba(240,115,110,.08); }
.callout.tip { border-color: var(--c-generate); background: rgba(110,231,168,.08); }
.callout .k { font-weight: 700; color: #fff; }

/* ---------- code ---------- */
.code-wrap { position: relative; margin: 18px 0; }
.code-wrap .copy {
  position: absolute; top: 10px; right: 10px; z-index: 2;
  background: var(--card); border: 1px solid var(--border2); color: var(--muted);
  border-radius: 7px; padding: 5px 10px; font-size: .74rem; cursor: pointer; font-family: var(--mono);
}
.code-wrap .copy:hover { color: var(--ink); border-color: var(--accent); }
pre[class*="language-"] { border-radius: var(--radius-sm) !important; border: 1px solid var(--border);
  margin: 0 !important; font-size: .84rem; }
code:not([class*="language-"]) { background: #1b2440; border: 1px solid var(--border);
  padding: 1px 6px; border-radius: 5px; font-family: var(--mono); font-size: .85em; color: #cdd9ff; }

/* ---------- reveal animation ---------- */
.reveal { opacity: 0; transform: translateY(16px); transition: .6s cubic-bezier(.2,.7,.2,1); }
.reveal.show { opacity: 1; transform: none; }

/* ---------- prev/next ---------- */
.pager { display: flex; gap: 14px; margin-top: 50px; }
.pager a { flex: 1; border: 1px solid var(--border); border-radius: var(--radius);
  padding: 16px 18px; background: var(--card2); color: var(--ink); }
.pager a:hover { border-color: var(--accent); text-decoration: none; }
.pager .dir { font-size: .74rem; color: var(--faint); font-family: var(--mono); }
.pager .ttl { font-weight: 600; margin-top: 2px; }
.pager .next { text-align: right; }

/* ---------- pipeline diagram ---------- */
.pipeline { display: flex; flex-wrap: wrap; align-items: stretch; gap: 10px; margin: 8px 0; }
.pnode {
  flex: 1 1 130px; min-width: 120px; border: 1px solid var(--border2); border-radius: 12px;
  padding: 14px 12px; background: var(--card2); text-align: center;
  opacity: .28; transform: translateY(8px) scale(.98); transition: .45s cubic-bezier(.2,.7,.2,1);
}
.pnode.on { opacity: 1; transform: none; box-shadow: 0 0 0 1px var(--nc, var(--accent)), 0 8px 24px rgba(0,0,0,.3); }
.pnode .ico { font-size: 1.5rem; }
.pnode .nm { font-weight: 700; font-size: .9rem; margin-top: 4px; }
.pnode .sub { font-size: .74rem; color: var(--muted); }
.pnode[data-c="ingest"]  { --nc: var(--c-ingest); }
.pnode[data-c="embed"]   { --nc: var(--c-embed); }
.pnode[data-c="store"]   { --nc: var(--c-store); }
.pnode[data-c="retrieve"]{ --nc: var(--c-retrieve); }
.pnode[data-c="augment"] { --nc: var(--c-augment); }
.pnode[data-c="generate"]{ --nc: var(--c-generate); }
.pnode.on .nm { color: var(--nc); }
.btn {
  display: inline-flex; align-items: center; gap: 8px; cursor: pointer;
  background: linear-gradient(90deg, var(--accent), var(--accent2)); color: #fff;
  border: 0; border-radius: 10px; padding: 10px 18px; font-weight: 600; font-size: .9rem;
  font-family: var(--sans);
}
.btn:hover { opacity: .92; }
.btn.ghost { background: var(--card2); border: 1px solid var(--border2); color: var(--ink); }

/* ---------- tabs ---------- */
.tabs { display: flex; gap: 8px; flex-wrap: wrap; margin: 18px 0 0; }
.tab { background: var(--card2); border: 1px solid var(--border); color: var(--muted);
  border-radius: 999px; padding: 8px 16px; cursor: pointer; font-size: .88rem; font-family: var(--sans); }
.tab.active { color: #fff; border-color: var(--accent); background: rgba(91,140,255,.14); }
.tabpanel { display: none; }
.tabpanel.active { display: block; }

/* ---------- range / interactive ---------- */
input[type="range"] { width: 100%; accent-color: var(--accent); }
.chunks { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 12px; }
.chunk { padding: 6px 9px; border-radius: 7px; font-size: .82rem; line-height: 1.4;
  border: 1px solid var(--border2); }
.chunk:nth-child(5n+1){ background: rgba(240,163,94,.14); }
.chunk:nth-child(5n+2){ background: rgba(86,194,184,.14); }
.chunk:nth-child(5n+3){ background: rgba(157,123,255,.14); }
.chunk:nth-child(5n+4){ background: rgba(91,140,255,.14); }
.chunk:nth-child(5n+5){ background: rgba(110,231,168,.14); }

/* ranked list */
.ranklist { list-style: none; padding: 0; margin: 10px 0; }
.ranklist li { display: flex; align-items: center; gap: 10px; padding: 9px 12px; margin: 6px 0;
  border: 1px solid var(--border); border-radius: 9px; background: var(--card2);
  transition: .5s cubic-bezier(.2,.7,.2,1); }
.ranklist .score { font-family: var(--mono); font-size: .78rem; color: var(--accent);
  min-width: 46px; }
.ranklist .bar { height: 6px; border-radius: 4px; background: linear-gradient(90deg, var(--accent), var(--accent2)); }

/* comparison table */
.tablewrap { overflow-x: auto; margin: 18px 0; }
table { border-collapse: collapse; width: 100%; font-size: .9rem; }
th, td { border: 1px solid var(--border); padding: 10px 12px; text-align: left; }
th { background: var(--card2); color: #fff; }
td { color: var(--muted); }

/* footer */
.dd-footer { border-top: 1px solid var(--border); color: var(--faint);
  text-align: center; padding: 30px 20px; font-size: .82rem; }

/* ---------- responsive ---------- */
@media (max-width: 860px) {
  .shell { display: block; padding: 0 16px; }
  .menu-btn { display: inline-block; }
  .sidebar {
    position: fixed; inset: 58px auto 0 0; width: 280px; height: calc(100vh - 58px);
    background: var(--bg2); border-right: 1px solid var(--border); z-index: 40;
    padding: 22px 18px; transform: translateX(-105%); transition: transform .25s ease;
  }
  .sidebar.open { transform: none; box-shadow: var(--shadow); }
  main { padding-top: 24px; }
  .topbar .links .hide-sm { display: none; }
}