:root {
  --bg: #f1f5f9;
  --ink: #0f172a;
  --muted: #64748b;
  --line: #e2e8f0;
  /* the two models, one colour each — used everywhere their work appears */
  --enc: #0d9488;   /* the embedding model: retrieval + the index */
  --llm: #7c3aed;   /* the language model: generation */
  --index: #0f766e; /* the index is the embedding model's work too */
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}
* { box-sizing: border-box; }
html, body { margin: 0; min-height: 100%; }
body { color: var(--ink); background: var(--bg); }

/* --- back link ----------------------------------------------------------- */
.back {
  position: absolute; top: 12px; right: 16px; z-index: 10;
  font-size: 13px; font-weight: 600; color: var(--ink); text-decoration: none;
  background: rgba(255, 255, 255, 0.8); padding: 5px 10px; border-radius: 999px;
  border: 1px solid var(--line);
}
.back:hover { background: #fff; }

.wrap { max-width: 1080px; margin: 0 auto; padding: 30px 22px 48px; }

/* --- header -------------------------------------------------------------- */
.head { margin-bottom: 22px; }
/* The title and the demo button share a row. The button sits beside the title
   rather than out at the right edge, where the back link already is. */
.head-top { display: flex; align-items: center; flex-wrap: wrap; gap: 14px; margin: 0 0 8px; }
.head h1 { margin: 0; font-size: 30px; } /* .head-top carries the gap below */

/* Plays the whole pipeline on the first question, for a reader who would
   rather watch than choose. Both models run, so it borrows neither colour. */
.demo {
  background: var(--ink); color: #fff; border: none; border-radius: 999px; cursor: pointer;
  font-family: inherit; font-size: 13.5px; font-weight: 700; padding: 9px 16px;
  box-shadow: 0 6px 16px rgba(15, 23, 42, 0.22);
  transition: background 0.15s, box-shadow 0.15s;
}
.demo:hover:not(:disabled) { background: #1e293b; box-shadow: 0 8px 20px rgba(15, 23, 42, 0.3); }
.demo:disabled { background: #cbd5e1; color: #475569; cursor: default; box-shadow: none; }
.lede { font-size: 15px; line-height: 1.6; color: #334155; max-width: 760px; margin: 0; }
.lede strong { color: var(--ink); }

/* the steps, side by side, before any machinery is shown: the index that was
   built ahead of time, then the two models */
.two-models { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; margin: 20px 0 4px; }
.model {
  background: #fff; border: 1px solid var(--line); border-left: 4px solid var(--c);
  border-radius: 12px; padding: 13px 16px;
  box-shadow: 0 6px 20px rgba(15, 23, 42, 0.05);
}
.model-idx { --c: var(--index); }
.model-enc { --c: var(--enc); }
.model-llm { --c: var(--llm); }
.model-step {
  font-size: 10.5px; font-weight: 800; letter-spacing: 0.05em; text-transform: uppercase;
  color: var(--c);
}
.model-name { margin: 4px 0 6px; font-size: 18px; }
.model-blurb { margin: 0 0 9px; font-size: 13.5px; line-height: 1.55; color: #334155; }
.model-io {
  display: block; width: fit-content; max-width: 100%; white-space: nowrap; overflow-x: auto;
  font-size: 11.5px; padding: 3px 8px; border-radius: 6px;
  background: #f8fafc; border: 1px solid var(--line); color: var(--muted);
  font-family: "SF Mono", Menlo, Consolas, monospace;
}

/* --- asking -------------------------------------------------------------- */
/* The reader's own step, and it sits where it happens: after the index has been
   built, before retrieval has anything to go on. Slate rather than teal or
   violet — this is the one panel no model is doing the work in. */
.ask {
  background: #fff; border: 1px solid var(--line); border-top: 4px solid #94a3b8;
  border-radius: 14px; padding: 16px 18px; margin-top: 10px;
  box-shadow: 0 10px 28px rgba(15, 23, 42, 0.08);
}
.ask-head { display: flex; align-items: baseline; gap: 9px; flex-wrap: wrap; }
.ask-mark {
  width: 21px; height: 21px; border-radius: 999px; background: #475569; color: #fff;
  font-size: 12px; font-weight: 800; display: inline-flex; align-items: center;
  justify-content: center; align-self: center;
}
.ask-title { margin: 0; font-size: 17px; font-weight: 800; color: #334155; }
.ask-by {
  font-size: 11.5px; font-weight: 700; color: #475569;
  background: #f8fafc; border: 1px solid var(--line); border-radius: 999px; padding: 2px 9px;
}
.ask-sub {
  margin: 8px 0 12px; font-size: 12.5px; line-height: 1.55; color: var(--muted); max-width: 780px;
}
.chips { display: flex; flex-wrap: wrap; gap: 8px; margin: 8px 0 10px; }
.chip {
  background: #fff; border: 1px solid var(--line); border-radius: 999px;
  padding: 7px 13px; font-size: 13px; color: #334155; cursor: pointer;
  font-family: inherit; transition: border-color 0.15s, color 0.15s, box-shadow 0.15s;
}
.chip:hover:not(:disabled):not(.on) { border-color: var(--enc); color: var(--enc); }
.chip.on {
  border-color: var(--enc); color: #fff; background: var(--enc); font-weight: 600;
  box-shadow: 0 4px 12px rgba(13, 148, 136, 0.28);
}
.chip:disabled { cursor: default; opacity: 0.75; }
.chip.on:disabled { opacity: 1; } /* the question being answered stays legible */

.askbar { display: flex; gap: 8px; align-items: center; flex-wrap: wrap; }
.ask-input {
  flex: 1; min-width: 220px; max-width: 420px; font-family: inherit; font-size: 13.5px;
  padding: 9px 12px; border: 1px solid var(--line); border-radius: 10px; background: #fff;
  color: var(--ink);
}
.ask-input:focus { outline: 2px solid var(--enc); outline-offset: -1px; }
.run {
  background: var(--enc); color: #fff; border: none; cursor: pointer; font-family: inherit;
  font-size: 14px; font-weight: 700; padding: 10px 16px; border-radius: 10px;
  box-shadow: 0 6px 16px rgba(13, 148, 136, 0.28);
}
.run:disabled { background: #99f6e4; color: #0f766e; cursor: default; box-shadow: none; }
.reset {
  background: #fff; color: #334155; border: 1px solid var(--line); cursor: pointer;
  font-family: inherit; font-size: 13.5px; font-weight: 600; padding: 9px 14px; border-radius: 10px;
}
.reset:disabled { color: #cbd5e1; cursor: default; }

/* --- stages -------------------------------------------------------------- */
.flow {
  text-align: center; font-size: 20px; color: #cbd5e1; line-height: 1.1; margin: 3px 0;
  transition: color 0.5s;
}
.flow.on { color: var(--llm); }

/* Each panel is scrolled to as the run reaches it; this is the gap it keeps
   from the top of the window when it gets there. */
.ask, .stage { scroll-margin-top: 18px; }

.stage {
  background: #fff; border: 1px solid var(--line); border-top: 4px solid #cbd5e1;
  border-radius: 14px; padding: 16px 18px; opacity: 0.62;
  box-shadow: 0 6px 20px rgba(15, 23, 42, 0.05);
  transition: opacity 0.5s, box-shadow 0.5s;
}
.stage.reached { opacity: 1; box-shadow: 0 10px 28px rgba(15, 23, 42, 0.08); }
.stage.active { box-shadow: 0 0 0 3px var(--c), 0 14px 30px rgba(15, 23, 42, 0.12); }
.stage-index { --c: var(--index); border-top-color: var(--index); }
.stage-retrieve { --c: var(--enc); border-top-color: var(--enc); }
.stage-generate { --c: var(--llm); border-top-color: var(--llm); }

.stage-head { display: flex; align-items: baseline; gap: 9px; flex-wrap: wrap; }
.stage-num {
  width: 21px; height: 21px; border-radius: 999px; background: var(--c); color: #fff;
  font-size: 12px; font-weight: 800; display: inline-flex; align-items: center;
  justify-content: center; align-self: center;
}
.stage-name { font-size: 17px; font-weight: 800; color: var(--c); }
.stage-by {
  font-size: 11.5px; font-weight: 700; color: var(--c); background: color-mix(in srgb, var(--c) 10%, #fff);
  border: 1px solid color-mix(in srgb, var(--c) 25%, #fff); border-radius: 999px; padding: 2px 9px;
}
.stage-badge {
  margin-left: auto; font-size: 11px; font-weight: 700; color: #475569; background: #f1f5f9;
  border-radius: 999px; padding: 2px 9px; white-space: nowrap;
}
.stage-sub { margin: 8px 0 14px; font-size: 12.5px; line-height: 1.55; color: var(--muted); max-width: 780px; }

.stage-empty {
  display: flex; align-items: center; justify-content: center; gap: 9px; min-height: 96px;
  color: #94a3b8; font-size: 13px;
  border: 1.5px dashed #e2e8f0; border-radius: 10px; background: #fbfcfe;
}
.stage-empty-dot {
  width: 8px; height: 8px; border-radius: 999px; background: #cbd5e1;
  animation: pulse 1.4s ease-in-out infinite;
}
@keyframes pulse {
  0%, 100% { opacity: 0.35; transform: scale(0.8); }
  50% { opacity: 1; transform: scale(1.1); }
}

.split { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1.15fr); gap: 20px; }
.pane-title {
  margin: 0 0 10px; font-size: 12px; font-weight: 800; text-transform: uppercase;
  letter-spacing: 0.04em; color: var(--muted);
}
.pane-note { margin: 10px 0 0; font-size: 11.5px; line-height: 1.5; color: #94a3b8; }

/* --- vectors: what the encoder returns, written out ---------------------- */
.vec { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.vec-bracket {
  font-size: 26px; line-height: 0.95; color: #cbd5e1; font-weight: 300;
  font-family: "SF Mono", Menlo, Consolas, monospace;
}
.vec-num {
  font-size: 15px; font-weight: 700; color: #cbd5e1;
  font-family: "SF Mono", Menlo, Consolas, monospace;
}
.vec-num.on { color: var(--enc); }

/* --- stage 0: the index -------------------------------------------------- */
.why {
  margin: 0 0 12px; font-size: 12.5px; line-height: 1.6; color: #334155;
  background: #f0fdfa; border: 1px solid #ccfbf1; border-radius: 10px; padding: 9px 12px;
  max-width: 860px;
}
.why strong { color: var(--index); }

.chunks { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 10px; }
.chunk {
  border: 1px solid var(--line); border-radius: 10px; padding: 9px 10px; background: #fbfefe;
  display: flex; flex-direction: column; gap: 9px; justify-content: space-between;
  transition: border-color 0.2s, box-shadow 0.2s, background 0.2s;
}
.chunk.hi {
  border-color: var(--enc); background: #f0fdfa;
  box-shadow: 0 0 0 2px var(--enc), 0 8px 18px rgba(13, 148, 136, 0.15);
}
.chunk-text { min-width: 0; flex: 1; }
.chunk-title { display: block; font-size: 12px; font-weight: 800; color: var(--index); margin-bottom: 3px; }
/* In the index a chunk's vector is written out — it IS a list of numbers. */
.vecnum {
  display: block; font-size: 9.5px; line-height: 1.5; color: var(--index);
  font-family: "SF Mono", Menlo, Consolas, monospace; letter-spacing: -0.02em;
  white-space: nowrap; overflow-x: auto;
  background: #f0fdfa; border: 1px solid #ccfbf1; border-radius: 6px; padding: 4px 6px;
}
.chunk.hi .vecnum { background: #ccfbf1; }

.chunk-body {
  display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden;
  font-size: 10.5px; line-height: 1.45; color: var(--muted);
}

/* --- stage 1: retrieval -------------------------------------------------- */
.qtext { margin: 0 0 10px; font-size: 15px; font-weight: 600; color: var(--ink); line-height: 1.45; }
.words { margin: 0 0 12px; font-size: 11.5px; display: flex; flex-wrap: wrap; gap: 5px; align-items: center; }
.words-label { color: var(--muted); }
.w-hit {
  background: #ccfbf1; color: #0f766e; font-weight: 700; border-radius: 5px; padding: 2px 6px;
  font-family: "SF Mono", Menlo, Consolas, monospace;
}
.words-none { color: #b45309; background: #fffbeb; border-radius: 6px; padding: 5px 8px; line-height: 1.5; }

.ranks { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 4px; }
.rank {
  display: grid; grid-template-columns: 128px 1fr 34px 74px; align-items: center; gap: 8px;
  font-size: 11.5px; padding: 4px 6px; border-radius: 7px; border: 1px solid transparent;
  opacity: 0.45; transition: opacity 0.45s, background 0.45s, border-color 0.45s;
}
.rank.shown { opacity: 1; }
.rank.cut { opacity: 0.4; }
.rank.top { background: #f8fafc; border-color: var(--line); }
.rank.used { background: #f0fdfa; border-color: var(--enc); }
.rank.hi { border-color: var(--enc); background: #f0fdfa; opacity: 1; }
.rank-title { font-weight: 600; color: #334155; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.rank-track { height: 8px; background: #f1f5f9; border-radius: 999px; overflow: hidden; }
.rank-track i { display: block; height: 100%; background: #99f6e4; border-radius: 999px; transition: width 0.7s ease-out; }
.rank.used .rank-track i { background: var(--enc); }
.rank-score { font-family: "SF Mono", Menlo, Consolas, monospace; color: var(--muted); text-align: right; }
.rank-flag { font-size: 10px; font-weight: 700; color: var(--muted); text-align: right; }
.rank.used .rank-flag { color: var(--enc); }

/* --- stage 2: generation ------------------------------------------------- */
.prompt {
  background: #1e1b2e; border-radius: 10px; padding: 11px 12px; min-height: 84px;
  display: flex; flex-direction: column; gap: 7px;
}
.p-line {
  font-size: 11.5px; line-height: 1.5; color: #cbd5e1; border-radius: 6px; padding: 6px 8px;
  font-family: "SF Mono", Menlo, Consolas, monospace; animation: fade 0.5s ease-out;
  border: 1px solid transparent;
}
.p-sys { color: #a5b4fc; background: rgba(165, 180, 252, 0.1); }
.p-ctx { color: #5eead4; background: rgba(94, 234, 212, 0.1); }
.p-ctx.hi { border-color: #5eead4; background: rgba(94, 234, 212, 0.22); }
.p-empty { color: #fca5a5; background: rgba(252, 165, 165, 0.1); font-style: italic; }
.p-q { color: #fff; background: rgba(255, 255, 255, 0.12); font-weight: 600; }
@keyframes fade { from { opacity: 0; transform: translateY(-4px); } to { opacity: 1; transform: none; } }

.answer {
  border: 1px solid var(--line); border-left: 3px solid var(--llm); border-radius: 10px;
  padding: 11px 13px; background: #fdfbff; min-height: 84px;
}
.a-lead { margin: 0 0 7px; font-size: 12px; font-weight: 700; color: var(--llm); }
.a-line {
  margin: 0 0 7px; font-size: 13px; line-height: 1.55; color: #1e293b;
  border-radius: 6px; padding: 3px 5px; border: 1px solid transparent; animation: fade 0.55s ease-out;
}
.a-line.hi { border-color: var(--llm); background: #f5f3ff; }
.a-refuse { margin: 0; font-size: 13px; line-height: 1.55; color: #b45309; animation: fade 0.55s ease-out; }
.a-wait { margin: 0; color: #cbd5e1; font-size: 18px; letter-spacing: 3px; }
.cite {
  font-size: 10px; font-weight: 800; color: var(--llm); background: #ede9fe;
  border-radius: 4px; padding: 1px 4px; vertical-align: 1px;
}
.p-ctx .cite { color: #1e1b2e; background: #5eead4; }

.staged {
  margin: 10px 0 0; font-size: 11.5px; line-height: 1.55; color: #475569;
  background: #f8fafc; border: 1px solid var(--line); border-left: 3px solid #94a3b8;
  border-radius: 8px; padding: 8px 10px;
}
.staged strong { color: var(--ink); }

/* --- the comparison ------------------------------------------------------ */
.compare {
  margin-top: 22px; background: #fff; border: 1px solid var(--line); border-radius: 14px;
  padding: 18px; box-shadow: 0 6px 20px rgba(15, 23, 42, 0.05);
}
.compare h2 { margin: 0 0 12px; font-size: 19px; }
.cmp { width: 100%; border-collapse: collapse; font-size: 13px; }
.cmp th, .cmp td { border-bottom: 1px solid #eef2f6; padding: 9px 10px; text-align: left; vertical-align: top; }
.cmp thead th { font-size: 13.5px; }
.cmp thead th span {
  display: block; font-size: 10px; font-weight: 700; text-transform: uppercase;
  letter-spacing: 0.05em; opacity: 0.75;
}
.cmp tbody th { font-weight: 700; color: var(--muted); font-size: 12px; width: 128px; }
.cmp .c-enc { color: #0f766e; }
.cmp .c-llm { color: #6d28d9; }
.cmp thead .c-enc { border-bottom: 2px solid var(--enc); }
.cmp thead .c-llm { border-bottom: 2px solid var(--llm); }
.compare-note { margin: 12px 0 0; font-size: 12.5px; line-height: 1.6; color: #334155; }

/* --- narrower screens ---------------------------------------------------- */
@media (max-width: 900px) {
  .two-models { grid-template-columns: 1fr; }
  .chunks { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .split { grid-template-columns: 1fr; }
}
@media (max-width: 640px) {
  /* Here the header's demo button can reach the right edge, where the floating
     back link would sit on top of it. The link takes a row of its own instead,
     which also gives the title the breathing room above it that it had when the
     link was out of the flow. */
  .back { position: static; display: block; width: fit-content; margin: 14px 22px 0 auto; }
  .wrap { padding-top: 14px; }
  .two-models { grid-template-columns: 1fr; }
  .chunks { grid-template-columns: 1fr; }
  .rank { grid-template-columns: 100px 1fr 32px; }
  .rank-flag { display: none; }
}