/* ---------------------------------------------------------------------------
   Lighthouse Discovery — editorial theme
   Serif display (Newsreader) · mono labels (IBM Plex Mono) · navy rail / paper.
--------------------------------------------------------------------------- */
:root {
  --navy: #0b1220;
  --navy-2: #0e1728;
  --ink: #131722;
  --paper: #f6f7f9;
  --paper-2: #ffffff;
  --muted: #8a92a0;
  --muted-2: #5b6472;
  --line: #e5e8ec;
  --line-rail: rgba(255, 255, 255, 0.10);
  --blue: #3f5c80;        /* labels, numbers */
  --blue-bright: #5b7cae; /* dot / accents on navy */
  --rail-fg: #d7dde6;
  --rail-fg-dim: #8b93a2;

  --serif: "Newsreader", Georgia, "Times New Roman", serif;
  --mono: "IBM Plex Mono", ui-monospace, "SF Mono", Menlo, monospace;
  --sans: ui-sans-serif, -apple-system, "Segoe UI", Helvetica, Arial, sans-serif;
}

* { box-sizing: border-box; }

html, body { margin: 0; padding: 0; }

body {
  font-family: var(--sans);
  color: var(--ink);
  background: var(--paper);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

.hidden { display: none !important; }

.label {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--blue);
  font-weight: 500;
}
.muted { color: var(--muted); }

/* ---- Layout --------------------------------------------------------------- */
.layout {
  display: grid;
  grid-template-columns: minmax(300px, 27%) 1fr;
  min-height: 100vh;
}

/* ---- Left rail ------------------------------------------------------------ */
.rail {
  background: var(--navy);
  color: var(--rail-fg);
  padding: 44px 40px 32px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  position: sticky;
  top: 0;
  height: 100vh;
  overflow-y: auto;
}

.brand {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.28em;
  text-transform: uppercase;
  color: var(--rail-fg);
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 56px;
}
.brandbar {
  width: 2px;
  height: 26px;
  background: var(--blue-bright);
  display: inline-block;
}

.display {
  font-family: var(--serif);
  font-weight: 500;
  font-size: 42px;
  line-height: 1.06;
  letter-spacing: -0.01em;
  color: #f3f5f8;
  margin: 0 0 22px;
}
.display em { font-style: italic; font-weight: 400; }

.rail-sub {
  font-size: 15px;
  line-height: 1.55;
  color: var(--rail-fg-dim);
  max-width: 300px;
  margin: 0 0 52px;
}

.rail-section .label { color: var(--rail-fg-dim); }

.corpus { margin-top: 20px; }
.corpus-item {
  padding: 20px 0;
  border-top: 1px solid var(--line-rail);
}
.corpus-item:first-child { border-top: 1px solid var(--line-rail); }
.corpus-item .serif {
  font-family: var(--serif);
  font-size: 23px;
  font-weight: 500;
  color: #eef1f5;
  margin-bottom: 6px;
}
.corpus-item .muted { font-size: 13px; color: var(--rail-fg-dim); }

.rail-foot { color: var(--rail-fg-dim); margin-top: 40px; }

/* ---- Content -------------------------------------------------------------- */
.content {
  padding: 56px clamp(40px, 6vw, 96px) 40px;
  max-width: 1180px;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.eyebrow {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--muted-2);
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 30px;
}
.dot {
  width: 7px; height: 7px; border-radius: 50%;
  background: var(--blue-bright);
  display: inline-block;
}

.hero {
  font-family: var(--serif);
  font-weight: 500;
  font-size: clamp(40px, 5.4vw, 72px);
  line-height: 1.03;
  letter-spacing: -0.02em;
  margin: 0 0 26px;
  color: var(--ink);
}
.hero em { font-style: italic; font-weight: 400; }

.hero-sub {
  font-size: 18px;
  line-height: 1.6;
  color: var(--muted-2);
  max-width: 620px;
  margin: 0 0 40px;
}

/* ---- Ask box -------------------------------------------------------------- */
.ask {
  display: flex;
  gap: 0;
  align-items: stretch;
  border: 1px solid #d7dbe1;
  background: var(--paper-2);
  margin-bottom: 64px;
}
.ask input {
  flex: 1;
  border: 0;
  outline: none;
  padding: 22px 24px;
  font-family: var(--sans);
  font-size: 17px;
  color: var(--ink);
  background: transparent;
}
.ask input::placeholder { color: #9aa2ae; }
.ask button {
  width: 60px;
  border: 0;
  background: var(--navy);
  color: #fff;
  font-size: 20px;
  cursor: pointer;
  margin: 8px;
  transition: background 0.15s ease;
}
.ask button:hover { background: #17233a; }
.ask button:disabled { opacity: 0.5; cursor: default; }

/* ---- Section heads -------------------------------------------------------- */
.section-head {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin: 8px 0 20px;
}

/* ---- Pipeline ------------------------------------------------------------- */
.pipeline {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  border: 1px solid var(--line);
  background: var(--paper-2);
  margin-bottom: 56px;
}
.stage {
  padding: 26px 24px 30px;
  border-left: 1px solid var(--line);
}
.stage:first-child { border-left: 0; }
.stage .num {
  font-family: var(--serif);
  font-size: 18px;
  color: var(--blue);
  margin-bottom: 22px;
}
.stage-title {
  font-family: var(--serif);
  font-size: 23px;
  font-weight: 500;
  margin-bottom: 10px;
}
.stage .muted { font-size: 13px; }

/* ---- Examples ------------------------------------------------------------- */
.examples {
  border: 1px solid var(--line);
  background: var(--paper-2);
}
.example {
  display: grid;
  grid-template-columns: 170px 1fr 30px;
  align-items: center;
  gap: 24px;
  width: 100%;
  text-align: left;
  padding: 26px 28px;
  border: 0;
  border-top: 1px solid var(--line);
  background: transparent;
  cursor: pointer;
  transition: background 0.12s ease;
}
.example:first-child { border-top: 0; }
.example:hover { background: #f0f2f5; }
.ex-cat {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--blue);
}
.ex-main { display: flex; flex-direction: column; gap: 6px; }
.ex-main .serif { font-family: var(--serif); font-size: 24px; font-weight: 500; }
.ex-main .muted { font-size: 14px; }
.chev { font-size: 20px; color: #b6bdc7; text-align: right; }
.example:hover .chev { color: var(--blue); }

/* ---- Footer --------------------------------------------------------------- */
.content-foot {
  margin-top: auto;
  padding-top: 28px;
  border-top: 1px solid var(--line);
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.linkbtn {
  background: none;
  border: 0;
  cursor: pointer;
  color: var(--muted-2);
  padding: 0;
}
.linkbtn:hover { color: var(--ink); }

/* ---- Conversation thread -------------------------------------------------- */
.thread { margin-bottom: 40px; }
.qa { padding: 12px 0 40px; border-top: 1px solid var(--line); margin-top: 8px; }
.qa:first-child { border-top: 0; }
.qa-qlabel { margin-bottom: 12px; }
.qa-q {
  font-family: var(--serif);
  font-size: 30px;
  font-weight: 500;
  line-height: 1.2;
  letter-spacing: -0.01em;
  margin: 0 0 22px;
  color: var(--ink);
}
.qa-routed { margin-bottom: 18px; }
.qa-routed b { color: var(--blue); font-weight: 500; }

.answer {
  font-size: 17.5px;
  line-height: 1.72;
  color: #22272f;
  max-width: 760px;
}
.answer h1, .answer h2, .answer h3 {
  font-family: var(--serif);
  font-weight: 600;
  letter-spacing: -0.01em;
  line-height: 1.25;
  margin: 30px 0 12px;
}
.answer h1 { font-size: 26px; }
.answer h2 { font-size: 23px; }
.answer h3 { font-size: 19px; }
.answer p { margin: 0 0 16px; }
.answer ul, .answer ol { margin: 0 0 16px; padding-left: 22px; }
.answer li { margin-bottom: 6px; }
.answer strong { font-weight: 600; }
.answer table {
  border-collapse: collapse;
  width: 100%;
  margin: 8px 0 20px;
  font-size: 15px;
}
.answer th, .answer td {
  border: 1px solid var(--line);
  padding: 9px 12px;
  text-align: left;
  vertical-align: top;
}
.answer th { background: #eef1f4; font-weight: 600; }
.answer code {
  font-family: var(--mono);
  font-size: 0.88em;
  background: #eef1f4;
  padding: 1px 5px;
  border-radius: 3px;
}

/* citation chips: [S1] -> superscript pill */
.cite {
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.04em;
  color: var(--blue);
  border: 1px solid #c9d2df;
  border-radius: 3px;
  padding: 1px 4px;
  margin: 0 1px;
  vertical-align: super;
  line-height: 1;
  white-space: nowrap;
}

.cursor::after {
  content: "";
  display: inline-block;
  width: 8px; height: 1.05em;
  background: var(--blue);
  margin-left: 2px;
  vertical-align: text-bottom;
  animation: blink 1s steps(2, start) infinite;
}
@keyframes blink { to { visibility: hidden; } }

/* ---- Sources -------------------------------------------------------------- */
.sources { margin-top: 34px; }
.src {
  border: 1px solid var(--line);
  border-top: 0;
  background: var(--paper-2);
}
.src:first-of-type { border-top: 1px solid var(--line); }
.src summary {
  display: grid;
  grid-template-columns: 54px 1fr auto;
  gap: 18px;
  align-items: center;
  padding: 16px 20px;
  cursor: pointer;
  list-style: none;
}
.src summary::-webkit-details-marker { display: none; }
.src-tag {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--blue);
  font-weight: 500;
}
.src-title { font-family: var(--serif); font-size: 17px; }
.src-meta { font-family: var(--mono); font-size: 11px; color: var(--muted); letter-spacing: 0.04em; }
.src-body {
  padding: 4px 20px 20px 92px;
  font-size: 14px;
  line-height: 1.6;
  color: var(--muted-2);
  white-space: pre-wrap;
}

/* ---- Login overlay -------------------------------------------------------- */
.login {
  position: fixed; inset: 0; z-index: 50;
  background: var(--navy);
  display: flex; align-items: center; justify-content: center;
  padding: 24px;
}
.login-card { width: 100%; max-width: 420px; color: var(--rail-fg); }
.login-card .brand { margin-bottom: 40px; }
.login-title {
  font-family: var(--serif);
  font-weight: 500;
  font-size: 40px;
  line-height: 1.08;
  color: #f3f5f8;
  margin: 0 0 14px;
}
.login-title em { font-style: italic; font-weight: 400; }
.login-sub { color: var(--rail-fg-dim); font-size: 15px; margin: 0 0 28px; }
.login-form { display: flex; gap: 0; border: 1px solid var(--line-rail); }
.login-form input {
  flex: 1; border: 0; outline: none; background: transparent;
  color: #fff; padding: 16px 18px; font-size: 16px; font-family: var(--sans);
}
.login-form input::placeholder { color: #6b7484; }
.login-form button {
  border: 0; background: var(--blue-bright); color: #fff;
  padding: 0 22px; font-size: 15px; cursor: pointer;
  font-family: var(--mono); letter-spacing: 0.08em;
}
.login-form button:hover { background: #6c8cbd; }
.login-err { color: #e08b8b; font-size: 13px; min-height: 18px; margin: 14px 0 0; }

/* ---- Responsive ----------------------------------------------------------- */
@media (max-width: 900px) {
  .layout { grid-template-columns: 1fr; }
  .rail { position: static; height: auto; }
  .display { font-size: 34px; }
  .pipeline { grid-template-columns: repeat(2, 1fr); }
  .stage:nth-child(3) { border-left: 0; }
  .example { grid-template-columns: 1fr 24px; }
  .ex-cat { display: none; }
}