:root {
  --ink: #1c1f23;
  --muted: #646a72;
  --faint: #8b9098;
  --rule: #d9d3c5;
  --desk: #ebe7dc;
  --column: #f5f2ea;
  --paper: #fcfaf5;
  --accent: #9b2c24;
  --accent-soft: #f3e3df;
  --mark: #ffe17a;
  --ok: #2e6a3e;
  --sans: 'IBM Plex Sans', system-ui, sans-serif;
  --mono: 'IBM Plex Mono', ui-monospace, monospace;
  --serif: 'Source Serif 4', Georgia, serif;
}

* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  background: var(--desk);
  color: var(--ink);
  font: 15px/1.55 var(--sans);
  display: flex;
  flex-direction: column;
}
button { font: inherit; color: inherit; }
.visually-hidden { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }

/* Top bar */
.bar {
  display: flex; align-items: center; justify-content: space-between;
  padding: 10px 20px; border-bottom: 1px solid var(--rule); background: var(--column);
}
.brand { display: flex; align-items: center; gap: 12px; }
.brand h1 { margin: 0; font: 600 17px/1.2 var(--sans); letter-spacing: -0.01em; }
.brand p { margin: 0; font: 12px/1.3 var(--mono); color: var(--muted); }
.seal {
  width: 30px; height: 30px; display: grid; place-items: center;
  border: 1.5px solid var(--accent); border-radius: 50%; color: var(--accent);
  font: 600 14px/1 var(--serif); outline: 1px solid var(--accent); outline-offset: 2px;
}
.bar-actions { display: flex; gap: 18px; align-items: center; }
.link-button {
  background: none; border: 0; padding: 4px 0; cursor: pointer; color: var(--muted);
  border-bottom: 1px solid transparent; font-size: 14px;
}
.link-button:hover, .link-button:focus-visible { color: var(--ink); border-bottom-color: var(--ink); outline: none; }
.link-button.strong { color: var(--accent); font-weight: 600; }

/* Sign-in: a single sheet on the desk */
.gate { flex: 1; display: grid; place-items: center; padding: 32px 16px 64px; }
.gate[hidden] { display: none; }
body.gated .desk, body.gated #new-chat, body.gated #doc-toggle { display: none; }
.gate-card {
  width: min(400px, 100%); background: var(--paper); border: 1px solid var(--rule);
  box-shadow: 0 1px 0 var(--rule), 0 10px 24px -18px rgba(40, 32, 18, 0.35);
  padding: 30px 34px 26px;
}
.gate-card h2 { font: 400 27px/1.2 var(--serif); margin: 0 0 6px; }
.gate-lead { margin: 0 0 18px; color: var(--muted); font: 16px/1.5 var(--serif); }
.gate-card label { display: block; margin: 16px 0 6px; font: 500 11px/1 var(--mono); letter-spacing: 0.08em; text-transform: uppercase; color: var(--faint); }
.gate-card input {
  width: 100%; border: 1px solid var(--rule); border-radius: 2px; background: var(--column);
  padding: 10px 12px; font: 15px/1.4 var(--sans); color: var(--ink);
}
.gate-card input:focus { outline: none; border-color: var(--ink); background: var(--paper); }
.gate-card .send { width: 100%; margin-top: 22px; padding: 10px 16px; }
.gate-error { margin: 16px 0 0; padding: 6px 10px; border-left: 2px solid var(--accent); background: var(--accent-soft); font-size: 13.5px; }
.gate-note { margin: 18px 0 0; font-size: 12.5px; color: var(--faint); }
.gate-note a { color: var(--accent); }
.who { font: 12px/1.3 var(--mono); color: var(--muted); max-width: 26ch; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

/* Two-column desk */
.desk {
  flex: 1; min-height: 0;
  display: grid; grid-template-columns: minmax(360px, 1fr) minmax(400px, 1.05fr);
}
.chat {
  display: flex; flex-direction: column; min-height: 0;
  background: var(--column); border-right: 1px solid var(--rule);
}
.thread { flex: 1; overflow-y: auto; padding: 28px 28px 12px; scroll-behavior: smooth; }

.welcome h2 { font: 400 26px/1.25 var(--serif); margin: 8px 0 12px; max-width: 30ch; }
.welcome p { color: var(--muted); max-width: 52ch; margin: 0 0 22px; }
.examples { list-style: none; padding: 0; margin: 0; display: grid; gap: 2px; }
.example {
  background: none; border: 0; border-top: 1px solid var(--rule); padding: 11px 0; width: 100%;
  text-align: left; cursor: pointer; color: var(--ink);
}
.examples li:last-child .example { border-bottom: 1px solid var(--rule); }
.example::before { content: '→ '; color: var(--accent); font-family: var(--mono); }
.example:hover, .example:focus-visible { color: var(--accent); outline: none; }

/* Messages */
.question { margin: 4px 0 18px; padding-left: 12px; border-left: 2px solid var(--ink); }
.label { font: 500 11px/1 var(--mono); letter-spacing: 0.08em; text-transform: uppercase; color: var(--faint); margin-bottom: 6px; }
.question p { margin: 0; white-space: pre-wrap; }
.reply { margin: 0 0 30px; }

.steps { list-style: none; margin: 0 0 14px; padding: 0; font: 13px/1.5 var(--mono); }
.step { display: grid; grid-template-columns: 18px 1fr; gap: 6px; padding: 2px 0; color: var(--ink); }
.step .glyph { color: var(--faint); text-align: center; }
.step.done .glyph { color: var(--ok); }
.step.failed .glyph { color: var(--accent); }
.step.active .glyph { color: var(--accent); display: inline-block; animation: turn 1.1s linear infinite; }
.step.thinking.active .glyph { animation: pulse 1.2s ease-in-out infinite; }
.step .summary { color: var(--muted); }
.step .summary::before { content: ' — '; color: var(--faint); }
.step .timer { color: var(--faint); }
.step.note { color: var(--muted); font-style: italic; }
@keyframes turn { to { transform: rotate(360deg); } }
@keyframes pulse { 50% { opacity: 0.25; } }

.recap {
  background: none; border: 0; padding: 0; margin: 0 0 12px; cursor: pointer;
  font: 12px/1.4 var(--mono); color: var(--faint);
}
.recap:hover, .recap:focus-visible { color: var(--ink); outline: none; }
.steps.collapsed { display: none; }

/* Answer */
.answer { font-size: 15.5px; }
.answer:empty { display: none; }
.answer > :first-child { margin-top: 0; }
.answer h1, .answer h2, .answer h3, .answer h4 { font: 600 15px/1.35 var(--sans); margin: 18px 0 6px; }
.answer p, .answer ul, .answer ol { margin: 0 0 10px; }
.answer ul, .answer ol { padding-left: 20px; }
.answer li { margin: 3px 0; }
.answer a { color: var(--accent); text-decoration: underline; text-decoration-thickness: 1px; text-underline-offset: 2px; }
.answer a.doc-link { text-decoration-style: dotted; }
.answer strong { font-weight: 600; }
.answer blockquote { margin: 0 0 10px; padding: 2px 12px; border-left: 2px solid var(--rule); color: var(--muted); font-family: var(--serif); }
.answer code { font: 13px var(--mono); background: var(--accent-soft); padding: 0 4px; }
.answer table { border-collapse: collapse; margin: 6px 0 14px; font-size: 13.5px; width: 100%; }
.answer th, .answer td { border-bottom: 1px solid var(--rule); padding: 6px 8px 6px 0; text-align: left; vertical-align: top; }
.answer th { font-weight: 600; border-bottom-color: var(--ink); }
.answer.streaming::after { content: '▍'; color: var(--accent); animation: pulse 1s steps(2) infinite; }

.failure { border-left: 2px solid var(--accent); padding: 4px 12px; color: var(--ink); }
.failure button { margin-top: 6px; }

/* Composer */
.composer { border-top: 1px solid var(--rule); padding: 14px 28px 16px; background: var(--column); }
.composer textarea {
  width: 100%; resize: none; border: 1px solid var(--rule); background: var(--paper);
  padding: 11px 13px; font: 15px/1.5 var(--sans); color: var(--ink); max-height: 160px; border-radius: 2px;
}
.composer textarea:focus { outline: none; border-color: var(--ink); }
.composer-row { display: flex; justify-content: space-between; align-items: center; gap: 16px; margin-top: 8px; }
.hint { margin: 0; font-size: 12px; color: var(--faint); max-width: 48ch; }
.send {
  border: 1px solid var(--ink); background: var(--ink); color: var(--paper); padding: 7px 16px; cursor: pointer;
  font-weight: 500; border-radius: 2px; white-space: nowrap;
}
.send:hover, .send:focus-visible { background: var(--accent); border-color: var(--accent); outline: none; }
.send:disabled { background: transparent; color: var(--faint); border-color: var(--rule); cursor: wait; }
.turnstile:empty { display: none; }
.consent { border-left: 2px solid var(--ink); background: var(--paper); padding: 10px 12px; margin-bottom: 10px; font-size: 13.5px; }
.consent p { margin: 0 0 8px; }
.consent a, .hint a { color: var(--accent); }

/* Privacy notice page */
.notice-page { display: block; padding: 32px 16px 60px; }
.notice { max-width: 720px; margin: 0 auto; background: var(--paper); border: 1px solid var(--rule); padding: 36px 40px 40px; }
.notice h1 { font: 600 24px/1.3 var(--serif); margin: 0 0 6px; }
.notice h2 { font: 600 15px/1.4 var(--sans); margin: 24px 0 6px; }
.notice p, .notice li { font: 16px/1.6 var(--serif); }
.notice ul { padding-left: 20px; }
.notice .back a { color: var(--accent); font-family: var(--sans); }
.turnstile { margin-bottom: 10px; }
.pii { border-left: 2px solid var(--accent); background: var(--accent-soft); padding: 8px 12px; margin-bottom: 10px; font-size: 13.5px; }
.pii p { margin: 0 0 4px; }
.pii div { display: flex; gap: 16px; }

/* Document sheet */
.sheet-area { min-height: 0; display: flex; flex-direction: column; padding: 18px 26px 22px; }
.tabs { display: flex; gap: 6px; flex-wrap: wrap; margin-bottom: 10px; min-height: 26px; }
.tab {
  border: 1px solid var(--rule); background: transparent; padding: 3px 10px; cursor: pointer;
  font: 12px/1.4 var(--mono); color: var(--muted); max-width: 260px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.tab[aria-current='true'] { background: var(--paper); color: var(--ink); border-color: var(--ink); }
.tab:hover, .tab:focus-visible { color: var(--ink); outline: none; }
.sheet {
  flex: 1; overflow-y: auto; background: var(--paper); border: 1px solid var(--rule);
  box-shadow: 0 1px 0 var(--rule), 0 10px 24px -18px rgba(40, 32, 18, 0.35);
  padding: 34px 40px 40px;
}
.sheet-empty { color: var(--muted); max-width: 40ch; margin-top: 40px; font-family: var(--serif); font-size: 17px; }
.stamp {
  display: inline-block; margin: 0 0 14px; padding: 3px 9px 2px; border: 1.5px solid var(--accent); color: var(--accent);
  font: 600 11px/1.3 var(--mono); letter-spacing: 0.14em; transform: rotate(-1.5deg);
}
.stamp.muted { border-color: var(--faint); color: var(--faint); }
.sheet h2 { font: 600 22px/1.3 var(--serif); margin: 0 0 8px; }
.meta { font: 12.5px/1.5 var(--mono); color: var(--muted); margin: 0 0 22px; }
.meta a { color: var(--accent); white-space: nowrap; }
.passage { margin: 0 0 26px; }
.passage .label { margin-bottom: 8px; }
.passage p { font: 17px/1.65 var(--serif); margin: 0 0 12px; white-space: pre-wrap; }
mark { background: linear-gradient(transparent 12%, var(--mark) 12%, var(--mark) 88%, transparent 88%); color: inherit; padding: 0 1px; }

@media (max-width: 900px) {
  .desk { grid-template-columns: 1fr; }
  .chat { border-right: 0; }
  .thread, .composer { padding-left: 16px; padding-right: 16px; }
  .sheet-area { display: none; position: fixed; inset: 52px 0 0; background: var(--desk); padding: 12px 16px; z-index: 5; }
  .sheet-area.open { display: flex; }
  .sheet { padding: 22px 20px; }
  .doc-toggle:not([hidden]) { display: inline; }
  .hint { display: none; }
  .bar { padding: 10px 16px; }
  .brand p { display: none; }
  .who { display: none; }
  .gate { place-items: start center; padding-top: 24px; }
  .gate-card { padding: 24px 20px 20px; }
  .bar-actions { gap: 14px; }
  .link-button { white-space: nowrap; }
}
@media (min-width: 901px) { .doc-toggle { display: none; } }
@media (prefers-reduced-motion: reduce) {
  .step.active .glyph, .step.thinking.active .glyph, .answer.streaming::after { animation: none; }
}