/* Dark-first, Perplexity-inspired. System fonts only, so the page renders instantly. */

:root {
  --bg: #0b0d10;
  --bg-raise: #12151a;
  --surface: #161a20;
  --surface-hover: #1c2129;
  --border: #252b34;
  --border-strong: #333b47;
  --text: #e9edf2;
  --text-soft: #b4bcc8;
  --muted: #7d8794;
  --accent: #22d3ee;
  --accent-2: #6366f1;
  --accent-ink: #061318;
  --accent-soft: rgba(34, 211, 238, 0.12);
  --glow-a: rgba(34, 211, 238, 0.16);
  --glow-b: rgba(99, 102, 241, 0.14);
  --shadow: 0 10px 40px rgba(0, 0, 0, 0.45);
  --radius: 16px;
  --radius-lg: 22px;
  --sans: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  --composer-h: 0px;
  color-scheme: dark;
  font-family: var(--sans);
  -webkit-text-size-adjust: 100%;
}

@media (prefers-color-scheme: light) {
  :root {
    --bg: #f6f7f8;
    --bg-raise: #ffffff;
    --surface: #ffffff;
    --surface-hover: #f0f3f6;
    --border: #e2e6eb;
    --border-strong: #cfd5dc;
    --text: #12161c;
    --text-soft: #3b4450;
    --muted: #6b7480;
    --accent: #0891b2;
    --accent-2: #4f46e5;
    --accent-ink: #ffffff;
    --accent-soft: rgba(8, 145, 178, 0.1);
    --glow-a: rgba(8, 145, 178, 0.12);
    --glow-b: rgba(79, 70, 229, 0.09);
    --shadow: 0 10px 30px rgba(18, 22, 28, 0.08);
    color-scheme: light;
  }
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
html, body { margin: 0; }
body {
  min-height: 100vh;
  min-height: 100dvh;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
}
svg { width: 18px; height: 18px; fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; flex-shrink: 0; }
button { font: inherit; color: inherit; }

/* Ambient glow behind the hero; fades once a conversation starts. */
.glow {
  position: fixed;
  inset: -20vh -10vw auto;
  height: 70vh;
  background:
    radial-gradient(40% 50% at 35% 40%, var(--glow-a), transparent 70%),
    radial-gradient(35% 45% at 65% 35%, var(--glow-b), transparent 70%);
  filter: blur(20px);
  pointer-events: none;
  z-index: 0;
  transition: opacity 0.6s ease;
}
.is-thread .glow { opacity: 0.35; }

/* Top bar ---------------------------------------------------------------- */

.bar {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 14px max(16px, env(safe-area-inset-left));
  background: color-mix(in srgb, var(--bg) 78%, transparent);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid transparent;
  transition: border-color 0.3s;
}
.is-thread .bar { border-bottom-color: var(--border); }

.brand { display: flex; align-items: center; gap: 10px; background: none; border: 0; padding: 0; cursor: pointer; }
.mark {
  display: grid; place-items: center;
  width: 32px; height: 32px; border-radius: 9px;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: #fff; font-weight: 700; font-size: 13px; letter-spacing: 0.02em;
  box-shadow: 0 0 24px var(--glow-a);
}
.brand-name { font-weight: 600; font-size: 0.95rem; }

.bar-actions { display: flex; gap: 8px; align-items: center; }
.ghost, .cta {
  display: inline-flex; align-items: center; gap: 6px;
  height: 36px; padding: 0 14px; border-radius: 999px;
  font-size: 0.875rem; font-weight: 550; text-decoration: none; cursor: pointer;
  white-space: nowrap;
}
.ghost { background: transparent; border: 1px solid var(--border); color: var(--text-soft); }
.ghost:hover { background: var(--surface-hover); color: var(--text); }
.cta { background: var(--text); color: var(--bg); border: 0; }
.cta:hover { opacity: 0.9; }
.cta .li { width: 16px; height: 16px; }

/* Layout ------------------------------------------------------------------ */

.main {
  position: relative;
  z-index: 1;
  flex: 1;
  width: 100%;
  max-width: 780px;
  margin: 0 auto;
  padding: 0 16px;
  display: flex;
  flex-direction: column;
}
.is-landing .main { justify-content: center; padding-bottom: 6vh; }

/* Hero -------------------------------------------------------------------- */

.hero { text-align: center; padding: 6vh 0 28px; }
.is-thread .hero, .is-thread .starters { display: none; }

.eyebrow {
  display: inline-flex; align-items: center; gap: 8px;
  margin: 0 0 18px; padding: 6px 12px;
  border: 1px solid var(--border); border-radius: 999px;
  background: color-mix(in srgb, var(--surface) 70%, transparent);
  color: var(--text-soft); font-family: var(--mono); font-size: 0.72rem; letter-spacing: 0.02em;
}
.dot { width: 7px; height: 7px; border-radius: 50%; background: var(--accent); box-shadow: 0 0 10px var(--accent); }

h1 {
  margin: 0 0 10px;
  font-size: clamp(1.75rem, 4.6vw, 2.6rem);
  line-height: 1.15;
  letter-spacing: -0.025em;
  font-weight: 650;
  background: linear-gradient(180deg, var(--text) 30%, color-mix(in srgb, var(--text) 60%, var(--accent)));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.sub { margin: 0; color: var(--muted); font-size: 1rem; }

/* Composer ---------------------------------------------------------------- */

.composer {
  position: relative;
  background: var(--surface);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-lg);
  padding: 14px 14px 10px 18px;
  box-shadow: var(--shadow);
  transition: border-color 0.2s, box-shadow 0.2s;
}
.composer:focus-within {
  border-color: color-mix(in srgb, var(--accent) 55%, var(--border-strong));
  box-shadow: var(--shadow), 0 0 0 4px var(--accent-soft);
}
.is-thread .composer {
  position: sticky;
  bottom: max(14px, env(safe-area-inset-bottom));
  margin-top: auto;
  z-index: 10;
  /* Fade the thread out behind the docked composer instead of a hard edge. */
  box-shadow: var(--shadow), 0 26px 0 14px var(--bg), 0 -6px 30px 18px var(--bg);
}

textarea {
  display: block;
  width: 100%;
  min-height: 28px;
  max-height: 180px;
  resize: none;
  border: 0;
  outline: 0;
  background: transparent;
  color: var(--text);
  font: inherit;
  font-size: 16px; /* below 16px, iOS zooms on focus */
  line-height: 1.5;
  padding: 2px 0;
}
textarea::placeholder { color: var(--muted); }
textarea:focus-visible { outline: none; } /* the composer's focus ring covers it */
.is-landing textarea { min-height: 52px; }

.composer-row { display: flex; align-items: center; justify-content: flex-end; gap: 12px; margin-top: 6px; }
.count { font-family: var(--mono); font-size: 0.7rem; color: var(--muted); }
.count.over { color: #f87171; }

.send {
  display: grid; place-items: center;
  width: 36px; height: 36px; border-radius: 50%;
  border: 0; cursor: pointer;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: #fff;
  transition: transform 0.15s, opacity 0.2s;
}
.send:hover:not(:disabled) { transform: translateY(-1px); }
.send:disabled { opacity: 0.35; cursor: default; }
.send svg { stroke-width: 2.2; }

/* Starters ---------------------------------------------------------------- */

.starters {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  margin-top: 18px;
}
.starter {
  display: flex; align-items: flex-start; gap: 10px;
  text-align: left; cursor: pointer;
  padding: 12px 14px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: color-mix(in srgb, var(--surface) 75%, transparent);
  color: var(--text-soft);
  font-size: 0.9rem; line-height: 1.4;
  transition: border-color 0.2s, background 0.2s, color 0.2s, transform 0.2s;
}
.starter svg { color: var(--accent); margin-top: 1px; }
.starter:hover { border-color: var(--border-strong); background: var(--surface-hover); color: var(--text); transform: translateY(-1px); }

/* Thread ------------------------------------------------------------------ */

.thread { display: flex; flex-direction: column; }
.is-thread .thread { padding-top: 12px; }

.turn {
  padding: 22px 0 26px;
  border-bottom: 1px solid var(--border);
  animation: rise 0.35s ease both;
  scroll-margin-top: 76px;
}
.turn:last-child { border-bottom: 0; }

.q {
  margin: 0 0 18px;
  font-size: clamp(1.3rem, 3vw, 1.6rem);
  line-height: 1.3;
  letter-spacing: -0.015em;
  font-weight: 600;
  overflow-wrap: anywhere;
}

.label {
  display: flex; align-items: center; gap: 8px;
  margin: 0 0 10px;
  color: var(--text-soft);
  font-size: 0.8rem; font-weight: 600; letter-spacing: 0.04em; text-transform: uppercase;
}
.label svg { width: 16px; height: 16px; color: var(--accent); }

/* Source cards */
.sources { margin-bottom: 22px; }
.cards {
  display: flex; gap: 10px;
  overflow-x: auto;
  scroll-snap-type: x proximity;
  padding-bottom: 4px;
  scrollbar-width: thin;
}
.card {
  flex: 0 0 auto;
  width: 200px;
  min-height: 78px;
  scroll-snap-align: start;
  padding: 10px 12px;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: var(--surface);
  display: flex; flex-direction: column; gap: 4px;
}
.card-kicker {
  display: flex; align-items: center; gap: 6px;
  font-family: var(--mono); font-size: 0.68rem; color: var(--muted);
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.card-kicker .n {
  display: inline-grid; place-items: center;
  min-width: 16px; height: 16px; padding: 0 4px; border-radius: 5px;
  background: var(--accent-soft); color: var(--accent); font-size: 0.65rem; font-weight: 700;
}
.card-title {
  font-size: 0.83rem; line-height: 1.35; color: var(--text);
  display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden;
}

/* Answer */
.answer { font-size: 1rem; color: var(--text); }
.answer p { margin: 0 0 0.8em; }
.answer p:last-child { margin-bottom: 0; }
.answer ul, .answer ol { margin: 0 0 0.8em; padding-left: 1.3em; }
.answer li { margin: 0.25em 0; }
.answer li::marker { color: var(--accent); }
.answer strong { font-weight: 650; }
.answer a { color: var(--accent); text-underline-offset: 3px; }

.tools { display: flex; gap: 6px; margin-top: 14px; }
.tool {
  display: inline-flex; align-items: center; gap: 6px;
  height: 30px; padding: 0 10px; border-radius: 8px;
  border: 1px solid transparent; background: transparent; color: var(--muted);
  font-size: 0.8rem; cursor: pointer;
}
.tool svg { width: 15px; height: 15px; }
.tool:hover { background: var(--surface-hover); color: var(--text); }

/* Related questions */
.related { margin-top: 22px; }
.related-list { list-style: none; margin: 0; padding: 0; border-top: 1px solid var(--border); }
.related-list li { border-bottom: 1px solid var(--border); }
.related-btn {
  width: 100%;
  display: flex; align-items: center; justify-content: space-between; gap: 12px;
  padding: 11px 2px;
  background: none; border: 0; cursor: pointer; text-align: left;
  color: var(--text-soft); font-size: 0.95rem;
}
.related-btn svg { color: var(--accent); opacity: 0.7; transition: transform 0.2s; }
.related-btn:hover { color: var(--text); }
.related-btn:hover svg { transform: translateX(3px); opacity: 1; }

/* Loading state */
.skeleton { display: flex; gap: 10px; margin-bottom: 22px; }
.skeleton span {
  width: 200px; height: 78px; border-radius: 12px;
  background: linear-gradient(90deg, var(--surface) 0%, var(--surface-hover) 50%, var(--surface) 100%);
  background-size: 200% 100%;
  animation: shimmer 1.3s linear infinite;
}
.thinking { display: flex; align-items: center; gap: 10px; color: var(--muted); font-size: 0.95rem; }
.orb {
  width: 14px; height: 14px; border-radius: 50%;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  animation: pulse 1.1s ease-in-out infinite;
  box-shadow: 0 0 14px var(--glow-a);
}

@keyframes shimmer { to { background-position: -200% 0; } }
@keyframes pulse { 0%, 100% { transform: scale(0.75); opacity: 0.6; } 50% { transform: scale(1); opacity: 1; } }
@keyframes rise { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: none; } }

/* Footer ------------------------------------------------------------------ */

.notice {
  position: relative; z-index: 1;
  max-width: 780px; width: 100%;
  margin: 0 auto;
  padding: 14px 16px calc(14px + env(safe-area-inset-bottom));
  text-align: center;
  color: var(--muted);
  font-size: 0.74rem;
}
.is-thread .notice { padding-top: 6px; }
.credit { display: block; margin-top: 4px; }
.credit a { color: inherit; text-underline-offset: 2px; }

:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; border-radius: 6px; }
.visually-hidden { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
.noscript { text-align: center; padding: 16px; }

@media (max-width: 600px) {
  .brand-name { display: none; }
  .ghost { padding: 0 10px; }
  .cta { padding: 0 12px; }
  .br-wide { display: none; }
  .eyebrow-more { display: none; }
  .hero { padding-top: 3vh; }
  .starters { grid-template-columns: 1fr; }
  .card, .skeleton span { width: 168px; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition: none !important; }
}