:root {
  color-scheme: dark light;
  --bg: #0f1115;
  --panel: #171a21;
  --text: #e8eaef;
  --muted: #9aa3b2;
  --accent: #5b8cff;
  --border: #2a3140;
  font-family: system-ui, Segoe UI, Roboto, sans-serif;
}

@media (prefers-color-scheme: light) {
  :root {
    --bg: #f6f7fb;
    --panel: #fff;
    --text: #12151c;
    --muted: #5c6575;
    --border: #dfe3ec;
  }
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100dvh;
  background: var(--bg);
  color: var(--text);
}

.shell {
  max-width: 42rem;
  margin: 0 auto;
  padding: 1.25rem 1rem 2rem;
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
}

.head {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.head h1 {
  font-size: 1.35rem;
  font-weight: 650;
  margin: 0 0 0.35rem;
  color: #000;
}

.sub {
  margin: 0;
  color: var(--muted);
  font-size: 0.92rem;
  line-height: 1.45;
}

.sub a {
  color: var(--accent);
}

.log {
  flex: 1;
  margin-top: 1rem;
  padding: 0.75rem;
  background: var(--panel);
  border: 1px solid var(--accent);
  border-radius: 12px;
  overflow-y: auto;
  max-height: min(58dvh, 520px);
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.bubble {
  padding: 0.65rem 0.85rem;
  border-radius: 10px;
  font-size: 0.95rem;
  line-height: 1.5;
  white-space: pre-wrap;
}

.bubble.user {
  align-self: flex-end;
  background: color-mix(in oklab, var(--accent) 22%, transparent);
  border: 1px solid color-mix(in oklab, var(--accent) 45%, var(--border));
}

.bubble.bot {
  align-self: stretch;
  background: color-mix(in oklab, var(--panel) 88%, var(--bg));
  border: 1px solid var(--border);
}

.bubble.err {
  border-color: #c44;
  color: #f8b4b4;
}

.form {
  margin-top: 0.75rem;
  display: flex;
  gap: 0.5rem;
  align-items: flex-end;
}

textarea {
  flex: 1;
  resize: vertical;
  min-height: 2.75rem;
  padding: 0.6rem 0.75rem;
  border-radius: 10px;
  border: 1px solid var(--accent);
  background: var(--panel);
  color: var(--text);
  font: inherit;
}

button {
  padding: 0.55rem 1rem;
  border-radius: 10px;
  border: 1px solid color-mix(in oklab, var(--accent) 55%, var(--border));
  background: var(--accent);
  color: #fff;
  font-weight: 600;
  cursor: pointer;
}

button:disabled {
  opacity: 0.55;
  cursor: not-allowed;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}