:root {
  color-scheme: light dark;
  --bg: #0f1419;
  --surface: #1a2332;
  --surface-2: #243047;
  --text: #e7eef7;
  --muted: #94a3b8;
  --accent: #38bdf8;
  --accent-dim: #0ea5e9;
  --user-bg: #14532d;
  --user-border: #22c55e;
  --bot-bg: #1e3a5f;
  --bot-border: #38bdf8;
  --danger-bg: #450a0a;
  --danger-border: #f87171;
  --radius: 12px;
  --font: ui-sans-serif, system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
}

@media (prefers-color-scheme: light) {
  :root {
    --bg: #f4f6f9;
    --surface: #ffffff;
    --surface-2: #e8eef5;
    --text: #0f172a;
    --muted: #64748b;
    --user-bg: #dcfce7;
    --user-border: #16a34a;
    --bot-bg: #e0f2fe;
    --bot-border: #0284c7;
    --danger-bg: #fef2f2;
    --danger-border: #dc2626;
  }
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
}

.app {
  max-width: 720px;
  margin: 0 auto;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  padding: 1.25rem 1rem 1rem;
}

.header {
  margin-bottom: 1rem;
}

.header h1 {
  font-size: 1.35rem;
  font-weight: 700;
  margin: 0 0 0.25rem;
  letter-spacing: -0.02em;
}

.tagline {
  margin: 0;
  font-size: 0.875rem;
  color: var(--muted);
}

.main {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  min-height: 0;
}

.banner {
  padding: 0.65rem 0.85rem;
  border-radius: var(--radius);
  font-size: 0.875rem;
  border: 1px solid var(--danger-border);
  background: var(--danger-bg);
  color: var(--text);
}

.banner--hidden {
  display: none;
}

.transcript {
  flex: 1;
  overflow-y: auto;
  padding: 0.5rem 0;
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
  min-height: 200px;
}

.transcript--empty {
  justify-content: center;
  align-items: center;
  color: var(--muted);
  font-size: 0.9rem;
}

.msg {
  max-width: 92%;
  padding: 0.65rem 0.9rem;
  border-radius: var(--radius);
  border: 1px solid transparent;
  font-size: 0.9375rem;
}

.msg__meta {
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--muted);
  margin-bottom: 0.35rem;
  font-weight: 600;
}

.msg__text {
  white-space: pre-wrap;
  word-break: break-word;
}

.msg--user {
  align-self: flex-end;
  background: var(--user-bg);
  border-color: var(--user-border);
}

.msg--bot {
  align-self: flex-start;
  background: var(--bot-bg);
  border-color: var(--bot-border);
}

.msg--note {
  align-self: center;
  max-width: 100%;
  text-align: center;
  font-size: 0.8125rem;
  color: var(--muted);
  border: 1px dashed var(--muted);
  background: transparent;
}

.composer {
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
  padding-top: 0.25rem;
  border-top: 1px solid var(--surface-2);
}

.composer__input {
  width: 100%;
  resize: vertical;
  min-height: 2.75rem;
  padding: 0.6rem 0.75rem;
  border-radius: var(--radius);
  border: 1px solid var(--surface-2);
  background: var(--surface);
  color: var(--text);
  font: inherit;
}

.composer__input:focus {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

.composer__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.btn {
  font: inherit;
  font-size: 0.875rem;
  font-weight: 600;
  padding: 0.5rem 1rem;
  border-radius: 10px;
  border: none;
  cursor: pointer;
}

.btn:disabled {
  opacity: 0.55;
  cursor: not-allowed;
}

.btn--primary {
  background: var(--accent-dim);
  color: #fff;
}

.btn--primary:hover:not(:disabled) {
  filter: brightness(1.08);
}

.btn--ghost {
  background: var(--surface-2);
  color: var(--text);
}

.btn--ghost:hover:not(:disabled) {
  filter: brightness(1.06);
}

.footer {
  margin-top: 0.75rem;
  padding-top: 0.5rem;
  font-size: 0.75rem;
  color: var(--muted);
}

.session-label {
  word-break: break-all;
}

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