:root {
  color-scheme: dark;
  --bg: #0b1220;
  --bg-elevated: #121a2b;
  --bg-soft: #182235;
  --border: #2a3650;
  --text: #e8edf7;
  --muted: #9aa8c2;
  --accent: #4f8cff;
  --accent-strong: #2f6fed;
  --user: #1f3b67;
  --assistant: #152033;
  --success: #3ecf8e;
  --danger: #ff6b6b;
  --shadow: 0 18px 50px rgba(0, 0, 0, 0.28);
  --radius: 16px;
  --radius-sm: 10px;
  font-family: Inter, Segoe UI, system-ui, sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  background:
    radial-gradient(circle at top left, rgba(79, 140, 255, 0.18), transparent 28%),
    linear-gradient(180deg, #0a1020 0%, #0b1220 100%);
  color: var(--text);
}

button,
input,
select,
textarea {
  font: inherit;
}

.app {
  display: grid;
  grid-template-columns: 300px 1fr;
  min-height: 100vh;
}

.sidebar {
  padding: 24px;
  border-right: 1px solid var(--border);
  background: rgba(10, 16, 28, 0.92);
  backdrop-filter: blur(10px);
}

.brand {
  display: flex;
  gap: 14px;
  align-items: center;
  margin-bottom: 24px;
}

.brand-icon {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  display: grid;
  place-items: center;
  background: linear-gradient(135deg, var(--accent), #7cb7ff);
  color: #08111f;
  font-size: 1.2rem;
  font-weight: 700;
}

.brand h1,
.chat-header h2 {
  margin: 0;
  font-size: 1.2rem;
}

.brand p,
.chat-header p,
.hint,
.status {
  margin: 4px 0 0;
  color: var(--muted);
  font-size: 0.9rem;
}

.panel {
  display: grid;
  gap: 8px;
  margin-bottom: 18px;
}

.panel label,
.sources h2 {
  font-size: 0.82rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
}

.panel input,
.panel select,
.composer textarea {
  width: 100%;
  border: 1px solid var(--border);
  background: var(--bg-soft);
  color: var(--text);
  border-radius: var(--radius-sm);
  padding: 12px 14px;
}

.sources ul {
  margin: 10px 0 0;
  padding-left: 18px;
  color: var(--muted);
  line-height: 1.7;
}

.btn {
  border: 0;
  border-radius: var(--radius-sm);
  padding: 12px 16px;
  cursor: pointer;
  transition: transform 0.15s ease, background 0.15s ease, opacity 0.15s ease;
}

.btn:hover:not(:disabled) {
  transform: translateY(-1px);
}

.btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent-strong), var(--accent));
  color: white;
  min-width: 96px;
}

.btn-secondary {
  width: 100%;
  margin-bottom: 18px;
  background: var(--bg-soft);
  color: var(--text);
  border: 1px solid var(--border);
}

.chat {
  display: grid;
  grid-template-rows: auto 1fr auto;
  min-height: 100vh;
}

.chat-header {
  padding: 24px 28px 12px;
  border-bottom: 1px solid rgba(42, 54, 80, 0.65);
}

.messages {
  overflow-y: auto;
  padding: 24px 28px 12px;
}

.welcome h3 {
  margin: 0 0 14px;
  font-size: 1rem;
}

.examples {
  display: grid;
  gap: 10px;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
}

.example-btn {
  text-align: left;
  background: var(--bg-elevated);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 14px 16px;
}

.message {
  display: grid;
  gap: 10px;
  margin-bottom: 18px;
  animation: fadeIn 0.25s ease;
}

.message-card {
  max-width: 900px;
  padding: 16px 18px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  line-height: 1.6;
  white-space: pre-wrap;
}

.message.user .message-card {
  background: var(--user);
  margin-left: auto;
}

.message.assistant .message-card {
  background: var(--assistant);
}

.message-meta {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  color: var(--muted);
  font-size: 0.82rem;
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  border-radius: 999px;
  background: rgba(79, 140, 255, 0.12);
  border: 1px solid rgba(79, 140, 255, 0.25);
  color: #b9d2ff;
}

.citations {
  display: grid;
  gap: 10px;
  margin-top: 4px;
}

.citation {
  background: rgba(8, 14, 24, 0.55);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 12px 14px;
}

.citation summary {
  cursor: pointer;
  font-weight: 600;
}

.citation p {
  margin: 10px 0 0;
  color: var(--muted);
  line-height: 1.5;
  white-space: pre-wrap;
}

.composer {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 12px;
  padding: 18px 28px 24px;
  border-top: 1px solid rgba(42, 54, 80, 0.65);
  background: rgba(10, 16, 28, 0.72);
}

.status.loading {
  color: #ffd27d;
}

.status.error {
  color: var(--danger);
}

.status.ok {
  color: var(--success);
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(6px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (max-width: 900px) {
  .app {
    grid-template-columns: 1fr;
  }

  .sidebar {
    border-right: 0;
    border-bottom: 1px solid var(--border);
  }

  .composer {
    grid-template-columns: 1fr;
  }
}