:root {
  color-scheme: dark;
  --bg: #0c0f14;
  --panel: #121723;
  --panel-soft: #1a2232;
  --text: #e7edf7;
  --muted: #99a4b8;
  --accent: #4a8dff;
  --error: #ff6b6b;
  --user: #2f4f85;
  --assistant: #1f2a3f;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: Inter, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: radial-gradient(circle at top, #1a2233 0%, var(--bg) 55%);
  color: var(--text);
  min-height: 100vh;
}

.app-shell {
  max-width: 980px;
  margin: 24px auto;
  padding: 16px;
  display: grid;
  grid-template-rows: auto auto 1fr auto;
  gap: 14px;
  min-height: calc(100vh - 48px);
}

.topbar {
  background: var(--panel);
  border: 1px solid #263149;
  border-radius: 14px;
  padding: 16px;
  display: flex;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}

.topbar h1 {
  margin: 0 0 4px;
  font-size: 1.35rem;
}

.subtitle {
  margin: 0;
  color: var(--muted);
}

.model-controls {
  display: grid;
  grid-template-columns: 1fr;
  gap: 6px;
  min-width: 260px;
}

select,
textarea,
button {
  border-radius: 10px;
  border: 1px solid #2b3954;
  background: var(--panel-soft);
  color: var(--text);
  padding: 10px 12px;
  font: inherit;
}

button {
  cursor: pointer;
  background: var(--accent);
  border-color: #3f73cc;
  font-weight: 600;
}

button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.chat-window {
  background: var(--panel);
  border: 1px solid #263149;
  border-radius: 14px;
  padding: 16px;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.message {
  border-radius: 12px;
  padding: 10px 12px;
  max-width: 80%;
  border: 1px solid #2d3a52;
}

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

.message.assistant {
  margin-right: auto;
  background: var(--assistant);
}

.role {
  margin: 0 0 6px;
  color: #c4d3ef;
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.content {
  margin: 0;
  line-height: 1.45;
  white-space: pre-wrap;
  word-wrap: break-word;
}

.composer {
  background: var(--panel);
  border: 1px solid #263149;
  border-radius: 14px;
  padding: 16px;
}

.composer-form {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 10px;
}

textarea {
  resize: vertical;
  min-height: 74px;
}

.loading-state {
  color: var(--muted);
  margin-top: 8px;
}

.error-banner {
  border: 1px solid #773636;
  background: #331b1b;
  color: var(--error);
  border-radius: 10px;
  padding: 10px 12px;
}

.hidden {
  display: none;
}

@media (max-width: 700px) {
  .composer-form {
    grid-template-columns: 1fr;
  }

  .message {
    max-width: 95%;
  }
}