:root {
  --bg: #0f1419;
  --panel: #1a222c;
  --border: #2c3845;
  --text: #e7eef5;
  --muted: #8b9aab;
  --accent: #3d8bfd;
  --user: #243044;
  --assistant: #1c262f;
  --pending: #c9a227;
  --danger: #e35d6a;
  --font: "IBM Plex Sans", "Segoe UI", system-ui, sans-serif;
  --mono: "IBM Plex Mono", ui-monospace, monospace;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font);
  background:
    radial-gradient(1200px 600px at 10% -10%, #1a3350 0%, transparent 55%),
    var(--bg);
  color: var(--text);
}

.app {
  max-width: 860px;
  margin: 0 auto;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  padding: 1rem 1rem 0;
}

.header {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  align-items: flex-start;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--border);
}

h1 {
  margin: 0;
  font-size: 1.4rem;
  letter-spacing: -0.02em;
}

.sub, .meta {
  margin: 0.25rem 0 0;
  color: var(--muted);
  font-size: 0.85rem;
}

.meta { text-align: right; font-family: var(--mono); }

.chat {
  flex: 1;
  overflow-y: auto;
  padding: 1rem 0 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.msg {
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 0.85rem 1rem;
  background: var(--assistant);
  white-space: pre-wrap;
  word-break: break-word;
  line-height: 1.45;
}

.msg.user { background: var(--user); align-self: flex-end; max-width: 92%; }
.msg.assistant { align-self: stretch; }

.msg .role {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 0.75rem;
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  color: var(--muted);
  margin-bottom: 0.35rem;
  font-family: var(--mono);
}

.msg .role-name {
  text-transform: uppercase;
}

.msg .ts {
  flex-shrink: 0;
  text-transform: none;
  letter-spacing: 0;
  font-variant-numeric: tabular-nums;
  color: var(--muted);
  opacity: 0.9;
  cursor: default;
  user-select: all;
}

.msg.pending .role { color: var(--pending); }
.msg.failed .role { color: var(--danger); }
.msg.near-limit .role,
.msg .elapsed.near-limit { color: var(--danger); }

.msg .elapsed {
  font-variant-numeric: tabular-nums;
}

.msg .think-hint {
  margin-top: 0.45rem;
  font-size: 0.78rem;
  color: var(--muted);
  font-family: var(--mono);
}

.msg .sources {
  margin-top: 0.6rem;
  padding-top: 0.5rem;
  border-top: 1px dashed var(--border);
  font-size: 0.8rem;
  color: var(--muted);
  font-family: var(--mono);
}

.composer {
  position: sticky;
  bottom: 0;
  background: linear-gradient(transparent, var(--bg) 30%);
  padding: 0.5rem 0 1rem;
}

.hints {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  align-items: center;
  color: var(--muted);
  font-size: 0.8rem;
  margin-bottom: 0.5rem;
}

.hints button {
  border: 1px solid var(--border);
  background: var(--panel);
  color: var(--text);
  border-radius: 999px;
  padding: 0.2rem 0.65rem;
  cursor: pointer;
  font: inherit;
  font-size: 0.78rem;
}

.hints button:hover { border-color: var(--accent); }

#form {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 0.6rem;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 0.65rem;
}

textarea {
  resize: vertical;
  min-height: 2.8rem;
  max-height: 10rem;
  border: 0;
  background: transparent;
  color: var(--text);
  font: inherit;
  outline: none;
}

#send {
  align-self: end;
  border: 0;
  border-radius: 10px;
  background: var(--accent);
  color: #fff;
  font: inherit;
  font-weight: 600;
  padding: 0.65rem 1rem;
  cursor: pointer;
}

#send:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.empty {
  color: var(--muted);
  text-align: center;
  margin: 3rem 0;
}