*,
*::before,
*::after {
  box-sizing: border-box;
}

:root {
  --bg: #050608;
  --bg-alt: #0b0d12;
  --panel: #11141c;
  --panel-alt: #181c26;
  --accent: #f5d14b;
  --accent-soft: rgba(245, 209, 75, 0.1);
  --accent-strong: #ffdf5f;
  --border-subtle: #242733;
  --text: #f5f5f5;
  --text-muted: #9da3b6;
  --error: #ff6b6b;
  --user-bubble: #1f4f8a;
  --bot-bubble: #252b3a;
  --shadow-soft: 0 18px 40px rgba(0, 0, 0, 0.6);
}

html,
body {
  margin: 0;
  padding: 0;
  height: 100%;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI",
    sans-serif;
  background: radial-gradient(circle at top, #151a26 0, #050608 55%);
  color: var(--text);
}

body {
  display: flex;
  flex-direction: column;
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 1.25rem;
  border-bottom: 1px solid var(--border-subtle);
  background: linear-gradient(
    to right,
    rgba(8, 10, 18, 0.98),
    rgba(12, 16, 30, 0.98)
  );
  backdrop-filter: blur(16px);
  position: sticky;
  top: 0;
  z-index: 10;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.logo-dot {
  width: 16px;
  height: 16px;
  border-radius: 999px;
  background: radial-gradient(circle at 30% 20%, #ffffff, var(--accent-strong));
  box-shadow: 0 0 18px var(--accent-soft);
}

.brand-title {
  font-weight: 600;
  letter-spacing: 0.03em;
}

.status {
  font-size: 0.8rem;
  color: var(--text-muted);
}

.layout {
  flex: 1;
  display: flex;
  flex-direction: column;
  max-width: 960px;
  margin: 0.75rem auto;
  padding: 0 0.75rem 0.75rem;
  width: 100%;
}

.chat-panel {
  flex: 1;
  background: linear-gradient(
    145deg,
    rgba(12, 16, 26, 0.96),
    rgba(10, 14, 23, 0.99)
  );
  border-radius: 14px;
  border: 1px solid var(--border-subtle);
  box-shadow: var(--shadow-soft);
  padding: 0.75rem;
  display: flex;
  flex-direction: column;
  min-height: 40vh;
}

.messages {
  flex: 1;
  overflow-y: auto;
  padding-right: 0.25rem;
}

.message {
  max-width: 80%;
  padding: 0.6rem 0.75rem;
  border-radius: 10px;
  margin: 0.4rem 0;
  font-size: 0.95rem;
  line-height: 1.4;
  white-space: pre-wrap;
}

.message.user {
  margin-left: auto;
  background: linear-gradient(135deg, var(--user-bubble), #2a6faf);
  box-shadow: 0 10px 24px rgba(0, 0, 0, 0.4);
}

.message.bot {
  margin-right: auto;
  background: radial-gradient(circle at top left, #303750, var(--bot-bubble));
  border: 1px solid rgba(255, 255, 255, 0.02);
}

.message.system {
  margin: 0.4rem auto;
  max-width: 60%;
  text-align: center;
  font-size: 0.8rem;
  color: var(--text-muted);
  background: transparent;
}

.input-panel {
  margin-top: 0.75rem;
  background: linear-gradient(
    135deg,
    rgba(12, 16, 26, 0.98),
    rgba(16, 20, 32, 0.98)
  );
  border-radius: 14px;
  border: 1px solid var(--border-subtle);
  padding: 0.75rem 0.9rem 0.9rem;
  box-shadow: var(--shadow-soft);
}

.controls-row {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 0.5rem;
}

.persona-label {
  font-size: 0.8rem;
  color: var(--text-muted);
}

.persona-select {
  flex: 1;
  padding: 0.35rem 0.5rem;
  border-radius: 6px;
  border: 1px solid var(--border-subtle);
  background: var(--panel-alt);
  color: var(--text);
  font-size: 0.85rem;
}

.input-row {
  display: flex;
  gap: 0.5rem;
  align-items: flex-end;
}

.input-box {
  flex: 1;
  resize: vertical;
  min-height: 2.4rem;
  max-height: 8rem;
  border-radius: 8px;
  border: 1px solid var(--border-subtle);
  background: var(--bg-alt);
  color: var(--text);
  padding: 0.55rem 0.6rem;
  font-size: 0.95rem;
  font-family: inherit;
}

.input-box:focus {
  outline: 1px solid var(--accent);
  box-shadow: 0 0 0 1px rgba(245, 209, 75, 0.4);
}

.send-btn {
  border-radius: 999px;
  border: none;
  padding: 0.55rem 1.1rem;
  font-size: 0.95rem;
  font-weight: 500;
  background: radial-gradient(circle at 20% 0%, var(--accent-strong), #f3b53d);
  color: #121212;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  box-shadow: 0 10px 22px rgba(0, 0, 0, 0.7);
}

.send-btn:disabled {
  opacity: 0.6;
  cursor: default;
  box-shadow: none;
}

.send-btn::after {
  content: "↗";
  font-size: 0.85rem;
}

.hint {
  margin-top: 0.3rem;
  font-size: 0.75rem;
  color: var(--text-muted);
}

.footer {
  padding: 0.4rem 1rem 0.8rem;
  text-align: center;
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* small screens */
@media (max-width: 640px) {
  .layout {
    margin-top: 0.5rem;
    padding: 0 0.5rem 0.5rem;
  }
  .chat-panel {
    min-height: 45vh;
  }
  .message {
    max-width: 88%;
  }
}