*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg: #1a1a2e;
  --surface: #16213e;
  --surface2: #0f3460;
  --text: #e0e0e0;
  --text-dim: #8a8a9a;
  --accent: #0ea5e9;
  --accent-hover: #38bdf8;
  --border: #2a2a4a;
  --user-bg: #0f3460;
  --assistant-bg: #1e1e3a;
  --error: #ef4444;
  --radius: 8px;
}

html, body { height: 100%; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, monospace; background: var(--bg); color: var(--text); }

#app {
  display: flex;
  height: 100vh;
  flex-direction: row;
}

/* Sidebar */
#sidebar {
  width: 240px;
  min-width: 200px;
  background: var(--surface);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  overflow-y: auto;
}
.sidebar-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px;
  border-bottom: 1px solid var(--border);
}
.sidebar-header h2 { font-size: 14px; font-weight: 600; }
#new-session {
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 4px;
  width: 28px;
  height: 28px;
  font-size: 18px;
  cursor: pointer;
  line-height: 1;
}
#new-session:hover { background: var(--accent-hover); }

#session-list { list-style: none; padding: 8px; }
#session-list li {
  padding: 8px 12px;
  border-radius: var(--radius);
  cursor: pointer;
  font-size: 13px;
  color: var(--text-dim);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  margin-bottom: 2px;
}
#session-list li:hover { background: var(--surface2); color: var(--text); }
#session-list li.active { background: var(--surface2); color: var(--accent); font-weight: 600; }

/* Chat */
#chat {
  flex: 1;
  display: flex;
  flex-direction: column;
  min-width: 0;
}
#messages {
  flex: 1;
  overflow-y: auto;
  padding: 24px;
}
.message {
  max-width: 720px;
  margin: 0 auto 16px;
  padding: 12px 16px;
  border-radius: var(--radius);
  font-size: 14px;
  line-height: 1.6;
  white-space: pre-wrap;
  word-break: break-word;
}
.message.user { background: var(--user-bg); margin-left: 80px; }
.message.assistant { background: var(--assistant-bg); margin-right: 80px; }
.message .role { font-size: 11px; font-weight: 700; text-transform: uppercase; color: var(--text-dim); margin-bottom: 4px; }
.message.user .role { color: var(--accent); }

/* Chat form */
#chat-form {
  display: flex;
  gap: 8px;
  padding: 16px 24px;
  border-top: 1px solid var(--border);
  background: var(--surface);
}
#input {
  flex: 1;
  background: var(--bg);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 10px 14px;
  font-size: 14px;
  font-family: inherit;
  resize: none;
}
#input:focus { outline: none; border-color: var(--accent); }
#chat-form button {
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: var(--radius);
  padding: 10px 20px;
  font-size: 14px;
  cursor: pointer;
  white-space: nowrap;
}
#chat-form button:hover { background: var(--accent-hover); }
#chat-form button:disabled { opacity: 0.5; cursor: not-allowed; }

/* Status bar */
#status-bar {
  padding: 6px 16px;
  font-size: 12px;
  color: var(--text-dim);
  background: var(--surface);
  border-top: 1px solid var(--border);
  text-align: center;
}

/* Auth modal */
.modal {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.6);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
}
.modal.hidden { display: none; }
.modal-content {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px;
  display: flex;
  flex-direction: column;
  gap: 16px;
  min-width: 320px;
}
.modal-content h3 { font-size: 16px; }
.modal-content input {
  background: var(--bg);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 10px;
  font-size: 14px;
}
.modal-content button {
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 4px;
  padding: 10px;
  font-size: 14px;
  cursor: pointer;
}

/* Streaming indicator */
.streaming::after {
  content: "";
  display: inline-block;
  width: 6px;
  height: 14px;
  background: var(--accent);
  margin-left: 2px;
  animation: blink 0.8s steps(2) infinite;
  vertical-align: text-bottom;
}
@keyframes blink { 50% { opacity: 0; } }

/* Responsive */
@media (max-width: 640px) {
  #sidebar { display: none; }
  .message.user { margin-left: 20px; }
  .message.assistant { margin-right: 20px; }
}