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

:root {
  --bg: #0f0f0f;
  --bg2: #1a1a1a;
  --bg3: #242424;
  --border: #333;
  --text: #e0e0e0;
  --text2: #999;
  --accent: #6c5ce7;
  --accent2: #a29bfe;
  --green: #00b894;
  --danger: #e17055;
  --radius: 12px;
  --shadow: 0 4px 20px rgba(0,0,0,.4);
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  height: 100vh;
  overflow: hidden;
}

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

/* Login */
#login-screen {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100vh;
  background: radial-gradient(ellipse at center, #1a1a2e 0%, #0f0f0f 70%);
}

.login-box {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 40px;
  width: 360px;
  text-align: center;
  box-shadow: var(--shadow);
}

.login-logo { margin-bottom: 24px; }
.logo-icon { font-size: 48px; }
.login-logo h1 { font-size: 28px; margin: 8px 0 4px; color: var(--accent2); }
.login-subtitle { color: var(--text2); font-size: 14px; }

.login-form input {
  width: 100%;
  padding: 12px 16px;
  margin-bottom: 12px;
  background: var(--bg3);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text);
  font-size: 14px;
  outline: none;
  transition: border .2s;
}
.login-form input:focus { border-color: var(--accent); }

#login-btn {
  width: 100%;
  padding: 12px;
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 8px;
  font-size: 16px;
  cursor: pointer;
  font-weight: 600;
  transition: background .2s;
}
#login-btn:hover { background: #5a4bd1; }

.error-msg { color: var(--danger); font-size: 13px; margin-top: 12px; min-height: 20px; }

/* Chat screen */
#chat-screen {
  display: flex;
  height: 100vh;
}

/* Sidebar */
#sidebar {
  width: 280px;
  min-width: 280px;
  background: var(--bg2);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  transition: margin-left .3s;
}

.sidebar-header {
  padding: 16px;
  display: flex;
  align-items: center;
  gap: 10px;
  border-bottom: 1px solid var(--border);
}
.sidebar-header .logo-icon { font-size: 24px; }
.sidebar-header h2 { font-size: 18px; color: var(--accent2); }

#new-chat-btn {
  margin: 12px;
  padding: 10px;
  background: var(--bg3);
  border: 1px dashed var(--border);
  border-radius: 8px;
  color: var(--text2);
  cursor: pointer;
  font-size: 13px;
  transition: all .2s;
}
#new-chat-btn:hover { border-color: var(--accent); color: var(--text); }

#conversation-list { flex: 1; overflow-y: auto; padding: 4px 8px; }
.conv-item {
  padding: 10px 12px;
  border-radius: 8px;
  cursor: pointer;
  margin-bottom: 2px;
  transition: background .2s;
  position: relative;
}
.conv-item:hover { background: var(--bg3); }
.conv-item.active { background: var(--bg3); border-left: 3px solid var(--accent); }
.conv-item .conv-title { font-size: 13px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.conv-item .conv-meta { font-size: 11px; color: var(--text2); margin-top: 2px; }
.conv-item .conv-delete {
  position: absolute; right: 8px; top: 50%; transform: translateY(-50%);
  opacity: 0; background: none; border: none; color: var(--danger); cursor: pointer; font-size: 16px;
}
.conv-item:hover .conv-delete { opacity: 1; }

.sidebar-footer {
  padding: 12px;
  border-top: 1px solid var(--border);
  display: flex;
  gap: 8px;
}

.small-btn {
  flex: 1;
  padding: 8px;
  background: var(--bg3);
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--text2);
  cursor: pointer;
  font-size: 12px;
  transition: all .2s;
}
.small-btn:hover { border-color: var(--accent); color: var(--text); }

/* Main area */
#main-area {
  flex: 1;
  display: flex;
  flex-direction: column;
  min-width: 0;
}

#chat-header {
  padding: 12px 20px;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  gap: 12px;
  background: var(--bg2);
}

#menu-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--text);
  font-size: 20px;
  cursor: pointer;
}

#current-title { font-weight: 600; flex: 1; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.project-badge {
  padding: 4px 10px;
  border-radius: 20px;
  font-size: 11px;
  font-weight: 600;
  background: var(--accent);
  color: #fff;
}

/* Messages */
#messages-container {
  flex: 1;
  overflow-y: auto;
  padding: 20px;
}

.message {
  margin-bottom: 20px;
  max-width: 80%;
  animation: fadeIn .3s;
}

@keyframes fadeIn { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: translateY(0); } }

.message.user { margin-left: auto; }
.message.assistant { margin-right: auto; }

.msg-content {
  padding: 12px 16px;
  border-radius: var(--radius);
  line-height: 1.6;
  font-size: 14px;
  white-space: pre-wrap;
  word-wrap: break-word;
}

.message.user .msg-content {
  background: var(--accent);
  color: #fff;
  border-bottom-right-radius: 4px;
}

.message.assistant .msg-content {
  background: var(--bg3);
  border: 1px solid var(--border);
  border-bottom-left-radius: 4px;
}

.msg-content code {
  background: rgba(255,255,255,.1);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 13px;
  font-family: 'SF Mono', 'Fira Code', monospace;
}

.msg-content pre {
  background: #111;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 12px;
  margin: 8px 0;
  overflow-x: auto;
}

.msg-content pre code {
  background: none;
  padding: 0;
}

.msg-time {
  font-size: 11px;
  color: var(--text2);
  margin-top: 4px;
  padding: 0 4px;
}

.message.user .msg-time { text-align: right; }

/* Input */
#input-area {
  padding: 12px 20px;
  border-top: 1px solid var(--border);
  background: var(--bg2);
  display: flex;
  gap: 8px;
  align-items: flex-end;
}

#message-input {
  flex: 1;
  padding: 12px 16px;
  background: var(--bg3);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
  font-size: 14px;
  outline: none;
  resize: none;
  max-height: 150px;
  line-height: 1.4;
  transition: border .2s;
}
#message-input:focus { border-color: var(--accent); }
#message-input::placeholder { color: var(--text2); }

#send-btn {
  width: 44px;
  height: 44px;
  background: var(--accent);
  border: none;
  border-radius: 50%;
  color: #fff;
  font-size: 18px;
  cursor: pointer;
  transition: background .2s;
  display: flex;
  align-items: center;
  justify-content: center;
}
#send-btn:hover { background: #5a4bd1; }
#send-btn:disabled { background: var(--bg3); color: var(--text2); cursor: not-allowed; }

/* Typing indicator */
.typing .msg-content::after {
  content: '...';
  animation: blink 1.5s infinite;
}
@keyframes blink { 0%, 100% { opacity: 1; } 50% { opacity: .3; } }

/* Overlays */
#new-conversation-overlay, #stats-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,.7);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
}

.overlay-content {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 32px;
  width: 400px;
  box-shadow: var(--shadow);
}

.overlay-content h2 { margin-bottom: 20px; font-size: 20px; }

.overlay-content input,
.overlay-content select {
  width: 100%;
  padding: 10px 14px;
  margin-bottom: 12px;
  background: var(--bg3);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text);
  font-size: 14px;
  outline: none;
}

.overlay-content select { appearance: auto; }
.overlay-content input:focus { border-color: var(--accent); }

.overlay-buttons { display: flex; gap: 8px; margin-top: 8px; }

.overlay-content button {
  flex: 1;
  padding: 10px;
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 8px;
  font-size: 14px;
  cursor: pointer;
  font-weight: 600;
}
.overlay-content button.secondary {
  background: var(--bg3);
  color: var(--text2);
  border: 1px solid var(--border);
}

.hidden { display: none !important; }

/* Welcome screen */
.welcome-msg {
  text-align: center;
  padding: 60px 20px;
  color: var(--text2);
}
.welcome-msg .big-icon { font-size: 64px; margin-bottom: 16px; }
.welcome-msg h2 { font-size: 24px; color: var(--text); margin-bottom: 8px; }
.welcome-msg p { font-size: 14px; line-height: 1.6; }

/* Stats */
.stat-row { display: flex; justify-content: space-between; padding: 8px 0; border-bottom: 1px solid var(--border); font-size: 14px; }

/* Responsive */
@media (max-width: 768px) {
  #sidebar { position: fixed; left: 0; top: 0; bottom: 0; z-index: 50; margin-left: -280px; }
  #sidebar.open { margin-left: 0; }
  #menu-toggle { display: block; }
  .message { max-width: 90%; }
}