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

:root {
  --bg: #f1f5f9;
  --panel: #ffffff;
  --text: #111827;
  --muted: #64748b;
  --border: #e2e8f0;
  --primary: #4f46e5;
  --primary-2: #4338ca;
  --sidebar: #1f1d58;
  --bot: #ffffff;
  --user: #4f46e5;
  --error: #ef4444;
}

html, body {
  margin: 0;
  height: 100%;
  font-family: Inter, system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
}

.app {
  display: grid;
  grid-template-columns: 290px 1fr;
  height: 100vh;
  overflow: hidden;
}

.sidebar {
  background: var(--sidebar);
  color: #dbeafe;
  padding: 18px;
  display: flex;
  flex-direction: column;
  gap: 18px;
  border-right: 1px solid rgba(255, 255, 255, 0.08);
}

.sidebar-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  padding-bottom: 14px;
  border-bottom: 1px solid rgba(255,255,255,0.08);
}

.brand-icon {
  font-size: 23px;
}

.brand-name {
  margin: 0;
  color: #fff;
  font-size: 19px;
  font-weight: 700;
}

.brand-sub {
  margin: 1px 0 0;
  color: #a5b4fc;
  font-size: 12px;
}

.sidebar-section {
  display: flex;
  flex-direction: column;
  gap: 7px;
}

.sidebar-label {
  margin: 0;
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: #9ca3af;
  font-weight: 600;
}

.sidebar-input {
  width: 100%;
  border: 1px solid rgba(255,255,255,0.14);
  background: rgba(255,255,255,0.07);
  color: #e5e7eb;
  border-radius: 10px;
  padding: 11px 12px;
  font-size: 13px;
  outline: none;
}

.sidebar-input:focus {
  border-color: #818cf8;
}

.sidebar-input::placeholder {
  color: #94a3b8;
}

.sidebar-hint {
  margin: 0;
  font-size: 11px;
  color: #94a3b8;
}

.env-toggle {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 7px;
}

.env-btn {
  border: 1px solid rgba(255,255,255,0.16);
  background: rgba(255,255,255,0.06);
  color: #cbd5e1;
  border-radius: 10px;
  padding: 8px;
  font-size: 12px;
  cursor: pointer;
}

.env-btn.active {
  background: #4f46e5;
  color: #fff;
  border-color: #4f46e5;
}

.sidebar-actions {
  display: grid;
  gap: 8px;
}

.action-btn {
  display: flex;
  align-items: center;
  gap: 7px;
  border: 1px solid rgba(255,255,255,0.14);
  background: rgba(255,255,255,0.06);
  color: #e5e7eb;
  border-radius: 10px;
  padding: 10px 12px;
  font-size: 13px;
  cursor: pointer;
}

.action-btn.history:hover {
  border-color: #818cf8;
}

.action-btn.danger {
  border-color: rgba(239,68,68,0.35);
  color: #fca5a5;
}

.action-btn.danger:hover {
  background: rgba(239,68,68,0.12);
}

.sidebar-footer {
  margin-top: auto;
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.footer-badge {
  background: rgba(255,255,255,0.08);
  border: 1px solid rgba(255,255,255,0.12);
  color: #cbd5e1;
  padding: 5px 8px;
  border-radius: 999px;
  font-size: 10px;
}

.chat-area {
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.chat-header {
  background: var(--panel);
  border-bottom: 1px solid var(--border);
  padding: 14px 18px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
}

.header-left {
  display: flex;
  align-items: center;
  gap: 10px;
}

.header-avatar {
  width: 38px;
  height: 38px;
  border-radius: 999px;
  display: grid;
  place-items: center;
  background: #e0e7ff;
  font-size: 18px;
}

.header-name {
  margin: 0;
  font-weight: 700;
  font-size: 15px;
}

.header-status {
  margin: 2px 0 0;
  color: var(--muted);
  font-size: 12px;
  display: flex;
  align-items: center;
  gap: 6px;
}

.status-dot {
  width: 8px;
  height: 8px;
  border-radius: 999px;
  background: #22c55e;
}

.header-subjects {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.subject-tag {
  font-size: 11px;
  color: #475569;
  border: 1px solid var(--border);
  background: #fff;
  padding: 4px 8px;
  border-radius: 999px;
}

.history-panel {
  margin: 10px 16px 0;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 14px;
  overflow: hidden;
}

.history-panel-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px 12px;
  border-bottom: 1px solid var(--border);
}

.history-panel-header p {
  margin: 0;
  font-weight: 600;
  font-size: 13px;
}

.history-panel-header button {
  border: 0;
  background: transparent;
  color: #64748b;
  cursor: pointer;
}

.history-list {
  max-height: 180px;
  overflow: auto;
  padding: 10px 12px;
  font-size: 12px;
  color: #334155;
  line-height: 1.5;
}

.messages {
  flex: 1;
  overflow: auto;
  padding: 18px;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.message {
  display: flex;
  align-items: flex-end;
  gap: 10px;
  max-width: 78%;
}

.message.bot { align-self: flex-start; }
.message.user { align-self: flex-end; flex-direction: row-reverse; }

.avatar {
  width: 34px;
  height: 34px;
  border-radius: 999px;
  display: grid;
  place-items: center;
  background: #e0e7ff;
  font-size: 16px;
  flex-shrink: 0;
}

.message.user .avatar {
  background: var(--primary);
  color: #fff;
  font-size: 11px;
  font-weight: 700;
}

.bubble-wrap {
  display: grid;
  gap: 4px;
}

.bubble {
  background: var(--bot);
  border: 1px solid var(--border);
  color: #111827;
  padding: 11px 13px;
  border-radius: 14px;
  line-height: 1.6;
  font-size: 13px;
  word-break: break-word;
}

.message.user .bubble {
  background: var(--user);
  color: #fff;
  border-color: var(--user);
}

.message.error .bubble {
  background: #fef2f2;
  border-color: #fecaca;
  color: var(--error);
}

.timestamp {
  font-size: 10px;
  color: #94a3b8;
  padding: 0 4px;
}

.typing .dot {
  display: inline-block;
  width: 6px;
  height: 6px;
  border-radius: 999px;
  background: #64748b;
  margin-right: 4px;
  animation: bounce 1.2s infinite;
}

.typing .dot:nth-child(2) { animation-delay: .2s; }
.typing .dot:nth-child(3) { animation-delay: .4s; margin-right: 0; }

@keyframes bounce {
  0%, 80%, 100% { transform: translateY(0); opacity: .6; }
  40% { transform: translateY(-4px); opacity: 1; }
}

.chat-input-area {
  background: #fff;
  border-top: 1px solid var(--border);
  padding: 12px 16px;
}

.input-wrap {
  display: grid;
  grid-template-columns: 1fr 46px;
  gap: 8px;
  align-items: end;
}

.chat-input {
  resize: none;
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 11px 13px;
  font-size: 13px;
  font-family: inherit;
  min-height: 44px;
  max-height: 140px;
  outline: none;
  line-height: 1.5;
  background: #f8fafc;
}

.chat-input:focus {
  border-color: #818cf8;
}

.send-btn {
  width: 46px;
  height: 44px;
  border: 0;
  border-radius: 12px;
  background: var(--primary);
  color: #fff;
  display: grid;
  place-items: center;
  cursor: pointer;
}

.send-btn:hover {
  background: var(--primary-2);
}

.send-btn:disabled {
  cursor: not-allowed;
  background: #94a3b8;
}

.input-hint {
  margin: 6px 2px 0;
  color: #94a3b8;
  font-size: 11px;
}

.messages::-webkit-scrollbar,
.history-list::-webkit-scrollbar { width: 6px; }

.messages::-webkit-scrollbar-thumb,
.history-list::-webkit-scrollbar-thumb {
  background: #cbd5e1;
  border-radius: 99px;
}

@media (max-width: 900px) {
  .app { grid-template-columns: 1fr; }
  .sidebar { display: none; }
  .message { max-width: 92%; }
  .chat-header { flex-direction: column; align-items: flex-start; }
}