:root {
  color-scheme: light dark;
  --bg: #ffffff;
  --sidebar-bg: #f7f7f8;
  --border: #e5e5e5;
  --text: #1f1f1f;
  --muted: #6b7280;
  --accent: #2563eb;
  --bubble-user: #2563eb;
  --bubble-user-text: #ffffff;
  --bubble-assistant: #f1f1f3;
  --bubble-assistant-text: #1f1f1f;
  --danger: #dc2626;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #1b1c1f;
    --sidebar-bg: #141518;
    --border: #2d2e33;
    --text: #e8e8ea;
    --muted: #9aa0a6;
    --bubble-user: #2563eb;
    --bubble-user-text: #ffffff;
    --bubble-assistant: #2a2b30;
    --bubble-assistant-text: #e8e8ea;
  }
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  height: 100vh;
  overflow: hidden;
}

.app {
  display: flex;
  height: 100vh;
}

.sidebar {
  width: 260px;
  flex-shrink: 0;
  background: var(--sidebar-bg);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  padding: 12px;
  overflow-y: auto;
}

.new-chat-btn {
  padding: 10px 12px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--bg);
  color: var(--text);
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  margin-bottom: 12px;
}

.new-chat-btn:hover {
  background: var(--border);
}

.session-list {
  display: flex;
  flex-direction: column;
  gap: 4px;
  overflow-y: auto;
}

.session-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 6px;
  padding: 8px 10px;
  border-radius: 8px;
  cursor: pointer;
  font-size: 13px;
  color: var(--text);
}

.session-item:hover {
  background: var(--border);
}

.session-item.active {
  background: var(--accent);
  color: #fff;
}

.session-title {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  flex: 1;
}

/* Chat with a reply still streaming. */
.session-item.generating .session-title::before {
  content: "● ";
  animation: pulse 1.2s ease-in-out infinite;
}

@keyframes pulse {
  50% { opacity: 0.3; }
}

.session-delete {
  border: none;
  background: transparent;
  color: inherit;
  opacity: 0.6;
  cursor: pointer;
  font-size: 14px;
  line-height: 1;
  padding: 2px 4px;
  border-radius: 4px;
}

.session-delete:hover {
  opacity: 1;
  background: rgba(0, 0, 0, 0.15);
}

.main {
  flex: 1;
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.chat-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 20px;
  border-bottom: 1px solid var(--border);
  font-weight: 600;
  gap: 12px;
}

.chat-header-title {
  display: flex;
  align-items: center;
  gap: 8px;
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.status-dot {
  width: 9px;
  height: 9px;
  flex-shrink: 0;
  border-radius: 50%;
  background: #16a34a;
}

.status-dot.down {
  background: var(--danger);
}

.token-badge {
  flex-shrink: 0;
  font-size: 12px;
  font-weight: 500;
  color: var(--muted);
  padding: 4px 10px;
  border: 1px solid var(--border);
  border-radius: 999px;
}

.token-badge.limit-reached {
  color: var(--danger);
  border-color: var(--danger);
}

.messages {
  flex: 1;
  overflow-y: auto;
  padding: 20px;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.message {
  max-width: 70%;
  padding: 10px 14px;
  border-radius: 14px;
  font-size: 14px;
  line-height: 1.5;
  white-space: pre-wrap;
  word-wrap: break-word;
}

.message.user {
  align-self: flex-end;
  background: var(--bubble-user);
  color: var(--bubble-user-text);
  border-bottom-right-radius: 4px;
}

.message.assistant {
  align-self: flex-start;
  background: var(--bubble-assistant);
  color: var(--bubble-assistant-text);
  border-bottom-left-radius: 4px;
}

.message.system-note {
  align-self: center;
  background: transparent;
  border: 1px dashed var(--border);
  color: var(--muted);
  font-size: 12px;
  max-width: 90%;
}

.message .think-block {
  margin-bottom: 8px;
  padding: 6px 10px;
  border-left: 3px solid var(--muted);
  color: var(--muted);
  font-size: 13px;
  font-style: italic;
  white-space: pre-wrap;
}

.message .think-block summary {
  cursor: pointer;
  font-style: normal;
  font-weight: 600;
  user-select: none;
}

.message .think-block[hidden] {
  display: none;
}

.message .pending {
  color: var(--muted);
  font-style: italic;
}

.chat-form {
  display: flex;
  gap: 10px;
  padding: 14px 20px;
  border-top: 1px solid var(--border);
}

.chat-form textarea {
  flex: 1;
  resize: none;
  max-height: 160px;
  padding: 10px 12px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: var(--bg);
  color: var(--text);
  font-size: 14px;
  font-family: inherit;
}

.chat-form button {
  padding: 0 18px;
  border-radius: 10px;
  border: none;
  background: var(--accent);
  color: #fff;
  font-weight: 600;
  cursor: pointer;
}

.chat-form button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

@media (max-width: 700px) {
  .app {
    flex-direction: column;
  }

  .sidebar {
    width: 100%;
    max-height: 30vh;
    border-right: none;
    border-bottom: 1px solid var(--border);
  }

  .message {
    max-width: 90%;
  }
}

/* ---- login page ---- */

.login-body {
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: auto;
}

.login-card {
  width: min(360px, calc(100vw - 32px));
  padding: 28px 24px;
  border: 1px solid var(--border);
  border-radius: 14px;
  background: var(--sidebar-bg);
}

.login-card h1 {
  margin: 0;
  font-size: 22px;
}

.login-subtitle {
  margin: 4px 0 20px;
  color: var(--muted);
  font-size: 14px;
}

.login-form {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.login-form label {
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-size: 13px;
  font-weight: 600;
}

.login-form input {
  padding: 10px 12px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--bg);
  color: var(--text);
  font-size: 15px;
  font-family: inherit;
}

.login-form button {
  padding: 11px;
  border: none;
  border-radius: 8px;
  background: var(--accent);
  color: #fff;
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
}

.login-form button:disabled {
  opacity: 0.6;
  cursor: wait;
}

.login-error {
  color: var(--danger);
  font-size: 13px;
}

.login-error[hidden] {
  display: none;
}

.login-note {
  margin: 18px 0 0;
  color: var(--muted);
  font-size: 12px;
}

/* ---- account box in the sidebar ---- */

.account {
  margin-top: auto;
  padding-top: 12px;
  border-top: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  font-size: 13px;
}

.account-name {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  color: var(--muted);
}

.logout-btn {
  flex-shrink: 0;
  padding: 6px 10px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--bg);
  color: var(--text);
  font-size: 12px;
  cursor: pointer;
}

.logout-btn:hover {
  background: var(--border);
}