:root {
  --color-brand-primary: #1e7a5a;
  --color-brand-hover: #17684c;
  --color-brand-pressed: #145c43;
  --color-brand-soft: #eef4f1;
  --color-surface-page: #f6f7f9;
  --color-surface-card: #ffffff;
  --color-surface-subtle: #fbfcfd;
  --color-surface-disabled: #eef1f3;
  --color-text-primary: #1e2329;
  --color-text-secondary: #66707a;
  --color-text-tertiary: #8b949e;
  --color-text-inverse: #ffffff;
  --color-border-default: #d9dee3;
  --color-border-subtle: #eef1f3;
  --color-info: #2563eb;
  --color-info-soft: #eff6ff;
  --color-success: #1e7a5a;
  --color-success-soft: #e8f3ee;
  --color-warning: #8a560c;
  --color-warning-soft: #fff4df;
  --color-danger: #b83b36;
  --color-danger-hover: #962f2b;
  --color-danger-soft: #fff0ef;
  --color-overlay: rgba(20, 32, 46, 0.42);
  --font-family-sans: -apple-system, BlinkMacSystemFont, "SF Pro Text", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-size-page: 24px;
  --font-size-section: 18px;
  --font-size-card: 16px;
  --font-size-body: 14px;
  --font-size-caption: 12px;
  --font-size-button: 14px;
  --font-size-tag: 12px;
  --font-size-metric: 24px;
  --line-height-tight: 1.3;
  --line-height-title: 1.4;
  --line-height-body: 1.6;
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 20px;
  --space-6: 24px;
  --space-8: 32px;
  --radius-control: 6px;
  --radius-card: 8px;
  --radius-dialog: 12px;
  --radius-round: 999px;
  --shadow-card: 0 8px 24px rgba(20, 32, 46, 0.06);
  --shadow-overlay: 0 20px 48px rgba(20, 32, 46, 0.16);
  --motion-fast: 120ms;
  --motion-normal: 180ms;
  --motion-slow: 240ms;
  --ease-standard: cubic-bezier(.2, 0, 0, 1);
  --control-height: 40px;
  --control-height-compact: 32px;
  --layout-max: 1440px;

  /* Compatibility aliases. New code uses semantic tokens above. */
  --bg: var(--color-surface-page);
  --surface: var(--color-surface-card);
  --panel: var(--color-surface-card);
  --text: var(--color-text-primary);
  --muted: var(--color-text-secondary);
  --line: var(--color-border-default);
  --primary: var(--color-brand-primary);
  --primary-soft: var(--color-brand-soft);
  --danger: var(--color-danger);
}

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

body {
  margin: 0;
  background: var(--color-surface-page);
  color: var(--color-text-primary);
  font-family: var(--font-family-sans);
  font-size: var(--font-size-body);
  line-height: var(--line-height-body);
  -webkit-font-smoothing: antialiased;
}

button, input, textarea, select { font: inherit; }
button { transition: color var(--motion-fast) var(--ease-standard), background-color var(--motion-fast) var(--ease-standard), border-color var(--motion-fast) var(--ease-standard), transform var(--motion-fast) var(--ease-standard); }
button:active:not(:disabled) { transform: scale(.99); }
button:focus-visible, input:focus-visible, textarea:focus-visible, select:focus-visible, summary:focus-visible, [tabindex]:focus-visible {
  outline: 2px solid var(--color-brand-primary);
  outline-offset: 2px;
}

.ds-page-title { margin: 0; font-size: var(--font-size-page); line-height: var(--line-height-tight); font-weight: 700; }
.ds-section-title { margin: 0; font-size: var(--font-size-section); line-height: var(--line-height-title); font-weight: 700; }
.ds-card-title { margin: 0; font-size: var(--font-size-card); line-height: var(--line-height-title); font-weight: 700; }
.ds-caption { color: var(--color-text-secondary); font-size: var(--font-size-caption); }
.ds-metric { font-size: var(--font-size-metric); line-height: 1.2; font-weight: 700; font-variant-numeric: tabular-nums; }

.ds-card {
  padding: var(--space-4);
  border: 1px solid var(--color-border-default);
  border-radius: var(--radius-card);
  background: var(--color-surface-card);
}
.ds-card[data-interactive="true"]:hover { border-color: var(--color-brand-primary); background: var(--color-surface-subtle); }

.ds-button,
:where(#loginView, .topbar, .starter-workbench, .workbench-metrics, #landlordRoomsWorkspace) :where(.primary-button, .secondary-button, .ghost-button, .danger-button) {
  min-height: var(--control-height);
  padding: 0 var(--space-4);
  border: 1px solid transparent;
  border-radius: var(--radius-control);
  font-size: var(--font-size-button);
  font-weight: 600;
  cursor: pointer;
}
.ds-button--primary,
:where(#loginView, .starter-workbench, .workbench-metrics, #landlordRoomsWorkspace) .primary-button { color: var(--color-text-inverse); background: var(--color-brand-primary); }
.ds-button--primary:hover:not(:disabled),
:where(#loginView, .starter-workbench, .workbench-metrics, #landlordRoomsWorkspace) .primary-button:hover:not(:disabled) { background: var(--color-brand-hover); }
.ds-button--primary:active:not(:disabled),
:where(#loginView, .starter-workbench, .workbench-metrics, #landlordRoomsWorkspace) .primary-button:active:not(:disabled) { background: var(--color-brand-pressed); }
.ds-button--secondary,
:where(#loginView, .starter-workbench, .workbench-metrics, #landlordRoomsWorkspace) .secondary-button { color: var(--color-brand-primary); border-color: var(--color-border-default); background: var(--color-surface-card); }
.ds-button--ghost,
:where(#loginView, .topbar, .starter-workbench, .workbench-metrics, #landlordRoomsWorkspace) .ghost-button { color: var(--color-text-secondary); background: transparent; }
.ds-button--secondary:hover:not(:disabled), .ds-button--ghost:hover:not(:disabled),
:where(#loginView, .topbar, .starter-workbench, .workbench-metrics, #landlordRoomsWorkspace) :where(.secondary-button, .ghost-button):hover:not(:disabled) { color: var(--color-brand-primary); background: var(--color-brand-soft); }
.ds-button--danger,
:where(#loginView, .starter-workbench, .workbench-metrics, #landlordRoomsWorkspace) .danger-button { color: var(--color-text-inverse); background: var(--color-danger); }
.ds-button--danger:hover:not(:disabled),
:where(#loginView, .starter-workbench, .workbench-metrics, #landlordRoomsWorkspace) .danger-button:hover:not(:disabled) { background: var(--color-danger-hover); }
.ds-button:disabled,
:where(#loginView, .topbar, .starter-workbench, .workbench-metrics, #landlordRoomsWorkspace) :where(.primary-button, .secondary-button, .ghost-button, .danger-button):disabled { color: var(--color-text-tertiary); border-color: transparent; background: var(--color-surface-disabled); cursor: not-allowed; opacity: .72; transform: none; }

.ds-field { display: grid; gap: var(--space-2); color: var(--color-text-secondary); font-size: var(--font-size-body); font-weight: 600; }
.ds-input, .ds-textarea, .ds-select,
:where(#loginView, #landlordRoomsWorkspace) :where(input:not([type="checkbox"]):not([type="radio"]), textarea, select) {
  width: 100%; min-height: var(--control-height); padding: 0 var(--space-3); border: 1px solid var(--color-border-default); border-radius: var(--radius-control); background: var(--color-surface-card); color: var(--color-text-primary);
}
.ds-textarea, :where(#loginView, #landlordRoomsWorkspace) textarea { min-height: 96px; padding-block: var(--space-3); resize: vertical; }
.ds-input::placeholder, :where(#loginView, #landlordRoomsWorkspace) :where(input, textarea)::placeholder { color: var(--color-text-tertiary); }
.ds-input:hover, :where(#loginView, #landlordRoomsWorkspace) :where(input:not([type="checkbox"]):not([type="radio"]), textarea, select):hover { border-color: var(--color-text-tertiary); }
.ds-input:focus, :where(#loginView, #landlordRoomsWorkspace) :where(input:not([type="checkbox"]):not([type="radio"]), textarea, select):focus { border-color: var(--color-brand-primary); }

.ds-tag { display: inline-flex; align-items: center; min-height: 24px; padding: 0 var(--space-2); border-radius: var(--radius-control); color: var(--color-text-secondary); background: var(--color-surface-disabled); font-size: var(--font-size-tag); font-weight: 600; }
.ds-tag--success { color: var(--color-success); background: var(--color-success-soft); }
.ds-tag--warning { color: var(--color-warning); background: var(--color-warning-soft); }
.ds-tag--danger { color: var(--color-danger); background: var(--color-danger-soft); }
.ds-tag--info { color: var(--color-info); background: var(--color-info-soft); }

.ds-table { width: 100%; border-collapse: collapse; background: var(--color-surface-card); font-size: var(--font-size-body); }
.ds-table th { height: 40px; padding: 0 var(--space-3); color: var(--color-text-secondary); background: var(--color-surface-subtle); text-align: left; font-weight: 600; }
.ds-table td { height: 48px; padding: 0 var(--space-3); border-top: 1px solid var(--color-border-subtle); }
.ds-table tbody tr:hover { background: var(--color-surface-subtle); }

.ds-empty { display: grid; place-items: center; gap: var(--space-2); min-height: 160px; padding: var(--space-8); color: var(--color-text-secondary); text-align: center; }
.ds-spinner { width: 20px; height: 20px; border: 2px solid var(--color-border-default); border-top-color: var(--color-brand-primary); border-radius: var(--radius-round); animation: ds-spin .8s linear infinite; }
.ds-skeleton { min-height: 16px; border-radius: var(--radius-control); background: var(--color-surface-disabled); animation: ds-pulse 1.2s ease-in-out infinite; }

/* Round 1: login, home and rooms. */
.topbar { min-height: 64px; padding: 0 var(--space-6); border-bottom: 1px solid var(--color-border-subtle); background: var(--color-surface-card); box-shadow: none; }
.brand-lockup h1 { font-size: var(--font-size-section); }
.brand-lockup p { color: var(--color-text-secondary); font-size: var(--font-size-caption); }
.login-shell { padding: var(--space-8) var(--space-4); }
.login-panel { width: min(100%, 420px); padding: var(--space-6); border: 1px solid var(--color-border-default); border-radius: var(--radius-dialog); background: var(--color-surface-card); box-shadow: var(--shadow-card); }
.login-panel h2 { margin: 0 0 var(--space-6); font-size: var(--font-size-page); }
.login-form { gap: var(--space-4); }
.login-form label { gap: var(--space-2); color: var(--color-text-secondary); font-size: var(--font-size-body); }
.account-apply-box { margin-top: var(--space-4); border-color: var(--color-border-subtle); border-radius: var(--radius-card); }
.form-error { color: var(--color-danger); font-size: var(--font-size-caption); }

.starter-workbench, .workbench-card, .panel, .sidebar { border: 1px solid var(--color-border-default); border-radius: var(--radius-card); background: var(--color-surface-card); box-shadow: none; }
.starter-workbench, .workbench-card, .panel { padding: var(--space-4); }
.workbench-metrics { gap: var(--space-4); }
.workbench-card > span { color: var(--color-text-secondary); font-size: var(--font-size-caption); }
.workbench-card > strong { color: var(--color-text-primary); font-size: var(--font-size-metric); }
.todo-card-title { color: var(--color-text-primary) !important; }
.workbench-actions { gap: var(--space-2); }
.landlord-page-tabs { border-color: var(--color-border-subtle); background: var(--color-surface-card); box-shadow: none; }
.landlord-page-tab-list .tab { min-height: var(--control-height); color: var(--color-text-secondary); border-radius: var(--radius-control); }
.landlord-page-tab-list .tab.active { color: var(--color-brand-primary); background: var(--color-brand-soft); }

#landlordRoomsWorkspace { gap: var(--space-4); }
#landlordRoomsWorkspace .sidebar { padding: var(--space-4); }
#landlordRoomsWorkspace .section-title { margin-bottom: var(--space-3); }
#landlordRoomsWorkspace .section-title h2 { font-size: var(--font-size-section); }
#landlordRoomsWorkspace .room-list { gap: var(--space-2); }
#landlordRoomsWorkspace .room-item, #landlordRoomsWorkspace .room-card { border-color: var(--color-border-default); border-radius: var(--radius-card); }
#landlordRoomsWorkspace .room-item.active { border-color: var(--color-brand-primary); background: var(--color-brand-soft); }
#landlordRoomsWorkspace .content-grid { gap: var(--space-4); }
#landlordRoomsWorkspace .sidebar-room-form { gap: var(--space-3); }
#landlordRoomsWorkspace .room-create-mode { padding: var(--space-1); border-radius: var(--radius-control); background: var(--color-surface-disabled); }
#landlordRoomsWorkspace .room-create-mode button { border-radius: var(--radius-control); }

@keyframes ds-spin { to { transform: rotate(360deg); } }
@keyframes ds-pulse { 50% { opacity: .55; } }
@media (prefers-reduced-motion: reduce) { *, *::before, *::after { scroll-behavior: auto !important; animation-duration: .01ms !important; animation-iteration-count: 1 !important; transition-duration: .01ms !important; } }
@media (max-width: 720px) { .topbar { padding-inline: var(--space-4); } .workbench-metrics { grid-template-columns: 1fr; } .login-panel { padding: var(--space-5); } }