:root {
  --sidebar-width: 260px;
  --bg: #f4f7fb;
  --card: #ffffff;
  --text: #0f172a;
  --muted: #64748b;
  --primary: #2563eb;
  --border: #e2e8f0;
}
body { background: var(--bg); color: var(--text); font-family: Inter, system-ui, sans-serif; }
.login-page { background: linear-gradient(135deg, #eef4ff 0%, #f8fbff 100%); }
.login-card { width: 100%; max-width: 420px; border-radius: 20px; }
.admin-layout { display: flex; min-height: 100vh; }
.sidebar { width: var(--sidebar-width); min-height: 100vh; position: sticky; top: 0; }
.content-area { flex: 1; min-width: 0; }
.stat-card { border: 0; box-shadow: 0 8px 24px rgba(15, 23, 42, 0.06); border-radius: 18px; }
.editor-layout .content-area { display: flex; flex-direction: column; height: 100vh; overflow: hidden; }
.editor-shell { display: grid; grid-template-columns: 1fr 360px; height: calc(100vh - 73px); }
.canvas-wrapper { position: relative; overflow: auto; background: #eef2ff; }
.canvas-toolbar { position: absolute; top: 16px; right: 16px; z-index: 10; display: flex; gap: 8px; }
.concept-canvas { position: relative; width: 1800px; height: 1200px; background-image: radial-gradient(#cbd5e1 1px, transparent 1px); background-size: 24px 24px; }
.concept-node { position: absolute; border: 1px solid var(--border); border-radius: 16px; box-shadow: 0 10px 30px rgba(15,23,42,.10); padding: 16px; cursor: move; }
.properties-panel { overflow-y: auto; }
@media (max-width: 991.98px) {
  .sidebar { width: 84px; }
  .sidebar .nav-link { font-size: 0; }
  .sidebar .nav-link i { font-size: 1.2rem; }
  .editor-shell { grid-template-columns: 1fr; }
  .properties-panel { border-top: 1px solid var(--border); border-left: 0 !important; }
}