:root {
  --primary: #2563EB;
  --primary-dark: #1D4ED8;
  --primary-light: #DBEAFE;
  --bg: #F8FAFC;
  --card: #FFFFFF;
  --text: #1E293B;
  --text-muted: #64748B;
  --border: #E2E8F0;
  --sidebar-bg: #FFFFFF;
  --sidebar-active: #DBEAFE;
  --success: #16A34A;
  --warning: #F59E0B;
  --danger: #DC2626;
  --info: #0EA5E9;
  --shadow: 0 1px 3px rgba(0,0,0,0.08);
  --radius: 10px;
}
body { background: var(--bg); color: var(--text); font-family: 'Segoe UI', system-ui, sans-serif; }
.app-wrapper { display: flex; min-height: 100vh; }
.sidebar { width: 250px; background: var(--sidebar-bg); border-right: 1px solid var(--border); position: fixed; top: 0; left: 0; bottom: 0; overflow-y: auto; transition: transform .25s; z-index: 1040; }
.sidebar .brand { padding: 18px 20px; font-size: 1.2rem; font-weight: 700; color: var(--primary); border-bottom: 1px solid var(--border); }
.sidebar .nav-link { color: var(--text); padding: 11px 20px; display: flex; align-items: center; gap: 10px; border-radius: 8px; margin: 2px 10px; }
.sidebar .nav-link:hover { background: var(--bg); }
.sidebar .nav-link.active { background: var(--sidebar-active); color: var(--primary-dark); font-weight: 600; }
.main-area { flex: 1; margin-left: 250px; display: flex; flex-direction: column; }
.topbar { height: 60px; background: var(--card); border-bottom: 1px solid var(--border); display: flex; align-items: center; justify-content: space-between; padding: 0 20px; position: sticky; top: 0; z-index: 1030; }
.content { padding: 22px; flex: 1; }
.app-footer { padding: 14px 22px; border-top: 1px solid var(--border); color: var(--text-muted); font-size: .85rem; text-align: center; }
.card { background: var(--card); border: 1px solid var(--border); border-radius: var(--radius); box-shadow: var(--shadow); }
.btn-primary { background: var(--primary); border-color: var(--primary); }
.btn-primary:hover { background: var(--primary-dark); border-color: var(--primary-dark); }
.text-primary { color: var(--primary) !important; }
.sidebar-toggle { display: none; background: none; border: none; font-size: 1.5rem; color: var(--text); }
@media (max-width: 900px) {
  .sidebar { transform: translateX(-100%); }
  .sidebar.show { transform: translateX(0); }
  .main-area { margin-left: 0; }
  .sidebar-toggle { display: block; }
}