#app-shell { display: flex; min-height: 100vh; }

/* ===================== Sidebar ===================== */
#sidebar {
  width: var(--sidebar-width);
  flex-shrink: 0;
  background: var(--color-surface);
  border-right: 1px solid var(--color-border);
  display: flex;
  flex-direction: column;
  position: sticky;
  top: 0;
  height: 100vh;
  z-index: 50;
}
.sidebar-brand {
  display: flex; align-items: center; gap: 10px;
  padding: 18px 20px; height: var(--topbar-height);
  border-bottom: 1px solid var(--color-border);
  font-weight: 700; font-size: 15px;
}
.sidebar-brand .logo-dot {
  width: 10px; height: 10px; border-radius: 3px; background: var(--color-primary);
}
.sidebar-nav { flex: 1; overflow-y: auto; padding: 12px; }
.nav-link {
  display: flex; align-items: center; gap: 10px;
  padding: 10px 12px; border-radius: var(--radius-sm);
  color: var(--color-text-muted); font-weight: 600; font-size: 13.5px;
  cursor: pointer; margin-bottom: 2px;
}
.nav-link:hover { background: var(--color-surface-alt); color: var(--color-text); text-decoration: none; }
.nav-link.active { background: var(--color-primary-soft); color: var(--color-primary); }
.nav-link .nav-icon { width: 18px; text-align: center; }
.nav-section-label {
  font-size: 11px; text-transform: uppercase; letter-spacing: 0.05em;
  color: var(--color-text-muted); padding: 14px 12px 6px;
  font-weight: 700;
}

/* ===================== Topbar ===================== */
#topbar {
  height: var(--topbar-height);
  border-bottom: 1px solid var(--color-border);
  background: var(--color-surface);
  display: flex; align-items: center; justify-content: space-between;
  padding: 0 22px;
  position: sticky; top: 0; z-index: 40;
}
#topbar .page-title { font-size: 16px; font-weight: 700; }
.topbar-right { display: flex; align-items: center; gap: 14px; }
.user-chip {
  display: flex; align-items: center; gap: 8px;
  padding: 6px 12px; border-radius: 100px;
  background: var(--color-surface-alt); font-weight: 600; font-size: 13px;
}
.user-chip .role-dot { width: 7px; height: 7px; border-radius: 50%; background: var(--color-success); }
.theme-toggle {
  width: 36px; height: 36px; border-radius: 50%;
  border: 1px solid var(--color-border); background: var(--color-surface);
  cursor: pointer; display: flex; align-items: center; justify-content: center;
  font-size: 16px;
}

#main-content { flex: 1; min-width: 0; display: flex; flex-direction: column; }
.page-content { padding: 22px; flex: 1; }
.page-section { display: none; }
.page-section.active { display: block; }

/* Mobile nav toggle */
#nav-toggle { display: none; background: none; border: none; font-size: 20px; cursor: pointer; color: var(--color-text); }

@media (max-width: 960px) {
  #sidebar {
    position: fixed; left: 0; top: 0; transform: translateX(-100%);
    transition: transform 0.2s ease; box-shadow: var(--shadow-lg);
  }
  #sidebar.open { transform: translateX(0); }
  #nav-toggle { display: block; }
  .form-grid { grid-template-columns: 1fr; }
}

@media (max-width: 640px) {
  .page-content { padding: 14px; }
  #topbar { padding: 0 14px; }
  .stat-grid { grid-template-columns: 1fr; }
}