:root {
  --sidebar-width: 260px;
}
#sidebar {
  width: var(--sidebar-width);
  min-height: 100vh;
  position: sticky;
  top: 0;
}
#main {
  min-height: 100vh;
  background: linear-gradient(180deg, #f8fafc 0%, #eef2f7 100%);
}
.card-hero {
  border: none;
  border-radius: 1rem;
  box-shadow: 0 10px 25px rgba(0,0,0,0.06);
}
.stat {
  border-radius: 1rem;
  box-shadow: 0 6px 16px rgba(0,0,0,0.05);
}