:root {
  --blue: #007bff;
  --gray: #f8f9fa;
  --dark: #343a40;
  --light: #ffffff;
  --sidebar-width: 220px;
}
* { margin: 0; padding: 0; box-sizing: border-box; font-family: Arial, sans-serif; }
body { display: flex; min-height: 100vh; }
.sidebar {
  width: var(--sidebar-width);
  background: var(--dark);
  color: var(--light);
  display: flex;
  flex-direction: column;
  padding: 20px 10px;
}
.sidebar h2 { color: var(--blue); margin-bottom: 30px; text-align: center; }
.sidebar a {
  color: var(--light);
  text-decoration: none;
  padding: 10px;
  display: flex;
  align-items: center;
  gap: 8px;
  border-radius: 4px;
  cursor: pointer;
}
.sidebar a i { font-size: 18px; }
.sidebar a:hover { background: var(--blue); }
.submenu {
  display: none;
  flex-direction: column;
  padding-left: 20px;
}
.submenu a {
  font-size: 14px;
  padding: 6px 10px;
  background: rgba(255,255,255,0.05);
}
.submenu a:hover {
  background: rgba(255,255,255,0.15);
}
.sidebar a.toggle::after {
  content: "\f140";
  font-family: 'Material Design Icons';
  margin-left: auto;
  transition: transform 0.3s;
}
.sidebar a.toggle.open::after {
  transform: rotate(90deg);
}
.main {
  flex: 1;
  display: flex;
  flex-direction: column;
}
header {
  background: var(--gray);
  padding: 10px 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-bottom: 1px solid #ccc;
}
header .title { font-weight: bold; font-size: 18px; }
header .profile { font-size: 14px; color: #555; }
.content {
  flex: 1;
  padding: 20px;
  background: #f4f4f4;
}
.card {
  background: #fff;
  padding: 20px;
  border-radius: 6px;
  box-shadow: 0 1px 3px rgba(0,0,0,0.1);
  margin-bottom: 20px;
}
footer {
  background: var(--gray);
  text-align: center;
  padding: 10px;
  font-size: 13px;
  color: #666;
}
form label { display: block; margin-bottom: 5px; }
form input, form button {
  width: 100%; padding: 8px; margin-bottom: 10px; border: 1px solid #ccc; border-radius: 4px;
}
form button { background: var(--blue); color: white; border: none; cursor: pointer; }
form button:hover { background: #0056b3; }
@media (max-width: 768px) {
  body { flex-direction: column; }
  .sidebar { width: 100%; flex-direction: row; overflow-x: auto; }
  .sidebar a { flex: 1; justify-content: center; }
}