body { font-family: Arial, sans-serif; margin: 0; background-color: #f4f7f6; }
.sidebar { width: 250px; height: 100vh; background-color: #1a2542; position: fixed; color: white; padding-top: 20px; }
.sidebar a { display: block; padding: 15px; color: white; text-decoration: none; border-bottom: 1px solid #2c3e50; }
.sidebar a:hover { background-color: #2c3e50; }
.main-content { margin-left: 250px; padding: 20px; }
.stats-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
.card { background: white; padding: 20px; border-radius: 5px; box-shadow: 0 2px 5px rgba(0,0,0,0.1); }
.alert { border-left: 5px solid #e74c3c; }