* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: #f0f2f5;
}

.dashboard {
    display: flex;
    min-height: 100vh;
}

.sidebar {
    width: 260px;
    background: #2c3e50;
    color: white;
    padding: 20px;
}

.sidebar h3 {
    margin-bottom: 20px;
    text-align: center;
}

.sidebar ul {
    list-style: none;
}

.sidebar li {
    margin-bottom: 10px;
}

.sidebar a {
    color: white;
    text-decoration: none;
    display: block;
    padding: 10px;
    border-radius: 5px;
}

.sidebar a:hover {
    background: #34495e;
}

.main-content {
    flex: 1;
    padding: 20px;
}

.header {
    background: white;
    padding: 20px;
    border-radius: 10px;
    margin-bottom: 20px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.stat-card {
    background: white;
    padding: 20px;
    border-radius: 10px;
    text-align: center;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

.stat-card h3 {
    font-size: 32px;
    color: #27ae60;
}

.data-table {
    width: 100%;
    background: white;
    border-radius: 10px;
    overflow: hidden;
    margin-top: 20px;
}

.data-table th {
    background: #34495e;
    color: white;
    padding: 12px;
    text-align: left;
}

.data-table td {
    padding: 10px;
    border-bottom: 1px solid #ddd;
}

.data-table tr:hover {
    background: #f5f5f5;
}

.btn-primary, .btn-success, .btn-danger, .btn-warning {
    padding: 10px 20px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    text-decoration: none;
    display: inline-block;
    margin: 5px;
}

.btn-primary { background: #3498db; color: white; }
.btn-success { background: #27ae60; color: white; }
.btn-danger { background: #e74c3c; color: white; }
.btn-warning { background: #f39c12; color: white; }

.form-container {
    background: white;
    padding: 20px;
    border-radius: 10px;
    margin: 20px 0;
}

.form-container input, .form-container textarea, .form-container select {
    width: 100%;
    padding: 10px;
    margin: 10px 0;
    border: 1px solid #ddd;
    border-radius: 5px;
}

.login-container {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
}

.login-box {
    background: white;
    padding: 40px;
    border-radius: 10px;
    width: 350px;
    text-align: center;
}

.login-box input {
    width: 100%;
    padding: 10px;
    margin: 10px 0;
    border: 1px solid #ddd;
    border-radius: 5px;
}

.error {
    color: red;
    margin: 10px 0;
}

.alert-warning {
    background: #fff3cd;
    border: 1px solid #ffeeba;
    color: #856404;
    padding: 15px;
    border-radius: 5px;
    margin-bottom: 20px;
}

.exam-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 20px;
    margin: 20px 0;
}

.exam-card {
    background: white;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}