body {
    font-family: Arial, sans-serif;
    background-color: #f8f9fa;
}
.sidebar {
    background-color: white;
    height: 100vh;
    position: fixed;
    padding-top: 20px;
    box-shadow: 2px 0 5px rgba(0,0,0,0.1);
}
.sidebar a {
    color: #333;
    padding: 10px 15px;
    display: block;
    text-decoration: none;
    border-left: 3px solid transparent;
}
.sidebar a:hover {
    background-color: #f0f8ff;
    color: #007bff;
}
.sidebar a.active {
    background-color: #f0f8ff;
    color: #007bff;
    border-left: 3px solid #87ceeb;
    font-weight: bold;
}
.main-content {
    margin-left: 250px;
    padding: 20px;
    background-color: white;
    min-height: 100vh;
}
.section {
    margin-bottom: 30px;
    padding: 20px;
    border-radius: 5px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    border-top: 3px solid #87ceeb;
}
.example {
    background-color: #f0f8ff;
    padding: 10px;
    border-left: 4px solid #87ceeb;
    margin-top: 10px;
}
h1 {
    color: #007bff;
    border-bottom: 2px solid #87ceeb;
    padding-bottom: 10px;
    margin-bottom: 20px;
}
h2 {
    color: #4682b4;
    border-bottom: 1px solid #87ceeb;
    padding-bottom: 5px;
}
.grade-content {
    display: none;
}
.grade-content.active {
    display: block;
}
.grade-table {
    width: 100%;
    margin-bottom: 20px;
    border: 1px solid #87ceeb;
}
.grade-table th {
    background-color: #87ceeb;
    color: white;
    padding: 10px;
    text-align: center;
}
.grade-table td {
    padding: 8px;
    text-align: center;
    border-bottom: 1px solid #87ceeb;
}
.grade-table tr:nth-child(even) {
    background-color: #f0f8ff;
}
.card-header {
    background-color: #87ceeb !important;
    color: white !important;
}
@media (max-width: 768px) {
    .sidebar {
        width: 100%;
        height: auto;
        position: relative;
    }
    .main-content {
        margin-left: 0;
    }
}