body {
    background-color: #f8f9fa;
    position: relative;
    padding-top: 160px; /* 为header留出空间 */
    padding-bottom: 60px; /* 为footer留出空间 */
}
.header-bg {
    background: linear-gradient(rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0.5)), url('../images/campus-bg.jpg') no-repeat center center;
    background-size: cover;
    color: white;
    padding: 40px 0;
    position: fixed;
    top: 0;
    width: 100%;
    height: 160px; /* 添加固定高度 */
    z-index: 1000;
    box-shadow: 0 2px 10px rgba(0,0,0,0.2);
    display: flex;
    align-items: center;
}

.header-title {
    font-size: 2.8rem;
    font-weight: bold;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.5);
    margin-bottom: 0;
    width: 100%; /* 确保标题占据全部宽度 */
}

.sidebar {
    position: sticky;
    top: 160px; /* header高度 */
    height: calc(100vh - 220px); /* 减去header和footer高度 */
    overflow-y: auto;
    background-color: #fff;
    border-radius: 5px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}
.sidebar-item {
    padding: 12px 20px;
    border-bottom: 1px solid #eee;
    cursor: pointer;
    transition: all 0.3s;
    font-size: 1.1rem;
}
.sidebar-item:hover {
    background-color: #f0f0f0;
}
.sidebar-item.active {
    background-color: #0056b3;
    color: white;
}
.content {
    background-color: #fff;
    border-radius: 5px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    padding: 25px;
    margin-bottom: 20px;
    margin-top: 20px;
}
.platform-card {
    margin-bottom: 25px;
    border: 1px solid #dee2e6;
    border-radius: 5px;
    padding: 20px;
    transition: all 0.3s;
}
.platform-card:hover {
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
    transform: translateY(-3px);
}
.platform-name {
    color: #0056b3;
    cursor: pointer;
    font-weight: bold;
    font-size: 1.2rem;
    margin-bottom: 10px;
}
.platform-name:hover {
    text-decoration: underline;
}
.platform-desc {
    margin-top: 10px;
    color: #495057;
    line-height: 1.6;
}
.college-title {
    margin-top: 40px;
    padding-bottom: 12px;
    border-bottom: 2px solid #0056b3;
    color: #0056b3;
    font-weight: bold;
    scroll-margin-top: 180px; /* 确保标题不会被header遮挡 */
}
.no-url {
    color: #6c757d;
    cursor: default;
}
.footer {
    background-color: #343a40;
    color: white;
    text-align: center;
    padding: 20px 0;
    position: fixed;
    bottom: 0;
    width: 100%;
}
.footer p {
    margin: 0;
    font-size: 1rem;
}
@media (max-width: 768px) {
    .header-title {
        font-size: 1.8rem;
    }
    .sidebar {
        height: auto;
        margin-bottom: 20px;
        position: relative;
        top: 0;
    }
    .footer {
        position: relative;
    }
    body {
        padding-top: 140px;
        padding-bottom: 0;
    }
    .college-title {
        scroll-margin-top: 160px;
    }
}