body {
    margin: 0;
    font-family: Arial, sans-serif;
    display: flex;
}

footer {
    width: 100%;
    background-color: #f4f4f4; /* 可根据需要调整颜色 */
    text-align: center;
    padding: 10px 0;
    position: fixed; /* 如果需要固定在页面底部 */
    bottom: 0;
}

.sidebar {
    width: 20%;
    background-color: #f4f4f4;
    padding: 20px;
    box-sizing: border-box;
}

.sidebar h1 {
    font-size: 24px;
    color: #0073e6;
}

.sidebar nav ul {
    list-style-type: none;
    padding: 0;
}

.sidebar nav ul li {
    position: relative;
    list-style: none;
    padding: 10px;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

.sidebar nav ul li::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.1);
    opacity: 0;
    transition: opacity 0.3s ease;
    pointer-events: none;
}

.sidebar nav ul li:hover::after {
    opacity: 1;
}

.gallery {
    width: 80%;
    display: flex;
    flex-wrap: wrap;
    padding: 10px;
    box-sizing: border-box;
}

.gallery img {
    width: 48%;
    margin: 1%;
    box-sizing: border-box;
}