body {
    font-family: 'Microsoft YaHei', Arial, sans-serif; /* 设置字体为微软雅黑 */
    background-color: #f0f0f0;
    margin: 0;
    padding: 0;
    overflow: hidden; /* 防止页面滚动 */
    font-size: 16px; /* 调整全局字体大小 */
}
main {
    padding: 0;
    text-align: center;
    position: relative;
    height: 100vh; /* 使main元素的高度等于视口高度 */
    transition: opacity 0.5s ease-in-out; /* 添加过渡效果 */
}
main img {
    width: 100%;
    height: 100%;
    object-fit: cover; /* 确保图片覆盖整个main元素 */
}
.overlay {
    position: absolute;
    top: 50%; /* 初始位置在屏幕中间 */
    left: 50%;
    transform: translate(-50%, -50%) scale(0.5); /* 初始缩放 */
    color: white;
    font-size: 48px; /* 调整字体大小 */
    font-weight: bold;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.5);
    opacity: 0;
    animation: fadeInMoveUp 0.5s ease-out forwards; /* 调整动画持续时间 */
}
@keyframes fadeInMoveUp {
    0% {
        top: 50%;
        opacity: 0;
        transform: translate(-50%, -50%) scale(0.5); /* 初始缩放 */
    }
    100% {
        top: 40%; /* 最终位置 */
        opacity: 1;
        transform: translate(-50%, -50%) scale(1); /* 最终缩放 */
    }
}
.scroll-down {
    position: absolute;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
}
.scroll-down div {
    width: 0;
    height: 0;
    border-left: 10px solid transparent;
    border-right: 10px solid transparent;
    border-top: 5px solid white;
    margin: 3px 0;
    animation: bounce 3.5s infinite; /* 调整动画持续时间 */
}
.scroll-down div:nth-child(1) {
    opacity: 0.3;
}
.scroll-down div:nth-child(2) {
    opacity: 0.6;
}
.scroll-down div:nth-child(3) {
    opacity: 1;
}
@keyframes bounce {
    0%, 20%, 50%, 80%, 100% {
        transform: translateX(-50%) translateY(0);
    }
    40% {
        transform: translateX(-50%) translateY(-10px);
    }
    60% {
        transform: translateX(-50%) translateY(-5px);
    }
}
footer {
    background-color: #333;
    color: white;
    text-align: center;
    padding: 10px;
    position: fixed;
    width: 100%;
    bottom: 0;
    font-size: 16px; /* 调整页脚字体大小 */
}