body {
    margin: 0;
    padding: 0;
    height: 100vh;
    min-height: 150vh; 
    display: flex;
    justify-content: center;
    align-items: center;
    background-size: cover;
    background-repeat: no-repeat; /* 防止背景重复 */
    background-position: top center;
    font-family: Arial, sans-serif;
    color: white;
    text-shadow: 0 2px 5px rgba(0, 0, 0, 0.7);
}


footer {
    position: absolute;
    top: 1650px;
    left: auto;
    width: 100%;
    color: #ffffff;
    text-align: center;
    padding: 10px 0;
    font-size: 14px;
}

.content {
    text-align: center;
}

.title {
    font-size: 3em;
    font-weight: bold;
    margin: 0;
    opacity: 0; /* 初始隐藏 */
    transform: scale(0.5); /* 初始缩小 */
    transition: all 0.5s ease-out; /* 添加过渡效果 */
}

.title.show {
    opacity: 1; /* 显现 */
    transform: scale(1); /* 回归正常大小 */
}

.hidden {
    visibility: hidden; /* 页面加载前暂时隐藏，避免闪烁 */
}