body, html {
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100%;
    overflow: hidden;
    font-family: 'Arial', sans-serif;
}

#main-container {
    position: relative;
    width: 100%;
    height: 100%;
}

/* 其他样式保持不变 */

#main-image {
    position: absolute;
    width: 100%;
    height: 100%;
    overflow: hidden;
}

.image-slide {
    background-size: cover;
    background-position: center;
    position: absolute;
    width: 100%;
    height: 100%;
    transition: opacity 1.5s; /* 渐变时间设置为1.5秒 */
    opacity: 0; /* 初始不透明度为0 */
}

.image-slide.active {
    opacity: 1; /* 活动幻灯片的不透明度为1 */
}

#overlay {
    background: rgba(0, 0, 0, 0.5);
    position: absolute;
    width: 100%;
    height: 100%;
    z-index: 1;
}

#message {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
    font-size: 2em;
    color: #ffffff;
    text-shadow: 2px 2px 8px rgba(0, 0, 0, 0.75);
    font-weight: bold;
    border: 4px solid #FFD700;
    padding: 20px;
    background-color: rgba(255, 215, 0, 0.3);
    border-radius: 10px;
    box-shadow: 0 0 20px rgba(255, 215, 0, 0.7);
    z-index: 2;
    line-height: 1.5;
}

/* 其他样式保持不变 */