* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: "Microsoft Yahei", sans-serif;
}

body {
    background-color: #f5f7fa;
    padding: 70px 30px 40px;
}

/* 返回主页按钮 */
.home-btn {
    position: fixed;
    top: 25px;
    left: 25px;
    padding: 12px 26px;
    font-size: 18px;
    background: #2563eb;
    color: #fff;
    text-decoration: none;
    border-radius: 10px;
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.3);
    transition: all 0.25s ease;
    z-index: 99;
}
.home-btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 18px rgba(37, 99, 235, 0.45);
}

.page-title {
    text-align: center;
    font-size: 40px;
    color: #2d3748;
    margin-bottom: 50px;
}

/* 图层容器放大 */
.layer-box {
    max-width: 1400px;
    margin: 0 auto;
    background: #ffffff;
    padding: 45px;
    border-radius: 22px;
    box-shadow:
        0 2px 4px rgba(0,0,0,0.05),
        0 12px 30px rgba(0,0,0,0.12);
    transition: all 0.35s ease;
}
.layer-box:hover {
    transform: translateY(-8px);
    box-shadow:
        0 4px 8px rgba(0,0,0,0.06),
        0 20px 45px rgba(0,0,0,0.18);
}

/* 图片网格：最多3列，最后一行自动居中 */
.image-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
    justify-items: center;
}

.image-card {
    width: 100%;
    max-width: 340px;
    border-radius: 14px;
    overflow: hidden;
    border: 1px solid #e8e8e8;
    transition: all 0.3s ease;
    cursor: pointer;
}
.image-card:hover {
    transform: translateY(-6px);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.15);
}

.image-card img {
    width: 100%;
    height: 260px;
    object-fit: cover;
    display: block;
}

/* 弹窗遮罩 */
.preview-mask {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background: rgba(0, 0, 0, 0.85);
    display: none;
    justify-content: center;
    align-items: center;
    z-index: 9999;
    padding: 20px;
}

.preview-img {
    width: 75vw;
    height: 75vh;
    object-fit: contain;
    border-radius: 8px;
    transition: transform 0.15s ease;
    transform: scale(1);
}

.close-btn {
    position: absolute;
    top: 30px;
    right: 40px;
    font-size: 45px;
    color: #fff;
    cursor: pointer;
    user-select: none;
}

.arrow {
    position: absolute;
    font-size: 55px;
    color: #fff;
    cursor: pointer;
    user-select: none;
    padding: 0 25px;
}
.prev {
    left: 25px;
}
.next {
    right: 25px;
}