.myimage img {
    display: block;
    margin: 20px auto 0 auto;
    max-width: 660px;
    height: auto;
    border: 1px solid #999; 
}

    /* 第二张图片的行间距加大*/
    .myimage img + img {
        margin-top: 50px;
    }


.lightbox {
    display: none;
    position: fixed;
    z-index: 9999;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    /* ⭐ 关键：居中 */
    display: none;
    justify-content: center;
    align-items: center;
    background-color: rgba(0,0,0,0.85);
}


/* 图片 */
.lightbox-content {
    display: block;
    margin: auto;
    max-width: 90%;
    max-height: 90%;
}

/* 关闭按钮 */
.lightbox-close {
    position: absolute;
    top: 20px;
    right: 35px;
    font-size: 40px;
    color: white;
    cursor: pointer;
}

/* 鼠标效果 */
.myimage img {
    cursor: zoom-in;
}