.lb {
    display: flex;
    position: fixed;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    justify-content: center;
    align-items: center;
    background: rgba(0,0,0,.7);
    opacity: 0;
    transition: .3s opacity ease;
    pointer-events: none;
    z-index: 100;
}

.lb img {
    width: auto !important;
    max-height: 100%!important;
    cursor: pointer;
}

.lb img,
.lb iframe {
    transform: scale(.85);
    transition: .3s all ease;
}

.lb:target {
    opacity: 1;
    pointer-events: auto;
    z-index: 101;
}

.lb:target img,
.lb:target iframe {
    transform: scale(1);
}

/* なんちゃって閉じるボタン*/
.lb::before,.lb::after {
    display: block;
    position: fixed;
    content: "";
    width: 24px;
    height:3px;
    top: 24px;
    right: 12px;
    background: #fff;
    border-radius: 4px;
}
.lb::before {
    transform: rotate(-315deg);
}
.lb::after {
    transform: rotate(315deg);
}