body {
    margin: 0;
    font-family: Arial, sans-serif;
    background-image: url('galaxy.gif');
    background-repeat: repeat;
}

.contents {
    color: white;
    padding-top: 20px;
    padding-bottom: 20px;
    width: 960px;
    margin-top:-20px;
    margin-left: auto;
    margin-right: auto;
}

marquee {
    color: rgb(255, 255, 255);
    font-size: 38px;
    text-shadow:
        0 0 5px #ffffff,
        0 0 5px #ffffff,
        0 0 10px #ffffff,
        0 0 20px #ffffff;
}

header {
    padding-bottom: 10px;
    padding-left: 20px;
    background-color: #acacac70;
    height: 80px;
}
header h1 {
    font-family: "Georgia", "Times New Roman", "Yu Mincho", "YuMincho", "Hiragino Mincho ProN", "MS Mincho", serif;
    animation: neonGlow 2s infinite;
    color: rgb(255, 255, 255);
    font-size: 48px;
        text-shadow:
            0 0 5px #00ffea,
            0 0 15px #00ffea,
            0 0 30px #00ffea,
            0 0 50px #00ffea;
    margin: 0;
}

.container {
    color: rgb(0, 255, 255);
    display: flex;
    flex-wrap: wrap;
    padding-top: 3px;
    gap: 3px;
}

.containermain {
    padding-left: 10px;
    padding-right: 10px;
    background-color: #acacac70;
    width: 700px;
    height: 1200px;
}

.containerleft {
    padding-top: 20px;
    padding-left: 10px;
    padding-right: 10px;
    background-color: #acacac70;
    width: 257px;
    height: 1200px;
}
.containerleft a {
    color: rgb(255, 230, 0);
    text-decoration: none;
    font-weight: bold;
}
.containerleft a:hover {color: azure;}
.containerleft img {
 JHBHB 
}

footer {
    color: gray;
    padding: 10px;
}

* {
    box-sizing: border-box;
}

/* 以下JS併用 */

.mobile .contents {
    width: 100%;
    max-width: none;
    margin: 0;
}

.mobile .containermain {
    order: 2;
    flex: 0 0 100%;
    min-width: 0;
}
.mobile .containermain img {
    width: 100%;
    height: auto;
    display: block;
}

.mobile .containerleft {
    order: 1;
    width: auto;
    height: auto;       /* PC用の1200pxを解除 */
    flex: 1 1 0;
    min-width: 0;       /* 縮小制限を解除 */
}

.mobile .containerleft,
.mobile .containermain {
    overflow-wrap: break-word;
    word-break: break-word;
}

.mobile .containerleft{
    width:auto;
    flex:1;
}