#page_header{
    background:url(../img/column/column-mv.webp?v=20250820) no-repeat center center; 
    background-size:cover;
}
#container{
    #blog_list{
        display: flex;
        flex-wrap: wrap;
    }
    #blog_list .item{
        height:auto;
    }
}
@media (max-width:800px) {
    #page_header{
        background-image:url(../img/column/column-mv-sp.webp?v=20250820); 
    }
}