@media screen and (max-width: 767px) {
     .site_logo {
         max-width: 300px;
         max-height: 300px;
    }
     .board_list {
         display: grid;
         justify-content: center;
    }
     .board_list_column:nth-child(1) {
         grid-column: 1 / span 2;
    }
     .board_list_column:nth-child(2) {
         grid-column: 1 / span 2;
    }
     .board_list_column:nth-child(3) {
         grid-column: 1 / span 1;
    }
     .board_list_column:nth-child(4) {
         grid-column: 2 / span 1;
    }
     .board_list_column:nth-child(5) {
         grid-column: 1 / span 2;
    }
}