.gallery-layout{
    display:grid;
    grid-template-columns: 2fr 1fr;
    grid-template-rows: 1fr 1fr;
    gap:12px;
    height:520px;
}

/* base */
.gallery-layout a{
    display:block;
    background-size:cover;
    background-position:center;
    border-radius:5px;
    overflow:hidden;
    position:relative;
}

/* layout posizioni */
.item-0{
    grid-row: 1 / span 2; /* grande sinistra */
}

.item-1{
    grid-column: 2;
    grid-row: 1;
}

.item-2{
    grid-column: 2;
    grid-row: 2;
}

/* nascondi resto */
.gallery-hidden{
    display:none;
}

/* overlay +N */
.gallery-more{
    position:absolute;
    inset:0;
    background:rgba(0,0,0,.45);
    color:#fff;
    display:flex;
    align-items:center;
    justify-content:center;
    font-size:28px;
    font-weight:600;
}

/* mobile */
@media (max-width:768px){
    .gallery-layout{
        grid-template-columns:1fr;
        grid-template-rows:repeat(3, 180px);
        height:auto;
    }

    .item-0,
    .item-1,
    .item-2{
        grid-column:auto;
        grid-row:auto;
    }
}