.block { display:flex; gap:16px; align-items:flex-start; }
/*.block img { height:auto; width:auto; }*/
.block .down{ 
      margin-top: 24px; /* この1枚だけ下に */
}

.block .column {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

hr { max-width:768px; margin:7px 0; }

.scheme {
    display: block; 
    margin-left: 0; 
    margin-right: auto;
}
.scheme img {
    display: block; 
    margin-bottom: 7px; 
}
.scheme .caption {
    font-size: 13px;
    font-weight: bold;
    color: "#666666";
}