body{font:12px/1.511 Verdana, clean, sans-serif;background:#e2d2b9;}

div.twodays {
    display:grid;
    grid-template-columns:repeat(2, min-content);
    grid-column-gap:14em;
}
div textarea {
    font-size:0.9em;
    color:#448;
}

#day--1 {grid-column:1}
#day--2 {grid-column:2}

input { width:25px; }
a {
    color:blue;
    text-decoration:underline;
    font-size:1.1em;
    cursor:pointer;
}
td, button {cursor:pointer;}
td+td {  /* all except the first one */
    font-family:monospace;
    text-align:center;
    padding-right:2px;
}

.highlight {background:white;}

td.gap-source, td.gap-dest {
    background: yellow;
}

td:first-child { background:#F4F6F6 }
.toKeepStruc {background:LightBlue}