highlight_lines_in_two_columns.css

.two.column.diff .diff.line:not(.keep) .line.wrapper:not(.empty) .left.line.content {
  background-color: #FBDDDD;  /* rgba(91, 220, 114, 0.20) on white */
}
.two.column.diff .diff.line.base:not(.keep) .line.wrapper:not(.empty) .left.line.content,
.two.column.diff .diff.line.whitespace:not(.keep) .line.wrapper:not(.empty) .left.line.content {
  background-color: #FFF7F7;  /* rgba(91, 220, 114, 0.05) on white */
}

.two.column.diff .diff.line:not(.keep) .line.wrapper:not(.empty) .right.line.content {
  background-color: #DDF7E2;  /* rgba(91, 220, 114, 0.20) on white */
}
.two.column.diff .diff.line.base:not(.keep) .line.wrapper:not(.empty) .right.line.content,
.two.column.diff .diff.line.whitespace:not(.keep) .line.wrapper:not(.empty) .right.line.content {
  background-color: #EFFCF1;  /* rgba(91, 220, 114, 0.05) on white */
}

.two.column.diff .diff.line .left.line.content .delta {
  background-color: rgba(240, 92, 92, 0.30);
}
.two.column.diff .diff.line.base .left.line.content .delta,
.two.column.diff .diff.line.whitespace .left.line.content .delta {
  background-color: rgba(240, 92, 92, 0.15);
}

.two.column.diff .diff.line .right.line.content .delta {
  background-color: rgba(91, 220, 114, 0.30);
}
.two.column.diff .diff.line.base .right.line.content .delta,
.two.column.diff .diff.line.whitespace .right.line.content .delta {
  background-color: rgba(91, 220, 114, 0.15);
}