Hello,
Try to add this code in Custom CSS for desktop in Theme Options:
.single-product table.variations td {
display: inline-block;
vertical-align: middle;
margin-bottom: 0;
}
.single-product table.variations .label {
width: 20%;
margin-top: -10px;
}
.single-product table.variations .value {
width: 40%;
}
Regards,
Rose Tyler.