The styling of the options table can be done by adding CSS to the front end CSS of HikaShop via the Display tab of the configuration.
On the demo website, it's that CSS which is used:
.hikashop_product_right_part{
background-color:#F5F5F5;
border:1px solid #ccc;
padding:5px;
}
.hikashop_product_options_table select{
border:1px solid #ccc;
margin-left:10px;
color:#666;}
.hikashop_option_name{
color:#167e93;
font-size:11px;}
.hikashop_option_name img{
margin-left:5px;}
#hikashop_product_left_part{
width:300px;
}
#hikashop_product_pice_with_options_main{
color:#14caec;
font-weight:bold;
border-top:1px solid #ccc;
border-bottom:1px solid #ccc;
text-align:center;
background-color:#fff;
padding:5px;
}
.hikashop_product_stock table{
margin-top:20px;}