Please go to templates/sj_hexagon/css/template-emerald.css find code:
.pager li > a, .pager li > span {
background: #eee none repeat scroll 0 0;
border-radius: 0;
}
=> edit to:

.pager li > a, .pager li > span {
background: #eee none repeat scroll 0 0;
border-radius: 0;
width: 70px;
}