Please inquire at theme support page: http://wordpress.org/support/theme/evolve
That said, looks like this is making the sidebar wider:
.aside {
min-width: 320px;
width: 34%; <====this is the culprit
}
on line 58 of index (are you using a custom CSS theme option or plugin?)
try:
.aside {
min-width: 320px; <==this could be edited but each widgets content also
width: 34%; <==remove this line helps
}
There are also responsive layout @ media items:
@media screen and (max-width: 990px)
.aside {
width: 232px;
}
etc to be dealt with – consult the theme dev.