theme table overlaps to the right! HELP!!!

THe theme table class is i think sticky-enabled sticky-table is overlapping the right blocks

how to fix this?

I tried everything

table.sticky-enabled {
width:500px;
border-collapse:collapse;
}

#system-themes-form {
width:500px;
border-collapse:collapse;
}

table.sticky-enabled sticky-table {
width:500px;
border-collapse:collapse;

}

table.sticky-enabled .sticky-table {
width:500px;
border-collapse:collapse;
}

nothing works