1) I need to change background color of right sidebar
change this css
.col-3cm .main {
background: rgba(0, 0, 0, 0) url("../img/sidebar/s-right-s2.png") repeat-y scroll right 0;
}
2) You may also like for need find this text on your theme files
2) Solved
1) where can I find this css? Kind of beginner, sorry
wp-content/themes/hueman/assets/front/css/main.min.css
find .col-3cm .main