Dear Hoang Chu,
1.
- please go to Administrator => Menu Manager: Edit Menu Item "Home" => Advanced Options => Link Type Options => Link Image => select your image
- go to your_site/templates/sj_expo/menusys/class/common/css/menustyle.css and the code below at the end of this file:
ul.navi li.level1.first > .item-link .menu-title{display:none;}
2.
- go to your_site/templates/sj_expo/menusys/class/common/css/menustyle.css and find:
ul.navi ul.subnavi {background-color: #b5b5b5;padding: 0 0 20px;}
=> change: "background-color: #b5b5b5;" to "background-color: your_color;"
- go to your_site/templates/sj_expo/menusys/class/common/css/megamenu.css and find:
ul.navi div.level2.mega-content{background: #b5b5b5;}
=> change: "background: #b5b5b5;" to "background: your_color;"
Thanks!