1. Backup your files before applying any modification.
2. Go to Appearance>>Editor
3. Select the “style.css” file in the right column.
4. Find
#header {
background: #fafafa;
min-height: 80px;
overflow: hidden;
width: 100%;
}
5. Replace background: #fafafa with the color of your choice.
6. If you want to change the navigation menu color too, find
#nav {
background-color: #fafafa;
clear: both;
color: #686868;
overflow: hidden;
text-transform: uppercase;
width: 100%;
}
7. Replace background-color: #fafafa with the color of your choice.