[imaginem]

Hi,

edit style.css

Line 1962

class .sidebar-wrap, .sidebar-wrap-single

add

background: #colorhexvaluehere;
background: rgba(0,0,0,0.5);

For rgba 0,0,0, represents rgba color

0.5 at the end represents the opacity value. 1 for 100% , 0.5 is 50%

Thanks