slight overlay css code example
Example 1: overlay color on image css
footer#site-footer{
position:relative;
}
footer#site-footer:before { /* use before property (pseudo-element) */
position: absolute;
content: '';
top: 0;
left: 0;
width: 100%;
height: 100%;
background: rgba(0,0,0,0.3);
}
Example 2: div color overlay css
box-shadow: inset 0 0 0 2000px rgb(0 0 0 / 67%);