how to make a background color light in css code example

Example 1: css transparent background color

div {
 opacity:25% ; 
}

Example 2: css set background color

body {
	background-color: red; 
}

Example 3: background color

//javascript type css:
document.body.style.backgroundColor = "blue";
// or inline css:
<div style="background-color: blue;"></div>

Example 4: css coor background

body {background-color: coral;}