How can i partially set the background color of a div tag using CSS.

Question

example if height of div element is 300px i want the background to fill up to 150px height.

Answer 1

try this
div{
background-color: blue;
background-size: 150px 300px;
}

yes for mix of two colours you have to use linear gradient

Answer 2

I don't actually think u can do that but I think u can use gradient
like upper half be blue
and lower half be the background color