Check out example codes for "multiple color background". It will help you in understanding the concepts better.

Code Example 1

body{
/* Its, very important to set the background repeat to: no-repeat */
background-repeat:no-repeat; 

background-image:  
/* 1) An image              */ url(http://lorempixel.com/640/100/nature/John3-16/), 
/* 2) Gradient              */ linear-gradient(to right, RGB(0, 0, 0), RGB(255, 255, 255)), 
/* 3) Color(using gradient) */ linear-gradient(to right, RGB(110, 175, 233), RGB(110, 175, 233));

background-position:
/* 1) Image position        */ 0 0, 
/* 2) Gradient position     */ 0 100px,
/* 3) Color position        */ 0 130px;

background-size:  
/* 1) Image size            */ 640px 100px,
/* 2) Gradient size         */ 100% 30px, 
/* 3) Color size            */ 100% 30px;
}

Code Example 2

background: linear-gradient(<angle>, color1 color1-stop-at, color2 color2-start-at);

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