Check out example codes for "css change background color of page". It will help you in understanding the concepts better.

Code Example 1

/* Use the following code: */
html {background-color: #fefefe;} 
/* You can change the hexedecimal code to RGB, RGBA, name & more colors!*/

Code Example 2

/* To apply color to background you have to use 'background-color' property and value of property is color name. */
html,body {
  background-color: blue;
}

Code Example 3

body {
  background-color: lightblue;
}

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