background color css

body {
  background-color: green;
}body {
  background-color: rgb(255,255,255);
}html,body {
  background-color: red;
}div {
 opacity:25% ; 
}body {
  background-color: lightblue;
}
 /* To apply color to background you have to use 'background-color' property and value of property is color name. */
html,body {
  background-color: blue;
}