<body>
  <div id="container">
    <div id="green"></div>
    <div id="blue"></div>
    <div id="orange"></div>
    <div id="black"></div>
    <div id="yellow"></div>
    <div id="purple"></div>
 </div>
#container
{background-color:red;
width:100%;
height:100vh;
padding: 0;
margin: 0;
display:flex;
flex-flow: row wrap;
}

#green
{background-color:green;
width:20%;
height:20%;}

#blue
{background-color:blue;
width:20%;
height:20%;
}

#orange
{background-color:orange;
width:20%;
height:20%;}

#black
{background-color:black;
width:20%;
height:20%;}

#yellow
{background-color:yellow;
width:20%;
height:20%;}

#purple
{background-color:purple;
width:20%;
height:20%}

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.