So, I just working with HTML/CSS a bit and I hit a bit of a spacing dilemma. Here is my code.
HTML:
<!DOCTYPE html> 
<html> 
<head> 
<title>Tic Tac Toe Demo</title> 
<link rel='stylesheet' type='text/css' href='styles/styles.css'>
</head> 
<body>
<div id='container'>
    <div></div>
    <div></div>
    <div></div>
    <div></div>
    <div></div>
    <div></div>
    <div></div>
    <div></div>
    <div></div>
</div> 
</body> 
</html>
CSS:
body{
    background-color: grey;
    height: 1080px;
    width: 50%;
    margin: 0 auto;
}
#container{
    height: 100%;
    width: 100%;
    background-color: white;
}
div div{
    display: inline-block;
    background-color: grey;
    height: 25%;
    width: 25%;
    margin: 5px;
}
I have tested in Chrome and Firefox. I want the blocks in the container to fill the space however you can see that there is a white space. And I cannot figure out why this is. I have been able to manipulate it but I would rather learn the best practices way of correcting this instead of my ADHOC approach.