Yes, it is called Inline CSS, Here you styling the div
using some height, width, and background.
Here the example:
<div style="width:50px;height:50px;background color:red">
You can achieve same using Internal or External CSS
2.Internal CSS:
<head>
<style>
div {
height:50px;
width:50px;
background-color:red;
foreground-color:white;
}
</style>
</head>
<body>
<div></div>
</body>
3.External CSS:
<head>
<link rel="stylesheet" type="text/css" href="style.css">
</head>
<body>
<div></div>
</body>
style.css /external css file/
div {
height:50px;
width:50px;
background-color:red;
}