<!DOCTYPE html>
<html>
<head>
<style>
table, th, td {
border: 1px solid black;
}
</style>
</head>
<body>
<h1>Add Background Color to th</h1>
<table>
<tr>
<th style="background-color:#FF0000">Month</th>
<th style="background-color:#00FF00">Savings</th>
</tr>
<tr>
<td>January</td>
<td>$100</td>
</tr>
</table>
</body>
</html>