how to change the size of h1 in html code example

Example 1: css h sizes

h1  =>    32px    (2em)
h2  =>    24px  (1.5em)
h3  =>  20.8px  (1.3em)
h4  =>    16px    (1em)
h5  =>  12.8px  (0.8em)
h6  =>  11.2px  (0.7em)

Example 2: change font size of h1 in html

<style>
h1 { 
	font-size: 100px;
   }
</style>