Use em to set font size

Example analysis:

In CSS, em is a very useful unit because it can automatically adapt to the font used by the user.

Set the font size using em units to resize text in all browsers. Unfortunately, it's still an IE problem. When you resize text, it will appear larger or smaller than normal.

The default text size in the browser is 16px; however, 1em is equal to the default text size.

You can convert pixels to em through the following formula:

●　px/16=em