TwentyFourteen is a popular theme for school websites.

One feature that some people dislike is the way the site is displayed on a wide screen left aligned. 

 

You can easily set the site to be entered like this if you like:

 

To do this you need to activate the Jetpack plugin and then the CSS module in Jetpack settings.

 

This will add an extra menu item to the Appearance section of your dashboard Edit CSS.

In that section you can add this snippet of CSS to

.site {
margin: 0 auto;
}

 

More information: Custom CSS – Jetpack