if you haven’t notice Google Adsense font sizer are bigger this is because google ads unit are default to medium to give publishers control on their adsense units.
Here is a little instruction for you to take control of this changes.
How to make a default font size applicable to all ad units
1. Log in to your Google Adsense account and go to My Account > Account Settings.
2. You will see the Ad Display Preference options. Choose from the drop-down menu the default font size you want to use on your ad units.
3. Click Save Changes.
How to edit the font size of an existing ad unit
1. Log in to your Google Adsense account and go to Adsense Setup > Manage Ads.
2. Look for the ad unit you want to edit and click the corresponding …