Font Size in Sidebox All Wrong, No Matter What!

Recently I went to my website and noticed that the font size in all the sideboxes was suddenly bigger. I'm not sure how that happened, but the font actually extends beyond the box.

When I went in to the actual files to try and alter it, I received this message at the admin home, "Warning: Cannot modify header information - headers already sent by (output started at /home/heebe0/public_html/admin/includes/languages/english/index.php:74) in /home/heebe0/public_html/admin/includes/init_includes/init_templates.php on line 36."

I'm not the most advanced webmaster, but hopefully someone here is able to simply glance and say, "Well duh! All you have to do is...."

Thank you so much for any help!

https://www.heebeegeebeez.com

Zen Cart 1.3.8a
Database Patch Level: 1.3.8

My site has not been upgraded since initial install.

I've added Image Handler 2 and Easy Populate.

In your stylesheet (includes/templates/darkness/css/stylesheet.css), locate

.sideBoxContent {
	background-color: #383E44;
	padding: 0.4em;
	}

and add the line in red

.sideBoxContent {
	background-color: #383E44;
	padding: 0.4em;
	font-size: 0.7em;
	}

Adjust the size as needed.

The main page is fixed! Yay! But...as with so many solutions, a new problem reared it's head in response.

Now when I click on any of the links in the sideboxes...for example, "This Week's Comics" the boxes are reaaaaally tiny on the corresponding page. Is there any way to fix that?

Thank you so much for your help - I never would have came to tha ton my own!