So for tags that worked fine in 7.5.8, I now have to add special css elements to get them to keep working?
Yes, it's so that you can format the tags so that they will display the same in every browser, versus using the base that X browser chose to use.
Keep in mind that there are some elements in the common.css which set some tags to basically be plain text, so that you can display the elements the same in all browsers
Quoting
http://sixrevisions.com/css/css-reset-stylesheets/Reset CSS either nullifies a default CSS property by setting it to 0, or it sets the property to a common-sense value (e.g., line-height: 1 on the element). Explicitly declaring certain CSS property values can help reduce inconsistencies in the way our HTML elements are rendered by the browser.