creating a css class that effect multiple blocks in the same region of a fusion subtheme

creating a css class that effect multiple blocks in the same region of a fusion subtheme
hi i just started creating my first Drupal site using a custom fusion sub-theme. In the top-header region of my sub-theme i have two blocks, "the search bar" and the "user menu" however these bocks seem to add some unwanted margin bottom. I tried to fix this problem in my-styles.css folder by adding this.

#header-top .block {
margin: 0;
padding-top: 5px;
padding-bottom: 5px;
}

this fixed the margin_bottom in the search bar block, but when a user logs in the user menu block that appears in the top-header region regresses to it's original margin setting. I deducted that my css code for some reason is only effecting the search bar because when i move the user menu block to a different region my css code works for all pages, meaning my margin stays at zero.. any ideas on how i can apply this css code to both blocks in the same region?

thanks.