You have Firefox 26.

On Windows, you can switch between a compact two column menu accessed with an orange Firefox button, and the classic menu bar. This articles describes how to switch if you like: Display the Firefox button menu instead of the menu toolbar.

Is the problem of light green text on a website or in the interface? Usually it's a bad idea to change your whole approach to viewing websites just because of one bad site. Instead, there might be a quick way to "hack it." If you can post the address, I could give you some suggestions.

The problem site is Ameritrade.com. All throughout their site they have numbers and text displayed in thin bright green and it is hard for me to see them against the white background. I have corresponded with them about this and they say there is nothing I can do on the website and I should make the change on my computer. But I haven't been able to do that either, so I was looking for a way to change the brightness of the background on FF.

Thanks for your help.

Well, some mild hacking may be required if there isn't a better way. For example, you could create some custom style rules for the site. Because I don't have an account, I could only set up a few rules to address the publicly viewable pages. Maybe they will help once you are logged in as well. See the attached screen shots for comparison.

Here's how that was done (while viewing a page on the TD Ameritrade site):

(1) Install the Stylish extension: https://addons.mozilla.org/en-US/firefox/addon/stylish/

(2) Select and copy the following rules (all one block):

@namespace url(http://www.w3.org/1999/xhtml);
@-moz-document domain("tdameritrade.com") {
  /* Black links, and bold headlines */
  a:link, a:visited, header .alert .headline strong
  {
    color: #000 !important;
  }
  /* Black text and light backgrounds for header and footer */
  header .utility_nav-holder, footer .stock_footer, .stock_footer li
  {
    color: #000 !important;
    background-color: #eee !important; 
    background-image: none !important;
  }
}

(3) Stylish will add an "S" icon either to the main Navigation Toolbar or to the Add-on bar. Click the Stylish "S" icon > Write new style > Blank style.

(4) On line 1 of the larger box, paste in the block of rules.

(5) Click the Preview button to apply the rule. Success?

(6) Before saving the rule, type a name in the top box, for example: TD Ameritrade Colors

That's it. Unless there's a problem in Step 5.