Navigate to: C:\Users\<username>\AppData\Roaming\Mozilla\Firefox\Profiles\<profile id>.default\chrome\userChrome.css
If the file does not exist, create it (by creating a new .txt document and renaming it and saving with .css extension).
Right-click > Edit
If you just created the file, add this script at the top:
@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
1. To get rid of the dropdown button, add this script:
/*searchbar dropdown - remove */
.searchbar-dropmarker-image { max-width: 0 !important; opacity: 0 !important; }
Note: You will still be able to select and manage search engines by left clicking on the left side of the box, or on the icon.
Alternatively, if you want to also get rid of the icon use this script instead of the one above:
/*searchbar dropdown and icon - remove */
.searchbar-dropmarker-image, .searchbar-engine-image, .searchbar-engine-button {
max-width: !important; opacity: 0 !important; }
2. I couldn't get the bing.xml file to see the normal instructions for italics, maybe someone can point out how to do it here.
To change to search engine name text to italics, the best I can do for you is to make the text in the search box italic for everything:
Add this script to userChrome.css:
/*searchbar text - italic */
.searchbar-textbox { font-style: italic !important; }