Go to the Mozilla Add-ons Web Page {web Link} (There’s a lot of good stuff here) and search for what you want.

Thanks for the suggestion, but I've looked and there is no add-on for this!

I called for more help.

You can experiment with code like this in the userChrome.css file. Use suitable color for the #rrggbb property values. You can omit the color properties. If you do not use the !important flag then you get the usual hovering effects.

@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"); /* only needed once */

#PlacesToolbarItems > .bookmark-item[container] {font-weight: 600; padding-top: 5px !important}
#PlacesToolbarItems > .bookmark-item[container] {background-color: #f4f4ff;}

#PlacesToolbarItems > .bookmark-item[container][label="xx" i]       {background-color: #rrggbb; color: #rrggbb}
#PlacesToolbarItems > .bookmark-item:not([container])[label="xx" i] {background-color: #rrggbb; color: #rrggbb}

[label="xx] needs to be an exact match and [label="xx" i] means ignore case. You can use [label^="xx"] and [label*="xx"] for individual bookmarks with similar labels.

• https://developer.mozilla.org/en-US/docs/Web/CSS/Attribute_selectors

Thanks so much Cor-el! I'll give this a try and let you know how I got on. Thanks! :-)

Cor-el! THANK YOU! This script worked beautifully! This has made me SO HAPPY! Thank you! :-)

Not important, but I don't suppose you know a script for the rollover color? Or the folder icon color?

Also, the script you gave contained a line with "bookmark-item:not" - what does the "not" one do?

[container] means that the rule applies to a container (folder). not([container]) means that the rule applies to a normal bookmark (i.e. not a folder).

For rollover you can use the :hover pseudo class selector.

• https://developer.mozilla.org/en-US/docs/Web/CSS/:hover

#PlacesToolbarItems > .bookmark-item[container][label="xx"]:hover {...}

You probably need to use the !important flag to override existing rules.

• https://developer.mozilla.org/en-US/docs/Web/CSS/Specificity#The_!important_exception

on the same subject, how can i give a color to folders that i create on the bookmark bar ?