Exported themes can't be installed (add-on is broken).
Firefox Color can't be synced without instalation.

I loved this theme for years — until now. When this gets fixed I'll give it 5 stars: it suddenly happened today that the webpage where you customize the colors is completely wonky. The entire page is in black & white, no color; the template is merely black broken outlines; the list is unworkable; and the color palette doesn't exist except for the hex numbers. Please please fix! Thank you.
MacBook Pro, OS Monterey 12.7.5

BROKEN - exported themes can't be installed - both .XPI and .ZIP - instalation says that add-on is broken. Tested many times, FF on Win 10 and Debian. Release and ESR. Please fix it - theme from FF Color can't be synced without instalation, the theme is broken on PC without straight source (non-synced doesn't work).

Tried to upload my Theme (Used the top bit of some old Destiny 1 Promo Art that was shades of blue with white specks) so others could use it, but it was removed in only 11 minutes for and I quote "Content, specifically Spam: This item has been identified as deceptive, high-volume commercial content which is not permitted by AMO."

There are plenty of other Themes that use Destiny as well as other game IPs. I only tried to upload one that I felt looked good that wasn't similar to any others that I could find and yet it didn't even last 11 minutes.

That said, the Extension itself is good and works well. Just don't try to upload anything for others to use apparently.

ruined my browsing experience, might have to go back to chrome because wtf is this??? don't know how to fix this glitch uninstalled app, uninstalled & reinstalled firefox...still the same

This add-on deserves minus stars. As other users state, you can't restore your old theme. This add-on is an absolute RUBBISH!

unable to add transparency to almost all items. this limits your custom imagery to a very limited area, minimizing the entire point of the exercize.

Functionally unusable if you just want to tweak the colors of the standard theme. If I change the color if a single thing, it changes the colors of everything to the stupid theme the add-on starts off with.

I had a custom theme saved & it still shows that it's there, but it won't actually allow it to be put on my screen. I HATE the preset ones as I can't see them well at all & some literally make me physically ill. I NEED to be able to keep the one that I have had for a long time that suddenly disappeared.

元に戻すにはどうすればいいのだ？

No option for old Firefox colors. Photon isn't it. I HAD designed my own and saved it - TWICE and Firefox took it down and reverted to gray again. IF IT AIN'T BROKE DON'T FIX IT. You could distinguish firefox from other browsers before, but not now. And the old designe isn't there. Again, Photon isn't it.

can't save custom backgrounds and have them synced across multiple devices. so dumb

Where do I find saved color sets? I see saved sets after only aafter I make changes & click save icon. But, if I come back later, I can find neither a tab/button, nor any info on how to save/retrieve them, except for exporting.

我喜欢

This is, as far as I can tell, completely useless. Managed to get it to display a custom image, eventually and more by fluke than anything. The tab for the saved "themes" is hidden by the text box on smaller screens so didn't even find it until by chance looking on another computer. The main reason I wanted to customise the theme was so I could distinguish between personal/work profiles, but the "theme" doesn't sync when using Firefox Sync so this is not only unusable but also useless. Do not see the point of this add-on.
Also, minor annoyance, from the settings page there is a link that has been localised to say "Firefox Colour" but it is still called "Firefox Color" everywhere else. Pointless localisation there, either do it everywhere or nowhere.

Causes conflicts with Firefox's themes. Only use one or the other.

I just wanted to change my top bar colour to blue and it's so complicated? Other colours randomly changed on other UI elements that I didn't ask for? Could you have made this any more baffling?
I was also turned off by Firefox marketing associating "blue" with "activist". Yeh no thanks pal, I just like the colour, save me the cod psychology...

I just wanted to change my top bar color to purple and it's so complicated to do. I have to recreate the whole default theme from scratch and then tweak the purple. When I got to a result I liked I saved the preset. After a while I wanted to change the shade a little bit. I did so but I was not satisfied, and by mistake I clicked reset all, instead of Back. At that point I was screwed, had no idea where to find the saved themes, would have had to recreate the original theme once again so I gave up, uninstalled the extension and came here to write this review. Work on your UX because this is really awful.