Problem with :Adjust the Hue of a Color

Tell us what’s happening:

What’s wrong with the cyan div tag please? HSM for cyan is hsl(180, 100%, 50%), which is what I coded, and still FCC tells me I’m wrong.

Your code so far

  body {
    background-color: #FFFFFF;
  .green {
    background-color: hsl(120, 100%, 50%);
    saturation: 100%;
  .cyan {
    background-color: hsl(180, 100%, 50%);
    saturation: 100%;
  .blue {
    background-color: hsl(240, 100%, 50%);
    saturation: 100%;
  div {
    display: inline-block;
    height: 100px;
    width: 100px;
<div class="green"></div>
<div class="cyan"></div>
<div class="blue"></div>

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:52.0) Gecko/20100101 Firefox/52.0.

Link to the challenge:

Your code looks correct (except that there are no saturation and Lightness properties in CSS). Have you tried in a different browser? Perhaps upgrading your Firefox might help

I have Firefox ESR 52.8.1 (latest ESR version)

I can’t use another Firefox since I am at work…

So FCC system does bug according to the browser version??What should I do? I will try with Internet Explorer 11, which is the only other available browser I have at work…

Ok. I think I know what’s wrong. It’s my workplace Web proxy that filters the FCC website…It does not work at 100%. I just tried to load the same URL on Internet Explorer 11 and only one part works…

that sucks…I don’t understand how therse prowies work: theyr should either block completely the Web page or allow it ocmpletely, but its in the middle…Illogical…

Is FF 100% compatible with Firefox ESR please??My office Network team just confirmed that they fully authorized the FCC website to run in our network…

I’m not sure how about the compatibility with the ESR release, sorry. @QuincyLarson @raisedadead please clarify, I don’t know who else to ask

It looks like it’s a quirk of how ESR computes a color in HSL. I tried the exercise in ESR and found that the cyan color is computed as rgb(0, 255, 254), while in the latest version it is computed as rgb(0,255,255). The exercise is looking precisely for this color value.

I can confirm that the problem comes from Firefox ESR because i just tried with Vivaldi browser and it works fine!! Sould I alert Mozilla team about this bug or should FCC take care of it?

Probably tell the Mozilla team, since it’s this particular release that’s behaving differently.

I’ll make an issue in the fcc repo, just in case

Hi @Theoask thanks a lot for reaching out and sorry about the delay in getting back you you.

Now coming to the limitations with the browsers. I understand that you are limited by work to use only Internet Explorer 11 or Firefox ESR

Now, both of these are enterprise edition browsers, meaning they are typically released once or twice a year by their makers and have features which are hence considered “very very stable for enterprise use”.

Unfortunately this also means that sometimes new features do not reach them which may be available to general public over other “normally stable but newer editions” of browsers. These are updated typically every couple months.

This means its unlikely that your bug report will be addressed soon, as long as it works in a stable version of Firefox (which is newer) and fails in Firefox ESR. This is because the updates will trickle down to ESR as and when the release cycles permit. Typically twice a year.