Learn CSS Colors by Building a Set of Colored Markers - Step 78

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Describe your issue in detail here.

Hello fellow coders,

I’m stuck on step 78 of the “Markers” CSS assignment, and I can’t figure out how to target two classes with one rule. All of the online examples I’ve found say the proper way to target two classes is: .cap.rule {display: inline-block;}, and I’ve tried it, but I keep getting the following response: " You should use a class selector to target both the cap and sleeve classes."
Your code so far

<!-- file: index.html -->
<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Colored Markers</title>
    <link rel="stylesheet" href="styles.css">
  </head>
  <body>
    <h1>CSS Color Markers</h1>
    <div class="container">
      <div class="marker red">
        <div class="cap"></div>
        <div class="sleeve"></div>
      </div>
      <div class="marker green">
      </div>
      <div class="marker blue">
      </div>
    </div>
  </body>
</html>
/* file: styles.css */
h1 {
  text-align: center;
}

.container {
  background-color: rgb(255, 255, 255);
  padding: 10px 0;
}

.marker {
  width: 200px;
  height: 25px;
  margin: 10px auto;
}

.cap {
  width: 60px;
  height: 25px;
}

.sleeve {
  width: 110px;
  height: 25px;
  background-color: rgba(255, 255, 255, 0.5);
}


/* User Editable Region */

 .cap.sleeve {display: inline-block;}

/* User Editable Region */


.red {
  background: linear-gradient(rgb(122, 74, 14), rgb(245, 62, 113), rgb(162, 27, 27));
}

.green {
  background: linear-gradient(#55680D, #71F53E, #116C31);
}

.blue {
  background: linear-gradient(hsl(186, 76%, 16%), hsl(223, 90%, 60%), hsl(240, 56%, 42%));
}

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Challenge: Learn CSS Colors by Building a Set of Colored Markers - Step 78

Link to the challenge:

If you have to add two or more classes to the multiple elements selector, follow the rule:

.class1, class2, .class3 {
  property: value;
}

Thank you. None of the examples I found online used commas. Is that common or does using one class selector for multiple classes always require the use of commas?

If you are using multiple classes in a style then they must be separated by a comma