Add Different Margins to Each Side of an Element is not working why?

Tell us what’s happening:

Your code so far

<style>
  .injected-text {
    margin-bottom: -25px;
    text-align: center;
  }

  .box {
    border-style: solid;
    border-color: black;
    border-width: 5px;
    text-align: center;
  }

  .yellow-box {
    background-color: yellow;
    padding: 10px;
  }
  
  .red-box {
    background-color: red;
  margin-top:40px;
  margin-left:40px;
   margin-right:20px;
    margin-bottom:20px
    
  }

  .green-box {
    background-color: green;
    margin-top:40px
    margin-left:40px
    margin-right:20px
    margin-bottom:20px
  }
</style>
<h5 class="injected-text">margin</h5>

<div class="box yellow-box">
  <h5 class="box red-box">padding</h5>
  <h5 class="box green-box">padding</h5>
</div>

Your browser information:

Your Browser User Agent is: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/64.0.3282.119 Safari/537.36.

Link to the challenge:
https://www.freecodecamp.org/challenges/add-different-margins-to-each-side-of-an-element

-----these changed i made to the green box are not effective!please help

When you have multiple key-value pair each pair must end with a semicolon.Check for semicolons in .green-class.
Also note that the syntax highlighter shows up differently when the syntax is wrong giving you a clue of syntax errors