title: Why the button change is frame color when i click on it?
body: <p>I create a button, but have a problem.
  When i click the button the frame color change and i don't understand why.
  I upload image before and after clicked.</p>
  
  <p>Before:
  <a href="https://i.stack.imgur.com/5jpB1.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/5jpB1.png" alt="enter image description here"></a></p>
  
  <p>After:
  <a href="https://i.stack.imgur.com/njygq.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/njygq.png" alt="enter image description here"></a></p>
  
  <p>Button css:</p>
  
  <pre><code>.aproveBtn
    background: $add-button
    background-image: -webkit-linear-gradient(top, $add-button, $add-button)
    background-image: -moz-linear-gradient(top, $add-button, $add-button)
    background-image: -ms-linear-gradient(top, $add-button, $add-button)
    background-image: -o-linear-gradient(top, $add-button, $add-button)
    background-image: linear-gradient(to bottom, $add-button, $add-button)
    -webkit-border-radius: 4px
    -moz-border-radius: 4px
    border-radius: 4px
    font-family: Arial
    color: #ffffff
    @include font-size(20)
    padding: 0px 35px 2px 36px
    text-decoration: none
  </code></pre>
  
  <p>Thanks</p>