how to get my navigation button stay active

Can't get my navigation to stay active using html and css. It just light up but does not stay active when pressed. What am I missing?

How do I make it stay active when pressed? Really need the help fast! Sorry for my bad code, I'm new to coding.

How do I type the active class? I tried to, but it did not work.

HTML

<div id="apaknavig">
  <div id="menu2">
    <ul>
      <li><a href="uznemums.html">Uzņēmums</a></li>
      <li><a href="kontakti.html">kontakti</a></li>    
    </ul>
  </div>
</div>

CSS

#apaknavig {
  Width: 200px;
  height: 604px;
  top:-613px;
  position:relative;
  font:14px Arial;
  color:black;      
  float:left;
  right:35px;
  text-indent:12px;
  display: block;
  line-height:30px;
}

#menu2 ul{
  list-style:none;
  float: left;
  font:14px Arial;
  color:black;  
  right:90px;
  text-decoration:none;
  text-align:left; width:10px;
  display: block;
  line-height:30px;
  margin-bottom:10px;
}

#menu2 a{
  background-image: url(bildes/apak_navig.png);
  display:block;
  width: 196px;
  height:34px;
  font:14px Arial;
  color:black;  
  float:left;
  right:90px;
  text-decoration:none;
  display: block;
  line-height:30px;
  margin-bottom:3px;
}

#menu2 a:hover{
  background-image: url(bildes/apak_navig_green.png);
  color:white;
  font:14px Arial;
  color:black;  
  text-decoration:none;
  display: block;
  line-height:30px;
}

Just change #menu2 a:hover{ to #menu2 a:hover, #menu2 a:active {.

You just have to add #menu2 a:active to the CSS.

#menu2 a:hover,#menu2 a:active{
  background-image: url(bildes/apak_navig_green.png);
  color:white;
  font:14px Arial;
  color:black;  
  text-decoration:none;
  display: block;
  line-height:30px;
}

I tried it but it just does not work. It continues to just hover, but does not stay active when I press it.