CSS3 animate slide/hide navigation to influence other elements

Question

I would like to have a smooth animated transition of 1 & 2, when 1 is triggered to display. I have accomplished this here: http://codepen.io/jacksonbeale/pen/epjcs using a negative top margin, but the problem is that the height of 1 will vary depending on the number of items in the navigation, so this will not work for me.

nav {
    margin-top:-95px;
    width:100%;
    box-sizing:border-box;
    z-index:5;
    -webkit-transition: all 1s ease-in-out;
    -moz-transition: all 1s ease-in-out;
    -o-transition: all 1s ease-in-out;
    transition: all 1s ease-in-out;
    &.showmenu {
      margin-top:0;
    }
  }

My current project does not allow me to use jQuery, and any js needs to be written by another developer. I only have control over html & css. I seem to be running in to this issue a bit so it would be great if someone could offer a suggestion on a pure css method to accomplish what I need.

Answer 1

You could do this :

• Add a container around the menu and the content
• Position your content absolutely
• Then, as the container only has the height of the menu (content is out of flow with position:absolute;) you can use translateY to togggle the menu in and out with translateY(-100%)/translateY(0)

DEMO

HTML :

<div class="test">
  <div><span class="menulink">Menu</span></div>
  <div class="content">
    <nav>
      <ul>
        <li>One</li>
        <li>Two</li>
        <li>Three</li>
        <li>Three</li>
        <li>One</li>
        <li>Two</li>
        <li>Three</li>
        <li>Three</li>
      </ul>
    </nav>
    <div>content</div>
  </div>
</div>

CSS : (sorry I'm not used to SCSS)

.test {
  width:400px;
  position:relative;
  > div, nav {
    border:3px solid #CCC;
  }
  > div:first-child {
    height:30px;
    z-index:10;
    background:teal;
    position:relative;
    z-index:1;
    span {
      float:right;
      display:table;
      height:100%;
      &:hover {
        cursor:pointer;
      }
    }
  }
  nav {
    width:100%;
    box-sizing:border-box;
    z-index:5;
    &.showmenu {
      margin-top:0;
    }
  }
}
.content > div{
  min-height:200px;
    position:absolute;
    left:-3px; top:100%;
    width:100%;
  border:3px solid #ccc;
}
.content{
  z-index:0;
  transform: translateY(-100%);
  -webkit-transform: translateY(-100%);
  -webkit-transition: all 1s ease-in-out;
    -moz-transition: all 1s ease-in-out;
    -o-transition: all 1s ease-in-out;
    transition: all 1s ease-in-out;
}
.content.showmenu{
  transform: translateY(0);
  -webkit-transform: translateY(0);
}

jQuery :

$( ".menulink" ).click(function() {
  $( ".content" ).toggleClass( "showmenu" );
});