Sidebar which can scroll but with the main content fixed

Question

I am attempting to create a sidebar which can scroll, but the main content on the right is fixed (no scroll).

But when I try to work around it does not work, so here is an example

HTML

<div id="container">
    <div id="outer-wrapper" class="is-open">
        <div id="inner-wrapper">
        </div>
        <div id="sidebar">
        </div>
    </div>
</div>

CSS

#sidebar {
    height: 100%;
    position: absolute;
    top: 0;
    left: -80%;
    width: 80%;
}

.is-open {
    //expose the sidebar by translating the wrapper
    -webkit-transform: translateX(80%);
    transform: translateX(80%);
}

#container {
    //disables horizontal scroll
    overflow: hidden;
}

Here is the fiddle that might help with testing https://jsfiddle.net/minheq/tn2no1o6/3/

Please, any advice on this?

Answer 1

Something like this?

body {
  width: 100%;
  height: 100%;
  overflow: hidden;
}

.container, .wrapper {
  display: block;
  width: 100%;
  height: 100%;
  overflow: hidden;
}

.content {
  width: 100%;
  height: 100%;
  position: absolute;
  top: 0;
  left: 0;
  z-index: 0;
  background: #ddd;
  padding: 10px;
  padding-left: 230px;
}
.sidebar {
  width: 200px;
  height: 100%;
  position: absolute;
  left: 0;
  top: 0;
  padding: 10px;
  background: #849;
  overflow: auto;
}
.sidebar-content {
  width: 100%;
  height: 600px;
  background: #994;
  z-index: 1;
}

<div class="container">
  <div class="wrapper">
    <div class="content">Lorem ipsum dolor</div>
    <div class="sidebar">
      <div class="sidebar-content">Amet dolor ipsum</div>
    </div>
  </div>
</div>