Fixed Header Div With Scrollable Div Below

I'm trying to place two divs one above the other. The top one has a fixed size. The bottom one needs to fill the rest of the page height, without making the page higher if it's con

Solution 1:

Try this:

#stuff {
   overflow-x:auto;
   background-color: lightgreen;
   top:30px;  /* as the height of the other div is 30px */
   left:0;
   right:0;
   bottom:0;
   position:absolute;
}

Working Fiddle

Solution 2:

In case if anyone wants to solve this keeping things in normal flow, nowadays this can be done using the flexbox layout model as shown below:

* {
  margin: 0;
  padding: 0;
}
html,
body {
  height: 100%;
}
#content {
  display: flex;
  flex-direction: column;
  width: 300px;
  height: 100%;
  margin: 0 auto;
  background-color: #C9E6FF;
}
#top-padding {
  height: 30px;
  flex: none;
  background: blue;
}
#stuff {
  flex: auto;
  overflow-y: auto;
  background-color: lightgreen;
}
/*for demo purpose */

#stuff p {
  height: 1000px;
}

<div id="content">
  <div id="top-padding"></div>
  <div id="stuff">
    <p>some content</p>
  </div>
</div>

Solution 3:

And in case if anyone wants to solve this keeping things in normal flow and without using flex, then solution is as follows:

html,
    body {
        height: 100%;
    }

    body {
        margin: 0;
    }

    #content {
        height: 100vh;
        position: relative;
        background-color: #C9E6FF;
        margin: 0 auto;
        width: 300px;
    }

    #top-padding {
        background: blue;
        height: 30px;
    }

    #stuff {
        overflow-x:auto;
        background-color: lightgreen;
        height: calc(100vh - 30px);
    }

<div id="content">
    <div id="top-padding"></div>
        <div id="stuff">
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       </div>
   </div>