CSS overflow and white-space not working - html

Question

Current Situation
Using the following code I show a couple of divs floated to the left.
* {
margin: 0;
padding: 0;
border: none;
box-sizing: border-box;
}
.container {
width: 100%;
height: 100%;
}
.header {
height: 80px;
position: fixed;
width: 100%;
background: green;
}
.inner-container {
position: absolute;
top: 80px;
left: 0px;
right: 0px;
bottom: 0px;
overflow: auto;
white-space: nowrap;
}
.column {
height: 500px;
width: 150px;
background: red;
float: left;
margin: 5px;
}
<div class="container">
<div class="header">
</div>
<div class="inner-container">
<div class="column">
</div>
<div class="column">
</div>
<div class="column">
</div>
</div>
</div>
Current result:
Problem
What I want is that the red boxes don't wrap within its container. I want both, a vertical and horizontal scroll bar if the space is not enough. For the vertical scrollbar it works. What am I missing?
JSFiddle: https://jsfiddle.net/brainchest/j6zh400v/

Answer 1

A fix I found was to change the .column from being a float: left to display: inline-block. This treats each column as a "word" (like a word in text) and thus the white-space: no-wrap; applies. Otherwise, the float: left changes the way the element gets positioned.
Edited Fiddle: https://jsfiddle.net/9bo4f5pv/

Answer 2

Use display: flex on the parent, then flex: 0 0 150px on the columns.
* {
margin: 0;
padding: 0;
border: none;
box-sizing: border-box;
}
.container {
width: 100%;
height: 100%;
}
.header {
height: 80px;
position: fixed;
width: 100%;
background: green;
}
.inner-container {
position: absolute;
top: 80px;
left: 0px;
right: 0px;
bottom: 0px;
overflow: auto;
display: flex;
}
.column {
height: 500px;
flex: 0 0 150px;
background: red;
margin: 5px;
}
<div class="container">
<div class="header">
</div>
<div class="inner-container">
<div class="column">
</div>
<div class="column">
</div>
<div class="column">
</div>
</div>
</div>