JSFiddle - React, Tailwind, and code Playground

HTML

Tabs:
<pre>
test
<span>	</span>test
<span>	</span><span>	</span>123
<span>	</span><span>	</span>test3
<span>	</span><span>	</span><span>	</span>test
<span>	</span><span>	</span>test4
<span>	</span><span>	</span>test5
</pre>

Spaces:
<pre>
test
  test
    123
      test3
        test
      test4
    test5
</pre>

Tabs &amp; Spaces gemischt:
<pre>
test
  test
  <span>	</span>123
<span>	</span><span>	</span>test3
      test
  <span>	</span>test4
    test5
</pre>

CSS

pre span {
  display: inline-block;
  border: 0 none;
  margin: 0;
  padding: 0;
  width: 1.618033988749895em;
  overflow: hidden;
}