https://i.stack.imgur.com/bitod.png
In comparing this particular fiddle with another version of the same fiddle, the only variance is that in the second one, there is
</label><label for="address_zip" class="zip">
without a line break following the closing </label>
tag.
https://i.stack.imgur.com/mr9b4.png
<label for="address_state" class="state">
<span>State</span><input name="address_state" type="text" placeholder="CA" required="" class="field is-empty">
</label><label for="address_zip" class="zip">
<span>ZIP</span><input name="address_zip" type="text" placeholder="94107" required="" class="field is-empty">
</label>
Dealing with line breaks can be quite tricky, and I've faced similar issues in the past.
Initially, I decided to accept the lack of a new line after the closing label tag in the HTML, even though it appeared messy.
However, I then discovered that another webpage (almost identical except for different CSS) that I had coded did not have this line break problem.
https://i.stack.imgur.com/7fCs1.png
Why might this be?