Created by: zalog
To avoid this when setting a bigger $line-height
with flexbox enabled:
line-height should be the same as on body, and .form-control
<fieldset class="form-group">
<div class="input-group">
<span class="input-group-addon" id="sizing-addon2">$</span>
<input type="text" class="form-control" placeholder="Username" aria-describedby="sizing-addon2">
</div>
</fieldset>