Span adding unexpected height to sibling - css

Question

I am having trouble adding a validation indicator to my input fields in my creditcards form.
For some reason, having the span adds height to the span.input-group-addon, resulting in empty space below the input
<template name="checkoutForm">
<div class="modal-content">
<div class="modal-header">
<button type="button" class="close" data-dismiss="modal" aria-label="Close"><span aria-hidden="true">×</span></button>
<h4 class="modal-title">Title</h4>
</div>
<div class="modal-body">
<form class="bs-example bs-example-form">
<div class="no-margin">
<div class="col-xs-12">
<div class="input-group">
<span class="input-group-addon input-group-sm"><i class="fa fa-credit-card"></i></span>
<input type="text" class="form-control" id="checkoutCardNumber" placeholder="Card Number">
<span class="validity"></span>
</div>
</div>
And LESS
#import '../../../../stylesheets/variables.import.less';
#import '../../../../stylesheets/mixins.import.less';
.checkout-form {
max-width: 350px;
margin: auto;
.no-margin {
.form-group {
width: 80%;
margin: 0px;
}
}
.validity {
overflow: auto;
position: relative;
top: -27px;
left: 215px;
z-index: 1000;
.valid {
color: #brand-primary;
}
.invalid {
color: red;
}
}
}
How can I correct this?

Answer 1

One way of getting rid of the extra whitespace is removing the line feeds or spaces between elements
You can change
<input type="text" class="form-control" id="checkoutCardNumber" placeholder="Card Number">
<span class="validity"></span>
to
<input type="text" class="form-control" id="checkoutCardNumber" placeholder="Card Number"><span class="validity"></span>
Another way is to set the parent element class' font-size attribute to zero.
So try adding
font-size:0;
white-space:nowrap;
to input-group class. Or change the markup as follows
<div class="input-group" style="font-size:0;white-space:nowrap;">
But then you have to specify the font-size attribute in validity class in order to display the text within.
Another way is to add
float:left;
to validity class. You'll probably have to add that to input's class too.
EDIT
It appears that the problem has nothing to do with the issues above.
Simply remove <span class="validity"></span> outside of <div class="input-group"> as follows and see if that works
<div class="input-group">
<span class="input-group-addon input-group-sm"><i class="fa fa-credit-card"></i></span>
<input type="text" class="form-control" id="checkoutCardNumber" placeholder="Card Number">
</div>
<span class="validity"></span>
EDIT 2
Change validity class as follows
.validity {
overflow: auto;
position: absolute;
top: 5px;
left: 215px;
z-index: 1000;
}
and use the markup below (your original)
<div class="input-group">
<span class="input-group-addon input-group-sm"><i class="fa fa-credit-card"></i></span>
<input type="text" class="form-control" id="checkoutCardNumber" placeholder="Card Number">
<span class="validity"></span>
</div>