How to change checkbox's border style in CSS?

Question

I suggest using "outline" instead of "border". For example: outline: 1px solid #1e5180.

You should use

-moz-appearance:none;
-webkit-appearance:none;
-o-appearance:none;

Then you get rid of the default checkbox image/style and can style it. Anyway a border will still be there in Firefox

If something happens in any browser I'd be surprised. This is one of those outstanding form elements that browsers tend not to let you style that much, and that people usually try to replace with javascript so they can style/code something to look and act like a checkbox.

You can use box shadows to fake a border:

-webkit-box-shadow: 0px 0px 0px 1px rgba(255,0,0,1);
-moz-box-shadow: 0px 0px 0px 1px rgba(255,0,0,1);
box-shadow: 0px 0px 0px 1px rgba(255,0,0,1);

Here is a pure CSS (no images) cross-browser solution based on Martin's Custom Checkboxes and Radio Buttons with CSS3 LINK: http://martinivanov.net/2012/12/21/imageless-custom-checkboxes-and-radio-buttons-with-css3-revisited/

Here is a jsFiddle: http://jsfiddle.net/DJRavine/od26wL6n/

I have tested this on the following browsers:

• FireFox (41.0.2) (42)
• Google Chrome (46.0.2490.80 m)
• Opera (33.0.1990.43)
• Internet Explorer (11.0.10240.16431 [Update Versions: 11.0.22])
• Microsoft Edge (20.10240.16384.0)
• Safari Mobile iPhone iOS9 (601.1.46)

label,
input[type="radio"] + span,
input[type="radio"] + span::before,
label,
input[type="checkbox"] + span,
input[type="checkbox"] + span::before
{
    display: inline-block;
    vertical-align: middle;
}
 
label *,
label *
{
    cursor: pointer;
}
 
input[type="radio"],
input[type="checkbox"]
{
    opacity: 0;
    position: absolute;
}
 
input[type="radio"] + span,
input[type="checkbox"] + span
{
    font: normal 11px/14px Arial, Sans-serif;
    color: #333;
}
 
label:hover span::before,
label:hover span::before
{
    -moz-box-shadow: 0 0 2px #ccc;
    -webkit-box-shadow: 0 0 2px #ccc;
    box-shadow: 0 0 2px #ccc;
}
 
label:hover span,
label:hover span
{
    color: #000;
}
 
input[type="radio"] + span::before,
input[type="checkbox"] + span::before
{
    content: "";
    width: 12px;
    height: 12px;
    margin: 0 4px 0 0;
    border: solid 1px #a8a8a8;
    line-height: 14px;
    text-align: center;
     
    -moz-border-radius: 100%;
    -webkit-border-radius: 100%;
    border-radius: 100%;
     
    background: #f6f6f6;
    background: -moz-radial-gradient(#f6f6f6, #dfdfdf);
    background: -webkit-radial-gradient(#f6f6f6, #dfdfdf);
    background: -ms-radial-gradient(#f6f6f6, #dfdfdf);
    background: -o-radial-gradient(#f6f6f6, #dfdfdf);
    background: radial-gradient(#f6f6f6, #dfdfdf);
}
 
input[type="radio"]:checked + span::before,
input[type="checkbox"]:checked + span::before
{
    color: #666;
}
 
input[type="radio"]:disabled + span,
input[type="checkbox"]:disabled + span
{
    cursor: default;
     
    -moz-opacity: .4;
    -webkit-opacity: .4;
    opacity: .4;
}
 
input[type="checkbox"] + span::before
{
    -moz-border-radius: 2px;
    -webkit-border-radius: 2px;
    border-radius: 2px;
}
 
input[type="radio"]:checked + span::before
{
    content: "\2022";
    font-size: 30px;
    margin-top: -1px;
}
 
input[type="checkbox"]:checked + span::before
{
    content: "\2714";
    font-size: 12px;
}



input[class="blue"] + span::before
{
    border: solid 1px blue;
    background: #B2DBFF;
    background: -moz-radial-gradient(#B2DBFF, #dfdfdf);
    background: -webkit-radial-gradient(#B2DBFF, #dfdfdf);
    background: -ms-radial-gradient(#B2DBFF, #dfdfdf);
    background: -o-radial-gradient(#B2DBFF, #dfdfdf);
    background: radial-gradient(#B2DBFF, #dfdfdf);
}
input[class="blue"]:checked + span::before
{
    color: darkblue;
}



input[class="red"] + span::before
{
    border: solid 1px red;
    background: #FF9593;
    background: -moz-radial-gradient(#FF9593, #dfdfdf);
    background: -webkit-radial-gradient(#FF9593, #dfdfdf);
    background: -ms-radial-gradient(#FF9593, #dfdfdf);
    background: -o-radial-gradient(#FF9593, #dfdfdf);
    background: radial-gradient(#FF9593, #dfdfdf);
}
input[class="red"]:checked + span::before
{
    color: darkred;
}

 <label><input type="radio" checked="checked" name="radios-01" /><span>checked radio button</span></label>
 <label><input type="radio" name="radios-01" /><span>unchecked radio button</span></label>
 <label><input type="radio" name="radios-01" disabled="disabled" /><span>disabled radio button</span></label>

<br/>

 <label><input type="radio" checked="checked" name="radios-02"  class="blue" /><span>checked radio button</span></label>
 <label><input type="radio" name="radios-02" class="blue" /><span>unchecked radio button</span></label>
 <label><input type="radio" name="radios-02" disabled="disabled" class="blue" /><span>disabled radio button</span></label>

<br/>

 <label><input type="radio" checked="checked" name="radios-03"  class="red" /><span>checked radio button</span></label>
 <label><input type="radio" name="radios-03" class="red" /><span>unchecked radio button</span></label>
 <label><input type="radio" name="radios-03" disabled="disabled" class="red" /><span>disabled radio button</span></label>

<br/>
 
<label><input type="checkbox" checked="checked" name="checkbox-01" /><span>selected checkbox</span></label>
<label><input type="checkbox" name="checkbox-02" /><span>unselected checkbox</span></label>
<label><input type="checkbox" name="checkbox-03" disabled="disabled" /><span>disabled checkbox</span></label>

<br/>
 
<label><input type="checkbox" checked="checked" name="checkbox-01" class="blue" /><span>selected checkbox</span></label>
<label><input type="checkbox" name="checkbox-02" class="blue" /><span>unselected checkbox</span></label>
<label><input type="checkbox" name="checkbox-03" disabled="disabled" class="blue" /><span>disabled checkbox</span></label>

<br/>
 
<label><input type="checkbox" checked="checked" name="checkbox-01" class="red" /><span>selected checkbox</span></label>
<label><input type="checkbox" name="checkbox-02" class="red" /><span>unselected checkbox</span></label>
<label><input type="checkbox" name="checkbox-03" disabled="disabled" class="red" /><span>disabled checkbox</span></label>