カスタムUIのチェックボックス・ラジオボタン ref: http://qiita.com/butchi_y/items/936eff265e45c6a2165d

file0.css

body {
    background-color: #fff;
}

input[type="checkbox"],
input[type="radio"] {
    position: absolute;
    width:    0;
    height:   0;
    top:      0;
    left:     0;
    opacity:  0;
}

input[type="checkbox"] + *,
input[type="radio"] + * {
    position: relative;
    display: inline-block;

    box-sizing: border-box;
}

[type="checkbox"] + * {
    margin-left:  17px;
    padding-left: -3px;

    line-height: 12px;
}

[type="checkbox"] + *::before,
[type="checkbox"] + *::after {
    content:    "";
    display:    block;
    position:   absolute;
    box-sizing: border-box;
    width:      12px;
    height:     12px;
    left:       -14px;
    top:        0px;
}

[type="checkbox"] + *::before {
    background-color: #fff;
    border: 1px solid #000;
}

[type="checkbox"]:checked + *::after {
    position: absolute;
    width:  6px;
    height: 6px;
    margin-left: 3px;
    margin-top:  3px;
    background: #000;
}

[type="radio"] + * {
    margin-left:  17px;
    padding-left: 0;

    line-height: 16px;
}

[type="radio"] + *::before,
[type="radio"] + *::after {
    box-sizing: border-box;
    content:    "";
    display:    block;
    position:   absolute;
    width:      16px;
    height:     16px;
    left:       -16px;
    top:        0px;
}

[type="radio"] + *::before {
    background-color: #fff;
    border: 1px solid #000;

    border-radius: 16px;
}

[type="radio"]:checked + *::after {
    position: absolute;
    width:       8px;
    height:      8px;
    margin-left: 4px;
    margin-top:  4px;
    background:  #000;

    border-radius: 8px;
}

[type="checkbox"]:disabled + *::before,
[type="checkbox"]:disabled + *::after,
[type="radio"]:disabled + *::before,
[type="checkbox"]:disabled + *::after {
    opacity: 0.25;
}

[type="checkbox"]:focus + *::before,
[type="radio"]:focus + *::before {
    box-shadow: 1px 1px 0px #000;
}