filebutton.scss

a.upload {
    display: inline-block;
    position: relative;

    input[type=file] {
        position: absolute;
        top: 0;
        right: 0;
        bottom: 0;
        left: 0;
        opacity: 0;
        cursor: pointer;
        margin-bottom: 0;
        height: 100%;

        &::-ms-value {
            display: none;
        }

        &::-ms-browse {
            width: 100%;
        }
    }
}