Edit in JSFiddle

body {
    font-size:62.5%;
}

@mixin placeholder($c) {
    &:-moz-placeholder {
        color:$c;
    }
    &::-webkit-input-placeholder {
        color:$c;    
    }
}

@mixin bdradius($s) {
    -moz-obrder-radius:$s;
    -webkit-border-radius:$s;
    -o-border-radius:$s;
    -ms-border-radius:$s;
    border-radius:$s;
}

.test {
    padding:0.4rem 0.5rem;
    outline:none;
    background-color:#C0D8F7;
    border:none;
    color:#5C9CEE;
    font-size:2rem;
    @include bdradius(5px);
    @include placeholder(#B8CCE6);
    
}