_utility.scss

$defalutColor:#000;
$colors: ( headingColor: #6446ff, preragraphColor: #1b1b1b, linkColor: #1dc506); //decleared color
@function color($value:$defalutColor) {
    @if map-has-key($colors, $value) {
        @return map-get($colors, $value);
    }
    @return $defalutColor; //when not decleared color then the return default color
}

$default:0px; //set the deafult vlaue for needed instant refarance:$default ok
//padding utility
@mixin p($value) {
    padding: $value !important;
}

@mixin px($value:$default) {
    padding-left: $value !important;
    padding-right: $value !important;
}

@mixin py($value:$default) {
    padding-top: $value !important;
    padding-bottom: $value !important;
}

@mixin pl($value:$default) {
    padding-left: $value !important;
}

@mixin pr($value:$default) {
    padding-right: $value !important;
}

//margin utility
@mixin m($value:$default) {
    margin: $value !important;
}

@mixin mx($value:$default) {
    margin-left: $value !important;
    margin-right: $value !important;
}

@mixin my($value:$default) {
    margin-top: $value !important;
    margin-bottom: $value !important;
}

@mixin ml($value:$default) {
    margin-left: $value !important;
}

@mixin mr($value:$default) {
    margin-right: $value !important;
}

//uses
header {
    @include py(10px);
    @include px(30px);
    nav li {
        display: inline-block;
        a {
            font-size: 15px;
            //color: color(linkColor); //call the function for set color
            color: color(); // when blank call then the give function default color it's predefined
            @include p(30px);
            border: 1px solid red;
        }
    }
}