// transition
@mixin custom-transition($property,$time) {
    -webkit-transition: $property $time + s;
    -o-transition: $property $time + s;
    transition: $property $time + s;
}

// display flex
@mixin d-flex() {
    display: -webkit-box; 
    display: -moz-box;
    display: -ms-flexbox;
    display: -webkit-flex; 
    display: flex;
}

// circle 
@mixin circle($wh) {
    width: $wh + px;
    height: $wh + px;
    border-radius: 50%;
}
