• HTML
• CSS

HTML

<div>
    <span></span>
</div>

CSS

div{
    height:20rem;
    width:20rem;
    background: radial-gradient(
        circle at 33% 100%,
        #fed373 4%,
        #f15245 30%,
        #d92e7f 62%,
        #9b36b7 85%,
        #515ecf
    );
    border-radius:30%;
    position:relative;
}

div:before{
    content:'';
    border:1rem solid #fff;
    border-radius:30%;
    width:12.5rem;
    height:12.5rem;
    left:0;
    right:0;
    position:absolute;
    margin:auto;
    top:0;
    bottom:0;
}

div:after{
    content:'';
    border:1rem solid #fff;
    border-radius:100%;
    width:5rem;
    height:5rem;
    left:0;
    right:0;
    position:absolute;
    margin:auto;
    top:0;
    bottom:0;
}

span{
    content:'';
    border:1rem solid #fff;
    border-radius:100%;
    width:0rem;
    height:0rem;
    right:5rem;
    position:absolute;
    margin:auto;
    top:5rem;
}

/* todos los créditos para midudev */