Edit in JSFiddle

<div class="main">
    <svg viewBox="0 0 20 20" width="100%">
        <circle cx="10" cy="10" r="9"/>
    </svg>
</div>
.main {
   display: inline-block; 
   width: 30%; 
   border: solid 1px gray;
}
svg {
    stroke: red;
    fill: black;
    stroke-width: 0.5;
}