body {
font-family: tahoma, sans-serif;
font-size: 12px;
margin: 10px;
}
article {
display: flex;
}
aside {
flex: 0 1 10px;
margin-right: 10px;
min-width: 10px;
position: relative;
}
svg {
bottom: 0;
left: 0;
position: absolute;
right: 0;
top: 0;
}
.backgroundStop1 {
stop-color: #5bb79e;
}
.backgroundStop2 {
stop-color: #ddcb3f;
}
.backgroundStop3 {
stop-color: #cf6b19;
}
<article>
<aside>
<svg version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" height="100%" width="100%">
<defs>
<linearGradient id="IndicatorColourPattern" x1="0" x2="0" y1="0" y2="1">
<stop class="backgroundStop1" offset="0%"></stop>
<stop class="backgroundStop2" offset="50%"></stop>
<stop class="backgroundStop3" offset="100%"></stop>
</linearGradient>
</defs>
<rect x="0" y="0" rx="5" ry="5" width="100%" height="100%" fill="url(#IndicatorColourPattern)"></rect>
</svg>
</aside>
<section>
<p>Donec et eros nibh. Nullam porta, elit ut sagittis pulvinar, lacus augue lobortis mauris, sed sollicitudin elit orci non massa. Proin condimentum in nibh sed vestibulum. Donec accumsan fringilla est, porttitor vestibulum dolor ornare id. Sed elementum
urna sollicitudin commodo ultricies. Curabitur tristique orci et ligula interdum, eu condimentum metus eleifend. Nam libero augue, pharetra at maximus in, pellentesque imperdiet orci.</p>
<p>Fusce commodo ullamcorper ullamcorper. Etiam eget pellentesque quam, id sodales erat. Vestibulum risus magna, efficitur sed nisl et, rutrum consectetur odio. Sed at lorem non ligula consequat tempus vel nec risus.</p>
</section>
</article>