Color for sombr, Potential

<path d="M40 20C40 31.0457 31.0457 40 20 40C8.9543 40 0 31.0457 0 20C0 8.9543 8.9543 0 20 0C31.0457 0 40 8.9543 40 20ZM38 20C38 29.9411 29.9411 38 20 38C10.0589 38 2 29.9411 2 20C2 10.0589 10.0589 2 20 2C29.9411 2 38 10.0589 38 20Z" clip-rule="evenodd" fill-rule="evenodd"> Color for sombr, Potential