void mainImage(out vec4 fragColor, in vec2 fragCoord)
{
    vec2 uv = fragCoord.xy / iResolution.xy;

    vec2 p = uv * 2.0 - 1.0;

    p.x *= iResolution.x / iResolution.y;

    float t = iTime * 0.6;

    float glow =
        0.02 / abs(length(p) - 0.45);

    float waves =
        sin(p.x * 12.0 + t) *
        sin(p.y * 12.0 - t);

    float radial =
        sin(length(p) * 30.0 - t * 4.0);

    vec3 color = vec3(0.02, 0.04, 0.08);

    color += vec3(0.1, 0.7, 1.0) * glow;
    color += vec3(1.0, 0.2, 0.8) * waves * 0.3;
    color += vec3(0.4, 0.2, 1.0) * radial * 0.15;

    fragColor = vec4(color, 1.0);
}