/* https://grabient.com/_gMRgAAgGPgMegAAgZVgBfgBjgBkgK9gAAgLo?style=linearGradient&steps=5&angle=315 */

background: linear-gradient(315deg, #8b0056 0.000%, #a80097 25.000%, #c600d7 50.000%, #e500ff 75.000%, #ff00ff 100.000%);

<svg xmlns="http://www.w3.org/2000/svg" width="800" height="400" viewBox="0 0 800 400" preserveAspectRatio="none">
            <!-- https://grabient.com/_gMRgAAgGPgMegAAgZVgBfgBjgBkgK9gAAgLo?style=linearGradient&steps=5&angle=315 -->
            <defs>
              <linearGradient id="gradient" x1="0.854" y1="0.854" x2="0.146" y2="0.146">
        <stop offset="0.000" stop-color="#8b0056" /><stop offset="0.250" stop-color="#a80097" /><stop offset="0.500" stop-color="#c600d7" /><stop offset="0.750" stop-color="#e500ff" /><stop offset="1.000" stop-color="#ff00ff" />
              </linearGradient>
            </defs>
            <rect x="0" y="0" width="800" height="400" fill="url(#gradient)" />
          </svg>

["#8b0056", "#a80097", "#c600d7", "#e500ff", "#ff00ff"]

// https://grabient.com/_gMRgAAgGPgMegAAgZVgBfgBjgBkgK9gAAgLo?style=linearGradient&steps=5&angle=315
// cosine gradient palette — https://iquilezles.org/articles/palettes/
const float STEPS = 5.0;
const float ANGLE = 315.0;

vec3 palette(float t) {
    vec3 a = vec3(0.785, 0.000, 0.399);
    vec3 b = vec3(0.798, 0.000, 1.621);
    vec3 c = vec3(0.095, 0.099, 0.100);
    vec3 d = vec3(0.701, 0.000, 0.744);
    return a + b * cos(6.283185 * (c * t + d));
}

// N stops sampled from the palette, blended like the CSS gradient
vec3 stops(float t) {
    float n = STEPS - 1.0;
    float x = clamp(t, 0.0, 1.0) * n;
    return mix(palette(floor(x) / n), palette(min(floor(x) + 1.0, n) / n), fract(x));
}

void mainImage(out vec4 fragColor, in vec2 fragCoord) {
    vec2 p = fragCoord - 0.5 * iResolution.xy;
    // CSS angle: 0 = up, clockwise; span = CSS gradient-line length
    vec2 dir = vec2(sin(radians(ANGLE)), cos(radians(ANGLE)));
    float len = abs(iResolution.x * dir.x) + abs(iResolution.y * dir.y);
    float t = dot(p, dir) / len + 0.5;
    fragColor = vec4(stops(t), 1.0);
}

[
  [0.785, 0.000, 0.399],
  [0.798, 0.000, 1.621],
  [0.095, 0.099, 0.100],
  [0.701, 0.000, 0.744]
]

Gradient palette editor — #8b0056 to #ff00ff