/* https://grabient.com/_gH0gIMgKRgJQgJBgL6gL2gMtgIEgNBgIGgFg?style=linearGradient&steps=7&angle=225 */

background: linear-gradient(225deg, #cb0033 0.000%, #ff3200 16.667%, #ffa900 33.333%, #a3ff12 50.000%, #30ff67 66.667%, #00b7ce 83.333%, #013eff 100.000%);

<svg xmlns="http://www.w3.org/2000/svg" width="800" height="400" viewBox="0 0 800 400" preserveAspectRatio="none">
            <!-- https://grabient.com/_gH0gIMgKRgJQgJBgL6gL2gMtgIEgNBgIGgFg?style=linearGradient&steps=7&angle=225 -->
            <defs>
              <linearGradient id="gradient" x1="0.854" y1="0.146" x2="0.146" y2="0.854">
        <stop offset="0.000" stop-color="#cb0033" /><stop offset="0.167" stop-color="#ff3200" /><stop offset="0.333" stop-color="#ffa900" /><stop offset="0.500" stop-color="#a3ff12" /><stop offset="0.667" stop-color="#30ff67" /><stop offset="0.833" stop-color="#00b7ce" /><stop offset="1.000" stop-color="#013eff" />
              </linearGradient>
            </defs>
            <rect x="0" y="0" width="800" height="400" fill="url(#gradient)" />
          </svg>

["#cb0033", "#ff3200", "#ffa900", "#a3ff12", "#30ff67", "#00b7ce", "#013eff"]

// https://grabient.com/_gH0gIMgKRgJQgJBgL6gL2gMtgIEgNBgIGgFg?style=linearGradient&steps=7&angle=225
// cosine gradient palette — https://iquilezles.org/articles/palettes/
const float STEPS = 7.0;
const float ANGLE = 225.0;

vec3 palette(float t) {
    vec3 a = vec3(0.500, 0.524, 0.657);
    vec3 b = vec3(0.592, 0.577, 0.762);
    vec3 c = vec3(0.758, 0.813, 0.516);
    vec3 d = vec3(0.833, 0.518, 0.352);
    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);
}

[
  [0.500, 0.524, 0.657],
  [0.592, 0.577, 0.762],
  [0.758, 0.813, 0.516],
  [0.833, 0.518, 0.352]
]

Gradient palette editor — #cb0033 to #013eff