/* https://grabient.com/_gNVgK5gQgf89gBkgCEf2-f8Nf65f_dgAvf9Af9vfzcjd?style=linearSwatches&steps=3&angle=90 */

background: linear-gradient(90deg, #c5aeff 0.000%, #c5aeff 33.333%, #c2c4ff calc(33.333% + 1px), #c2c4ff 66.667%, #ffcaf5 calc(66.667% + 1px) 100.000%);

<svg xmlns="http://www.w3.org/2000/svg" width="800" height="400" viewBox="0 0 800 400" preserveAspectRatio="none">
            <!-- https://grabient.com/_gNVgK5gQgf89gBkgCEf2-f8Nf65f_dgAvf9Af9vfzcjd?style=linearSwatches&steps=3&angle=90 -->
            <defs>
              <clipPath id="bounds">
                <rect x="0" y="0" width="800" height="400" />
              </clipPath>
            </defs>
            <g clip-path="url(#bounds)"><path d="M 0.000,647.214 L 0.000,-247.214 L 266.667,-247.214 L 266.667,647.214 Z" fill="#c5aeff" fill-opacity="1.000" /><path d="M 266.667,647.214 L 266.667,-247.214 L 533.333,-247.214 L 533.333,647.214 Z" fill="#c2c4ff" fill-opacity="1.000" /><path d="M 533.333,647.214 L 533.333,-247.214 L 800.000,-247.214 L 800.000,647.214 Z" fill="#ffcaf5" fill-opacity="1.000" /></g>
          </svg>

["#c5aeff", "#c2c4ff", "#ffcaf5"]

// https://grabient.com/_gNVgK5gQgf89gBkgCEf2-f8Nf65f_dgAvf9Af9vfzcjd?style=linearSwatches&steps=3&angle=90
// cosine gradient palette — https://iquilezles.org/articles/palettes/
const float STEPS = 3.0;
const float ANGLE = 90.0;

vec3 palette(float t) {
    vec3 a = vec3(0.850, 0.694, 1.053);
    vec3 b = vec3(-0.193, 0.099, 0.131);
    vec3 c = vec3(-0.719, -0.302, -0.407);
    vec3 d = vec3(0.186, 0.268, 0.029);
    return a + b * cos(6.283185 * (c * t + d));
}

// N hard swatches sampled from the palette
vec3 stops(float t) {
    float i = min(floor(clamp(t, 0.0, 1.0) * STEPS), STEPS - 1.0);
    return palette(i / (STEPS - 1.0));
}

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);
}

[
  [0.850, 0.694, 1.053],
  [-0.193, 0.099, 0.131],
  [-0.719, -0.302, -0.407],
  [0.186, 0.268, 0.029]
]

Gradient palette editor — #c5aeff to #ffcaf5