Duotone twilight and dim gray gradient palette editor

/* https://grabient.com/_gHkgFNgINgCBgEZgBKgOlgHUgNGgIegLigKN?style=linearGradient&steps=7&angle=135 */

background: linear-gradient(135deg, #5c507b 0.000%, #71728b 16.667%, #8f8d97 33.333%, #9c9b97 50.000%, #8c998a 66.667%, #6e877b 83.333%, #5b6873 100.000%);

<svg xmlns="http://www.w3.org/2000/svg" width="800" height="400" viewBox="0 0 800 400" preserveAspectRatio="none">
            <!-- https://grabient.com/_gHkgFNgINgCBgEZgBKgOlgHUgNGgIegLigKN?style=linearGradient&steps=7&angle=135 -->
            <defs>
              <linearGradient id="gradient" x1="0.146" y1="0.146" x2="0.854" y2="0.854">
        <stop offset="0.000" stop-color="#5c507b" /><stop offset="0.167" stop-color="#71728b" /><stop offset="0.333" stop-color="#8f8d97" /><stop offset="0.500" stop-color="#9c9b97" /><stop offset="0.667" stop-color="#8c998a" /><stop offset="0.833" stop-color="#6e877b" /><stop offset="1.000" stop-color="#5b6873" />
              </linearGradient>
            </defs>
            <rect x="0" y="0" width="800" height="400" fill="url(#gradient)" />
          </svg>

["#5c507b", "#71728b", "#8f8d97", "#9c9b97", "#8c998a", "#6e877b", "#5b6873"]

// https://grabient.com/_gHkgFNgINgCBgEZgBKgOlgHUgNGgIegLigKN?style=linearGradient&steps=7&angle=135
// cosine gradient palette — https://iquilezles.org/articles/palettes/
const float STEPS = 7.0;
const float ANGLE = 135.0;

vec3 palette(float t) {
    vec3 a = vec3(0.484, 0.333, 0.525);
    vec3 b = vec3(0.129, 0.281, 0.074);
    vec3 c = vec3(0.933, 0.468, 0.838);
    vec3 d = vec3(0.542, 0.738, 0.653);
    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);
}

[
  [0.484, 0.333, 0.525],
  [0.129, 0.281, 0.074],
  [0.933, 0.468, 0.838],
  [0.542, 0.738, 0.653]
]