Gradient palette editor — #131d28 to #312b34

/* https://grabient.com/_gB3gDDgCwgBTgBXgAegLkgR2gUqgFYgItgJ1?style=linearGradient&steps=8&angle=225 */

background: linear-gradient(225deg, #131d28 0.000%, #0a2e30 14.286%, #0a4235 28.571%, #13472f 42.857%, #213727 57.143%, #2d2226 71.429%, #331c2d 85.714%, #312b34 100.000%);

<svg xmlns="http://www.w3.org/2000/svg" width="800" height="400" viewBox="0 0 800 400" preserveAspectRatio="none">
            <!-- https://grabient.com/_gB3gDDgCwgBTgBXgAegLkgR2gUqgFYgItgJ1?style=linearGradient&steps=8&angle=225 -->
            <defs>
              <linearGradient id="gradient" x1="0.854" y1="0.146" x2="0.146" y2="0.854">
        <stop offset="0.000" stop-color="#131d28" /><stop offset="0.143" stop-color="#0a2e30" /><stop offset="0.286" stop-color="#0a4235" /><stop offset="0.429" stop-color="#13472f" /><stop offset="0.571" stop-color="#213727" /><stop offset="0.714" stop-color="#2d2226" /><stop offset="0.857" stop-color="#331c2d" /><stop offset="1.000" stop-color="#312b34" />
              </linearGradient>
            </defs>
            <rect x="0" y="0" width="800" height="400" fill="url(#gradient)" />
          </svg>

["#131d28", "#0a2e30", "#0a4235", "#13472f", "#213727", "#2d2226", "#331c2d", "#312b34"]

// https://grabient.com/_gB3gDDgCwgBTgBXgAegLkgR2gUqgFYgItgJ1?style=linearGradient&steps=8&angle=225
// cosine gradient palette — https://iquilezles.org/articles/palettes/
const float STEPS = 8.0;
const float ANGLE = 225.0;

vec3 palette(float t) {
    vec3 a = vec3(0.119, 0.195, 0.176);
    vec3 b = vec3(0.083, 0.087, 0.030);
    vec3 c = vec3(0.740, 1.142, 1.322);
    vec3 d = vec3(0.344, 0.557, 0.629);
    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);
}

[
  [0.119, 0.195, 0.176],
  [0.083, 0.087, 0.030],
  [0.740, 1.142, 1.322],
  [0.344, 0.557, 0.629]
]