Gradient palette editor — #081000 to #458696

/* https://grabient.com/_gCcgFegB4gCbgFPgRmgIIgGmgBmgJWgGfgLM */

background: linear-gradient(90deg, #081000 0.000%, #180400 16.667%, #2d091f 33.333%, #411d3d 50.000%, #4d3d5b 66.667%, #4f6279 83.333%, #458696 100.000%);

<svg xmlns="http://www.w3.org/2000/svg" width="800" height="400" viewBox="0 0 800 400" preserveAspectRatio="none">
            <!-- https://grabient.com/_gCcgFegB4gCbgFPgRmgIIgGmgBmgJWgGfgLM -->
            <defs>
              <linearGradient id="gradient" x1="0.000" y1="0.500" x2="1.000" y2="0.500">
        <stop offset="0.000" stop-color="#081000" /><stop offset="0.167" stop-color="#180400" /><stop offset="0.333" stop-color="#2d091f" /><stop offset="0.500" stop-color="#411d3d" /><stop offset="0.667" stop-color="#4d3d5b" /><stop offset="0.833" stop-color="#4f6279" /><stop offset="1.000" stop-color="#458696" />
              </linearGradient>
            </defs>
            <rect x="0" y="0" width="800" height="400" fill="url(#gradient)" />
          </svg>

["#081000", "#180400", "#2d091f", "#411d3d", "#4d3d5b", "#4f6279", "#458696"]

// https://grabient.com/_gCcgFegB4gCbgFPgRmgIIgGmgBmgJWgGfgLM
// cosine gradient palette — https://iquilezles.org/articles/palettes/
const float STEPS = 7.0;
const float ANGLE = 90.0;

vec3 palette(float t) {
    vec3 a = vec3(0.156, 0.350, 0.120);
    vec3 b = vec3(0.155, 0.335, 1.126);
    vec3 c = vec3(0.520, 0.422, 0.102);
    vec3 d = vec3(0.598, 0.415, 0.716);
    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);
}

[
  [0.156, 0.350, 0.120],
  [0.155, 0.335, 1.126],
  [0.520, 0.422, 0.102],
  [0.598, 0.415, 0.716]
]