Gradient palette editor — #31120d to #dffdff

/* https://grabient.com/_edlgHjgKohx0gIfgK2gBngKfgGQgOdgGDgGu */

background: linear-gradient(90deg, #31120d 0.000%, #820000 16.667%, #bf110a 33.333%, #e76334 50.000%, #fac173 66.667%, #f7febc 83.333%, #dffdff 100.000%);

<svg xmlns="http://www.w3.org/2000/svg" width="800" height="400" viewBox="0 0 800 400" preserveAspectRatio="none">
            <!-- https://grabient.com/_edlgHjgKohx0gIfgK2gBngKfgGQgOdgGDgGu -->
            <defs>
              <linearGradient id="gradient" x1="0.000" y1="0.500" x2="1.000" y2="0.500">
        <stop offset="0.000" stop-color="#31120d" /><stop offset="0.167" stop-color="#820000" /><stop offset="0.333" stop-color="#bf110a" /><stop offset="0.500" stop-color="#e76334" /><stop offset="0.667" stop-color="#fac173" /><stop offset="0.833" stop-color="#f7febc" /><stop offset="1.000" stop-color="#dffdff" />
              </linearGradient>
            </defs>
            <rect x="0" y="0" width="800" height="400" fill="url(#gradient)" />
          </svg>

["#31120d", "#820000", "#bf110a", "#e76334", "#fac173", "#f7febc", "#dffdff"]

// https://grabient.com/_edlgHjgKohx0gIfgK2gBngKfgGQgOdgGDgGu
// 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(-6.299, 0.483, 0.680);
    vec3 b = vec3(7.284, 0.543, 0.694);
    vec3 c = vec3(0.103, 0.671, 0.400);
    vec3 d = vec3(0.925, 0.387, 0.430);
    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);
}

[
  [-6.299, 0.483, 0.680],
  [7.284, 0.543, 0.694],
  [0.103, 0.671, 0.400],
  [0.925, 0.387, 0.430]
]