/* https://grabient.com/_e12gkNhUNhZpgh4hR3gBpgBhgBngOVgISgHG?style=linearGradient&steps=5&angle=90 */

background: linear-gradient(90deg, #3a305e 0.000%, #a14631 25.000%, #e26827 50.000%, #fc9540 75.000%, #efcd7b 100.000%);

<svg xmlns="http://www.w3.org/2000/svg" width="800" height="400" viewBox="0 0 800 400" preserveAspectRatio="none">
            <!-- https://grabient.com/_e12gkNhUNhZpgh4hR3gBpgBhgBngOVgISgHG?style=linearGradient&steps=5&angle=90 -->
            <defs>
              <linearGradient id="gradient" x1="0.000" y1="0.500" x2="1.000" y2="0.500">
        <stop offset="0.000" stop-color="#3a305e" /><stop offset="0.250" stop-color="#a14631" /><stop offset="0.500" stop-color="#e26827" /><stop offset="0.750" stop-color="#fc9540" /><stop offset="1.000" stop-color="#efcd7b" />
              </linearGradient>
            </defs>
            <rect x="0" y="0" width="800" height="400" fill="url(#gradient)" />
          </svg>

["#3a305e", "#a14631", "#e26827", "#fc9540", "#efcd7b"]

// https://grabient.com/_e12gkNhUNhZpgh4hR3gBpgBhgBngOVgISgHG?style=linearGradient&steps=5&angle=90
// cosine gradient palette — https://iquilezles.org/articles/palettes/
const float STEPS = 5.0;
const float ANGLE = 90.0;

vec3 palette(float t) {
    vec3 a = vec3(-4.746, 2.317, 5.389);
    vec3 b = vec3(5.737, 2.168, 5.239);
    vec3 c = vec3(0.105, 0.097, 0.103);
    vec3 d = vec3(0.917, 0.530, 0.454);
    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);
}

[
  [-4.746, 2.317, 5.389],
  [5.737, 2.168, 5.239],
  [0.105, 0.097, 0.103],
  [0.917, 0.530, 0.454]
]

Gradient palette editor — #3a305e to #efcd7b