Dark Yellow (#9B870C)

/* Background */
.element {
    background-color: #9B870C;
}

/* Text */
.element {
    color: #9B870C;
}

/* Border */
.element {
    border: 1px solid #9B870C;
}

/* Linear gradient to complementary */
.element {
    background: linear-gradient(
        to right,
        #9B870C,
        #3F59F7
    );
}

/* Radial gradient */
.element {
    background: radial-gradient(
        circle,
        #9B870C,
        #3F59F7
    );
}

// SCSS variable
$dark-yellow: #9B870C;

// With RGB channels (useful for rgba() usage)
$dark-yellow-r: 155;
$dark-yellow-g: 135;
$dark-yellow-b: 12;

// Usage
.element {
    background-color: $dark-yellow;
    color: rgba($dark-yellow-r, $dark-yellow-g, $dark-yellow-b, 0.8);
}