Dark Scarlet (#560319)

/* Background */
.element {
    background-color: #560319;
}

/* Text */
.element {
    color: #560319;
}

/* Border */
.element {
    border: 1px solid #560319;
}

/* Linear gradient to complementary */
.element {
    background: linear-gradient(
        to right,
        #560319,
        #03A97D
    );
}

/* Radial gradient */
.element {
    background: radial-gradient(
        circle,
        #560319,
        #03A97D
    );
}

// SCSS variable
$dark-scarlet: #560319;

// With RGB channels (useful for rgba() usage)
$dark-scarlet-r: 86;
$dark-scarlet-g: 3;
$dark-scarlet-b: 25;

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