Smoky Black (#100C08)

/* Background */
.element {
    background-color: #100C08;
}

/* Text */
.element {
    color: #100C08;
}

/* Border */
.element {
    border: 1px solid #100C08;
}

/* Linear gradient to complementary */
.element {
    background: linear-gradient(
        to right,
        #100C08,
        #081018
    );
}

/* Radial gradient */
.element {
    background: radial-gradient(
        circle,
        #100C08,
        #081018
    );
}

// SCSS variable
$smoky-black: #100C08;

// With RGB channels (useful for rgba() usage)
$smoky-black-r: 16;
$smoky-black-g: 12;
$smoky-black-b: 8;

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