Cool Black (#002E63)

/* Background */
.element {
    background-color: #002E63;
}

/* Text */
.element {
    color: #002E63;
}

/* Border */
.element {
    border: 1px solid #002E63;
}

/* Linear gradient to complementary */
.element {
    background: linear-gradient(
        to right,
        #002E63,
        #C66A00
    );
}

/* Radial gradient */
.element {
    background: radial-gradient(
        circle,
        #002E63,
        #C66A00
    );
}

// SCSS variable
$cool-black: #002E63;

// With RGB channels (useful for rgba() usage)
$cool-black-r: 0;
$cool-black-g: 46;
$cool-black-b: 99;

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