Dark Cyan (#008B8B)

/* Background */
.element {
    background-color: #008B8B;
}

/* Text */
.element {
    color: #008B8B;
}

/* Border */
.element {
    border: 1px solid #008B8B;
}

/* Linear gradient to complementary */
.element {
    background: linear-gradient(
        to right,
        #008B8B,
        #FF1717
    );
}

/* Radial gradient */
.element {
    background: radial-gradient(
        circle,
        #008B8B,
        #FF1717
    );
}

// SCSS variable
$dark-cyan: #008B8B;

// With RGB channels (useful for rgba() usage)
$dark-cyan-r: 0;
$dark-cyan-g: 139;
$dark-cyan-b: 139;

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