Forest Green (#228B22)

/* Background */
.element {
    background-color: #228B22;
}

/* Text */
.element {
    color: #228B22;
}

/* Border */
.element {
    border: 1px solid #228B22;
}

/* Linear gradient to complementary */
.element {
    background: linear-gradient(
        to right,
        #228B22,
        #E333E3
    );
}

/* Radial gradient */
.element {
    background: radial-gradient(
        circle,
        #228B22,
        #E333E3
    );
}

// SCSS variable
$forest-green: #228B22;

// With RGB channels (useful for rgba() usage)
$forest-green-r: 34;
$forest-green-g: 139;
$forest-green-b: 34;

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