Olive Drab (#6B8E23)

/* Background */
.element {
    background-color: #6B8E23;
}

/* Text */
.element {
    color: #6B8E23;
}

/* Border */
.element {
    border: 1px solid #6B8E23;
}

/* Linear gradient to complementary */
.element {
    background: linear-gradient(
        to right,
        #6B8E23,
        #7139E3
    );
}

/* Radial gradient */
.element {
    background: radial-gradient(
        circle,
        #6B8E23,
        #7139E3
    );
}

// SCSS variable
$olive-drab: #6B8E23;

// With RGB channels (useful for rgba() usage)
$olive-drab-r: 107;
$olive-drab-g: 142;
$olive-drab-b: 35;

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