Canary Yellow (#FFEF00)

/* Background */
.element {
    background-color: #FFEF00;
}

/* Text */
.element {
    color: #FFEF00;
}

/* Border */
.element {
    border: 1px solid #FFEF00;
}

/* Linear gradient to complementary */
.element {
    background: linear-gradient(
        to right,
        #FFEF00,
        #0010FF
    );
}

/* Radial gradient */
.element {
    background: radial-gradient(
        circle,
        #FFEF00,
        #0010FF
    );
}

// SCSS variable
$canary-yellow: #FFEF00;

// With RGB channels (useful for rgba() usage)
$canary-yellow-r: 255;
$canary-yellow-g: 239;
$canary-yellow-b: 0;

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