src/Types/HSL.php
public function darken($pct)
    {
        $lightness = $this->lightness() - $pct;
        $lightness = $lightness < 0 ? 0 : $lightness;

        return $this->withLightness($lightness);
    }
public function darken($pct)
    {
        $lightness = $this->lightness() - $pct;
        $lightness = $lightness < 0 ? 0 : $lightness;

        return $this->withLightness($lightness);
    }
Darken the color.

@param int $pct

@return static