1.rgba(red,green,blue,alpha（不透明度0.0（完全透明）与 1.0（完全不透明））
2.HSLa（hue（色调 0red 120green 240blue）,saturation（饱和度）,lightness（亮度）,alpha)颜色柱面坐标表示法
hue:Any angle, from 0 to 360, taken from a typical color wheel, where “0” (and “360”) is red, “120” is green and “240” is blue.
saturation:from 0% (none, so a level of grey depending on the lightness) to 100% (the whole whack,0% 意味着灰色，而 100% 是全彩。
lightness:From 0% (black) to 100% (white), 50% being “normal”.0% 是黑色，100% 是白色。