CSS设计 - 彩虹

Question

我想仅使用CSS创建彩虹.以下是所需内容的图像.

这是我的代码(到目前为止):

* {
  margin: 0;
  padding: 0;
}
#r {
  height: 80vw;
  width: 80vw;
  background-color: #f00;
  position: absolute;
  z-index: 1;
}
#o {
  height: 76vw;
  width: 76vw;
  background-color: #fe6230;
  position: absolute;
  top: 2vw;
  left: 2vw;
  z-index: 2;
}
#y {
  height: 72vw;
  width: 72vw;
  background-color: #fef600;
  position: absolute;
  top: 4vw;
  left: 4vw;
  z-index: 3;
}
#g {
  height: 68vw;
  width: 68vw;
  background-color: #00bc00;
  position: absolute;
  top: 6vw;
  left: 6vw;
  z-index: 4;
}
#b {
  height: 64vw;
  width: 64vw;
  background-color: #0048fe;
  position: absolute;
  top: 8vw;
  left: 8vw;
  z-index: 5;
}
#i {
  height: 60vw;
  width: 60vw;
  background-color: #000083;
  position: absolute;
  top: 10vw;
  left: 10vw;
  z-index: 6;
}
#v {
  height: 56vw;
  width: 56vw;
  background-color: #30009b;
  position: absolute;
  top: 12vw;
  left: 12vw;
  z-index: 7;
}

<div id="r">
</div>
<div id="o">
</div>
<div id="y">
</div>
<div id="g">
</div>
<div id="b">
</div>
<div id="i">
</div>
<div id="v">
</div>

我的代码的问题是我无法弯曲它(就像在真正的彩虹中).我还需要隐藏这条彩虹的一半.

Answer 1

这可以使用div带有:pseudo-element和的单个元素来完成box-shadow.

div {
  position: relative;
  width: 300px;
  height: 150px;
  background: white;
  overflow: hidden;
  transform: scale(2);
  margin-left: 130px;
  margin-top: -50px;
}
div:after {
  position: absolute;
  content: '';
  width: 100px;
  height: 100px;
  top: 100px;
  left: 50px;
  border-radius: 50%;
  box-shadow: 0 0 0 5px #4200AB, 0 0 0 10px #000095, 0 0 0 15px #00ABFF, 0 0 0 20px #00C800, 0 0 0 25px #FFF800, 0 0 0 30px #FF7642, 0 0 0 35px #E40000;
}

<div></div>

使用vh/ vwunits的示例.

Demo on CodePen

由于视口比率,在此处的代码段看起来很糟糕,在CodePen上查看效果更好.

div {
  position: relative;
  width: 95vw;
  height: 45vw;
  overflow: hidden;
  background: transparent;
  transform: translate(-50vw, -16.666vw);
  top: 8vw;
  left: 50vw;
}
div:after {
  position: absolute;
  content: '';
  width: 50%;
  height: 100%;
  top: 25vw;
  left: 25vw;
  border-radius: 50%;
  box-shadow: 0 0 0 2vw #4200AB, 0 0 0 4vw #000095, 0 0 0 6vw #00ABFF, 0 0 0 8vw #00C800, 0 0 0 10vw #FFF800, 0 0 0 12vw #FF7642, 0 0 0 14vw #E40000;
}
body {
  margin: 0;
}

<div></div>

Answer 2

这是一种略有不同的方法radial-gradient.该方法几乎是自我解释的,因为渐变背景以椭圆形方式应用,具有多个颜色停止(每个颜色一个,开始和结束时为白色).

注:该浏览器支持是多的好box-shadow绝对比radial-gradients,因此张贴chipChocolate.py答案很可能是最好的了.

这个也可以支持vw/vh单位并且可以相应地调整外观.

.rainbow {
  height: 25vw;
  width: 50vw;
  background: -webkit-radial-gradient(50% 110%, ellipse, white 35%, violet 35%, violet 40%, indigo 40%, indigo 45%, blue 45%, blue 50%, green 50%, green 55%, yellow 55%, yellow 60%, orange 60%, orange 65%, red 65%, red 70%, white 70%);
  background: -moz-radial-gradient(50% 110%, ellipse, white 35%, violet 35%, violet 40%, indigo 40%, indigo 45%, blue 45%, blue 50%, green 50%, green 55%, yellow 55%, yellow 60%, orange 60%, orange 65%, red 65%, red 70%, white 70%);
  background: radial-gradient(ellipse at 50% 110%, white 35%, violet 35%, violet 40%, indigo 40%, indigo 45%, blue 45%, blue 50%, green 50%, green 55%, yellow 55%, yellow 60%, orange 60%, orange 65%, red 65%, red 70%, white 70%);
}

<div class="rainbow"></div>