css - 如何三 Angular 形顶部和底部边框？

Question

正如您在下图中看到的那样，我试图从底部和顶部扭曲或三 Angular 化我的 div，但我不知道该怎么做。我只是尝试了几次，但我无法达到结果。那么我怎样才能在伪装之前使用它呢？用 psuedo 制作没关系，但我想知道该怎么做？

这是我的代码:

body{
background:lightblue;;
}
.block{
    background-image: linear-gradient(to right, #314b56, #283b44, #1f2c32, #161e21, #0a0f11);
    border: 1px solid #fff;
    width: 300px;
    height: 150px;
    margin: 30px;
}

<div class="block"></div>

Answer 1

使用转换和透视的想法，您将在其中拥有边框、边框半径和渐变:

body {
  background: lightblue;
}

.block {
  overflow: hidden;
  width: 300px;
  height: 200px;
  margin: 20px;
  position: relative;
  z-index:0;
}

.block::before,
.block::after {
  content: "";
  position: absolute;
  z-index:-1;
  border: 1px solid #fff;
  top: 0;
  bottom: 0;
  width: 50%;
  background-image: linear-gradient(to right, #314b56, #283b44, #1f2c32, #161e21, #0a0f11);
  background-size: 200% 100%;
}

.block::before {
  left: 0;
  border-right: 0;
  border-radius: 15px 0 0 15px;
  transform-origin: right;
  transform: perspective(100px) rotateY(-5deg);
}

.block::after {
  right: 0;
  border-left: 0;
  border-radius: 0 15px 15px 0;
  transform-origin: left;
  transform: perspective(100px) rotateY(5deg);
  background-position: right;
}

<div class="block"></div>

您还可以添加阴影并轻松更改渐变:

body {
  background: lightblue;
}

.block {
  overflow: hidden;
  width: 300px;
  height: 200px;
  margin: 20px;
  position: relative;
  z-index:0;
  filter:drop-shadow(0 0 5px #000);
}

.block::before,
.block::after {
  content: "";
  position: absolute;
  z-index:-1;
  border: 1px solid #fff;
  top: 0;
  bottom: 0;
  width: 50%;
  background-image: linear-gradient(35deg, blue, red);
  background-size: 200% 100%;
}

.block::before {
  left: 0;
  border-right: 0;
  border-radius: 15px 0 0 15px;
  transform-origin: right;
  transform: perspective(100px) rotateY(-5deg);
}

.block::after {
  right: 0;
  border-left: 0;
  border-radius: 0 15px 15px 0;
  transform-origin: left;
  transform: perspective(100px) rotateY(5deg);
  background-position: right;
}

<div class="block"></div>