html - 如何在纯CSS中使伪元素具有相同的高度和宽度？

Question

.speech 的高度可能会有所不同，因此寻找使 .speech::after 的宽度与 .speech 的宽度相同的解决方案高度。

理想的结果

body {
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
}

.speech {
  width: 250px;
  padding: 1rem;
  background-color: tomato;
  color: white;
  border: 1px solid;
  position: relative;
}

.speech::after {
  content: '';
  position: absolute;
  top: 0;
  left: 100%;
  border: 3px solid deepskyblue;
  height: 100%;
  padding-left: 50%;
  background: linear-gradient(45deg, transparent 50%, green 0%);
  transform: translateX(-50%) rotate(45deg);
}

<div class="speech">Lorem ipsum dolor sit amet consectetur adipisicing elit. Facilis minima possimus, maxime, fugit dolorum optio, tempora et doloribus doloremque ullam inventore repellendus veniam modi quasi iusto numquam amet eos! Exercitationem.</div>

Answer 1

你不一定需要伪元素，只要你使用 CSS 渐变，因为所有支持渐变的浏览器也支持多背景:

body {
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
}

.speech {
  width: 250px;
  padding: 1rem;
  background: linear-gradient(tomato,tomato),
              linear-gradient(to top right, tomato 49%,transparent 51%),
              linear-gradient(to bottom right, tomato 49%,transparent 51%);
  background-size: calc(100% - 30px) 100%, 30px 50%, 30px 50%;
  background-position: 0 0, 100% 0, 100% 100%;
  background-repeat: no-repeat;
  color: white;
  border: 1px solid;
  position: relative;
}

<div class="speech">Lorem ipsum dolor sit amet consectetur adipisicing elit. Facilis minima possimus, maxime, fugit dolorum optio, tempora et doloribus doloremque ullam inventore repellendus veniam modi quasi iusto numquam amet eos! Exercitationem.</div>