将阴影和z索引应用于绝对定位元素

Question

我试图在导航栏中实现一个凸起，导航条应该有一个方框-阴影.然而，在底部也需要它.不知何故，我不能把撞在导航栏后面，这是一个已知的问题，还是我遗漏了什么？非常感谢。

​

body {
  background: beige;
}

.c-header {
  background: white;
  box-shadow: 0 2px 2px rgba(0, 0, 0, 0.8);
  height: 60px;
  position: fixed;
  width: 100%;
  z-index: 9999;
}

.c-site-nav {
  align-content: center;
  display: flex;
  justify-content: space-between;
}
.c-site-nav ul {
  margin-left: 0;
}
.c-site-nav__item {
  display: flex;
  justify-content: space-around;
  list-style: none;
  width: 40%;
}
.c-site-nav__item a {
  font-size: 20px;
  color: grey;
  display: inline-block;
  text-decoration: none;
}

.c-logo {
  position: absolute;
  left: 50%;
  transform: translate(-50%, 0);
  padding: 0;
  position: absolute;
  top: 15px;
  width: 45px;
  z-index: 1;
}
.c-logo::after {
  box-shadow: 0 2px 2px rgba(0, 0, 0, 0.8);
  position: absolute;
  left: 50%;
  transform: translate(-50%, 0);
  background: white;
  border-radius: 50%;
  content: '';
  height: 60px;
  position: absolute;
  width: 60px;
  z-index: -100;
}

<header class="c-header">
  <div class="c-logo">
  </div>
  <nav class="c-site-nav">
    <ul class="c-site-nav__item">
        <li><a href="/">asd</a></li>
        <li><a href="/ueber_uns">asd</a></li>
        <li><a href="/">asd</a></li>
    </ul>
    <ul class="c-site-nav__item">
        <li><a href="/">asd</a></li>
        <li><a href="/">asd</a></li>
        <li><a href="tel:+49234234234">34234234</a></li>
    </ul>
  </nav>
</header>

​

Answer 1

不好意思，我刚刚意识到了最简单的实现方法，那就是在这个伪元素的上面加上另一个伪元素，这样就可以消除(或掩盖)凸起的阴影。

​

body {
  background: beige;
  margin: 0;
}

.c-header {
  box-shadow: 0 1.5px 4px rgba(0, 0, 0, 0.24), 0 1.5px 6px rgba(0, 0, 0, 0.12);
  background: white;
  height: 45px;
  width: 100%;
  z-index: 9999;
}

.c-site-nav {
  align-content: center;
  display: flex;
  justify-content: space-between;
}
.c-site-nav ul {
  margin-left: 0;
}
.c-site-nav__item {
  display: flex;
  justify-content: space-around;
  list-style: none;
  width: 40%;
}
.c-site-nav__item a {
  font-size: 20px;
  color: grey;
  display: inline-block;
  text-decoration: none;
}

.c-logo {
  position: absolute;
  left: 50%;
  transform: translate(-50%, 0);
  padding: 0;
  position: absolute;
  top: 10px;
  width: 45px;
  z-index: 1;
}
.c-logo::after {
  box-shadow: 0 1.5px 4px rgba(0, 0, 0, 0.24), 0 1.5px 6px rgba(0, 0, 0, 0.12);
  background: white;
  border-radius: 50%;
  position: absolute;
  left: 50%;
  transform: translate(-50%, 0);
  content: '';
  height: 45px;
  position: absolute;
  width: 60px;
  z-index: -1;
}

.c-logo::before {
  background: white;
  position: absolute;
  left: 50%;
  transform: translate(-50%, 0);
  content: '';
  top: -10px;
  height: 45px;
  position: absolute;
  width: 80px;
  z-index: 1;
}

<header class="c-header">
  <div class="c-logo">
</div>
  <nav class="c-site-nav">
    <ul class="c-site-nav__item">
      <li><a href="/">item</a></li>
      <li><a href="/">item</a></li>
      <li><a href="/">item</a></li>
    </ul>
    <ul class="c-site-nav__item">
      <li><a href="/">item</a></li>
      <li><a href="/">item</a></li>
      <li><a href="/">item</a></li>
    </ul>
  </nav>
</header>

​

Answer 2

我不知道这是否是预期的结果，但我成功地通过将

  <div class="c-logo">

在标头元素的外部。

​

body {
  background: beige;
}

.c-header {
  background: white;
  box-shadow: 0 2px 2px rgba(0, 0, 0, 0.8);
  height: 60px;
  position: fixed;
  width: 100%;
  z-index: 9999;
}

.c-site-nav {
  align-content: center;
  display: flex;
  justify-content: space-between;
}
.c-site-nav ul {
  margin-left: 0;
}
.c-site-nav__item {
  display: flex;
  justify-content: space-around;
  list-style: none;
  width: 40%;
}
.c-site-nav__item a {
  font-size: 20px;
  color: grey;
  display: inline-block;
  text-decoration: none;
}

.c-logo {
  position: absolute;
  left: 50%;
  transform: translate(-50%, 0);
  padding: 0;
  position: absolute;
  top: 15px;
  width: 45px;
  z-index: 1;
}
.c-logo::after {
  box-shadow: 0 2px 2px rgba(0, 0, 0, 0.8);
  position: absolute;
  left: 50%;
  transform: translate(-50%, 0);
  background: white;
  border-radius: 50%;
  content: '';
  height: 60px;
  position: absolute;
  width: 60px;
  z-index: -100;
}

<header class="c-header">
  </div>
  <nav class="c-site-nav">
    <ul class="c-site-nav__item">
        <li><a href="/">asd</a></li>
        <li><a href="/ueber_uns">asd</a></li>
        <li><a href="/">asd</a></li>
    </ul>
    <ul class="c-site-nav__item">
        <li><a href="/">asd</a></li>
        <li><a href="/">asd</a></li>
        <li><a href="tel:+49234234234">34234234</a></li>
    </ul>
  </nav>
</header>
  <div class="c-logo">

​

Answer 3

您已经为box-shadow circle指定了伪选择器:after上的blur-radius，您可以将该特定元素上的blur-radius缩减如下，

方框-阴影:偏移-x，偏移-y，模糊-半径-颜色

​

body {
  background: beige;
}

.c-header {
  background: white;
  box-shadow: 0 2px 2px -2px rgba(0, 0, 0, 0.8);
  height: 60px;
  position: fixed;
  width: 100%;
  z-index: 9999;
}

.c-site-nav {
  align-content: center;
  display: flex;
  justify-content: space-between;
}
.c-site-nav ul {
  margin-left: 0;
}
.c-site-nav__item {
  display: flex;
  justify-content: space-around;
  list-style: none;
  width: 40%;
}
.c-site-nav__item a {
  font-size: 20px;
  color: grey;
  display: inline-block;
  text-decoration: none;
}

.c-logo {
  position: absolute;
  left: 50%;
  transform: translate(-50%, 0);
  padding: 0;
  position: absolute;
  top: 15px;
  width: 45px;
  z-index: 1;
}
.c-logo::after {
  box-shadow: 0 2px 2px -2px rgba(0, 0, 0, 0.8);
  position: absolute;
  left: 50%;
  transform: translate(-50%, 0);
  background: white;
  border-radius: 50%;
  content: '';
  height: 60px;
  position: absolute;
  width: 60px;
  z-index: -100;
}

<header class="c-header">
  <div class="c-logo">
  </div>
  <nav class="c-site-nav">
    <ul class="c-site-nav__item">
        <li><a href="/">asd</a></li>
        <li><a href="/ueber_uns">asd</a></li>
        <li><a href="/">asd</a></li>
    </ul>
    <ul class="c-site-nav__item">
        <li><a href="/">asd</a></li>
        <li><a href="/">asd</a></li>
        <li><a href="tel:+49234234234">34234234</a></li>
    </ul>
  </nav>
</header>

​