在 parent 上使用倾斜会导致 sidenav 失去位置

Question

抱歉措辞不当，我不确定该如何措辞。

我有一个 header 和一个容器，其中包含一个 sidenav 和用于切换它的按钮。我试图通过向相反方向倾斜来倾斜 header ，同时保持容器正常。然而，这样做会导致 sidenav 失去它的 height:100% 并且它不会粘在左边。

如何在不影响侧边的情况下倾斜背景？

这是 fiddle 和代码 https://jsfiddle.net/q0ddzw4v/

HTML

<body id="body">
    <header class="header">
        <div class="header__container">
            <div id="mySidenav" class="sidenav">
                <a href="javascript:void(0)" class="closebtn" onclick="closeNav()">&times;</a>
                <a href="#">About</a>
                <a href="#">Services</a>
                <a href="#">Clients</a>
                <a href="#">Contact</a>
            </div>

            <div id="main">
                <h2>Sidenav Push Example</h2>
                <p>Click on the element below to open the side navigation menu, and push this content to the right.</p>
                <span style="font-size:30px;cursor:pointer" onclick="openNav()">&#9776; open</span>
            </div>
        </div>
    </header>

    <script>
        function openNav() {
            document.getElementById("mySidenav").style.width = "250px";
        }

        function closeNav() {
            document.getElementById("mySidenav").style.width = "0";
        }
    </script>
</body>

CSS

body {
    font-family: sans-serif;
}

.sidenav {
    height: 100%;
    width: 0;
    position: fixed;
    z-index: 1;
    top: 0;
    left: 0;
    background-color: #111;
    overflow-x: hidden;
    transition: 0.5s;
    padding-top: 60px;
}

.sidenav a {
    padding: 8px 8px 8px 32px;
    text-decoration: none;
    font-size: 25px;
    color: #818181;
    display: block;
}

.sidenav a:hover,
.offcanvas a:focus {
    color: #f1f1f1;
}

.sidenav .closebtn {
    position: absolute;
    top: 0;
    right: 25px;
    font-size: 36px;
    margin-left: 50px;
}

#main {
    padding: 16px;
}

.header {
    width: 100%;
    height: 100vh;
    background-color: #C18D8D;
    transform: skewY(-10deg);
}

.header__container {
    width: 80%;
    max-width: 71.25rem;
    margin: auto;
    display: flex;
    flex-direction: column;
    height: 100%;
    transform: skewY(10deg);
}

Answer 1

不是倾斜 .header 容器，而是添加一个伪元素并倾斜它：

body {
  font-family: "Lato", sans-serif;
  transition: margin-left 0.5s;
}

.sidenav {
  height: 100%;
  width: 0;
  position: fixed;
  z-index: 1;
  top: 0;
  left: 0;
  background-color: #111;
  overflow-x: hidden;
  transition: 0.5s;
  padding-top: 60px;
}

.sidenav a {
  padding: 8px 8px 8px 32px;
  text-decoration: none;
  font-size: 25px;
  color: #818181;
  display: block;
}

.sidenav a:hover,
.offcanvas a:focus {
  color: #f1f1f1;
}

.sidenav .closebtn {
  position: absolute;
  top: 0;
  right: 25px;
  font-size: 36px;
  margin-left: 50px;
}

#main {
  transition: margin-left .5s;
  padding: 16px;
}

.header {
  position: relative;
  width: 100%;
  height: 100vh;
}

.header::before {
  display: block;
  position: absolute;
  width: 100%;
  height: 100%;
  background-color: #C18D8D;
  transform: skewY(-10deg);
  content: '';
}

.header__container {
  position: relative;
  z-index: 0;
  width: 80%;
  max-width: 71.25rem;
  margin: auto;
  display: flex;
  flex-direction: column;
  height: 100%;
}

<header class="header">
  <div class="header__container">
    <div id="mySidenav" class="sidenav">
      <a href="javascript:void(0)" class="closebtn" onclick="closeNav()">&times;</a>
      <a href="#">About</a>
      <a href="#">Services</a>
      <a href="#">Clients</a>
      <a href="#">Contact</a>
    </div>

    <div id="main">
      <h2>Sidenav Push Example</h2>
      <p>Click on the element below to open the side navigation menu, and push this content to the right.</p>
      <span style="font-size:30px;cursor:pointer" onclick="openNav()">&#9776; open</span>
    </div>
  </div>
</header>

<script>
  function openNav() {
    document.getElementById("mySidenav").style.width = "250px";
    // document.getElementById("body").style.marginLeft = "250px";
  }

  function closeNav() {
    document.getElementById("mySidenav").style.width = "0";
    // document.getElementById("body").style.marginLeft = "0";
  }
</script>

在 parent 上使用倾斜会导致 sidenav 失去位置

Using skew on parent causes sidenav to lose position

css

position

transform

absolute

skew