如何解决导航滚动问题？

Question

我无法弄清楚我设计用来滚动y的菜单（如果它不在屏幕上）。

我尝试通过将overflow-y设置为auto来尝试，但是没有用。并设置高度会将导航移到顶部。

有关完整的示例代码，请使用code project url

任何解决该问题的帮助将不胜感激。

body{
  background: #CCC;
}
.knl-primary-nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: fixed;
    top: 0;
    left: 5%;
    right: 5%;
    height: 5em;
    line-height: 5em;
    width: inherit;
    max-width: inherit;
    margin: 0 auto;
    z-index: 999;
}

.knl-primary-nav .logo {
    background: white;
    padding: 0 1.5em;
    transform:skewX(20deg);
}

.knl-primary-nav .logo>* {
    display: block;
    transform: skew(-20deg);
}

.knl-primary-nav .logo h1 {
    height: 1em;
    width: auto;
    display: block;
}

.knl-primary-nav .toggle-icon,
.knl-primary-nav input[type=checkbox] {
    display: none;
    color: #e71715;
}

.knl-primary-nav ul {
    display: flex;
    justify-content: flex-end;
    padding: 0;
    list-style: none;
}

.knl-primary-nav ul>li>a{
  background: #FFFFFF;
  display: block;
  text-align: center;
  padding: 0 2em;
  color: #000000;
  text-decoration: none;
}

.knl-primary-nav>ul>li>a{
  transform: skewX(20deg);
}

.knl-primary-nav>ul>li>a>span{
  transform: skew(-20deg);
  display: block;
}

.knl-primary-nav ul li.current-menu-item a, .knl-primary-nav ul li a:hover{
  background: #e71715;
  color: #FFFFFF;
}

.knl-primary-nav>ul>li.current-menu-item>a, .knl-primary-nav>ul>li>a:hover{
  transform: skewX(20deg) scaleY(1.3);
}

.knl-primary-nav>ul>li.current-menu-item>a>span, .knl-primary-nav>ul>li>a:hover>span{
  transform: skewX(-20deg) scaleY(0.76);
}

.knl-primary-nav>ul>li>ul{
  position: absolute;
  display: none;
  flex-direction: column;
}
.knl-primary-nav>ul>li>ul>li{
  line-height: 2em;
}
.knl-primary-nav>ul>li.menu-item-has-children:hover>ul{
  display: flex;
}

.knl-primary-nav>ul>li>ul a:hover{
  background: #e71715;
  color: #FFF;
}

@media screen and (max-width:768px){
.knl-primary-nav {
        line-height: 1.5;
        height: 4em;
        /*line-height: 4em;*/
    }
    .knl-primary-nav .logo img {
        height: 4em;
    }
    .knl-primary-nav ul {
        display: none;
    }
    .knl-primary-nav .toggle-icon {
        display: inline-block;
        margin-bottom: 0;
    }
  
  input[type=checkbox]:checked~ul {
        position: absolute;
        top: 4.5em;
        display: flex;
        flex-direction: column;
        width: 100%;
        margin: 0 auto;
    }
    .knl-primary-nav>ul>li a,.knl-primary-nav>ul>li a:hover,
    .knl-primary-nav>ul>li.current-menu-item a{
        transform: skewX(0deg);
        line-height: 2em;
        text-align: left;
    }
    .knl-primary-nav>ul>li>ul{
      display:flex;
      position: relative;
    }
  .knl-primary-nav>ul>li>ul>li{
    list-style: 
  }
  .knl-primary-nav>ul>li>ul a{
    padding-left: 50px;
  }
}

<link href="https://use.fontawesome.com/releases/v5.6.3/css/all.css" rel="stylesheet"/>
<nav class="knl-primary-nav" style="background: transparent; left: 5%; right: 5%; padding: 0px;">
        <div class="logo">
          <a href="https://devs.kodenlogix.com/mtmgrp/mtmglobal"><h1>LOGO</h1></a>
        </div>
        <label for="navmenu" class="toggle-icon"><span><i class="fa fa-bars fa-3x"></i></span></label>
        <input type="checkbox" id="navmenu">
        <ul id="knl-primary-menu" class="menu"><li id="menu-item-18" class=""><a href="#"><span>Home</span></a></li>
<li class="current-menu-parent current_page_parent current_page_ancestor menu-item-has-children"><a href="#"><span>Link 1</span></a>
<ul class="sub-menu">
	<li><a href="#"><span>Sub Link 1</span></a></li>
	<li><a href="#"><span>Sub Link 2</span></a></li>
	<li><a href="#"><span>Sub Link 3</span></a></li>
</ul>
</li>
</ul>        </nav>

Answer 1

下面是导航栏移动菜单的解决方案。

body{
  background: #CCC;
}
.knl-primary-nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: fixed;
    top: 0;
    left: 5%;
    right: 5%;
    height: 5em;
    line-height: 5em;
    width: inherit;
    max-width: inherit;
    margin: 0 auto;
    z-index: 999;
}

.knl-primary-nav .logo {
    background: white;
    padding: 0 1.5em;
    transform:skewX(20deg);
}

.knl-primary-nav .logo>* {
    display: block;
    transform: skew(-20deg);
}

.knl-primary-nav .logo h1 {
    height: 1em;
    width: auto;
    display: block;
}

.knl-primary-nav .toggle-icon,
.knl-primary-nav input[type=checkbox] {
    display: none;
    color: #e71715;
}

.knl-primary-nav ul {
    display: flex;
    justify-content: flex-end;
    padding: 0;
    list-style: none;
}

.knl-primary-nav ul>li>a{
  background: #FFFFFF;
  display: block;
  text-align: center;
  padding: 0 2em;
  color: #000000;
  text-decoration: none;
}

.knl-primary-nav>ul>li>a{
  transform: skewX(20deg);
}

.knl-primary-nav>ul>li>a>span{
  transform: skew(-20deg);
  display: block;
}

.knl-primary-nav ul li.current-menu-item a, .knl-primary-nav ul li a:hover{
  background: #e71715;
  color: #FFFFFF;
}

.knl-primary-nav>ul>li.current-menu-item>a, .knl-primary-nav>ul>li>a:hover{
  transform: skewX(20deg) scaleY(1.3);
}

.knl-primary-nav>ul>li.current-menu-item>a>span, .knl-primary-nav>ul>li>a:hover>span{
  transform: skewX(-20deg) scaleY(0.76);
}

.knl-primary-nav>ul>li>ul{
  position: absolute;
  display: none;
  flex-direction: column;
}
.knl-primary-nav>ul>li>ul>li{
  line-height: 2em;
}
.knl-primary-nav>ul>li.menu-item-has-children:hover>ul{
  display: flex;
}

.knl-primary-nav>ul>li>ul a:hover{
  background: #e71715;
  color: #FFF;
}

@media screen and (max-width:768px){
.knl-primary-nav {
        line-height: 1.5;
        height: 4em;
        /*line-height: 4em;*/
    }
    .knl-primary-nav .logo img {
        height: 4em;
    }
    .knl-primary-nav ul {
        display: none;
    }
    .knl-primary-nav .toggle-icon {
        display: inline-block;
        margin-bottom: 0;
    }
  
  input[type=checkbox]:checked~ul {
        position: absolute;
        top: 4.5em;
        display: block;
        flex-direction: column;
        width: 100%;
        height:150px;
        margin: 0 auto;
        overflow-y:scroll;
    }
    .knl-primary-nav>ul>li a,.knl-primary-nav>ul>li a:hover,
    .knl-primary-nav>ul>li.current-menu-item a{
        transform: skewX(0deg);
        line-height: 2em;
        text-align: left;
    }
    .knl-primary-nav>ul>li>ul{
      display:flex;
      position: relative;
    }
  .knl-primary-nav>ul>li>ul>li{
    list-style: 
  }
  .knl-primary-nav>ul>li>ul a{
    padding-left: 50px;
  }
}

<link href="https://use.fontawesome.com/releases/v5.6.3/css/all.css" rel="stylesheet"/>
<nav class="knl-primary-nav" style="background: transparent; left: 5%; right: 5%; padding: 0px;">
        <div class="logo">
          <a href="https://devs.kodenlogix.com/mtmgrp/mtmglobal"><h1>LOGO</h1></a>
        </div>
        <label for="navmenu" class="toggle-icon"><span><i class="fa fa-bars fa-3x"></i></span></label>
        <input type="checkbox" id="navmenu">
        <ul id="knl-primary-menu" class="menu"><li id="menu-item-18" class=""><a href="#"><span>Home</span></a></li>
<li class="current-menu-parent current_page_parent current_page_ancestor menu-item-has-children"><a href="#"><span>Link 1</span></a>
<ul class="sub-menu">
	<li><a href="#"><span>Sub Link 1</span></a></li>
	<li><a href="#"><span>Sub Link 2</span></a></li>
	<li><a href="#"><span>Sub Link 3</span></a></li>
</ul>
</li>
</ul>        </nav>