css - 为什么我的下拉菜单出现在正文背景图片后面？

Question

我在每个类别下构建了一个带有下拉菜单的水平菜单。我知道一般来说我的网站编码是杂乱无章的，但主要问题是为什么下拉菜单被我页面主要内容上方的包装器遮住了。在 jsfiddle 中，它将位于“乌干达”后面并延伸到整个页面。然而，每当我打开一个下拉菜单时，尽管它在我的 css 中被归类为背景图像，但下拉菜单仍位于包装器后面。

https://jsfiddle.net/pr8kexmt/

a {
  text-decoration: none;
  display: block;
  padding: 12px 16px;
}

body {
  margin: 0px;
  overflow-x: hidden;
}

.bodycontent {
  z-index: -1;
}

.content {
  font-family: verdana;
  font-size: 30px;
}

.donate {
  background-color: orange;
  border: white;
  color: rgb(255, 255, 255);
  padding: 7px 14px;
  font-size: 15px;
  border-radius: 8px;
}

.donate:hover {
  background-color: rgb(102, 51, 0);
  color: rgb(255, 255, 255);
}

.divnav {
  width: 100%;
  overflow: hidden;
}

.dropdown {
  position: relative;
  display: inline-block;
}

.dropbtn {
  font-size: 13px;
  border: none;
  outline: none;
  background-color: inherit;
  float: right;
  display: block;
  margin: 3px 3px 3px 3px;
  font-family: verdana;
  font-weight: 550;
}

.dropbtn:hover {
  color: orange;
}

.dropdown-content {
  display: none;
  position: absolute;
  background-color: #f9f9f9;
  min-width: 160px;
  box-shadow: 0px 8px 16px 0px rgba(0, 0, 0, 0.2);
  z-index: 1;
  overflow: auto;
  top: 100%;
}

.dropdown-contentblock {
  height: 20px;
}

.dropdown:hover .dropdown-content {
  display: block;
}

html {}

.image {
  overflow: hidden;
}

.navbar {
  width: 80%;
  margin-left: auto;
  margin-right: auto;
  text-align: center;
}

.navelement {
  float: right;
  display: block;
  margin: 3px 3px 3px 3px;
  font-family: verdana;
  font-size: 13px;
  font-weight: 550;
}

.nava {
  padding: 5px;
}

.nava:hover {
  background-color: white;
  color: orange;
}

.pagetitle {
  height: 68px;
  width: 100%;
  background-image: url("pictures/titlebar1.jpg");
  z-index: -10;
}

.par {
  /* DIV THAT GOES UNDER TODOCONTENT ONLY AND MARKS A PARAGRAPH WITH INFORMATIVE CONTENT*/
}

.parcontent {
  font-family: verdana;
  color: rgb(150, 150, 150);
  font-size: 15px;
}

.titleimage {
  overflow: hidden;
  height: 310px;
  margin: 0px;
  width: 100%;
}

.title {
  font-family: verdana;
  font-size: 50px;
  color: white;
}

.todocontent {
  width: 47%;
  /* A DIV WITH CLASS TODOCONTENT MEANS A DIV THAT WILL CONTAIN ALL INFORMATIVE CONTENT OF THE PAGE*/
}

.wrapper {
  width: 100%;
  height: 5%;
  overflow: hidden;
}

<div class="titleimage">
  <img src="file:///Users/kirannairrl/Desktop/KiranNairRL/internship/current/pictures/heading2.jpg" alt="GLI.logo" style="width:100%;height:100%;">
</div>
<div class="divnav">
  <div class="wrapper" style="POSITION: absolute; TOP: 300px; LEFT: 0px;">
    <img src="file:///Users/kirannairrl/Desktop/KiranNairRL/internship/current/pictures/wrapper.png" alt="wrapper" style="width:20000px;height:5px;">
  </div>
  <div style="POSITION: relative; TOP: 20px; LEFT: 15%;">
    <img src="file:///Users/kirannairrl/Desktop/KiranNairRL/internship/current/pictures/GLI.logo.png" alt="GLI.logo" style="width:145px;height:152px;">
  </div>
  <div style="POSITION: relative; TOP: -50px; LEFT: 10%;">
    <ul class="navbar">
      <div class="dropdown">
        <button class="dropbtn">HOME</button>
        <!--<div class="dropdown-content">
					<a href="#">HOME</a>
				</div>-->
      </div>
      <div class="dropdown">
        <button class="dropbtn">ABOUT</button>
        <div class="dropdown-content">
          <a href="#">Vision & Mission</a>
          <a href="#">What We Do</a>
          <a href="#">Our Story</a>
          <a href="#">GLI Leadership</a>
          <a href="#">Academic Partners</a>
          <a href="#">Annual Report</a>
        </div>
      </div>
      <div class="dropdown">
        <button class="dropbtn">PROGRAMS</button>
        <div class="dropdown-content">
          <a href="#">Immersion Trips</a>
          <a href="#">Internships</a>
          <a href="#">IKnow Concert Series</a>
          <a href="#">Women's Leadership Retreat</a>
          <a href="#">Youth Summit</a>
        </div>
      </div>
      <div class="dropdown">
        <button class="dropbtn">ENTUSI</button>
        <div class="dropdown-content">
          <a href="#">About Entusi</a>
          <a href="#">Entusi Leadership</a>
        </div>
      </div>
      <div class="dropdown">
        <button class="dropbtn">MEDIA</button>
        <div class="dropdown-content">
          <a href="#">Press</a>
          <a href="#">Blog</a>
          <a href="#">Videos</a>
        </div>
      </div>
      <div class="dropdown">
        <button class="dropbtn">UPCOMING EVENTS</button>
        <!--<div class="dropdown-content">
					<a href="#">UPCOMING EVENTS</a>
				</div>-->
      </div>
      <div class="dropdown">
        <button class="dropbtn">TRIP PREP</button>
        <div class="dropdown-content">
          <a href="#">Orientational Materials</a>
          <a href="#">F.A.Q.</a>
        </div>
      </div>
      <div class="dropdown">
        <button class="dropbtn">RESEARCH</button>
        <div class="dropdown-content">
          <a href="#">Articles</a>
          <a href="#">Capstones</a>
        </div>
      </div>
      <div class="dropdown">
        <button class="dropbtn">CONTACT</button>
        <!--<div class="dropdown-content">
					<a href="#">CONTACT</a>
				</div>-->
      </div>
    </ul>
  </div>
  <div class="divdonate" style="POSITION: relative; TOP: -140px; LEFT: 80%;">
    <button class="donate">DONATE NOW</button>
  </div>
</div>

<body>

  <div class="bodycontent">
    <div class="pagetitle">
      <div>
        <header class="title" style="POSITION: relative; LEFT: 15%">Uganda</header>
      </div>
    </div>
    <div class="todocontent" style="POSItiON: relative; TOP: 15%; LEFT: 15%;">
      <div class="par" style="POSITION: relative; TOP: 15%; LEFT: 0%;">
        <p class="parcontent">
          Uganda was formed from the colonization of the Buganda Kingdom by the British in the 19th century. Britain wanted to protect the viability of the Nile River for its trading potential which prompted the British government to annex Buganda to create the
          Uganda Protectorate in 1894. In 1962 Uganda regained its independence and declared itself a republic with Milton Obote as the first prime minister and former Bugandan King Muteesa as the president. Despite being largely ceremonial, Obote removed
          the presidential position and established a new constitution in which he became a powerful president similar to a dictator. After committing many atrocities Obote was removed from power in a coup orchestrated by General Idi Amin who seized control
          of the country. Amin proceeded to be nearly as atrocious as Obote when almost 500,000 citizens perished under his regime. Despite entering presidency with cheers, his actions made the country of Uganda hate him. After Amin was removed from power
          by largely Tanzanian forces, Obote returned to presidency. A war broke out as a result from the election resulting in the deaths of between 100 and 500,000 people. This compelled 2 military commanders to conduct a coup in which Museveni gained
          control. Yoweri Museveni remains in power till this date.
        </p>
      </div>
    </div>
  </div>

Answer 1

因为这个

.divnav {
    width: 100%;
    overflow: hidden;
}

真的需要溢出隐藏吗？如果你删除它，工作正常