This is my html code, and the lower one is css code. I really need help :( :hover class does not work at all. Did I code something wrong?

html {
  box-sizing: border-box;
}

a {
  text-decoration: none;
  color: black;
}

.nav_bar>li {
  padding: 20px;
  flex-basis: 0;
  flex-grow: 1;
  background-color: #ffffa8;
  height: 1rem;
  text-align: center;
  flex-direction: column;
}

#Homesub {
  display: none;
}

#Home:hover #Homesub {
  display: list-item;
}

<nav>
  <ul class="nav_bar">
    <li>
      <a href="Hme.html" id="Home">Home</a>
      <ul class="sub">
        <li><a href="Members.html" id="Homesub">Members</a></li>
      </ul>
    </li>
  </ul>
</nav>

<iframe name="sif1" sandbox="allow-forms allow-modals allow-scripts" frameborder="0"></iframe>

CodePudding user response：

You are targeting the anchor, not the li

Seems like you should be targeting the ul.

html {
  box-sizing: border-box;
}

a {
  text-decoration: none;
  color: black;
}

.nav_bar>li {
  padding: 20px;
  flex-basis: 0;
  flex-grow: 1;
  background-color: #ffffa8;
  height: 1rem;
  text-align: center;
  flex-direction: column;
}

li > ul {
  display: none;
}

li:hover > ul {
  display: block;
}

<nav>
  <ul class="nav_bar">
    <li>
      <a href="Hme.html" id="Home">Home</a>
      <ul class="sub">
        <li><a href="Members.html" id="Homesub">Members</a></li>
      </ul>
    </li>
  </ul>
</nav>

<iframe name="sif2" sandbox="allow-forms allow-modals allow-scripts" frameborder="0"></iframe>

CodePudding user response：

* {
    list-style: none;
    text-decoration: none;
    padding: 0;
    margin: 0;
}

nav {
    width: auto;
    display: flex;
    justify-content: center;
}

nav > ul > li {
    background-color: #ddd;
    padding: 10px 20px;
    text-transform: uppercase;
    position: relative;
}

nav > ul > li > a   ul {
    display: none;
    position: absolute;
    left: 0;
    top: 100%;
    background-color: rgb(243 243 243);
    width: 100%;
    text-align: center;
    padding: 10px;
}

nav > ul > li:hover > a   ul {
    display: initial;
}

<nav>
  <ul class="nav_bar">
    <li>
      <a href="Hme.html" id="Home">Home</a>
      <ul class="sub">
        <li>
          <a href="Members.html" id="Homesub">Members</a>
          </li>
      </ul>
    </li>
  </ul>
</nav>

<iframe name="sif3" sandbox="allow-forms allow-modals allow-scripts" frameborder="0"></iframe>