添加z-index后双导航栏（navbar）响应式失效问题排查求助

Hey folks, I tried posting this issue earlier but didn’t provide enough details, so I’m back with a clearer breakdown of what’s going on.

My website has two navbars: one for main site navigation, and a second dedicated to the comics section. Both were fully responsive—collapsing into hamburger menus on mobile, expanding properly when toggled—until I added z-index properties to them. Now the responsive functionality is completely broken; the hamburger toggles don’t trigger menu expansion, and the navbars refuse to adjust correctly on smaller screens.

I’m almost certain the z-index changes are the culprit, but I can’t pinpoint exactly how they’re interfering with the responsive behavior. Below is the full HTML/PHP for the site header (containing both navbars) and the corresponding CSS that styles them, including the z-index values I added. Any help troubleshooting or fixing this would be a huge lifesaver!

HTML/PHP (Site Header) #

<!-- Replace with your actual code; example structure provided -->
<header>
  <!-- Main Site Navbar -->
  <nav class="main-navbar">
    <div class="container">
      <a href="/" class="site-brand">My Website</a>
      <button class="main-toggle" aria-label="Toggle main navigation">☰</button>
      <div class="main-nav-links">
        <a href="/about">About</a>
        <a href="/blog">Blog</a>
        <a href="/contact">Contact</a>
      </div>
    </div>
  </nav>

  <!-- Comics Section Navbar -->
  <nav class="comics-navbar">
    <div class="container">
      <a href="/comics" class="comics-brand">Comics Library</a>
      <button class="comics-toggle" aria-label="Toggle comics navigation">☰</button>
      <div class="comics-nav-links">
        <a href="/comics/latest">Latest Issues</a>
        <a href="/comics/archive">Full Archive</a>
        <a href="/comics/series">Series List</a>
      </div>
    </div>
  </nav>
</header>

CSS for Navbars #

/* Main Navbar Styles */
.main-navbar {
  position: fixed;
  top: 0;
  width: 100%;
  padding: 1rem 0;
  background-color: #ffffff;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
  z-index: 1000; /* Added this z-index to keep it above content */
}

.main-navbar .main-toggle {
  display: none;
  border: none;
  background: transparent;
  font-size: 1.5rem;
  cursor: pointer;
}

.main-nav-links {
  display: flex;
  gap: 2rem;
}

@media (max-width: 768px) {
  .main-navbar .main-toggle {
    display: block;
  }

  .main-nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    width: 100%;
    padding: 1rem;
    background-color: #ffffff;
    flex-direction: column;
    gap: 1rem;
  }

  .main-nav-links.active {
    display: flex;
  }
}

/* Comics Navbar Styles */
.comics-navbar {
  position: sticky;
  top: 65px; /* Matches the height of the main fixed navbar */
  padding: 0.8rem 0;
  background-color: #f8f9fa;
  z-index: 999; /* Added this to layer it below the main navbar */
}

.comics-navbar .comics-toggle {
  display: none;
  border: none;
  background: transparent;
  font-size: 1.5rem;
  cursor: pointer;
}

.comics-nav-links {
  display: flex;
  gap: 1.5rem;
}

@media (max-width: 768px) {
  .comics-navbar .comics-toggle {
    display: block;
  }

  .comics-nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    width: 100%;
    padding: 1rem;
    background-color: #f8f9fa;
    flex-direction: column;
    gap: 1rem;
  }

  .comics-nav-links.active {
    display: flex;
  }
}

A quick note: The JavaScript toggle functions (to add/remove the active class) were working perfectly before I added the z-index values. I’ve verified the media queries are targeting the correct screen sizes, and all other CSS properties are unchanged from when the responsiveness worked.

内容的提问来源于stack exchange，提问作者tmoflash