多階層ドロップダウン

デモ

See the Pen nav 16 by logsuke (@design-list) on CodePen.

コード

<!-- Boxicons headタグ内へ -->
<link href='https://unpkg.com/boxicons@2.1.2/css/boxicons.min.css' rel='stylesheet'>

    <header class="header" id="header">
        <nav class="nav">
            <a href="#" class="logo">
                <svg viewBox="0 0 496 512" width="100" title="meh-rolling-eyes">
                    <path
                        d="M248 8C111 8 0 119 0 256s111 248 248 248 248-111 248-248S385 8 248 8zM88 224c0-24.3 13.7-45.2 33.6-56-.7 2.6-1.6 5.2-1.6 8 0 17.7 14.3 32 32 32s32-14.3 32-32c0-2.8-.9-5.4-1.6-8 19.9 10.8 33.6 31.7 33.6 56 0 35.3-28.7 64-64 64s-64-28.7-64-64zm224 176H184c-21.2 0-21.2-32 0-32h128c21.2 0 21.2 32 0 32zm32-112c-35.3 0-64-28.7-64-64 0-24.3 13.7-45.2 33.6-56-.7 2.6-1.6 5.2-1.6 8 0 17.7 14.3 32 32 32s32-14.3 32-32c0-2.8-.9-5.4-1.6-8 19.9 10.8 33.6 31.7 33.6 56 0 35.3-28.7 64-64 64z" />
                </svg>
                logo
            </a>
            <div class="nav-menu" id="navMenu">
                <ul class="nav-links">
                    <li class="nav-item">
                        <a href="#section1" class="nav-link">Section1</a>
                        <ul class="drop-down">
                            <li class="nav-item"><a href="#section1-1">Section1-1</a></li>
                            <li class="nav-item"><a href="#section1-2">Section1-2</a></li>
                            <li class="nav-item">
                                <a href="#section1-3">Section1-3</a>
                                <ul class="child-drop-down">
                                    <li class="nav-item"><a href="#section1-3-1">Section1-3-1</a></li>
                                    <li class="nav-item"><a href="#section1-3-2">Section1-3-2</a></li>
                                    <li class="nav-item"><a href="#section1-3-3">Section1-3-3</a></li>
                                </ul>
                            </li>
                            <li class="nav-item"><a href="#section1-4">Section1-4</a></li>
                        </ul>
                    </li>
                    <li class="nav-item"><a href="#section2" class="nav-link">Section2</a></li>
                    <li class="nav-item"><a href="#section3" class="nav-link">Section3</a></li>
                    <li class="nav-item">
                        <a href="#section4" class="nav-link">Section4</a>
                    </li>
                </ul>
            </div>

        </nav>
    </header>

/*=== Base ===*/

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: sans-serif;
}

:root {
  --nav-height: 8rem;
  --max-width: 1024px;
  --container-padding: 0 4rem;
  --gap: 2rem;
  --bg-color: rgb(240, 240, 240);
}

/*=== Font ratio ===*/

html {
  scroll-behavior: smooth;
  font-size: 62.5%;
}

body {
  font-size: 1.6rem;
}

ul {
  list-style: none;
}

a {
  text-decoration: none;
}

/* header */
header {
  width: 100%;
  position: fixed;
  top: 0;
  left: 0;
  z-index: 100;
  background-color: var(--bg-color);
}

.nav svg {
  width: 25px;
  padding: 2px;
  margin-right: 5px;
}

/* nav */
.nav {
  width: 100%;
  max-width: var(--max-width);
  height: var(--nav-height);
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin: 0 auto;
  padding: 0 3rem;
}

.logo,
.nav-toggle {
  color: var(--text-color);
  cursor: pointer;
}

.logo {
  font-weight: bold;
  font-size: 2rem;
  z-index: 100;
  display: flex;
  justify-content: center;
  align-items: center;
}

.nav-menu {
    margin: 0 auto;

}

.nav-links {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 2rem;
}

.nav-links .nav-item {
  position: relative;
}

.nav-links a {
  color: var(--text-color);
  display: flex;
  justify-content: center;
  align-items: center;
  height: var(--nav-height);
}

.nav-links a:hover {
  color: rgb(134, 170, 207);
}

.nav-links>a {
  color: var(--text-color);
  display: flex;
  justify-content: center;
  align-items: center;
  height: var(--nav-height);
  border: none;
  font-size: 1.6rem;
  cursor: pointer;
}

.drop-down {
  position: absolute;
  top: var(--nav-height);
  left: 50%;
  transform: translateX(-50%);
  background: var(--bg-color);
  opacity: 0;
  pointer-events: none;
}

.drop-down a {
  width: 150px;
  height: 50px;
}

.drop-down>li, .child-drop-down>li {
  border-bottom: 1px solid rgb(88, 87, 87);
}

.drop-down>li:last-child, .child-drop-down>li:last-child {
  border: none;
}

.child-drop-down {
  position: absolute;
  top: 0;
  right: -100%;
  background: var(--bg-color);
  opacity: 0;
  pointer-events: none;
}

.nav-item:hover>.drop-down, .nav-item:hover>.child-drop-down {
  opacity: 1;
  pointer-events: auto;
}