How to Make CSS Responsive Navbar with Dropdown?

In this post, I will share with you a project of a responsive navigation bar with dropdown menu.

Here is the live demo of the navigation bar –

<header class="header">
    <div class="header-wrap flex">
        <section class="logo"><a href="">DevBabu.Com</a></section>
        <section class="navbar">
            <button class="close-navbar">
                <svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="feather feather-x"><line x1="18" y1="6" x2="6" y2="18"></line><line x1="6" y1="6" x2="18" y2="18"></line></svg>
            </button>
            <nav>
                <ul class="flex">
                    <li><a href="">Home</a></li>
                    <li><a href="">About</a></li>
                    <li><a href="">Menu</a>
                        <ul>
                            <li><a href="">Item 1 is red</a></li>
                            <li><a href="">Item 2 is blue</a></li>
                            <li><a href="">Item 3 is green</a></li>
                            <li><a href="">Item 4 is yellow</a></li>
                        </ul>
                    </li>
                    <li><a href="">Contact</a></li>
                </ul>
            </nav>
        </section>
        <section class="open-navbar">
            <button>
                <svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="feather feather-menu"><line x1="3" y1="12" x2="21" y2="12"></line><line x1="3" y1="6" x2="21" y2="6"></line><line x1="3" y1="18" x2="21" y2="18"></line></svg>
            </button>
        </section>
    </div>        
</header>

@charset "UTF-8";
@import url("https://fonts.googleapis.com/css2?family=Lobster&family=Open+Sans:wght@400;700&display=swap");
*,
*::before,
*::after {
    box-sizing: border-box;
    line-height: 1.5em;
}

html {
    font-size: 16px;
    -webkit-text-size-adjust: 100%;
}

body {
    margin: 0;
    overflow-wrap: break-word;
    font-family: "Open Sans", sans-serif;
    background-color: #f7f7f7;
    -moz-osx-font-smoothing: grayscale;
    -webkit-font-smoothing: antialiased;
}

.flex {
    display: flex;
    flex-wrap: wrap;
}

.header {
    background-color: #19191c;
    z-index: 1;
}
.header a {
    color: #cccccc;
    text-decoration: none;
}

.header-wrap {
    max-width: 900px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    flex-wrap: wrap;
    align-items: center;
}
.header-wrap ul {
    padding: 0;
    margin: 0;
    align-items: stretch;
    z-index: 9;
}
.header-wrap ul a {
    text-transform: uppercase;
    font-weight: bold;
}
.header-wrap ul ul {
    display: block;
}
.header-wrap ul ul a {
    text-transform: capitalize;
}
.header-wrap .logo {
    flex-grow: 1;
    font-size: 28px;
    font-family: "Lobster", cursive;
}
.header-wrap .logo a {
    color: #f9f9f9;
}

.navbar {
    background-color: #19191c;
    position: fixed;
    top: 0;
    right: -120%;
    width: 70%;
    height: 100%;
    z-index: 999;
    padding: 30px;
    opacity: 0;
    transition: right 0.3s, opacity 0.4s;
}
.navbar ul {
    flex-direction: column;
    gap: 20px;
    list-style-type: none;
    font-size: 22px;
}
.navbar ul a:hover {
    color: #f9f9f9;
}
.navbar ul ul {
    margin-left: 1.25rem;
    font-weight: normal;
}
.navbar ul ul a {
    font-weight: normal;
    font-size: 0.8em;
}
.navbar ul ul li::before {
    content: "⁍";
    margin-right: 5px;
    color: #cccccc;
}

.open-navbar button,
.close-navbar {
    all: unset;
    color: #cccccc;
    cursor: pointer;
    padding: 20px 10px;
    display: flex;
}
.open-navbar button:hover,
.close-navbar:hover {
    color: #f9f9f9;
}

.close-navbar {
    position: absolute;
    top: -10px;
    right: 0%;
}

.show-navbar {
    right: 0;
    opacity: 1;
}
.show-navbar ul ul {
    height: 0;
    overflow: hidden;
}
.show-navbar ul ul a {
    text-decoration: none;
}
.show-navbar ul ul.show-submenu {
    height: auto;
}
.show-navbar ul .submenu-btn::after {
    content: "⭥";
    margin-left: 5px;
}

@media (width >= 720px) {
    .header-wrap ul a {
        padding-left: 20px;
        padding-right: 20px;
    }
}
@media (width >= 620px) {
    .navbar {
        display: block;
        position: relative;
        padding: 0;
        inset: 0 !important;
        width: auto;
        height: auto;
        opacity: 1 !important;
    }
    .navbar ul {
        flex-direction: row;
        font-size: 1rem;
    }
    .navbar ul a {
        display: block;
        padding: 30px 15px;
    }
    .navbar ul a:hover {
        text-decoration: underline;
        background-color: rgba(0, 0, 0, 0.9);
    }
    .navbar ul li ul {
        background-color: #19191c;
        position: absolute;
        opacity: 0;
        visibility: hidden;
        translate: 0 24px;
        transition: 0.3s;
        margin: 0;
    }
    .navbar ul li ul a {
        padding: 9px 12px;
        font-size: 14px;
        text-decoration: none !important;
    }
    .navbar ul ul li::before {
        all: unset;
    }
    .navbar ul li:hover ul {
        visibility: visible;
        translate: 0 0;
        opacity: 1;
    }
    .navbar ul li:hover a {
        color: #f9f9f9;
        text-decoration: underline;
    }
    .close-navbar,
    .open-navbar {
        display: none;
    }
}

This javascript code is for mobile devices only –

const navbar = document.querySelector('.navbar');
const openNav = document.querySelector('.open-navbar button');
const closeNav = document.querySelector('.close-navbar');
const innerUl = document.querySelectorAll('.navbar ul ul');

function submenuTrigger(e, el){
    e.preventDefault();
    el.classList.toggle('show-submenu');
}

innerUl.forEach((el) => {
    if(el.previousElementSibling.nodeName === 'A'){
        el.previousElementSibling.onclick = (e) => submenuTrigger(e, el);
    }
    el.previousElementSibling.classList.add("submenu-btn");
});

openNav.onclick = () => navbar.classList.add('show-navbar');
closeNav.onclick = () => navbar.classList.remove('show-navbar');