50天50个前端页面练习Day3：旋转导航栏今天来实现一个旋转导航栏的功能，页面显示文章，点击菜单按钮，旋转出导航栏。

今天来实现一个旋转导航栏的功能，页面显示文章，点击菜单按钮，旋转出导航栏。效果如下：

tt0.top-217446.gif 首先，实现思路是先用HTML把所有元素先画好。

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.14.0/css/all.min.css" integrity="sha512-1PKOgIY59xJ8Co8+NE6FZ+LOAZKjy+KY8iq0G4B3CyeY6wYHN3yt9PW0XpSriVlkMXe40PTKnXrLnZ9+fkDaog==" crossorigin="anonymous" />
    <link rel="stylesheet" href="style.css" />
    <title>旋转导航栏</title>
</head>
<body>
    <div class="container">
        <div class="circle-container">
            <div class="circle">
                <button id="close">
                    <i class="fas fa-times"></i>
                </button>
                <button id="open">
                    <i class="fas fa-bars"></i>
                </button>
            </div>
        </div>

        <div class="content">
            <h1>Amazing Article</h1>
            <small>Florin Pop</small>
            <p>Lorem ipsum dolor sit amet consectetur adipisicing elit. Accusantium quia in ratione dolores cupiditate, maxime aliquid impedit dolorem nam dolor omnis atque fuga labore modi veritatis porro laborum minus, illo, maiores recusandae cumque ipsa quos. Tenetur, consequuntur mollitia labore pariatur sunt quia harum aut. Eum maxime dolorem provident natus veritatis molestiae cumque quod voluptates ab non, tempore cupiditate? Voluptatem, molestias culpa. Corrupti, laudantium iure aliquam rerum sint nam quas dolor dignissimos in error placeat quae temporibus minus optio eum soluta cupiditate! Cupiditate saepe voluptates laudantium. Ducimus consequuntur perferendis consequatur nobis exercitationem molestias fugiat commodi omnis. Asperiores quia tenetur nemo ipsa.</p>

            <h3>My Dog</h3>
            <img src="https://images.unsplash.com/photo-1507146426996-ef05306b995a?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=2100&q=80" alt="doggy" />
            <p>Lorem, ipsum dolor sit amet consectetur adipisicing elit. Sit libero deleniti rerum quo, incidunt vel consequatur culpa ullam. Magnam facere earum unde harum. Ea culpa veritatis magnam at aliquid. Perferendis totam placeat molestias illo laudantium? Minus id minima doloribus dolorum fugit deserunt qui vero voluptas, ut quia cum amet temporibus veniam ad ea ab perspiciatis, enim accusamus asperiores explicabo provident. Voluptates sint, neque fuga cum illum, tempore autem maxime similique laborum odio, magnam esse. Aperiam?</p>
        </div>
    </div>

    <nav>
        <ul>
            <li><i class="fas fa-home"></i><a href="#"> Home</a></li>
            <li><i class="fas fa-user-alt"></i><a href="#"> About</a></li>
            <li><i class="fas fa-envelope"></i><a href="#"> Contact</a></li>
        </ul>
    </nav>
    <script src="script.js"></script>
</body>
</html>

其次是CSS部分，左上角的两个按钮，一个按钮正常，另外一个按钮初识就应该旋转出视窗。菜单栏也是，每个旋转出视窗并且角度不同。通过JS增/删属性来实现样式的变换。代码如下

@import url('https://fonts.googleapis.com/css?family=Lato&display=swap');

* {
    box-sizing: border-box;
}
body {
    font-family: 'Lato', sans-serif;
    background-color: #333;
    color: #222;
    overflow-x: hidden;
    margin: 0;
}
.container {
    background-color: #fafafa;
    transform-origin: top left;
    transition: transform 0.5s linear;
    width: 100vw;
    min-height: 100vh;
    padding: 50px;
}
.container.show-nav {
    transform: rotate(-20deg);
}

.circle-container {
    position: fixed;
    top: -100px;
    left: -100px;
}
.circle {
    background-color: #ff7979;
    height: 200px;
    width: 200px;
    border-radius: 50%;
    position: relative;
    transition: transform 0.5s linear;
}
.container.show-nav .circle {
    transform: rotate(-70deg);
}
.circle button {
    cursor: pointer;
    position: absolute;
    top: 50%;
    left: 50%;
    height: 100px;
    background: transparent;
    border: 0;
    font-size: 26px;
    color: #fff;
}
.circle button:focus {
    outline: none;
}

.circle button#open {
    left: 60%;
}

.circle button#close {
    top: 60%;
    transform: rotate(90deg);
    transform-origin: top left;
}
.container.show-nav + nav li {
    transform: translateX(0);
    transition-delay: 0.3s;
}

nav {
    position: fixed;
    bottom: 40px;
    left: 0;
    z-index: 100;
}

nav ul {
    list-style-type: none;
    padding-left: 30px;
}

nav ul li {
    text-transform: uppercase;
    color: #fff;
    margin: 40px 0;
    transform: translateX(-100%);
    transition: transform 0.4s ease-in;
}

nav ul li i {
    font-size: 20px;
    margin-right: 10px;
}

nav ul li + li {
    margin-left: 15px;
    transform: translateX(-150%);
}

nav ul li + li + li {
    margin-left: 30px;
    transform: translateX(-200%);
}

nav a{
    color: #fafafa;
    text-decoration: none;
    transition: all 0.5s;
}

nav a:hover {
    color: #FF7979;
    font-weight: bold;
}

.content img {
    max-width: 100%;
}

.content {
    max-width: 1000px;
    margin: 50px auto;
}

.content h1 {
    margin: 0;
}

.content small {
    color: #555;
    font-style: italic;
}

.content p {
    color: #333;
    line-height: 1.5;
}

const open = document.getElementById('open')
const close = document.getElementById('close')
const container = document.querySelector('.container')

open.addEventListener('click', () => container.classList.add('show-nav'))

close.addEventListener('click', () => container.classList.remove('show-nav'))