我如何使下拉按钮工作 html css

Question

So im creating a website and I have it so when the width of the window is smaller then 768px then the navbar collapses. The navbar collapses but does not show the the individual items on navbar. The nav bar collapse is a vertical navbar. I am using Bootstrap By the way. So to sum it all up I have a vertical menue/navigation bar yet I am having trouble with getting the dropdowns to open.

here is my html: -->

<header id="home">
    <!-- Background Image -->
    <div class="bg-img" style="background-image: url('./img/background1.png');">
        <div class="overlay"></div>
    </div>
    <!-- /Background Image -->

    <!-- Nav -->
    <nav id="nav" class="navbar nav-transparent">
        <div class="container">

            <div class="navbar-header">
                <!-- Logo -->
                <div class="navbar-brand">
                    <a href="index.html">
                        <img class="logo" src="img/Logo.png" alt="logo">
                        <img class="logo-alt" src="img/Logo.png" alt="logo">
                    </a>
                </div>
                <!-- /Logo -->

                <!-- Collapse nav button -->
                <div class="nav-collapse">
                    <span></span>
                </div>
                <!-- /Collapse nav button -->
            </div>

            <!--  Main navigation  -->
            <ul class="main-nav nav navbar-nav navbar-right">

            <li><a href="#home">Home</a></li>

           <li class="has-dropdown"><a href="#AboutUs">About US</a>
                    <ul class="dropdown">
                        <li><a href="#">About Us</a></li>
                        <li><a href="#">Our Team</a></li>
                    </ul>
                </li>

            <li class="has-dropdown"><a href="#NonProfits">NonProfits</a>
                    <ul class="dropdown">
                        <li><a href="#">Requirements</a></li>
                        <li><a href="#">Services</a></li>
                        <li><a href="#">Join Our Program</a></li>
                    </ul>
                </li>
                <li class="has-dropdown"><a href="#Volunteers">Volunteers</a>
                    <ul class="dropdown">
                        <li><a href="#">Overview</a></li>
                        <li><a href="#">Sign Up</a></li>
                    </ul>
                </li>



            </ul>
            <!-- /Main navigation -->

        </div>
    </nav>
    <!-- /Nav -->

    <!-- home wrapper -->
    <div class="home-wrapper">
        <div class="container">
            <div class="row">

                <!-- home content -->
                <div class="col-md-10 col-md-offset-1">
                    <div class="home-content">

                        <h1 id="changing-word" class="white-text">We Are Creative Agency</h1>
                        <p class="white-text">Morbi mattis felis at nunc. Duis viverra diam non justo. In nisl. Nullam sit amet magna in magna gravida vehicula. Mauris tincidunt sem sed arcu. Nunc posuere.
                        </p>
                        <button class="white-btn">Get Started!</button>

                    </div>
                </div>
                <!-- /home content -->

            </div>
        </div>
    </div>
    <!-- /home wrapper -->

</header>

here is my css:

body {
    font-family: 'Varela Round', sans-serif;
    font-size: 16px;
    line-height: 1.6;
    overflow-x: hidden;
    color: #868F9B;
}

h1, h2, h3, h4, h5, h6 {
    font-family: 'Montserrat', sans-serif;
    font-weight: 700;
    margin-top: 0px;
    margin-bottom: 20px;
    color: #10161A;
}

h1 {
    font-size: 54px;
}

h2 {
    font-size: 36px;
}

h3 {
    font-size: 21px;
}

h4 {
    font-size: 18px;
}

h5 {
    font-size: 16px;
}

a {
    color: #6195FF;
    text-decoration: none;
    -webkit-transition: 0.2s opacity;
    transition: 0.2s opacity;
}

a:hover, a:focus {
    text-decoration: none;
    outline: none;
    opacity: 0.8;
    color: #6195FF;
}

.main-color {
    color: #6195FF;
}

.white-text {
    color: #FFF;
}

::-moz-selection {
    background-color: #6195FF;
    color: #FFF;
}

::selection {
    background-color: #6195FF;
    color: #FFF;
}

ul, ol {
    margin: 0;
    padding: 0;
    list-style: none
}

/* -- section  -- */

.section {
    position: relative;
}




/* --  background section  -- */

.bg-grey {
    background-color: #FAFAFA;
    border-top: 1px solid #EEE;
    border-bottom: 1px solid #EEE;
}

.bg-dark {
    background-color: #1C1D21;
}


/* --  background image section  -- */

.bg-img {
    position: absolute;
    left: 0;
    top: 0;
    right: 0;
    bottom: 0;
    z-index: -1;
    background-position: center;
    background-size: cover;
    background-attachment: fixed;
}

.bg-img .overlay {
    position: absolute;
    left: 0;
    top: 0;
    right: 0;
    bottom: 0;
    opacity: .8;
    background: #1C1D21;
}


/* --  section header  -- */

.section-header {
    position: relative;
    margin-bottom: 60px;
}

.section-header .title {
    text-transform: capitalize;
}

.title:after {
    content:"";
    display:block;
    height:4px;
    width:40px;
    background-color: #6195FF;
    margin-top: 20px;
}



/* --  Input  -- */

.main-btn, .white-btn, .outline-btn {
    display: inline-block;
    padding: 10px 35px;
    margin: 3px;
    border: 2px solid transparent;
    border-radius: 3px;
    -webkit-transition: 0.2s opacity;
    transition: 0.2s opacity;
}

.main-btn {
    background: #6195FF;
    color: #FFF;
}

.white-btn {
    background: #FFF;
    color: #10161A !important;
}

.outline-btn {
    background: transparent;
    color: #6195FF !important;
    border-color: #6195FF;
}

.main-btn:hover, .white-btn:hover, .outline-btn:hover {
    opacity: 0.8;
}
.navbar-brand {
    padding: 0;
}

.navbar-brand .logo, .navbar-brand .logo-alt {
    max-height: 50px;
    display: block;
}

#nav:not(.nav-transparent):not(.fixed-nav) .navbar-brand .logo-alt {
    display: none;
}

#nav.nav-transparent:not(.fixed-nav) .navbar-brand .logo {
    display: none;
}

#nav.fixed-nav .navbar-brand .logo-alt {
    display: none;
}

@media only screen and (max-width: 767px) {
    #nav.nav-transparent .navbar-brand .logo-alt {
        display: none !important;
    }
    #nav.nav-transparent .navbar-brand .logo {
        display: block !important;
    }
}


/*------------------------------------*\
    Navigation
\*------------------------------------*/

#nav {
    padding: 10px 0px;
    background: #FFF;
    -webkit-transition: 0.2s padding;
    transition: 0.2s padding;
    z-index: 999;
}

#nav.navbar {
    border: none;
    border-radius: 0;
    margin-bottom: 0px;
}

#nav.fixed-nav {
    position: fixed;
    left: 0;
    right: 0;
    padding: 0px 0px;
    background-color: #FFF !important;
    border-bottom: 1px solid #EEE;
}

#nav.nav-transparent {
    background: transparent;
}


/* -- default nav -- */

@media only screen and (min-width: 768px) {
    .main-nav li {
        padding: 0px 15px;
    }
    .main-nav li a {
        font-size: 19px;
        -webkit-transition: 0.2s color;
        transition: 0.2s color;
    }
    .main-nav>li>a {
        color: #10161A;
        padding: 15px 0px;
    }
    #nav.nav-transparent:not(.fixed-nav) .main-nav>li>a {
        color: #fff;
    }
    .main-nav>li>a:hover, .main-nav>li>a:focus, .main-nav>li.active>a {
        background: transparent;
        color: red;
    }
    .main-nav>li>a:after {
        content: "";
        display: block;
        background-color: red;
        height: 2px;
        width: 0%;
        -webkit-transition: 0.2s width;
        transition: 0.2s width;
    }
    .main-nav>li>a:hover:after, .main-nav>li.active>a:after {
        width: 100%;
    }
    /* dropdown */
    .has-dropdown {
        position: relative;
    }
    .has-dropdown>a:before {
        font-family: 'FontAwesome';
        content: "\f054";
        font-size: 6px;
        margin-left: 6px;
        float: right;
        -webkit-transform: rotate(90deg);
        -ms-transform: rotate(90deg);
        transform: rotate(90deg);
        -webkit-transition: 0.2s transform;
        transition: 0.2s transform;
    }
    .dropdown {
        position: absolute;
        right: -50%;
        top: 0;
        background-color: red;
        width: 200px;
        -webkit-box-shadow: 0px 5px 5px -5px rgba(53, 64, 82, 0.2);
        box-shadow: 0px 5px 5px -5px rgba(53, 64, 82, 0.2);
        -webkit-transform: translateY(15px) translateX(50%);
        -ms-transform: translateY(15px) translateX(50%);
        transform: translateY(15px) translateX(50%);
        opacity: 0;
        visibility: hidden;
        -webkit-transition: 0.2s all;
        transition: 0.2s all;
    }
    .main-nav>.has-dropdown>.dropdown {
        top: 100%;
        right: 50%;
    }
    .main-nav>.has-dropdown>.dropdown .dropdown.dropdown-left {
        right: 150%;
    }
    .dropdown li a {
        display: block;
        color: #FFF;
        border-top: 1px solid rgba(250, 250, 250, 0.1);
        padding: 10px 0px;
    }
    .dropdown li:nth-child(1) a {
        border-top: none;
    }
    .has-dropdown:hover>.dropdown {
        opacity: 1;
        visibility: visible;
        -webkit-transform: translateY(0px) translateX(50%);
        -ms-transform: translateY(0px) translateX(50%);
        transform: translateY(0px) translateX(50%);
    }
    .has-dropdown:hover>a:before {
        -webkit-transform: rotate(0deg);
        -ms-transform: rotate(0deg);
        transform: rotate(0deg);
    }
    .nav-collapse {
        display: none;
    }
}


/* -- mobile nav -- */

@media only screen and (max-width: 767px) {
    #nav {
        padding: 0px 0px;
    }
    #nav.nav-transparent {
        background: #FFF;
    }
    .main-nav {
        position: fixed;
        right: 0;
        height: calc(100vh - 80px);
        -webkit-box-shadow: 0px 80px 0px 0px #1C1D21;
        box-shadow: 0px 80px 0px 0px #1C1D21;
        max-width: 250px;
        width: 0%;
        -webkit-transform: translateX(100%);
        -ms-transform: translateX(100%);
        transform: translateX(100%);
        margin: 0;
        overflow-y: auto;
        background: #1C1D21;
        -webkit-transition: 0.2s all;
        transition: 0.2s all;
    }
    #nav.open .main-nav {
        -webkit-transform: translateX(0%);
        -ms-transform: translateX(0%);
        transform: translateX(0%);
        width: 100%;
    }
    .main-nav li {
        border-top: 1px solid rgba(250, 250, 250, 0.1);
    }
    .main-nav li a {
        display: block;
        color: #FFF;
        -webkit-transition: 0.2s all;
        transition: 0.2s all;
    }
    .main-nav>li.active {
        border-left: 6px solid red;
    }
    .main-nav li a:hover, .main-nav li a:focus {
        background-color: red;
        color: #FFF;
        opacity: 1;
    }
    .has-dropdown>a:after {
        content: "\f054";
        font-family: 'FontAwesome';
        float: right;
        -webkit-transition: 0.2s -webkit-transform;
        transition: 0.2s -webkit-transform;
        transition: 0.2s transform;
        transition: 0.2s transform, 0.2s -webkit-transform;
    }
    .dropdown {
        opacity: 0;
        visibility: hidden;
        height: 0;
        background: rgba(250, 250, 250, 0.1);
    }
    .dropdown li a {
        padding: 6px 10px;
    }
    .has-dropdown.open-drop>a:after {
        -webkit-transform: rotate(90deg);
        -ms-transform: rotate(90deg);
        transform: rotate(90deg);
    }
    .has-dropdown.open-drop>.dropdown {
        opacity: 1;
        visibility: visible;
        height: auto;
        -webkit-transition: 0.2s all;
        transition: 0.2s all;
    }
}


/* -- nav btn collapse -- */

.nav-collapse {
    position: relative;
    float: right;
    width: 40px;
    height: 40px;
    margin-top: 5px;
    margin-right: 5px;
    cursor: pointer;
    z-index: 99999;
}

.nav-collapse span {
    display: block;
    -webkit-transform: translate(-50%, -50%);
    -ms-transform: translate(-50%, -50%);
    transform: translate(-50%, -50%);
    position: absolute;
    top: 50%;
    left: 50%;
    width: 25px;
}

.nav-collapse span:before, .nav-collapse span:after {
    content: "";
    display: block;
}

.nav-collapse span, .nav-collapse span:before, .nav-collapse span:after {
    height: 4px;
    background: #10161A;
    -webkit-transition: 0.2s all;
    transition: 0.2s all;
}

.nav-collapse span:before {
    -webkit-transform: translate(0%, 10px);
    -ms-transform: translate(0%, 10px);
    transform: translate(0%, 10px);
}

.nav-collapse span:after {
    -webkit-transform: translate(0%, -14px);
    -ms-transform: translate(0%, -14px);
    transform: translate(0%, -14px);
}

#nav.open .nav-collapse span {
    background: transparent;
}

#nav.open .nav-collapse span:before {
    -webkit-transform: translateY(0px) rotate(-135deg);
    -ms-transform: translateY(0px) rotate(-135deg);
    transform: translateY(0px) rotate(-135deg);
}

#nav.open .nav-collapse span:after {
    -webkit-transform: translateY(-4px) rotate(135deg);
    -ms-transform: translateY(-4px) rotate(135deg);
    transform: translateY(-4px) rotate(135deg);
}


/*------------------------------------*\
    Header
\*------------------------------------*/

header {
    position: relative;
}

#home {
    height: 100vh;
}

#home .home-wrapper {
    position: absolute;
    left: 0px;
    right: 0px;
    top: 50%;
    -webkit-transform: translateY(-50%);
    -ms-transform: translateY(-50%);
    transform: translateY(-50%);
    text-align: center;
}

.home-content h1 {
  text-transform: uppercase;
}
.home-content button {
  margin-top: 20px;
}

.header-wrapper h2 {
    display: inline-block;
    margin-bottom: 0px;
}

.header-wrapper .breadcrumb {
    float: right;
    background: transparent;
    margin-bottom: 0px;
}

.header-wrapper .breadcrumb .breadcrumb-item.active {
    color: #868F9B;
}

.breadcrumb>li+li:before {
    color: #868F9B;
}

Answer 1

This topic is tagged with "Bootstrap 4", but you are not using the correct syntax for this framework version.

Now, that's a Bootstrap 4 navbar with dropdown:

 <!doctype html> <html lang="en"> <head> <!-- Required meta tags --> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no"> <!-- Bootstrap CSS --> <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous"> <title>Hello, world!</title> </head> <body> <nav class="navbar navbar-expand-lg navbar-light bg-light"> <a class="navbar-brand" href="#">Navbar</a> <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation"> <span class="navbar-toggler-icon"></span> </button> <div class="collapse navbar-collapse" id="navbarSupportedContent"> <ul class="navbar-nav mr-auto"> <li class="nav-item active"> <a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a> </li> <li class="nav-item"> <a class="nav-link" href="#">Link</a> </li> <li class="nav-item dropdown"> <a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false"> Dropdown </a> <div class="dropdown-menu" aria-labelledby="navbarDropdown"> <a class="dropdown-item" href="#">Action</a> <a class="dropdown-item" href="#">Another action</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="#">Something else here</a> </div> </li> <li class="nav-item"> <a class="nav-link disabled" href="#">Disabled</a> </li> </ul> <form class="form-inline my-2 my-lg-0"> <input class="form-control mr-sm-2" type="search" placeholder="Search" aria-label="Search"> <button class="btn btn-outline-success my-2 my-sm-0" type="submit">Search</button> </form> </div> </nav> <!-- Optional JavaScript --> <!-- jQuery first, then Popper.js, then Bootstrap JS --> <script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script> <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js" integrity="sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q" crossorigin="anonymous"></script> <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js" integrity="sha384-JZR6Spejh4U02d8jOt6vLEHfe/JQGiRRSQQxSfFWpi1MquVdAyjUar5+76PVCmYl" crossorigin="anonymous"></script> </body> </html>

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