css下拉Dropdown菜单

源码

<div class="container">
	<div class="drop drop--down"><button class="btn">Dropdown</button>
		<div class="drop__content">
			<div class="drop-arrow"></div>
			<div class="drop-list -size-large -position-right -border-rounded">
				<button class="drop-list__btn">Bootstrapmb.Com</button>
				<button class="drop-list__btn">jqueryScript.Com</button>
				<button class="drop-list__btn">Google.Com</button>
			</div>
		</div>
	</div>
	<div class="drop drop--up"><button class="btn">Dropup</button>
		<div class="drop__content">
			<div class="drop-arrow"></div>
			<div class="drop-list -size-medium -position-right">
				<button class="drop-list__btn">Action 1</button>
				<button class="drop-list__btn">Action 2</button>
			</div>
		</div>
	</div>
	<div class="drop drop--down -color-lighter"><button class="btn">Light Theme</button>
		<div class="drop__content">
			<div class="drop-arrow"></div>
			<div class="drop-list -size-medium -position-right">
				<button class="drop-list__btn">Action 1</button>
				<button class="drop-list__btn">Action 2</button>
			</div>
		</div>
	</div>
</div>
<style>
.container {
    margin: 150px auto;
    max-width: 960px;
	text-align: center;
}	
.btn{
    padding: 1.25rem;
    border: 0;
    border-radius: 3px;
    background-color: #4F46E5;
    color: #fff;
    cursor: pointer;	
}	
.drop {
    cursor: pointer;
    display: inline-block;
    min-width: 14px;
    overflow: visible;
    position: relative;
    text-align: center;
    text-rendering: optimizeLegibility;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    font-smoothing: antialiased
}

.drop.is-disabled {
    cursor: not-allowed
}

.drop__content {
    position: absolute;
    visibility: hidden;
    width: 100%
}

.drop--down .drop__content {
    top: 100%
}

.drop--up .drop__content {
    bottom: 100%
}

.drop:not(.is-disabled).is-open .drop__content,.drop:not(.is-disabled):hover .drop__content {
    visibility: visible
}

.drop__content.-transition-fade-in {
    opacity: 0;
    transition: visibility 0s linear,opacity .25s ease-in;
    transition-delay: .1s
}

.drop.is-open .drop__content.-transition-fade-in,.drop:hover .drop__content.-transition-fade-in {
    opacity: 1;
    transition-delay: 0s
}

.drop__content.-transition-slide-in {
    opacity: 0;
    transition: visibility 0s linear,opacity .25s ease,transform .25s ease;
    transition-delay: .1s
}

.drop--up .drop__content.-transition-slide-in {
    transform: translateY(-10px)
}

.drop--down .drop__content.-transition-slide-in {
    transform: translateY(10px)
}

.drop.is-open .drop__content.-transition-slide-in,.drop:hover .drop__content.-transition-slide-in {
    opacity: 1;
    transform: translateY(0);
    transition-delay: 0s
}

.drop-arrow {
    border-left: 7px solid transparent;
    border-right: 7px solid transparent;
    height: 0;
    margin: 0 auto;
    width: 0
}

.drop--up .drop-arrow {
    border-top: 7px solid #373737;
    margin-bottom: 2px
}

.drop--down .drop-arrow {
    border-bottom: 7px solid #373737;
    margin-top: 2px
}

.drop--up.-color-secondary .drop-arrow {
    border-top-color: #148a73
}

.drop--down.-color-secondary .drop-arrow {
    border-bottom-color: #148a73
}

.drop--up.-color-lighter .drop-arrow {
    border-top-color: #bdc3c7
}

.drop--down.-color-lighter .drop-arrow {
    border-bottom-color: #bdc3c7
}

.drop-list {
    min-width: 100%;
    background-color: #373737;
    font-size: .8em;
    font-weight: 400;
    list-style: none;
    margin: 0;
    padding: 5px;
    position: absolute;
    white-space: nowrap
}

.drop.-color-secondary .drop-list {
    background-color: #148a73
}

.drop.-color-lighter .drop-list {
    background-color: #bdc3c7
}

.drop--down .drop-list {
    top: 100%
}

.drop--up .drop-list {
    bottom: 100%
}

.drop-list.-position-left.-pull-left {
    margin-right: 10.5px
}

.drop-list.-position-left.-pull-right {
    margin-right: -10.5px
}

.drop-list.-position-center.-pull-left {
    margin-left: -10.5px
}

.drop-list.-position-center.-pull-right {
    margin-left: 10.5px
}

.drop-list.-position-right.-pull-left {
    margin-left: -10.5px
}

.drop-list.-position-right.-pull-right {
    margin-left: 10.5px
}

.drop-list.-position-center {
    left: 50%;
    transform: translateX(-50%)
}

.drop-list.-position-left {
    right: 0
}

.drop-list.-position-right {
    left: 0
}

.drop-list.-size-medium {
    width: 150px
}

.drop-list.-size-large {
    width: 225px
}

.drop-list.-border-rounded {
    border-radius: 5px
}

.drop--down .drop-list::before,.drop--up .drop-list::after {
    content: " ";
    height: 19px;
    left: 0;
    position: absolute;
    width: 100%
}

.drop--down .drop-list::before {
    bottom: 100%
}

.drop--up .drop-list::after {
    top: 100%
}

.drop-list__item {
    display: block
}

.drop-list__btn {
    background-color: transparent;
    border: 0;
    border-radius: 2px;
    color: #FFF;
    cursor: pointer;
    font: inherit;
    display: block;
    outline: 0;
    padding: 11.2px;
    text-align: left;
    text-decoration: none;
    width: 100%
}

.drop-list__btn.is-selected {
    background-color: #565656
}

.drop.-color-secondary .drop-list__btn.is-selected {
    background-color: #1cbfa0
}

.drop.-color-lighter .drop-list__btn.is-selected {
    background-color: #a7afb4
}

.drop-list__btn:hover {
    background-color: #515151
}

.drop.-color-secondary .drop-list__btn:hover {
    background-color: #1ab798
}

.drop.-color-lighter .drop-list__btn:hover {
    background-color: #a1aab0
}

</style>

链接: https://fly63.com/course/33_1602