.nav {
    width:100%;
    background-image: linear-gradient(var(--theme1),var(--theme2));
}

.nav_box{
	float:left;
	width:100%;
	max-width: 864px;
}

.nav_content,.nav_content_hidden{
	display:inline-block;
	width:10%;
	text-align:center;
    cursor:pointer;
}

.nav_content:hover,.nav_content_hidden:hover{
	background-color:rgba(255,255,255,0.2); 
}

.nav_dropdown{
	background-image:linear-gradient(135deg,var(--theme1),var(--theme2));
	list-style: none;
	text-align: left;
	overflow: hidden;
	border-radius: 8px;
}

.nav_dropdown li{
	font-size: 1.25em;
	background-color: rgba(255,255,255,0.2);
}

.nav_dropdown li:hover{
	background-color: rgba(255,255,255,1);
	color:var(--theme1);
}

/*搜索框*/
#search_box {
	float: right;
	display:inline-block;
	border-radius: 10px;
	border-style:inset;
	border-width: 2px;
	border-color: var(--theme2);
	background-color: #FFFFFF;
	margin-top: 10px;
	padding: 6px;
}

#search_content {
	float:left;
	display: inline-block;
	outline: none;
	border:none;
	border-right-style:solid;
	border-width: 2px;
	border-color:var(--theme2);
	font-size: 1.8em;
	font-family: searchbox;
	width:180px;
}

#search_icon {
	float:left;
	display: inline-block;
	padding-left: 6px;
}

#search_icon_image{
	opacity: 0.6;
	cursor:pointer;
}

#search_icon_image:hover{
	opacity: 0.3;
}

.extra_term{
	position:relative;
	display:inline-block;
	cursor:pointer;
	width:30%;
}

.extra_subterm{
	position:relative;
	display:inline-block;
	cursor:pointer;
	width:25%;
}

.extra_wings{
	width:80%;
}

.extra_term_content{
	position: absolute;
	top:45%;
	width:100%;
	text-shadow: 1px 1px 0px #000000;
}

@media screen and (max-width: 1200px) {
	#search_box{
		display: none;
	}
}

@media screen and (max-width: 800px) {
	.nav_content{
		width:16.6%;
	}
	.nav_content_hidden{
		display:none;
	}
}