nav > div.relative { 
	position: relative; 
} /* 二级菜单 */ 
nav .sub-menu { 
	display: none; 
	position: absolute; 
	top: 100%; 
	left: 0; 
	min-width: 220px; 
	background: #fff; 
	border-radius: 10px; 
	padding: 8px 0; 
	box-shadow: 0 10px 25px rgba(0,0,0,0.1); 
	z-index: 999; 
} /* 子项 */ 
nav .sub-menu a { 
	display: block; 
	padding: 10px 16px; 
	font-size: 14px; 
	color: #374151; 
	white-space: nowrap; 
} /* hover效果 */ 
nav .sub-menu a:hover { 
	background: #f5f5f5; 
	color: #0da2e7; 
}