css-渐变色矩形

效果图：

代码：
html:

css:

*{
	margin: 0;
	padding: 0;
	box-sizing: border-box;
}

.container{
	width: 100vw;
	height: 100vh;
	background-image: url('https://img0.baidu.com/it/u=3091341499,2856166635&fm=253&fmt=auto&app=138&f=PNG?w=1331&h=500');
	background-repeat: no-repeat;
	background-size: cover;
	display: flex;
	justify-content: center;
	align-items: center;
}

.bg{
	width: 500px;
	height: 45px;
	background-image:
	 linear-gradient(to top, rgba(255, 255, 255, 0), rgba(255, 255, 255, 0.05), rgba(255, 255, 255, 0)),
	 linear-gradient(to right, rgba(255, 255, 255, 0), rgba(255, 255, 255, 0.4), rgba(255, 255, 255, 0));
	 border-top: 1px solid;
	 border-bottom: 1px solid;
	 border-image: linear-gradient(to right, rgba(255, 255, 255, 0), rgba(255, 255, 255, 1), rgba(255, 255, 255, 0)) 1 1 stretch;;
}