我将此 css 应用于我的 DIV
div#envelope{
width: 400px;
margin: 140px 23% 10px 16%;
padding:33px 0 10px 0;
border-radius:2px;
background-color: rgba(255,255,255,0.5);
background-image: -webkit-gradient(
linear,
right bottom,
left top,
color-stop(0, rgba(255, 255, 255, 0.5)),
color-stop(0.50, rgba(255, 255, 255, 0.5))
);
background-image: -o-linear-gradient(left top, rgba(255, 255, 255, 1) 0%, rgba(255, 255, 255, 0.5) 50%);
background-image: -moz-linear-gradient(left top, rgba(255, 255, 255, 1) 0%, rgba(255, 255, 255, 0.5) 50%);
background-image: -webkit-linear-gradient(left top, rgba(255, 255, 255, 1) 0%, rgba(255, 255, 255, 0.5) 50%);
background-image: -ms-linear-gradient(left top, rgba(255, …