css线性渐变兼容 background: linear-gradient(top, rgba(54, 77, 127, 0.8), rgba(54, 77, 127, 0.8)); background: -moz-linear-gradient(top, rgba(54, 77, 127, 0.8), rgba(54, 77, 127, 0.8)); /*Firefox*//*参数:top.bottom垂直,left.right水平*/ background: -ms-linear-grad