关于本节中的 background-image，可有真大神详细解释一下？
background-image: linear-gradient(45deg, #478480 25%, transparent 25%, transparent 75%, #478480 75%, #478480), linear-gradient(45deg, #478480 25%, transparent 25%, transparent 75%, #478480 75%, #478480);
渐变的参数究竟是怎么回事？
