Jam*_*mna 4 css media xhtml w3c-validation media-queries
我尝试使用@media查询根据不同的屏幕大小修复包装div的宽度
我写了这些代码行
@media screen and (min-width:768px) and (max-width:1023px) {
 #wrapper {
 width:625px;
 padding-left: 50px;
 margin:0 auto;
}
}
 @media screen and (min-width:1024px) and (max-width:2047px) {
 #wrapper {
 width:865px;
 margin:0 auto;
 padding-left: 50px;
 width: 927px;
}
}
当我在W3C CSS验证服务中检查我的文件时,我得到了这些错误
Value Error : min-width Property min-width doesn't exist for media screen : 768px 768px
Value Error : max-width Property max-width doesn't exist for media screen : 1023px 1023px
Value Error : min-width Property min-width doesn't exist for media screen : 1024px 1024px
Value Error : max-width Property max-width doesn't exist for media screen : 2047px 2047px 
这类错误背后的原因是什么?