CSS 使用媒体查询定位不同的屏幕尺寸
示例
通常，响应式Web设计涉及媒体查询，它们是CSS块，仅在满足条件时才执行。这对于响应式Web设计很有用，因为您可以使用媒体查询为网站的移动版本和桌面版本指定不同的CSS样式。
@media only screen and (min-width: 300px) and (max-width: 767px) {
.site-title {
font-size: 80%;
}
/* Styles in this block are only applied if the screen size is atleast 300px wide, but no more than 767px */
}
@media only screen and (min-width: 768px) and (max-width: 1023px) {
.site-title {
font-size: 90%;
}
/* Styles in this block are only applied if the screen size is atleast 768px wide, but no more than 1023px */
}
@media only screen and (min-width: 1024px) {
.site-title {
font-size: 120%;
}
/* Styles in this block are only applied if the screen size is over 1024px wide. */
}