我一直在做一些关于媒体查询的研究，但我仍然不太明白如何针对特定尺寸的设备。
我希望能够瞄准台式机、平板电脑和手机。我知道会有一些差异，但如果有一个通用的系统可以用来针对这些设备就好了。
我找到了一些例子:
# Mobile
only screen and (min-width: 480px)
# Tablet
only screen and (min-width: 768px)
# Desktop
only screen and (min-width: 992px)
# Huge
only screen and (min-width: 1280px)
Or:
# Phone
only screen and (max-width:320px)
# Tablet
only screen and (min-width:321px) and (max-width:768px)
# Desktop
only screen and (min-width:769px)
每个设备的断点应该是什么?
当前回答
这不是像素数的问题，而是屏幕上字符的实际大小(以毫米或英寸为单位)的问题，这取决于像素密度。 因此，“min-width:”和“max-width:”是无用的。 关于这个问题的完整解释如下: 设备像素比到底是什么?
“@media”查询会考虑像素数和设备像素比，从而产生“虚拟分辨率”，这是你在设计页面时必须考虑的问题:如果你的字体固定宽度为10px，“虚拟水平分辨率”为300 px，那么一行就需要30个字符。
其他回答
如果你想瞄准一个设备，那么只需要写min-device-width。例如:
为iPhone
@media only screen and (min-device-width: 480px){}
为平板电脑
@media only screen and (min-device-width: 768px){}
这里有一些不错的文章:
如何使你的网站适合苹果iPad CSS3媒体查询
因为有许多不同的屏幕尺寸总是在变化，最有可能总是在变化，最好的方法是根据你的设计来设置断点和媒体查询。
要做到这一点，最简单的方法是抓取你完成的桌面设计，并在浏览器中打开它。慢慢缩小屏幕，使其更窄。观察设计什么时候开始“断裂”，或者看起来可怕和局促。此时需要一个带有媒体查询的断点。
通常为台式机、平板电脑和手机创建三组媒体查询。但是，如果你的设计在这三个方面都很好，为什么要麻烦地添加三个不同的不必要的媒体查询呢?根据需要来做!
Twitter Bootstrap推荐的最佳断点
/* Custom, iPhone Retina */
@media only screen and (min-width : 320px) {
}
/* Extra Small Devices, Phones */
@media only screen and (min-width : 480px) {
}
/* Small Devices, Tablets */
@media only screen and (min-width : 768px) {
}
/* Medium Devices, Desktops */
@media only screen and (min-width : 992px) {
}
/* Large Devices, Wide Screens */
@media only screen and (min-width : 1200px) {
}
来源:https://scotch.io/tutorials/default-sizes-for-twitter-bootstraps-media-queries
用于常见设备断点的媒体查询
/* Smartphones (portrait and landscape) ----------- */
@media only screen and (min-device-width : 320px) and (max-device-width : 480px) {
/* Styles */
}
/* Smartphones (landscape) ----------- */
@media only screen and (min-width : 321px) {
/* Styles */
}
/* Smartphones (portrait) ----------- */
@media only screen and (max-width : 320px) {
/* Styles */
}
/* iPads (portrait and landscape) ----------- */
@media only screen and (min-device-width : 768px) and (max-device-width : 1024px) {
/* Styles */
}
/* iPads (landscape) ----------- */
@media only screen and (min-device-width : 768px) and (max-device-width : 1024px) and (orientation : landscape) {
/* Styles */
}
/* iPads (portrait) ----------- */
@media only screen and (min-device-width : 768px) and (max-device-width : 1024px) and (orientation : portrait) {
/* Styles */
}
/**********
iPad 3
**********/
@media only screen and (min-device-width : 768px) and (max-device-width : 1024px) and (orientation : landscape) and (-webkit-min-device-pixel-ratio : 2) {
/* Styles */
}
@media only screen and (min-device-width : 768px) and (max-device-width : 1024px) and (orientation : portrait) and (-webkit-min-device-pixel-ratio : 2) {
/* Styles */
}
/* Desktops and laptops ----------- */
@media only screen and (min-width : 1224px) {
/* Styles */
}
/* Large screens ----------- */
@media only screen and (min-width : 1824px) {
/* Styles */
}
/* iPhone 4 ----------- */
@media only screen and (min-device-width : 320px) and (max-device-width : 480px) and (orientation : landscape) and (-webkit-min-device-pixel-ratio : 2) {
/* Styles */
}
@media only screen and (min-device-width : 320px) and (max-device-width : 480px) and (orientation : portrait) and (-webkit-min-device-pixel-ratio : 2) {
/* Styles */
}
/* iPhone 5 ----------- */
@media only screen and (min-device-width: 320px) and (max-device-height: 568px) and (orientation : landscape) and (-webkit-device-pixel-ratio: 2){
/* Styles */
}
@media only screen and (min-device-width: 320px) and (max-device-height: 568px) and (orientation : portrait) and (-webkit-device-pixel-ratio: 2){
/* Styles */
}
/* iPhone 6 ----------- */
@media only screen and (min-device-width: 375px) and (max-device-height: 667px) and (orientation : landscape) and (-webkit-device-pixel-ratio: 2){
/* Styles */
}
@media only screen and (min-device-width: 375px) and (max-device-height: 667px) and (orientation : portrait) and (-webkit-device-pixel-ratio: 2){
/* Styles */
}
/* iPhone 6+ ----------- */
@media only screen and (min-device-width: 414px) and (max-device-height: 736px) and (orientation : landscape) and (-webkit-device-pixel-ratio: 2){
/* Styles */
}
@media only screen and (min-device-width: 414px) and (max-device-height: 736px) and (orientation : portrait) and (-webkit-device-pixel-ratio: 2){
/* Styles */
}
/* Samsung Galaxy S3 ----------- */
@media only screen and (min-device-width: 320px) and (max-device-height: 640px) and (orientation : landscape) and (-webkit-device-pixel-ratio: 2){
/* Styles */
}
@media only screen and (min-device-width: 320px) and (max-device-height: 640px) and (orientation : portrait) and (-webkit-device-pixel-ratio: 2){
/* Styles */
}
/* Samsung Galaxy S4 ----------- */
@media only screen and (min-device-width: 320px) and (max-device-height: 640px) and (orientation : landscape) and (-webkit-device-pixel-ratio: 3){
/* Styles */
}
@media only screen and (min-device-width: 320px) and (max-device-height: 640px) and (orientation : portrait) and (-webkit-device-pixel-ratio: 3){
/* Styles */
}
/* Samsung Galaxy S5 ----------- */
@media only screen and (min-device-width: 360px) and (max-device-height: 640px) and (orientation : landscape) and (-webkit-device-pixel-ratio: 3){
/* Styles */
}
@media only screen and (min-device-width: 360px) and (max-device-height: 640px) and (orientation : portrait) and (-webkit-device-pixel-ratio: 3){
/* Styles */
}
在我看来，这些是最好的断点:
@media (min-width:320px) { /* smartphones, portrait iPhone, portrait 480x320 phones (Android) */ }
@media (min-width:480px) { /* smartphones, Android phones, landscape iPhone */ }
@media (min-width:600px) { /* portrait tablets, portrait iPad, e-readers (Nook/Kindle), landscape 800x480 phones (Android) */ }
@media (min-width:801px) { /* tablet, landscape iPad, lo-res laptops ands desktops */ }
@media (min-width:1025px) { /* big landscape tablets, laptops, and desktops */ }
@media (min-width:1281px) { /* hi-res laptops and desktops */ }
编辑:改进工作更好的960网格:
@media (min-width:320px) { /* smartphones, iPhone, portrait 480x320 phones */ }
@media (min-width:481px) { /* portrait e-readers (Nook/Kindle), smaller tablets @ 600 or @ 640 wide. */ }
@media (min-width:641px) { /* portrait tablets, portrait iPad, landscape e-readers, landscape 800x480 or 854x480 phones */ }
@media (min-width:961px) { /* tablet, landscape iPad, lo-res laptops ands desktops */ }
@media (min-width:1025px) { /* big landscape tablets, laptops, and desktops */ }
@media (min-width:1281px) { /* hi-res laptops and desktops */ }
在实践中，许多设计师将像素转换为ems，很大程度上是因为ems提供更好的缩放效果。在标准缩放1em == 16px时，将像素乘以1em/16px得到ems。例如，320px === 20em。
对于这条评论的回应，最小宽度是“移动优先”设计的标准，即你从设计最小的屏幕开始，然后添加不断增加的媒体查询，直至越来越大的屏幕。
无论您是喜欢min-、max-还是它们的组合，都要认识到规则的顺序，记住，如果多个规则匹配同一个元素，后面的规则将覆盖前面的规则。
