我使用Bootstrap 3来构建一个响应式布局,我想根据屏幕大小调整一些字体大小。 我如何使用媒体查询来实现这种逻辑?


当前回答

这些是Bootstrap3的值:

/* Extra Small */
@media(max-width:767px){}

/* Small */
@media(min-width:768px) and (max-width:991px){}

/* Medium */
@media(min-width:992px) and (max-width:1199px){}

/* Large */
@media(min-width:1200px){}

其他回答

这里有一个更简单的一站式解决方案,包括基于媒体查询的独立响应文件。

这允许所有媒体查询逻辑和包含逻辑只存在于一个页面,即加载器。它还允许媒体查询不会使响应式样式表本身混乱。

//loader.less

// this twbs include adds all bs functionality, including added libraries such as elements.less, and our custom variables
@import '/app/Resources/less/bootstrap.less';

/*
* Our base custom twbs overrides
* (phones, xs, i.e. less than 768px, and up)
* no media query needed for this one since this is the default in Bootstrap
* All styles initially go here.  When you need a larger screen override, move those     
* overrides to one of the responsive files below
*/
@import 'base.less';

/*
* Our responsive overrides based on our breakpoint vars
*/
@import url("sm-min.less") (min-width: @screen-sm-min); //(tablets, 768px and up)
@import url("md-min.less") (min-width: @screen-md-min); //(desktops, 992px and up)
@import url("large-min.less") (min-width: @screen-lg-min); //(large desktops, 1200px and up)

基地。更少的会像这样

/**
* base.less
* bootstrap overrides
* Extra small devices, phones, less than 768px, and up
* No media query since this is the default in Bootstrap
* all master site styles go here
* place any responsive overrides in the perspective responsive sheets themselves
*/
body{
  background-color: @fadedblue;
}

sm-min。更少的会像这样

/**
* sm-min.less
* min-width: @screen-sm-min
* Small devices (tablets, 768px and up)
*/
body{
  background-color: @fadedgreen;
}

你的索引只需要加载loader。less

<link rel="stylesheet/less" type="text/css" href="loader.less" />

很简单…

根据其他用户的回答,我编写了这些自定义mixin,以便于使用:

减少输入

.when-xs(@rules) { @media (max-width: @screen-xs-max) { @rules(); } }
.when-sm(@rules) { @media (min-width: @screen-sm-min) { @rules(); } }
.when-md(@rules) { @media (min-width: @screen-md-min) { @rules(); } }
.when-lg(@rules) { @media (min-width: @screen-lg-min) { @rules(); } }

示例使用

body {
  .when-lg({
    background-color: red;
  });
}

SCSS输入

@mixin when-xs() { @media (max-width: $screen-xs-max) { @content; } }
@mixin when-sm() { @media (min-width: $screen-sm-min) { @content; } }
@mixin when-md() { @media (min-width: $screen-md-min) { @content; } }
@mixin when-lg() { @media (min-width: $screen-lg-min) { @content; } }

使用示例:

body {
  @include when-md {
    background-color: red;
  }
}

输出

@media (min-width:1200px) {
  body {
    background-color: red;
  }
}

在我的例子中,你可以看到字体大小和背景颜色根据屏幕大小而变化

<!DOCTYPE html> <html> <head> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <style> body { background-color: lightgreen; } /* Custom, iPhone Retina */ @media(max-width:320px){ body { background-color: lime; font-size:14px; } } @media only screen and (min-width : 320px) { body { background-color: red; font-size:18px; } } /* Extra Small Devices, Phones */ @media only screen and (min-width : 480px) { body { background-color: aqua; font-size:24px; } } /* Small Devices, Tablets */ @media only screen and (min-width : 768px) { body { background-color: green; font-size:30px; } } /* Medium Devices, Desktops */ @media only screen and (min-width : 992px) { body { background-color: grey; font-size:34px; } } /* Large Devices, Wide Screens */ @media only screen and (min-width : 1200px) { body { background-color: black; font-size:42px; } } </style> </head> <body> <p>Resize the browser window. When the width of this document is larger than the height, the background-color is "lightblue", otherwise it is "lightgreen".</p> </body> </html>

我们在Less文件中使用以下媒体查询在网格系统中创建关键断点。

/* Small devices (tablets, 768px and up) */
@media (min-width: @screen-sm-min) { ... }

/* Medium devices (desktops, 992px and up) */
@media (min-width: @screen-md-min) { ... }

/* Large devices (large desktops, 1200px and up) */
@media (min-width: @screen-lg-min) { ... }

参见Bootstrap

引导3

下面是BS3中使用的选择器,如果你想保持一致的话:

@media(max-width:767px){}
@media(min-width:768px){}
@media(min-width:992px){}
@media(min-width:1200px){}

注意:供参考,这可能对调试有用:

<span class="visible-xs">SIZE XS</span>
<span class="visible-sm">SIZE SM</span>
<span class="visible-md">SIZE MD</span>
<span class="visible-lg">SIZE LG</span>

引导4

下面是BS4中使用的选择器。BS4中没有“最低”设置,因为“特小”是默认设置。也就是说,你会首先编码XS的大小,然后有这些媒体覆盖之后。

@media(min-width:576px){}
@media(min-width:768px){}
@media(min-width:992px){}
@media(min-width:1200px){}

引导5

@media(min-width:576px){}
@media(min-width:768px){}
@media(min-width:992px){}
@media(min-width:1200px){}
@media(min-width:1400px){}

更新2021-05-20:版本3.4.1,4.6.0,5.0.0的信息仍然准确。