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){}

引导3

对于Bootstrap 3 (v3.4.1)的最终版本发行版，使用了以下媒体查询，这些查询与概述可用响应类的文档相对应。 https://getbootstrap.com/docs/3.4/css/#responsive-utilities

/* Extra Small Devices, .visible-xs-* */
@media (max-width: 767px) {}

/* Small Devices, .visible-sm-* */
@media (min-width: 768px) and (max-width: 991px) {}

/* Medium Devices, .visible-md-* */
@media (min-width: 992px) and (max-width: 1199px) {}

/* Large Devices, .visible-lg-* */
@media (min-width: 1200px) {}

从Bootstrap GitHub存储库中提取的媒体查询从以下较少的文件

https://github.com/twbs/bootstrap/blob/v3.4.1/less/variables.less#L283 https://github.com/twbs/bootstrap/blob/v3.4.1/less/responsive-utilities.less

引导5

从版本5的文档中可以看到，自版本3以来，媒体查询断点已经更新，以更好地适应现代设备尺寸。

// X-Small devices (portrait phones, less than 576px)
// No media query for `xs` since this is the default in Bootstrap

// Small devices (landscape phones, 576px and up)
@media (min-width: 576px) { ... }

// Medium devices (tablets, 768px and up)
@media (min-width: 768px) { ... }

// Large devices (desktops, 992px and up)
@media (min-width: 992px) { ... }

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

// XX-Large devices (larger desktops, 1400px and up)
@media (min-width: 1400px) { ... }

来源:Bootstrap 5文档

你可以在引导GitHub存储库中看到v5.1.3的断点:-

https://github.com/twbs/bootstrap/blob/v5.1.3/scss/_variables.scss#L461 https://github.com/twbs/bootstrap/blob/v5.1.3/scss/mixins/_breakpoints.scss

更新日期:2021-12-19

@media only screen和(max-width: 1200px) {} @media only screen (max-width: 979px) {} @media only screen (max-width: 767px) {} @media only screen和(max-width: 480px) {} @media only screen and (max-width: 320px) {} @media (min-width: 768px) and (max-width: 991px) {} @media (min-width: 992px) and (max-width: 1024px) {}

如果你正在使用LESS或SCSS/SASS，并且你正在使用Bootstrap的LESS/SCSS版本，你也可以使用变量，只要你能访问它们。@full-decent的答案的LESS翻译如下:

@media(max-width: @screen-xs-max){}
@media(min-width: @screen-sm-min){}  /* deprecated: @screen-tablet, or @screen-sm */
@media(min-width: @screen-md-min){}  /* deprecated: @screen-desktop, or @screen-md */
@media(min-width: @screen-lg-min){}  /* deprecated: @screen-lg-desktop, or @screen-lg */

还有@screen-sm-max和@screen-md-max变量，它们分别比@screen-md-min和@screen-lg-min小1个像素，通常用于@media(max-width)。

编辑:如果你使用SCSS/SASS，变量以$开始，而不是@，所以它会是$screen-xs-max等。

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;
  }
}

或者简单的sas - compass:

@mixin col-xs() {
    @media (max-width: 767px) {
        @content;
    }
}
@mixin col-sm() {
    @media (min-width: 768px) and (max-width: 991px) {
        @content;
    }
}
@mixin col-md() {
    @media (min-width: 992px) and (max-width: 1199px) {
        @content;
    }
}
@mixin col-lg() {
    @media (min-width: 1200px) {
        @content;
    }
}

例子:

#content-box {
    @include border-radius(18px);
    @include adjust-font-size-to(18pt);
    padding:20px;
    border:1px solid red;
    @include col-xs() {
        width: 200px;
        float: none;
    }
}