一、vw / vh

目标：能够使用vw单位设置网页元素的尺寸

相对单位：相对视口的尺寸计算结果
vw：viewport width
1vw = 1/100视口宽度
vh：viewport height
1vh = 1/100视口高度

目标：实现在不同宽度的设备中，网页元素尺寸等比缩放效果
vw单位尺寸
1.确定设计稿对应的vw尺寸（1/100视口宽度）
查看设计稿宽度 → 确定参考设备宽度 (视口宽度) → 确定vw尺寸（1/100 视口宽度）

2.vw单位的尺寸 = px单位数值 / ( 1/100 视口宽度 )

vh单位尺寸
1.确定设计稿对应的vh尺寸（1/100视口高度）
查看设计稿宽度 → 确定参考设备高度 (视口高度) → 确定vh尺寸（1/100 视口高度）

2.vh单位的尺寸 = px单位数值 / ( 1/100 视口高度 )

思考：开发中，会不会vw和vh混用呢？
不会。 vh是1/100视口高度，全面屏视口高度尺寸大，如果混用可能会导致盒子变形

二、实战演练-bilibili

index.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>B站</title>
    <link rel="stylesheet" href="./css/index.css">
    <link rel="stylesheet" href="./fonts/iconfont.css">
</head>
<body>
    <!-- 1. 头部固定 -->
    <header>
        <div class="top">
            <div class="left">
                <a href="#">
                    <i class="iconfont Navbar_logo"></i>
                </a>
            </div>
            <div class="right">
                <a href="#">
                    <i class="iconfont ic_search_tab"></i>
                </a>
                <a href="#" class="login">
                    <img src="./images/login.png" alt="">
                </a>
                <a href="#" class="download">
                    <img src="./images/download.png" alt="">
                </a>
            </div>
        </div>
        <div class="bottom">
            <div class="tab">
                <ul>
                    <li><a href="#" class="current">首页</a></li>
                    <li><a href="#">首页</a></li>
                    <li><a href="#">首页</a></li>
                    <li><a href="#">首页</a></li>
                    <li><a href="#">首页</a></li>
                </ul>
            </div>
            <div class="more">
                <a href="#">
                    <i class="iconfont general_pulldown_s"></i>
                </a>
            </div>
        </div>
    </header>
    
    <!-- 2. 视频 -->
    <!-- tab: 菜单的个数要和内容的个数相等 -->
    <!-- 视频区域布局 -->
    <section class="video_content">
        <div class="video_list">
            <a href="#">
                <div class="pic">
                    <img src="./images/1.jpg" alt="">
                    <div class="count">
                        <p>
                            <i class="iconfont icon_shipin_bofangshu"></i>
                            <span>132</span>万
                        </p>
                        <p>
                            <i class="iconfont icon_shipin_danmushu"></i>
                            <span>2.4</span>万
                        </p>
                    </div>
                </div>
                <div class="txt ellipsis-2">你活着补刀就是对我最大的侮辱，韩服最强王者组单杀集锦#19</div>
            </a>
            <a href="#">
                <div class="pic">
                    <img src="./images/1.jpg" alt="">
                    <div class="count">
                        <p>
                            <i class="iconfont icon_shipin_bofangshu"></i>
                            <span>132</span>万
                        </p>
                        <p>
                            <i class="iconfont icon_shipin_danmushu"></i>
                            <span>2.4</span>万
                        </p>
                    </div>
                </div>
                <div class="txt ellipsis-2">你活着补刀就是对我最大的侮辱，韩服最强王者组单杀集锦#19</div>
            </a>
            <a href="#">
                <div class="pic">
                    <img src="./images/1.jpg" alt="">
                    <div class="count">
                        <p>
                            <i class="iconfont icon_shipin_bofangshu"></i>
                            <span>132</span>万
                        </p>
                        <p>
                            <i class="iconfont icon_shipin_danmushu"></i>
                            <span>2.4</span>万
                        </p>
                    </div>
                </div>
                <div class="txt ellipsis-2">你活着补刀就是对我最大的侮辱，韩服最强王者组单杀集锦#19</div>
            </a>
            <a href="#">
                <div class="pic">
                    <img src="./images/1.jpg" alt="">
                    <div class="count">
                        <p>
                            <i class="iconfont icon_shipin_bofangshu"></i>
                            <span>132</span>万
                        </p>
                        <p>
                            <i class="iconfont icon_shipin_danmushu"></i>
                            <span>2.4</span>万
                        </p>
                    </div>
                </div>
                <div class="txt ellipsis-2">你活着补刀就是对我最大的侮辱，韩服最强王者组单杀集锦#19</div>
            </a>
            <a href="#">
                <div class="pic">
                    <img src="./images/1.jpg" alt="">
                    <div class="count">
                        <p>
                            <i class="iconfont icon_shipin_bofangshu"></i>
                            <span>132</span>万
                        </p>
                        <p>
                            <i class="iconfont icon_shipin_danmushu"></i>
                            <span>2.4</span>万
                        </p>
                    </div>
                </div>
                <div class="txt ellipsis-2">你活着补刀就是对我最大的侮辱，韩服最强王者组单杀集锦#19</div>
            </a>
            <a href="#">
                <div class="pic">
                    <img src="./images/1.jpg" alt="">
                    <div class="count">
                        <p>
                            <i class="iconfont icon_shipin_bofangshu"></i>
                            <span>132</span>万
                        </p>
                        <p>
                            <i class="iconfont icon_shipin_danmushu"></i>
                            <span>2.4</span>万
                        </p>
                    </div>
                </div>
                <div class="txt ellipsis-2">你活着补刀就是对我最大的侮辱，韩服最强王者组单杀集锦#19</div>
            </a>
            <a href="#">
                <div class="pic">
                    <img src="./images/1.jpg" alt="">
                    <div class="count">
                        <p>
                            <i class="iconfont icon_shipin_bofangshu"></i>
                            <span>132</span>万
                        </p>
                        <p>
                            <i class="iconfont icon_shipin_danmushu"></i>
                            <span>2.4</span>万
                        </p>
                    </div>
                </div>
                <div class="txt ellipsis-2">你活着补刀就是对我最大的侮辱，韩服最强王者组单杀集锦#19</div>
            </a>
            <a href="#">
                <div class="pic">
                    <img src="./images/1.jpg" alt="">
                    <div class="count">
                        <p>
                            <i class="iconfont icon_shipin_bofangshu"></i>
                            <span>132</span>万
                        </p>
                        <p>
                            <i class="iconfont icon_shipin_danmushu"></i>
                            <span>2.4</span>万
                        </p>
                    </div>
                </div>
                <div class="txt ellipsis-2">你活着补刀就是对我最大的侮辱，韩服最强王者组单杀集锦#19</div>
            </a>
            <a href="#">
                <div class="pic">
                    <img src="./images/1.jpg" alt="">
                    <div class="count">
                        <p>
                            <i class="iconfont icon_shipin_bofangshu"></i>
                            <span>132</span>万
                        </p>
                        <p>
                            <i class="iconfont icon_shipin_danmushu"></i>
                            <span>2.4</span>万
                        </p>
                    </div>
                </div>
                <div class="txt ellipsis-2">你活着补刀就是对我最大的侮辱，韩服最强王者组单杀集锦#19</div>
            </a>
            <a href="#">
                <div class="pic">
                    <img src="./images/1.jpg" alt="">
                    <div class="count">
                        <p>
                            <i class="iconfont icon_shipin_bofangshu"></i>
                            <span>132</span>万
                        </p>
                        <p>
                            <i class="iconfont icon_shipin_danmushu"></i>
                            <span>2.4</span>万
                        </p>
                    </div>
                </div>
                <div class="txt ellipsis-2">你活着补刀就是对我最大的侮辱，韩服最强王者组单杀集锦#19</div>
            </a>
        </div>
    </section>
    <!-- 3. 按钮固定 -->
</body>
</html>

index.less

@import 'base';

@vw: 3.75vw;
@color: #fb7299;

// 头部 固定
header {
    position: fixed;
    left: 0;
    top: 0;
    z-index: 1;
    width: 100%;
    height: (84 / @vw);
    background-color: #fff;

    // top
    .top {
        display: flex;
        justify-content: space-between;
        align-items: center;

        height: (44 / @vw);
        padding-left: (18 / @vw);
        padding-right: (12 / @vw);
        // background-color: green;

        .left {
            .iconfont {
                font-size: 28px;
                color: @color;
            }
        }

        .right {
            display: flex;
            .iconfont {
                font-size: (22 / @vw);
                color: #ccc;
            }

            .login {
                width: (24 / @vw);
                height: (24 / @vw);
                margin-left: (24 / @vw);
            }

            .download {
                width: (72 / @vw);
                height: (24 / @vw);
                margin-left: (24 / @vw);
            }
        }
    }

    //bottom
    .bottom {
        display: flex;
        justify-content: space-between;
        height: (40 / @vw);
        border-bottom: 1px solid #eee;
        .more {
            a {
                display: block;
                width: (40 / @vw);
                height: (40 / @vw);
                // background-color: pink;
                text-align: center;
                line-height: (40 / @vw);
                // font-size: (22 / @vw);
                color: #ccc;
                .iconfont {
                    font-size: (22 / @vw);
                }
            }
        }

        .tab {
            ul {
                display: flex;
                li {
                    padding: 0 (16 / @vw);
                    a {
                        display: block;
                        height: (38 / @vw);
                        line-height: (38 / @vw);
                        font-size: (14 / @vw);
                        &.current {
                            color: @color;
                            border-bottom: 2px solid @color;
                        }
                    }
                }
            }
        }
    }
}

// 视频
.video_content {
    padding: (84 / @vw) (5 / @vw) 0;

    .video_list {
        display: flex;
        // 让弹性盒子换行
        flex-wrap: wrap;
        a {
            width: 50%;
            padding: (8 / @vw) (5 / @vw);
            // background-color: pink;
            font-size: (12 / @vw);

            .txt {
                margin-top: (5 / @vw);
            }

            .pic {
                position: relative;
                .count {
                    position: absolute;
                    left: 0;
                    bottom: 0;
                    display: flex;
                    justify-content: space-between;
                    width: 100%;
                    padding: (8 / @vw);
                    background-image: linear-gradient(to top, rgba(0, 0, 0, 0.6), rgba(0, 0, 0, 0));
                    color: #fff;
                    i {
                        vertical-align: middle;
                    }
                }
            }
        }
    }
}

base.less

// out:false

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-font-smoothing: antialiased;
    -webkit-tap-highlight-color: rgba(0,0,0,0);
  }
  
  body {
    font-family: Helvetica Neue,Tahoma,Arial,PingFangSC-Regular,Hiragino Sans GB,Microsoft Yahei,sans-serif;
  }
  
  a {
    color: #333;
    text-decoration: none;
  }
  
  img {
    vertical-align: middle;
    width: 100%;
    height: 100%;
  }
  ul {
    list-style: none;
  }
  
  .ellipsis-2 {
    overflow: hidden;
    text-overflow: ellipsis;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
  }

index.css

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  -webkit-font-smoothing: antialiased;
  -webkit-tap-highlight-color: rgba(0, 0, 0, 0);
}
body {
  font-family: Helvetica Neue, Tahoma, Arial, PingFangSC-Regular, Hiragino Sans GB, Microsoft Yahei, sans-serif;
}
a {
  color: #333;
  text-decoration: none;
}
img {
  vertical-align: middle;
  width: 100%;
  height: 100%;
}
ul {
  list-style: none;
}
.ellipsis-2 {
  overflow: hidden;
  text-overflow: ellipsis;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
}
header {
  position: fixed;
  left: 0;
  top: 0;
  z-index: 1;
  width: 100%;
  height: 22.4vw;
  background-color: #fff;
}
header .top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 11.73333333vw;
  padding-left: 4.8vw;
  padding-right: 3.2vw;
}
header .top .left .iconfont {
  font-size: 28px;
  color: #fb7299;
}
header .top .right {
  display: flex;
}
header .top .right .iconfont {
  font-size: 5.86666667vw;
  color: #ccc;
}
header .top .right .login {
  width: 6.4vw;
  height: 6.4vw;
  margin-left: 6.4vw;
}
header .top .right .download {
  width: 19.2vw;
  height: 6.4vw;
  margin-left: 6.4vw;
}
header .bottom {
  display: flex;
  justify-content: space-between;
  height: 10.66666667vw;
  border-bottom: 1px solid #eee;
}
header .bottom .more a {
  display: block;
  width: 10.66666667vw;
  height: 10.66666667vw;
  text-align: center;
  line-height: 10.66666667vw;
  color: #ccc;
}
header .bottom .more a .iconfont {
  font-size: 5.86666667vw;
}
header .bottom .tab ul {
  display: flex;
}
header .bottom .tab ul li {
  padding: 0 4.26666667vw;
}
header .bottom .tab ul li a {
  display: block;
  height: 10.13333333vw;
  line-height: 10.13333333vw;
  font-size: 3.73333333vw;
}
header .bottom .tab ul li a.current {
  color: #fb7299;
  border-bottom: 2px solid #fb7299;
}
.video_content {
  padding: 22.4vw 1.33333333vw 0;
}
.video_content .video_list {
  display: flex;
  flex-wrap: wrap;
}
.video_content .video_list a {
  width: 50%;
  padding: 2.13333333vw 1.33333333vw;
  font-size: 3.2vw;
}
.video_content .video_list a .txt {
  margin-top: 1.33333333vw;
}
.video_content .video_list a .pic {
  position: relative;
}
.video_content .video_list a .pic .count {
  position: absolute;
  left: 0;
  bottom: 0;
  display: flex;
  justify-content: space-between;
  width: 100%;
  padding: 2.13333333vw;
  background-image: linear-gradient(to top, rgba(0, 0, 0, 0.6), rgba(0, 0, 0, 0));
  color: #fff;
}
.video_content .video_list a .pic .count i {
  vertical-align: middle;
}

在这里插入图片描述

原文链接：https://blog.csdn.net/weixin_45831040/article/details/126795031