高级css技巧 - 7.常见布局技巧 - 《前端入门 Html5 Css3 移动Web_》

1.margin负值的运用
- 例子1：解决盒子与盒子之间的边框叠加
  - 代码
- 例子2：解决hover后显示有些边框颜色看不到变化的问题
  - 代码
2.文字围绕浮动元素
- 代码
3行内块的巧妙运用
4.css三角强化
- 制作三角
  - 总代码
- 实战

1.margin负值的运用

例子1：解决盒子与盒子之间的边框叠加

代码

<!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>Document</title>
  <style>
    li {
      float: left;
      list-style: none;
      width: 150px;
      height: 200px;
      border: 1px solid blue;
      margin-left: -1px;
    }
  </style>
</head>
<body>
  <ul>
    <li>1</li>
    <li>1</li>
    <li>1</li>
    <li>1</li>
    <li>1</li>
  </ul>
</body>
</html>

例子2：解决hover后显示有些边框颜色看不到变化的问题

出现这种问题是因为例子1：
让每个盒子margin 往左侧移动 -1px 正好压住相邻盒子边框

解决方法： 鼠标经过某个盒子的时候，提高当前盒子的层级即可（如果没有定位，则加相对定位（保留位置），如果有定位，则加z-index）

代码

<!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>Document</title>

  <style>
    li {
      position: relative;

      float: left;
      list-style: none;
      width: 150px;
      height: 200px;
      border: 1px solid blue;
      margin-left: -1px;
    }

    ul li:hover {
      /* position: relative; */
      z-index: 1;
      border: 1px solid red;

    }
  </style>
</head>

<body>

  <ul>
    <li>1</li>
    <li>1</li>
    <li>1</li>
    <li>1</li>
    <li>1</li>
  </ul>

</body>

</html>

2.文字围绕浮动元素

巧妙运用浮动元素不会压住文字的特性，来实现这一效果。

代码

<!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>Document</title>

  <style>
    * {
      margin: 0;
      padding: 0;
    }

    .box {
      padding: 10px 0;
      width: 270px;
      height: 100px;
      background-color: #f7f8f9;
    }

    .box img {
      float: left;
      height: 100px;
      margin-right: 10px;
    }
  </style>
</head>

<body>
  <div class="box">
    <div>
      <img src="demo37.jpg" alt="">
    </div>
    <p>地球正在变暗！20年来不断变暗，地球究竟怎么了？</p>
  </div>
</body>

</html>

3行内块的巧妙运用

4.css三角强化

视频：https://www.bilibili.com/video/BV1pE411q7FU?p=271

制作三角

代码：

    div {
      width: 0;
      height: 0;
      border-top: 100px solid blue;
      border-right: 100px solid red;
      border-bottom: 100px solid green;
      border-left: 100px solid yellow;
    }

border-bottom: 100px solid green 改为
border-bottom: 0 solid green

再把 border-left: 100px solid yellow 改为
border-left: 0 solid yellow

border-top: 100px solid blue 变高
border-top: 200px solid blue;

border-top: 100px solid blue 变透明
border-top: 100px solid transparent
或
border-right: 100px solid red 变透明
border-right: 100px solid transparent

总代码

推荐后面的代码，好维护

<!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>Document</title>

  <style>
    div {
      width: 0;
      height: 0;
      /* border-top: 200px solid transparent;
      border-right: 100px solid red;
      border-bottom: 0 solid green;
      border-left: 0 solid yellow; */

      border-color: transparent red transparent transparent;
      border-style: solid;
      border-width: 200px 100px 0 0;
    }
  </style>
</head>

<body>
  <div></div>
</body>

</html>

实战

<!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>Document</title>

  <style>
    * {
      margin: 0;
      padding: 0;
    }


    .price {
      width: 180px;
      height: 25px;
      border: 1px solid red;
      line-height: 25px;
      margin: 0 auto;
    }

    .price .miaosha {
      position: relative;
      float: left;
      padding-left: 10px;
      margin-left: 0;
      margin-right: 5px;
      width: 85px;
      height: 100%;
      color: #fefffe;
      background-color: red;
    }

    .price .origin {
      color: #a4a7a4;
      font-size: 14px;
      text-decoration: line-through;
    }

    .price .miaosha i {
      position: absolute;
      right: 0;
      width: 0;
      height: 0;
      border-color: transparent #fff transparent transparent;
      border-style: solid;
      border-width: 25px 10px 0 0;
    }
  </style>
</head>

<body>

  <div class="price">
    <span class="miaosha">
      ¥9180.00
      <i></i>
    </span>
    <span class="origin">¥10200.00</span>
  </div>
</body>

</html>