Flex布局

这是国外大神专门讲flex布局讲的超级细，虽然没有看完
 边玩游戏边学习flex

块级布局侧重垂直方向、行内布局侧重水平方向，flex布局是跟方向无关的
flex布局可以实现空间自动分配、自动对齐(flexible:弹性布局);
flex适用于简单的线性布局，更复杂的布局要交给Grid,这篇文章写的挺好，学到不少。

常用flex属性

flex container(容器)属性？
flex-direaction:方向
flex-wrap:换行
flex-flow:上面另个的简写
justify-content:主轴方向对齐方式
align-items:侧轴对齐方式
align-content:多行/列内容对齐方式(用的少)
flex item属性？
flex-grow:增长比例(空间过多时)
flex-shrink:收缩比例(空间不够时)
flex-basis:默认大小（一般不用）
order:顺序（代替双飞翼）
align-self:自身对齐方式
align-content:多行/列内容对齐方式(用的少)

结合学习内容写个骰子布局

    <html>
    <head>
    <meta charset="utf-8">
    <title></title>
    <style media="screen">
    .first-face {
    display: flex;
    justify-content: center;
    align-items: center;
    }

    .second-face {
    display: flex;
    justify-content: space-between;
    }

    .second-face .pip:nth-of-type(2) {
    align-self: flex-end;
    }

    .third-face {
    display: flex;
    justify-content: space-between;
    }

    .third-face .pip:nth-of-type(2) {
    align-self: center;
    }

    .third-face .pip:nth-of-type(3) {
    align-self: flex-end;
    }

    .fourth-face, .sixth-face {
    display: flex;
    justify-content: space-between;
    }

    .fourth-face .column, .sixth-face .column {
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    }

    .fifth-face {
    display: flex;
    justify-content: space-between;
    }

    .fifth-face .column {
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    }

    .fifth-face .column:nth-of-type(2) {
    justify-content: center;
    }

    /* OTHER STYLES */

    * {
    box-sizing: border-box;
    }

    html, body {
    height: 100%;
    }

    body {
    display: flex;
    align-items: center;
    justify-content: center;
    vertical-align: center;
    flex-wrap: wrap;
    align-content: center;
    font-family: 'Open Sans', sans-serif;
    background: linear-gradient(top, #222, #333);
    }

    [class$="face"] {
    margin: 16px;
    padding: 4px;

    background-color: #e7e7e7;
    width: 104px;
    height: 104px;
    object-fit: contain;

    box-shadow:
        inset 0 5px white,
        inset 0 -5px #bbb,
        inset 5px 0 #d7d7d7,
        inset -5px 0 #d7d7d7;
        border-radius: 10%;
    }

    .pip {
    display: block;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    margin: 4px;
    background-color: #333;
    box-shadow: inset 0 3px #111, inset 0 -3px #555;
    }
    </style>
    </head>
    <body>
    <div class="first-face">
      <span class="pip"></span>
    </div>
    <div class="second-face">
      <span class="pip"></span>
      <span class="pip"></span>
    </div>
    <div class="third-face">
      <span class="pip"></span>
      <span class="pip"></span>
      <span class="pip"></span>
    </div>
    <div class="fourth-face">
      <div class="column">
        <span class="pip"></span>
        <span class="pip"></span>
      </div>
      <div class="column">
        <span class="pip"></span>
        <span class="pip"></span>
      </div>
    </div>
    <div class="fifth-face">
      <div class="column">
        <span class="pip"></span>
        <span class="pip"></span>
      </div>
      <div class="column">
        <span class="pip"></span>
      </div>
      <div class="column">
        <span class="pip"></span>
        <span class="pip"></span>
      </div>
    </div>
    <div class="sixth-face">
      <div class="column">
        <span class="pip"></span>
        <span class="pip"></span>
        <span class="pip"></span>
      </div>
      <div class="column">
        <span class="pip"></span>
        <span class="pip"></span>
        <span class="pip"></span>
      </div>
    </div>
    </body>
    </html>`

效果图