置中篇 - 範例

這篇主要簡單帶過幾種置中的方式：

範例１、Display - Flex

HTML

    <div class="main">
        <div class="box"></div>
    </div>

CSS

        *,*::after,*::before
        {

            box-sizing: border-box;
        }
        body{
            margin: 0;
            padding: 0;
        }
        .main{
            position: relative;
            height: 100vh;
            background-color: #555;
            display: flex;
            justify-content: center;
            align-items: center;
        }
        .box{
            position: relative;
            height: 200px;
            width: 200px;

            background-color: plum;
        }

範例２、Display - Grid

HTML

    <div class="main">
        <div class="box"></div>
    </div>

CSS

        *,*::after,*::before
        {

            box-sizing: border-box;
        }
        body{
            margin: 0;
            padding: 0;
        }
        .main{
            position: relative;
            height: 100vh;
            background-color: #555;
            display: grid;

        }
        .box{
            position: relative;
            height: 200px;
            width: 200px;
            justify-self: center;
            align-self: center;
            background-color: plum;
        }

範例２－１

HTML

    <div class="main">
        <div class="box"></div>
    </div>

CSS

        *,*::after,*::before
        {

            box-sizing: border-box;
        }
        body{
            margin: 0;
            padding: 0;
        }
        .main{
            position: relative;
            height: 100vh;
            background-color: #555;
            display: grid;
        }
        .box{
            position: relative;
            height: 200px;
            width: 200px;
            margin: auto;
            background-color: plum;
        }

範例２－２

HTML

    <div class="main">
        <div class="box"></div>
    </div>

CSS

        *,*::after,*::before
        {

            box-sizing: border-box;
        }
        body{
            margin: 0;
            padding: 0;
        }
        .main{
            position: relative;
            height: 100vh;
            background-color: #555;
            display: grid;
        }
        .box{
            position: relative;
            height: 200px;
            width: 200px;
            margin: auto;
            background-color: plum;
        }

範例３position -relative

HTML

    <div class="wrap">
        <div class="box"></div>
    </div>

CSS

        body {
            margin: 0;
            padding: 0;
            background-color: #555;
        }

        .wrap {
            position: relative;
            width: 1200px;
            height: 100vh;
            margin-left: auto;
            margin-right: auto;
            background-color: #aaa;
        }

        .box {
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            margin: auto;
            position: fixed;
            width: 200px;
            height: 200px;
            background-color: #fff;

        }

範例３－１

HTML

    <div class="wrap">
        <div class="box"></div>
    </div>

CSS

        body {
            margin: 0;
            padding: 0;
            background-color: #555;
        }

        .wrap {
            position: relative;
            width: 1200px;
            height: 100vh;
            margin-left: auto;
            margin-right: auto;
            background-color: #aaa;
        }

        .box {
            position: fixed;
            left: 50%;
            top: 50%;
            transform:translate(-50%,-50%);
            width: 200px;
            height: 200px;
            background-color: #fff;
        }

範例３－２

HTML

    <div class="main">
        <div class="box"></div>
    </div>

CSS

        *,*::after,*::before
        {
            box-sizing: border-box;
        }
        body{
            margin: 0;
            padding: 0;
        }
        .main{
            position: relative;
            height: 100vh;
            background-color: #555;
        }
        .box{
            position: relative;
            height: 200px;
            width: 200px;
            top: 50%;
            left: 50%;
            transform: translate(-50%,-50%);
            background-color: plum;
        }