一、水果拼盘

介绍

目前 CSS3 中新增的 Flex 弹性布局已经成为前端页面布局的首选方案，本题可以使用 Flex 属性快速完成布局。

准备
开始答题前，需要先打开本题的项目代码文件夹，目录结构如下：

├── css
│   └── style.css
├── images
│   ├── apple.svg
│   ├── banana.svg
│   ├── blueplate.svg
│   ├── redplate.svg
│   ├── yellowplate.svg
│   └── pear.svg
└── index.html

其中：

css/style.css 是需要补充的样式文件。
index.html 是主页面。
images 是图片文件夹。
在浏览器中预览 index.html 页面效果如下：

目标
建议使用 flex 相关属性完成 css/style.css 中的 TODO 部分。

1. 禁止修改圆盘的位置和图片的大小。
2. 相同颜色的水果放在相同颜色的圆盘正中间（例如：苹果是红色的就放在红色的圆盘里）。
   完成后，页面效果如下：
   
   代码
   html

    <div id="board"><!-- 水果位置 --><div id="pond"><!-- 苹果 --><div class="fruit apple"><div class="bg animated pulse infinite"></div></div><div class="fruit apple"><div class="bg animated pulse infinite"></div></div><div class="fruit apple"><div class="bg animated pulse infinite"></div></div><div class="fruit apple"><div class="bg animated pulse infinite"></div></div><div class="fruit apple"><div class="bg animated pulse infinite"></div></div><!-- 梨 --><div class="fruit pear"><div class="bg animated pulse infinite"></div></div><div class="fruit pear"><div class="bg animated pulse infinite"></div></div><div class="fruit pear"><div class="bg animated pulse infinite"></div></div><div class="fruit pear"><div class="bg animated pulse infinite"></div></div><div class="fruit pear"><div class="bg animated pulse infinite"></div></div><!-- 香蕉 --><div class="fruit banana"><div class="bg animated pulse infinite"></div></div><div class="fruit banana"><div class="bg animated pulse infinite"></div></div><div class="fruit banana"><div class="bg animated pulse infinite"></div></div><div class="fruit banana"><div class="bg animated pulse infinite"></div></div><div class="fruit banana"><div class="bg animated pulse infinite"></div></div></div><!-- 背景位置 --><div id="fruit-background" style="flex-flow: column wrap"><div class="lilypad apple"><div class="bg"></div></div><div class="lilypad apple"><div class="bg"></div></div><div class="lilypad apple"><div class="bg"></div></div><div class="lilypad apple"><div class="bg"></div></div><div class="lilypad apple"><div class="bg"></div></div><div class="lilypad pear"><div class="bg"></div></div><div class="lilypad pear"><div class="bg"></div></div><div class="lilypad pear"><div class="bg"></div></div><div class="lilypad pear"><div class="bg"></div></div><div class="lilypad pear"><div class="bg"></div></div><div class="lilypad banana"><div class="bg"></div></div><div class="lilypad banana"><div class="bg"></div></div><div class="lilypad banana"><div class="bg"></div></div><div class="lilypad banana"><div class="bg"></div></div><div class="lilypad banana"><div class="bg"></div></div></div></div>

css

/* TODO：待补充代码 */
#pond {
}/* 以下代码不需要修改 */.fruit.apple .bg {background-image: url(../images/apple.svg);
}.fruit.pear .bg {background-image: url(../images/pear.svg);
}.fruit.banana .bg {background-image: url(../images/banana.svg);
}#pond {z-index: 20;
}#pond,
#fruit-background {display: flex;position: absolute;top: 0;left: 0;width: 100%;height: 100%;padding: 1em;
}.lilypad,
.fruit {position: relative;width: 20%;height: 20%;overflow: hidden;
}.lilypad .bg,
.fruit .bg {width: 100%;height: 100%;background-position: center center;background-repeat: no-repeat;
}.animated.infinite {-webkit-animation-iteration-count: infinite;animation-iteration-count: infinite;
}.pulse {-webkit-animation-name: pulse;animation-name: pulse;
}.animated {-webkit-animation-duration: 1s;animation-duration: 1s;-webkit-animation-fill-mode: both;animation-fill-mode: both;
}@-webkit-keyframes pulse {0% {-webkit-transform: scaleX(1);transform: scaleX(1);}50% {-webkit-transform: scale3d(1.05, 1.05, 1.05);transform: scale3d(1.05, 1.05, 1.05);}to {-webkit-transform: scaleX(1);transform: scaleX(1);}
}@keyframes pulse {0% {-webkit-transform: scaleX(1);transform: scaleX(1);}50% {-webkit-transform: scale3d(1.05, 1.05, 1.05);transform: scale3d(1.05, 1.05, 1.05);}to {-webkit-transform: scaleX(1);transform: scaleX(1);}
}.lilypad .bg,
.fruit .bg {width: 100%;height: 100%;background-position: center center;background-size: 80% 80%;background-repeat: no-repeat;
}.fruit .bg {background-size: 30% 30%;
}* {box-sizing: border-box;
}.lilypad.apple .bg {border-radius: 50%;background-image: url(../images/redplate.svg);opacity: 0.6;
}.lilypad.banana .bg {border-radius: 50%;background-image: url(../images/yellowplate.svg);opacity: 0.6;
}.lilypad.pear .bg {border-radius: 50%;opacity: 0.6;background-image: url(../images/blueplate.svg);
}

答案

#pond {/* flex布局 */display: flex;/* 是否换行 默认是不换行  */flex-wrap: wrap;/* 改变主轴 默认是x轴 即row  y是column */flex-direction: column;
}