<div id="app">
  <div class="header">
    <h2>flex-wrap demo</h2>
    <div class="operation-area">
      <button @click="items.push(0)" style="margin-right: 10px;">
        添加元素
      </button>
      <button @click="items.pop()">删除元素</button>
    </div>
  </div>
  <div class="container">
    <div v-for="(info,infoIdx) in list" class="subcontainer">
      <h2>
        {{key}}: {{info.label}}
        <span v-if="infoIdx === 0">(default)</span>
      </h2>
      <div class="flex-container" :style="{[key]: info.value}">
        <div v-for="(item, idx) in items" class="flex-item">{{idx+1}}</div>
      </div>
    </div>
  </div>
</div>

@flex-item-size: 80px;
@flex-item-margin: 12px;

body {
  margin: 0;
}

button {
  display: flex;
  align-items: center;
  padding: 0 15px;
  color: rgb(17, 85, 204);
  border-radius: 500px;
  bottom: 16px;
  cursor: pointer;
  height: 32px;
  justify-content: center;
  min-width: 32px;
  background-color: rgb(255, 255, 255);
  box-shadow: 0 3px 6px rgba(0, 0, 0, 0.16), 0 1px 2px rgba(0, 0, 0, 0.23);
}

.container {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-around;
  width: 600px;
  margin: 0 auto 40px;
  text-align: center;
  color: fade(#1f2d3d, 70%);
}

.header {
  position: sticky;
  top: 0;
  display: flex;
  justify-content: space-between;
  align-items: center;
  width: 100%;
  height: 60px;
  padding: 0 20px;
  box-shadow: 0 1px 5px rgba(0, 0, 0, 0.2);
  background: #fff;
  box-sizing: border-box;
}

.operation-area {
  display: flex;
}

.flex-container {
  display: flex;
  justify-content: center;
  width: 600px;
  padding: 0 10px;
  margin: auto;
  background: fade(#3a506b, 70%);
}

.flex-item {
  display: flex;
  justify-content: center;
  align-items: center;
  height: @flex-item-size;
  width: @flex-item-size;
  margin: @flex-item-margin;
  font-size: 24px;

  &:nth-child(5n + 1) {
    background: #247ba0;
    color: fade(#fff, 70%);
  }
  &:nth-child(5n + 2) {
    background: #70c1b3;
  }
  &:nth-child(5n + 3) {
    background: #b2dbbf;
  }
  &:nth-child(5n + 4) {
    background: #f3ffbd;
  }
  &:nth-child(5n + 5) {
    background: #ff1654;
    color: fade(#fff, 70%);
  }
}

.light {
  color: fade(#fff, 70%);
}

.line {
  position: relative;
  text-align: center;
  margin: 60px 0 40px;

  &:before {
    content: "";
    position: absolute;
    width: 620px;
    height: 1px;
    background: #222;
    left: 0;
    right: 0;
    top: 16px;
    margin: auto;
  }

  .inner {
    position: relative;
    padding: 0 16px;
    background: #fff;
    font-size: 24px;
  }
}

.tips {
  text-align: left;
  margin: 30px 0;
  padding: 10px;
  border: 1px solid #ccc;
}

const data = [
  'nowrap',
  'wrap',
  'wrap-reverse',
];
const formatOptions = (options = []) => {
  if (!Array.isArray(options)) return [];

  return options.map(item => typeof item === 'string' ? { value: item, label: item } : item)
}

new Vue({
  el: '#app',
  data: {
    key: 'flex-wrap',
    items: Array(15).fill(0),
    list: formatOptions(data)
  },
})