CSS3: var() 函数（案例：实现卡片主题色）

语法和应用

var(custom-property-name, value)

值	描述
custom-property-name	必需。自定义属性的名称，必需以 -- 开头
value	可选。备用值，在属性不存在的时候使用。

:root {
  --main-bg-color: coral;
  --main-txt-color: blue;
  --main-padding: 15px;
}
 
#div1 {
  background-color: var(--main-bg-color);
  color: var(--main-txt-color);
  padding: var(--main-padding);
}
 
#div2 {
  background-color: var(--main-bg-color);
  color: var(--main-txt-color);
  padding: var(--main-padding);
}

案例：卡片组件

<!-- card.vue -->
<template>
  <div :style="{'--card--theme-color':color}" :class="{theme:color}" class="chart-card">
    <p class="chart-card-title">
      <span>{{ title }}</span>
      <el-tooltip class="item" effect="dark" :content="tips" placement="top">
        <i class="el-icon-info"></i>
      </el-tooltip>
    </p>
    <p class="chart-card-data">{{ countFormat }}</p>
    <div class="chart-card-info">
      <p class="info-item">
        <span class="info-label">环比 </span>
        <span class="info-value">{{data.periodGrowt}}%</span>
      </p>
    </div>
  </div>
</template>

<script>
export default {
  data () {
    return {
      name: ''
    };
  },
  props: {
    title: { // 卡片名称
      type: String, 
      default: '',
    },
    data: {
      type: Object,
      default: {
        count: null, // 值
        periodGrowth: null // 环比
      },
    },
    color: { // 主题颜色
      type: String,
    },
    tips: { // 提示信息
      type: String,
      default: '',
    }
  },
  computed: {
    // 千位展示
    countFormat () {
      if(this.data.count != '-') {
        if(this.data.count > 999){
          const str = this.data.count.toString();
          const reg = /(\d)(?=(?:\d{3})+$)/g;
          return str.replace(reg, '$1,');
        } else {
          return this.data.count
        }
      } else {
        return '--'
      }
    },
  },
};
</script>
<style lang="scss" scoped>
.chart-card{
  background: #ffff;
  border-radius: 4px;
  height: 136px;
  padding: 16px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  p{
    padding: 0;
    margin: 0;
  }
  &-title{
    font-size: 16px;
    color: #797979;
    line-height: 16px;
    display: flex;
    justify-content: space-between;

  }
  &-data{
    color: #333;
    font-size: 32px;
    line-height: 32spx;
    font-weight: bold;
    display: flex;
    justify-content: space-between;
    letter-spacing: 2px;
    i{
      font-size: 16px;
      opacity: 0.8;
    }
  }
  &-info{
    font-size: 14px;
    color: #797979;
    line-height: 14px;
    display: flex;
    justify-content: space-between;
    .el-icon-caret-bottom{
      color: #ef5350;
    }
    .el-icon-caret-top{
      color: #33b86c;
    }
  }
}
.chart-card.theme{
  background: var(--card--theme-color); // 主题颜色应用
  .chart-card-title{
    color: #fff;
    opacity: 0.8;
  }
  .chart-card-data{
    color: #fff;
  }
  .chart-card-info{
    .info-item{
      background:rgba(255, 255, 255, 0.85);
      color: var(--card--theme-color); // 主题颜色应用
      height: 24px;
      line-height: 24px;
      padding: 0 12px;
      border-radius: 12px;
      font-size: 14px;
    }
    .info-value{
      font-weight: bold;
      color: #797979;
    }
  }
}
</style>

应用卡片组件

<chart-card title="告警次数" :data="alarmCardData" color="#29b6f6"/>
<chart-card title="紧急告警次数" :data="urgentCardData" color="#7e57c2"/>
<chart-card title="已处理告警数量" :data="doneCardData" color="#33b86c"/>
<chart-card title="平均处理时长（分钟）" :data="avgCardData" color="#6e8cd7"/>