CSS .class 选择器

类选择器

<button class="btn btn-primary" @click="search">搜索</button>

.btn {
  display: inline-block;
  padding: 6px 12px;
  margin-bottom: 0;
  font-size: 14px;
  font-weight: normal;
  line-height: 1.42857143;
  text-align: center;
  white-space: nowrap;
  vertical-align: middle;
  -ms-touch-action: manipulation;
      touch-action: manipulation;
  cursor: pointer;
  -webkit-user-select: none;
     -moz-user-select: none;
      -ms-user-select: none;
          user-select: none;
  background-image: none;
  border: 1px solid transparent;
  border-radius: 4px;
}

.btn-default {
  color: #333;
  background-color: #fff;
  border-color: #ccc;
}

后面的样式会覆盖前面的样式；