build: add files of vant-cli 2

packages/vant-cli/site/mobile/components/DemoBlock.vue

@@ -0,0 +1,36 @@
+<template>
+  <section class="van-doc-demo-block">
+    <h2 class="van-doc-demo-block__title">{{ title }}</h2>
+    <slot />
+  </section>
+</template>
+
+<script>
+export default {
+  name: 'demo-block',
+
+  props: {
+    title: String
+  }
+};
+</script>
+
+<style lang="less">
+@import '../style/variable';
+
+.van-doc-demo-block {
+  &__title {
+    margin: 0;
+    padding: 32px 16px 16px;
+    color: @van-doc-text-light-blue;
+    font-weight: normal;
+    font-size: 14px;
+  }
+
+  &:first-of-type {
+    .van-doc-demo-block__title {
+      padding-top: 20px;
+    }
+  }
+}
+</style>