refactor(about): 将v-bind css变量功能抽离为独立组件

将原本在about.vue中的v-bind css变量相关代码抽离到单独的VBindCss组件中，提高代码可维护性

src/pages/about/components/VBindCss.vue

@@ -0,0 +1,27 @@
+<script lang="ts" setup>
+const testBindCssVariable = ref('red')
+function changeTestBindCssVariable() {
+  if (testBindCssVariable.value === 'red') {
+    testBindCssVariable.value = 'green'
+  }
+  else {
+    testBindCssVariable.value = 'red'
+  }
+}
+</script>
+
+<template>
+  <button class="mt-4 w-60 text-center" @click="changeTestBindCssVariable">
+    toggle v-bind css变量
+  </button>
+  <view class="test-css my-2 text-center">
+    测试v-bind css变量的具体文案
+  </view>
+</template>
+
+<style lang="scss" scoped>
+.test-css {
+  color: v-bind(testBindCssVariable);
+  font-size: 24px;
+}
+</style>