refactor: standardize spacing and update RefundPopup component

- standardize margin spacing across components with explicit pixel values
- replace legacy uni-popup and icons with van-ui equivalents in RefundPopup
- update font weight class to use semantic name in date range selector

src/pages/home/components/AnswerComponent/index.vue

@@ -4,7 +4,7 @@
     <div class="w-full"></div>
     <div class="flex flex-col px-[16px] pt-16 pb-[12px] ">
       <div v-if="tag" class="long-answer-tag">{{ tag }}</div>
-      <div v-if="title" class="flex flex-row flex-items-start flex-justify-start mb-4">
+      <div v-if="title" class="flex flex-row flex-items-start flex-justify-start mb-[4px]">
         <uni-icons class="icon-active" type="fire-filled" size="18" color="opacity" />
         <span class="text-[16px] font-medium span-color-900 ml-6"> {{ title }}</span>
       </div>