style: migrate font-size classes to text-[size] syntax

Additionally update spacing utilities and refactor the OrderQrcode component:
- Switch popup implementation from uni-popup to van-popup
- Remove the deprecated SCSS stylesheet
- Clean up component template and script code

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

@@ -9,8 +9,8 @@
                 </div>
             </div>
             <div class="center ml-12">
-                <div class="font-color-900 font-size-14">打开导览地图</div>
-                <div class="font-color-500 font-size-12 mt-6">距你 {{ distance }} · 步行 {{ walk }}</div>
+                <div class="font-color-900 text-[14px]">打开导览地图</div>
+                <div class="font-color-500 text-[12px] mt-6">距你 {{ distance }} · 步行 {{ walk }}</div>
             </div>
             <div class="ml-12 flex flex-items-center flex-justify-center w-32 h-32 rounded-full bg-F2F5F8">
                 <uni-icons class="mb-2" type="right" size="12" color="#99A0AE" />