feat: 为 App.vue 组件新增背景动画元素，优化背景样式，并实现随机生成元素位置的功能，同时添加暗色模式适配和动画性能优化。

src/App.vue

@@ -1,5 +1,11 @@
 <template>
   <div class="app-container">
+    <!-- 背景动画元素 -->
+    <div class="background-animation">
+      <div v-for="n in 12" :key="n" class="floating-element" :style="{ '--delay': `${n * 2}s` }"></div>
+      <div v-for="n in 8" :key="`bubble-${n}`" class="floating-bubble" :style="{ '--delay': `${n * 3}s` }"></div>
+    </div>
+    
     <!-- 3D粒子背景 -->
     <ParticleBackground />
     
@@ -43,22 +49,110 @@
 </template>
 
 <script setup>
-import { ref } from 'vue'
+import { ref, onMounted, onUnmounted } from 'vue'
 import ParticleBackground from './components/ParticleBackground.vue'
 import SocialLinks from './components/SocialLinks.vue'
 import Typewriter from './components/Typewriter.vue'
 import WechatModal from './components/WechatModal.vue'
 
 const showWechatModal = ref(false)
+
+// 随机生成元素的初始位置
+onMounted(() => {
+  const elements = document.querySelectorAll('.floating-element, .floating-bubble')
+  elements.forEach(el => {
+    el.style.left = `${Math.random() * 100}vw`
+    el.style.top = `${Math.random() * 100}vh`
+  })
+})
 </script>
 
 <style scoped>
 .app-container {
   min-height: 100vh;
+  background: linear-gradient(135deg, #e0f7fa 0%, #f3e5f5 100%);
   position: relative;
   overflow: hidden;
 }
 
+.background-animation {
+  position: fixed;
+  inset: 0;
+  pointer-events: none;
+  z-index: 0;
+}
+
+.floating-element {
+  position: absolute;
+  width: 60px;
+  height: 60px;
+  background: linear-gradient(45deg, rgba(255,255,255,0.4), rgba(255,255,255,0.1));
+  border-radius: 20% 60% 40% 80%;
+  animation: float 20s linear infinite;
+  animation-delay: var(--delay);
+  opacity: 0.6;
+  backdrop-filter: blur(2px);
+}
+
+.floating-bubble {
+  position: absolute;
+  width: 40px;
+  height: 40px;
+  background: radial-gradient(circle at 30% 30%, rgba(255,255,255,0.8), rgba(255,255,255,0.1));
+  border-radius: 50%;
+  animation: bubble 15s ease-in-out infinite;
+  animation-delay: var(--delay);
+  opacity: 0.4;
+}
+
+@keyframes float {
+  0% {
+    transform: translate(-100px, 100vh) rotate(0deg);
+  }
+  100% {
+    transform: translate(calc(100vw + 100px), -100px) rotate(360deg);
+  }
+}
+
+@keyframes bubble {
+  0%, 100% {
+    transform: translate(
+      calc(random(100) * 1vw),
+      calc(100vh + 50px)
+    );
+  }
+  50% {
+    transform: translate(
+      calc(random(100) * 1vw),
+      -50px
+    );
+  }
+}
+
+/* 暗色模式适配 */
+@media (prefers-color-scheme: dark) {
+  .app-container {
+    background: linear-gradient(135deg, #263238 0%, #1a237e 100%);
+  }
+  
+  .floating-element {
+    background: linear-gradient(45deg, rgba(255,255,255,0.1), rgba(255,255,255,0.05));
+  }
+  
+  .floating-bubble {
+    background: radial-gradient(circle at 30% 30%, rgba(255,255,255,0.2), rgba(255,255,255,0.05));
+  }
+}
+
+/* 优化动画性能 */
+@media (prefers-reduced-motion: reduce) {
+  .floating-element,
+  .floating-bubble {
+    animation: none;
+    display: none;
+  }
+}
+
 .content {
   position: relative;
   z-index: var(--z-index-content);