feat: 优化图片全屏展示方案

- 使用aspectFill模式最大化图片利用屏幕空间
- 添加精美相框和渐变背景突出图片效果
- 优化图片容器尺寸计算保持完美比例
- 增强视觉层次感和用户体验

src/pages/index/index.css

@@ -204,7 +204,10 @@
   left: 0;
   width: 100vw;
   height: 100vh;
-  background: #000;
+  background: linear-gradient(135deg, #2c3e50, #34495e);
+  background-image: 
+    radial-gradient(circle at 25% 25%, rgba(255, 255, 255, 0.1) 0%, transparent 50%),
+    radial-gradient(circle at 75% 75%, rgba(255, 255, 255, 0.05) 0%, transparent 50%);
   display: flex;
   flex-direction: column;
   z-index: 1000;
@@ -274,15 +277,44 @@
   justify-content: center;
   width: 100%;
   height: 100%;
-  padding: 0rpx;
+  padding: 0;
   box-sizing: border-box;
+  position: relative;
+  background: radial-gradient(ellipse at center, rgba(0, 0, 0, 0.1) 0%, rgba(0, 0, 0, 0.8) 100%);
+}
+
+.swiper-item::before {
+  content: "";
+  position: absolute;
+  top: 20rpx;
+  left: 20rpx;
+  right: 20rpx;
+  bottom: 160rpx;
+  border-radius: 24rpx;
+  border: 4rpx solid rgba(255, 255, 255, 0.2);
+  box-shadow: 
+    0 0 0 1rpx rgba(255, 255, 255, 0.1),
+    inset 0 0 40rpx rgba(255, 255, 255, 0.05),
+    0 20rpx 60rpx rgba(0, 0, 0, 0.3);
+  pointer-events: none;
+  z-index: 1;
+  background: linear-gradient(
+    135deg,
+    rgba(255, 255, 255, 0.02) 0%,
+    rgba(255, 255, 255, 0.05) 50%,
+    rgba(255, 255, 255, 0.02) 100%
+  );
 }
 
 .fullscreen-image {
-  width: 100%;
-  height: 100%;
-  max-width: 100%;
-  max-height: 100%;
+  width: calc(100% - 40rpx);
+  height: calc(100% - 180rpx);
+  border-radius: 20rpx;
+  position: relative;
+  z-index: 2;
+  margin-top: 20rpx;
+  object-fit: cover;
+  box-shadow: 0 15rpx 50rpx rgba(0, 0, 0, 0.4);
 }
 
 /* 全屏底部 */