style(mini): 底部导航中间按钮去除异形外框，只保留logo

- 移除 home-blob 异形底座（白色背景+蓝色边框+阴影）
- 移除 jsx 中的 home-blob 元素
- logo 阴影从 box-shadow 改为 filter: drop-shadow，避免透明PNG出现方形阴影
- 正常态：logo 92rpx + 柔和粉紫 drop-shadow
- 激活态：logo 放大1.1倍 + 更强粉紫发光 drop-shadow
- 保留 margin-top:-30rpx 凸起效果

miniprogram/src/custom-tab-bar/index.jsx

@@ -51,7 +51,6 @@ export default class CustomTabBar extends Component {
                   className={`tab-item tab-item--home${active ? ' tab-item--active' : ''}`}
                   onClick={() => this.switchTab(item, index)}
                 >
-                  <View className="home-blob" />
                   <View className="home-inner">
                     <Image className="home-logo" src={opcLogo} mode="aspectFit" />
                   </View>

miniprogram/src/custom-tab-bar/index.scss

@@ -79,28 +79,11 @@
   letter-spacing: 1rpx;
 }
 
-/* ---------- 居中首页：凸起 + 异形辉光底座 ---------- */
+/* ---------- 居中首页：仅 logo 凸起，无外框 ---------- */
 .tab-item--home {
   margin-top: -30rpx;
   z-index: 2;
   justify-content: flex-start;
-  color: rgba(98, 132, 255, 0.55);
-}
-
-.home-blob {
-  position: absolute;
-  top: 0;
-  left: 50%;
-  transform: translateX(-50%);
-  width: 112rpx;
-  height: 108rpx;
-  /* 上圆下收的异形（水滴/倒角蛋形） */
-  border-radius: 52% 52% 44% 44% / 58% 58% 42% 42%;
-  background: linear-gradient(180deg, #ffffff, #eef1ff 72%);
-  border: 2rpx solid rgba(98, 132, 255, 0.30);
-  box-shadow:
-    0 8rpx 26rpx rgba(59, 79, 125, 0.16),
-    inset 0 0 22rpx rgba(98, 132, 255, 0.1);
 }
 
 .home-inner {
@@ -112,38 +95,19 @@
   flex-direction: column;
   align-items: center;
   justify-content: center;
-  text-align: center;
-  padding-top: 0;
 }
 
 .home-logo {
-  width: 88rpx;
-  height: 88rpx;
-  box-shadow: 0 6rpx 20rpx rgba(147,112,219,0.35);
-  transition: transform 0.2s ease, box-shadow 0.2s ease;
-}
-
-/* 激活：底座点亮 + 星星辉光 */
-.tab-item--home.tab-item--active {
-  color: #6284ff;
+  width: 92rpx;
+  height: 92rpx;
+  filter: drop-shadow(0 4rpx 14rpx rgba(147,112,219,0.30));
+  transition: transform 0.2s ease, filter 0.2s ease;
 }
 
+/* 激活态：logo 放大 + 更强发光 */
 .tab-item--home.tab-item--active .home-logo {
-  transform: scale(1.08);
-  box-shadow: 0 8rpx 28rpx rgba(147,112,219,0.5);
-}
-
-.tab-item--home.tab-item--active .home-blob {
-  border-color: rgba(98, 132, 255, 0.9);
-  box-shadow:
-    0 0 36rpx rgba(98, 132, 255, 0.45),
-    0 8rpx 26rpx rgba(0, 0, 0, 0.5),
-    inset 0 0 28rpx rgba(98, 132, 255, 0.22);
-}
-
-.tab-item--home.tab-item--active .ic-star {
-  filter: drop-shadow(0 0 10rpx rgba(98, 132, 255, 0.9));
-  transform: scale(1.12);
+  transform: scale(1.1);
+  filter: drop-shadow(0 6rpx 20rpx rgba(147,112,219,0.50));
 }
 
 /* ---------- 图标（使用 public/ SVG，经 mask 渲染，随 currentColor 变色） ---------- */