style(carousel): 优化首屏轮播图切换按钮交互与贴边排版，杜绝文字遮挡

public/assets/addons/official/css/modern_nhc.css

@@ -412,13 +412,13 @@ img {
   opacity: 1;
 }
 
-/* 轮播图左右悬浮控制按钮 (高定毛玻璃气泡) */
+/* 轮播图左右悬浮控制按钮 (优雅悬停显现，不遮挡正文) */
 .nhc-carousel-nav {
   position: absolute;
   top: 50%;
   transform: translateY(-50%);
-  width: 52px;
-  height: 52px;
+  width: 48px;
+  height: 48px;
   border-radius: 50%;
   background: rgba(255, 255, 255, 0.92);
   backdrop-filter: blur(12px);
@@ -432,21 +432,29 @@ img {
   z-index: 10;
   transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
   box-shadow: 0 4px 16px rgba(15, 23, 42, 0.06), 0 1px 2px rgba(15, 23, 42, 0.04);
+  opacity: 0;
+  pointer-events: none;
+}
+
+.nhc-carousel:hover .nhc-carousel-nav {
+  opacity: 0.85;
+  pointer-events: auto;
 }
 
 .nhc-carousel-prev {
-  left: 36px;
+  left: 18px;
 }
 
 .nhc-carousel-next {
-  right: 36px;
+  right: 18px;
 }
 
 .nhc-carousel-nav:hover {
+  opacity: 1 !important;
   background: var(--primary);
   color: #FFFFFF;
   border-color: var(--primary);
-  transform: translateY(-50%) scale(1.1);
+  transform: translateY(-50%) scale(1.08);
   box-shadow: 0 8px 24px rgba(37, 99, 235, 0.35);
 }