feat: enhance theme customizer with shadow options and update styles

- Added shadow customization options to the theme customizer, allowing users to select from 'none', 'low', 'medium', and 'high'.
- Updated the theme customizer settings interface and default values to include shadow settings.
- Enhanced the CSS variables for shadows in common.scss to support different shadow levels based on user selection.
- Modified the VirtualSlideView component styles to improve layout and scrolling behavior.
- Updated localization files for English, Simplified Chinese, and Traditional Chinese to include new shadow-related terms.
- Adjusted various components to ensure consistent application of shadow styles across the application.

src/components/slide/VirtualSlideView.vue

@@ -140,7 +140,8 @@ function slideNext(next: boolean) {
   if (!element) return
 
   const visibleCount = Math.max(1, Math.trunc(element.clientWidth / itemStep.value))
-  const currentIndex = element.scrollLeft === 0 ? 0 : Math.trunc((element.scrollLeft + itemStep.value / 2) / itemStep.value)
+  const currentIndex =
+    element.scrollLeft === 0 ? 0 : Math.trunc((element.scrollLeft + itemStep.value / 2) / itemStep.value)
   let targetLeft = 0
 
   if (next) {
@@ -345,15 +346,15 @@ watch(
 
 .slider-content-container {
   position: relative;
-  overflow: hidden;
   inline-size: 100%;
 }
 
 .slider-content {
-  overflow: scroll hidden !important;
+  margin-block-end: -8px;
   -ms-overflow-style: none !important;
+  overflow: scroll visible;
   overscroll-behavior-x: contain !important;
-  padding-block: 8px;
+  padding-block: 0 8px;
   padding-inline: 12px;
   scroll-behavior: smooth;
   scrollbar-width: none !important;
@@ -380,6 +381,11 @@ watch(
   flex: 0 0 auto;
 }
 
+.virtual-slide-item,
+.loading-track > * {
+  padding-block-end: 12px;
+}
+
 .nav-button {
   position: absolute;
   z-index: 20;
@@ -399,8 +405,12 @@ watch(
   pointer-events: none;
   text-shadow: 0 1px 2px rgba(0, 0, 0, 10%);
   transform: translateY(-50%);
-  transition: opacity 0.3s ease, transform 0.3s cubic-bezier(0.25, 0.8, 0.25, 1), background-color 0.3s ease,
-    box-shadow 0.3s ease, border-color 0.3s ease;
+  transition:
+    opacity 0.3s ease,
+    transform 0.3s cubic-bezier(0.25, 0.8, 0.25, 1),
+    background-color 0.3s ease,
+    box-shadow 0.3s ease,
+    border-color 0.3s ease;
 
   svg {
     block-size: 22px;