feat: 移除多个组件的背景颜色以优化样式

src/components/cards/TorrentItem.vue

@@ -194,7 +194,6 @@ onMounted(() => {
 
 .torrent-item {
   padding: 12px;
-  background-color: rgb(var(--v-theme-surface));
   box-shadow: none;
   margin-block-end: 8px;
   transition: background-color 0.2s ease, transform 0.2s ease;

src/components/cards/UserCard.vue

@@ -282,7 +282,6 @@ onUnmounted(() => {
 .user-card {
   position: relative;
   overflow: hidden;
-  background: rgb(var(--v-theme-surface));
   transition: all 0.3s ease;
 }
 
@@ -341,7 +340,6 @@ onUnmounted(() => {
   justify-content: center;
   border: 1px solid rgba(var(--v-theme-warning), 0.5);
   border-radius: 50%;
-  background: rgb(var(--v-theme-surface));
   block-size: 18px;
   inline-size: 18px;
   margin-block: 0;

src/components/dialog/SearchBarDialog.vue

@@ -843,7 +843,6 @@ onMounted(() => {
 .site-search-card {
   border: 1px solid rgba(var(--v-theme-on-surface), 0.08);
   border-radius: 14px;
-  background-color: rgb(var(--v-theme-surface));
 }
 
 .site-chip {