refactor(theme): 移除侧边栏配色方案并优化主题样式

移除侧边栏配色方案相关代码，统一使用主题变量控制样式
优化表格区域样式，修复布局问题
更新主题色预设，提供更丰富的颜色选择
调整暗黑模式和明亮模式下的样式表现

frontend/src/components/Breadcrumb/index.vue

@@ -76,10 +76,4 @@ onBeforeMount(() => {
 });
 </script>
 
-<style lang="scss" scoped>
-// 覆盖 element-plus 的样式
-.el-breadcrumb__inner,
-.el-breadcrumb__inner a {
-  font-weight: 400 !important;
-}
-</style>
+<style lang="scss" scoped></style>

frontend/src/components/Hamburger/index.vue

@@ -1,42 +1,17 @@
 <!-- 折叠按钮 -->
 <template>
   <div class="hamburger-wrapper" @click="toggleClick">
-    <div :class="['i-svg:collapse', { hamburger: true, 'is-active': isActive }, hamburgerClass]" />
+    <div :class="['i-svg:collapse', { hamburger: true, 'is-active': isActive }]" />
   </div>
 </template>
 
 <script setup lang="ts">
-import { useSettingsStore } from "@/store";
-import { ThemeMode, SidebarColor } from "@/enums/settings/theme.enum";
-import { LayoutMode } from "@/enums/settings/layout.enum";
-
 defineProps({
   isActive: { type: Boolean, required: true },
 });
 
 const emit = defineEmits(["toggleClick"]);
 
-const settingsStore = useSettingsStore();
-const layout = computed(() => settingsStore.layout);
-
-const hamburgerClass = computed(() => {
-  // 如果暗黑主题
-  if (settingsStore.theme === ThemeMode.DARK) {
-    return "hamburger--white";
-  }
-
-  // 如果是混合布局 && 导航背景方案是经典蓝
-  if (
-    layout.value === LayoutMode.MIX &&
-    settingsStore.sidebarColorScheme === SidebarColor.CLASSIC_BLUE
-  ) {
-    return "hamburger--white";
-  }
-
-  // 默认返回空字符串
-  return "";
-});
-
 function toggleClick() {
   emit("toggleClick");
 }
@@ -52,11 +27,12 @@ function toggleClick() {
 
   .hamburger {
     vertical-align: middle;
+    color: var(--el-text-color-secondary);
     transform: scaleX(-1);
-    transition: transform 0.3s ease;
+    transition: all 0.3s ease;
 
-    &--white {
-      color: #fff;
+    &:hover {
+      color: var(--el-color-primary);
     }
 
     &.is-active {

frontend/src/components/IconSelect/index.vue

@@ -196,13 +196,13 @@ onMounted(() => {
   padding: 8px;
   margin: 4px;
   cursor: pointer;
-  border: 1px solid #dcdfe6;
+  border: 1px solid var(--el-border-color);
   border-radius: 4px;
   transition: all 0.3s;
 }
 
 .icon-grid-item:hover {
-  border-color: #4080ff;
+  border-color: var(--el-color-primary);
   transform: scale(1.2);
 }
 </style>