style: 美化 CodeMirror 6 搜索面板样式

美化内容：
- 搜索面板：白色背景、圆角输入框、蓝色焦点光环
- 按钮：圆角、hover 高亮、active 蓝色
- 选项按钮（正则/大小写）：圆形、激活时蓝色边框
- 搜索高亮：黄色半透明 + 边框轮廓
- 当前匹配：橙色高亮 + 加粗边框
- 关闭按钮：hover 背景变色
- 替换按钮：与搜索按钮风格统一
- 暗色主题：完整适配所有组件

CSS 类：
- .cm-panel.cm-search — 面板容器
- .cm-textfield — 输入框
- .cm-button — 按钮
- .cm-toggle — 选项按钮
- .cm-active — 激活状态
- .cm-search-info — 结果计数
- .cm-close — 关闭按钮
- .cm-replace/.cm-replaceAll — 替换按钮
- .cm-searchMatch — 匹配高亮

src/renderer/styles/global.css

@@ -206,14 +206,180 @@ html, body {
   outline: none;
 }
 
-/* 搜索高亮 */
+/* ===== CodeMirror 搜索样式美化 ===== */
+
+/* 搜索面板整体 */
+.cm-panel.cm-search {
+  background: var(--bg) !important;
+  border-bottom: 1px solid var(--border) !important;
+  padding: 8px 12px !important;
+  font-family: var(--font-ui) !important;
+  font-size: 13px !important;
+  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
+}
+
+/* 搜索输入框 */
+.cm-panel .cm-textfield {
+  background: var(--bg-secondary) !important;
+  border: 1px solid var(--border) !important;
+  border-radius: 4px !important;
+  padding: 4px 8px !important;
+  font-size: 13px !important;
+  font-family: var(--font-ui) !important;
+  color: var(--text) !important;
+  outline: none !important;
+  transition: border-color 0.15s ease !important;
+  height: 28px !important;
+}
+
+.cm-panel .cm-textfield:focus {
+  border-color: var(--primary) !important;
+  box-shadow: 0 0 0 2px rgba(26, 115, 232, 0.15) !important;
+}
+
+/* 搜索按钮 */
+.cm-panel .cm-button {
+  background: var(--bg-secondary) !important;
+  border: 1px solid var(--border) !important;
+  border-radius: 4px !important;
+  color: var(--text-secondary) !important;
+  font-size: 12px !important;
+  font-family: var(--font-ui) !important;
+  padding: 4px 10px !important;
+  cursor: pointer !important;
+  transition: all 0.15s ease !important;
+  height: 28px !important;
+  line-height: 1 !important;
+}
+
+.cm-panel .cm-button:hover {
+  background: var(--bg-tertiary) !important;
+  color: var(--text) !important;
+  border-color: var(--text-tertiary) !important;
+}
+
+.cm-panel .cm-button:active {
+  background: var(--primary-light) !important;
+  color: var(--primary) !important;
+}
+
+/* 搜索选项按钮（正则、大小写、全字匹配） */
+.cm-panel .cm-toggle {
+  background: transparent !important;
+  border: 1px solid var(--border) !important;
+  border-radius: 4px !important;
+  color: var(--text-tertiary) !important;
+  font-size: 11px !important;
+  font-weight: 600 !important;
+  font-family: var(--font-mono) !important;
+  padding: 4px 6px !important;
+  cursor: pointer !important;
+  transition: all 0.15s ease !important;
+  height: 28px !important;
+  min-width: 28px !important;
+}
+
+.cm-panel .cm-toggle:hover {
+  background: var(--bg-tertiary) !important;
+  color: var(--text) !important;
+}
+
+.cm-panel .cm-toggle.cm-active {
+  background: var(--primary-light) !important;
+  color: var(--primary) !important;
+  border-color: var(--primary) !important;
+}
+
+/* 搜索结果计数 */
+.cm-panel .cm-search-info {
+  color: var(--text-tertiary) !important;
+  font-size: 11px !important;
+  font-family: var(--font-ui) !important;
+  padding: 0 8px !important;
+  white-space: nowrap !important;
+}
+
+/* 关闭按钮 */
+.cm-panel .cm-close {
+  color: var(--text-tertiary) !important;
+  font-size: 16px !important;
+  cursor: pointer !important;
+  padding: 4px !important;
+  border-radius: 4px !important;
+  transition: all 0.15s ease !important;
+}
+
+.cm-panel .cm-close:hover {
+  background: var(--bg-tertiary) !important;
+  color: var(--text) !important;
+}
+
+/* 替换按钮组 */
+.cm-panel .cm-replace,
+.cm-panel .cm-replaceAll {
+  background: var(--bg-secondary) !important;
+  border: 1px solid var(--border) !important;
+  border-radius: 4px !important;
+  color: var(--text-secondary) !important;
+  font-size: 12px !important;
+  padding: 4px 8px !important;
+  cursor: pointer !important;
+  transition: all 0.15s ease !important;
+}
+
+.cm-panel .cm-replace:hover,
+.cm-panel .cm-replaceAll:hover {
+  background: var(--bg-tertiary) !important;
+  color: var(--text) !important;
+}
+
+/* 搜索高亮匹配 */
 .cm-searchMatch {
-  background: rgba(255, 220, 0, 0.35);
+  background: rgba(255, 220, 0, 0.35) !important;
-  border-radius: 2px;
+  border-radius: 2px !important;
+  outline: 1px solid rgba(255, 220, 0, 0.5) !important;
 }
 
 .cm-searchMatch.cm-searchMatch-selected {
-  background: rgba(255, 150, 0, 0.55);
+  background: rgba(255, 150, 0, 0.55) !important;
+  outline: 2px solid rgba(255, 150, 0, 0.8) !important;
+}
+
+/* 暗色主题适配 */
+:root.dark .cm-searchMatch {
+  background: rgba(255, 220, 0, 0.2) !important;
+  outline-color: rgba(255, 220, 0, 0.3) !important;
+}
+
+:root.dark .cm-searchMatch.cm-searchMatch-selected {
+  background: rgba(255, 150, 0, 0.35) !important;
+  outline-color: rgba(255, 150, 0, 0.6) !important;
+}
+
+:root.dark .cm-panel {
+  background: var(--bg-secondary) !important;
+  border-color: var(--border) !important;
+  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3) !important;
+}
+
+:root.dark .cm-panel .cm-textfield {
+  background: var(--bg-tertiary) !important;
+  border-color: var(--border) !important;
+}
+
+:root.dark .cm-panel .cm-button,
+:root.dark .cm-panel .cm-replace,
+:root.dark .cm-panel .cm-replaceAll {
+  background: var(--bg-tertiary) !important;
+  border-color: var(--border) !important;
+  color: var(--text-secondary) !important;
+}
+
+:root.dark .cm-panel .cm-button:hover,
+:root.dark .cm-panel .cm-replace:hover,
+:root.dark .cm-panel .cm-replaceAll:hover {
+  background: var(--border) !important;
+  color: var(--text) !important;
 }
 
 /* Fold gutter */