fix(export): keep actions sticky and refine headers

src/pages/ExportPage.scss

@@ -1352,6 +1352,21 @@
     justify-content: flex-end;
     gap: 8px;
     flex-shrink: 0;
+    position: sticky;
+    right: 0;
+    z-index: 8;
+    background: color-mix(in srgb, var(--bg-primary) 78%, var(--bg-secondary));
+
+    &::before {
+      content: '';
+      position: absolute;
+      top: 0;
+      bottom: 0;
+      left: -18px;
+      width: 18px;
+      pointer-events: none;
+      background: linear-gradient(to right, transparent, color-mix(in srgb, var(--bg-primary) 82%, var(--bg-secondary)));
+    }
   }
 
   .contacts-list {
@@ -1801,11 +1816,28 @@
   gap: 4px;
   width: var(--contacts-action-col-width);
   flex-shrink: 0;
+  position: sticky;
+  right: 0;
+  z-index: 6;
+  background: inherit;
+
+  &::before {
+    content: '';
+    position: absolute;
+    top: -12px;
+    bottom: -12px;
+    left: -18px;
+    width: 18px;
+    pointer-events: none;
+    background: linear-gradient(to right, transparent, color-mix(in srgb, var(--bg-primary) 84%, var(--bg-secondary)));
+  }
 
   .row-action-main {
     display: inline-flex;
     align-items: flex-start;
     gap: 6px;
+    position: relative;
+    z-index: 1;
 
     &.single-line {
       align-items: center;

src/pages/ExportPage.tsx

@@ -4290,6 +4290,11 @@ function ExportPage() {
     if (activeTab === 'group') return '群聊'
     return '曾经的好友'
   }, [activeTab])
+  const contactsHeaderMainLabel = useMemo(() => {
+    if (activeTab === 'group') return '群聊名称'
+    if (activeTab === 'private' || activeTab === 'former_friend') return '联系人'
+    return '联系人（头像/名称/微信号）'
+  }, [activeTab])
   const shouldShowSnsColumn = useMemo(() => (
     activeTab === 'private' || activeTab === 'former_friend'
   ), [activeTab])
@@ -5677,7 +5682,7 @@ function ExportPage() {
                     </button>
                   </span>
                   <span className="contacts-list-header-main">
-                    <span className="contacts-list-header-main-label">联系人（头像/名称/微信号）</span>
+                    <span className="contacts-list-header-main-label">{contactsHeaderMainLabel}</span>
                   </span>
                   <span className="contacts-list-header-count">总消息数</span>
                   <span className="contacts-list-header-media">表情包</span>