重构前端 Wave0-2 体验基线（05-28-frontend-ux-redesign）

client/src/components/common/PageHeader.tsx

@@ -13,16 +13,16 @@ type PageHeaderProps = {
 
 export function PageHeader({ title, subtitle, actions, eyebrow, meta, className }: PageHeaderProps) {
   return (
-    <header className={cn("flex flex-col gap-4 md:flex-row md:items-end md:justify-between", className)}>
+    <header className={cn("page-header-shell", className)}>
       <div className="min-w-0 max-w-3xl">
         {eyebrow ? (
-          <div className="text-xs font-bold uppercase text-primary">{eyebrow}</div>
+          <div className="page-header-shell__eyebrow">{eyebrow}</div>
         ) : null}
-        <h1 className="mt-1 text-2xl font-semibold text-[var(--color-text-primary)] md:text-3xl">{title}</h1>
-        {subtitle ? <p className="mt-2 text-sm leading-6 text-[var(--color-text-secondary)]">{subtitle}</p> : null}
+        <h1 className="page-header-shell__title">{title}</h1>
+        {subtitle ? <p className="page-header-shell__subtitle">{subtitle}</p> : null}
         {meta ? <div className="mt-3 flex flex-wrap gap-2">{meta}</div> : null}
       </div>
-      {actions ? <div className="flex shrink-0 flex-wrap items-center gap-2">{actions}</div> : null}
+      {actions ? <div className="page-header-shell__actions">{actions}</div> : null}
     </header>
   );
 }