style: 统一全站深色视觉

lib/core/widgets/plain_page_scaffold.dart

@@ -3,6 +3,7 @@
 import 'package:flutter/material.dart';
 
 import '../theme/app_colors.dart';
+import '../theme/app_theme.dart';
 import 'subpage_header.dart';
 
 /// 二级页面通用骨架：返回栏 + 标题/副标题 + 可滚动内容，无底部导航。
@@ -27,17 +28,20 @@ class PlainPageScaffold extends StatelessWidget {
     return Scaffold(
       key: pageKey,
       backgroundColor: AppColors.ink,
-      body: SafeArea(
-        child: Column(
-          crossAxisAlignment: CrossAxisAlignment.start,
-          children: [
-            AppSubpageHeader(
-              title: title,
-              subtitle: subtitle,
-              backKey: backKey,
-            ),
-            Expanded(child: child),
-          ],
+      body: DecoratedBox(
+        decoration: const BoxDecoration(gradient: AppTheme.pageGradient),
+        child: SafeArea(
+          child: Column(
+            crossAxisAlignment: CrossAxisAlignment.start,
+            children: [
+              AppSubpageHeader(
+                title: title,
+                subtitle: subtitle,
+                backKey: backKey,
+              ),
+              Expanded(child: child),
+            ],
+          ),
         ),
       ),
     );

lib/core/widgets/subpage_header.dart

@@ -14,9 +14,7 @@ const double _subtitleFontSize = 12;
 const double _actionGap = 8;
 const double _iconSize = 22;
 const double _iconWeight = 600;
-const double _borderWidth = 1;
 const double _shadowBlur = 8;
-const Offset _lightShadowOffset = Offset(0, 2);
 
 /// 二级页面统一圆形操作按钮，返回、分享和更多共用同一尺寸与表面样式。
 class AppSubpageCircleButton extends StatelessWidget {
@@ -47,24 +45,18 @@ class AppSubpageCircleButton extends StatelessWidget {
           key: const Key('subpage-back-shadow'),
           decoration: BoxDecoration(
             shape: BoxShape.circle,
-            boxShadow: [
-              BoxShadow(
-                color: dark ? AppColors.shadowSoft : AppColors.shadowSubtle,
-                blurRadius: _shadowBlur,
-                offset: dark ? Offset.zero : _lightShadowOffset,
-              ),
-            ],
+            boxShadow: dark
+                ? const [
+                    BoxShadow(
+                      color: AppColors.shadowSoft,
+                      blurRadius: _shadowBlur,
+                    ),
+                  ]
+                : const [],
           ),
           child: Material(
-            color: dark ? AppColors.headerScrim : AppColors.card,
-            shape: CircleBorder(
-              side: dark
-                  ? BorderSide.none
-                  : const BorderSide(
-                      color: AppColors.border,
-                      width: _borderWidth,
-                    ),
-            ),
+            color: dark ? AppColors.headerScrim : AppColors.transparent,
+            shape: const CircleBorder(),
             clipBehavior: Clip.antiAlias,
             child: InkWell(
               customBorder: const CircleBorder(),
@@ -72,7 +64,7 @@ class AppSubpageCircleButton extends StatelessWidget {
               child: Center(
                 child: Icon(
                   icon,
-                  color: AppColors.onSurface,
+                  color: dark ? AppColors.onSurface : AppColors.textPrimary,
                   size: _iconSize,
                   weight: _iconWeight,
                 ),
@@ -85,7 +77,7 @@ class AppSubpageCircleButton extends StatelessWidget {
   }
 }
 
-/// 二级页面统一返回按钮，浅色页使用白底描边，深色页使用半透明黑底。
+/// 二级页面统一返回按钮，普通页透明，沉浸页使用半透明黑底。
 class AppSubpageBackButton extends StatelessWidget {
   const AppSubpageBackButton({
     super.key,
@@ -133,8 +125,8 @@ class AppSubpageHeader extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    final foreground = AppColors.onSurface;
-    final secondary = AppColors.muted;
+    final foreground = AppColors.textPrimary;
+    final secondary = AppColors.textSecondary;
     return SizedBox(
       key: const Key('subpage-header'),
       height: subtitle == null ? _height : _heightWithSubtitle,