Flutter UI Displays Wrong color

I am currently trying to adapt my flutter layout to my theme. I want to colour the Top Bar in the same colour as the SideNavBar (Drawer).

I use for both elements as colour/ background colour Theme.of(context).colorScheme.primaryContainer
However, both are displayed differently. (see illustration)

How can I prevent this?
I want to have the top bar in the color of the drawer

My Code:
SideMenu:

@override
  Widget build(BuildContext context) {
    return Drawer(
      backgroundColor: Theme.of(context).colorScheme.primaryContainer,
      elevation: 10,
      shape: const RoundedRectangleBorder(
        borderRadius: BorderRadius.only(
          topRight: Radius.circular(0),
          bottomRight: Radius.circular(0),
        ),
      ),
      child: SingleChildScrollView(
          child: Column(children: [
            DrawerHeader(
              padding: EdgeInsets.zero,
              child: Image.asset("lib/images/logo.png",),
            ),
            DrawerListTile(title: "Dashboard", icon: Icons.dashboard, onTap: () => onMemberPressed(0)),
            DrawerListTile(title: "Member", icon: Icons.group, onTap: () => onMemberPressed(1)),
...
          ])),
    );
  }
}

Member Administration Screen:

@override
  Widget build(BuildContext context) {
    return SafeArea(
      child: Column(
        children: [
            Container(
              color: Theme.of(context).colorScheme.primaryContainer,
              padding: const EdgeInsets.all(10),

              child: Row(
                children: [
                  if (!Responsive.isDesktop(context))
                    IconButton(
                      icon: Icon(Icons.menu,
                          color: Theme.of(context).colorScheme.primary),
                      onPressed: Scaffold.of(context).openDrawer,
                    ),
                  if (!Responsive.isDesktop(context))
                    const SizedBox(
                      width: 20,
                    ),
                  if (!Responsive.isMobile(context))
                    Text(title,
                        style: TextStyle(
                            color: Theme.of(context).colorScheme.onPrimary,
                            fontSize: 20,
                            fontWeight: FontWeight.bold)),
                  if (!Responsive.isMobile(context))
                    Spacer(flex: Responsive.isDesktop(context) ? 2 : 1),
                  const SizedBox(
                    width: 20,
                  ),
                  Expanded(
                    flex: 2,
                    child: TextField(
                      controller: searchController,
                      decoration: InputDecoration(
                        fillColor: Theme.of(context).colorScheme.secondary,
                        filled: true,
                        hintText: "Search",
                        hintStyle: TextStyle(
                          color: Theme.of(context).colorScheme.onSecondary,
                        ),
                        border: const OutlineInputBorder(
                          borderRadius: BorderRadius.all(Radius.circular(10)),
                          borderSide: BorderSide.none,
                        ),
                        suffixIcon: InkWell(
                          onTap: () {
                            setState(() {
                              filter = searchController.text;
                            });
                          },
                          child: Container(
                            padding: EdgeInsets.all(10),
                            margin: EdgeInsets.symmetric(horizontal: 7),
                            decoration: BoxDecoration(
                              color: Theme.of(context)
                                  .colorScheme
                                  .primaryContainer,
                              borderRadius:
                                  BorderRadius.all(Radius.circular(10)),
                            ),
                            child: Icon(
                              Icons.search,
                              color: Theme.of(context).colorScheme.primary,
                            ),
                          ),
                        ),
                      ),
                    ),
                  ),
                ],
            ),
          ),
        ],
      ),
    );
  }