We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
Change Clock color
Following on from #1411, perhaps the clock colour needs a wee revisit too?

![Screenshot 2022-12-31 at 10 04 46](https://user-images.githubusercontent.com/28237/210132768-00166ecf-0bf3-4486-bc7f-09cc52d46b21.png)


--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `src/textual/widgets/_header.py`
Content:
```
1 from __future__ import annotations
2 
3 from datetime import datetime
4 
5 from rich.text import Text
6 
7 from ..widget import Widget
8 from ..reactive import Reactive, watch
9 
10 
11 class HeaderIcon(Widget):
12     """Display an 'icon' on the left of the header."""
13 
14     DEFAULT_CSS = """
15     HeaderIcon {
16         dock: left;
17         padding: 0 1;
18         width: 8;
19         content-align: left middle;
20     }
21     """
22     icon = Reactive("⭘")
23 
24     def render(self):
25         return self.icon
26 
27 
28 class HeaderClockSpace(Widget):
29     """The space taken up by the clock on the right of the header."""
30 
31     DEFAULT_CSS = """
32     HeaderClockSpace {
33         dock: right;
34         width: 10;
35         padding: 0 1;
36     }
37     """
38 
39     def render(self) -> str:
40         return ""
41 
42 
43 class HeaderClock(HeaderClockSpace):
44     """Display a clock on the right of the header."""
45 
46     DEFAULT_CSS = """
47     HeaderClock {
48         background: $secondary-background-lighten-1;
49         color: $text;
50         text-opacity: 85%;
51         content-align: center middle;
52     }
53     """
54 
55     def on_mount(self) -> None:
56         self.set_interval(1, callback=self.refresh, name=f"update header clock")
57 
58     def render(self):
59         return Text(datetime.now().time().strftime("%X"))
60 
61 
62 class HeaderTitle(Widget):
63     """Display the title / subtitle in the header."""
64 
65     DEFAULT_CSS = """
66     HeaderTitle {
67         content-align: center middle;
68         width: 100%;
69     }
70     """
71 
72     text: Reactive[str] = Reactive("")
73     sub_text = Reactive("")
74 
75     def render(self) -> Text:
76         text = Text(self.text, no_wrap=True, overflow="ellipsis")
77         if self.sub_text:
78             text.append(" — ")
79             text.append(self.sub_text, "dim")
80         return text
81 
82 
83 class Header(Widget):
84     """A header widget with icon and clock.
85 
86     Args:
87         show_clock (bool, optional): True if the clock should be shown on the right of the header.
88     """
89 
90     DEFAULT_CSS = """
91     Header {
92         dock: top;
93         width: 100%;
94         background: $foreground 5%;
95         color: $text;
96         height: 1;
97     }
98     Header.-tall {
99         height: 3;
100     }    
101     """
102 
103     tall = Reactive(False)
104 
105     DEFAULT_CLASSES = ""
106 
107     def __init__(
108         self,
109         show_clock: bool = False,
110         *,
111         name: str | None = None,
112         id: str | None = None,
113         classes: str | None = None,
114     ):
115         super().__init__(name=name, id=id, classes=classes)
116         self.show_clock = show_clock
117 
118     def compose(self):
119         yield HeaderIcon()
120         yield HeaderTitle()
121         yield HeaderClock() if self.show_clock else HeaderClockSpace()
122 
123     def watch_tall(self, tall: bool) -> None:
124         self.set_class(tall, "-tall")
125 
126     def on_click(self):
127         self.toggle_class("-tall")
128 
129     def on_mount(self) -> None:
130         def set_title(title: str) -> None:
131             self.query_one(HeaderTitle).text = title
132 
133         def set_sub_title(sub_title: str) -> None:
134             self.query_one(HeaderTitle).sub_text = sub_title
135 
136         watch(self.app, "title", set_title)
137         watch(self.app, "sub_title", set_sub_title)
138
```
--- END FILES ---

Please first localize the bug based on the issue statement, and then generate a patch according to the `git diff` format fenced by three backticks.

Here is an example:

```diff
diff --git a/examples/server_async.py b/examples/server_async.py
--- a/examples/server_async.py
+++ b/examples/server_async.py
@@ -313,4 +313,4 @@
 
 
 if __name__ == "__main__":
-    asyncio.run(run_async_server("."), debug=True)
+    asyncio.run(run_async_server(), debug=True)
diff --git a/examples/server_sync.py b/examples/server_sync.py
--- a/examples/server_sync.py
+++ b/examples/server_sync.py
@@ -313,5 +313,5 @@
 
 
 if __name__ == "__main__":
-    server = run_sync_server(".")
+    server = run_sync_server()
     server.shutdown()

```

diff --git a/src/textual/widgets/_header.py b/src/textual/widgets/_header.py
--- a/src/textual/widgets/_header.py
+++ b/src/textual/widgets/_header.py
@@ -45,7 +45,7 @@
 
     DEFAULT_CSS = """
     HeaderClock {
-        background: $secondary-background-lighten-1;
+        background: $foreground-darken-1 5%;
         color: $text;
         text-opacity: 85%;
         content-align: center middle;
@@ -97,7 +97,7 @@
     }
     Header.-tall {
         height: 3;
-    }    
+    }
     """
 
     tall = Reactive(False)

{"golden_diff": "diff --git a/src/textual/widgets/_header.py b/src/textual/widgets/_header.py\n--- a/src/textual/widgets/_header.py\n+++ b/src/textual/widgets/_header.py\n@@ -45,7 +45,7 @@\n \n     DEFAULT_CSS = \"\"\"\n     HeaderClock {\n-        background: $secondary-background-lighten-1;\n+        background: $foreground-darken-1 5%;\n         color: $text;\n         text-opacity: 85%;\n         content-align: center middle;\n@@ -97,7 +97,7 @@\n     }\n     Header.-tall {\n         height: 3;\n-    }    \n+    }\n     \"\"\"\n \n     tall = Reactive(False)\n", "issue": "Change Clock color\nFollowing on from #1411, perhaps the clock colour needs a wee revisit too?\r\n\r\n![Screenshot 2022-12-31 at 10 04 46](https://user-images.githubusercontent.com/28237/210132768-00166ecf-0bf3-4486-bc7f-09cc52d46b21.png)\r\n\n", "before_files": [{"content": "from __future__ import annotations\n\nfrom datetime import datetime\n\nfrom rich.text import Text\n\nfrom ..widget import Widget\nfrom ..reactive import Reactive, watch\n\n\nclass HeaderIcon(Widget):\n    \"\"\"Display an 'icon' on the left of the header.\"\"\"\n\n    DEFAULT_CSS = \"\"\"\n    HeaderIcon {\n        dock: left;\n        padding: 0 1;\n        width: 8;\n        content-align: left middle;\n    }\n    \"\"\"\n    icon = Reactive(\"\u2b58\")\n\n    def render(self):\n        return self.icon\n\n\nclass HeaderClockSpace(Widget):\n    \"\"\"The space taken up by the clock on the right of the header.\"\"\"\n\n    DEFAULT_CSS = \"\"\"\n    HeaderClockSpace {\n        dock: right;\n        width: 10;\n        padding: 0 1;\n    }\n    \"\"\"\n\n    def render(self) -> str:\n        return \"\"\n\n\nclass HeaderClock(HeaderClockSpace):\n    \"\"\"Display a clock on the right of the header.\"\"\"\n\n    DEFAULT_CSS = \"\"\"\n    HeaderClock {\n        background: $secondary-background-lighten-1;\n        color: $text;\n        text-opacity: 85%;\n        content-align: center middle;\n    }\n    \"\"\"\n\n    def on_mount(self) -> None:\n        self.set_interval(1, callback=self.refresh, name=f\"update header clock\")\n\n    def render(self):\n        return Text(datetime.now().time().strftime(\"%X\"))\n\n\nclass HeaderTitle(Widget):\n    \"\"\"Display the title / subtitle in the header.\"\"\"\n\n    DEFAULT_CSS = \"\"\"\n    HeaderTitle {\n        content-align: center middle;\n        width: 100%;\n    }\n    \"\"\"\n\n    text: Reactive[str] = Reactive(\"\")\n    sub_text = Reactive(\"\")\n\n    def render(self) -> Text:\n        text = Text(self.text, no_wrap=True, overflow=\"ellipsis\")\n        if self.sub_text:\n            text.append(\" \u2014 \")\n            text.append(self.sub_text, \"dim\")\n        return text\n\n\nclass Header(Widget):\n    \"\"\"A header widget with icon and clock.\n\n    Args:\n        show_clock (bool, optional): True if the clock should be shown on the right of the header.\n    \"\"\"\n\n    DEFAULT_CSS = \"\"\"\n    Header {\n        dock: top;\n        width: 100%;\n        background: $foreground 5%;\n        color: $text;\n        height: 1;\n    }\n    Header.-tall {\n        height: 3;\n    }    \n    \"\"\"\n\n    tall = Reactive(False)\n\n    DEFAULT_CLASSES = \"\"\n\n    def __init__(\n        self,\n        show_clock: bool = False,\n        *,\n        name: str | None = None,\n        id: str | None = None,\n        classes: str | None = None,\n    ):\n        super().__init__(name=name, id=id, classes=classes)\n        self.show_clock = show_clock\n\n    def compose(self):\n        yield HeaderIcon()\n        yield HeaderTitle()\n        yield HeaderClock() if self.show_clock else HeaderClockSpace()\n\n    def watch_tall(self, tall: bool) -> None:\n        self.set_class(tall, \"-tall\")\n\n    def on_click(self):\n        self.toggle_class(\"-tall\")\n\n    def on_mount(self) -> None:\n        def set_title(title: str) -> None:\n            self.query_one(HeaderTitle).text = title\n\n        def set_sub_title(sub_title: str) -> None:\n            self.query_one(HeaderTitle).sub_text = sub_title\n\n        watch(self.app, \"title\", set_title)\n        watch(self.app, \"sub_title\", set_sub_title)\n", "path": "src/textual/widgets/_header.py"}], "after_files": [{"content": "from __future__ import annotations\n\nfrom datetime import datetime\n\nfrom rich.text import Text\n\nfrom ..widget import Widget\nfrom ..reactive import Reactive, watch\n\n\nclass HeaderIcon(Widget):\n    \"\"\"Display an 'icon' on the left of the header.\"\"\"\n\n    DEFAULT_CSS = \"\"\"\n    HeaderIcon {\n        dock: left;\n        padding: 0 1;\n        width: 8;\n        content-align: left middle;\n    }\n    \"\"\"\n    icon = Reactive(\"\u2b58\")\n\n    def render(self):\n        return self.icon\n\n\nclass HeaderClockSpace(Widget):\n    \"\"\"The space taken up by the clock on the right of the header.\"\"\"\n\n    DEFAULT_CSS = \"\"\"\n    HeaderClockSpace {\n        dock: right;\n        width: 10;\n        padding: 0 1;\n    }\n    \"\"\"\n\n    def render(self) -> str:\n        return \"\"\n\n\nclass HeaderClock(HeaderClockSpace):\n    \"\"\"Display a clock on the right of the header.\"\"\"\n\n    DEFAULT_CSS = \"\"\"\n    HeaderClock {\n        background: $foreground-darken-1 5%;\n        color: $text;\n        text-opacity: 85%;\n        content-align: center middle;\n    }\n    \"\"\"\n\n    def on_mount(self) -> None:\n        self.set_interval(1, callback=self.refresh, name=f\"update header clock\")\n\n    def render(self):\n        return Text(datetime.now().time().strftime(\"%X\"))\n\n\nclass HeaderTitle(Widget):\n    \"\"\"Display the title / subtitle in the header.\"\"\"\n\n    DEFAULT_CSS = \"\"\"\n    HeaderTitle {\n        content-align: center middle;\n        width: 100%;\n    }\n    \"\"\"\n\n    text: Reactive[str] = Reactive(\"\")\n    sub_text = Reactive(\"\")\n\n    def render(self) -> Text:\n        text = Text(self.text, no_wrap=True, overflow=\"ellipsis\")\n        if self.sub_text:\n            text.append(\" \u2014 \")\n            text.append(self.sub_text, \"dim\")\n        return text\n\n\nclass Header(Widget):\n    \"\"\"A header widget with icon and clock.\n\n    Args:\n        show_clock (bool, optional): True if the clock should be shown on the right of the header.\n    \"\"\"\n\n    DEFAULT_CSS = \"\"\"\n    Header {\n        dock: top;\n        width: 100%;\n        background: $foreground 5%;\n        color: $text;\n        height: 1;\n    }\n    Header.-tall {\n        height: 3;\n    }\n    \"\"\"\n\n    tall = Reactive(False)\n\n    DEFAULT_CLASSES = \"\"\n\n    def __init__(\n        self,\n        show_clock: bool = False,\n        *,\n        name: str | None = None,\n        id: str | None = None,\n        classes: str | None = None,\n    ):\n        super().__init__(name=name, id=id, classes=classes)\n        self.show_clock = show_clock\n\n    def compose(self):\n        yield HeaderIcon()\n        yield HeaderTitle()\n        yield HeaderClock() if self.show_clock else HeaderClockSpace()\n\n    def watch_tall(self, tall: bool) -> None:\n        self.set_class(tall, \"-tall\")\n\n    def on_click(self):\n        self.toggle_class(\"-tall\")\n\n    def on_mount(self) -> None:\n        def set_title(title: str) -> None:\n            self.query_one(HeaderTitle).text = title\n\n        def set_sub_title(sub_title: str) -> None:\n            self.query_one(HeaderTitle).sub_text = sub_title\n\n        watch(self.app, \"title\", set_title)\n        watch(self.app, \"sub_title\", set_sub_title)\n", "path": "src/textual/widgets/_header.py"}]}