feat(desktop): P26 HUD 常驻元素半透明底色 + 1px 描边（昼/夜可读）

3 files changed, 46 insertions, 5 deletions

diff --git a/src/LivingVillage.Desktop.Tests/P16UiTests.fs b/src/LivingVillage.Desktop.Tests/P16UiTests.fs
index 2e474ac..b68bbd3 100644
--- a/src/LivingVillage.Desktop.Tests/P16UiTests.fs
+++ b/src/LivingVillage.Desktop.Tests/P16UiTests.fs
@@ -128,6 +128,27 @@ type P16HudTests () =
         Assert.IsTrue(ChineseText.requiredUiLabels |> List.contains "体力")
         Assert.IsTrue(ChineseText.requiredUiLabels |> List.contains "钱币")
 
+    [<TestMethod>]
+    member _.HudPersistentSegmentsGetBackdropAndOutlineInBothPeriods () =
+        // P26：白天/夜景两套调色板都要有半透明底色 + 不透明深色描边，保证常驻元素可读。
+        for mode in [ Day; Night ] do
+            let palette = HudLayout.palette mode
+            Assert.IsTrue(palette.SegmentBackdrop.A > 0uy, "segment backdrop must be translucent, not opaque")
+            Assert.IsTrue(palette.SegmentBackdrop.A < 255uy, "segment backdrop must keep the scene visible")
+            Assert.AreEqual<byte>(255uy, palette.Outline.A)
+            Assert.IsTrue(palette.Outline.R < 40uy && palette.Outline.G < 40uy && palette.Outline.B < 40uy)
+            let outlineSum = int palette.Outline.R + int palette.Outline.G + int palette.Outline.B
+            let valueSum = int palette.Value.R + int palette.Value.G + int palette.Value.B
+            Assert.IsTrue(outlineSum < valueSum, "outline must contrast with the bright value text")
+        Assert.AreEqual<int>(4, HudLayout.textOutlineOffsets.Length)
+        for (dx, dy) in HudLayout.textOutlineOffsets do
+            Assert.IsTrue(dx <> 0 || dy <> 0, "outline offset must be non-zero")
+        let placed = HudLayout.layout (HudLayout.segments world SimulationControl.initial)
+        for (x, width, _) in placed do
+            let rect = HudLayout.segmentBackdrop x width
+            Assert.IsTrue(rect.X <= x && rect.X + rect.Width >= x + width, "backdrop must cover the segment text")
+            Assert.IsTrue(rect.Y >= 0 && rect.Y + rect.Height <= HudLayout.barHeight, "backdrop must stay inside the bar")
+
 // ---- P16-FIX 菜单截图帧表 ----
 
 [<TestClass>]
diff --git a/src/LivingVillage.Desktop/Game.fs b/src/LivingVillage.Desktop/Game.fs
index 537ae3b..591d1b9 100644
--- a/src/LivingVillage.Desktop/Game.fs
+++ b/src/LivingVillage.Desktop/Game.fs
@@ -1230,9 +1230,13 @@ type LivingVillageGame() as this =
         spriteBatch.Draw(pixel, Rectangle(0, 0, viewport.Width, barHeight / 2), palette.BarTop)
         spriteBatch.Draw(pixel, Rectangle(0, barHeight / 2, viewport.Width, barHeight - barHeight / 2), palette.BarBottom)
         spriteBatch.Draw(pixel, Rectangle(0, barHeight, viewport.Width, HudLayout.accentHeight), palette.Accent)
-        for (x, _, segment) in placed do
-            PixelText.draw spriteBatch pixel cjkAtlas x textY HudLayout.textScale palette.Label segment.Label
+        for (x, width, segment) in placed do
+            spriteBatch.Draw(pixel, HudLayout.segmentBackdrop x width, palette.SegmentBackdrop)
             let labelAdvanced = FloatingPrompt.measureWidth (segment.Label + " ") HudLayout.textScale
+            for (dx, dy) in HudLayout.textOutlineOffsets do
+                PixelText.draw spriteBatch pixel cjkAtlas (x + dx) (textY + dy) HudLayout.textScale palette.Outline segment.Label
+                PixelText.draw spriteBatch pixel cjkAtlas (x + labelAdvanced + dx) (textY + dy) HudLayout.textScale palette.Outline segment.Value
+            PixelText.draw spriteBatch pixel cjkAtlas x textY HudLayout.textScale palette.Label segment.Label
             PixelText.draw spriteBatch pixel cjkAtlas (x + labelAdvanced) textY HudLayout.textScale palette.Value segment.Value
         spriteBatch.End()
 
diff --git a/src/LivingVillage.Desktop/HudLayout.fs b/src/LivingVillage.Desktop/HudLayout.fs
index d943cec..f3e4c12 100644
--- a/src/LivingVillage.Desktop/HudLayout.fs
+++ b/src/LivingVillage.Desktop/HudLayout.fs
@@ -44,14 +44,26 @@ module HudLayout =
                 (paddingX, [])
         List.rev placed
 
+    /// P26：常驻片段文本的 1px 描边偏移（上/下/左/右），保证白天/夜景下都可读。
+    let textOutlineOffsets : (int * int) list = [ (-1, 0); (1, 0); (0, -1); (0, 1) ]
+
+    /// P26：常驻片段的半透明底色药丸，贴合文字高度并在左右各留 6px；纯函数便于回归。
+    let segmentBackdrop (x: int) (width: int) : Microsoft.Xna.Framework.Rectangle =
+        let height = 8 * textScale + 10
+        let y = (barHeight - height) / 2
+        Microsoft.Xna.Framework.Rectangle(x - 6, y, width + 12, height)
+
     type Palette =
         { BarTop: Color
           BarBottom: Color
           Accent: Color
           Label: Color
-          Value: Color }
+          Value: Color
+          SegmentBackdrop: Color
+          Outline: Color }
 
     /// 白天暖色 / 夜晚（冬夜）冷色微调；均为半透明渐变窄条，无大黑块。
+    /// 每个常驻片段再叠一层半透明底色 + 1px 深色描边，双时段都能读清。
     let palette (mode: M6DayNight) : Palette =
         match mode with
         | Day ->
@@ -59,10 +71,14 @@ module HudLayout =
               BarBottom = Color(22, 34, 40, 200)
               Accent = Color(212, 168, 96)
               Label = Color(206, 220, 208)
-              Value = Color(242, 248, 234) }
+              Value = Color(242, 248, 234)
+              SegmentBackdrop = Color(8, 14, 20, 150)
+              Outline = Color(6, 10, 14, 255) }
         | Night ->
             { BarTop = Color(22, 30, 48, 205)
               BarBottom = Color(13, 19, 33, 205)
               Accent = Color(120, 168, 196)
               Label = Color(176, 196, 214)
-              Value = Color(228, 238, 246) }
+              Value = Color(228, 238, 246)
+              SegmentBackdrop = Color(4, 8, 16, 160)
+              Outline = Color(3, 6, 12, 255) }