diff --git a/themes/d0340dd5-0a26-4e25-be47-23d9d86785a0/chrome.css b/themes/d0340dd5-0a26-4e25-be47-23d9d86785a0/chrome.css
new file mode 100644
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--- /dev/null
+++ b/themes/d0340dd5-0a26-4e25-be47-23d9d86785a0/chrome.css
@@ -0,0 +1,17 @@
+
+:root[inFullscreen] {
+  #zen-main-app-wrapper {
+    /*
+    override
+    background: var(--zen-themed-toolbar-bg-transparent)
+    */
+    background: var(--zen-branding-bg)!important;
+
+/* keep grey-out setting intact */
+    @media (-moz-pref("zen.view.grey-out-inactive-windows")) {
+      &:-moz-window-inactive {
+        background: InactiveCaption!important;;
+      }
+    }
+  }
+}
diff --git a/themes/d0340dd5-0a26-4e25-be47-23d9d86785a0/image.png b/themes/d0340dd5-0a26-4e25-be47-23d9d86785a0/image.png
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index 00000000..21a444d0
Binary files /dev/null and b/themes/d0340dd5-0a26-4e25-be47-23d9d86785a0/image.png differ
diff --git a/themes/d0340dd5-0a26-4e25-be47-23d9d86785a0/readme.md b/themes/d0340dd5-0a26-4e25-be47-23d9d86785a0/readme.md
new file mode 100644
index 00000000..8d2b3ce8
--- /dev/null
+++ b/themes/d0340dd5-0a26-4e25-be47-23d9d86785a0/readme.md
@@ -0,0 +1,16 @@
+
+# Solid Fullscreen
+
+This mod prevents the wallpaper from bleeding through in fullscreen mode.
+
+<details>
+<summary>before</summary>
+
+![image](https://raw.githubusercontent.com/blu14x/zen/main/solidFullscreen/img/before.png)
+</details>
+
+<details open>
+<summary>after</summary>
+
+![image](https://raw.githubusercontent.com/blu14x/zen/main/solidFullscreen/img/after.png)
+</details>
diff --git a/themes/d0340dd5-0a26-4e25-be47-23d9d86785a0/theme.json b/themes/d0340dd5-0a26-4e25-be47-23d9d86785a0/theme.json
new file mode 100644
index 00000000..3574ec70
--- /dev/null
+++ b/themes/d0340dd5-0a26-4e25-be47-23d9d86785a0/theme.json
@@ -0,0 +1,14 @@
+{
+    "id": "d0340dd5-0a26-4e25-be47-23d9d86785a0",
+    "name": "Solid Fullscreen",
+    "description": "This mod prevents the wallpaper from bleeding through in fullscreen mode.",
+    "homepage": "https://github.com/blu14x/zen/tree/main/solidFullscreen",
+    "style": "https://raw.githubusercontent.com/zen-browser/theme-store/main/themes/d0340dd5-0a26-4e25-be47-23d9d86785a0/chrome.css",
+    "readme": "https://raw.githubusercontent.com/zen-browser/theme-store/main/themes/d0340dd5-0a26-4e25-be47-23d9d86785a0/readme.md",
+    "image": "https://raw.githubusercontent.com/zen-browser/theme-store/main/themes/d0340dd5-0a26-4e25-be47-23d9d86785a0/image.png",
+    "author": "blu14x",
+    "version": "1.0.0",
+    "tags": [],
+    "createdAt": "2026-02-21",
+    "updatedAt": "2026-02-21"
+}
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