diff --git a/src/app/mod.rs b/src/app/mod.rs
index e6b9a116..45926639 100644
--- a/src/app/mod.rs
+++ b/src/app/mod.rs
@@ -3777,6 +3777,28 @@ impl OpenCADStudio {
     fn boot_web() -> (Self, Task<Message>) {
         #[cfg_attr(target_arch = "wasm32", allow(unused_mut))]
         let mut s = Self::new();
+
+        // CMMS embedding (not upstream): follow the CMMS user's light/dark
+        // theme. window.CAD_EDITOR_CONFIG.dark is set by cad-edit.php from
+        // theme_is_dark(). Overrides the persisted config theme that
+        // Self::new()'s apply_config() just set - the embedded editor always
+        // opens straight into a file and should match the CMMS chrome, not
+        // whatever theme was last picked in a standalone session. Standalone
+        // use (no config) leaves everything untouched.
+        if let Some(cfg) = crate::sys::cmms_config() {
+            let iced_theme = if cfg.dark {
+                iced::Theme::Oxocarbon
+            } else {
+                iced::Theme::Light
+            };
+            s.ui_theme = config::UiThemeConfig {
+                name: iced_theme.to_string(),
+                palette: config::UiThemePalette::from_iced(iced_theme.seed()),
+            };
+            s.active_theme = iced_theme;
+            s.theme_color_inputs = s.ui_theme.palette.hex_values();
+        }
+
         let focus = s.focus_cmd_input();
         let primary_font = crate::scene::text::web_font::preload_language(
             &crate::i18n::active_language_tag(),
diff --git a/src/sys.rs b/src/sys.rs
index c9ada909..4357f2e3 100644
--- a/src/sys.rs
+++ b/src/sys.rs
@@ -320,6 +320,10 @@ pub struct CmmsConfig {
     pub load_url: Option<String>,
     pub attachment_id: Option<String>,
     pub original_name: Option<String>,
+    // Whether the CMMS user's active theme reads as dark (theme_is_dark() in
+    // cad-edit.php). Drives the editor's iced theme at boot so it opens
+    // light or dark to match. Absent (standalone) -> false -> unchanged.
+    pub dark: bool,
 }
 
 #[cfg(target_arch = "wasm32")]
@@ -336,6 +340,12 @@ pub fn cmms_config() -> Option<CmmsConfig> {
             .ok()?
             .as_string()
     };
+    let get_bool = |key: &str| -> bool {
+        js_sys::Reflect::get(&config, &JsValue::from_str(key))
+            .ok()
+            .and_then(|v| v.as_bool())
+            .unwrap_or(false)
+    };
     Some(CmmsConfig {
         save_url: get_str("saveUrl")?,
         job_id: get_str("jobId")?,
@@ -343,6 +353,7 @@ pub fn cmms_config() -> Option<CmmsConfig> {
         load_url: get_str("loadUrl"),
         attachment_id: get_str("attachmentId"),
         original_name: get_str("originalName"),
+        dark: get_bool("dark"),
     })
 }