diff --git a/gui/build.rs b/gui/build.rs
index 6c0dfad..d148ca4 100644
--- a/gui/build.rs
+++ b/gui/build.rs
@@ -1,4 +1,14 @@
+use std::env;
+
 fn main() {
-    let config = slint_build::CompilerConfiguration::new().with_style("cosmic-dark".into());
+    let target_arch = env::var("CARGO_CFG_TARGET_ARCH").expect("target arch env");
+    let style = match target_arch.as_str() {
+        // For web, rely on dark mod detection based on browser settings.
+        "wasm32" => "cosmic",
+
+        // For any other target, force dark mode.
+        _ => "cosmic-dark",
+    };
+    let config = slint_build::CompilerConfiguration::new().with_style(style.into());
     slint_build::compile_with_config("ui/app.slint", config).expect("Slint build failed");
 }