diff --git a/Cargo.toml b/Cargo.toml
index 9886607..68d059a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -3,10 +3,26 @@ name = "minesweeper6d"
 version = "0.1.2"
 
 [dependencies]
-getrandom = { version = "0.2", features = ["js"] }
 eframe = "0.23"
 hhmmss = "0.1"
 itertools = "0.11"
 rand = "0.8"
 rand_chacha = "0.3"
 toml = "0.8"
+
+# native:
+[target.'cfg(not(target_arch = "wasm32"))'.dependencies]
+env_logger = "0.10"
+
+# web:
+[target.'cfg(target_arch = "wasm32")'.dependencies]
+wasm-bindgen-futures = "0.4"
+
+[profile.release]
+opt-level = 2 # fast and small wasm
+
+# Optimize all dependencies even in debug builds:
+[profile.dev.package."*"]
+opt-level = 2
+
+[patch.crates-io]