diff --git a/crates/anstyle/src/color.rs b/crates/anstyle/src/color.rs
index b930a020..479921d4 100644
--- a/crates/anstyle/src/color.rs
+++ b/crates/anstyle/src/color.rs
@@ -656,7 +656,7 @@ mod test {
 
     #[test]
     fn print_size_of() {
-        use std::mem::size_of;
+        use core::mem::size_of;
         dbg!(size_of::<Color>());
         dbg!(size_of::<AnsiColor>());
         dbg!(size_of::<Ansi256Color>());
diff --git a/crates/anstyle/src/effect.rs b/crates/anstyle/src/effect.rs
index 507dfc83..4a076d4e 100644
--- a/crates/anstyle/src/effect.rs
+++ b/crates/anstyle/src/effect.rs
@@ -385,7 +385,7 @@ mod test {
 
     #[test]
     fn print_size_of() {
-        use std::mem::size_of;
+        use core::mem::size_of;
         dbg!(size_of::<Effects>());
         dbg!(size_of::<EffectsDisplay>());
     }
diff --git a/crates/anstyle/src/reset.rs b/crates/anstyle/src/reset.rs
index 5a4a5f75..b581e16d 100644
--- a/crates/anstyle/src/reset.rs
+++ b/crates/anstyle/src/reset.rs
@@ -28,7 +28,7 @@ mod test {
 
     #[test]
     fn print_size_of() {
-        use std::mem::size_of;
+        use core::mem::size_of;
         dbg!(size_of::<Reset>());
     }
 
diff --git a/crates/anstyle/src/style.rs b/crates/anstyle/src/style.rs
index cfa80858..7cc2bd57 100644
--- a/crates/anstyle/src/style.rs
+++ b/crates/anstyle/src/style.rs
@@ -431,7 +431,7 @@ impl core::fmt::Display for StyleDisplay {
 #[test]
 #[cfg(feature = "std")]
 fn print_size_of() {
-    use std::mem::size_of;
+    use core::mem::size_of;
     dbg!(size_of::<Style>());
     dbg!(size_of::<StyleDisplay>());
 }