merged previous stuffs on master

crates/theme/src/platform_kind.rs

@@ -0,0 +1,33 @@
+#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Clone, Copy)]
+pub enum PlatformKind {
+    Mac,
+    Linux,
+    Windows,
+}
+
+impl PlatformKind {
+    pub const fn platform() -> Self {
+        if cfg!(any(target_os = "linux", target_os = "freebsd")) {
+            Self::Linux
+        } else if cfg!(target_os = "windows") {
+            Self::Windows
+        } else {
+            Self::Mac
+        }
+    }
+
+    #[allow(dead_code)]
+    pub fn is_linux(&self) -> bool {
+        matches!(self, Self::Linux)
+    }
+
+    #[allow(dead_code)]
+    pub fn is_windows(&self) -> bool {
+        matches!(self, Self::Windows)
+    }
+
+    #[allow(dead_code)]
+    pub fn is_mac(&self) -> bool {
+        matches!(self, Self::Mac)
+    }
+}