3 files changed, 15 insertions, 0 deletions
diff --git a/include/cru/ui/style/StyleRule.h b/include/cru/ui/style/StyleRule.h
index fc37f7c7..27069930 100644
--- a/include/cru/ui/style/StyleRule.h
+++ b/include/cru/ui/style/StyleRule.h
@@ -8,6 +8,10 @@
 #include <vector>
 
 namespace cru::ui::style {
+/**
+ * \brief An immutable style rule contains a condition and a styler.
+ * \remarks This class is immutable and has value semantics.
+ */
 class CRU_UI_API StyleRule : public Object {
  public:
   static ClonablePtr<StyleRule> Create(ClonablePtr<Condition> condition,
diff --git a/include/cru/ui/style/StyleRuleSet.h b/include/cru/ui/style/StyleRuleSet.h
index 348fdd5f..8bf9c9ff 100644
--- a/include/cru/ui/style/StyleRuleSet.h
+++ b/include/cru/ui/style/StyleRuleSet.h
@@ -6,6 +6,12 @@
 #include <cstddef>
 
 namespace cru::ui::style {
+/**
+ *  \brief A set of style rules.
+ *  \remarks Note this class is different from other constructs in style. It is
+ * mutable and has reference semantics. Change of it will be notified by
+ * StyleRuleSet::ChangeEvent.
+ */
 class CRU_UI_API StyleRuleSet : public Object {
  public:
   StyleRuleSet() = default;
diff --git a/include/cru/ui/style/Styler.h b/include/cru/ui/style/Styler.h
index f4f66ea0..7df3e138 100644
--- a/include/cru/ui/style/Styler.h
+++ b/include/cru/ui/style/Styler.h
@@ -10,6 +10,11 @@
 #include <vector>
 
 namespace cru::ui::style {
+/**
+ * \brief The base class for all styler implementations.
+ * \remarks Styler should be immutable. And we use cru::ClonablePtr to wrap it
+ * in order to get both polymorphic and value semantics.
+ */
 class CRU_UI_API Styler : public Object {
  public:
   virtual void Apply(controls::Control* control) const = 0;