diff --git a/pagetop-bootsier/src/lib.rs b/pagetop-bootsier/src/lib.rs
index b80e96c1..e96fbe87 100644
--- a/pagetop-bootsier/src/lib.rs
+++ b/pagetop-bootsier/src/lib.rs
@@ -131,18 +131,24 @@ impl ThemeTrait for Bootsier {
             }
             COMPONENT_BASE_HEADING => {
                 let h = component_as_mut::<Heading>(component);
-                let original = h.display().to_string();
-                h.alter_classes(
-                    ClassesOp::SetDefault,
-                    match h.display() {
-                        HeadingDisplay::ExtraLarge => "display-1",
-                        HeadingDisplay::XxLarge => "display-2",
-                        HeadingDisplay::XLarge => "display-3",
-                        HeadingDisplay::Large => "display-4",
-                        HeadingDisplay::Medium => "display-5",
-                        _ => original.as_str(),
-                    },
-                );
+                match h.display() {
+                    HeadingDisplay::ExtraLarge => {
+                        h.alter_classes(ClassesOp::Replace(h.display().to_string()), "display-1");
+                    }
+                    HeadingDisplay::XxLarge => {
+                        h.alter_classes(ClassesOp::Replace(h.display().to_string()), "display-2");
+                    }
+                    HeadingDisplay::XLarge => {
+                        h.alter_classes(ClassesOp::Replace(h.display().to_string()), "display-3");
+                    }
+                    HeadingDisplay::Large => {
+                        h.alter_classes(ClassesOp::Replace(h.display().to_string()), "display-4");
+                    }
+                    HeadingDisplay::Medium => {
+                        h.alter_classes(ClassesOp::Replace(h.display().to_string()), "display-5");
+                    }
+                    _ => {}
+                };
             }
             COMPONENT_BASE_PARAGRAPH => {
                 let p = component_as_mut::<Paragraph>(component);
diff --git a/pagetop/src/base/component/block.rs b/pagetop/src/base/component/block.rs
index cff0f744..a56a4af2 100644
--- a/pagetop/src/base/component/block.rs
+++ b/pagetop/src/base/component/block.rs
@@ -18,7 +18,7 @@ pub struct Block {
 
 impl ComponentTrait for Block {
     fn new() -> Self {
-        Block::default().with_classes(ClassesOp::SetDefault, "block")
+        Block::default().with_classes(ClassesOp::AddDefault, "block")
     }
 
     fn handle(&self) -> Handle {
diff --git a/pagetop/src/base/component/flex/container.rs b/pagetop/src/base/component/flex/container.rs
index da37b150..ed71e85f 100644
--- a/pagetop/src/base/component/flex/container.rs
+++ b/pagetop/src/base/component/flex/container.rs
@@ -22,7 +22,7 @@ pub struct Container {
 impl ComponentTrait for Container {
     fn new() -> Self {
         Container::default()
-            .with_classes(ClassesOp::SetDefault, flex::Direction::Default.to_string())
+            .with_classes(ClassesOp::AddDefault, flex::Direction::Default.to_string())
     }
 
     fn handle(&self) -> Handle {
diff --git a/pagetop/src/base/component/flex/item.rs b/pagetop/src/base/component/flex/item.rs
index 1b44f26f..d7f1f907 100644
--- a/pagetop/src/base/component/flex/item.rs
+++ b/pagetop/src/base/component/flex/item.rs
@@ -23,8 +23,8 @@ pub struct Item {
 impl ComponentTrait for Item {
     fn new() -> Self {
         Item::default()
-            .with_item_classes(ClassesOp::SetDefault, "pt-flex__item")
-            .with_inner_classes(ClassesOp::SetDefault, "pt-flex__item-inner")
+            .with_item_classes(ClassesOp::AddDefault, "pt-flex__item")
+            .with_inner_classes(ClassesOp::AddDefault, "pt-flex__item-inner")
     }
 
     fn handle(&self) -> Handle {
diff --git a/pagetop/src/base/component/form/button.rs b/pagetop/src/base/component/form/button.rs
index 1fce9dc9..1e111459 100644
--- a/pagetop/src/base/component/form/button.rs
+++ b/pagetop/src/base/component/form/button.rs
@@ -26,7 +26,7 @@ pub struct Button {
 
 impl ComponentTrait for Button {
     fn new() -> Self {
-        Button::default().with_classes(ClassesOp::SetDefault, "btn btn-primary form-button")
+        Button::default().with_classes(ClassesOp::AddDefault, "btn btn-primary form-button")
     }
 
     fn handle(&self) -> Handle {
diff --git a/pagetop/src/base/component/form/date.rs b/pagetop/src/base/component/form/date.rs
index 22190bab..af319873 100644
--- a/pagetop/src/base/component/form/date.rs
+++ b/pagetop/src/base/component/form/date.rs
@@ -23,7 +23,7 @@ pub struct Date {
 
 impl ComponentTrait for Date {
     fn new() -> Self {
-        Date::default().with_classes(ClassesOp::SetDefault, "form-item form-type-date")
+        Date::default().with_classes(ClassesOp::AddDefault, "form-item form-type-date")
     }
 
     fn handle(&self) -> Handle {
diff --git a/pagetop/src/base/component/form/form_main.rs b/pagetop/src/base/component/form/form_main.rs
index a2bed394..70261ca2 100644
--- a/pagetop/src/base/component/form/form_main.rs
+++ b/pagetop/src/base/component/form/form_main.rs
@@ -28,7 +28,7 @@ pub struct Form {
 impl ComponentTrait for Form {
     fn new() -> Self {
         Form::default()
-            .with_classes(ClassesOp::SetDefault, "form")
+            .with_classes(ClassesOp::AddDefault, "form")
             .with_charset("UTF-8")
     }
 
diff --git a/pagetop/src/base/component/form/input.rs b/pagetop/src/base/component/form/input.rs
index 74a92497..55340a46 100644
--- a/pagetop/src/base/component/form/input.rs
+++ b/pagetop/src/base/component/form/input.rs
@@ -39,7 +39,7 @@ pub struct Input {
 impl ComponentTrait for Input {
     fn new() -> Self {
         Input::default()
-            .with_classes(ClassesOp::SetDefault, "form-item form-type-textfield")
+            .with_classes(ClassesOp::AddDefault, "form-item form-type-textfield")
             .with_size(Some(60))
             .with_maxlength(Some(128))
     }
diff --git a/pagetop/src/base/component/icon.rs b/pagetop/src/base/component/icon.rs
index ecc7a859..b35287e3 100644
--- a/pagetop/src/base/component/icon.rs
+++ b/pagetop/src/base/component/icon.rs
@@ -14,7 +14,7 @@ pub struct Icon {
 
 impl ComponentTrait for Icon {
     fn new() -> Self {
-        Icon::default().with_classes(ClassesOp::SetDefault, "bi-question-circle-fill")
+        Icon::default().with_icon_name("question-circle-fill")
     }
 
     fn handle(&self) -> Handle {
@@ -75,7 +75,10 @@ impl Icon {
 
     #[fn_builder]
     pub fn alter_icon_name(&mut self, name: &str) -> &mut Self {
-        self.alter_classes(ClassesOp::SetDefault, concat_string!("bi-", name));
+        self.classes.alter_value(
+            ClassesOp::Replace(concat_string!("bi-", self.icon_name)),
+            concat_string!("bi-", name),
+        );
         self.icon_name = name.to_owned();
         self
     }
diff --git a/pagetop/src/base/component/image.rs b/pagetop/src/base/component/image.rs
index cf67191b..181cda6a 100644
--- a/pagetop/src/base/component/image.rs
+++ b/pagetop/src/base/component/image.rs
@@ -28,7 +28,7 @@ pub struct Image {
 
 impl ComponentTrait for Image {
     fn new() -> Self {
-        Image::default().with_classes(ClassesOp::SetDefault, IMG_FLUID)
+        Image::default().with_classes(ClassesOp::AddDefault, IMG_FLUID)
     }
 
     fn handle(&self) -> Handle {
@@ -70,19 +70,19 @@ impl Image {
     pub fn with(source: &str) -> Self {
         Image::default()
             .with_source(source)
-            .with_classes(ClassesOp::SetDefault, IMG_FLUID)
+            .with_classes(ClassesOp::AddDefault, IMG_FLUID)
     }
 
     pub fn fixed(source: &str) -> Self {
         Image::default()
             .with_source(source)
-            .with_classes(ClassesOp::SetDefault, IMG_FIXED)
+            .with_classes(ClassesOp::AddDefault, IMG_FIXED)
     }
 
     pub fn pagetop() -> Self {
         Image::default()
             .with_source("/base/pagetop-logo.svg")
-            .with_classes(ClassesOp::SetDefault, IMG_FIXED)
+            .with_classes(ClassesOp::AddDefault, IMG_FIXED)
             .with_size(ImageSize::Size(64, 64))
     }
 
diff --git a/pagetop/src/base/component/wrapper.rs b/pagetop/src/base/component/wrapper.rs
index 75061dc7..8480e683 100644
--- a/pagetop/src/base/component/wrapper.rs
+++ b/pagetop/src/base/component/wrapper.rs
@@ -30,8 +30,8 @@ pub struct Wrapper {
 impl ComponentTrait for Wrapper {
     fn new() -> Self {
         Wrapper::default()
-            .with_classes(ClassesOp::SetDefault, "container")
-            .with_inner_classes(ClassesOp::SetDefault, "container")
+            .with_classes(ClassesOp::AddDefault, "container")
+            .with_inner_classes(ClassesOp::AddDefault, "container")
     }
 
     fn handle(&self) -> Handle {
@@ -99,25 +99,33 @@ impl ComponentTrait for Wrapper {
 
 impl Wrapper {
     pub fn header() -> Self {
-        let mut c = Wrapper::new().with_classes(ClassesOp::SetDefault, "header");
+        let mut c = Wrapper::default()
+            .with_classes(ClassesOp::AddDefault, "header")
+            .with_inner_classes(ClassesOp::AddDefault, "container");
         c.wrapper_type = WrapperType::Header;
         c
     }
 
     pub fn footer() -> Self {
-        let mut c = Wrapper::new().with_classes(ClassesOp::SetDefault, "footer");
+        let mut c = Wrapper::default()
+            .with_classes(ClassesOp::AddDefault, "footer")
+            .with_inner_classes(ClassesOp::AddDefault, "container");
         c.wrapper_type = WrapperType::Footer;
         c
     }
 
     pub fn main() -> Self {
-        let mut c = Wrapper::new().with_classes(ClassesOp::SetDefault, "main");
+        let mut c = Wrapper::default()
+            .with_classes(ClassesOp::AddDefault, "main")
+            .with_inner_classes(ClassesOp::AddDefault, "container");
         c.wrapper_type = WrapperType::Main;
         c
     }
 
     pub fn section() -> Self {
-        let mut c = Wrapper::new().with_classes(ClassesOp::SetDefault, "section");
+        let mut c = Wrapper::default()
+            .with_classes(ClassesOp::AddDefault, "section")
+            .with_inner_classes(ClassesOp::AddDefault, "container");
         c.wrapper_type = WrapperType::Section;
         c
     }
diff --git a/pagetop/src/html/opt_classes.rs b/pagetop/src/html/opt_classes.rs
index a3f0444e..0df33e4e 100644
--- a/pagetop/src/html/opt_classes.rs
+++ b/pagetop/src/html/opt_classes.rs
@@ -3,9 +3,9 @@
 //! This *helper* differentiates between default classes (generally associated with styles provided
 //! by the theme) and user classes (for customizing components based on application styles).
 //!
-//! Default classes can be added using [SetDefault] and [AddDefault], while user classes can be
-//! added using [Add]. Operations to [Remove], [Replace] or [ReplaceIfExists] a class, as well as
-//! to [Reset] user classes, are also provided.
+//! Default classes can be added using [AddDefault], while user classes can be added using [Add].
+//! Operations to [Remove], [Replace] or [ReplaceIfExists] a class, as well as to [Reset] user
+//! classes, are also provided.
 //!
 //! Although the order of the classes is irrelevant (<https://stackoverflow.com/a/1321712>), default
 //! classes will be presented before user classes and duplicate classes will not be allowed.
@@ -13,7 +13,6 @@
 use crate::fn_builder;
 
 pub enum ClassesOp {
-    SetDefault,
     AddDefault,
     Add,
     Remove,
@@ -51,10 +50,6 @@ impl OptionClasses {
         let classes: Vec<&str> = classes.split_ascii_whitespace().collect();
 
         match op {
-            ClassesOp::SetDefault => {
-                self.0.retain(|(_, t)| t.ne(&ClassType::Default));
-                self.add(&classes, 0, ClassType::Default);
-            }
             ClassesOp::AddDefault => {
                 let pos = match self.0.iter().position(|(_, t)| t.eq(&ClassType::User)) {
                     Some(pos) => pos,