diff --git a/src/main.rs b/src/main.rs
index 95e79ef..912299d 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,22 +1,27 @@
 use osui::{
-    elements::grid::{HGrid, VGrid},
-    extensions::{id::IdExtension, tick::TickExtension},
+    elements::{
+        div::Div,
+        grid::{HGrid, VGrid},
+    },
     style::Transform,
     Screen,
 };
 
 fn main() {
     let mut screen = Screen::new();
-    let document = IdExtension::new();
-    screen.extension(document.clone());
-    screen.extension(TickExtension(10));
 
-    let vgrid = VGrid::new(0xff0000, 1);
+    let container = Div::new(0xffff00);
 
-    screen.draw(vgrid.clone()).component(Transform::center());
+    screen
+        .draw(container.clone())
+        .component(Transform::center().dimensions(70, 11));
+
+    let vgrid = VGrid::new(0x0000ff, 1);
+
+    container.draw(screen.draw(vgrid.clone()).component(Transform::center()));
 
     for _ in 1..6 {
-        let row = HGrid::new(0xff0000, 1);
+        let row = HGrid::new(0xff00ff, 1);
 
         vgrid.draw(screen.draw(row.clone()));
 
diff --git a/src/style.rs b/src/style.rs
index 5e3e112..71dd4e4 100644
--- a/src/style.rs
+++ b/src/style.rs
@@ -110,16 +110,30 @@ impl Dimension {
 
 impl Position {
     pub fn use_position(&self, size: u16, parent: u16, m: i32, r: &mut u16) {
-        match self {
-            Self::Center => *r = (parent - size) / 2,
-            Self::Const(n) => *r = *n,
-            Self::End => *r = parent - size,
-        }
+        let base = match self {
+            Self::Center => {
+                if parent < size {
+                    return;
+                }
+                (parent - size) / 2
+            }
+            Self::Const(n) => *n,
+            Self::End => {
+                if parent < size {
+                    return;
+                }
+                parent - size
+            }
+        };
 
-        if m > 0 {
-            *r += m as u16;
+        let adjusted = if m >= 0 {
+            base.checked_add(m as u16)
         } else {
-            *r -= -m as u16;
+            base.checked_sub((-m) as u16)
+        };
+
+        if let Some(val) = adjusted {
+            *r = val;
         }
     }
 }