refactor(samples/calc-02): simplify layout to portrait-only single column

Remove the responsive two-column desktop arrangement and make the calculator stack vertically with a 4-column display button row that preserves alignment. Also align the display buttons with the shared base button styling.

samples/calc-02/index.js

@@ -228,7 +228,6 @@ function execute(name) {
 			} else if (calc.isValidIndex(0)) {
 				calc.remove(0);
 			}
-
 		} else if (name === 'swap') {
 			pushEditingValueIfNeeded();
 			if (calc.isValidIndex(1)) {
@@ -489,12 +488,10 @@ downButton.addEventListener('click', () => {
 	}
 });
 
-
 rightButton.addEventListener('click', () => {
 	execute('swap');
 });
 
-
 window.addEventListener('keydown', handleKeyboard, { capture: true });
 window.addEventListener('load', focusInput);
 window.addEventListener('pageshow', focusInput);