refactor(calc-02): simplify calculator layout structure

Move the display and button panels into a single wrapper and rely on
viewport-height sizing with hidden page overflow to keep the calculator
contained. Also trim redundant panel-specific layout rules and styling.

samples/calc-02/index.css

@@ -32,6 +32,7 @@
 html, body {
 	margin: 0;
 	min-height: 100%;
+	overflow-y: hidden;
 }
 
 body {
@@ -52,62 +53,22 @@ body {
 .calculator {
 	width: 100%;
 	max-width: 460px;
-	height: 100%;
-	max-height: 100%;
-	display: grid;
+	height: 100vh;
+	max-height: 100vh;
 	padding: 8px;
 	border-radius: 8px;
 	background: var(--panel);
 	box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.08);
-	grid-template-columns: 1fr;
-	grid-template-rows: auto auto auto auto auto;
-	gap: 6px;
 	justify-content: stretch;
 	align-content: start;
 	overflow-y: auto;
-}
-
-.calculator > .display-block {
-	grid-row: 1;
-}
-
-.calculator > .display-buttons-panel {
-	grid-row: 2;
-}
-
-.calculator > .keypad-panel {
-	grid-row: 3;
-}
-
-.calculator > .functions-panel {
-	grid-row: 4;
-}
-
-.calculator > .trigo-panel {
-	grid-row: 5;
-}
-
-.display-buttons-panel,
-.keypad-panel,
-.functions-panel,
-.trigo-panel {
-	align-self: start;
-	justify-self: stretch;
-}
-
-.keypad-panel,
-.functions-panel,
-.trigo-panel {
-	overflow: auto;
-	min-height: 0;
-}
-
-.calculator > .trigo-panel {
-	margin-top: 0;
+	scrollbar-width: thin;
+	scrollbar-color: rgba(46, 105, 135, 1);
 }
 
 .display-block,
 .display-panel,
+.display-buttons-panel,
 .keypad-panel,
 .functions-panel,
 .trigo-panel {
@@ -117,13 +78,6 @@ body {
 	box-shadow: none;
 }
 
-.display-buttons-panel {
-	border-radius: 8px;
-	border: 1px solid rgba(255, 255, 255, 0.06);
-	background: rgba(6, 10, 16, 0.16);
-	box-shadow: none;
-}
-
 .display-block {
 	display: grid;
 	gap: 0;