Implemented circular selection

When up from first item, go to last
When down from last item, go to first

items.js

@@ -2,21 +2,14 @@ var currentIndex = 0
 
 function nav(offset) {
 	var items = document.querySelectorAll('.items:not(.disabled)')
-	if (offset === -1) {
-		if (currentIndex <= 0) {
-			return
-		}
-	}
-	else if (offset === 1) {
-		if (currentIndex >= items.length - 1) {
-			return
-		}
-	}
-	else {
-		console.error(`nav called with unknown offset: ${offset}`)
-	}
 
 	currentIndex += offset
+	if (currentIndex < 0) {
+		currentIndex += items.length
+	}
+	if (currentIndex >= items.length) {
+		currentIndex -= items.length
+	}
 	items[currentIndex].focus()
 	items[currentIndex].addEventListener('keydown', handleKeyDown)
 }