Optimize some components

- Use binding of this over `document.querySelector` calls
- Use else if over a chained else and if condition

src/atoms/Counter.svelte

@@ -6,12 +6,14 @@
     export let className = null
 
     // Variables
+    let counter
+    const numbers = [...Array(10).keys()]
+
+    // Reactive variables depending on currentIndex
     $: actualIndex = currentIndex + 1
     $: amount = String(actualIndex).length
     $: index = (actualIndex < 10) ? String(actualIndex).padStart(2, '0') : String(actualIndex)
     $: digits = index.split('')
-    let counter
-    const numbers = [...Array(10).keys()]
 
 
     /*