Update README and theme colors to support Mica with alpha variations

Author: vorlie

README.md

@@ -1,4 +1,4 @@
-# Iota's Notepad
+# Iota's Notepad - Mica
 
 Iota's Notepad is a simple note-taking application built with Electron. It allows you to create, edit, and delete notes with a user-friendly interface.
 
@@ -63,9 +63,13 @@ You can add custom themes to Iota's Notepad by importing a JSON file with the th
     {
         "customThemeName": {
             "--color-bg-dark": "#yourColor",
+            "--color-bg-dark-alpha": "#yourColorWithAlpha",
             "--color-bg-darker": "#yourColor",
+            "--color-bg-darker-alpha": "#yourColorWithAlpha",
             "--color-bg-medium": "#yourColor",
+            "--color-bg-medium-alpha": "#yourColorWithAlpha",
             "--color-bg-light": "#yourColor",
+            "--color-bg-light-alpha": "#yourColorWithAlpha",
             "--color-border": "#yourColor",
             "--color-text": "#yourColor",
             "--color-placeholder": "#yourColor",

src/script.js

@@ -9,9 +9,13 @@ const chromeVersion = window.API.versions.chrome();
 const defaultThemes = {
     mocha: {
         '--color-bg-dark': '#1e1e2e',
+        '--color-bg-dark-alpha': '#1e1e2e70',
         '--color-bg-darker': '#11111b',
+        '--color-bg-darker-alpha': '#11111b70',
         '--color-bg-medium': '#313244',
+        '--color-bg-medium-alpha': '#31324470',
         '--color-bg-light': '#45475a',
+        '--color-bg-light-alpha': '#45475a70',
         '--color-border': '#6c7086',
         '--color-text': '#cdd6f4',
         '--color-placeholder': '#a6adc8',
@@ -27,9 +31,13 @@ const defaultThemes = {
     },
     macchiato: {
         '--color-bg-dark': '#24273a',
+        '--color-bg-dark-alpha': '#24273a70',
         '--color-bg-darker': '#181926',
+        '--color-bg-darker-alpha': '#18192670',
         '--color-bg-medium': '#1e2030',
+        '--color-bg-medium-alpha': '#1e203070',
         '--color-bg-light': '#363a4f',
+        '--color-bg-light-alpha': '#363a4f70',
         '--color-border': '#494d64',
         '--color-text': '#cad3f5',
         '--color-placeholder': '#a5adcb',
@@ -45,9 +53,13 @@ const defaultThemes = {
     },
     frappe: {
         '--color-bg-dark': '#303446',
+        '--color-bg-dark-alpha': '#30344670',
         '--color-bg-darker': '#232634',
+        '--color-bg-darker-alpha': '#23263470',
         '--color-bg-medium': '#292c3c',
+        '--color-bg-medium-alpha': '#292c3c70',
         '--color-bg-light': '#414559',
+        '--color-bg-light-alpha': '#41455970',
         '--color-border': '#51576d',
         '--color-text': '#c6d0f5',
         '--color-placeholder': '#a5adcb',