Create a JavaScript app that fits entirely in a single .html file that works offline. I will describe the web app later. The idea is to have a web app that can be easily shared by downloading or copying the html file. Ideally this does not require third party packages or dependencies, but if so, include their minified form directly in the .html file. Do not minify the source code of the web app, and ensure there are plentify code comments aimed at experienced developers (not beginners). The web app should work on desktop and mobile. The web app's UI should match the dark mode or light mode setting of the browser. The web app will have a langauge selection dropdown that changes the web app's UI language, but don't do any translation just yet (this will wait until the web app development has finished). The language will be automatically set to the browser's language setting, but default to English if not set. The supported languages will be English, Simplified Chinese, Spanish, Arabic, Indonesian, Portuguese, French, Japanese, Russian, German, Hindi, Bengali, Urdu, Korean, Vietnamese, Turkish, Italian, Dutch, Polish, Thai, Persian, Ukrainian, Czech, Malay, Romanian, Greek, Hebrew, Swedish, Filipino, Tamil, Hungarian, Danish, Finnish, Norwegian Bokmål, Slovak, Bulgarian, Serbian, Croatian, Slovenian, Catalan. Start the language selection dropdown with just English, and put emoji flags next to the language options in the dropdown. Use emoji or data uri to embed any needed images. Prefer SVG images for simple icons. Generate OG tags and metadata. Embed a favico in the html file. If the app works with a significant amount of data, offer import/export features defaulting to JSON, markdown, or other appropriate formats. If the data is an image, offer png, jpg, and webp formats. Vector graphics should import/export as SVG and bitmap formats. Ask me about what should be importable/exportable in this app before beginning. Ensure that this app is accessible, such as having alt tags and high contrast. If appropriate, ask me if the app should have color schemes for its user interface including editable and export/import color scheme features. Use local storage and IndexedDB where appropriate. Put the text "This app works offline, just save the .html file." Ask me design questions before beginning. Here is a description of the web app: