3 simple changes to landing Page for Action Sports Facility

I need a developer to work on the landing page for an action sports facility. The project involves minimal JavaScript, primarily for enabling smooth scrolling and implementing some SPA features.

Key Requirements:
- HTML & CSS coding
- Minimal JavaScript for smooth scrolling and SPA and language selection
- Experience with landing page development
- BEM is a must, I'd like clean css

Please note, the landing page will be a partially SPA, not a fully single-page application. I am expecting smooth scrolling throughout the page, so experience with this type of animation is beneficial.

1- Language selection
ES, spanish as default
As in this link:
https://lokales.com.ar/miofis/miofis/index.php
You can use chatgpt to translate

with the following toogle button in the options menu
https://codepen.io/TorabRamin/pen/mqrBBj

2- Remove loading message
I'd like the page to load as in the file spa.html, first section is shown first as soon as finish loading, and as soon as the section is shown keep loading other sections

3- Dark mode. Slightly change colours black and white so as no browser makes changes, or implement dark mode in order to make the page look nice when samsung browser decides to change to darkmode by default.


Check at:
https://xn--diseosmarii-4db.com/Portafolio/2025/febrero/LokalesSinAnimacion/
No animations, but button in burger ok, correct section links

https://xn--diseosmarii-4db.com/Portafolio/2025/febrero/LokalesV2/
Version with loading message, button sections are ok but don't work


Project is hosted:
https://github.com/homeromagio/landing_lokales

Note: Please make each new correction or feature implemented a new commit to the project

Thanks for considering my project! I look forward to finding the right candidate for this job.