app.js

const sections = document.querySelectorAll('.section');
const sectBtns = document.querySelectorAll('.controls');
const sectBtn = document.querySelectorAll('.control');
const allSections = document.querySelector('.main-content');

function PageTransitions(){

    // Active button class activation on click
    for(let i = 0; i < sectBtn.length; i++){
        sectBtn[i].addEventListener('click', function(){
            let currentBtn = document.querySelectorAll('.active-btn');
            currentBtn[0].className = currentBtn[0].className.replace('active-btn', '')
            this.className += ' active-btn'
        })
    }

    // Active section activation on click
    allSections.addEventListener('click', (e) => {
        const id = e.target.dataset.id;
        if (id){
            // Remove the selected button from other buttons
            sectBtns.forEach((btn) => {
                btn.classList.remove('active')
            })
            e.target.classList.add('active')

            // Hide other sections
            sections.forEach((section) => {
                section.classList.remove('active')
            })

            const element = document.getElementById(id);
            element.classList.add('active');
        }
    })
}

PageTransitions();