app.js

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

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

    //Sections active class
    allSections.addEventListener('click', (e) => {
        const id = e.target.dataset.id;
        if(id){
            //remove selected from other btns
            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();