JSFiddle - React, Tailwind, and code Playground

HTML

<nav>
    <ul>
        <li><a href="#section1">Section 1</a></li>
        <li><a href="#section2">Section 2</a></li>
        <li><a href="#section3">Section 3</a></li>
        <li><a href="#section4">Section 4</a></li>
        <li><a href="#section5">Section 5</a></li>
        <li><a href="#section6">Section 6</a></li>
    </ul>
</nav>
<section id="section1">
    <h2>Section 1</h2>
    <p>[...] Text [...]</p>
</section>
<section id="section2">
    <h2>Section 2</h2>
    <p>[...] Text [...]</p>
</section>
<section id="section3">
    <h2>Section 3</h2>
    <p>[...] Text [...]</p>
</section>
<section id="section4">
    <h2>Section 4</h2>
    <p>[...] Text [...]</p>
</section>
<section id="section5">
    <h2>Section 5</h2>
    <p>[...] Text [...]</p>
</section>
<section id="section6">
    <h2>Section 6</h2>
    <p>[...] Text [...]</p>
</section>
<footer>
    Footer
</footer>

CSS

nav { 
    position: fixed;
    top: 0;
    z-index: 3;
    width: 100%;
    height: 200px;
    background: gray; 
}

section {
    border: 1px solid red;
    margin: 10px 0 10px 0;
}

section:first-of-type {
    margin-top: 200px;
}

footer {
    height: 100px;
    background: gray;
}

JavaScript

$(document).ready(function(){
	$('a[href^="#"]').on('click',function (e) {
	    e.preventDefault();

	    var target = this.hash,
	    $target = $(target);

	    $('html, body').stop().animate({
	        'scrollTop': $target.offset().top-200 // - 200px (nav-height)
	    }, 900, 'swing', function () {
	        window.location.hash = target;
	    });
	});
});