Пустое пространство создается в верхней части веб-страницы, когда положение навигационной панели установлено фиксированным

const body = document.body;
let lastScroll = 0;
window.addEventListener('scroll', function() {
    const currentScroll=(window.scrollY);
    if (currentScroll<=0){
        body.classList.remove('scroll-up');
    }
    if (currentScroll>lastScroll && !body.classList.contains('scroll-down')){
        body.classList.remove('scroll-up');
        body.classList.add('scroll-down');
    }
    if (currentScroll<lastScroll && body.classList.contains('scroll-down')){
        body.classList.remove('scroll-down');
        body.classList.add('scroll-up');
    }
    lastScroll=currentScroll;
});

*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
body{
    font-family: 'Poppins', sans-serif;
    background-color: #fff;
    color: #fff;
}
nav{
  background-color: transparent;
  z-index: 1000; /* This will make sure the navbar is always on top of other elements */
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px 100px;
    text-transform: uppercase;
    user-select: none;
    transition: all 300ms ease-in-out;
    position: fixed;
    top:0;
    width:100%
}
nav>a{
    cursor: default;
}
nav li{
    list-style: none;
    display: inline;
}
nav a, .hero-btn{
    color: #fff;
    text-decoration: none;
    padding: 10px 15px;
    transition: 200ms;
}
nav a:hover{
    color: grey;

}
.hero-btn:hover{
  background-color: var(--btn-hvr-color);
}
.logo{
    background-image: url(https://i.imgur.com/EKJALav.png);
    background-size: cover;
    height: 150px;
    width: 200px;
}
main{
    background: url('https://i.imgur.com/uMgayfk.png') no-repeat;
    background-size: cover;
    height:100vh;
    background-attachment: fixed;
}
h1{
    font-size: 70px;
    font-family: "Roboto", sans-serif;
    font-weight: 700;
    font-style: normal;
}
.content{
    margin-top: 50px;
    margin-left: var(--text-margin);
    display: flex;
    flex-direction: column;
    justify-content:flex-start;
    flex-wrap: wrap;
    gap: 15px;
}
.btn{
    width: 150px;
    height: 50px;
    border: none;
    outline: none;
    border-radius: 5px;
    display: flex;
    justify-content: center;
    align-items: center;
    user-select: none;
    cursor: pointer;
}
.hero-btn{
    background-color: var(--primary-color);
    font-family: 'Poppins', sans-serif;
    font-size: 1rem;
    font-weight: 600;
    box-shadow: 2px 2px 5px rgba(0, 0, 0, 0.3);
    transition: 300ms;
}
.highlited-txt{
    color: #F8b122;
}
.content p{
    text-shadow: 1px 1px 3px rgba(0, 0, 0, 0.5);
    font-weight: 400; /* Increase as needed */
    font-size: 1.1em; /* Increase as needed */
    line-height: 1.5em; /* Adjust for readability */
}
  }
  .scroll-down nav{
    transform: translate3d(0, -100%, 0);
  }
  .scroll-up nav a{
    color: black;
    transition: 300ms;
  }
  .scroll-up nav a:hover{
    transition: 300ms;
    color: rgb(101, 98, 98);
  }

<main>
            <nav>
                <a href = "https://www.google.com"><div class = "logo">
                </div></a>
                <ul class = "nav-links">
                    <li><a id = "scroll-link" href = "main">Home</a></li>
                    <li><a id = "scroll-link" href = "#about">About</a></li>
                    <li><a id = "scroll-link" href = "#products">Products</a></li>
                    <li><a id = "scroll-link" href = "#contact">Contact</a></li>
                    <li><a id = "scroll-link" href = "./blog.html">Blog</a></li>
                </ul>
                <!-- <div class = "burger">
                    <div class = "line line1"></div>
                    <div class = "line line2"></div>
                    <div class = "line line3"></div>
                </div> -->
            </nav>
    <div class = "content">
        <h1>Powering Your <span class = "highlited-txt">Future</span></h1>
        <p>Elevate your energy strategy with our cutting-edge solar inverters and lithium batteries, designed <br>to deliver sustainable, reliable power for homes, businesses, and industrial applications.</p>
        <a href = "#" class = "btn hero-btn">Learn More</a>
    </div>
</main>