Remove unwanted padding on lower resolutions

Question

:root {
    --primary-color: #10b929ff;
    --background-light-grey: #696969;
    --background-dark-grey: #2f2f2f;
}

body {
    background: var(--background-light-grey);
    margin: 0;
    font-family: 'Josefin Sans', sans-serif;
}

.navbar {
    background: var(--background-dark-grey);
    padding: 1em;
    font-family: 'Josefin Sans', sans-serif;
    //position: fixed;
    
}   


footer {
    background: #2f2f2f;
}

nav {
    display: none;
    position: fixed;
    z-index: 999;
    width: 66%;
    right: 0;
    top:0;
    background-color: var(--background-dark-grey);
    height: 100%;
    padding: 2em;

    ul.primary-nav {
        margin-top: 5em;
    }
    
    li {
        a{
            color: white;
            text-decoration: none;
            display: block;
            padding: .5em;
            text-align: right;
            font-size: 30px;

            &:hover{
                font-weight: bold;
            }
        }
    }
}

.mobile-menu-exit{
    float: right;
    margin: .5em;
    cursor: pointer;
}



nav.menu-btn {
    display: block;
    
}

.website-logo {
    display: flex;
    place-content: space-between;
}

.mobile-menu{
    cursor: pointer;
    width: 2em;
    //max-width: 10%;
}

@media only screen and (max-width: 400px){
    nav{
        width: 44%;
        padding-right: 30px;
    }
}

@media only screen and (max-width: 768px){
    .mobile-menu{
        cursor: pointer;
        width: 2em;
        max-width: 10%;
    }
    .website-logo {
        display: flex;
        place-content: space-between;
    
        img{
            width: 200px;
        }
    }

    .mobile-menu-exit{
        float: right;
        margin: .5em;
        cursor: pointer;
        max-width: 10%;
    }
}

a {
    color: white;
}

ul {
    list-style-type: none;
    margin: 0;
    padding: 0;
}

section {
    padding: 10em 0em 5em 0em;
}

.hero {
    text-align: center;
    //padding-bottom: 160px;
}

.hero-image{
    background-image: url("https://am3pap006files.storage.live.com/y4pNuJohtpUdzBTZoc4fAQHlLNdeLvEQERim4Rs1KspeWQaKszREazNg4Ljnl7YTmkR6Sgsa4MUN4kB4aAf-vbbEuFnP9EPp2tAExe-dH_9o45qLndBetYu64mzC8r1Ynb8pOgWBAoqfzUL6lgg-Oue0OCqK6PPNliLbVrv6A3Yhuqalg__GtCNUkfzHJbwEuEtMWtpMjsvc_zHKMDeI1jNt5lG7eLxLiR5TluSAml-UuQ/IMG_0560.jpg?psid=1&width=720&height=486");
    background-repeat: no-repeat;
    background-position: center;
    overflow: hidden;
    background-size: cover;
    text-align: center;
    padding-bottom: 160px;
}

.centre-col {

    color: white;

    h1 {
        text-transform: uppercase;
        font-weight: 600;
        font-size: 3em;
        resize: horizontal;
        margin-bottom: 10px;
    }

    h3 {
        font-weight: 200;
        font-size: 1.2em;
        margin-bottom: 20px;
    }

    .primary-cta {

        background: var(--primary-color);
        padding: .6em 1.3em;   
        text-decoration: none;
        border-radius: 5em;
        display: inline-block;
        font-size: 1.5em;
    }
}

.instagram-feed {
    padding-top: 00px;
    padding-bottom: 10px;
    z-index: 0;
}
.eapps-link img {
    display:none !important;
}

.club-vision-values {
    background: var(--background-light-grey);
    z-index: 1;
    top: 40%;
    padding-top: 0px;
    text-align: center;
    color: white;
    margin-left: 2em;
    margin-right: 2em;
    margin-bottom: 10px;
    padding-bottom: 20px;
    margin-top: 10px;
    position: relative;
}

.the-coaches{
    padding: 20px;

   ul{
    max-width: 500px;
    //padding-top: 10px;
    display: gird;
    grid-template-columns: repeat(3, 1fr);
    justify-content: space-between;
    align-items: center;
    padding-left: 20px;
    padding-right: 20px;
    }
}

.coach-list {
    column-count: 2;
    max-width: 500px;
    margin: auto;
}

.card {
    box-shadow: 0 4px 8px 0 rgba(0,0,0,0.2);
    max-width: 800px;
    margin: auto;
    text-align: center;
    background: var(--primary-color);
    color: white;
    margin-bottom: 40px;

    h1 {
        margin: 4px;
        margin-top: 10px;
    }

    p {
        font-size: 18px;
        margin-top: 10px;
        margin-bottom: 10px;
        padding-bottom: 8px;
        //padding-top: 3px;
    }
}

@media only screen and (min-width: 768px){
    .coach-list {
        column-count: 2;
        max-width: 800px;
        margin: auto;
    }
}

@media only screen and (min-width: 1080px){
    .coach-list {
        display: inline;
        max-width: 2600px;
        display: flex;
        justify-content: center;
    }

    .the-coaches{
        padding: 20px;
        padding-bottom: 40px;
        margin: auto;
        ul {
            max-width: 2200px;
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding-left: 40px;
            padding-right: 40px;
        }
    }

    .card {
        margin: 10px;
    }
}

.footer{

    margin:0;
    padding: 0;
    box-sizing: border-box;
}

.footer-container{
    
    max-width: 1670px;
    margin:auto;
}

.footer-col {
    color: white;
    width: 20%;
    padding: 0 35px;
}

.footer-col h4{
    font-size: 18px;
    margin-bottom: 20px;
    position: relative;
}

.about-us {
    line-height: 25px;
}

.footer-col h4::before{
    content: '';
    position: absolute;
    left:0;
    bottom: -10px;
    background-color: var(--primary-color);
    height: 2px;
    box-sizing: border-box;
    width: 50px;
}

.row
{
    display: flex;
    flex-wrap: wrap;   
}

ul{
    list-style: none;
}

.footer{
    padding: 60px;
}

.footer-col .social-links a{
    display: inline-block;
    height: 40px;
    width: 40px;
    background-color: rgba(255,255,255,0.2);
    margin:0 10px 10px 0;
    text-align: center;
    line-height: 40px;
    border-radius: 50%;
    color: #ffffff;
    transition: all 0.5s ease;
}
.footer-col .social-links a:hover{
    color: #24262b;
    background-color: #ffffff;
}

/*responsive*/

@media(max-width: 767px){
    .footer-col{
      width: 50%;
      margin-bottom: 30px;
  }
  }
  @media(max-width: 574px){
    .footer-col{
      width: 100%;
  }
}

 <!DOCTYPE html>
 <html lang="en">
 <head>
     <meta charset="UTF-8">
     <meta http-equiv="X-UA-Compatible" content="IE=edge">
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <title>New Era Boxing</title>
     <link href="https://fonts.googleapis.com/css2?family=Josefin+Sans:wght@400;500;600;700&display=swap" rel="stylesheet">
     <link rel="stylesheet" href="css/main.css">
     <link rel="preconnect" href="https://fonts.googleapis.com">
     <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
     <link rel="stylesheet" type="text/css" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.0.0/css/all.min.css">
 </head>
 <body>
     <div class="navbar">
         <div class="website-logo">
            <img id="logo" class="logo" src="Images/logo.svg" alt="The club logo">

            <img id="mobile-cta" class="mobile-menu" src="images/menu.svg" alt="Open Navigation">
            <nav>
                <img id="mobile-exit" class="mobile-menu-exit" src="images/exit.svg" alt="Exit Navigation">

                <ul class="primary-nav">
                    <li><a href="#">Classes</a></li>
                    <li><a href="#">FAQs</a></li>
                    <li><a href="#">Contact Us</a></li>
                </ul>
                
                
            </nav>
         </div>
     </div>
     
     <section class="hero-image">
        <div class="container">
                <!-- <img src="images/raul.JPG" alt="Raul"> -->
            <div class="centre-col">
                <h1>First-class boxing training<br>
                    for youths and adults alike</h1>
                <h3>We provide a supportive and inclusive training environment</h3>
                <div class="hero-cta">
                    <a href="#" class="primary-cta">View our timetable</a>
                </div>
            </div>
            </div>
        </div>
     </section>

     <section class="instagram-feed">
        <script src="https://apps.elfsight.com/p/platform.js" defer></script>
        <div class="elfsight-app-a2b6cbed-0090-4fd3-9a99-b6ce405f0cbf"></div>     
     </section>

<section class="club-vision-values">
         <div>
             <h2>Our Club</h2>
             <p>New-Era Boxing Club was formed in 2011 by Mark Bebbington and focuses on teaching core values as well as providing first class training for youths and adults alike</p>
         </div>
         <div>
            <h2>Our Vision</h2>
            <p>Our vision is to create opportunities for members through boxing, education and personal development in doing so we will provide a supportive and inclusive training environment.</p>
         </div>
         <div>
            <h2>Our Values</h2>
            <p>New Era Boxing emphasises the core value of Equality, Integrity, Compassion, Resilience and Humility at the heart of the clubs activities.</p>
         </div>
     </section>

     <section class="the-coaches">
            <div class="coach-list">
                <ul class="left">
                    <li>
                        <div class="card">
                            <img src="images/mark.PNG" alt="Mark Bebbington - Lead Coach" style="width:100%">
                            <h1>Mark Bebbington</h1>
                            <p>Lead Coach</p>
                        </div>
                    </li>
                    <li>
                        <div class="card">
                            <img src="images/mark.PNG" alt="Mark Bebbington - Lead Coach" style="width:100%">
                            <h1>Mark Bebbington</h1>
                            <p>Lead Coach</p>
                        </div>
                    </li>
                    <li>
                        <div class="card">
                            <img src="images/mark.PNG" alt="Mark Bebbington - Lead Coach" style="width:100%">
                            <h1>Mark Bebbington</h1>
                            <p>Lead Coach</p>
                        </div>
                    </li>
                    <li>
                        <div class="card">
                            <img src="images/mark.PNG" alt="Mark Bebbington - Lead Coach" style="width:100%">
                            <h1>Mark Bebbington</h1>
                            <p>Lead Coach</p>
                        </div>
                    </li>
            </div>
        </div>
     </section>

     <footer class="footer">
         <div class="footer-container">
             <div class="row">
                 <div class="footer-col">
                     <h4>Phone Us</h4>
                         <ul>
                             <li>07830 085132</li>
                         </ul>
                 </div>
                 <div class="footer-col">
                     <h4>Email Us</h4>
                         <ul>
                             <li class="email">[email protected]</li>
                         </ul>
                 </div>
                 <div class="footer-col">
                    <h4>About Us</h4>
                        <ul>
                            <li class="about-us"><a href="#">
                            FAQs
                            </a></li>
                            <li class="about-us"><a href="#">
                            Club Partners
                            </a></li>
                            <li class="about-us"><a href="#">
                            Timetable
                            </a></li>
                        </ul>
                </div>
                 <div class="footer-col">
                     <h4>Follow Us</h4>
                         <div class="social-links">
                             <a href="#"><i class="fab fa-facebook-f"></i></i></a>
                             <a href="#"><i class="fab fa-instagram"></i></i></a>
                             <a href="#"><i class="fab fa-twitter"></i></i></a>
                             <a href="#"><i class="fab fa-whatsapp"></i></i></a>
                         </div>
                 </div>

             </div>
         </div>

     </footer>

    <script>
     const mobileBtn = document.getElementById('mobile-cta')
              nav = document.querySelector('nav')
              mobileBtnExit = document.getElementById('mobile-exit');

        mobileBtn.addEventListener('click', () => {
            nav.classList.add('menu-btn');
        })

        mobileBtnExit.addEventListener('click', () => {
            nav.classList.remove('menu-btn');
        })
    </script>

 </body>
 </html>    

I am viewing my website in the Developer tools but whenever I try to view it in a mobile resolution below 400px wide it seems to add this unwanted padding to the right side. Sometimes this disappears, but other times it just stays there. Is this a common issue and are there any suggestions on how to fix this please?

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