Change timezone

I have this script but right now it’s for NL, I tried to change it for Portugal timezone but immediately stops and doesn’t work. At the same time, I want my nav bar to appear as a display “block” but it’s not working, I have my nav with “display: block:” but I’m not seeing any proper effect. So I don’t know what I’m doing wrong, that’s my first proper coding project by the way 🙂

html {
    background: #fffff2;
    /* background: #FCF9E2; */
    color: #3f3e3e;
    font-family: Cambria, Cochin, Georgia, Times, 'Times New Roman', serif;
}

nav {
    position: absolute;
    right: 1rem;
    top: 1rem;
}

nav {
    display: block;
    unicode-bidi: isolate;
    font-size: 22px;
}

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

  * {
    scrollbar-width: none;
}

footer {
    position: fixed;
    bottom: 0;
    z-index: 10;
    width: calc(100vw - 2rem);
    background-color: inherit;
    border-top: var(--border);
    padding: 1rem;
}



p {
    text-align: center;
    padding: 24rem;
    font-size: 50px;
   
  }

  a {
    color:  #3f3e3e;
    text-decoration: none;
}
  
a:hover {
    color:#00A0C6; 
    text-decoration: green wavy underline;
    cursor:pointer;  
}
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Casa Estrela</title>
    <link rel="stylesheet" href="/style.css">
</head>





<body>

    <header>
      
<p>Casa Estrela: is a non-profit organization and self-organised space for artists, theoreticians, researchers, practitioners, and activists. This is an ongoing process of building a place for creation, study, connection and exchange for everyone who wants to expand their own practice. The house is located in the village of Molelos, in Beira alta Portugal, next to Serra do Caramulo. We have been developing projects and receiving people since 2023. To stay with us, there is no need to apply, nor is there any selection. We practice solidarity prices, as accessible as possible. </p>
        <nav>
            <ul class="nobull">
              <li></li>
                    <li><a href="https://www.instagram.com/casaestrela__/" target="”_blank”">↳ instagram</a></li>
                    <li><a href="mailto:[email protected]" target="”_blank”">↳ email</a></li>
                      </ul>
          <nav>
            </nav></nav>


    </header>
<footer>
    <div>

       It is
       <span id="time">14:24:24</span>
       on a
       <span id="day">Monday</span>
       in Molelos (PT) right now
       <span id="activity">and probably the cats are sleeping</span> 


    </div>
</footer>
<script>
    /* ---------------------------- CLOCK ---------------------------- */
    
    var d = new Date();
    var t = d.toLocaleTimeString("nl-NL", {timeZone: "Europe/Amsterdam"});
    
    
    function clock() {
      var d = new Date();
      var t = d.toLocaleTimeString("nl-NL", {timeZone: "Europe/Amsterdam"});
      document.getElementById("time").innerHTML = t;
    }
    
    document.addEventListener("DOMContentLoaded", () => {
        clock();
        setInterval(clock, 1000);
    });
    
    
    /* ---------------------------- DAY OF THE WEEK ---------------------------- */
        const weekday = ["Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday"];
    
        // const d = new Date();
        let day = weekday[d.getDay()];
        document.getElementById("day").innerHTML = day;
    /* ---------------------------- SCHEDULE ---------------------------- */
    
      console.log(t);
    
      let activity;
      if (t < "09:00:00") {
        activity = "";
        link = ""
      }
        else if (t > "10:00:00" && t < "18:00:00" && "Monday, Tuesday, Wednesday, Thursday, Friday".includes(day)) {
      activity = "and Kirsten should be working";
      document.getElementById("circle").style.backgroundColor="#0000ff";
        }
        else if (t > "09:00:00" && t < "10:00:00" && "Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday".includes(day)) {
      activity = "and Kirsten is probably *essaying*";
      document.getElementById("circle").style.backgroundColor="#00ff00";
        }
      
      else {
        activity = "";
        link = ""
      }
      document.getElementById("activity").innerHTML = activity
    
    
    /* ---------------------------- TIME STAMP ---------------------------- */
    function getTimeStamp() {
         var now = new Date();
         return (now.getHours() + ':' + ((now.getMinutes() < 10) ? ("0" + now.getMinutes()) : (now.getMinutes())) + ':' + ((now.getSeconds() < 10) ? ("0" + now
                       .getSeconds()) : (now.getSeconds())));
    }
    
    
      function timeIn() {
          document.getElementById('timeIn').value = getTimeStamp();
      }
      function timeOut() {
          document.getElementById('timeOut').value = getTimeStamp();
      }
    
      function duration() {
        var diff = timeOut - timeIn; //milliseconds interval
        document.getElementById('duration').value = diff;
      }
    
 </script>
 <script>
    /* ---------------------------- DARKMODE ---------------------------- */
    
    let timeofday
    if (t < "07:00:00") {
      document.body.style.backgroundColor="#111";
      document.body.style.color="#fff";
    }
    else if (t < "20:30:00") {
      document.body.style.backgroundColor="inherit";
      document.body.style.color="inherit";
    }
    else {
      document.body.style.backgroundColor="#111";
      document.body.style.color="#fff";
    }
    </script>


    
</body>




</html>