Leaflet.js not showing properly

Some reason, leaflet.js is not displaying. I’m completely stumped.

I just want the map to show at full width and I have tried eliminating each file included but non seem to make it work.

any other help toward my code would be amazing as I’m purely learning as I go.

Thank you very much in advance.

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Park Finder</title>
  <link rel="stylesheet" href="https://unpkg.com/leaflet/dist/leaflet.css" />
  <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/css/bootstrap.min.css">
  <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-icons/1.5.0/font/bootstrap-icons.min.css">
  <style>
    body { height: 100vh; display: flex; flex-direction: column; }
    .navbar { background-color: #333; color: white; }
    .suggestions { position: absolute; top: 100%; left: 0; width: 100%; border-radius: 8px; background: white; box-shadow: 0 0 10px rgba(0, 0, 0, 0.1); z-index: 1000; max-height: 200px; overflow-y: auto; margin-top: 8px; }
    .suggestion-item { padding: 10px; cursor: pointer; border-bottom: 1px solid #ddd; }
    .suggestion-item:hover { background: #ff5722; color: white; }
    #map { flex: 1; width: 100%; display: block; height: 100%; }
    .nearby-parks { padding: 10px; background: #f8f8f8; border-top: 1px solid #ccc; height: 200px; overflow-y: auto; }
    .nearby-park { padding: 10px; cursor: pointer; border-bottom: 1px solid #ddd; }
    .nearby-park:hover { background: #007bff; color: white; }
  </style>
</head>
<body>
  <nav class="navbar navbar-expand-lg navbar-dark">
    <div class="container-fluid">
      <span class="navbar-brand">Park Finder</span>
      <div class="search-container ml-auto d-flex">
        <div class="search-bar position-relative">
          <input type="text" id="parkSearch" class="form-control" placeholder="Search for parks...">
          <div class="suggestions" id="suggestions"></div>
        </div>
        <button class="btn btn-primary ml-2" onclick="centerMap()">
          <i class="bi bi-geo-alt"></i> My Location
        </button>
      </div>
    </div>
  </nav>
  <div id="map"></div>
  <div class="nearby-parks container mt-3">
    <h3>Nearby Parks</h3>
    <div id="nearbyParks"></div>
  </div>

  <script src="https://code.jquery.com/jquery-3.5.1.slim.min.js" crossorigin="anonymous"></script>
  <script src="https://cdn.jsdelivr.net/npm/@popperjs/[email protected]/dist/umd/popper.min.js" crossorigin="anonymous"></script>
  <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/js/bootstrap.min.js" crossorigin="anonymous"></script>
  <script src="https://unpkg.com/leaflet/dist/leaflet.js"></script>
  <script>
  document.addEventListener('DOMContentLoaded', () => {
  let parksData = [], userLocation = { lat: null, lon: null };
  var map = L.map('map');

  function centerMap() {
    if (navigator.geolocation) {
      navigator.geolocation.getCurrentPosition(function(position) {
        userLocation.lat = position.coords.latitude;
        userLocation.lon = position.coords.longitude;
        map.setView([userLocation.lat, userLocation.lon], 13);
        showNearbyParks();
      }, function(error) {
        console.error("Geolocation failed: " + error.message);
        alert("Geolocation is not supported by your browser or permission denied.");
      });
    } else {
      alert('Geolocation is not supported by your browser.');
    }
  }

  centerMap();

  fetch('fetch.php')
    .then(response => response.ok ? response.json() : Promise.reject('Network response was not ok'))
    .then(data => {
      parksData = data;
      parksData.forEach(park => {
        L.marker([park.latitude, park.longitude]).addTo(map)
          .bindPopup(`<b>${park.name}</b><br>${park.amenities}`);
      });
      document.querySelector('#parkSearch').addEventListener('input', function(e) {
        let query = e.target.value.toLowerCase();
        if (query) {
          let suggestions = parksData.filter(park => park.name.toLowerCase().includes(query));
          suggestions.sort((a, b) => getDistance(userLocation.lat, userLocation.lon, a.latitude, a.longitude) - getDistance(userLocation.lat, userLocation.lon, b.latitude, b.longitude));
          updateSuggestions(suggestions);
        } else {
          document.getElementById('suggestions').innerHTML = '';
        }
      });
      document.querySelector('#parkSearch').addEventListener('change', function(e) {
        let selectedPark = parksData.find(park => park.name.toLowerCase() === e.target.value.toLowerCase());
        if (selectedPark) {
          map.setView([selectedPark.latitude, selectedPark.longitude], 15);
          L.marker([selectedPark.latitude, selectedPark.longitude]).addTo(map)
            .bindPopup(`<b>${selectedPark.name}</b><br>${selectedPark.amenities}`).openPopup();
          document.getElementById('suggestions').innerHTML = '';
        }
      });
      showNearbyParks();
    })
    .catch(error => {
      console.error('Fetching park data failed:', error);
      alert('Failed to fetch park data. Please try again later.');
    });

  function updateSuggestions(parks) {
    let suggestionsContainer = document.getElementById('suggestions');
    suggestionsContainer.innerHTML = '';
    parks.forEach(park => {
      let suggestionItem = document.createElement('div');
      suggestionItem.textContent = park.name;
      suggestionItem.classList.add('suggestion-item');
      suggestionItem.addEventListener('click', () => {
        document.querySelector('#parkSearch').value = park.name;
        map.setView([park.latitude, park.longitude], 15);
        L.marker([park.latitude, park.longitude]).addTo(map)
          .bindPopup(`<b>${park.name}</b><br>${park.amenities}`).openPopup();
        suggestionsContainer.innerHTML = '';
      });
      suggestionsContainer.appendChild(suggestionItem);
    });
  }

  function showNearbyParks() {
    let nearbyParksContainer = document.getElementById('nearbyParks');
    nearbyParksContainer.innerHTML = '';
    let nearbyParks = parksData.filter(park => getDistance(userLocation.lat, userLocation.lon, park.latitude, park.longitude) <= 5);
    nearbyParks.sort((a, b) => getDistance(userLocation.lat, userLocation.lon, a.latitude, a.longitude) - getDistance(userLocation.lat, userLocation.lon, b.latitude, b.longitude));
    nearbyParks.forEach(park => {
      let nearbyParkItem = document.createElement('div');
      nearbyParkItem.textContent = `${park.name} (${getDistance(userLocation.lat, userLocation.lon, park.latitude, park.longitude).toFixed(2)} km)`;
      nearbyParkItem.classList.add('nearby-park');
      nearbyParkItem.addEventListener('click', () => {
        map.setView([park.latitude, park.longitude], 15);
        L.marker([park.latitude, park.longitude]).addTo(map)
          .bindPopup(`<b>${park.name}</b><br>${park.amenities}`).openPopup();
      });
      nearbyParksContainer.appendChild(nearbyParkItem);
    });
  }

  function getDistance(lat1, lon1, lat2, lon2) {
    const R = 6371, dLat = (lat2 - lat1) * Math.PI / 180, dLon = (lon2 - lon1) * Math.PI / 180;
    const a = Math.sin(dLat / 2) * Math.sin(dLat / 2) + Math.cos(lat1 * Math.PI / 180) * Math.cos(lat2 * Math.PI / 180) * Math.sin(dLon / 2) * Math.sin(dLon / 2);
    return R * 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
  }
});

  </script>
</body>
</html>

I’ve tried different display modes in css but with no luck, it must be something really simple.