Javascript-форум - Появление лишних отступов в мобильной версии

Привет, всем! Помогите, пожалуйста, мучаюсь уже не первый день, уже как только не искала в гугле, но все никак не могу найти ответа, создала сайт используя Bootstrap 4, проблема в том, что когда смотрю сайт с мобильного телефона получается огромный отступ, подскажите, пожалуйста, как можно это исправить:

сайт: https://oloiao.000webhostapp.com/?fb...Csuuutph-I7pPw
проблема тут: https://cdn1.savepice.ru/uploads/201...8ba91-full.png

<!doctype html>
<html lang="en">
  <head>
    <!-- Required meta tags -->
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">

    <!-- Bootstrap CSS -->
    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous">
    <script src="//maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js"></script>
    <script src="//cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
    <link rel="stylesheet" type="text/css" href="example.css">
    <title>Web Masters App</title>

  </head>
  <body>
    <nav class="navbar navbar-expand-lg navbar-dark ">
      <a class="navbar-brand" href="#"><img src="logo.png"  height="50" alt=""></a>
      <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarNav" aria-controls="navbarNav" aria-expanded="false" aria-label="Toggle navigation">
        <span class="navbar-toggler-icon"></span>
      </button>
      <div class="collapse navbar-collapse" id="navbarNav">
        <ul class="navbar-nav">
          <li class="nav-item active">
            <a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
          </li>
          <li class="nav-item">
            <a class="nav-link" href="#">Features</a>
          </li>
          <li class="nav-item">
            <a class="nav-link" href="#">About</a>
          </li>
          <li class="nav-item dropdown">
            <a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">More</a>
            <div class="dropdown-menu" aria-labelledby="navbarDropdown">
              <a class="dropdown-item" href="#">Action</a>
              <a class="dropdown-item" href="#">Another action</a>
              <div class="dropdown-divider"></div>
              <a class="dropdown-item" href="#">Something else here</a>
            </div>
          </li>
        </ul>
      </div>
    </nav>
    <div id="carouselExampleIndicators" class="carousel slide " data-ride="carousel">
      <div class="carousel-inner">
        <div class="carousel-item active">
          <img src="carousel-image1.jpg" class="d-block w-100" alt="...">
          <div class="carousel-caption ">
            <button>Get Started</button>
              <h2>Do you want to master web development?</h2>

            </div>
        </div>
        <div class="carousel-item">
          <img src="carousel-image2.jpg" class="d-block w-100" alt="...">
        </div>
        <div class="carousel-item">
          <img src="carousel-image3.jpg" class="d-block w-100" alt="...">
        </div>
      </div>
      <a class="carousel-control-prev" href="#carouselExampleIndicators" role="button" data-slide="prev">
        <span class="carousel-control-prev-icon" aria-hidden="true"></span>
        <span class="sr-only">Previous</span>
      </a>
      <a class="carousel-control-next" href="#carouselExampleIndicators" role="button" data-slide="next">
        <span class="carousel-control-next-icon" aria-hidden="true"></span>
        <span class="sr-only">Next</span>
      </a>
    </div>

    <div class="container">

    <div class="card-deck">
  <div class="card" >
    <img src="html5.png"  class="card-img-top" alt="...">
    <div class="card-body">
      <h5 class="card-title">Card title</h5>
      <p class="card-text">This is a wider card with supporting text below as a natural lead-in to additional content. This content is a little bit longer.</p>
    </div>
    <div class="card-footer">
      <small class="text-muted">Last updated 3 mins ago</small>
    </div>
  </div>

  <div class="card" >
    <img src="css3.png"  class="card-img-top" alt="...">
    <div class="card-body">
      <h5 class="card-title">Card title</h5>
      <p class="card-text">This card has supporting text below as a natural lead-in to additional content.</p>
    </div>
    <div class="card-footer">
      <small class="text-muted">Last updated 3 mins ago</small>
    </div>
  </div>
  <div class="card">
    <img src="javascript.png" class="card-img-top" alt="...">
    <div class="card-body">
      <h5 class="card-title">Card title</h5>
      <p class="card-text">This is a wider card with supporting text below as a natural lead-in to additional content. This card has even longer content than the first to show that equal height action.</p>
    </div>
    <div class="card-footer">
      <small class="text-muted">Last updated 3 mins ago</small>
    </div>
  </div>
</div>
<div class="card-deck">
<div class="card">
<img src="jQuery.png" class="card-img-top" alt="...">
<div class="card-body">
  <h5 class="card-title">Card title</h5>
  <p class="card-text">This is a wider card with supporting text below as a natural lead-in to additional content. This content is a little bit longer.</p>
</div>
<div class="card-footer">
  <small class="text-muted">Last updated 3 mins ago</small>
</div>
</div>
<div class="card">
<img src="bootstrap.png" class="card-img-top" alt="...">
<div class="card-body">
  <h5 class="card-title">Card title</h5>
  <p class="card-text">This card has supporting text below as a natural lead-in to additional content.</p>
</div>
<div class="card-footer">
  <small class="text-muted">Last updated 3 mins ago</small>
</div>
</div>
<div class="card">
<img src="php.png" class="card-img-top" alt="...">
<div class="card-body">
  <h5 class="card-title">Card title</h5>
  <p class="card-text">This is a wider card with supporting text below as a natural lead-in to additional content. This card has even longer content than the first to show that equal height action.</p>
</div>
<div class="card-footer">
  <small class="text-muted">Last updated 3 mins ago</small>
</div>
</div>

  </body>
</html>

.navbar{
  background-color: #4400ff;
  font-size: 20px;
}
.carousel-control-prev-icon,
.carousel-control-next-icon {
 height: 160px;
 width: 160px;
 outline: black;
 background-size: 100%, 100%;
 background-image: none;
}
.carousel-control-next-icon:after
{
  content: '>';
  font-size: 55px;
  color: #4400ff;
}

.carousel-control-prev-icon:after {
  content: '<';
  font-size: 55px;
  color: #4400ff;
}

.carousel-inner{
  height: 80vh;
}

.carousel-caption{
  top: 50%;
  transform: translateY(-50%);
  background: rgba(76, 0, 255, 0.5);
  bottom: initial;
}

.card{
  margin: 50px;
}