body {
    background-color: black;
}

.mainbar {
    width: 100%;
    position: fixed;
    top: 0;
}
.navbar {
    z-index: 1;
    position: fixed;
    right: 0;
    top: 0;
    font-size: 30px;
    font-family: 'Courier New', Courier, monospace;
    padding-right: 15px;
    padding-top: 15px;
}

.navbar a {
    color: white;
    z-index: 1;
    text-decoration: none;
}

.gallery {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-around;
    margin-top: 100px;
}

.gallery img {
    box-sizing: border-box;
    width: 100%;
    height: auto;
    border: 1px solid #ccc;
    padding: 20px;
}

.responsive {
    padding: 0 6px;
    float: left;
    width: 24.99999%;
}
  
@media only screen and (max-width: 700px) {
    .responsive {
      width: 49.99999%;
      margin: 6px 0;
    }
}
  
@media only screen and (max-width: 500px) {
    .responsive {
      width: 100%;
    }
}