/* Basis reset */
* {
  box-sizing: border-box;
}
body {
  font-family: "Roboto", sans-serif;
  margin: 0;
  background: url('../photo/rotterdam-skyline.jpg') no-repeat center center fixed;
  background-size: cover;
  color: #222;
}

/* Transparant / glas-effect */
.header {
  position: fixed;
  width: 100%;
  background: rgba(255,255,255,0.15);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
  box-shadow: 0 0 10px rgba(0,0,0,0.1);
  z-index: 999;
}

.topnav {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
  padding: 0.5rem 1rem;
  font-weight: 600;
}

.topnav a {
  color: #046b1a;
  text-decoration: none;
  padding: 0.6rem 1rem;
  margin: 0 0.2rem;
  border-radius: 5px;
  transition: background-color 0.3s ease;
}

.topnav a:hover, .topnav a.active {
  background-color: rgba(255, 255, 255, 0.4);
}

.topnav .icon {
  display: none;
  cursor: pointer;
  color: rgb(239, 108, 108);
  font-size: 24px;
}

.header-brand {
  display: flex;
  align-items: center;
  padding: 1rem;
  margin-top: 60px;
}

.header-brand h1 {
  color: #45a5f4;
  margin-left: 1rem;
  font-size: 1.6rem;
}

.header-brand p {
  color: #45a5f4;
  margin-left: 1rem;
  font-style: italic;
}

.logo {
  height: 60px;
}

/* Responsive menu */
@media (max-width: 768px) {
  .topnav a:not(:first-child) {
    display: none;
  }
  .topnav a.icon {
    display: block;
  }
}

.topnav.responsive a {
  display: block;
  width: 100%;
  text-align: left;
  padding: 12px 16px;
  border-top: 1px solid rgba(255,255,255,0.2);
}

.topnav.responsive a.icon {
  position: absolute;
  right: 0;
  top: 0;
  padding: 12px 16px;
  border: none;
}

.topnav.responsive {
  position: relative;
}