body, html {
  margin: 0;
  padding: 0;
  font-family: 'Segoe UI', sans-serif;
  height: 100%;
  background: url('cloud-computing-00.jpg') no-repeat center center fixed;
  background-size: cover;
  color: white;
}
.overlay {
  position: fixed;
  top: 0; left: 0;
  width: 100%; height: 100%;
  background: rgba(0,0,0,0.5);
  z-index: 1;
}
.container {
  position: relative;
  z-index: 2;
  text-align: center;
  padding: 40px 20px;
}
.logo {
  max-width: 140px;
  margin-bottom: 10px;
}
h1 {
  margin: 0 0 20px;
  font-size: 32px;
}
.menu a {
  display: block;
  background: rgba(255,255,255,0.1);
  color: white;
  margin: 10px auto;
  padding: 12px 18px;
  max-width: 280px;
  text-decoration: none;
  border-radius: 8px;
  font-weight: bold;
  transition: all 0.3s ease;
}
.menu a:hover {
  background: rgba(255,255,255,0.3);
}
.logout {
  color: #ffaaaa;
}
@media screen and (max-width: 600px) {
  .menu a {
    font-size: 16px;
    padding: 10px;
  }
}