body {
  font-family: sans-serif;
  margin: 0;
  background: #f4f4f4;
}

header {
  background: #2c3e50;
  color: white;
  padding: 1em;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

button {
  padding: 0.5em 1em;
  background: #27ae60;
  color: white;
  border: none;
  border-radius: 5px;
  cursor: pointer;
}

section {
  padding: 1em;
}

.room {
  background: white;
  padding: 1em;
  margin: 1em 0;
  border-radius: 10px;
}

.hidden {
  display: none !important;
}

input[type="text"],
input[type="password"],
input[type="date"],
input[type="number"] {
  width: 100%;
  padding: 0.5em;
  margin: 0.5em 0;
}

ul {
  list-style: none;
  padding: 0;
}

@media (max-width: 600px) {
  header {
    flex-direction: column;
    align-items: flex-start;
  }

  .room {
    width: 95%;
    margin: 10px auto;
  }

  input, button {
    width: 100%;
    margin-top: 0.5em;
  }

  section {
    padding: 0.5em;
  }
}