body {
  font-family: sans-serif;
  margin: 0;
  padding: 0;
  background: #f5f5f5;
}
#languageToggle {
  text-align: right;
  padding: 10px;
}
#nav {
  display: flex;
  justify-content: space-around;
  background: #222;
  color: #fff;
}
#nav button {
  flex: 1;
  padding: 15px 5px;
  background: none;
  border: none;
  color: inherit;
  font-size: 14px;
}
#content {
  padding: 20px;
}
.card {
  border: 1px solid #ccc;
  background: #fff;
  margin: 10px 0;
  padding: 10px;
}
.card button {
  margin-top: 10px;
}
.hidden { display: none; }