body {
  background: #c4dafa;
  margin: 0;
  font-family: 'Segoe UI', Arial, sans-serif;
}
h1 {
  background: #005187;
  color: #fff;
  padding: 1rem 0;
  margin: 0 0 2rem 0;
  text-align: center;
  font-size: 2rem;
  transition: background 0.5s;
}
#colorDisplay {
  font-weight: bold;
  font-size: 1.2rem;
  letter-spacing: 2px;
}
#stripe {
  text-align: center;
  margin-bottom: 2rem;
}
button {
  background: #4d82bc;
  border: none;
  border-radius: 8px;
  color: white;
  padding: 0.7rem 1.4rem;
  margin: 0 0.2rem;
  cursor: pointer;
  font-size: 1rem;
  transition: background 0.3s;
  outline: none;
}
button.selected,
button:hover {
  background: #005187;
}
#message {
  color: #ff4081;
  font-weight: bold;
  margin: 0 1rem;
  min-width: 120px;
  display: inline-block;
}
#container {
  max-width: 600px;
  margin: 0 auto;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 1rem;
}
.square {
  width: 30%;
  padding-bottom: 30%;
  margin: 1%;
  background: #84b6f4;
  display: inline-block;
  border-radius: 12px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.15);
  cursor: pointer;
  transition: background 0.4s, opacity 0.3s;
}
.square[hidden] {
  display: none;
}