body {
  font-family: 'Poppins', sans-serif;
  text-align: center;
  background-color: #f0f8ff;
  padding: 20px;
}

h1 {
  margin-bottom: 20px;
}

.input-container {
  margin-bottom: 20px;
}

input[type="number"] {
  padding: 10px;
  font-size: 16px;
  width: 200px;
  border: 1px solid #ccc;
  border-radius: 5px;
}

button {
  padding: 10px 20px;
  font-size: 16px;
  margin-left: 10px;
  background-color: #1f6feb;
  color: white;
  border: none;
  border-radius: 5px;
  cursor: pointer;
}

#grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, 50px);
  justify-content: center;
  gap: 5px;
  max-width: 1000px;
  margin: 0 auto;
}

.number {
  width: 50px;
  height: 50px;
  font-size: 16px;
  line-height: 50px;
  text-align: center;
  border: 1px solid #aaa;
  border-radius: 5px;
  background-color: #fdfdfd;
}

.prime {
  background-color: #28a745;
  color: white;
  font-weight: bold;
}

.non-prime {
  background-color: #dc3545;
  color: white;
}