body {
  margin: 0;
  font-family: 'Segoe UI', sans-serif;
  background: linear-gradient(135deg, #4e8cff, #80ffdb);
  color: #fff;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
}

.app {
  text-align: center;
}

h1 {
  margin-bottom: 1.5rem;
}

.circle-container {
  position: relative;
  width: 250px;
  height: 250px;
  margin: 0 auto 2rem;
}

.circle {
  width: 100%;
  height: 100%;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.2);
  border: 4px solid #fff;
  transform: scale(0.7);
  transition: transform 4s ease-in-out;
}

#instruction {
  position: absolute;
  width: 100%;
  top: 50%;
  transform: translateY(-50%);
  font-size: 1.5rem;
}

.controls input {
  width: 60px;
  padding: 0.3rem;
  margin: 0 0.5rem;
}

button {
  margin: 0.5rem;
  padding: 0.6rem 1.2rem;
  border: none;
  border-radius: 8px;
  background: #fff;
  color: #333;
  font-weight: bold;
  cursor: pointer;
  transition: background 0.3s;
}

button:hover {
  background: #eee;
}

button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}