body {
  margin: 0;
  padding: 0;
  background: white;
  height: 100vh;
  overflow: hidden;
  font-family: Arial, sans-serif;

  display: flex;
  justify-content: center;
  align-items: center;
  flex-direction: column;

  transition: background-color 0.4s ease;
}

.main-btn {
  width: 140px;
  height: 140px;
  border-radius: 50%;
  border: 2px solid black;
  background: white;
  color: black;
  font-size: 56px;
  font-weight: bold;
  cursor: pointer;
}

.main-btn:active {
  transform: scale(0.96);
}

.color-btn {
  position: fixed;
  left: 30px;
  bottom: 30px;

  width: 80px;
  height: 80px;
  border-radius: 50%;
  border: none;

  background: rgba(255,255,255,0.95);
  box-shadow: 0 6px 20px rgba(0,0,0,0.15);

  cursor: pointer;
}

.show-img {
  margin-top: 30px;
  width: 300px;
  border-radius: 16px;
  display: none;

  box-shadow: 0 10px 30px rgba(0,0,0,0.15);
}