.royalty-calculator {
  display: block;
  margin: 0 auto;
  margin-bottom: 25px;
  background: #C0C0C0;
  border-radius: 20px;
  padding: 10px 25px 15px 25px;
  width: 300px;
  scale: 0.90;
}

.royalty-calculator-header {
  background: #C0C0C0;
  color: #663399;
  font-family: Arial;
  font-size: 24px;
  font-weight: bold;
  text-align: center;
  margin-bottom: 10px;
}

.display {
  margin-bottom: 20px;
}

#result {
  width: 100%;
  height: 80px;
  background: #4169E1;
  border: none;
  border-radius: 10px;
  color: #FFF;
  font-size: 2.5rem;
  text-align: center;
}

.royalty-calculator-buttons {
  display: grid;
  /* IGNORE ANY WARNINGS! */
  grid-template-columns: repeat(4, 1fr);
  gap: 15px;
}

button {
  height: 60px;
  border: none;
  border-radius: 10px;
  background: #4169E1;
  color: #FFF;
  font-size: 1.5rem;
  font-weight: bold;
  cursor: pointer;
  transition: all 0.2s ease;
}

button:hover {
  background: #663399;
  transform: translateY(-2px);
}

button:active {
  transform: translateY(0);
}

.equals-button {
  background: #663399;
  grid-column: span 2;
}

.equals-button:hover {
  background: #4169E1;
}

button:nth-child(1),
button:nth-child(2),
button:nth-child(3),
button:nth-child(4) {
  background: #663399;
}

button:nth-child(1):hover,
button:nth-child(2):hover,
button:nth-child(3):hover,
button:nth-child(4):hover {
  background: #4169E1;
}