footer {
  text-align: center;
  margin-top: 5rem;
  font-size: 0.9rem;
  color: var(--text-secondary-color);
}

#back-to-top {
  position: fixed;
  bottom: 40px;
  right: 40px;
  width: 50px;
  height: 50px;
  background-color: var(--theme-color);
  color: white;
  border: none;
  border-radius: 50%;
  cursor: pointer;
  font-size: 1.5rem;
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 100;
  box-shadow: var(--shadow-sm);
  transition: opacity 0.3s ease, transform 0.3s ease;
}

#back-to-top:hover {
  opacity: 0.85;
  transform: scale(1.1);
}

@media (max-width: 600px) {
  footer {
    font-size: 0.65rem;
  }

  #back-to-top {
    bottom: 20px;
    right: 20px;
    width: 40px;
    height: 40px;
    font-size: 1.2rem;
  }
}