.back-to-top-btn {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 50px;
  height: 50px;
  background: var(--mid-green);
  color: white;
  border: none;
  border-radius: 50%;
  font-size: 24px;
  font-weight: bold;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 12px rgba(0,0,0,0.15);
  z-index: 1000;
  transition: all 0.3s ease;
}

.back-to-top-btn:hover {
  background: var(--highlight-green);
  box-shadow: 2px 4px 6px rgba(0,0,0,0.8);
  color: var(--main-green);
}

.back-to-top-btn:active {
  transform: translateY(0);
}

.back-to-top-btn:focus {
  outline: 2px solid #007cba;
  outline-offset: 2px;
}

@media (max-width: 768px) {
  .back-to-top-btn {
    bottom: 20px;
    right: 20px;
    width: 45px;
    height: 45px;
    font-size: 18px;
  }
}