/* Back to Top Button */
.msb-back-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background-color: #3ba9ff;
  color: #fff;
  border: none;
  font-size: 22px;
  font-weight: bold;
  cursor: pointer;
  display: none; /* hidden until scroll */
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 12px rgba(0,0,0,0.25);
  z-index: 9999;
  transition: opacity 0.3s ease, transform 0.3s ease;
}

.msb-back-to-top:hover {
  background-color: #1e6fd8;
  transform: translateY(-3px);
}

/* Dark‑mode adaptation */
@media (prefers-color-scheme: dark) {
  .msb-back-to-top {
    background-color: #7ec3ff;
    color: #0d1628;
  }

  .msb-back-to-top:hover {
    background-color: #3ba9ff;
  }
}