.back-to-top {
  position: fixed;
  bottom: 72px;
  right: 28px;
  z-index: 9998;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: linear-gradient(135deg, #1a3050, #0F2239);
  color: white;
  border: 2px solid rgba(255,255,255,0.08);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 2px 10px rgba(0,0,0,0.2);
  opacity: 0;
  transform: translateY(12px);
  transition: all 0.25s cubic-bezier(0.4,0,0.2,1);
  pointer-events: none;
}
.back-to-top.visible {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}
.back-to-top:hover {
  background: linear-gradient(135deg, #FF8F00, #FF6F00);
  border-color: rgba(255,255,255,0.15);
  transform: translateY(-3px);
  box-shadow: 0 4px 14px rgba(255,111,0,0.35);
}
.back-to-top svg { width: 16px; height: 16px; fill: white; }
@media (max-width: 768px) {
  .back-to-top { bottom: 64px; right: 20px; width: 32px; height: 32px; }
  .back-to-top svg { width: 14px; height: 14px; }
}