.theme-toggle {
  position: fixed;
  top: 20px;
  right: 20px;
  z-index: 1200;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border: 1px solid rgba(15, 23, 42, .14);
  border-radius: 50%;
  background: rgba(255, 255, 255, .88);
  color: #172033;
  box-shadow: 0 10px 28px rgba(15, 23, 42, .16);
  backdrop-filter: blur(18px) saturate(180%);
  -webkit-backdrop-filter: blur(18px) saturate(180%);
  cursor: pointer;
  font-size: 20px;
  line-height: 1;
  transition: transform .2s ease, box-shadow .2s ease, background .2s ease, color .2s ease;
}

.theme-toggle:hover {
  transform: translateY(-1px);
  box-shadow: 0 14px 34px rgba(15, 23, 42, .2);
}

.theme-toggle:focus-visible {
  outline: 3px solid rgba(96, 165, 250, .45);
  outline-offset: 3px;
}

.dark-mode .theme-toggle {
  border-color: rgba(255, 255, 255, .16);
  background: rgba(15, 23, 42, .9);
  color: #e5e7eb;
  box-shadow: 0 14px 36px rgba(0, 0, 0, .34);
}

@media (max-width: 768px) {
  .theme-toggle {
    top: 14px;
    right: 14px;
    width: 40px;
    height: 40px;
  }
}