/* 仅账单页的悬浮返回按钮；不改变现有滚动结构。 */
.list-back-top {
  position: fixed;
  right: max(16px, calc((100vw - var(--app-max-width)) / 2 + 16px));
  bottom: calc(var(--tab-bar-height) + var(--safe-area-bottom) + 64px);
  z-index: 40;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 1px;
  width: 48px;
  height: 52px;
  padding: 4px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  background: var(--color-surface);
  color: var(--color-primary);
  box-shadow: var(--shadow-md);
  font-size: 11px;
  font-weight: 600;
  cursor: pointer;
  touch-action: manipulation;
  opacity: 1;
  visibility: visible;
  transition: opacity 200ms ease, visibility 0s, transform 150ms ease, background 150ms ease;
}
.list-back-top[hidden] { display: none; }
.list-back-top--idle {
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transition: opacity 250ms ease, visibility 0s 250ms, transform 150ms ease, background 150ms ease;
}
.list-back-top svg {
  width: 21px;
  height: 21px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.8;
  stroke-linecap: round;
  stroke-linejoin: round;
}
.list-back-top:active { transform: scale(0.94); background: var(--color-primary-light); }
.list-back-top:focus-visible { outline: 2px solid var(--color-primary); outline-offset: 3px; }
@media (hover: hover) { .list-back-top:hover { background: var(--color-primary-light); } }
@media (prefers-reduced-motion: reduce) { .list-back-top { transition: none; } }