/* 工具按钮浮动样式（回到顶部 / 暗色切换 / 代码复制） */
.return-to-top,
.dark-mode-toggle {
  position: fixed;
  right: 24px;
  width: 42px;
  height: 42px;
  border-radius: 50%;
  border: 1px solid #eee;
  background: #fff;
  color: var(--font-color-2);
  font-size: 18px;
  cursor: pointer;
  box-shadow: 0 2px 8px rgba(0,0,0,.12);
  z-index: 999;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transition: opacity .3s ease, transform .3s ease;
}
.return-to-top { bottom: 84px; }
.dark-mode-toggle { bottom: 24px; }
.return-to-top.show { opacity: 1; }
.dark-mode-toggle { opacity: 1; }
.return-to-top:hover,
.dark-mode-toggle:hover { transform: translateY(-2px); color: var(--font-color-0); }

.code-copy {
  position: absolute;
  top: 8px;
  right: 8px;
  padding: 2px 10px;
  font-size: 12px;
  border-radius: 4px;
  border: 1px solid #eee;
  background: #fff;
  color: var(--font-color-2);
  cursor: pointer;
  opacity: .6;
  transition: opacity .3s;
}
.code-copy:hover { opacity: 1; color: var(--font-color-0); }

html[data-theme="dark"] .return-to-top,
html.dark .return-to-top,
html[data-theme="dark"] .dark-mode-toggle,
html.dark .dark-mode-toggle {
  background: #333;
  border-color: #444;
  color: #ddd;
}