/* Kole UI BackToTop 样式 — 对齐 组件7.txt BackToTop：滚动超阈值出现，右下角悬浮，带进度环 */

.kole-backtop {
  position: fixed; right: 32px; bottom: 32px; width: 44px; height: 44px;
  border-radius: 50%; background: var(--kole-color-card-bg); border: 1px solid var(--kole-color-border);
  box-shadow: 0 4px 12px rgba(0,0,0,0.12); cursor: pointer;
  display: flex; align-items: center; justify-content: center; z-index: 1000;
  opacity: 0; transform: translateY(12px); pointer-events: none;
  transition: opacity .2s, transform .2s, background .15s;
}
.kole-backtop.is-visible { opacity: 1; transform: translateY(0); pointer-events: auto; }
.kole-backtop:hover { background: var(--kole-color-brand-bg); }
.kole-backtop svg { position: absolute; top: 0; left: 0; width: 44px; height: 44px; transform: rotate(-90deg); }
.kole-backtop-ring-bg { stroke: var(--kole-color-border); }
.kole-backtop-ring-fg { stroke: var(--kole-color-brand); transition: stroke-dashoffset .1s linear; }
.kole-backtop-arrow { color: var(--kole-color-brand); font-size: 18px; line-height: 1; z-index: 1; }
.kole-backtop.kole-no-ring .kole-backtop-ring-fg,
.kole-backtop.kole-no-ring .kole-backtop-ring-bg { display: none; }