/* Back to top + circular scroll progress */
.fts-back-top {
  position: fixed;
  right: clamp(16px, 2vw, 28px);
  bottom: clamp(16px, 2.4vw, 32px);
  z-index: 9990;
  width: 52px;
  height: 52px;
  border: none;
  padding: 0;
  border-radius: 50%;
  background: transparent;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(12px) scale(0.92);
  transition: opacity 0.35s ease, visibility 0.35s ease, transform 0.35s cubic-bezier(0.34, 1.2, 0.64, 1);
  box-shadow: 0 10px 28px rgba(15, 13, 29, 0.18);
}

.fts-back-top.is-visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0) scale(1);
}

.fts-back-top:hover {
  transform: translateY(-2px) scale(1.04);
}

.fts-back-top:focus-visible {
  outline: 2px solid var(--ul-primary);
  outline-offset: 3px;
}

.fts-back-top-inner {
  position: absolute;
  inset: 6px;
  border-radius: 50%;
  background: var(--fts-surface, #fff);
  color: var(--ul-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: inset 0 0 0 1px var(--fts-border-soft, rgba(15, 13, 29, 0.08));
  transition: background 0.3s ease, color 0.3s ease, box-shadow 0.3s ease;
}

.fts-back-top:hover .fts-back-top-inner {
  background: var(--ul-primary);
  color: #fff;
  box-shadow: none;
}

.fts-back-top-inner svg {
  width: 18px;
  height: 18px;
  display: block;
}

.fts-back-top-progress {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  transform: rotate(-90deg);
  pointer-events: none;
}

.fts-back-top-progress circle {
  fill: none;
  stroke-width: 3;
}

.fts-back-top-progress .fts-track {
  stroke: var(--fts-border, #d9d9d9);
  opacity: 0.7;
}

.fts-back-top-progress .fts-bar {
  stroke: var(--ul-primary);
  stroke-linecap: round;
  stroke-dasharray: 150.8;
  stroke-dashoffset: 150.8;
  transition: stroke-dashoffset 0.05s linear;
}

html[data-theme="dark"] .fts-back-top {
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.45);
}

html[data-theme="dark"] .fts-back-top-inner {
  background: var(--fts-surface, #151925);
  color: #9eb0ff;
}

html[data-theme="dark"] .fts-back-top:hover .fts-back-top-inner {
  background: var(--ul-primary);
  color: #fff;
}

html[data-theme="dark"] .fts-back-top-progress .fts-track {
  stroke: #2c3345;
}

@media (prefers-reduced-motion: reduce) {
  .fts-back-top,
  .fts-back-top-progress .fts-bar {
    transition: none;
  }
}