.home-page .why-section.spiral-ready {
  box-sizing: border-box;
  height: calc(100svh - var(--navbar-height, 72px));
  min-height: 0;
  padding: 0;
  background: #000;
  scroll-margin-top: var(--navbar-height, 72px);
  border-top: 1px solid rgba(134, 204, 225, .09);
  border-bottom: 1px solid rgba(134, 204, 225, .09);
}
.home-page .why-section.spiral-ready::before,
.home-page .why-section.spiral-ready > .interface-lines-background {
  display: none !important;
}
.home-page .why-section.spiral-ready > .container { display: none; }
.home-page .why-section .spiral-why {
  position: absolute;
  inset: 0;
  overflow: hidden;
  background: transparent;
  color: #ecf4f6;
  font-family: 'Microsoft YaHei', 'PingFang SC', sans-serif;
}
.spiral-why__copy {
  position: absolute;
  top: clamp(28px, 5svh, 58px);
  left: max(5vw, calc((100vw - 1220px) / 2));
  z-index: 20;
  width: min(360px, 31vw);
  pointer-events: none;
}
.spiral-why__eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 11px;
  margin-bottom: 25px;
  color: #8aaeb9;
  font: 600 11px/1.3 Arial, sans-serif;
  letter-spacing: .28em;
}
.spiral-why__eyebrow::before { content: ''; width: 31px; height: 1px; background: #82b6c5; }
.spiral-why__title {
  margin: 0 0 20px;
  white-space: pre-line;
  font-size: clamp(36px, 4vw, 66px);
  font-weight: 600;
  letter-spacing: -.04em;
  line-height: 1.15;
}
.spiral-why__intro { margin: 0; color: #9db0b8; font-size: 15px; line-height: 1.9; }
.spiral-why__stage {
  position: absolute;
  top: 46%;
  left: 66%;
  width: 100%;
  height: 100%;
  transform: translate(-50%, -50%);
  perspective: 1220px;
  transform-style: preserve-3d;
  touch-action: pan-y;
  cursor: grab;
  z-index: 2;
}
.spiral-why__stage:active { cursor: grabbing; }
.spiral-why__canvas {
  display: block;
  width: 100%;
  height: 100%;
  pointer-events: none;
}
.spiral-why__footer {
  position: absolute;
  left: max(5vw, calc((100vw - 1220px) / 2));
  right: max(5vw, calc((100vw - 1220px) / 2));
  bottom: clamp(20px, 4svh, 38px);
  z-index: 20;
  display: flex; justify-content: space-between; align-items: end; gap: 24px;
  pointer-events: none;
}
.spiral-why__detail { max-width: 365px; }
.spiral-why__index { color: #8dbdc9; letter-spacing: .24em; font: 600 11px Arial, sans-serif; }
.spiral-why__detail h3 { margin: 10px 0 6px; font-size: 24px; font-weight: 600; }
.spiral-why__detail p { margin: 0; color: #9db0b8; font-size: 13px; line-height: 1.7; }
.spiral-why__controls { display: flex; align-items: center; gap: 11px; pointer-events: auto; }
.spiral-why__controls button {
  width: 42px; height: 42px; border-radius: 50%;
  border: 1px solid #9bc0ca5c; background: #0e1b22a8; color: #d7ecf0;
  font-size: 23px; line-height: 1; cursor: pointer; backdrop-filter: blur(12px);
  transition: background .25s, transform .25s, border-color .25s;
}
.spiral-why__controls button:hover { transform: scale(1.08); background: #214555; border-color: #a8e5ed; }
.spiral-why__count { min-width: 60px; text-align: center; color: #abc2ca; font: 12px Arial, sans-serif; letter-spacing: .1em; }
@media (max-width: 760px) {
  .spiral-why__copy { top: 24px; left: 7vw; width: 86vw; }
  .spiral-why__title { font-size: clamp(34px, 9vw, 48px); margin-bottom: 10px; }
  .spiral-why__intro { font-size: 13px; max-width: 280px; }
  .spiral-why__stage { top: 48%; left: 50%; }
  .spiral-why__footer { left: 7vw; right: 7vw; bottom: 18px; }
  .spiral-why__detail h3 { font-size: 19px; }
  .spiral-why__detail p { display: -webkit-box; -webkit-box-orient: vertical; -webkit-line-clamp: 2; overflow: hidden; font-size: 11px; }
  .spiral-why__controls button { width: 36px; height: 36px; }
}
@media (prefers-reduced-motion: reduce) {
  .spiral-why__controls button { transition: none; }
}