/* Web Kai — center section dock (cyber SCROLL + PREV/NEXT) */

:root {
  --scroll-dock-h: 92px;
  --scroll-dock-offset: max(clamp(40px, 6vh, 72px), calc(env(safe-area-inset-bottom, 0px) + 20px));
  --scroll-dock-bottom: var(--scroll-dock-offset);
  --scroll-dock-reserve: calc(var(--scroll-dock-offset) + var(--scroll-dock-h) + 14px);
  --scroll-cue-h: var(--scroll-dock-reserve);
  --dock-cyan: #7ae8dc;
  --dock-cyan-dim: rgba(122, 232, 220, 0.55);
  --dock-glow: rgba(93, 255, 200, 0.35);
}

.section > .scroll-cue {
  display: none !important;
}

.section {
  overflow-x: clip !important;
  overflow-y: visible !important;
}

.section-inner {
  overflow-x: clip;
}

.chapter-nav,
#chapter-nav {
  display: none !important;
}

/* Unified column */
.scroll-dock--global {
  position: fixed;
  left: 50%;
  bottom: var(--scroll-dock-bottom);
  transform: translate3d(-50%, 0, 0);
  z-index: 110;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0;
  margin: 0;
  padding: 7px 10px calc(7px + env(safe-area-inset-bottom, 0px));
  min-width: 0;
  border: none;
  background: transparent;
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transition:
    opacity 0.5s ease,
    visibility 0.5s ease;
}

.scroll-dock--global::before {
  content: "";
  position: absolute;
  left: 50%;
  top: 50%;
  width: 1px;
  height: calc(100% - 8px);
  transform: translate3d(-50%, -50%, 0);
  background: linear-gradient(
    180deg,
    rgba(93, 255, 200, 0.08) 0%,
    rgba(93, 255, 200, 0.22) 18%,
    rgba(93, 255, 200, 0.28) 50%,
    rgba(93, 255, 200, 0.22) 82%,
    rgba(93, 255, 200, 0.08) 100%
  );
  opacity: 0.75;
  pointer-events: none;
  animation: scrollDockSpine 4s ease-in-out infinite;
}

.scroll-dock--next-only::before {
  display: none;
}

.scroll-dock--global::after {
  content: "";
  position: absolute;
  inset: -5px -14px;
  border-radius: 999px;
  background: rgba(6, 14, 16, 0.28);
  border: 1px solid rgba(93, 255, 200, 0.08);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  opacity: 0;
  transition: opacity 0.4s ease, border-color 0.4s ease, box-shadow 0.4s ease;
  pointer-events: none;
  z-index: -1;
}

.scroll-dock--global.is-visible {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
}

.scroll-dock--global.is-visible:hover::after,
.scroll-dock--global.is-visible:focus-within::after {
  opacity: 1;
  border-color: rgba(93, 255, 200, 0.14);
  box-shadow: 0 0 32px rgba(93, 255, 200, 0.08);
}

body.is-intro-active .scroll-dock--global,
body.is-intro-active .scroll-dock--global.is-visible {
  opacity: 0 !important;
  visibility: hidden !important;
  pointer-events: none !important;
}

body.is-chapter-changing .scroll-dock--global.is-visible {
  opacity: 0.5;
  pointer-events: none;
}

.scroll-dock__btn {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 3px;
  padding: 5px 10px;
  min-width: 44px;
  border: none;
  background: transparent;
  color: var(--dock-cyan-dim);
  font-family: var(--font-ui);
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
  transition:
    color 0.35s ease,
    transform 0.35s ease,
    text-shadow 0.35s ease;
}

.scroll-dock__btn::before {
  content: "";
  position: absolute;
  inset: 2px 0;
  border-radius: 6px;
  background: radial-gradient(ellipse 80% 70% at 50% 50%, rgba(93, 255, 200, 0.12), transparent 72%);
  opacity: 0;
  transition: opacity 0.35s ease;
  pointer-events: none;
}

.scroll-dock__btn:not(:disabled):not(.is-hidden):hover::before,
.scroll-dock__btn:not(:disabled):not(.is-hidden):focus-visible::before {
  opacity: 1;
}

.scroll-dock__btn:disabled,
.scroll-dock__btn.is-hidden {
  opacity: 0;
  visibility: hidden;
  height: 0;
  min-height: 0;
  padding: 0;
  margin: 0;
  overflow: hidden;
  pointer-events: none;
}

.scroll-dock__arrow {
  font-size: 0.78rem;
  line-height: 1;
  color: var(--dock-cyan);
  text-shadow: 0 0 12px var(--dock-glow);
  transition:
    transform 0.45s ease,
    color 0.35s ease,
    text-shadow 0.35s ease;
}

.scroll-dock__btn--prev .scroll-dock__arrow {
  animation: scrollDockArrowUpIdle 3s ease-in-out infinite;
}

.scroll-dock__arrow--main {
  animation: scrollDockArrowDownIdle 3s ease-in-out infinite;
}

.scroll-dock__hint {
  font-size: 0.48rem;
  font-weight: 400;
  letter-spacing: 0.34em;
  text-transform: uppercase;
  line-height: 1;
  color: rgba(122, 232, 220, 0.58);
  transition: color 0.35s ease, letter-spacing 0.35s ease;
}

.scroll-dock__rail {
  position: relative;
  z-index: 1;
  display: flex;
  justify-content: center;
  padding: 4px 0;
  margin: 1px 0;
}

.scroll-dock__track {
  position: relative;
  display: block;
  width: 1px;
  height: 34px;
  overflow: hidden;
  background: linear-gradient(
    180deg,
    rgba(93, 255, 200, 0.04),
    rgba(93, 255, 200, 0.35) 50%,
    rgba(93, 255, 200, 0.04)
  );
  box-shadow: 0 0 16px rgba(93, 255, 200, 0.12);
  animation: scrollDockTrack 3.6s ease-in-out infinite;
}

.scroll-dock__line {
  display: block;
  width: 100%;
  height: 12px;
  background: linear-gradient(180deg, var(--dock-cyan), rgba(93, 255, 200, 0.75));
  box-shadow: 0 0 16px var(--dock-glow);
  animation: scrollCueLine 2.2s ease-in-out infinite;
}

.scroll-dock.is-pulse-down .scroll-dock__line {
  animation: scrollDockPulseDown 0.65s ease-out;
}

.scroll-dock.is-pulse-up .scroll-dock__line {
  animation: scrollDockPulseUp 0.65s ease-out;
}

.scroll-dock.is-pulse-down .scroll-dock__arrow--main {
  animation: scrollDockArrowDown 0.55s ease-out;
}

.scroll-dock.is-pulse-up .scroll-dock__btn--prev .scroll-dock__arrow {
  animation: scrollDockArrowUp 0.55s ease-out;
}

@media (hover: hover) {
  .scroll-dock__btn:not(:disabled):not(.is-hidden):hover {
    color: var(--dock-cyan);
  }

  .scroll-dock__btn:not(:disabled):not(.is-hidden):hover .scroll-dock__hint {
    color: rgba(122, 232, 220, 0.92);
    letter-spacing: 0.42em;
  }

  .scroll-dock__btn--prev:not(:disabled):hover .scroll-dock__arrow {
    text-shadow: 0 0 20px rgba(93, 255, 200, 0.55);
  }

  .scroll-dock__btn--next:not(:disabled):hover .scroll-dock__arrow--main {
    text-shadow: 0 0 22px rgba(93, 255, 200, 0.6);
  }

  .scroll-dock--global:hover .scroll-dock__track {
    box-shadow: 0 0 24px rgba(93, 255, 200, 0.2);
  }
}

.scroll-dock__btn:focus-visible {
  outline: 1px solid rgba(93, 255, 200, 0.45);
  outline-offset: 4px;
  border-radius: 6px;
}

.scroll-dock--global.is-last .scroll-dock__rail,
.scroll-dock--global.is-last .scroll-dock__btn--next {
  display: none;
}

.scroll-dock--global.is-last::before {
  height: 36%;
  top: 62%;
  transform: translate3d(-50%, -50%, 0);
}

@keyframes scrollDockSpine {
  0%,
  100% {
    opacity: 0.55;
    transform: translate3d(-50%, -50%, 0) scaleY(0.96);
  }
  50% {
    opacity: 0.9;
    transform: translate3d(-50%, -50%, 0) scaleY(1.04);
  }
}

@keyframes scrollDockTrack {
  0%,
  100% {
    transform: scaleY(1);
    opacity: 0.8;
  }
  50% {
    transform: scaleY(1.1);
    opacity: 1;
  }
}

@keyframes scrollDockArrowUpIdle {
  0%,
  100% {
    transform: translate3d(0, 0, 0);
  }
  50% {
    transform: translate3d(0, -3px, 0);
  }
}

@keyframes scrollDockArrowDownIdle {
  0%,
  100% {
    transform: translate3d(0, 0, 0);
  }
  50% {
    transform: translate3d(0, 4px, 0);
  }
}

@keyframes scrollDockPulseDown {
  0% {
    transform: translate3d(0, -90%, 0);
    opacity: 0.15;
  }
  100% {
    transform: translate3d(0, 130%, 0);
    opacity: 1;
  }
}

@keyframes scrollDockPulseUp {
  0% {
    transform: translate3d(0, 90%, 0);
    opacity: 0.15;
  }
  100% {
    transform: translate3d(0, -130%, 0);
    opacity: 1;
  }
}

@keyframes scrollDockArrowDown {
  0% {
    transform: translate3d(0, 0, 0);
  }
  100% {
    transform: translate3d(0, 6px, 0);
  }
}

@keyframes scrollDockArrowUp {
  0% {
    transform: translate3d(0, 0, 0);
  }
  100% {
    transform: translate3d(0, -6px, 0);
  }
}

@media (max-width: 900px) {
  :root {
    --scroll-dock-h: 128px;
    --scroll-dock-offset: max(clamp(40px, 7.5vh, 68px), calc(env(safe-area-inset-bottom, 0px) + 20px));
  }

  .scroll-dock__track {
    height: 30px;
  }

  .scroll-dock__hint {
    font-size: 0.44rem;
    letter-spacing: 0.34em;
  }
}

@media (max-height: 720px) {
  :root {
    --scroll-dock-h: 120px;
    --scroll-dock-offset: max(clamp(36px, 8.5vh, 60px), calc(env(safe-area-inset-bottom, 0px) + 18px));
  }

  .scroll-dock__track {
    height: 26px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .scroll-dock__arrow--main,
  .scroll-dock__btn--prev .scroll-dock__arrow,
  .scroll-dock__track,
  .scroll-dock__line,
  .scroll-dock--global::before {
    animation: none !important;
  }
}