/* 首页 — 五卡折纸 + 整页折叠过渡 */

.page-fold {
  --fold-zone-color: #3b82f6;
}

.page-fold.is-transitioning {
  overflow: hidden;
}

.page-fold .site-header {
  border-bottom-color: transparent;
  background: rgba(15, 20, 25, 0.7);
  z-index: 50;
}

.page-fold .site-footer.fold-footer {
  border-top: none;
  background: transparent;
  padding: 0.75rem 0 1.25rem;
  font-size: 0.8rem;
  position: relative;
  z-index: 10;
}

.fold-page {
  flex: 1;
  display: flex;
  flex-direction: column;
}

.fold-stage {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 1.25rem 1rem 0;
  max-width: 1280px;
  margin: 0 auto;
  width: 100%;
}

/* 标题 */
.fold-intro {
  text-align: center;
  margin-bottom: 1.75rem;
}

.fold-intro-badge {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 0.5rem;
}

.fold-intro h1 {
  margin: 0;
  font-size: clamp(1.5rem, 3.5vw, 2rem);
  font-weight: 700;
  letter-spacing: 0.08em;
}

.fold-intro-sub {
  margin: 0.4rem 0 0;
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* 五卡网格 */
.zone-cards {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 0.75rem;
  width: 100%;
  perspective: 1200px;
}

.zone-card {
  --tilt: -14deg;
  position: relative;
  display: flex;
  flex-direction: column;
  min-height: 220px;
  padding: 1.15rem 1rem 1rem;
  text-decoration: none;
  color: var(--text);
  border-radius: 12px;
  border: 1px solid var(--border);
  background: var(--bg-card);
  transform-style: preserve-3d;
  transform-origin: left center;
  transition:
    transform 0.42s cubic-bezier(0.23, 1, 0.32, 1),
    box-shadow 0.42s ease,
    border-color 0.25s,
    filter 0.35s;
  overflow: hidden;
  cursor: pointer;
}

.zone-card[data-zone="portal"] { --zone-color: #3b82f6; --tilt: -16deg; }
.zone-card[data-zone="dashboard"] { --zone-color: #38bdf8; --tilt: -10deg; }
.zone-card[data-zone="ml"] { --zone-color: #a78bfa; --tilt: -8deg; }
.zone-card[data-zone="ai"] { --zone-color: #f472b6; --tilt: 8deg; }
.zone-card[data-zone="tools"] { --zone-color: #10b981; --tilt: 14deg; }

/* 纸张纹理 */
.zone-card__paper {
  position: absolute;
  inset: 0;
  background:
    linear-gradient(135deg, rgba(255,255,255,0.04) 0%, transparent 45%),
    repeating-linear-gradient(
      -12deg,
      transparent,
      transparent 3px,
      rgba(255,255,255,0.015) 3px,
      rgba(255,255,255,0.015) 4px
    );
  pointer-events: none;
  transition: opacity 0.35s;
}

/* 折痕 */
.zone-card__crease {
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 4px;
  background: linear-gradient(180deg, transparent, var(--zone-color), transparent);
  opacity: 0.35;
  transform-origin: left center;
  transition: width 0.35s, opacity 0.35s, box-shadow 0.35s;
  pointer-events: none;
}

/* 折角 */
.zone-card__corner {
  position: absolute;
  right: 0;
  bottom: 0;
  width: 0;
  height: 0;
  border-style: solid;
  border-width: 0 0 36px 36px;
  border-color: transparent transparent rgba(255,255,255,0.06) transparent;
  transition: border-width 0.4s cubic-bezier(0.23, 1, 0.32, 1), filter 0.35s;
  pointer-events: none;
}

.zone-card__num {
  font-family: var(--mono);
  font-size: 0.72rem;
  font-weight: 500;
  color: var(--zone-color);
  letter-spacing: 0.1em;
  position: relative;
  z-index: 1;
}

.zone-card__title {
  margin: 0.5rem 0 0.35rem;
  font-size: 0.95rem;
  font-weight: 600;
  line-height: 1.35;
  position: relative;
  z-index: 1;
}

.zone-card__desc {
  margin: 0;
  font-size: 0.78rem;
  color: var(--text-muted);
  flex: 1;
  position: relative;
  z-index: 1;
}

.zone-card__enter {
  margin-top: 0.75rem;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--zone-color);
  opacity: 0;
  transform: translateX(-6px);
  transition: opacity 0.3s, transform 0.35s;
  position: relative;
  z-index: 1;
}

/* 悬停：折纸展开 */
.zone-cards:has(.zone-card:hover) .zone-card:not(:hover) {
  opacity: 0.55;
  filter: saturate(0.7) brightness(0.85);
  transform: perspective(900px) rotateY(calc(var(--tilt) * 0.4)) scale(0.94);
}

.zone-card:hover,
.zone-card:focus-visible {
  border-color: var(--zone-color);
  z-index: 5;
  transform: perspective(900px) rotateY(0deg) rotateX(-4deg) translateY(-14px) scale(1.04);
  box-shadow:
    -8px 16px 40px rgba(0, 0, 0, 0.45),
    0 0 0 1px var(--zone-color),
    0 0 48px rgba(59, 130, 246, 0.25);
  text-decoration: none;
  color: var(--text);
}

.zone-card:hover .zone-card__crease,
.zone-card:focus-visible .zone-card__crease {
  width: 6px;
  opacity: 1;
  box-shadow: 2px 0 12px var(--zone-color);
}

.zone-card:hover .zone-card__corner,
.zone-card:focus-visible .zone-card__corner {
  border-width: 0 0 52px 52px;
  border-color: transparent transparent rgba(255, 255, 255, 0.12) transparent;
  filter: drop-shadow(0 0 8px var(--zone-color));
}

.zone-card:hover .zone-card__enter,
.zone-card:focus-visible .zone-card__enter {
  opacity: 1;
  transform: translateX(0);
}

.zone-card:hover .zone-card__paper {
  opacity: 1;
  animation: paper-shimmer 1.2s ease-out;
}

@keyframes paper-shimmer {
  0% { opacity: 0.5; }
  40% { opacity: 1; }
  100% { opacity: 1; }
}

.zone-card.is-pressed {
  transform: perspective(900px) rotateY(2deg) scale(0.98) !important;
  transition-duration: 0.12s;
}

/* 整页折叠过渡 */
.fold-transition {
  position: fixed;
  inset: 0;
  z-index: 9999;
  pointer-events: none;
  perspective: 1400px;
}

.fold-transition[hidden] {
  display: none;
}

.fold-transition.is-active {
  pointer-events: all;
}

.fold-transition__veil {
  position: absolute;
  inset: 0;
  background: var(--bg);
  opacity: 0;
  transition: opacity 0.15s;
}

.fold-transition.is-active .fold-transition__veil {
  opacity: 1;
  transition: opacity 0.1s 0.05s;
}

.fold-transition__sheet {
  position: absolute;
  top: 0;
  bottom: 0;
  width: 50%;
  background: linear-gradient(145deg, var(--bg-elevated), var(--bg));
  border: 1px solid var(--border);
  transform-style: preserve-3d;
  backface-visibility: hidden;
  box-shadow: inset 0 0 80px rgba(0, 0, 0, 0.4);
}

.fold-transition__sheet--left {
  left: 0;
  transform-origin: right center;
  border-right: 2px solid var(--fold-zone-color, var(--accent));
}

.fold-transition__sheet--right {
  right: 0;
  transform-origin: left center;
  border-left: 2px solid var(--fold-zone-color, var(--accent));
}

.fold-transition__crease {
  position: absolute;
  left: 50%;
  top: 0;
  bottom: 0;
  width: 3px;
  margin-left: -1px;
  background: var(--fold-zone-color, var(--accent));
  box-shadow: 0 0 24px var(--fold-zone-color, var(--accent));
  opacity: 0;
  transform: scaleY(0);
  transform-origin: center top;
}

.fold-transition.is-active .fold-transition__sheet--left {
  animation: fold-left 0.85s cubic-bezier(0.55, 0.06, 0.22, 0.99) forwards;
}

.fold-transition.is-active .fold-transition__sheet--right {
  animation: fold-right 0.85s cubic-bezier(0.55, 0.06, 0.22, 0.99) forwards;
}

.fold-transition.is-active .fold-transition__crease {
  animation: crease-flash 0.85s ease-out forwards;
}

@keyframes fold-left {
  0% { transform: rotateY(0deg); }
  100% { transform: rotateY(88deg); }
}

@keyframes fold-right {
  0% { transform: rotateY(0deg); }
  100% { transform: rotateY(-88deg); }
}

@keyframes crease-flash {
  0% { opacity: 0; transform: scaleY(0); }
  25% { opacity: 1; transform: scaleY(1); }
  100% { opacity: 0.6; transform: scaleY(1); }
}

/* 折入方向变体 */
.fold-transition[data-fold-dir="left"].is-active .fold-transition__sheet--left {
  animation-name: fold-left-strong;
}

@keyframes fold-left-strong {
  0% { transform: rotateY(0deg); }
  100% { transform: rotateY(92deg); }
}

.fold-transition[data-fold-dir="right"].is-active .fold-transition__sheet--right {
  animation-name: fold-right-strong;
}

@keyframes fold-right-strong {
  0% { transform: rotateY(0deg); }
  100% { transform: rotateY(-92deg); }
}

/* 页内元素在过渡时淡出 */
.page-fold.is-transitioning .fold-page,
.page-fold.is-transitioning .site-header,
.page-fold.is-transitioning .site-footer {
  animation: page-fade-out 0.5s ease forwards;
}

@keyframes page-fade-out {
  to {
    opacity: 0;
    transform: scale(0.98);
    filter: blur(4px);
  }
}

/* 底部 */
.fold-legend {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  margin: 1.5rem 0 0.5rem;
  font-size: 0.8rem;
  color: var(--text-muted);
}

.fold-sound-toggle {
  font-family: inherit;
  font-size: 0.75rem;
  padding: 0.3rem 0.65rem;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--bg-elevated);
  color: var(--text-muted);
  cursor: pointer;
  transition: border-color 0.2s, color 0.2s;
}

.fold-sound-toggle:hover {
  border-color: var(--accent);
  color: var(--text);
}

.fold-sound-toggle[aria-pressed="false"] {
  opacity: 0.55;
}

/* 平板 */
@media (max-width: 1024px) {
  .zone-cards {
    grid-template-columns: repeat(2, 1fr);
    gap: 0.65rem;
  }
  .zone-card:nth-child(5) {
    grid-column: 1 / -1;
    max-width: none;
  }
}

/* 手机 — 单列大按钮卡片 */
@media (max-width: 768px) {
  .fold-stage {
    padding: 0.75rem 0.75rem 0;
    min-height: auto;
  }

  .fold-intro {
    margin-bottom: 1.25rem;
  }

  .fold-intro h1 {
    font-size: 1.5rem;
  }

  .zone-cards {
    grid-template-columns: 1fr;
    gap: 0.65rem;
    max-width: none;
    perspective: none;
  }

  .zone-card {
    min-height: auto;
    padding: 1rem 1.1rem;
    transform-origin: center center;
    transform: none !important;
    filter: none !important;
    opacity: 1 !important;
  }

  .zone-card__enter {
    opacity: 1;
    transform: none;
    margin-top: 0.5rem;
    min-height: var(--touch-min, 44px);
    display: inline-flex;
    align-items: center;
  }

  .zone-cards:has(.zone-card:hover) .zone-card:not(:hover) {
    opacity: 1;
    filter: none;
    transform: none;
  }

  .zone-card:active {
    transform: scale(0.98) !important;
    border-color: var(--zone-color);
  }

  .fold-legend {
    flex-direction: column;
    gap: 0.5rem;
    margin-top: 1rem;
  }

  .fold-sound-toggle {
    min-width: var(--touch-min, 44px);
  }
}

/* 触控设备：弱化悬停 3D，避免粘滞 */
@media (hover: none) and (pointer: coarse) {
  .zone-cards:has(.zone-card:hover) .zone-card:not(:hover) {
    opacity: 1;
    filter: none;
    transform: none;
  }

  .zone-card:hover {
    transform: none;
    box-shadow: none;
  }

  .zone-card__enter {
    opacity: 1;
    transform: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  .zone-card,
  .zone-cards:has(.zone-card:hover) .zone-card:not(:hover) {
    transition: border-color 0.15s, box-shadow 0.15s;
  }
  .zone-card:hover {
    transform: translateY(-4px);
  }
  .fold-transition.is-active .fold-transition__sheet--left,
  .fold-transition.is-active .fold-transition__sheet--right {
    animation-duration: 0.2s;
  }
  .page-fold.is-transitioning .fold-page,
  .page-fold.is-transitioning .site-header,
  .page-fold.is-transitioning .site-footer {
    animation: none;
    opacity: 0;
  }
}