/* ===== right black layer ===== */
body::before {
  content: "";
  position: fixed;
  top: 0;
  right: 0;
  width: 3px;
  height: 100vh;
  background: #000;
  z-index: 1;
  pointer-events: none;

   /* animation */
   transform: translateX(0);
   transition: transform 0.45s cubic-bezier(0.4, 0, 0.2, 1);
}
/* right edge nudge */
body.edge-nudge::before {
  transform: translateX(10px);
}


/* ===== nav===== */
.sidebar {
  position: fixed;
  top: 0;
  right: var(--gap);
  height: 100%;
  display: flex;
  flex-direction: row-reverse;
  z-index: 1000;
  cursor: default;
}

.sidebar::before {
  content: "";
  position: fixed;
  top: 0;
  right: 30px;
  width: calc(var(--tab-w) * 3);
  height: 100vh;
  background: #fff;
  z-index: 1499; 
  pointer-events: none;
}

.sidebar::after {
  content: "";
  position: fixed;
  top: 0;
  right: var(--gap);
  width: calc(var(--tab-w) * 5);
  height: 100vh;
  background:
    repeating-linear-gradient(
      to left,
      var(--color) 0,
      var(--color) var(--line),
      transparent var(--line),
      transparent var(--tab-w)
    ),
    #fff;
  background-size: calc(var(--tab-w) * 5) 100%, 100% 100%;
  background-position: right 0 top 0, right 0 top 0;
  z-index: 1500;
  pointer-events: none;
}




.tab {
  position: relative;
  width: var(--tab-w);
  height: 100%;

  border-right: none;
  /* background: #fff; */
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: default;
  overflow: hidden;
  transition: width var(--dur) var(--ease);
  pointer-events: none;
}

.tab span {
  font-size: 13.3px;
  transition: opacity 0.4s ease, transform 0s ease;
}
.tab .short { opacity: 1; }
.tab .full  { opacity: 0; margin-left: 8px; }

.tab.active {
  position: fixed;         
  top: 0;
  left: 50%;              
  transform: translateX(-50%);
  width: calc(100% - (var(--gap) * 2));
  height: 100vh;
  padding: 120px var(--gap) var(--gap);
  box-sizing: border-box;
  overflow-y: auto;
  scrollbar-width: none;
  z-index: 3000;
  justify-content: flex-start;
  animation: slideFromRightToCenter 0.3s var(--ease);
  pointer-events: auto;
  background: #fff;
}

@keyframes slideFromRightToCenter {
  from {
    opacity: 0;
    left: calc(100% - var(--gap));
    transform: translateX(-100%);
    width: calc(100vw - (var(--tab-w) * 5) - var(--gap));
  }
  to {
    opacity: 1;
    left: 50%;
    transform: translateX(-50%);
    width: calc(100vw - (var(--gap) * 2));
  }
}

.tab.active iframe {
  display: block;
  height: calc(100vh - 120px - var(--gap));
  animation: fadeInFromRight 0.8s var(--ease);
}

@keyframes fadeInFromRight {
  from {
    opacity: 0;
    transform: translateX(40px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

.tab.active::-webkit-scrollbar { width: 0; height: 0; }


@media (max-width: 768px) {
  :root {
    --tab-w-mobile: 8px; 
    --line-mobile: 1px; 
    --sidebar-width-mobile: 40px; 
  }
  
  .tab.active {
    width: calc(100vw - (var(--gap) * 2));
    padding: 90px var(--gap) var(--gap);
    height: 100vh;
    background: #fff;
  }
  

  .sidebar::before {
    width: var(--sidebar-width-mobile);
    right: var(--gap);
  }

  .sidebar::after {
    width: var(--sidebar-width-mobile);
    right: var(--gap);
    height: 100vh;
    background:
      repeating-linear-gradient(
        to left,
        var(--color) 0,
        var(--color) var(--line-mobile),
        transparent var(--line-mobile),
        transparent var(--tab-w-mobile)
      ),
      #fff;
    background-size: var(--sidebar-width-mobile) 100%, 100% 100%;
    background-position: 0 0, 0 0;
    background-repeat: no-repeat;
  }
  
  .tab {
    width: var(--tab-w-mobile);
  }
}


.tab iframe {
  width: 100%;
  height: 100%;
  border: 0;
  background: #fff;
  display: block; 
  margin: 0;
}


@keyframes contentSlideInFromRight {
  from {
    opacity: 0;
    transform: translateX(60px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

.content-slide-in {
  opacity: 0;
  animation: contentSlideInFromRight 0.8s var(--ease) forwards;
}

.tab-labels {
  position: fixed;
  top: 0;
  right: var(--gap);
  height: 100%;
  width: calc(var(--tab-w) * 5);
  pointer-events: none;
  z-index: 2000;
  cursor: default;
}

/* ===== layer ===== */
.tab[data-id="book"] { z-index: 10; }
.tab[data-id="lunar_practices"] { z-index: 40; }
.tab[data-id="exhibitions"] { z-index: 30; }
.tab[data-id="events"] { z-index: 20; }
.tab[data-id="about"] { z-index: 50; }


.tab-labels .label {
  position: absolute;
  top: var(--y);
  right: var(--x);
  height: 16px;
  background: #f5f5f5;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0px 6px;
  cursor: default;
  pointer-events: auto;
  transition: transform 0.2s ease-out; 
  overflow: visible; 
}


.tab-labels .label::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%; 
  height: var(--line);
  background: var(--color);
  pointer-events: none; 
  transition: width 0.8s var(--ease); 
}

.tab-labels .label span {
  font-family: var(--font);
  font-size: 12px;
  transition: opacity 0.8s ease, transform 0.8s ease;
  white-space: nowrap;
  line-height: 14px; 
  display: inline-block;
  vertical-align: middle;
  cursor: pointer;
  pointer-events: auto;
}

.tab-labels .label .short {
  opacity: 1;
  transform: translateX(0);
}

.tab-labels .label .full {
  position: relative; 
  margin-left: 0;
  opacity: 0;
  max-width: 0;      
  overflow: hidden;    
  transition: max-width 0.8s var(--ease), opacity 0.8s ease; 
  will-change: max-width;
  text-align: center; 
  pointer-events: none; 
  cursor: pointer;
}

.tab-labels .label .full .char {
  display: inline-block;
  transform: translateX(2px);
  opacity: 0;
  transition: transform 0.3s var(--ease), opacity 0.2s ease; 
  pointer-events: none; 
}

.tab-labels .label.active {
  transform: translateX(-2px);
}

.tab-labels .label.active .full {
  opacity: 1;
  max-width: 200px; 
  pointer-events: auto;
}

.tab-labels .label.active .full .char {
  transform: translateX(0);
  opacity: 1;
}

.tab-labels .label.active .short {
  opacity: 0;
  transform: translateX(-5px);
}

@media (max-width: 768px) {
  .tab-labels { 
    display: block; 
    right: var(--gap);
    width: var(--sidebar-width-mobile); 
  }
  .tab-labels .label { height: 18px; padding: 0 1px; }
  .tab-labels .label span { font-size: 11px; line-height: 18px; }
  .tab-labels .label .full { max-width: 0; }
}

/* ===== idle overlay ===== */
.idle-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(255, 255, 255, 0.85); /* 85%  */
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 10000; 
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.8s ease;
}

.idle-overlay.active {
  opacity: 1;
  pointer-events: auto;
}

.idle-overlay .idle-svg {
  width: 450px;
  height: auto;
  pointer-events: none;
}