/* ╔══════════════════════════════════════════════════════════════╗
   ║ 📱 BOTTOM SHEET — Mục 15                                       ║
   ║                                                                ║
   ║ Slide-up modal cho mobile (TikTok/Instagram style).           ║
   ║ Auto-fallback sang center modal trên desktop (md+).           ║
   ║                                                                ║
   ║ Usage:                                                         ║
   ║   <div class="x-bs" id="myModal">                              ║
   ║     <div class="x-bs-handle"></div>     ← drag bar             ║
   ║     <div class="x-bs-content">...</div>                       ║
   ║   </div>                                                       ║
   ║   x66BottomSheet.open('myModal')                              ║
   ║   x66BottomSheet.close('myModal')                             ║
   ╚══════════════════════════════════════════════════════════════*/

/* ─── Backdrop ─── */
.x-bs-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.5);
  z-index: 60;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.25s ease-out;
  -webkit-backdrop-filter: blur(2px);
  backdrop-filter: blur(2px);
}
.x-bs-backdrop.is-open {
  opacity: 1;
  pointer-events: auto;
}

/* ─── Sheet ─── */
.x-bs {
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 61;
  background: var(--bg-card, #1a1f29);
  border-top: 1px solid rgba(255,255,255,0.08);
  border-radius: 20px 20px 0 0;
  max-height: 85vh;
  display: flex;
  flex-direction: column;
  transform: translateY(100%);
  transition: transform 0.3s cubic-bezier(0.32, 0.72, 0, 1);
  box-shadow: 0 -10px 40px rgba(0, 0, 0, 0.4);
  /* Safe area bottom (iPhone notch) */
  padding-bottom: env(safe-area-inset-bottom, 0);
}
.x-bs.is-open {
  transform: translateY(0);
}
.x-bs.is-dragging {
  transition: none;
}

/* ─── Drag handle ─── */
.x-bs-handle {
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  cursor: grab;
  touch-action: none;
  user-select: none;
}
.x-bs-handle::before {
  content: '';
  width: 40px;
  height: 4px;
  background: rgba(255,255,255,0.25);
  border-radius: 999px;
  transition: background 0.15s;
}
.x-bs-handle:active::before {
  background: rgba(255,255,255,0.5);
  cursor: grabbing;
}

/* ─── Header (optional) ─── */
.x-bs-header {
  padding: 0 20px 12px;
  flex-shrink: 0;
  border-bottom: 1px solid rgba(255,255,255,0.06);
}
.x-bs-title {
  font-size: 16px;
  font-weight: 800;
  color: #fff;
  margin: 0;
}
.x-bs-close {
  position: absolute;
  top: 8px;
  right: 12px;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: rgba(255,255,255,0.08);
  border: none;
  color: #fff;
  display: grid;
  place-items: center;
  cursor: pointer;
  z-index: 1;
  transition: background 0.15s, transform 0.15s;
}
.x-bs-close:hover {
  background: rgba(255,255,255,0.15);
  transform: scale(1.05);
}

/* ─── Content (scrollable) ─── */
.x-bs-content {
  flex: 1 1 auto;
  overflow-y: auto;
  overscroll-behavior: contain;
  padding: 16px 20px;
  -webkit-overflow-scrolling: touch;
}

/* ─── Snap points (half / full) ─── */
.x-bs[data-snap="half"] {
  max-height: 50vh;
}
.x-bs[data-snap="auto"] {
  max-height: 85vh;
}

/* ═══════════════════════════════════════════════════════════════
   📱 MOBILE ONLY: bottom sheet style
   💻 DESKTOP (md+): convert sang center modal
   ═══════════════════════════════════════════════════════════════*/
@media (min-width: 768px) {
  .x-bs {
    position: fixed;
    left: 50%;
    right: auto;
    bottom: auto;
    top: 50%;
    width: min(540px, calc(100vw - 40px));
    max-height: 80vh;
    border-radius: 16px;
    border: 1px solid rgba(255,255,255,0.08);
    transform: translate(-50%, -50%) scale(0.95);
    opacity: 0;
    transition: transform 0.25s ease-out, opacity 0.2s;
    box-shadow: 0 25px 80px rgba(0,0,0,0.5);
  }
  .x-bs.is-open {
    transform: translate(-50%, -50%) scale(1);
    opacity: 1;
  }
  .x-bs-handle {
    display: none; /* không cần drag handle trên desktop */
  }
  .x-bs-content {
    padding: 20px 24px;
  }
}

/* ─── Reduced motion ─── */
@media (prefers-reduced-motion: reduce) {
  .x-bs, .x-bs-backdrop {
    transition-duration: 0.01ms !important;
  }
}

/* ─── Body lock khi sheet mở ─── */
body.x-bs-lock {
  overflow: hidden;
  /* Prevent iOS rubber-band scroll */
  position: fixed;
  width: 100%;
  height: 100%;
}