:root{
  --bg:#000;
  --fg:#fff;
  --stroke: rgba(255,255,255,.10);
  --glass: rgba(20,20,20,.55);
  --muted: rgba(255,255,255,.78);

  --safeTop: env(safe-area-inset-top);
  --safeBottom: env(safe-area-inset-bottom);
}

*{box-sizing:border-box}
html,body{
  height:100%;
  margin:0;
  padding:0;
  background: var(--bg);
  color: var(--fg);
  overflow-x:hidden !important;
}
body{
  font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial;
}

.app{
  position:relative;
  width:100%;
  height:100svh;
  overflow:hidden;
}

/* TOPBAR: ONLY gift */
.topbar{
  position:fixed;
  top:0; left:0; right:0;
  z-index:40;
  padding: calc(14px + var(--safeTop)) 16px 12px;
  display:flex;
  align-items:center;
  justify-content:space-between;
  background: linear-gradient(to bottom, rgba(0,0,0,.82), rgba(0,0,0,.30), rgba(0,0,0,0));
  pointer-events:none;
}
.topbar > *{pointer-events:auto}
.top-spacer{width:1px;height:1px;opacity:0}

.icon-btn{
  width:44px;height:44px;
  border:none;
  background: transparent;
  color: var(--fg);
  display:grid;
  place-items:center;
  padding:0;
}
.icon-btn svg{width:26px;height:26px}

.main{
  position:absolute;
  inset:0;
  width:100%;
  height:100svh;
}

/* FEED */
.feed{
  position:absolute;
  inset:0;
  width:100%;
  height:100%;
  overflow-y:auto;
  overflow-x:hidden !important;
  scroll-snap-type: y mandatory;
  -webkit-overflow-scrolling: touch;
  background:#000;
}
.slide{
  position:relative;
  height:100svh;
  width:100%;
  scroll-snap-align:start;
  background:#000;
  overflow:hidden;
}
.slide video{
  position:absolute;
  inset:0;
  width:100%;
  height:100%;
  object-fit: cover; /* TikTok style */
  background:#000;
}
.slide::after{
  content:"";
  position:absolute;
  inset:0;
  pointer-events:none;
  background: radial-gradient(120% 80% at 50% 30%, rgba(0,0,0,0) 0%, rgba(0,0,0,.32) 55%, rgba(0,0,0,.72) 100%);
}

/* MUTE FAB */
.mute-fab{
  position: fixed;
  left: 16px;
  top: calc(120px + var(--safeTop));
  z-index: 30;
  width:56px;height:56px;
  border-radius:999px;
  border:1px solid var(--stroke);
  background: var(--glass);
  color: var(--fg);
  display:grid;
  place-items:center;
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);

  /* Tap hint animation */
  opacity: 1;
  transform: translateY(0) scale(1);
  transition: opacity .28s ease, transform .28s ease;
}
.mute-fab svg{width:24px;height:24px}

/* Minimal caption */
.caption{
  position: fixed;
  left: 16px;
  right: 16px;
  bottom: calc(18px + var(--safeBottom));
  z-index: 30;

  font-weight: 900;
  font-size: 18px;
  letter-spacing: .2px;
  color: rgba(255,255,255,.92);
  text-shadow: 0 10px 28px rgba(0,0,0,.65);
  user-select:none;
  pointer-events:none;
  line-height:1.2;

  /* Tap hint animation */
  opacity: 1;
  transform: translateY(0);
  transition: opacity .28s ease, transform .28s ease;
}

/* Toast */
.toast{
  position: fixed;
  left:50%;
  transform: translateX(-50%);
  bottom: calc(70px + var(--safeBottom));
  z-index: 80;
  display:none;
  padding: 10px 12px;
  border-radius: 14px;
  border: 1px solid rgba(255,255,255,.12);
  background: rgba(0,0,0,.60);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  font-weight: 900;
  max-width: 92vw;
}
.toast.show{display:block}

/* ✅ Tap hint hidden state (JS toggles this class) */
.is-hidden{
  opacity: 0 !important;
  transform: translateY(8px) scale(.98) !important;
  pointer-events: none !important;
}
.caption.is-hidden{
  transform: translateY(10px) !important;
}

/* Optional: reduce motion */
@media (prefers-reduced-motion: reduce){
  .mute-fab, .caption{
    transition: none !important;
  }
}

/* Desktop: giữ đúng tỉ lệ video (không crop) */
@media (min-width: 1024px) and (hover: hover) and (pointer: fine){
  .slide video{
    object-fit: contain;
    background:#000;
  }
}