header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(15, 15, 15, 0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid #1a1a1a;
  padding: 8px 12px;
  transition: padding 0.3s ease, height 0.3s ease;
}

header.collapsed {
  padding: 6px 12px;
  height: 70px;
}

.header-inner {
  max-width: 960px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
}

.controls {
  display: flex;
  flex-wrap: nowrap;
  gap: 8px;
  justify-content: center;
  width: 100%;
  overflow-x: auto;
  padding: 4px 0;
}

.collapsible-header-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  transition: opacity 0.3s ease, height 0.3s ease, margin 0.3s ease;
}

header.collapsed .collapsible-header-content {
  opacity: 0;
  height: 0;
  margin: 0;
  overflow: hidden;
}

main {
  padding-top: 100px;
  min-height: 100vh;
  transition: padding-top 0.3s ease;
}

main.fullscreen-mode {
  padding-top: 0;
}

.slide {
  height: 100vh;
  width: 100%;
  position: relative;
  background: #000;
  scroll-snap-align: start;
  scroll-snap-stop: always;
  user-select: none;
}

.media-container {
  position: relative;
  width: 100%;
  height: 100%;
}

.media {
  width: 100%;
  height: 100%;
  object-fit: contain;
  display: block;
}

#sentinel {
  height: 200px;
  width: 100%;
}