:root {
  color-scheme: dark;
  --header-height: 82px;
  --background: #151b24;
  --surface: #202b39;
  --surface-hover: #29384a;
  --text: #edf1f3;
  --muted: #aeb9c2;
  --accent: #91aed0;
  --accent-soft: #7896bb;
  --flax-green: #75887b;
  --fiber-gray: #9ca3a6;
}

* { box-sizing: border-box; }

html, body {
  min-height: 100%;
  margin: 0;
  background: var(--background);
  color: var(--text);
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

button { font: inherit; }

.site-header {
  position: fixed;
  inset: 0 0 auto;
  z-index: 20;
  min-height: var(--header-height);
  padding: 14px max(18px, env(safe-area-inset-right)) 12px max(18px, env(safe-area-inset-left));
  display: flex;
  align-items: center;
  gap: 22px;
  background: rgba(25, 34, 46, .95);
  border-bottom: 1px solid rgba(145, 174, 208, .22);
  box-shadow: 0 8px 28px rgba(4, 10, 18, .22);
  backdrop-filter: blur(12px);
}

.home-button {
  flex: 0 0 auto;
  border: 0;
  padding: 0;
  color: #a9c1de;
  background: none;
  font-weight: 750;
  cursor: pointer;
}

.site-header h1 {
  min-width: 0;
  margin: 0;
  overflow: hidden;
  color: var(--text);
  font-size: clamp(1rem, 2.2vw, 1.35rem);
  font-weight: 600;
  line-height: 1.25;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.catalog {
  width: min(1480px, 100%);
  margin: 0 auto;
  padding: calc(var(--header-height) + 32px) 24px 48px;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  gap: 22px;
}

.presentation-card {
  overflow: hidden;
  border: 1px solid rgba(145, 174, 208, .16);
  border-radius: 14px;
  padding: 0;
  color: var(--text);
  background: var(--surface);
  text-align: left;
  cursor: pointer;
  transition: transform .16s ease, background .16s ease;
}

.presentation-card:hover,
.presentation-card:focus-visible {
  transform: translateY(-3px);
  background: var(--surface-hover);
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.presentation-card img {
  display: block;
  width: 100%;
  aspect-ratio: 16 / 10;
  object-fit: contain;
  background: #111820;
}

.card-text { display: block; padding: 15px 16px 17px; }
.card-title { display: block; font-size: 1rem; font-weight: 650; line-height: 1.35; }
.card-count { display: block; margin-top: 7px; color: var(--fiber-gray); font-size: .88rem; }
.loading, .error { grid-column: 1 / -1; padding: 52px 10px; color: var(--muted); text-align: center; }

.viewer {
  position: fixed;
  inset: var(--header-height) 0 0;
  display: grid;
  grid-template-rows: minmax(0, 1fr) auto;
  background: #0e141c;
  touch-action: pan-y;
}

.viewer[hidden] { display: none; }

.viewer-stage {
  position: relative;
  min-width: 0;
  min-height: 0;
  overflow: hidden;
}

.slide {
  position: absolute;
  inset: 0;
  margin: 0;
  overflow: hidden;
}

.slide img {
  position: absolute;
  inset: 0;
  display: block;
  width: 100%;
  height: 100%;
  object-fit: contain;
  object-position: center center;
  user-select: none;
  -webkit-user-drag: none;
}

.nav-button {
  position: absolute;
  z-index: 10;
  top: 0;
  bottom: 0;
  width: min(14vw, 130px);
  border: 0;
  color: white;
  background: transparent;
  font-size: clamp(3rem, 7vw, 6rem);
  opacity: .45;
  cursor: pointer;
  transition: opacity .15s, background .15s;
}

.nav-button:hover, .nav-button:focus-visible { opacity: 1; background: rgba(0, 0, 0, .24); outline: 0; }
.nav-button:disabled { opacity: .1; cursor: default; }
.nav-button--previous { left: 0; }
.nav-button--next { right: 0; }

.viewer-controls {
  position: relative;
  min-height: 58px;
  padding: 8px max(14px, env(safe-area-inset-right)) calc(8px + env(safe-area-inset-bottom)) max(14px, env(safe-area-inset-left));
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 12px;
  background: rgba(27, 37, 49, .97);
}

.viewer-controls button {
  width: max-content;
  border: 1px solid rgba(255, 255, 255, .2);
  border-radius: 8px;
  padding: 8px 12px;
  color: var(--text);
  background: var(--surface);
  cursor: pointer;
}

.viewer-controls button:last-child { justify-self: end; }
#slideCounter { color: var(--muted); font-variant-numeric: tabular-nums; }

@media (max-width: 700px) {
  :root { --header-height: 94px; }
  .site-header { display: block; padding-top: 11px; }
  .site-header h1 { margin-top: 7px; }
  .catalog { grid-template-columns: 1fr 1fr; gap: 12px; padding: calc(var(--header-height) + 16px) 12px 28px; }
  .card-text { padding: 11px 12px 13px; }
  .card-title { font-size: .9rem; }
  .nav-button { width: 18vw; font-size: 3.5rem; }
  .viewer-controls { grid-template-columns: 1fr auto 1fr; gap: 6px; font-size: .8rem; }
  .viewer-controls button { padding: 8px; }
}

@media (max-width: 430px) {
  .catalog { grid-template-columns: 1fr; }
}