:root {
  --stage-w: 1920px;
  --stage-h: 1080px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html,
body {
  width: 100%;
  height: 100%;
  overflow: hidden;
  background: #0a0a0a;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

.viewport {
  width: 100vw;
  height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

/* Scales the fixed 1920×1080 stage to fit the viewport */
.stage-scaler {
  width: var(--stage-w);
  height: var(--stage-h);
  flex-shrink: 0;
  transform-origin: center center;
}

/* Fixed 1920×1080 stage — all slides and assets are authored at this size */
.presentation {
  position: relative;
  width: var(--stage-w);
  height: var(--stage-h);
  overflow: hidden;
  background: #111;
}

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

/* ── Slides ─────────────────────────────────────────────── */

.slide {
  position: absolute;
  inset: 0;
  width: var(--stage-w);
  height: var(--stage-h);
  visibility: hidden;
  opacity: 0;
}

.slide.is-active {
  visibility: visible;
}

.slide--image {
  background: #111;
}

.slide--image img {
  width: var(--stage-w);
  height: var(--stage-h);
  object-fit: contain;
  object-position: center;
  display: block;
  user-select: none;
  -webkit-user-drag: none;
}

.slide--video {
  background: #111;
}

.slide--video video {
  width: var(--stage-w);
  height: var(--stage-h);
  object-fit: contain;
  object-position: center;
  display: block;
  user-select: none;
  -webkit-user-drag: none;
}

.slide--interactive {
  color: #fff;
}

/* ── Slide counter ──────────────────────────────────────── */

.slide-counter {
  position: absolute;
  bottom: 32px;
  right: 40px;
  font-size: 18px;
  font-weight: 500;
  letter-spacing: 0.04em;
  color: rgba(255, 255, 255, 0.45);
  pointer-events: none;
  z-index: 100;
}

.slide-counter-sep {
  margin: 0 4px;
  opacity: 0.5;
}

/* ── Placeholder (when image is missing) ────────────────── */

.slide-placeholder {
  width: var(--stage-w);
  height: var(--stage-h);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 16px;
  background: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);
  color: rgba(255, 255, 255, 0.6);
  font-size: 24px;
}

.slide-placeholder small {
  font-size: 16px;
  opacity: 0.5;
}