:root {
  --bg: #0b0f14;
  --ink: #f4f7fb;
  --muted: #9aa7b5;
  --accent: #2bb673;
  --font: "Source Sans 3", "Segoe UI", sans-serif;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  width: 100%;
  height: 100%;
  background: #000;
  color: var(--ink);
  font-family: var(--font);
  overflow: hidden;
}

.stage {
  position: fixed;
  inset: 0;
  display: grid;
  place-items: center;
  background: #000;
}

/* Lock the presentation frame to 16:9 within the viewport */
.stage::before {
  content: "";
  grid-area: 1 / 1;
  width: min(100vw, calc(100vh * 16 / 9));
  height: min(100vh, calc(100vw * 9 / 16));
}

.slide {
  grid-area: 1 / 1;
  width: min(100vw, calc(100vh * 16 / 9));
  height: min(100vh, calc(100vw * 9 / 16));
  object-fit: fill;
  background: #000;
  opacity: 0;
  transition: opacity 0.55s ease;
  pointer-events: none;
}

.slide.active {
  opacity: 1;
}

.empty {
  height: 100vh;
  display: grid;
  place-items: center;
  text-align: center;
  padding: 2rem;
  background:
    radial-gradient(circle at top, rgba(43, 182, 115, 0.18), transparent 40%),
    linear-gradient(180deg, #101820, #0b0f14 70%);
}

.empty h1 {
  margin: 0 0 0.5rem;
  font-size: clamp(1.6rem, 3vw, 2.4rem);
  letter-spacing: -0.03em;
}

.empty p {
  margin: 0;
  color: var(--muted);
  max-width: 28rem;
}