/* ═══════════════════════════════════════════════════════════════════
   Deck Shell — base layout, themes, transitions, navigation
   ═══════════════════════════════════════════════════════════════════ */

/* ─── Reset ─── */
*,
*::before,
*::after {
  box-sizing: border-box;
}

html,
body {
  width: 100%;
  height: 100%;
  margin: 0;
}

body {
  font-family: var(--font-body);
  background: radial-gradient(circle at top, #0f1730 5%, #060712 70%);
  color: var(--color-text);
  display: grid;
  place-items: center;
  overflow: hidden;
}

/* ─── Deck Container ─── */
.deck {
  width: var(--slide-width);
  height: var(--slide-height);
  position: relative;
  border-radius: var(--radius-base);
  overflow: hidden;
  box-shadow: 0 20px 90px rgba(0, 0, 0, 0.45);
  container-type: inline-size;
}

/* ─── Slide Base ─── */
.slide {
  position: absolute;
  inset: 0;
  padding: var(--space-layout);
  display: grid;
  grid-template-rows: auto 1fr;
  opacity: 0;
  transform: translateX(3%);
  transition: opacity 420ms ease, transform 420ms ease;
  pointer-events: none;
}

.slide.active {
  opacity: 1;
  transform: translateX(0);
  pointer-events: auto;
}

/* ─── Theme: Dark ─── */
.slide.dark {
  background: linear-gradient(145deg, var(--color-bg), #030316 72%);
  color: var(--color-text);
}

/* ─── Theme: Light ─── */
.slide.light {
  background: linear-gradient(145deg, var(--color-bg-surface), var(--color-bg-surface-alt));
  color: var(--color-text-inverse);
}

/* ─── Build-Step Animation ─── */
[data-step] {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity 380ms ease, transform 380ms ease;
}

.is-visible {
  opacity: 1;
  transform: translateY(0);
}

.build-in {
  animation: riseIn 380ms ease;
}

@keyframes riseIn {
  from {
    opacity: 0;
    transform: translateY(12px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ─── Progress Bar ─── */
.deck-progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 3px;
  background: color-mix(in srgb, #fff, transparent 90%);
  z-index: 20;
}

.deck-progress > span {
  display: block;
  width: 0%;
  height: 100%;
  background: color-mix(in srgb, var(--color-accent), #fff 25%);
  transition: width 300ms ease;
}

/* ─── Navigation Controls ─── */
.controls {
  position: fixed;
  right: 1.1rem;
  bottom: 1.1rem;
  display: flex;
  gap: 0.5rem;
  z-index: 40;
}

.btn {
  appearance: none;
  border: 1px solid rgba(255, 255, 255, 0.2);
  background: rgba(8, 8, 36, 0.72);
  color: var(--color-text);
  padding: 0.5rem 0.75rem;
  border-radius: 0.6rem;
  font: 600 0.84rem / var(--line-height-reset) var(--font-body);
  cursor: pointer;
}

/* ─── Responsive ─── */
@media (max-aspect-ratio: 16/10) {
  .slide-content {
    max-width: 96%;
  }

  .slide-cards--5col {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}