@view-transition {
  navigation: auto;
}

@keyframes flip-out {
  0% {
    transform: perspective(1100px) rotateY(0deg);
    opacity: 1;
  }

  100% {
    transform: perspective(1100px) rotateY(-90deg);
    opacity: 0;
  }
}

@keyframes flip-in {
  0% {
    transform: perspective(1100px) rotateY(90deg);
    opacity: 0;
  }

  100% {
    transform: perspective(1100px) rotateY(0deg);
    opacity: 1;
  }
}

::view-transition-old(root) {
  animation: flip-out 0.3s cubic-bezier(0.4, 0, 1, 1) forwards;
  transform-origin: center center;
}

::view-transition-new(root) {
  animation: flip-in 0.3s cubic-bezier(0, 0, 0.6, 1) 0.3s backwards;
  transform-origin: center center;
}

/* ── Reset & base ── */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --bg: oklch(12% 0.04 340);
  --surface: oklch(16% 0.05 340);
  --accent: oklch(74% 0.19 15);
  --text: oklch(93% 0.02 30);
  --muted: oklch(55% 0.03 340);
}

html,
body {
  height: 100%;
  font-family: 'Outfit', sans-serif;
}

body {
  min-height: 100dvh;
  background: var(--bg);
  color: var(--text);
  display: grid;
  grid-template-columns: 1fr 1fr;
perspective: 1100px;
  /* grain overlay */
  &::after {
    content: '';
    position: fixed;
    inset: 0;
    background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.75' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.035'/%3E%3C/svg%3E");
    background-size: 180px;
    pointer-events: none;
    z-index: 100;
  }
}

/* ── Image panel ── */
.panel-img {
  position: relative;
  overflow: hidden;

  img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
    filter: saturate(0.75) contrast(1.05);
  }

  &::after {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(to right, transparent 60%, var(--bg) 100%);
  }
}

/* ── Text panel ── */
.panel-text {
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 5rem 4rem 5rem 3rem;
  gap: 2rem;
}

.chapter {
  font-size: 0.6rem;
  letter-spacing: 0.4em;
  text-transform: uppercase;
  color: var(--accent);
}

h1 {
  font-family: 'Cormorant Garamond', serif;
  font-size: clamp(2.8rem, 4.5vw, 5rem);
  font-weight: 600;
  line-height: 1.05;

  em {
    font-style: italic;
    font-weight: 300;
    color: oklch(85% 0.06 30);
  }
}

p {
  font-weight: 200;
  font-size: 0.95rem;
  line-height: 1.85;
  color: var(--muted);
  max-width: 34ch;
}

/* ── Navigation ── */
nav {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  margin-top: 1rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-family: 'Outfit', sans-serif;
  font-size: 0.72rem;
  font-weight: 400;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  text-decoration: none;
  color: var(--bg);
  background: var(--accent);
  border-radius: 100vmax;
  padding: 0.8rem 2rem;
  transition: background 0.2s, transform 0.15s;

  &:hover {
    background: oklch(82% 0.15 15);
  }

  &:active {
    transform: scale(0.97);
  }
}

.pips {
  display: flex;
  gap: 0.45rem;
  align-items: center;
}

.pip {
  width: 0.3rem;
  height: 0.3rem;
  border-radius: 50%;
  background: var(--muted);

  &.active {
    background: var(--accent);
    transform: scale(1.5);
  }
}

/* ── Decorative page number ── */
.bg-num {
  position: fixed;
  bottom: -1rem;
  right: 2rem;
  font-family: 'Cormorant Garamond', serif;
  font-size: 14rem;
  font-weight: 600;
  color: oklch(100% 0 0 / 0.025);
  line-height: 1;
  pointer-events: none;
  user-select: none;
}

@media (max-width: 700px) {
  body {
    grid-template-columns: 1fr;
    grid-template-rows: 40dvh 1fr;
  }

  .panel-img::after {
    background: linear-gradient(to bottom, transparent 60%, var(--bg) 100%);
  }

  .panel-text {
    padding: 2.5rem 1.75rem;
  }
}