/* ---------- base ---------- */
:root {
  --ink: #e9eefc;
  --ink-dim: #8e9bc0;
  --void: #04060d;
  --edge: rgba(233, 238, 252, 0.16);
  --panel-pad: clamp(1.25rem, 5vw, 4rem);
}

* { box-sizing: border-box; }

html {
  height: 100%;
  scroll-behavior: smooth;
  scroll-snap-type: y mandatory;
  background: var(--void);
}

body {
  margin: 0;
  min-height: 100%;
  color: var(--ink);
  background: var(--void);
  font-family: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto,
               "Helvetica Neue", "Apple SD Gothic Neo", "Noto Sans KR", sans-serif;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

/* ---------- sky background ---------- */
.sky {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  overflow: hidden;
  background:
    radial-gradient(120% 90% at 50% 8%, #0b1024 0%, #06080f 46%, var(--void) 100%);
}

.sky__apod {
  position: absolute;
  inset: -8%;
  background-position: center;
  background-size: cover;
  background-repeat: no-repeat;
  opacity: 0;
  filter: saturate(1.15) contrast(1.05) blur(1px);
  transition: opacity 1.6s ease;
  will-change: transform;
}
.sky__apod.is-ready { opacity: 0.34; }

.sky__canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
}

/* transparent drag surface, sits above the sky but below the content */
.sky__grab {
  position: fixed;
  inset: 0;
  z-index: 1;
  border: 0;
  padding: 0;
  background: transparent;
  cursor: grab;
  touch-action: pan-y;          /* vertical touch still scrolls the page */
  -webkit-tap-highlight-color: transparent;
}
.sky__grab:focus-visible { outline: 2px solid var(--edge); outline-offset: -4px; }
.sky__grab.is-dragging { cursor: grabbing; }

.sky__hint,
.sky__readout {
  position: fixed;
  z-index: 3;
  margin: 0;
  font-size: 0.74rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-dim);
  pointer-events: none;
  transition: opacity 0.6s ease;
}
.sky__hint {
  left: var(--panel-pad);
  bottom: calc(var(--panel-pad) * 0.75);
}
.sky__readout {
  right: var(--panel-pad);
  bottom: calc(var(--panel-pad) * 0.75);
  font-variant-numeric: tabular-nums;
  text-transform: none;   /* uppercase would turn the alpha/delta glyphs into A/D */
  letter-spacing: 0.08em;
  opacity: 0.55;
}
.is-hidden { opacity: 0 !important; }

/* ---------- panels ---------- */
main {
  position: relative;
  z-index: 2;
  pointer-events: none;   /* the drag surface underneath must stay reachable */
}

.panel {
  position: relative;
  min-height: 100vh;
  min-height: 100svh;
  scroll-snap-align: start;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: clamp(1rem, 3vh, 2rem);
  padding: var(--panel-pad);
  pointer-events: none;          /* let drags fall through to the sky */
}
/* only genuinely interactive things swallow the pointer, so a drag that
   starts on top of the headline still pans the sky */
.scroll-cue,
.player,
.player__bar { pointer-events: auto; }

/* ---------- hero ---------- */
.hero__title {
  margin: 0;
  max-width: 18ch;
  text-align: center;
  font-size: clamp(1.9rem, 6.2vw, 4.4rem);
  font-weight: 300;
  line-height: 1.16;
  letter-spacing: -0.02em;
  text-wrap: balance;
  text-shadow: 0 0 40px rgba(4, 6, 13, 0.85), 0 2px 18px rgba(4, 6, 13, 0.9);
}

.hero__sub {
  margin: 0;
  font-size: 0.78rem;
  letter-spacing: 0.4em;
  text-transform: uppercase;
  color: var(--ink-dim);
}

.scroll-cue {
  position: absolute;
  left: 50%;
  bottom: clamp(1.5rem, 5vh, 3rem);
  transform: translateX(-50%);
  display: grid;
  justify-items: center;
  gap: 0.6rem;
  color: var(--ink-dim);
  text-decoration: none;
  font-size: 0.68rem;
  letter-spacing: 0.3em;
  text-transform: uppercase;
}
.scroll-cue:hover, .scroll-cue:focus-visible { color: var(--ink); }
.scroll-cue__arrow {
  width: 9px;
  height: 9px;
  border-right: 1px solid currentColor;
  border-bottom: 1px solid currentColor;
  transform: rotate(45deg);
  animation: nudge 2.4s ease-in-out infinite;
}
@keyframes nudge {
  0%, 100% { transform: rotate(45deg) translate(0, 0); opacity: 0.45; }
  50%      { transform: rotate(45deg) translate(3px, 3px); opacity: 1; }
}

/* ---------- video ---------- */
.player {
  position: relative;
  width: min(100%, 1100px, max(16rem, (100svh - 17rem) * 16 / 9));
  aspect-ratio: 16 / 9;
  flex: 0 0 auto;
  border-radius: 14px;
  overflow: hidden;
  background: #000;
  border: 1px solid var(--edge);
  box-shadow: 0 30px 80px rgba(0, 0, 0, 0.6);
}
.player iframe,
.player .facade {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  border: 0;
}

.facade {
  padding: 0;
  background: #000;
  cursor: pointer;
  display: grid;
  place-items: center;
}
.facade__thumb {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.85;
}
.facade__play {
  position: relative;
  width: 74px;
  height: 52px;
  border-radius: 12px;
  background: rgba(10, 12, 20, 0.72);
  border: 1px solid var(--edge);
  backdrop-filter: blur(6px);
  transition: background 0.2s ease, transform 0.2s ease;
}
.facade__play::after {
  content: "";
  position: absolute;
  top: 50%;
  left: 52%;
  transform: translate(-50%, -50%);
  border-style: solid;
  border-width: 9px 0 9px 15px;
  border-color: transparent transparent transparent var(--ink);
}
.facade:hover .facade__play { background: rgba(30, 36, 56, 0.85); transform: scale(1.06); }

.player__bar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  justify-content: center;
}

.btn {
  font: inherit;
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  color: var(--ink);
  background: rgba(16, 20, 34, 0.7);
  border: 1px solid var(--edge);
  border-radius: 999px;
  padding: 0.55rem 1.1rem;
  cursor: pointer;
  text-decoration: none;
  transition: background 0.2s ease, border-color 0.2s ease;
}
.btn:hover, .btn:focus-visible { background: rgba(36, 42, 64, 0.85); border-color: rgba(233, 238, 252, 0.35); }
.btn--ghost { background: transparent; color: var(--ink-dim); }

.attribution {
  margin: 0;
  max-width: 62ch;
  text-align: center;
  text-wrap: balance;
  font-size: 0.66rem;
  line-height: 1.75;
  letter-spacing: 0.04em;
  color: var(--ink-dim);
  opacity: 0.8;
}
.attribution em { font-style: italic; }

/* ---------- credits ---------- */
.credits {
  position: fixed;
  z-index: 3;
  top: calc(var(--panel-pad) * 0.7);
  right: var(--panel-pad);
  display: grid;
  justify-items: end;
  gap: 0.3em;
  font-size: 0.66rem;
  letter-spacing: 0.1em;
  color: var(--ink-dim);
  text-align: right;
  max-width: min(46ch, 50vw);
  pointer-events: none;
}
.credits__apod { opacity: 0.75; text-transform: none; letter-spacing: 0.02em; }

@media (max-width: 640px) {
  .credits { max-width: 60vw; font-size: 0.6rem; }
  .sky__readout { display: none; }

  /* keep the hint clear of the scroll cue on narrow screens */
  .sky__hint {
    left: 50%;
    right: auto;
    transform: translateX(-50%);
    bottom: calc(var(--panel-pad) * 0.75 + 5.2rem);
    text-align: center;
  }
  .attribution { font-size: 0.6rem; line-height: 1.7; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .scroll-cue__arrow { animation: none; }
  .sky__apod { transition: none; }
}