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

/* Dark theme (default) */
:root {
  color-scheme: dark light;
  --bg: #000;
  --fg: #fff;
  --muted: #a3a3a3;
  --rule: rgba(255, 255, 255, 0.5);
  --panel-bg: rgba(0, 0, 0, 0.8);
  --panel-border: rgba(255, 255, 255, 0.1);
  --title-glow: rgba(255, 255, 255, 0.25);
  --grain-opacity: 0.09;
  --vignette: rgba(0, 0, 0, 0.75);
}

/* Light theme */
@media (prefers-color-scheme: light) {
  :root {
    --bg: #fff;
    --fg: #000;
    --muted: #5c5c5c;
    --rule: rgba(0, 0, 0, 0.55);
    --panel-bg: rgba(255, 255, 255, 0.85);
    --panel-border: rgba(0, 0, 0, 0.1);
    --title-glow: rgba(0, 0, 0, 0.15);
    --grain-opacity: 0.12;
    --vignette: rgba(0, 0, 0, 0.18);
  }
}

html,
body {
  min-height: 100%;
  background: var(--bg);
  color: var(--fg);
  font-family: "Segoe UI", system-ui, -apple-system, Roboto, "Helvetica Neue", Arial, sans-serif;
  line-height: 1.75;
  overflow-x: hidden;
}

/* ---------- Loader ---------- */
#loader {
  position: fixed;
  inset: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg);
  transition: opacity 1.1s ease, visibility 1.1s ease;
}

#loader.hidden {
  opacity: 0;
  visibility: hidden;
}

#rings {
  width: min(300px, 65vw);
  height: min(300px, 65vw);
}

/* ---------- Galaxy ---------- */
#galaxy {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  z-index: 0;
  opacity: 0;
  transition: opacity 2.5s ease;
}

#galaxy.visible {
  opacity: 1;
}

html,
body {
  height: 100%;
  overflow: hidden;
}

/* The only scrolling element. Its scrollbar space is always reserved, so locking/unlocking
   never changes the layout width — no horizontal shift, no canvas stretch. */
#scroller {
  position: fixed;
  inset: 0;
  z-index: 1;
  overflow-x: hidden;
  overflow-y: auto;
  scrollbar-gutter: stable both-edges;
  overscroll-behavior: contain;
}

#scroller.locked {
  overflow-y: hidden;
}

/* Invisible circular hit area over the black hole */
#enter {
  position: fixed;
  left: 50%;
  top: 50%;
  z-index: 60;
  width: var(--hole, 120px);
  height: var(--hole, 120px);
  transform: translate(-50%, -50%);
  border: 0;
  border-radius: 50%;
  background: transparent;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}

#enter:focus {
  outline: none;
}

#enter:focus-visible {
  outline: 1px solid var(--rule);
  outline-offset: 4px;
}

#enter[hidden] {
  display: none;
}

/* ---------- Film grain & vignette ---------- */
#grain,
#vignette {
  position: fixed;
  pointer-events: none;
}

#grain {
  inset: -50%;
  z-index: 50;
  opacity: var(--grain-opacity);
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='220' height='220'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='3' stitchTiles='stitch'/%3E%3CfeColorMatrix values='0 0 0 0 0.5 0 0 0 0 0.5 0 0 0 0 0.5 0 0 0 1.6 -0.3'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
  animation: grain 0.9s steps(6) infinite;
}

@keyframes grain {
  0% { transform: translate(0, 0); }
  20% { transform: translate(-3%, 2%); }
  40% { transform: translate(2%, -4%); }
  60% { transform: translate(-4%, -1%); }
  80% { transform: translate(3%, 3%); }
  100% { transform: translate(0, 0); }
}

#vignette {
  inset: 0;
  z-index: 49;
  background: radial-gradient(ellipse at center, transparent 55%, var(--vignette) 100%);
}

/* ---------- Content ---------- */
#content {
  position: relative;
  z-index: 1;
  max-width: 760px;
  margin: 0 auto;
  padding: 14vh 1.5rem 6rem;
}

#title {
  text-align: center;
  margin-bottom: 3.5rem;
}

.title-main {
  font-size: clamp(4rem, 16vw, 9rem);
  font-weight: 900;
  letter-spacing: 0.08em;
  margin-right: -0.08em; /* optically center the tracked letters */
  line-height: 1;
  color: var(--fg);
  text-shadow: 0 0 30px var(--title-glow);
}

.rule {
  width: min(340px, 60%);
  margin: 1.4rem auto 1rem;
  border-top: 1px solid var(--rule);
}

.title-sub {
  font-size: clamp(0.9rem, 3vw, 1.3rem);
  font-weight: 300;
  letter-spacing: 0.6em;
  margin-right: -0.6em;
  text-transform: uppercase;
  color: var(--muted);
}

.panel {
  padding: clamp(1.25rem, 4vw, 2rem) clamp(1.25rem, 4vw, 2.25rem);
  background: var(--panel-bg);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border: 1px solid var(--panel-border);
  border-radius: 14px;
}

.panel + .panel {
  margin-top: 1.5rem;
}

.panel p {
  font-size: clamp(1rem, 2.4vw, 1.15rem);
}

.panel p + p {
  margin-top: 1.25rem;
}

#description em {
  font-style: normal;
  font-weight: 700;
}

#flag {
  display: flex;
  justify-content: center;
  margin-top: 3rem;
}

#flag img {
  display: block;
  width: min(110px, 28vw);
  height: auto;
}

/* ---------- Iterative reveal (slow, like an exposure developing) ---------- */
.reveal {
  opacity: 0;
  filter: blur(4px) contrast(0.6);
  transition: opacity 1.4s ease, filter 1.6s ease;
}

.reveal.shown {
  opacity: 1;
  filter: none;
}

@media (prefers-reduced-motion: reduce) {
  .reveal,
  #galaxy,
  #loader {
    transition: none;
  }
  #grain {
    animation: none;
  }
}