:root {
  --bg: #0e0f13;
  --tile: #1b1d24;
  --ring: #7dd3fc;
  --ink: #e6e8ee;
  --muted: #8b90a0;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  height: 100%;
  background: var(--bg);
  color: var(--ink);
  font-family: system-ui, -apple-system, "Segoe UI", sans-serif;
  overflow: hidden;
}

#stage {
  position: fixed;
  inset: 0;
  overflow: hidden;
  touch-action: none;
  user-select: none;
}

#world {
  position: absolute;
  left: 0;
  top: 0;
  transform: translate(0, 0);
  transition: transform .5s cubic-bezier(.22, 1, .36, 1);
  will-change: transform;
}

.tile {
  position: absolute;
  border-radius: 6px;
  background: var(--tile);
  box-shadow: 0 2px 10px rgba(0, 0, 0, .45);
  cursor: pointer;
  transition: box-shadow .2s;
}
.tile img { width: 100%; height: 100%; object-fit: cover; display: block; border-radius: 6px; }
.tile.lock { animation: lock .5s cubic-bezier(.22, 1, .36, 1); }
.tile.ghost {
  opacity: .5;
  pointer-events: none;
  box-shadow: 0 0 0 2px rgba(125, 211, 252, .65);
}
.dropzone { position: absolute; }

@keyframes lock {
  0%   { transform: scale(.2); opacity: 0; }
  100% { transform: scale(1); opacity: 1; }
}

.tile.current {
  box-shadow: 0 0 0 2px var(--ring), 0 0 26px 2px rgba(125, 211, 252, .4);
}

.nav {
  position: absolute;
  inset: 0;
  pointer-events: none;
}

.nav-zone {
  position: absolute;
  pointer-events: auto;
}
.nav-zone-N { top: 0; left: 0; width: 100%; height: 26%; }
.nav-zone-S { bottom: 0; left: 0; width: 100%; height: 26%; }
.nav-zone-E { top: 26%; right: 0; width: 26%; height: 48%; }
.nav-zone-W { top: 26%; left: 0; width: 26%; height: 48%; }

.nav-btn {
  position: absolute;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  border: 1px solid rgba(255, 255, 255, .28);
  background: rgba(255, 255, 255, .1);
  color: rgba(255, 255, 255, .85);
  cursor: pointer;
  display: grid;
  place-items: center;
  box-shadow: 0 2px 12px rgba(0, 0, 0, .35);
  opacity: .18;
  transition: opacity .15s, background .15s, color .15s, box-shadow .15s;
}
.nav-btn svg { width: 18px; height: 18px; display: block; }
.nav-zone-N .nav-btn { top: 10px; left: 50%; translate: -50% 0; }
.nav-zone-E .nav-btn { top: 50%; right: 10px; translate: 0 -50%; }
.nav-zone-S .nav-btn { bottom: 10px; left: 50%; translate: -50% 0; }
.nav-zone-W .nav-btn { top: 50%; left: 10px; translate: 0 -50%; }
.nav-zone:hover .nav-btn {
  opacity: 1;
  background: rgba(255, 255, 255, .22);
  color: #fff;
  border-color: rgba(255, 255, 255, .5);
  box-shadow: 0 4px 18px rgba(0, 0, 0, .45);
}

#splash {
  position: fixed;
  inset: 0;
  display: grid;
  place-content: center;
  justify-items: center;
  gap: 14px;
  text-align: center;
  background: var(--bg);
  z-index: 10;
  transition: opacity .4s, visibility .4s;
}
#splash.hide { opacity: 0; visibility: hidden; pointer-events: none; }
#splash h1 { margin: 0; font-size: 44px; font-weight: 300; letter-spacing: .18em; }
#splash h1 .dot { color: var(--ring); }
#splash p { max-width: 34ch; color: var(--muted); margin: 0; font-size: 15px; line-height: 1.6; }
#start {
  margin-top: 10px;
  padding: 10px 34px;
  font-size: 15px;
  letter-spacing: .12em;
  border: 1px solid rgba(255, 255, 255, .3);
  border-radius: 999px;
  background: transparent;
  color: var(--ink);
  cursor: pointer;
  transition: border-color .15s, background .15s;
}
#start:hover { border-color: var(--ring); background: rgba(125, 211, 252, .08); }

@media (prefers-reduced-motion: reduce) {
  #world { transition: none; }
  .tile.lock { animation: none; }
}