:root {
  --bg-dark: #111520;
  --card-dark: #282e37;
  --text-light: #f8fafc;
  --text-subtle: #94a3b8;
  --accent: #8b5cf6;
  --accent-hover: #7c3aed;
  --border: #334155;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
}

body {
  background: var(--bg-dark);
  color: var(--text-light);
  display: flex;
  flex-direction: column;
  align-items: center;
  min-height: 100vh;
}

header {
  color: var(--text-light);
  text-align: center;
  padding: 1rem 0;
}

header h1 {
  font-size: 1.5rem;
  font-weight: 500;
  letter-spacing: 1.25px;
}

header p {
  font-size: 1rem;
  font-weight: 400;
  color: var(--text-subtle);
  margin-top: 0.25rem;
}

main {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  justify-content: center;
  align-items: center;
}

#replayBtn {
  display: none;
  padding: 0.4rem 0.75rem;
  font-size: 1rem;
  font-weight: 600;
  border: none;
  border-radius: 12px;
  background: var(--accent);
  color: var(--bg-dark);
  cursor: pointer;
}
#replayBtn:hover {
  background: var(--accent-hover);
}

footer {
  margin-top: auto;
  margin-bottom: 0.5rem;
  font-size: 0.85rem;
  color: var(--text-subtle);
}
footer a {
  color: var(--text-subtle);
}

#msg {
  font-size: 1.25rem;
}

#grid {
  display: grid;
  grid-template-columns: repeat(4, 80px);
  grid-template-rows: repeat(4, 80px);
  gap: 0px;
  user-select: none;
  border: 1px solid var(--border);
  touch-action: none;
}

.cell {
  width: 80px;
  height: 80px;
  border: 1px solid var(--border);
  display: flex;
  justify-content: center;
  align-items: center;
  background-color: var(--card-dark);
}
.cell.over {
  background-color: var(--bg-dark);
}

.circle {
  width: 50px;
  height: 50px;
  border-radius: 50%;
  background-color: var(--accent);
  display: flex;
  justify-content: center;
  align-items: center;
  font-weight: bold;
  cursor: grab;
}
.circle.dragging {
  position: absolute; /* follow the pointer */
  z-index: 1000; /* above everything else */
  pointer-events: none; /* allow pointer detection on underlying cells */
  cursor: grabbing;
}

.ghost {
  width: 50px;
  height: 50px;
  border-radius: 50%;
  border: 2px dashed var(--border);
  background-color: var(--card-dark);
  position: absolute;
  display: flex;
  justify-content: center;
  align-items: center;
  font-weight: bold;
  color: var(--border);
  pointer-events: none;
}