* { box-sizing: border-box; }
body {
  margin: 0;
  min-height: 100vh;
  min-height: 100svh;
  padding: clamp(.75rem, 3vw, 1.5rem);
  background: linear-gradient(115deg, #086579, #701278);
  color: #fff;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: .75rem;
}
.menu, main { width: 100%; max-width: 40rem; }
h1 { margin: 0 0 .35rem; font-size: clamp(1.75rem, 7vw, 3rem); line-height: 1.1; }
p { margin: 0; line-height: 1.45; }
main { display: flex; flex-direction: column; align-items: center; gap: .65rem; }
.instructions { max-width: 36rem; }
.legend { font-size: .875rem; }
.status { min-height: 2.9em; font-weight: 650; max-width: 36rem; }
.board {
  width: min(90vw, 300px, 100%);
  aspect-ratio: 1;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  grid-template-rows: repeat(3, minmax(0, 1fr));
  flex: none;
}
button { font: inherit; }
.cell {
  position: relative;
  min-width: 0;
  min-height: 0;
  padding: 0;
  border: 0;
  border-right: 2px solid white;
  border-bottom: 2px solid white;
  background: transparent;
  color: #fff;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 0;
}
.cell:nth-child(3n) { border-right: 0; }
.cell:nth-child(n+7) { border-bottom: 0; }
.cell[aria-disabled="true"] { cursor: not-allowed; }
.cell.winner { background: #fff3; box-shadow: inset 0 0 0 4px #ffdf70; }
button:focus-visible { outline: 3px solid #ffdf70; outline-offset: 4px; z-index: 1; }
.cell:focus-visible { outline-offset: -6px; background: #ffffff12; }
.cell.x::before, .cell.x::after {
  content: "";
  position: absolute;
  width: 75%;
  height: 10%;
  background: currentColor;
  border-radius: 2px;
}
.cell.x::before { transform: rotate(45deg); }
.cell.x::after { transform: rotate(-45deg); }
.cell.circle::before {
  content: "";
  position: absolute;
  width: 72%;
  aspect-ratio: 1;
  border: 7px solid currentColor;
  border-radius: 50%;
  background: transparent;
}
/* Previews use the same proportions as marks. No preview on touch-only devices. */
@media (hover: hover) {
  .board[data-game-over="false"] .cell[aria-disabled="false"]:hover { color: #ffffff80; }
  .board[data-turn="X"][data-game-over="false"] .cell[aria-disabled="false"]:hover::before,
  .board[data-turn="X"][data-game-over="false"] .cell[aria-disabled="false"]:hover::after {
    content: ""; position: absolute; width: 75%; height: 10%; background: currentColor; border-radius: 2px;
  }
  .board[data-turn="X"] .cell[aria-disabled="false"]:hover::before { transform: rotate(45deg); }
  .board[data-turn="X"] .cell[aria-disabled="false"]:hover::after { transform: rotate(-45deg); }
  .board[data-turn="O"][data-game-over="false"] .cell[aria-disabled="false"]:hover::before {
    content: ""; position: absolute; width: 72%; aspect-ratio: 1; border: 7px solid currentColor; border-radius: 50%; background: transparent;
  }
}
.action-button {
  min-height: 44px;
  padding: .6rem 1rem;
  border: 2px solid white;
  border-radius: .5rem;
  background: #fff;
  color: #442050;
  font-weight: 650;
  cursor: pointer;
  max-width: 100%;
}
.action-button:hover { background: #ffefb0; }
[hidden] { display: none !important; }
.result-panel { width: 100%; }
.result-text { font-size: clamp(1.5rem, 6vw, 2.5rem); margin: 0 0 .35rem; }
dialog {
  width: min(90vw, 26rem);
  max-height: 90svh;
  overflow: auto;
  padding: 1.25rem;
  border: 2px solid white;
  border-radius: .75rem;
  background: #442050;
  color: white;
}
dialog::backdrop { background: #000b; }
dialog h2 { margin: 0 0 .75rem; font-size: clamp(1.25rem, 5vw, 1.75rem); }
.dialog-actions { display: flex; flex-wrap: wrap; justify-content: center; gap: .75rem; margin-top: 1rem; }
@media (forced-colors: active) {
  .cell.x::before, .cell.x::after { background: ButtonText; }
  .cell.circle::before { border-color: ButtonText; }
  .cell.winner { outline: 4px double Highlight; outline-offset: -4px; }
}