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

:root {
  --cell-size: 100px;
  --mark-size: calc(var(--cell-size) * 0.7);
}

body {
  background-color: #001e3c;
}

.container {
  padding-top: 30px;
  height: 100vh;
  width: 100vw;
  display: flex;
  flex-direction: column;

  justify-content: start;
  align-items: center;
}

.title {
  color: #00ffff;
  font-size: 4rem;
  text-align: center;
  margin-bottom: 20px;
}

.board {
  display: grid;
  justify-content: center;
  grid-template-columns: repeat(3, auto);
  justify-items: center;
  align-items: center;
}

.cell {
  width: var(--cell-size);
  height: var(--cell-size);
  border: 1.5px solid #00ffff;

  display: flex;
  justify-content: center;
  align-items: center;

  position: relative;

  cursor: pointer;
}

.cell:first-child,
.cell:nth-child(2),
.cell:nth-child(3) {
  border-top: none;
}

.cell:nth-child(3n + 1) {
  border-left: none;
}

.cell:nth-child(3n + 3) {
  border-right: none;
}

.cell:last-child,
.cell:nth-child(8),
.cell:nth-child(7) {
  border-bottom: none;
}

.cell.x,
.cell.circle {
  cursor: not-allowed;
}

.cell.x::before,
.cell.x::after {
  background-color: #7a0cd3;
}

.cell.circle::before,
.cell.circle::after {
  background-color: #56baed;
}

.board.x .cell:not(.x):not(.circle):hover::before,
.board.x .cell:not(.x):not(.circle):hover::after,
.board.circle .cell:not(.x):not(.circle):hover::before,
.board.circle .cell:not(.x):not(.circle):hover::after {
  background-color: #999;
}

.cell.x::before,
.cell.x::after,
.board.x .cell:not(.x):not(.circle):hover::before,
.board.x .cell:not(.x):not(.circle):hover::after {
  content: '';
  position: absolute;
  width: calc(var(--mark-size) * 0.15);
  height: var(--mark-size);
  border-radius: 4px;
}

.cell.x::before,
.board.x .cell:not(.x):not(.circle):hover::before {
  transform: rotate(45deg);
}

.cell.x::after,
.board.x .cell:not(.x):not(.circle):hover::after {
  transform: rotate(-45deg);
}

.cell.circle::before,
.cell.circle::after,
.board.circle .cell:not(.x):not(.circle):hover::before,
.board.circle .cell:not(.x):not(.circle):hover::after {
  content: '';
  position: absolute;
  border-radius: 50%;
}
.cell.circle::before,
.board.circle .cell:not(.x):not(.circle):hover::before {
  width: var(--mark-size);
  height: var(--mark-size);
}

.cell.circle::after,
.board.circle .cell:not(.x):not(.circle):hover::after {
  width: calc(var(--mark-size) * 0.7);
  height: calc(var(--mark-size) * 0.7);
  background-color: #001e3c;
}

.winning-message {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: rgba(0, 0, 0, 0.9);
  justify-content: center;
  align-items: center;
  font-size: 2rem;
  color: white;
  flex-direction: column;
}

.winning-message button {
  font-size: 2rem;
  background-color: cadetblue;
  color: #001e3c;
  border: 2px solid #00ffff;
  padding: 0.25em 0.5em;
  cursor: pointer;
}

.winning-message button:hover {
  background-color: #eee;
}

.winning-message button:active {
  transform: translateY(10px);
}

.turning-message {
  text-align: center;
  color: #eee;
  font-size: 2rem;
  margin-bottom: 20px;
}

.winning-message.show {
  display: flex;
}