* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background: linear-gradient(to right, #00c6ff, #0072ff);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  color: #fff;
}

/* Start Screen */
.start-screen {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

.symbol-buttons {
  display: flex;
  gap: 20px;
  margin-top: 20px;
}

.choose-btn {
  padding: 15px 30px;
  font-size: 1.5rem;
  background: #fff;
  color: #0072ff;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  transition: background-color 0.3s;
}

.choose-btn:hover {
  background-color: #f0f0f0;
}

/* Game UI */
h1 {
  margin-bottom: 20px;
  font-size: 2rem;
}

.game-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  z-index: 1;
}

.board {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 5px;
  width: 90vmin;
  max-width: 300px;
  aspect-ratio: 1 / 1;
  margin-bottom: 20px;
}

.cell {
  background-color: #fff;
  border: 2px solid #333;
  font-size: 3rem;
  color: #333;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  user-select: none;
  transition: background-color 0.3s;
}

.cell:hover {
  background-color: #eee;
}

.status {
  font-size: 1.5rem;
  margin-bottom: 10px;
  text-align: center;
  color: #fff;
}

.restart-btn,
.new-game-btn {
  padding: 10px 20px;
  font-size: 1rem;
  border: none;
  background-color: #ffffff;
  color: #0072ff;
  font-weight: bold;
  border-radius: 5px;
  cursor: pointer;
  transition: background-color 0.3s;
}

.restart-btn:hover,
.new-game-btn:hover {
  background-color: #f0f0f0;
}

/* End Screen */
.end-screen {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: rgba(0, 0, 0, 0.85);
  color: #fff;
  display: none;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  z-index: 10;
}

.result-text {
  font-size: 2rem;
  margin-bottom: 20px;
}