* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "Segoe UI", sans-serif;
}

body {
  height: 100vh;
  background: linear-gradient(135deg, #1f2933, #111827);
  display: flex;
  justify-content: center;
  align-items: center;
  color: white;
}

.container {
  width: 320px;
}

.card {
  background: rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(10px);
  border-radius: 16px;
  padding: 25px;
  text-align: center;
  box-shadow: 0 15px 30px rgba(0,0,0,0.4);
}

h1 {
  margin-bottom: 20px;
}

h2 {
  margin-bottom: 15px;
}

button {
  width: 100%;
  padding: 12px;
  margin: 10px 0;
  border: none;
  border-radius: 10px;
  background: #22c55e;
  color: black;
  font-size: 16px;
  cursor: pointer;
  transition: 0.3s;
}

button:hover {
  background: #16a34a;
}

.board {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
  margin: 20px 0;
}

.cell {
  height: 80px;
  background: rgba(255, 255, 255, 0.15);
  border-radius: 10px;
  font-size: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: 0.2s;
}

.cell:hover {
  background: rgba(255, 255, 255, 0.3);
}

.restart {
  background: #38bdf8;
}

.restart:hover {
  background: #0ea5e9;
}

.hidden {
  display: none;
}