:root {
  --bg-color: #0e0e11;
  --surface: rgba(255, 255, 255, 0.05);
  --frosted-glass: rgba(255, 255, 255, 0.08);
  --border-color: rgba(255, 255, 255, 0.12);
  --accent: #c3d0ff;
  --text-color: #e5e7eb;
  --font-family: "Inter", "Segoe UI", "Roboto", sans-serif;
}

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

body {
  display: flex;
  flex-direction: column;
  align-items: center;
  height: 100vh;
  background: radial-gradient(circle at top, #15161a 0%, #0e0e11 100%);
  color: var(--text-color);
  font-family: var(--font-family);
  text-align: center;
  letter-spacing: 0.5px;
  backdrop-filter: blur(10px);
  margin-top: 3em;
  gap: 1em;
}

h1 {
  font-size: 2.5rem;
  font-weight: 600;
  margin-bottom: 1rem;
  color: var(--accent);
}

h2 {
  font-size: 1rem;
  font-weight: 400;
  margin-bottom: 0.5rem;
  color: rgba(255, 255, 255, 0.8);
}

form > label {
  margin: 0 0.5rem;
  cursor: pointer;
  color: rgba(255, 255, 255, 0.7);
  transition: 0.3s ease;
}

form > input[type="radio"] {
  margin-right: 1rem;
  accent-color: var(--accent);
  cursor: pointer;
}

form > label:hover {
  color: var(--accent);
}

#game-grid {
  display: grid;
  grid-template: repeat(3, 1fr) / repeat(3, 1fr);
  gap: 8px;
  margin: 2rem 0;
  padding: 10px;
  background: var(--surface);
  border-radius: 16px;
  border: 1px solid var(--border-color);
  box-shadow: 0 4px 30px rgba(0, 0, 0, 0.2);
  backdrop-filter: blur(20px);
  place-items: center;
  aspect-ratio: 1/1;
}

.game-grid-item {
  display: flex;
  justify-content: center;
  align-items: center;
  background: var(--frosted-glass);
  border: 1px solid var(--border-color);
  height: 130px;
  width: 130px;
  font-size: 3.5rem;
  font-weight: 600;
  color: var(--text-color);
  transition: all 0.2s ease-in-out;
  border-radius: 12px;
  backdrop-filter: blur(10px);
}

.game-grid-item:hover {
  background: rgba(255, 255, 255, 0.1);
  transform: translateY(-2px);
  cursor: pointer;
}

.game-grid-item.winning-line {
  background: blue;
}


#game-button {
  background: var(--surface);
  border: 1px solid var(--border-color);
  color: var(--text-color);
  font-family: var(--font-family);
  padding: 0.7rem 2rem;
  font-size: 1rem;
  border-radius: 12px;
  transition: all 0.3s ease;
  text-transform: uppercase;
  letter-spacing: 2px;
}

#game-button:hover {
  background: rgba(255, 255, 255, 0.15);
  color: var(--accent);
  transform: translateY(-1px);
  cursor: pointer;
}

@media (max-width: 500px) {
  .game-grid-item {
    height: 90px;
    width: 90px;
    font-size: 2.2rem;
  }

  h1 {
    font-size: 2rem;
  }
}