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

body {
  font-family: Arial, sans-serif;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  height: 100vh;
  background-color: #000000;
  color: #fff;
  text-align: center;
}

@media (max-width: 600px) {
  nav {
    flex-wrap: wrap; 
    padding: 8px; 
  }

  .nav-links {
    display: flex; 
    flex-direction: row; 
    flex-wrap: wrap; 
    justify-content: center; 
    gap: 5px;
  }

  .nav-links a {
    font-size: 16px; 
    padding: 6px 10px;
    white-space: nowrap; 
  }
}

nav {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  background-color: #222;
  padding: 10px;
  z-index: 1000;
  display: flex;
  justify-content: center;
  align-items: center;
  box-shadow: 0 0 20px #39ff14;
}

.nav-links {
  display: flex;
  gap: 5px;
}

.nav-links a {
  color: #39ff14;
  text-decoration: none;
  font-size: 18px;
  padding: 8px 12px;
  border: 2px solid #39ff14;
  border-radius: 5px;
  background: rgba(20, 20, 40, 0.8);
  box-shadow: 0 0 10px #39ff14 inset;
  transition: all 0.2s ease;
  font-family: 'Orbitron', Arial, sans-serif;
}

.nav-links a:hover {
  color: #0a0a1a;
  border-color: #fff;
  background-color: #39ff14;
  box-shadow: 0 0 20px #39ff14;
}

.game-container {
  text-align: center;
  margin-top: 60px;
}

.board {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  grid-template-rows: repeat(4, 1fr);
  gap: 10px;
  background-color: #bbada0;
  padding: 10px;
  border-radius: 10px;
  position: relative;
  width: 90vw; 
  max-width: 400px; 
  height: 90vw;
  max-height: 400px;
}

.cell {
  width: 100%;
  height: 100%;
  background-color: #ccc0b3;
  display: flex;
  justify-content: center;
  align-items: center;
  font-size: 2em;
  font-weight: bold;
  border-radius: 5px;
  transition: all 0.2s ease-in-out;
}
.cell[data-value="2"] { background-color: #eee4da; color: #776e65; }
.cell[data-value="4"] { background-color: #ede0c8; color: #776e65; }
.cell[data-value="8"] { background-color: #f2b179; color: #fff; }
.cell[data-value="16"] { background-color: #f59563; color: #fff; }
.cell[data-value="32"] { background-color: #f67c5f; color: #fff; }
.cell[data-value="64"] { background-color: #f65e3b; color: #fff; }
.cell[data-value="128"] { background-color: #edcf72; color: #fff; }
.cell[data-value="256"] { background-color: #edcc61; color: #fff; }
.cell[data-value="512"] { background-color: #edc850; color: #fff; }
.cell[data-value="1024"] { background-color: #edc53f; color: #fff; }
.cell[data-value="2048"] { background-color: #edc22e; color: #fff; }

.score {
  font-size: 1.5em;
  margin-top: 10px;
}

button {
  padding: 10px 20px;
  margin-top: 10px;
  font-size: 1.2em;
  cursor: pointer;
  border: none;
  background-color: #1DB954;
  color: white;
  border-radius: 5px;
  font-family: 'Orbitron', Arial, sans-serif;
  background-color: #222;
  color: #39ff14;
  border: 2px solid #39ff14;
  border-radius: 5px;
  box-shadow: 0 0 10px #39ff14 inset;
  transition: all 0.2s ease;
}

button:hover {
  background-color: #39ff14;
  color: #0a0a1a;
  border-color: #fff;
  box-shadow: 0 0 20px #39ff14;
}

.game-over {
  display: none;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-size: 2em;
  background: rgba(0, 0, 0, 0.7);
  color: white;
  padding: 20px;
  border-radius: 10px;
}
#controls {
  display: flex;
  flex-direction: column;
  align-items: center;
  margin-top: 10px;
}

#controls div {
  display: flex;
  gap: 10px;
}

button {
  font-size: 24px;
  padding: 10px;
  cursor: pointer;
}

@media (max-width: 600px) {
  .board {
    width: 90vw;
    height: 90vw;
    max-width: 350px;
    max-height: 350px;
  }

  .cell {
    font-size: 6vw; 
  }
}

@media (max-width: 400px) {
  .board {
    width: 95vw;
    height: 95vw;
    max-width: 320px;
    max-height: 320px;
  }

  .cell {
    font-size: 8vw;
  }
}

@media (max-width: 600px) {
  nav {
    flex-direction: column; 
    padding: 5px 0; 
  }

  .nav-links {
    flex-direction: column; 
    gap: 5px;
    width: 100%;
    align-items: center;
  }

  .nav-links a {
    font-size: 16px; 
    padding: 6px 10px; 
    width: 90%; 
    text-align: center; 
  }
}