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

#grid-container {
  width: 400px;
  height: 400px;
  display: flex;
  flex-wrap: wrap;
  margin: 50px auto 20px;
  cursor: pointer;
}

/* 默认细胞 */
.cell {
  width: 20px;
  height: 20px;
  border: 1px solid black;
  border-radius: 3px;
}

/* 激活细胞 */
.alive {
  background-color: #5bbe5b;
  border-color: #0b6c0b;
}

/* 死亡细胞 */
.dead {
  background-color: white;
  border-color: #b1b1b1;
}

.actions {
  text-align: center;
}