style.css

* {
  box-sizing: border-box;
}

.btn {
  background-color: aqua;
  border: 1px solid black;
  border-radius: 5px;
  padding: 0.6rem 2rem;
  text-decoration: none;
  font-weight: bold;
}

main {
  display: flex;
  text-align: center;
  align-items: center;
  justify-content: center;
}

.intro {
  align-self: center;
  justify-self: center;
  display: block;
  width: 40%;
}

.intro input {
  margin-bottom: 1rem;
}

.container {
  display: inline-block;
  margin: 20px auto;
  align-items: center;
  justify-content: center;
}

.row {
  display: flex;
  height: 40px;
}

.cell {
  background: white;
  width: 40px;
  border: 2px solid black;
  text-align: center;
  vertical-align: center;
}

#container-ships {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

.ships {
  display: flex;
  align-items: center;
  justify-content: center;
}

#ships-vertical {
  display: flex;
  /* align-items: center; */
  justify-content: center;
  flex-direction: row;
}

.ship {
  background-color: orange;
  margin: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 2px solid black;
}

.finish {
  display: flex;
  width: 100%;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}