body {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
}

h1 {
  background-color: cadetblue;
  width: 100%;
  color: white;
  text-align: center;
}

.grade-table,
tr,
td {
  border: 1px solid black;
  text-align: center;
  padding: 3px;
  margin-bottom: 10px;
}

.grade-table thead {
  background-color: cadetblue;
  color: white;
}

#score {
  border-radius: 7px;
  width: 200px;
}

#btn-cal {
  width: 100px;
  height: 30px;
  background-color: cadetblue;
  color: white;
  border: none;
  cursor: pointer;
  transition: all 0.3s ease-in;
}

#btn-cal:hover {
  border-radius: 15px;
}