style.css

#container {
  width: 60%;
  margin-left: auto;
  margin-right: auto;
}

#container h1 {
  font-family: 'Roboto Mono', monospace;
}

#book-form label {
  font-family: 'Roboto Mono', monospace;
  font-weight: 700;
  display: block;
  margin-bottom: 2px;
}

#book-form>div {
  margin-bottom: 20px;
}

#book-form div>input {
  font-weight: 700;
  border: 1px solid gray;
  border-radius: 5px;
  width: 100%;
  padding: 7px 0;
}

#book-form div>input:focus {
  outline: none;
}

#submit {
  padding: 6px 29px;
  border: 1px solid gray;
  border-radius: 3px;
  background-color: #fff;
  transition: background-color 100ms ease-in-out;
  margin-bottom: 30px;
}

#submit:hover {
  cursor: pointer;
  background-color: rgb(238, 235, 235);
}

#submit:active {
  background-color: #fff;
}

#data-book td {
  padding-bottom: 10px;
}

thead th {
  font-size: 18px;
  text-align: left;
  padding-bottom: 10px;
}

.error {
  background-color: red;
  color: white;
  padding: 10px;
  margin-bottom: 23px;
}

.success {
  background-color: green;
  color: white;
  padding: 10px;
  margin-bottom: 23px;
}

.delete {
  text-decoration: none;
  color: red;
}