header {
  text-align: center;
  font-weight: bold;
  font-size: 20px;
  display: flex;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  justify-content: center;
}
.btn {
  display: block;
  width: 20px;
  text-align: center;
  height: 15px;
  margin-bottom: 5px;
  text-decoration: none;
  color: white;
  background: red;
}
.alert {
  background: red;
  color: white;
}
#submit {
  background: rgb(116, 71, 116);
  border: 1px solid darkred;
  padding: 5px 50px;
  border-radius: 5%;
}
span {
  color: rgb(58, 93, 145);
}
#book-img {
  margin-right: 5px;
  width: 25px;
}
#book-list {
  border: none;
}
#book-table {
  width: 100%;
  overflow-x: auto;
  margin: auto;
  border: none;
  margin-top: 50px;
  text-align: center;
  border-collapse: collapse;
  box-shadow: 0em 0em 0em 0.1em rgb(32, 9, 160);
}
#book-table th {
  color: darkcyan;
  padding: 0px 2em 0px 2em;
  border: none;
}
#books-form {
  font-size: 15px;
  text-align: center;
  font-family: 'Lucida Sans', 'Lucida Sans Regular', 'Lucida Grande',
    'Lucida Sans Unicode', Geneva, Verdana, sans-serif;
}
.form-group {
  margin: 15px;
  list-style: none;
}