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

body {
  background: linear-gradient(45deg, #8347a0, #d40866);
  background-size: 400% 400%;
  animation: GradientBackground 10s ease infinite;
}

@keyframes GradientBackground {
  0% {
    background-position: 0% 50%;
  }

  50% {
    background-position: 100% 50%;
  }

  100% {
    background-position: 0% 50%;
  }
}

body,
input,
button {
  font-family: "Open Sans", sans-serif;
}

input,
button {
  font-size: 16px;
}

.head_bar {
  padding: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
}

main {
  max-width: 800px;
  width: 80%;
  margin: 0 auto;
  padding: 16px;
}

.input_section {
  display: flex;
  flex-direction: column;
  padding: 16px;
  border: 4px solid #fff;
  border-radius: 10px;
}

.input_section > h3 {
  text-align: center;
  color: violet;
}

.input_section > form > button {
  display: block;
  width: 100%;
}

.input_section > form > button > span {
  font-weight: bold;
}

.input_section > form > .input > label {
  color: cornflowerblue;
  font-weight: bold;
  font-size: 40px;
}

.input_section > form > .input_inline {
  margin: 12px 0;
  display: flex;
  align-items: center;
}

.input_section > form > .input_inline > label {
  color: violet;
  font-weight: bold;
  margin-right: 10px;
}

.search_section {
  margin: 16px 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 16px;
  border: 4px solid #fff;
  border-radius: 10px;
}

.search_section > h3 {
  color: violet;
}

.search_section > form {
  padding: 16px;
  width: 100%;
  display: grid;
  grid-template-columns: auto 1fr 0.5fr;
  grid-gap: 10px;
}

.search_section > form > label {
  display: flex;
  align-items: center;
  color: violet;
  font-weight: bold;
}

.search_section > form > input {
  padding: 5px;
  border-radius: 5px;
}

.book_shelf {
  margin: 16px 0 0 0;
  border: 1px solid black;
  padding: 16px;
  border: 4px solid #fff;
  border-radius: 10px;
}

.book_shelf > h3 {
  color: violet;
}

.book_shelf > .book_list {
  padding: 16px;
}

.book_shelf > .book_list > .book_item {
  padding: 8px 16px 16px 16px;
  border: 1px solid black;
  border-radius: 5px;
  margin: 10px 0;
}

.book_shelf > .book_list > .book_item > h3,
p {
  margin: 8px 0;
}

.book_shelf > .book_list > .book_item > .action > button {
  border: 0;
  padding: 5px;
  margin: 0 5px 0 0;
  border-radius: 5px;
  cursor: pointer;
}

.book_shelf > .book_list > .book_item > .action > .green {
  background-color: darkgreen;
  color: white;
}

.book_shelf > .book_list > .book_item > .action > .red {
  background-color: darkred;
  color: white;
}

.card-title,
.card-text {
  text-transform: capitalize;
}