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

body {
  font-family: Arial, sans-serif;
  background-color: #f4f4f4;
  padding: 40px;
}

.container {
  max-width: 1000px;
  margin: auto;
}

h1 {
  margin-bottom: 20px;
}

#new-book-btn {
  padding: 10px 20px;
  border: none;
  background: black;
  color: white;
  cursor: pointer;
  margin-bottom: 20px;
}

form {
  background: white;
  padding: 20px;
  border-radius: 10px;
  margin-bottom: 30px;

  display: flex;
  flex-direction: column;
  gap: 10px;
}

.hidden {
  display: none;
}

input {
  padding: 10px;
}

#books-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 20px;
}

.book-card {
  background: white;
  padding: 20px;
  border-radius: 10px;

  display: flex;
  flex-direction: column;
  gap: 10px;
}

.book-card button {
  padding: 10px;
  border: none;
  cursor: pointer;
}

.remove-btn {
  background: crimson;
  color: white;
}

.toggle-btn {
  background: steelblue;
  color: white;
}