style.css

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

h2,
p {
  color: lightgray;
}

button {
  padding: 15px;
  margin: 10px;
  border: 1px solid black;
  font-size: 1.1em;
  background-color: #76746a;
  cursor: pointer;
}
button:hover {
  transform: scale(1.1);
  box-shadow: 3px 3px 5px black;
}

input {
  background-color: #31312e;
  color: lightgray;
  border: 1px solid black;
}

footer {
  position: absolute;
  bottom: 0.5vh;
  left: 0.5vw;
}

#add-book {
  margin: 1em;
}

#modal {
  display: none;
  position: fixed;
  z-index: 1;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  overflow: auto;
}

#modal-content {
  background-color: #31312e;
  color: lightgray;
  margin: auto;
  padding: 20px;
  border: 1px solid black;
  width: 80%;
}

#close {
  color: #76746a;
  float: right;
  font-size: 28px;
  font-weight: bold;
}

#close:hover {
  color: #000;
  text-decoration: none;
  cursor: pointer;
}

#container {
  display: flex;
  flex-direction: row;
  flex-wrap: wrap;
}

.book-container {
  border: 2px solid black;
  border-radius: 5px;
  margin: 2vh;
  padding: 20px;
  width: 200px;
  height: 450px;
  background-color: #31312e;
  display: flex;
  flex-direction: column;
  justify-content: end;
}
.book-container:hover {
  transform: scale(1.1);
  box-shadow: 3px 3px 5px black;
}

.book-title,
.book-read {
  margin-bottom: 2em;
}

.toggle-read-btn {
  background-color: #76746a;
}

.delete-item-btn {
  background-color: #d72c2c;
  font-size: 1.5em;
}