* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  background: linear-gradient(135deg, #1e293b, #0f172a);
  color: #f1f5f9;
  min-height: 100vh;
}

.container {
  width: 100%;
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 20px;
}

.library-app {
  width: 100%;
  max-width: 800px;
  background: #020617;
  border-radius: 16px;
  padding: 30px;
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.6);
}

h1 {
  margin: 0;
  text-align: center;
  font-size: 28px;
}

.subtitle {
  text-align: center;
  color: #94a3b8;
  margin-bottom: 25px;
}

.form-section {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-bottom: 25px;
}

.form-section input {
  padding: 10px;
  border-radius: 6px;
  border: 1px solid #334155;
  background: #020617;
  color: white;
}

.form-section input:focus {
  outline: 1px solid #38bdf8;
}

.checkbox-row {
  grid-column: span 2;
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
}

#addBookBtn {
  grid-column: span 2;
  padding: 12px;
  border: none;
  background: #22c55e;
  color: black;
  border-radius: 8px;
  cursor: pointer;
  font-weight: bold;
}

#addBookBtn:hover {
  background: #16a34a;
}

.top-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 20px;
  gap: 10px;
}

#searchInput {
  flex: 1;
  padding: 10px;
  border-radius: 6px;
  border: 1px solid #334155;
  background: #020617;
  color: white;
}

#bookCount {
  font-size: 14px;
  color: #94a3b8;
}

.book-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.book-card {
  background: #020617;
  border: 1px solid #334155;
  border-radius: 10px;
  padding: 15px;
  display: flex;
  flex-direction: column;
}

.book-card h3 {
  margin: 0 0 6px 0;
}

.book-card p {
  margin: 2px 0;
  font-size: 14px;
  color: #cbd5f5;
}

.status {
  margin-top: 8px;
  font-size: 13px;
}

.status.read {
  color: #22c55e;
}

.status.unread {
  color: #f87171;
}

.card-buttons {
  margin-top: 12px;
  display: flex;
  gap: 8px;
}

.toggle-btn {
  flex: 1;
  background: #38bdf8;
  border: none;
  padding: 8px;
  border-radius: 6px;
  cursor: pointer;
}

.toggle-btn:hover {
  background: #0ea5e9;
}

.delete-btn {
  flex: 1;
  background: #ef4444;
  border: none;
  padding: 8px;
  border-radius: 6px;
  cursor: pointer;
  color: white;
}

.delete-btn:hover {
  background: #dc2626;
}

.empty-message {
  text-align: center;
  padding: 20px;
  color: #94a3b8;
}

@media (max-width: 600px) {
  .form-section {
    grid-template-columns: 1fr;
  }

  .checkbox-row,
  #addBookBtn {
    grid-column: span 1;
  }

  .top-bar {
    flex-direction: column;
    align-items: stretch;
  }
}