/* Center the main container */
.books-container {
    max-width: 1000px; /* Limits width to keep it centered */
    margin: 40px auto 80px;
    padding: 0 20px;
}

.filter-box {
    background: var(--card-bg);
    padding: 25px;
    border-radius: 15px;
    margin-bottom: 40px;
    border: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: center; /* Center the filter content */
    gap: 15px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.05);
}

.filter-box label { font-weight: 800; color: var(--primary-color); }

.filter-box select {
    padding: 12px 25px;
    border-radius: 10px;
    border: 1px solid var(--border-color);
    font-family: 'Cairo';
    font-weight: 700;
    background: var(--bg-color);
    color: var(--text-color);
    outline: none;
    cursor: pointer;
}

.books-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 30px;
    justify-items: center; /* Centers cards inside the grid */
}

.book-card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    padding: 30px;
    text-align: center;
    transition: all 0.3s ease;
    display: flex;
    flex-direction: column;
    width: 100%;
    max-width: 320px;
    box-shadow: 0 4px 10px rgba(0,0,0,0.03);
}

.book-card:hover {
    transform: translateY(-10px);
    border-color: #2980b9;
    box-shadow: 0 15px 35px rgba(41, 128, 185, 0.2);
}

.book-icon { font-size: 3.5rem; margin-bottom: 20px; display: block; }
.book-title { font-weight: 800; font-size: 1.2rem; margin-bottom: 12px; line-height: 1.5; color: var(--text-color); min-height: 3.6rem; }
.book-grade { font-size: 0.85rem; color: #2980b9; font-weight: 800; background: rgba(41, 128, 185, 0.1); padding: 5px 15px; border-radius: 30px; display: inline-block; margin-bottom: 25px; }

.book-actions { display: flex; gap: 12px; }

.book-btn {
    flex: 1;
    padding: 12px;
    border-radius: 10px;
    text-decoration: none !important;
    font-weight: 800;
    font-size: 0.95rem;
    transition: 0.2s;
    border: none;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

.btn-open-book { background: #2980b9; color: white !important; }
.btn-save-book { background: #27ae60; color: white !important; }