.learning-board{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px}.pdf-page{max-width:100%;height:auto;background:white}.reader-tools{display:flex;flex-wrap:wrap;gap:12px;align-items:center}.reader-tools input{max-width:100px}@media(max-width:900px){.learning-board{grid-template-columns:1fr}}