.os-main-heading { font-size: 1.6rem !important; padding-bottom: 0.6rem; border-bottom: 3px solid var(--color-primary); margin-top: 3rem !important; margin-bottom: 2rem !important; }
.subject-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; margin-bottom: var(--spacing-md); }
.subject-card { display: flex; flex-direction: column; gap: 6px; padding: 18px; background: var(--color-surface); border: 1px solid var(--color-border); border-radius: var(--radius); text-decoration: none; color: var(--color-text); transition: border-color 0.15s, transform 0.15s; }
.subject-card:hover { border-color: var(--color-primary); transform: translateY(-2px); }
.subject-card-icon { font-size: 1.7rem; }
.subject-card-title { font-weight: 800; font-size: 1.02rem; color: var(--color-text); }
.subject-card-desc { color: var(--color-text-muted); font-size: 0.85rem; }
@media (max-width: 900px) { .subject-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 480px) { .subject-grid { grid-template-columns: 1fr; } }