.navigation-buttons {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 1rem;
    padding: 1rem;
    background: var(--color-card-bg);
    border-radius: 8px;
    margin-bottom: 2rem;
}

.nav-button {
    padding: 1rem;
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: 4px;
    color: var(--color-primary-text);
    text-decoration: none;
    text-align: center;
    transition: all 0.3s ease;
}

.nav-button:hover {
    background: var(--color-border);
    transform: translateY(-2px);
}

.exercise-content {
    display: none;
    margin-top: 2rem;
}

.exercise-content:target {
    display: block;
}

.back-to-top {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    padding: 1rem;
    background: var(--color-card-bg);
    border: 1px solid var(--color-border);
    border-radius: 4px;
    text-decoration: none;
    color: var(--color-primary-text);
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}