/* Learning Hub — browsable skill reference, no test, no sign-up */

.hub-hero {
    padding: var(--space-2xl) 0 var(--space-3xl);
}

.hub-section-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: var(--space-md);
    margin-top: var(--space-lg);
}

.hub-section-card {
    display: flex;
    flex-direction: column;
    gap: var(--space-xs);
    padding: var(--space-lg);
    background: var(--bg-card);
    border: 1px solid var(--border-subtle);
    border-left: 3px solid var(--brand-orange);
    border-radius: 16px;
    text-decoration: none;
    transition: all 0.3s ease;
}

.hub-section-card:hover {
    background: var(--bg-card-hover);
    border-color: var(--border-medium);
    transform: translateY(-4px);
}

.hub-section-title {
    font-size: var(--text-xl);
    font-weight: 700;
    color: var(--text-primary);
}

.hub-section-desc {
    color: var(--text-secondary);
    line-height: 1.5;
}

.hub-section-cta {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    font-size: var(--text-sm);
    font-weight: 600;
    color: var(--text-tertiary);
    margin-top: 0.3rem;
}

.hub-more-note {
    color: var(--text-tertiary);
    font-size: var(--text-sm);
    margin-top: var(--space-lg);
}

.hub-grid-label,
.hub-block-label {
    font-size: var(--text-xs);
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--text-tertiary);
    margin: var(--space-lg) 0 var(--space-sm);
}

.hub-skill-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
    gap: var(--space-sm);
    margin-bottom: var(--space-lg);
}

.hub-skill-card {
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
    text-align: left;
    padding: var(--space-md);
    background: var(--bg-card);
    border: 1px solid var(--border-subtle);
    border-radius: 14px;
    cursor: pointer;
    font-family: inherit;
    transition: all 0.2s ease;
}

.hub-skill-card:hover {
    background: var(--bg-card-hover);
    border-color: var(--border-medium);
}

.hub-skill-card.is-active {
    border-color: var(--brand-orange);
    background: rgba(244, 123, 32, 0.08);
}

.hub-skill-title {
    font-size: var(--text-sm);
    font-weight: 700;
    color: var(--text-primary);
}

.hub-skill-blurb {
    font-size: var(--text-xs);
    color: var(--text-tertiary);
    line-height: 1.5;
}

.hub-detail {
    background: var(--bg-card);
    border: 1px solid var(--border-subtle);
    border-radius: 20px;
    padding: var(--space-lg);
}

.hub-detail-kicker-row {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 0.6rem;
    margin-bottom: var(--space-sm);
}

.hub-detail-kicker {
    display: inline-block;
    font-size: var(--text-sm);
    font-weight: 700;
    color: var(--brand-orange);
}

.hub-bank-tag {
    font-size: var(--text-xs);
    font-family: 'Courier New', monospace;
    color: var(--text-tertiary);
    background: rgba(255, 255, 255, 0.04);
    border: 1px solid var(--border-subtle);
    border-radius: 6px;
    padding: 0.15rem 0.5rem;
}

.hub-detail-explainer {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: var(--space-sm);
}

.hub-detail-trap {
    color: var(--text-secondary);
    line-height: 1.6;
    padding: 0.75rem 1rem;
    background: rgba(244, 123, 32, 0.06);
    border-left: 3px solid var(--brand-orange);
    border-radius: 8px;
}

.hub-detail-trap strong {
    color: var(--text-primary);
}

.hub-worked {
    margin-top: var(--space-lg);
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
}

.hub-passage,
.hub-question,
.hub-steps {
    padding: var(--space-md);
    background: rgba(255, 255, 255, 0.02);
    border: 1px solid var(--border-subtle);
    border-radius: 14px;
}

.hub-passage-title {
    font-size: var(--text-lg);
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--space-sm);
}

.hub-passage-body p {
    color: var(--text-secondary);
    line-height: 1.75;
    margin-bottom: 0.9rem;
}

.hub-passage-body p:last-child {
    margin-bottom: 0;
}

.hub-question-stem {
    color: var(--text-primary);
    font-weight: 600;
    line-height: 1.6;
    margin-bottom: var(--space-sm);
}

.hub-options {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.hub-option {
    display: flex;
    align-items: flex-start;
    gap: 0.7rem;
    padding: 0.65rem 0.85rem;
    border-radius: 10px;
    border: 1px solid var(--border-subtle);
    color: var(--text-secondary);
    line-height: 1.55;
}

.hub-option.is-correct {
    border-color: var(--biology-primary);
    background: rgba(16, 185, 129, 0.08);
}

.hub-option-id {
    flex-shrink: 0;
    font-weight: 700;
    color: var(--text-tertiary);
}

.hub-option.is-correct .hub-option-id {
    color: var(--biology-primary);
}

.hub-option-text {
    flex: 1;
}

.hub-option-flag {
    flex-shrink: 0;
    font-size: var(--text-xs);
    font-weight: 700;
    color: var(--biology-primary);
    white-space: nowrap;
}

.hub-steps ol {
    color: var(--text-secondary);
    line-height: 1.7;
    padding-left: 1.3rem;
    display: flex;
    flex-direction: column;
    gap: 0.6rem;
}

.hub-hint {
    color: var(--text-tertiary);
    font-size: var(--text-sm);
    margin-top: var(--space-md);
}

.hub-hint i {
    margin-right: 0.4rem;
}

.hub-back-link {
    margin-top: var(--space-sm);
}

.hub-back-link a {
    color: var(--text-tertiary);
    text-decoration: none;
    font-size: var(--text-sm);
}

.hub-back-link a:hover {
    color: var(--text-secondary);
}