.resources-hero {
    padding: 8rem 2.5rem 3rem;
    width: 100%;
    max-width: 100%;
    margin: 0 auto;
    text-align: center;
    box-sizing: border-box;
}

.back-link {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--primary);
    font-weight: 600;
    font-size: 0.95rem;
    margin-bottom: 1.5rem;
    transition: transform var(--transition-fast);
}

.back-link:hover {
    transform: translateX(-4px);
    color: var(--secondary);
}

.resources-hero h1 {
    font-size: 3rem;
    margin-bottom: 0.5rem;
    background: linear-gradient(135deg, var(--text-primary) 40%, #1e3a8a 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.chapter-ref {
    display: inline-block;
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--secondary);
    margin-bottom: 1rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.resources-hero p {
    font-size: 1.15rem;
    color: var(--text-secondary);
    max-width: 750px;
    margin: 0 auto 3rem;
}

.explorer-container {
    width: 100%;
    max-width: 100%;
    margin: 0 auto 6rem;
    padding: 0 2.5rem;
    display: grid;
    grid-template-columns: 0.6fr 1.4fr;
    gap: 2.5rem;
    align-items: start;
    box-sizing: border-box;
}

@media (max-width: 900px) {
    .explorer-container {
        grid-template-columns: 1fr;
    }
}

.sidebar-chapters {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 1.5rem;
    max-height: 80vh;
    overflow-y: auto;
    position: sticky;
    top: 7rem;
    min-width: 0;
}

.chapter-menu-item {
    display: block;
    width: 100%;
    text-align: left;
    padding: 0.75rem 1rem;
    border-radius: 8px;
    border: none;
    background: transparent;
    color: var(--text-secondary);
    font-size: 0.85rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
    margin-bottom: 0.25rem;
    line-height: 1.4;
}

.chapter-menu-item:hover {
    background: #f1f5f9;
    color: var(--text-primary);
}

.chapter-menu-item.active {
    background: var(--primary-glow);
    color: var(--primary);
}

/* Main Content area */
.content-panel {
    background: var(--bg-card);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 2.5rem;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.02);
    min-width: 0;
}

@media (max-width: 600px) {
    .explorer-container {
        padding: 0 1rem;
        gap: 1.25rem;
    }

    .sidebar-chapters,
    .content-panel {
        padding: 1.25rem;
    }

    .exercise-block {
        padding: 1.25rem;
    }
}

.chapter-header h2 {
    font-family: var(--font-heading);
    font-size: 1.75rem;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.chapter-desc {
    font-size: 0.95rem;
    color: var(--text-secondary);
    margin-bottom: 2rem;
    line-height: 1.6;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 1rem;
}

.exercise-block {
    margin-bottom: 2.5rem;
    background: white;
    border: 1px solid var(--border-color);
    border-radius: 14px;
    padding: 1.75rem;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.02);
}

.exercise-header-title h3 {
    font-family: var(--font-heading);
    font-size: 1.25rem;
    color: var(--text-primary);
    margin-bottom: 1.25rem;
    display: flex;
    align-items: center;
    gap: 0.6rem;
}

/* Enoncé box */
.exercise-enonce-box {
    background: #f8fafc;
    border: 1px solid #e2e8f0;
    border-left: 4px solid var(--primary);
    border-radius: 8px;
    padding: 1.25rem;
    margin-bottom: 1.5rem;
}

.enonce-label {
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--primary);
    display: flex;
    align-items: center;
    gap: 0.4rem;
    margin-bottom: 0.5rem;
    text-transform: uppercase;
    letter-spacing: 0.04em;
}

.exercise-enonce-box p {
    font-size: 0.95rem;
    color: #334155;
    line-height: 1.65;
}

/* Metadata Box */
.exercise-meta-box {
    background: #f0fdf4;
    border: 1px solid #bbf7d0;
    border-radius: 10px;
    padding: 1.25rem;
    margin-bottom: 1.5rem;
}

.meta-badges-row {
    display: flex;
    gap: 0.6rem;
    flex-wrap: wrap;
    margin-bottom: 1rem;
}

.meta-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    font-size: 0.8rem;
    font-weight: 600;
    padding: 0.3rem 0.75rem;
    border-radius: 50px;
}

.badge-modalite {
    background: #dbeafe;
    color: #1e40af;
}

.badge-duree {
    background: #fef3c7;
    color: #92400e;
}

.badge-ia {
    background: #e0e7ff;
    color: #3730a3;
}

.meta-details-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 0.75rem;
    margin-bottom: 1rem;
    font-size: 0.88rem;
}

@media (max-width: 768px) {
    .meta-details-grid {
        grid-template-columns: 1fr;
    }
}

.meta-detail-item {
    background: #ffffff;
    padding: 0.6rem 0.85rem;
    border-radius: 6px;
    border: 1px solid rgba(16, 185, 129, 0.2);
}

.meta-detail-item strong {
    display: block;
    font-size: 0.8rem;
    color: #065f46;
    margin-bottom: 0.2rem;
}

.meta-detail-item span {
    color: #1f2937;
}

.meta-criteria-section {
    background: #ffffff;
    padding: 0.85rem 1rem;
    border-radius: 6px;
    border: 1px solid rgba(16, 185, 129, 0.2);
    font-size: 0.88rem;
}

.meta-criteria-section strong {
    display: block;
    color: #065f46;
    margin-bottom: 0.5rem;
}

.meta-criteria-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.meta-criteria-list li {
    display: flex;
    align-items: center;
    color: #374151;
    margin-bottom: 0.35rem;
    line-height: 1.4;
}

.accordion-btn {
    width: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.85rem 1.25rem;
    border-radius: 8px;
    border: 1px solid var(--primary);
    background: white;
    color: var(--primary);
    font-weight: 700;
    font-size: 0.9rem;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.accordion-btn:hover {
    background: var(--primary-glow);
}

.accordion-content {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease-out;
    padding: 0 1.25rem;
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.6;
    background: #f8fafc;
    border-radius: 0 0 8px 8px;
}

.accordion-content.open {
    max-height: 1500px;
    padding: 1.25rem;
    border: 1px solid var(--border-color);
    border-top: none;
}

.guideline-section {
    margin-bottom: 1rem;
}

.guideline-section:last-child {
    margin-bottom: 0;
}

.guideline-section strong {
    color: var(--text-primary);
    display: block;
    margin-bottom: 0.35rem;
}

.exercise-response-list {
    margin: 0.5rem 0 0.75rem 1.25rem;
    padding-left: 0.5rem;
}

.exercise-response-list li {
    margin-bottom: 0.35rem;
    line-height: 1.55;
    color: var(--text-primary);
}

/* Bibliography block */
.bibliography-section {
    width: 100%;
    max-width: 100%;
    margin: 0 auto 6rem;
    padding: 2rem 2.5rem 0;
    border-top: 1px solid var(--border-color);
    box-sizing: border-box;
}

.bibliography-section h3 {
    font-family: var(--font-heading);
    font-size: 1.1rem;
    color: var(--text-primary);
    margin-bottom: 1rem;
}

.bibliography-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.bibliography-list li {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-bottom: 0.75rem;
    line-height: 1.5;
    text-indent: -1.5rem;
    padding-left: 1.5rem;
}