:root {
    --bg-main: #0d1117;
    --bg-card: #161b22;
    --bg-elevated: #1f2630;
    --border: #30363d;
    --text: #e6edf3;
    --muted: #8b949e;
    --accent-x: #d29922;
    --accent-llg: #58a6ff;
    --accent-didaktika: #3fb950;
    --danger: #f85149;
    --purple: #bc8cff;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    container-type: scroll-state;
}

body {
    background: var(--bg-main);
    color: var(--text);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    line-height: 1.6;
}

/* Barre supérieure */
.topbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.8rem 1.5rem;
    background: var(--bg-card);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 40;
    gap: 1rem;
    flex-wrap: wrap;
}

.brand {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.badge-x {
    background: var(--accent-x);
    color: #000;
    font-weight: 900;
    padding: 0.2rem 0.6rem;
    border-radius: 4px;
    font-family: Georgia, serif;
    letter-spacing: 0.5px;
}

.brand h1 {
    font-size: 1.15rem;
    letter-spacing: 0.5px;
}

.brand small {
    color: var(--muted);
    font-weight: 400;
    font-size: 0.85rem;
    margin-left: 0.35rem;
}

.level-tabs {
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem;
}

.level-tabs button {
    background: transparent;
    color: var(--muted);
    border: 1px solid var(--border);
    padding: 0.4rem 0.9rem;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.88rem;
    transition: all 0.15s ease;
}

.level-tabs button:hover {
    color: var(--text);
    border-color: var(--accent-llg);
}

.level-tabs button.active {
    background: var(--accent-llg);
    color: #000;
    font-weight: 600;
    border-color: var(--accent-llg);
}

.btn-didaktika {
    color: var(--accent-didaktika);
    text-decoration: none;
    border: 1px solid var(--accent-didaktika);
    padding: 0.4rem 0.85rem;
    border-radius: 6px;
    font-size: 0.85rem;
    font-weight: 600;
    transition: background 0.15s ease;
}

.btn-didaktika:hover {
    background: rgba(63, 185, 80, 0.15);
}

/* Espace de travail principal */
.workspace {
    display: grid;
    grid-template-columns: 310px 1fr;
    min-height: calc(100vh - 60px);
}

@media (max-width: 920px) {
    .workspace {
        grid-template-columns: 1fr;
    }
}

/* Barre latérale Piliers */
.sidebar {
    border-right: 1px solid var(--border);
    padding: 1.2rem 1rem;
    background: #090d13;
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.sidebar-section-title {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--muted);
    font-weight: 700;
    margin-bottom: 0.25rem;
}

.pilier-btn {
    width: 100%;
    text-align: left;
    background: var(--bg-card);
    color: var(--text);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 0.75rem 0.9rem;
    cursor: pointer;
    transition: all 0.15s ease;
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.pilier-btn:hover {
    border-color: var(--accent-llg);
    background: var(--bg-elevated);
}

.pilier-btn.active {
    border-color: var(--accent-llg);
    background: rgba(88, 166, 255, 0.12);
    box-shadow: inset 3px 0 0 var(--accent-llg);
}

.pilier-btn-top {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-weight: 600;
    font-size: 0.9rem;
}

.pilier-code-badge {
    font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
    font-size: 0.72rem;
    color: var(--accent-llg);
    background: rgba(88, 166, 255, 0.14);
    padding: 0.1rem 0.45rem;
    border-radius: 4px;
}

.pilier-count {
    font-size: 0.75rem;
    color: var(--muted);
    background: var(--bg-main);
    padding: 0.1rem 0.5rem;
    border-radius: 999px;
    border: 1px solid var(--border);
}

.pilier-btn-sub {
    font-size: 0.78rem;
    color: var(--muted);
    line-height: 1.35;
}

.stats-box {
    margin-top: auto;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 0.85rem;
    font-size: 0.82rem;
}

.stats-box h4 {
    font-size: 0.76rem;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--muted);
    margin-bottom: 0.5rem;
}

.stats-row {
    display: flex;
    justify-content: space-between;
    padding: 0.2rem 0;
    border-bottom: 1px dashed rgba(48, 54, 61, 0.6);
}

.stats-row:last-child {
    border-bottom: none;
}

/* Zone de contenu */
.content-area {
    padding: 1.5rem 2rem 5rem;
    max-width: 1160px;
}

.filters-bar {
    display: flex;
    gap: 0.75rem;
    margin-bottom: 1rem;
    flex-wrap: wrap;
}

.filters-bar input,
.filters-bar select {
    background: var(--bg-card);
    color: var(--text);
    border: 1px solid var(--border);
    padding: 0.6rem 0.9rem;
    border-radius: 6px;
    font-size: 0.9rem;
}

.filters-bar input {
    flex: 2;
    min-width: 240px;
}

.filters-bar select {
    flex: 1;
    min-width: 170px;
}

.filters-bar input:focus,
.filters-bar select:focus {
    outline: none;
    border-color: var(--accent-llg);
}

.btn-secondary {
    background: var(--bg-card);
    color: var(--text);
    border: 1px solid var(--border);
    padding: 0.6rem 0.95rem;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.85rem;
    font-weight: 500;
    white-space: nowrap;
}

.btn-secondary:hover {
    border-color: var(--accent-llg);
    color: var(--accent-llg);
}

.status-banner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.55rem 0.9rem;
    margin-bottom: 1.25rem;
    background: rgba(88, 166, 255, 0.07);
    border: 1px solid rgba(88, 166, 255, 0.25);
    border-radius: 6px;
    font-size: 0.85rem;
    color: var(--muted);
}

.status-banner strong {
    color: var(--text);
}

.section-divider {
    margin: 1.6rem 0 0.9rem;
    padding-bottom: 0.4rem;
    border-bottom: 1px solid var(--border);
    color: var(--accent-llg);
    font-size: 0.95rem;
    font-weight: 700;
    letter-spacing: 0.02em;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

/* Cartes mathématiques */
.math-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 1.25rem 1.4rem;
    margin-bottom: 1.2rem;
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.math-card.highlight-target {
    border-color: var(--accent-x);
    box-shadow: 0 0 0 2px rgba(210, 153, 34, 0.35);
}

.math-card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.75rem;
    border-bottom: 1px solid var(--border);
    padding-bottom: 0.6rem;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.math-card-meta {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.code-ref {
    font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
    font-size: 0.8rem;
    font-weight: 700;
    color: var(--text);
    background: #0d1117;
    border: 1px solid var(--border);
    padding: 0.15rem 0.5rem;
    border-radius: 4px;
}

.tag {
    font-size: 0.72rem;
    padding: 0.15rem 0.55rem;
    border-radius: 4px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.03em;
}

.tag-LLG_PONT {
    background: rgba(88, 166, 255, 0.18);
    color: var(--accent-llg);
    border: 1px solid rgba(88, 166, 255, 0.35);
}

.tag-EXPERTES {
    background: rgba(210, 153, 34, 0.18);
    color: var(--accent-x);
    border: 1px solid rgba(210, 153, 34, 0.35);
}

.tag-SPE {
    background: rgba(63, 185, 80, 0.18);
    color: var(--accent-didaktika);
    border: 1px solid rgba(63, 185, 80, 0.35);
}

.tag-nature {
    background: rgba(188, 140, 255, 0.14);
    color: var(--purple);
    border: 1px solid rgba(188, 140, 255, 0.3);
}

.priority-stars {
    font-size: 0.78rem;
    color: var(--accent-x);
    font-weight: 700;
    letter-spacing: 1px;
}

.math-card-title {
    font-size: 1.08rem;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 0.65rem;
}

.hypotheses-line {
    font-size: 0.9rem;
    color: var(--muted);
    margin-bottom: 0.65rem;
    font-style: italic;
}

.enonce-box {
    background: rgba(13, 17, 23, 0.65);
    border: 1px solid rgba(48, 54, 61, 0.8);
    border-radius: 6px;
    padding: 0.9rem 1.1rem;
    font-size: 0.96rem;
    overflow-x: auto;
}

.enonce-box p + p,
.enonce-box ul {
    margin-top: 0.45rem;
}

.enonce-box ul {
    padding-left: 1.25rem;
}

/* Graphe de dépendances DAG */
.dag-bar {
    display: flex;
    flex-wrap: wrap;
    gap: 0.8rem;
    align-items: center;
    margin-top: 0.75rem;
    font-size: 0.8rem;
    color: var(--muted);
}

.dag-group {
    display: flex;
    align-items: center;
    gap: 0.35rem;
    flex-wrap: wrap;
}

.dag-pill {
    background: #0d1117;
    color: var(--accent-llg);
    border: 1px solid rgba(88, 166, 255, 0.35);
    border-radius: 4px;
    padding: 0.1rem 0.45rem;
    font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
    font-size: 0.74rem;
    cursor: pointer;
    transition: all 0.15s ease;
}

.dag-pill:hover {
    background: var(--accent-llg);
    color: #000;
}

.dag-pill.dag-downstream {
    color: var(--accent-didaktika);
    border-color: rgba(63, 185, 80, 0.35);
}

.dag-pill.dag-downstream:hover {
    background: var(--accent-didaktika);
    color: #000;
}

/* Barre d'actions de la carte */
.card-actions {
    display: flex;
    gap: 0.65rem;
    margin-top: 0.95rem;
    flex-wrap: wrap;
}

.btn-action {
    background: #0d1117;
    color: var(--text);
    border: 1px solid var(--border);
    padding: 0.45rem 0.85rem;
    border-radius: 6px;
    font-size: 0.83rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.15s ease;
}

.btn-action-demo {
    border-color: rgba(88, 166, 255, 0.45);
    color: var(--accent-llg);
}

.btn-action-demo:hover,
.btn-action-demo[aria-expanded="true"] {
    background: rgba(88, 166, 255, 0.15);
    border-color: var(--accent-llg);
}

.btn-action-didaktika {
    border-color: rgba(63, 185, 80, 0.45);
    color: var(--accent-didaktika);
}

.btn-action-didaktika:hover {
    background: rgba(63, 185, 80, 0.15);
    border-color: var(--accent-didaktika);
}

/* Boîtes Démonstration & Crash-Test */
.drawer-panel {
    margin-top: 0.85rem;
}

.drawer-panel.hidden {
    display: none;
}

.idee-cle-box {
    padding: 0.6rem 0.85rem;
    background: rgba(210, 153, 34, 0.08);
    border-left: 3px solid var(--accent-x);
    font-size: 0.88rem;
    margin-bottom: 0.55rem;
    border-radius: 0 4px 4px 0;
}

.demo-box {
    padding: 0.85rem 1rem;
    background: #0d1117;
    border-left: 3px solid var(--accent-llg);
    font-size: 0.92rem;
    border-radius: 0 4px 4px 0;
    overflow-x: auto;
}

.crash-box {
    margin-top: 0.6rem;
    padding: 0.65rem 0.9rem;
    background: rgba(248, 81, 73, 0.08);
    border-left: 3px solid var(--danger);
    font-size: 0.88rem;
    border-radius: 0 4px 4px 0;
}

/* État vide / Niveaux à venir */
.empty-state {
    background: var(--bg-card);
    border: 1px dashed var(--border);
    border-radius: 8px;
    padding: 2.5rem 1.5rem;
    text-align: center;
    color: var(--muted);
}

.empty-state h3 {
    color: var(--text);
    margin-bottom: 0.5rem;
}

/* Modale native <dialog> Didaktika */
dialog.modal {
    margin: auto;
    width: 92vw;
    height: 86vh;
    max-width: 1400px;
    max-height: 920px;
    background: var(--bg-card);
    color: var(--text);
    border: 1px solid var(--border);
    border-radius: 10px;
    padding: 0;
    overflow: hidden;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.75);
}

dialog.modal[open] {
    display: flex;
    flex-direction: column;
}

dialog.modal::backdrop {
    background-color: rgba(0, 0, 0, 0.75);
    backdrop-filter: blur(3px);
}

.modal-content {
    width: 100%;
    height: 100%;
    display: flex;
    flex-direction: column;
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.8rem 1.2rem;
    border-bottom: 1px solid var(--border);
    background: #090d13;
}

.modal-title-group {
    display: flex;
    align-items: center;
    gap: 1rem;
    flex-wrap: wrap;
}

.modal-ext-link {
    font-size: 0.8rem;
    color: var(--accent-didaktika);
    text-decoration: none;
}

.modal-ext-link:hover {
    text-decoration: underline;
}

#close-modal {
    background: transparent;
    color: var(--muted);
    border: 1px solid var(--border);
    border-radius: 6px;
    width: 32px;
    height: 32px;
    cursor: pointer;
    font-size: 1rem;
}

#close-modal:hover {
    color: var(--text);
    border-color: var(--danger);
}

#didaktika-frame {
    flex: 1;
    border: none;
    width: 100%;
    background: #0d1117;
}

/* Signature & Pied de page */
.app-footer {
    margin-top: 2.5rem;
    padding-top: 1.2rem;
    border-top: 1px solid var(--border);
    text-align: center;
    font-size: 0.85rem;
    color: var(--muted);
}

.app-footer a,
.sidebar-credit a {
    color: var(--accent-llg);
    text-decoration: none;
}

.app-footer a:hover,
.sidebar-credit a:hover {
    text-decoration: underline;
}

.sidebar-credit {
    margin-top: 0.65rem;
    padding-top: 0.55rem;
    border-top: 1px solid var(--border);
    font-size: 0.78rem;
    color: var(--muted);
    text-align: center;
}

/* Sentinelle et bouton flottant Retour en haut */
.scroll-sentinel {
    height: 0;
    width: 0;
    visibility: hidden;
}

.back-to-top {
    position: fixed;
    right: 1.75rem;
    bottom: 1.75rem;
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background: var(--accent-llg);
    color: #000;
    border: 1px solid rgba(255, 255, 255, 0.25);
    font-size: 1.25rem;
    font-weight: 800;
    cursor: pointer;
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.55);
    z-index: 50;
    display: flex;
    align-items: center;
    justify-content: center;
    visibility: hidden;
    opacity: 0;
    translate: 0 20px;
    transition:
        visibility 0.25s,
        opacity 0.25s ease,
        translate 0.25s ease,
        background-color 0.15s ease;
}

.back-to-top:hover {
    background: var(--accent-x);
}

.scrolled .back-to-top {
    visibility: visible;
    opacity: 1;
    translate: 0 0;
}

@supports (container-type: scroll-state) {
    @container scroll-state(scrollable: top) {
        .back-to-top {
            visibility: visible;
            opacity: 1;
            translate: 0 0;
        }
    }
}