/* ==========================================
               DESIGN TOKENS
               ========================================== */
            :root {
                --os-bg-1: #0b1220;
                --os-bg-2: #141b2e;
                --os-bg-3: #1f2a44;

                --os-accent: #ff8a4c;
                --os-accent-soft: rgba(255, 138, 76, 0.18);
                --os-accent-strong: #ffa869;

                --os-glass: rgba(255, 255, 255, 0.07);
                --os-glass-strong: rgba(15, 19, 32, 0.78);
                --os-border: rgba(255, 255, 255, 0.14);
                --os-border-soft: rgba(255, 255, 255, 0.08);

                --os-text: #f4f6fb;
                --os-text-dim: rgba(244, 246, 251, 0.64);

                --os-content-bg: #f7f8fb;

                --os-close: #ff6b6b;
                --os-min: #ffd166;
                --os-max: #06d6a0;

                --os-shadow-window: 0 20px 45px -15px rgba(3, 6, 15, 0.65), 0 2px 8px rgba(3, 6, 15, 0.35);
                --os-shadow-dock: 0 14px 34px -12px rgba(3, 6, 15, 0.6);
                --os-shadow-menu: 0 18px 40px -14px rgba(3, 6, 15, 0.6);

                --os-radius-lg: 16px;
                --os-radius-md: 12px;
                --os-radius-sm: 8px;

                --os-blur: 22px;
                --os-fast: 140ms cubic-bezier(0.4, 0, 0.2, 1);
                --os-normal: 200ms cubic-bezier(0.4, 0, 0.2, 1);

                /* Personnalisable via config.SetFontFamily() */
                --os-font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
            }

            /* ==========================================
               RESET
               ========================================== */
            * {
                margin: 0;
                padding: 0;
                box-sizing: border-box;

                user-select: none;

                font-family: var(--os-font-family);
            }

            html, body {
                height: 100%;
                overflow: hidden;
            }

            :focus-visible {
                outline: 2px solid var(--os-accent);
                outline-offset: 2px;
                border-radius: 6px;
            }

            /* ==========================================
               BUREAU / FOND D'ÉCRAN
               ========================================== */
            #root {
                display: flex;
                flex-direction: column;

                width: 100vw;
                height: 100vh;
                overflow: hidden;

                position: relative;
                color: var(--os-text);

                background:
                    radial-gradient(circle at 15% 15%, rgba(255, 138, 76, 0.14), transparent 45%),
                    radial-gradient(circle at 85% 85%, rgba(6, 214, 160, 0.10), transparent 42%),
                    linear-gradient(160deg, var(--os-bg-1), var(--os-bg-2) 55%, var(--os-bg-3));
            }

            #root > header {
                flex: 0 0 auto;
                height: 40px;

                display: flex;
                align-items: center;
                padding: 0 16px;

                background: var(--os-glass);
                border-bottom: 1px solid var(--os-border-soft);
                backdrop-filter: blur(var(--os-blur));
                -webkit-backdrop-filter: blur(var(--os-blur));
            }

            #root > header::before {
                content: "🦊 Goupil";
                font-size: 13px;
                font-weight: 600;
                letter-spacing: 0.2px;
                color: var(--os-text-dim);
            }

            #root > main {
                flex: 1 1 auto;
                position: relative;
                overflow: hidden;
            }

            #root > footer {
                flex: 0 0 auto;
                align-self: stretch;

                width: 100%;
                height: 56px;

                display: flex;
                align-items: center;
                gap: 10px;

                padding: 0 10px;

                background: var(--os-glass-strong);
                border-top: 1px solid var(--os-border);
                box-shadow: 0 -10px 26px -14px rgba(3, 6, 15, 0.55);
                backdrop-filter: blur(var(--os-blur)) saturate(160%);
                -webkit-backdrop-filter: blur(var(--os-blur)) saturate(160%);
            }

            #footer-apps {
                flex: 1 1 auto;

                display: flex;
                align-items: center;
                gap: 10px;
                height: 100%;

                overflow-x: auto;
                overflow-y: hidden;
                scrollbar-width: none;
            }

            #footer-apps::-webkit-scrollbar {
                display: none;
            }

            /* ==========================================
               FENÊTRES D'APPLICATION
               ========================================== */
            main > section.app {
                position: absolute;

                min-width: 250px;
                width: 250px;

                min-height: 100px;
                height: 100px;

                background: var(--os-glass-strong);
                border: 1px solid var(--os-border);
                border-radius: var(--os-radius-lg);
                box-shadow: var(--os-shadow-window);
                backdrop-filter: blur(var(--os-blur)) saturate(160%);
                -webkit-backdrop-filter: blur(var(--os-blur)) saturate(160%);

                overflow: hidden;
                animation: os-window-in var(--os-normal) both;
            }

            @keyframes os-window-in {
                from { opacity: 0; transform: scale(0.96); }
                to   { opacity: 1; transform: scale(1); }
            }

            main > section.app > div.app-head {
                width: 100%;
                height: 36px;

                display: flex;
                align-items: center;
                justify-content: space-between;

                padding: 0 12px;

                border-bottom: 1px solid var(--os-border-soft);
                cursor: default;
            }

            main > section.app > div.app-head > p {
                font-size: 13px;
                font-weight: 600;
                color: var(--os-text);
                letter-spacing: 0.1px;

                overflow: hidden;
                white-space: nowrap;
                text-overflow: ellipsis;
            }

            main > section.app > div.app-head > div.app-head-buttons {
                display: flex;
                align-items: center;
                gap: 8px;
                flex: 0 0 auto;
                margin-left: 12px;
            }

            main > section.app > div.app-head > div.app-head-buttons > .rounded {
                cursor: pointer;
                transition: transform var(--os-fast), filter var(--os-fast);
            }

            main > section.app > div.app-head > div.app-head-buttons > .rounded:hover {
                transform: scale(1.15);
                filter: brightness(1.1);
            }

            main > section.app > div.app-head > div.app-head-buttons > .rounded.is-disabled {
                opacity: 0.35;
                cursor: not-allowed;
            }

            main > section.app > div.app-head > div.app-head-buttons > .rounded.is-disabled:hover {
                transform: none;
                filter: none;
            }

            div.rounded {
                width: 12px !important;
                min-width: 12px;

                height: 12px !important;
                min-height: 12px;

                border-radius: 999px;

                display: flex;
                align-items: center;
                justify-content: center;

                font-size: 8px;
                line-height: 1;
                color: transparent;
            }

            div.rounded.red    { background-color: var(--os-close); }
            div.rounded.yellow { background-color: var(--os-min); }
            div.rounded.green  { background-color: var(--os-max); }

            .app-head-buttons:hover > .rounded.red::after    { content: "×"; color: rgba(0, 0, 0, 0.55); }
            .app-head-buttons:hover > .rounded.yellow::after { content: "–"; color: rgba(0, 0, 0, 0.55); }
            .app-head-buttons:hover > .rounded.green::after  { content: "+"; color: rgba(0, 0, 0, 0.55); }
            .app-head-buttons:hover > .rounded.is-disabled::after { content: ""; }

            main > section.app > div.app-main {
                width: 100%;
                height: calc(100% - 36px);

                position: relative;
                top: 0;
                left: 0;
            }

            section.app > div.app-main > * {
                position: absolute;
                border-radius: 0 0 var(--os-radius-lg) var(--os-radius-lg);
            }

            section.app > div.app-main > div.app-resize {
                width: 16px;
                height: 16px;

                position: absolute;
                bottom: 0;
                right: 0;
                top: auto;
                left: auto;

                z-index: 10; /* Doit passer au-dessus de .app-data (z-index: 1) */
                cursor: se-resize;

                background: linear-gradient(135deg, transparent 55%, var(--os-border) 55%, var(--os-border) 65%, transparent 65%, transparent 75%, var(--os-border) 75%, var(--os-border) 85%, transparent 85%);
                border-radius: 0 0 var(--os-radius-lg) 0;
                transition: background var(--os-fast);
            }

            section.app > div.app-main > div.app-resize:hover {
                background-color: var(--os-accent-soft);
                z-index: 11;
            }

            section.app > div.app-main > div.app-data {
                width: calc(100% - 4px);
                height: calc(100% - 2px);

                top: 0;
                left: 2px;

                z-index: 1;

                background-color: var(--os-content-bg);
                overflow: hidden;
            }

            section.app > div.app-main > div.app-data > iframe {
                position: static;
                width: 100%;
                height: 100%;
                border: none;
            }

            /* ==========================================
               DOCK (ICÔNES DES APPLICATIONS OUVERTES)
               ========================================== */
            #footer-apps > div.app {
                position: relative;
                flex: 0 0 auto;

                min-height: 44px;
                min-width: 44px;
                width: auto;

                padding: 4px 10px;

                display: flex;
                align-items: center;
                justify-content: center;
                gap: 8px;

                background: var(--os-glass);
                border-radius: var(--os-radius-md);
                cursor: pointer;

                transition: transform var(--os-fast), background var(--os-fast);
            }

            #footer-apps > div.app:hover {
                background: var(--os-glass-strong);
                transform: translateY(-3px);
            }

            #footer-apps > div.app > * {
                pointer-events: none;
            }

            #footer-apps > div.app > div.app-icon {
                min-height: 28px;
                min-width: 28px;

                background-color: rgba(255, 255, 255, 0.08);
                background-position: center;
                background-size: cover;
                background-repeat: no-repeat;

                border-radius: var(--os-radius-sm);
            }

            #footer-apps > div.app > p {
                font-size: 12px;
                color: var(--os-text);
                white-space: nowrap;
                max-width: 120px;
                overflow: hidden;
                text-overflow: ellipsis;
            }

            #footer-apps > div.app.active {
                background: var(--os-accent-soft) !important;
            }

            #footer-apps > div.app.active::after {
                content: "";
                position: absolute;
                bottom: -5px;
                left: 50%;
                transform: translateX(-50%);
                width: 4px;
                height: 4px;
                border-radius: 999px;
                background: var(--os-accent);
            }

            /* Bouton "Démarrer" (icône à 9 points, façon lanceur d'applications) */
            footer > div.start-btn {
                flex: 0 0 auto;

                width: 40px;
                height: 40px;

                display: flex;
                justify-content: center;
                align-items: center;

                background: var(--os-glass);
                border-radius: var(--os-radius-md);

                cursor: pointer;
                color: var(--os-text);

                transition: background var(--os-fast), color var(--os-fast), transform var(--os-fast);
            }

            footer > div.start-btn:hover {
                background: var(--os-accent);
                color: #1a1206;
                transform: translateY(-2px);
            }

            /* Icône à 9 points dessinée avec un seul élément (technique box-shadow) */
            footer > div.start-btn > .grid-icon {
                width: 4px;
                height: 4px;
                border-radius: 999px;
                background: currentColor;
                box-shadow:
                    -7px -7px 0 currentColor,
                     0px -7px 0 currentColor,
                     7px -7px 0 currentColor,
                    -7px  0px 0 currentColor,
                     7px  0px 0 currentColor,
                    -7px  7px 0 currentColor,
                     0px  7px 0 currentColor,
                     7px  7px 0 currentColor;
            }

            /* ==========================================
               MENU DÉMARRER
               ========================================== */
            #start-menu {
                position: absolute;
                bottom: 8px;
                left: 10px;

                width: 300px;
                max-height: 60vh;

                display: flex;
                flex-direction: column;

                padding: 14px;

                background: var(--os-glass-strong);
                border: 1px solid var(--os-border);
                border-radius: var(--os-radius-lg);
                box-shadow: var(--os-shadow-menu);
                backdrop-filter: blur(var(--os-blur)) saturate(160%);
                -webkit-backdrop-filter: blur(var(--os-blur)) saturate(160%);

                z-index: 2000;

                opacity: 0;
                transform: translateY(12px) scale(0.98);
                pointer-events: none;
                transition: opacity var(--os-normal), transform var(--os-normal);
            }

            #start-menu.open {
                opacity: 1;
                transform: translateY(0) scale(1);
                pointer-events: auto;
            }

            #start-menu > h3 {
                color: var(--os-text);
                font-size: 13px;
                font-weight: 600;
                letter-spacing: 0.2px;
                margin-bottom: 8px;
                padding: 0 4px;
            }

            #start-menu-list {
                display: grid;
                grid-template-columns: repeat(3, 1fr);
                gap: 8px;
                padding: 4px 2px;
                overflow-y: auto;
            }

            #start-menu-list > .start-menu-item {
                display: flex;
                flex-direction: column;
                align-items: center;
                justify-content: center;
                gap: 6px;

                padding: 10px 4px;

                color: var(--os-text);
                text-align: center;
                cursor: pointer;
                border-radius: var(--os-radius-md);
                transition: background var(--os-fast), transform var(--os-fast);
            }

            #start-menu-list > .start-menu-item:hover {
                background: rgba(255, 255, 255, 0.12);
                transform: translateY(-2px);
            }

            #start-menu-list > .start-menu-item > .start-menu-item-icon {
                width: 38px;
                height: 38px;

                background-color: rgba(255, 255, 255, 0.08);
                background-size: cover;
                background-position: center;
                border-radius: var(--os-radius-sm);
                box-shadow: 0 4px 10px rgba(3, 6, 15, 0.35);
            }

            #start-menu-list > .start-menu-item > p {
                width: 100%;
                font-size: 11px;
                line-height: 1.25;

                overflow: hidden;
                white-space: nowrap;
                text-overflow: ellipsis;
            }

            /* ==========================================
               MENU CONTEXTUEL (CLIC DROIT)
               ========================================== */
            #context-menu {
                position: absolute;
                display: block;

                min-width: 150px;
                padding: 4px;

                background: var(--os-glass-strong);
                border: 1px solid var(--os-border);
                border-radius: var(--os-radius-md);
                box-shadow: var(--os-shadow-menu);
                backdrop-filter: blur(var(--os-blur)) saturate(160%);
                -webkit-backdrop-filter: blur(var(--os-blur)) saturate(160%);

                z-index: 2500;
                transform-origin: top left;

                opacity: 0;
                transform: scale(0.96);
                pointer-events: none;
                transition: opacity var(--os-fast), transform var(--os-fast);
            }

            #context-menu.open {
                opacity: 1;
                transform: scale(1);
                pointer-events: auto;
            }

            .context-menu-item {
                padding: 8px 10px;
                color: var(--os-text);
                font-size: 12.5px;
                cursor: pointer;
                border-radius: var(--os-radius-sm);
                transition: background var(--os-fast);
            }

            .context-menu-item:hover {
                background: rgba(255, 255, 255, 0.12);
            }

            /* ==========================================
               RACCOURCIS DU BUREAU
               ========================================== */
            .desktop-shortcut {
                position: absolute;
                width: 80px;
                height: 84px;

                display: flex;
                flex-direction: column;
                align-items: center;
                justify-content: center;
                gap: 6px;

                border-radius: var(--os-radius-md);
                cursor: pointer;
                color: white;
                text-shadow: 0 1px 3px rgba(0, 0, 0, 0.8);

                transition: background var(--os-fast), box-shadow var(--os-fast);
            }

            .desktop-shortcut:hover {
                background: var(--os-glass);
            }

            .desktop-shortcut.selected {
                background: var(--os-accent-soft);
                box-shadow: 0 0 0 2px var(--os-accent) inset;
            }

            .desktop-shortcut > .shortcut-icon {
                width: 40px;
                height: 40px;
                background-size: cover;
                background-position: center;
                border-radius: var(--os-radius-sm);
                box-shadow: 0 4px 10px rgba(3, 6, 15, 0.4);
            }

            .desktop-shortcut > p {
                font-size: 11px;
                text-align: center;
                word-break: break-word;
                line-height: 1.25;
            }

            /* ==========================================
               POPUP SYSTÈME
               ========================================== */
            .popup-overlay {
                position: absolute;
                inset: 0;

                display: flex;
                align-items: center;
                justify-content: center;

                background: rgba(3, 6, 15, 0.45);
                backdrop-filter: blur(6px);
                z-index: 10000;
            }

            .popup-box {
                min-width: 300px;
                max-width: 380px;

                background: var(--os-glass-strong);
                border: 1px solid var(--os-border);
                border-radius: var(--os-radius-lg);
                box-shadow: var(--os-shadow-menu);
                backdrop-filter: blur(var(--os-blur)) saturate(160%);
                overflow: hidden;

                animation: os-window-in var(--os-fast) both;
            }

            .popup-header {
                padding: 12px 16px;
                font-weight: 600;
                font-size: 14px;
                color: white;
            }

            .popup-header--info    { background: #3b82f6; }
            .popup-header--warning { background: #f59e0b; }
            .popup-header--error   { background: #ef4444; }

            .popup-body {
                padding: 18px 16px;
                color: var(--os-text);
                font-size: 13.5px;
                line-height: 1.5;
            }

            .popup-footer {
                padding: 10px 16px;
                display: flex;
                justify-content: flex-end;
                border-top: 1px solid var(--os-border-soft);
            }

            .popup-ok-btn {
                padding: 6px 18px;
                border: none;
                border-radius: var(--os-radius-sm);
                background: var(--os-accent);
                color: #1a1206;
                font-weight: 600;
                font-size: 12.5px;
                cursor: pointer;
                transition: filter var(--os-fast);
            }

            .popup-ok-btn:hover {
                filter: brightness(1.08);
            }

            .popup-cancel-btn {
                padding: 6px 18px;
                margin-right: 8px;

                border: 1px solid var(--os-border);
                border-radius: var(--os-radius-sm);

                background: transparent;
                color: var(--os-text);
                font-weight: 600;
                font-size: 12.5px;
                cursor: pointer;
                transition: background var(--os-fast);
            }

            .popup-cancel-btn:hover {
                background: rgba(255, 255, 255, 0.1);
            }

            .popup-input {
                width: 100%;
                margin-top: 12px;
                padding: 8px 10px;

                background: rgba(255, 255, 255, 0.06);
                border: 1px solid var(--os-border);
                border-radius: var(--os-radius-sm);

                color: var(--os-text);
                font-size: 13px;
                user-select: text;
            }

            /* ==========================================
               RESPONSIVE
               ========================================== */
            @media (max-width: 640px) {
                #start-menu {
                    width: min(280px, 90vw);
                    left: 8px;
                }

                .desktop-shortcut {
                    width: 68px;
                    height: 74px;
                }

                #footer-apps > div.app > p {
                    display: none;
                }
            }

            @media (prefers-reduced-motion: reduce) {
                * {
                    animation-duration: 0.001ms !important;
                    transition-duration: 0.001ms !important;
                }
            }

            /* Activée via config.SetAnimationsEnabled(false) */
            .os-no-animations * {
                animation-duration: 0.001ms !important;
                transition-duration: 0.001ms !important;
            }