:root {
            --bg-cream: #F9F7F1;
            --text-dark: #1A1A1A;
            --text-gray: #4A4A4A;
            --bg-dark: #090E17;
            --text-light: #F0F0F0;
            --cement-gray: #8A96A8;
            --accent-gold: #D67B28; /* Tinh chỉnh lại màu gold trầm hơn */
            --accent-blue: #3172A3;
            --accent-red: #8B0000;
        }

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

        body {
            font-family: 'Inter', sans-serif;
            background-color: var(--bg-cream);
            color: var(--text-dark);
            overflow-x: hidden;
            -webkit-font-smoothing: antialiased;
            overscroll-behavior: none;
        }

        h1, h2, h3 { 
            font-family: 'Montserrat', sans-serif; 
            line-height: 1.3; 
            font-weight: 800;
        }
        
        p { 
            font-weight: 300; 
            line-height: 1.8; 
            font-size: 1.25rem; 
            margin-bottom: 2rem; 
        }

        .num-1 { font-size: 1.15em; font-weight: 700; }
        .unit-m { font-size: 0.9em; font-weight: 600; }
        
        .text-container {
            max-width: 760px;
            margin: 0 auto;
            padding: 15vh 20px;
            position: relative;
            z-index: 10;
        }

        .dark-theme { background-color: var(--bg-cream); color: var(--text-dark); }
        .dark-theme p { color: var(--text-gray); }

        .section-title {
            font-family: 'Montserrat', sans-serif;
            font-size: 3rem;
            font-weight: 900;
            text-transform: uppercase;
            letter-spacing: -0.5px;
            margin: 6rem 0 3rem 0;
            position: relative;
            padding-bottom: 1rem;
            background: linear-gradient(135deg, var(--accent-blue) 0%, var(--accent-gold) 100%);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            display: block;
        }
        
        .section-title::after {
            content: '';
            position: absolute;
            bottom: 0; left: 0; width: 80px; height: 6px;
            border-radius: 3px;
            background: linear-gradient(90deg, var(--accent-blue), var(--accent-gold));
        }
        
        .section-title.dark-text { 
            background: linear-gradient(135deg, #1A1A1A 0%, var(--accent-blue) 100%);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
        }
        .section-title.dark-text::after { background: linear-gradient(90deg, #1A1A1A, var(--accent-blue)); }

        .drop-cap:first-letter {
            font-family: 'Playfair Display', serif;
            font-size: 5rem;
            font-weight: 800;
            float: left;
            margin-top: -0.1em;
            margin-right: 0.1em;
            color: var(--accent-gold);
            line-height: 1;
        }

        .info-box {
            background: #FFFFFF;
            border: 1px solid rgba(214, 123, 40, 0.2);
            border-left: 5px solid var(--accent-gold);
            padding: 3rem;
            margin: 4rem 0;
            box-shadow: 0 15px 35px rgba(0,0,0,0.05);
            border-radius: 8px;
        }
        .info-box p:last-child { margin-bottom: 0; }

        html.lenis { height: auto; }
        .lenis.lenis-smooth { scroll-behavior: auto; }
        .lenis.lenis-smooth [data-lenis-prevent] { overscroll-behavior: contain; }
        .lenis.lenis-stopped { overflow: hidden; }

        .scene-opening { height: 450vh; position: relative; background-color: #F8F5F0; }
        .opening-sticky { position: sticky; top: 0; height: 100vh; width: 100%; display: flex; align-items: center; justify-content: center; overflow: hidden; perspective: 1200px; }
        .room-bg-container { position: absolute; top: 0; left: 0; width: 100%; height: 100%; z-index: 1; display: flex; align-items: center; justify-content: center; transform-origin: 50% 65%; }
        .room-svg { width: 100vw; height: 100vh; object-fit: cover; }
        .opening-bg { position: absolute; top: 0; left: 0; width: 100%; height: 100%; background-color: rgba(253, 250, 246, 0.5); backdrop-filter: blur(4px); opacity: 0; z-index: 2; }
        
        .center-group { position: absolute; bottom: 15%; left: 50%; transform: translateX(-50%); z-index: 5; display: flex; flex-direction: column; align-items: center; transform-style: preserve-3d; }
        .couple-wrapper { position: relative; z-index: 15; margin-bottom: -20px; }
        .family-photo { width: 280px; height: 280px; object-fit: cover; border-radius: 50%; border: 4px solid var(--accent-gold); box-shadow: 0 15px 35px rgba(0,0,0,0.4), 0 0 30px rgba(212, 175, 55, 0.3); display: block; background-color: transparent; }

        .floor-1m2-wrapper { position: relative; width: 250px; height: 250px; transform-style: preserve-3d; transform: rotateX(72deg) rotateZ(45deg) scale(1); z-index: 4; }
        .floor-layer { position: absolute; top: 0; left: 0; width: 100%; height: 100%; display: flex; align-items: center; justify-content: center; font-weight: 600; font-size: 1.2rem; color: rgba(255,255,255,0.9); border: 1px solid rgba(255,255,255,0.3); opacity: 0; backface-visibility: hidden; text-align: center; padding: 10px; }
        
        .layer-wood-top { background: #fffdf5; border: 2px solid #e2d5c3; opacity: 1 !important; box-shadow: 0 0 30px rgba(255,255,255,0.8), inset 0 0 20px rgba(0,0,0,0.05); z-index: 10; background-image: linear-gradient(45deg, #f5f0e6 25%, transparent 25%, transparent 75%, #f5f0e6 75%, #f5f0e6), linear-gradient(45deg, #f5f0e6 25%, transparent 25%, transparent 75%, #f5f0e6 75%, #f5f0e6); background-size: 60px 60px; background-position: 0 0, 30px 30px; }
        .layer-wood-top::before, .layer-wood-top::after { position: absolute; font-family: 'Inter', sans-serif; font-size: 16px; font-weight: 800; color: #fff; background: rgba(0,0,0,0.3); padding: 2px 8px; border-radius: 4px; white-space: nowrap; }
        .layer-wood-top::before { content: '← 1m →'; bottom: -30px; left: 50%; transform: translateX(-50%); }
        .layer-wood-top::after { content: '← 1m →'; right: -55px; top: 50%; transform: translateY(-50%) rotate(-90deg); }

        .layer-glue, .layer-cement, .layer-steel, .layer-stone, .layer-sand, .layer-earth { background-image: repeating-linear-gradient(45deg, rgba(0,0,0,0.15) 0, rgba(0,0,0,0.15) 1.5px, transparent 1.5px, transparent 7px), repeating-linear-gradient(-45deg, rgba(0,0,0,0.15) 0, rgba(0,0,0,0.15) 1.5px, transparent 1.5px, transparent 7px); }
        .layer-glue { background-color: #e9c46a; color: #222;} .layer-cement { background-color: #94a3b8; color: #111;}
        .layer-steel { background-color: #334155; border: 2px solid #64748b; background-image: repeating-linear-gradient(45deg, rgba(255,255,255,0.15) 0, rgba(255,255,255,0.15) 1.5px, transparent 1.5px, transparent 7px), repeating-linear-gradient(-45deg, rgba(255,255,255,0.15) 0, rgba(255,255,255,0.15) 1.5px, transparent 1.5px, transparent 7px); }
        .layer-stone { background-color: #475569; background-image: repeating-linear-gradient(45deg, rgba(255,255,255,0.15) 0, rgba(255,255,255,0.15) 1.5px, transparent 1.5px, transparent 7px), repeating-linear-gradient(-45deg, rgba(255,255,255,0.15) 0, rgba(255,255,255,0.15) 1.5px, transparent 1.5px, transparent 7px); }
        .layer-sand { background-color: #f4a261; color: #111;}
        .layer-earth { background-color: #451a03; color: #fff; background-image: repeating-linear-gradient(45deg, rgba(255,255,255,0.15) 0, rgba(255,255,255,0.15) 1.5px, transparent 1.5px, transparent 7px), repeating-linear-gradient(-45deg, rgba(255,255,255,0.15) 0, rgba(255,255,255,0.15) 1.5px, transparent 1.5px, transparent 7px); }

        .question-overlay { position: absolute; top: 0; left: 0; width: 100%; height: 100%; display: flex; align-items: center; justify-content: center; z-index: 20; pointer-events: none; }
        .big-question { font-family: 'Playfair Display', serif; font-size: 3.5rem; font-weight: 800; color: #1A1A1A; text-align: center; line-height: 1.3; background: rgba(255, 255, 255, 0.7); backdrop-filter: blur(15px); padding: 3rem 4rem; border-radius: 24px; border: 1px solid rgba(255,255,255,0.9); box-shadow: 0 20px 50px rgba(0,0,0,0.08); transform: scale(0.2); opacity: 0; }
        .hero-1m2 { display: block; margin: 0.5rem 0; } .hero-num { font-size: 1.25em; font-weight: 900; line-height: 1; } .hero-unit { font-size: 0.8em; font-weight: 800; margin-left: 2px; }

        .horizontal-container { width: 100vw; height: 100vh; background-color: #FCF6ED; overflow: hidden; position: relative; }
        .horizontal-wrapper { display: flex; height: 100%; width: fit-content; }
        .h-slide { width: 100vw; height: 100vh; display: flex; flex-direction: column; align-items: center; justify-content: center; padding: 0 10vw; position: relative; }
        .h-slide-content { text-align: center; z-index: 2; }
        .h-slide-title { font-family: 'Montserrat', sans-serif; font-size: 3.2rem; margin-bottom: 1.5rem; font-weight: 900; text-transform: uppercase; background: linear-gradient(135deg, var(--accent-blue) 0%, #4CAF50 100%); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }
        .h-slide-text { font-size: 1.5rem; color: var(--text-gray); max-width: 600px; }
        .h-slide-bg-text { position: absolute; font-size: 15vw; font-weight: 900; color: rgba(0,0,0,0.03); z-index: 1; top: 50%; transform: translateY(-50%); white-space: nowrap; }

        .scene-40-industries { height: 250vh; background-color: #F2E8D8; border-top: 1px solid rgba(0,0,0,0.05); }
        .tree-sticky { position: sticky; top: 0; height: 100vh; display: flex; flex-direction: column; align-items: center; justify-content: center; overflow: hidden; }
        .tree-title { position: absolute; top: 10%; font-family: 'Montserrat', sans-serif; font-size: 2.2rem; font-weight: 900; text-transform: uppercase; background: linear-gradient(135deg, var(--accent-blue) 0%, var(--accent-gold) 100%); -webkit-background-clip: text; -webkit-text-fill-color: transparent; opacity: 0; text-align: center; padding: 0 20px; }
        .tree-container { position: relative; width: 800px; height: 600px; }
        .tree-center { position: absolute; top: 50%; left: 50%; transform: translate(-50%, -50%); width: 100px; height: 100px; background: var(--accent-gold); color: #FFF; display: flex; align-items: center; justify-content: center; font-weight: 800; font-size: 1.5rem; border-radius: 50%; z-index: 10; }
        .tree-svg { position: absolute; top: 0; left: 0; width: 100%; height: 100%; z-index: 1; }
        .tree-line { fill: none; stroke: rgba(0,0,0,0.1); stroke-width: 2; }
        .tree-node { position: absolute; background: #FFF; border: 1px solid rgba(0,0,0,0.1); color: var(--text-dark); padding: 8px 16px; border-radius: 20px; font-size: 0.9rem; transform: translate(-50%, -50%); z-index: 5; opacity: 0; }
        .node-main { font-size: 1.2rem; font-weight: 600; color: #FFF; border-color: var(--accent-blue); background: var(--accent-blue); }

        .interaction-hint { text-align: center; color: var(--cement-gray); margin-bottom: 2rem; font-size: 0.95rem; font-style: italic; }
        .flip-cards-container { display: flex; gap: 2rem; margin: 4rem 0; perspective: 1000px; }
        .flip-card { flex: 1; height: 350px; position: relative; cursor: pointer; }
        .flip-card-inner { position: absolute; width: 100%; height: 100%; transition: transform 0.8s cubic-bezier(0.4, 0, 0.2, 1); transform-style: preserve-3d; border-radius: 12px; }
        .flip-card:hover .flip-card-inner { transform: rotateY(180deg); }
        .flip-card-front, .flip-card-back { position: absolute; width: 100%; height: 100%; backface-visibility: hidden; -webkit-backface-visibility: hidden; border-radius: 12px; padding: 2.5rem; display: flex; flex-direction: column; justify-content: center; }
        .flip-card-front { background: #FFF; border: 1px solid rgba(214, 123, 40, 0.3); align-items: center; text-align: center; box-shadow: 0 10px 30px rgba(0,0,0,0.05); }
        .flip-card-front h3 { color: var(--accent-gold); font-size: 2rem; margin-top: 1rem; }
        .flip-card-back { background: var(--accent-blue); color: white; transform: rotateY(180deg); border: none; box-shadow: 0 15px 35px rgba(0,0,0,0.15); }
        .flip-card-back p { color: #FFF; font-size: 1.15rem; line-height: 1.6; font-weight: 300; }
        .flip-card-back ul { list-style: none; margin-top: 1rem; }
        .flip-card-back ul li { margin-bottom: 1rem; font-size: 1.1rem; font-weight: 300; position: relative; padding-left: 1.5rem; }
        .flip-card-back ul li::before { content: '→'; position: absolute; left: 0; color: #F3D360; font-weight: bold; }

        .scene-chart { background-color: var(--bg-cream); padding: 10vh 20px; }
        .chart-section { background: #fff; border-radius: 16px; padding: 3rem; margin: 3rem 0; box-shadow: 0 20px 40px rgba(0,0,0,0.05); }
        .chart-title { text-align: center; font-family: 'Montserrat', sans-serif; font-size: 1.6rem; font-weight: 900; text-transform: uppercase; color: var(--accent-blue); margin-bottom: 2rem; letter-spacing: 0.5px; }
        .bar-group { display: flex; flex-direction: column; gap: 0.5rem; margin-bottom: 1.5rem; }
        .bar-group-title { font-weight: 800; font-size: 1.1rem; color: var(--text-gray); }
        .bar-row { display: flex; align-items: center; gap: 1rem; }
        .bar-label { width: 180px; text-align: right; font-weight: 600; color: var(--text-dark); font-size: 1rem; }
        .bar-track { flex: 1; height: 35px; background: rgba(0,0,0,0.05); border-radius: 6px; overflow: hidden; position: relative; }
        .bar-fill { height: 100%; width: 0%; display: flex; align-items: center; padding-right: 15px; justify-content: flex-end; color: white; font-weight: 600; border-radius: 6px; min-width: fit-content; padding-left: 15px; box-shadow: inset -5px 0 10px rgba(0,0,0,0.1); }
        .fill-23 { background: #8A96A8; } .fill-24 { background: #3A506B; } .fill-25 { background: var(--accent-red); }
        .fill-vin { background: #8B0000; } .fill-sun { background: #B22222; } .fill-nh { background: #CD5C5C; } .fill-ctx { background: #F08080; }

        .scene-numbers-scroll { height: 350vh; background-color: #EBE3D7; color: var(--text-dark); position: relative; z-index: 10; }
        .numbers-scroll-sticky { position: sticky; top: 0; height: 100vh; width: 100%; display: flex; align-items: center; justify-content: center; overflow: hidden; perspective: 1000px; }
        .numbers-scroll-title { position: absolute; top: 15%; font-family: 'Montserrat', sans-serif; font-size: 2.8rem; font-weight: 900; text-transform: uppercase; background: linear-gradient(135deg, var(--accent-gold) 0%, #E9C46A 100%); -webkit-background-clip: text; -webkit-text-fill-color: transparent; text-align: center; width: 100%; padding: 0 20px; z-index: 20; }
        .n-slides-container { position: relative; width: 100%; height: 400px; display: flex; align-items: center; justify-content: center; transform-style: preserve-3d; z-index: 15; }
        .n-slide-3d { position: absolute; width: 100%; text-align: center; padding: 0 20px; backface-visibility: hidden; }
        .n-stat { font-family: 'Playfair Display', serif; font-size: 7rem; font-weight: 800; color: var(--accent-gold); margin-bottom: 1rem; line-height: 1; text-shadow: 0 10px 30px rgba(0,0,0,0.05); }
        .n-desc { font-size: 1.5rem; color: var(--text-gray); max-width: 600px; margin: 0 auto; font-weight: 400; line-height: 1.5; }

        .scene-outro { min-height: 80vh; background: var(--bg-cream); color: var(--text-dark); display: flex; align-items: center; justify-content: center; text-align: center; position: relative; overflow: hidden; padding: 10vh 20px; border-top: 1px solid rgba(0,0,0,0.05); }
        .outro-content { max-width: 750px; margin: 0 auto; position: relative; z-index: 2; }
        .outro-p { font-family: 'Playfair Display', serif; font-size: 1.6rem; line-height: 1.8; opacity: 0; color: var(--text-gray); font-style: italic; font-weight: 300; margin-bottom: 1.5rem; }
        .outro-highlight { font-size: 1.8rem; font-weight: 800; color: var(--accent-gold); font-style: normal; font-family: 'Playfair Display', serif; }

        .fade-text { opacity: 0; transform: translateY(30px); }
        .budget-title { text-align: center; color: var(--text-dark); font-size: 2rem; margin-top: 4rem; }

        @media (max-width: 768px) {
            /* Typo & Spacing */
            p { font-size: 1.05rem; line-height: 1.6; margin-bottom: 1.25rem; }
            .section-title { font-size: 1.8rem; margin: 3rem 0 1.5rem 0; }
            .text-container { padding: 6vh 15px; }
            .info-box { padding: 1.5rem; margin: 2rem 0; }
            .budget-title { font-size: 1.35rem; margin-top: 2rem; margin-bottom: 1rem; white-space: normal; line-height: 1.4; }
            .interaction-hint { display: none; } /* Ẩn dòng chữ "Di chuột..." vì Mobile đã trải phẳng */
            
            /* Opening Scene */
            .center-group { transform: translateX(-50%) scale(0.65); bottom: 20%; transform-origin: bottom center; }
            .big-question { font-size: 1.5rem; padding: 1.5rem 1rem; width: 90%; border-radius: 16px; }
            .hero-num { font-size: 1.5em; }

            /* Horizontal & Tree */
            .h-slide-title { font-size: 1.8rem; margin-bottom: 1rem; } 
            .h-slide-text { font-size: 1.05rem; }
            .h-slide-bg-text { font-size: 22vw; opacity: 0.04; }
            .tree-container { transform: scale(0.4); transform-origin: top center; margin-top: 3rem; }
            .tree-title { font-size: 1.3rem; top: 5%; }

            /* GIẢI QUYẾT TRIỆT ĐỂ LỖI FLIP CARD TRÊN MOBILE: Chuyển thành dạng Card xếp chồng nguyên khối */
            .flip-cards-container { flex-direction: column; gap: 1.5rem; perspective: none; margin: 1.5rem 0 3rem 0; }
            .flip-card { height: auto; cursor: default; }
            .flip-card:hover .flip-card-inner { transform: none; } /* Vô hiệu hóa lật */
            .flip-card-inner { position: relative; transform: none !important; transition: none; display: flex; flex-direction: column; box-shadow: 0 8px 25px rgba(0,0,0,0.08); border-radius: 16px; border: 1px solid rgba(214, 123, 40, 0.3); overflow: hidden; }
            .flip-card-front, .flip-card-back { position: relative; width: 100%; height: auto; transform: none !important; padding: 1.5rem; display: block; backface-visibility: visible; -webkit-backface-visibility: visible; }
            
            /* Giao diện mặt trước (Tiêu đề) */
            .flip-card-front { background: #FFF; border-radius: 16px 16px 0 0; border: none; border-bottom: 1px dashed rgba(214, 123, 40, 0.3); text-align: center; box-shadow: none; padding-bottom: 1rem; }
            .flip-card-front h3 { font-size: 1.4rem; margin-top: 0.5rem; color: var(--accent-gold); }
            .flip-card-front div { font-size: 3rem !important; }
            
            /* Giao diện mặt sau (Nội dung) */
            .flip-card-back { background: #FAFAFA; border-radius: 0 0 16px 16px; color: var(--text-dark); padding-top: 1.25rem; box-shadow: none; text-align: left; }
            .flip-card-back p { color: var(--text-gray) !important; font-size: 1rem !important; margin-bottom: 0; }
            .flip-card-back ul { margin-top: 0; }
            .flip-card-back ul li { color: var(--text-dark); font-size: 1rem; margin-bottom: 0.75rem; }
            .flip-card-back ul li::before { color: var(--accent-gold); }

            /* GIẢI QUYẾT TRIỆT ĐỂ LỖI CHART TRÊN MOBILE: Tối ưu UI Cột ngang hiển thị Full-width */
            .scene-chart { padding: 6vh 15px; }
            .chart-section { padding: 1.5rem; margin: 1.5rem 0; border-radius: 12px; }
            .chart-title { font-size: 1.15rem; margin-bottom: 1.5rem; }
            .bar-group { margin-bottom: 1.25rem; }
            .bar-group-title { font-size: 1rem; margin-bottom: 0.5rem; }
            .bar-row { flex-direction: column; align-items: flex-start; gap: 0.3rem; margin-bottom: 0.5rem; }
            .bar-label { width: 100%; text-align: left; font-size: 0.95rem; line-height: 1.2; }
            .bar-track { height: 30px; width: 100%; border-radius: 4px; }
            .bar-fill { font-size: 0.85rem; border-radius: 4px; }

            /* Numbers & Outro */
            .numbers-scroll-title { font-size: 2rem; top: 8%; }
            .n-stat { font-size: 4rem; } 
            .n-desc { font-size: 1.1rem; padding: 0 10px; }
            .n-slides-container { height: 300px; }
            .outro-p { font-size: 1.2rem; } 
            .outro-highlight { font-size: 1.35rem; }
        }
        
        .source-link { color: var(--accent-gold); text-decoration: none; font-weight: 600; transition: color 0.3s ease; }
        .source-link:hover { color: var(--accent-blue); text-decoration: underline; }