/* --- RESET & BASIC SETUP --- */
        * { box-sizing: border-box; margin: 0; padding: 0; }
        body {
            font-family: 'Mulish', sans-serif;
            background-color: #000;
            color: #fff;
            overflow: hidden; 
            height: 100dvh; 
            width: 100vw;
            -webkit-font-smoothing: antialiased;
        }

        /* --- CONTAINER --- */
        .story-container {
            width: 100%;
            height: 100dvh; 
            max-width: 550px; 
            margin: 0 auto;
            position: relative;
            background: #111;
            box-shadow: 0 0 50px rgba(0,0,0,0.9);
        }

        /* --- SCROLL WRAPPER --- */
        .slides-wrapper {
            display: flex;
            width: 100%;
            height: 100%;
            overflow-x: hidden; 
            overflow-y: hidden;
            scroll-behavior: smooth;
        }

        /* --- SLIDE SETUP --- */
        .slide {
            flex: 0 0 100%; 
            height: 100%;
            position: relative;
            overflow: hidden;
        }

        .slide-bg {
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            object-fit: cover; 
            z-index: 1;
            transition: transform 15s ease-out; /* Slow zoom effect */
            transform-origin: center;
        }

        .slide.active .slide-bg {
            transform: scale(1.12);
        }

        /* --- OVERLAYS --- */
        .overlay {
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: linear-gradient(to bottom, 
                rgba(0,0,0,0.1) 0%, 
                rgba(0,0,0,0.3) 30%, 
                rgba(0,0,0,0.85) 85%,
                rgba(0,0,0,0.95) 100%);
            z-index: 2;
            pointer-events: none; 
        }

        /* --- CONTENT BOX --- */
        .content {
            position: absolute;
            bottom: 30px; 
            left: 50%;
            transform: translateX(-50%);
            width: 92%; 
            max-height: 80%; 
            z-index: 10;
            background: rgba(0, 0, 0, 0.45); 
            backdrop-filter: blur(10px);
            -webkit-backdrop-filter: blur(10px);
            padding: 20px;
            border-radius: 20px;
            border: 1px solid rgba(255, 215, 0, 0.15);
            opacity: 0;
            transform: translate(-50%, 40px);
            transition: all 0.8s cubic-bezier(0.25, 0.46, 0.45, 0.94) 0.2s;
            display: flex;
            flex-direction: column;
            overflow-y: auto;
            box-shadow: 0 10px 30px rgba(0,0,0,0.5);
        }

        .slide.active .content {
            opacity: 1;
            transform: translate(-50%, 0);
        }

        /* --- TYPOGRAPHY --- */
        h2 {
            font-family: 'Playfair Display', serif;
            font-size: 24px; 
            line-height: 1.3;
            margin-bottom: 15px;
            font-weight: 800;
            color: #FFD700; /* Vàng kim */
            text-align: center;
            text-shadow: 2px 2px 4px rgba(0,0,0,0.8);
            padding-bottom: 10px;
            border-bottom: 1px solid rgba(255, 215, 0, 0.3);
        }

        .long-title { font-size: 20px; }

        p {
            font-size: 15.5px;
            line-height: 1.6;
            color: #F0F0F0;
            text-align: justify; 
            margin-bottom: 12px;
            text-shadow: 1px 1px 2px rgba(0,0,0,0.8);
        }

        p:last-child { margin-bottom: 0; }

        /* Scrollbar */
        .content::-webkit-scrollbar { width: 3px; }
        .content::-webkit-scrollbar-track { background: transparent; }
        .content::-webkit-scrollbar-thumb { background: rgba(255, 215, 0, 0.4); border-radius: 3px; }

        /* --- PROGRESS UI --- */
        .progress-container {
            position: absolute; top: 15px; left: 10px; right: 10px;
            display: flex; gap: 4px; z-index: 50;
        }
        .progress-item {
            flex: 1; height: 3px; background: rgba(255,255,255,0.3);
            border-radius: 2px; overflow: hidden;
        }
        .progress-fill {
            height: 100%; width: 0%; background: #FFD700;
            transition: width 0.3s linear;
        }

        /* --- CONTROLS --- */
        .top-controls { position: absolute; top: 30px; right: 15px; z-index: 60; }
        .control-btn { 
            background: rgba(0,0,0,0.4); border: 1px solid rgba(255,255,255,0.3); 
            color: #fff; width: 36px; height: 36px; border-radius: 50%; 
            display: flex; align-items: center; justify-content: center; 
            backdrop-filter: blur(5px); cursor: pointer; 
        }

        .nav-btn {
            position: absolute; top: 50%; transform: translateY(-50%);
            z-index: 20; background: transparent; color: #fff; border: none;
            width: 60px; height: 80%; display: flex; align-items: center;
            justify-content: center; cursor: pointer; outline: none;
        }
        .nav-prev { left: 0; justify-content: flex-start; padding-left: 10px; }
        .nav-next { right: 0; justify-content: flex-end; padding-right: 10px; }
        .nav-btn i { 
            opacity: 0; transition: opacity 0.3s; font-size: 28px; 
            filter: drop-shadow(0 0 5px rgba(0,0,0,0.8));
        }
        .nav-btn:active i { opacity: 0.8; }
        @media (hover: hover) { .nav-btn:hover i { opacity: 0.8; } }

        /* =========================================
           HIỆU ỨNG ĐẶC BIỆT THEO YÊU CẦU
           ========================================= */
        
        /* 1. Slide 2: Mây bay và đom đóm/sao lấp lánh */
        .clouds-layer {
            position: absolute; top: -5%; left: 0; width: 200%; height: 50%;
            background: url('https://www.transparenttextures.com/patterns/stardust.png');
            opacity: 0.6; z-index: 3; pointer-events: none;
            animation: driftClouds 40s linear infinite;
            mix-blend-mode: screen;
        }
        @keyframes driftClouds { 0% { transform: translateX(0); } 100% { transform: translateX(-50%); } }

        .sparkles-container { position: absolute; top: 0; left: 0; width: 100%; height: 100%; z-index: 4; pointer-events: none; }
        .sparkle {
            position: absolute; width: 3px; height: 3px; background: #fff;
            border-radius: 50%; box-shadow: 0 0 8px #FFD700, 0 0 15px #FFD700;
            animation: twinkle var(--duration) ease-in-out infinite alternate;
        }
        @keyframes twinkle { 0% { opacity: 0.2; transform: scale(0.8); } 100% { opacity: 1; transform: scale(1.5); } }

        /* 2. Slide 3 & 4: Chữ rơi xuống nhịp nhàng */
        .stagger-list { display: flex; flex-direction: column; gap: 12px; margin-top: 10px; }
        .stagger-item {
            opacity: 0; transform: translateY(-20px);
            transition: all 0.6s cubic-bezier(0.175, 0.885, 0.32, 1.275);
            background: rgba(255, 255, 255, 0.05);
            padding: 12px; border-radius: 10px; border-left: 3px solid #FFD700;
        }
        .slide.active .stagger-item { opacity: 1; transform: translateY(0); }
        .slide.active .stagger-item:nth-child(1) { transition-delay: 0.6s; }
        .slide.active .stagger-item:nth-child(2) { transition-delay: 1.0s; }
        .slide.active .stagger-item:nth-child(3) { transition-delay: 1.4s; }

        /* Slide 3: Con số phóng to, đổi màu */
        .big-number {
            display: inline-block; font-size: 1.3em; font-weight: bold;
            color: #FF7F50; /* Màu cam san hô nổi bật */
            font-family: 'Playfair Display', serif;
            transform: scale(1); transition: transform 0.8s cubic-bezier(0.175, 0.885, 0.32, 1.275);
            text-shadow: 0 0 10px rgba(255, 127, 80, 0.4);
        }
        .slide.active .big-number { transform: scale(1.2); margin: 0 6px;}

        /* Slide 5: Icons thay chấm tròn */
        .icon-item {
            display: flex; align-items: flex-start; gap: 12px; margin-bottom: 15px;
        }
        .icon-item i {
            color: #FFD700; font-size: 20px; margin-top: 4px; width: 25px; text-align: center;
        }
        .icon-item p { margin-bottom: 0; }
        .icon-item strong { color: #FFD700; font-family: 'Playfair Display', serif; font-size: 17px; display: block; margin-bottom: 3px;}