.text-highlight {
        background: linear-gradient(135deg, var(--primary) 20%, var(--secondary) 100%);
        -webkit-background-clip: text; -webkit-text-fill-color: transparent;
    }

    /* MINI APPS */
    .mini-apps { display: grid; grid-template-columns: repeat(6, 1fr); gap: 10px; margin-top: 40px; }
    .app-item {
        display: flex; flex-direction: column; align-items: center; gap: 10px;
        cursor: pointer; transition: transform 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
    }
    .app-item:hover { transform: translateY(-12px) scale(1.05); }
    /* Accessibility: semantic quick-action controls */
    a.app-item, button.app-item { background: none; border: none; padding: 0; font: inherit; color: inherit; text-decoration: none; cursor: pointer; }
    button.app-item { appearance: none; -webkit-appearance: none; }

    
    .app-icon {
        width: 68px; height: 68px; border-radius: 22px;
        background: var(--glass-material); border: 1px solid var(--glass-border);
        display: flex; align-items: center; justify-content: center;
        font-size: 26px; color: var(--primary); 
        box-shadow: 0 15px 30px rgba(0,0,0,0.1);
        position: relative; overflow: hidden;
    }
    
    .app-item[data-accent="green"] .app-icon { color: var(--accent-green); }
    .app-item[data-accent="blue"] .app-icon { color: var(--accent-blue); }
    .app-item[data-accent="yellow"] .app-icon { color: var(--accent-yellow); }
    .app-item[data-accent="purple"] .app-icon { color: var(--accent-purple); }
    /* AI Styling */
    .app-item[data-accent="ai"] .app-icon { 
        background: linear-gradient(135deg, #1A1A1A, #000); 
        color: #fff;
        border: 1px solid rgba(255, 255, 255, 0.2);
    }
    .app-item[data-accent="ai"] .app-icon i {
        background: linear-gradient(to right, #4facfe 0%, #00f2fe 100%);
        -webkit-background-clip: text;
        -webkit-text-fill-color: transparent;
        font-size: 28px;
    }
    /* Heart/Matchmaker Styling */
    .app-item[data-accent="love"] .app-icon { 
        background: linear-gradient(135deg, #fff0f0, #ffe6e6); 
        color: #ff3366;
    }

    .app-icon::after {
        content: ''; position: absolute; top: -50%; left: -50%; width: 200%; height: 200%;
        background: linear-gradient(45deg, transparent, rgba(255,255,255,0.4), transparent);
        transform: rotate(45deg) translateY(-100%); transition: 0.5s;
    }
    .app-item:hover .app-icon::after { transform: rotate(45deg) translateY(100%); }
    .app-label { font-size: 0.75rem; font-weight: 600; color: var(--text-main); text-align: center; line-height: 1.2; }

    /* Calculator */
    .calc-box {
        padding: 32px; border-radius: 36px;
        transform: perspective(1000px) rotateY(-5deg) rotateX(5deg);
        box-shadow: var(--shadow-3d); transition: transform 0.1s linear; 
        border-top: 1px solid rgba(255,255,255,0.3);
    }
    /* HORIZONTAL OVERFLOW FIX (iOS/Safari): the 3D rotateY(-5deg) tilt makes
       the full-width calculator's corners project BEYOND the viewport, so the
       document becomes wider than the screen and vertical scrolling lets the
       page (and the fixed chatbot panel above it) drift left/right with an
       empty-background rubber-band. Desktop keeps the 3D look; mobile renders
       the calculator flat. !important also neutralizes the JS mousemove tilt
       inline style if a touch device synthesizes mouse events. */
    @media (max-width: 768px) {
        .calc-box { transform: none !important; }
    }
    
    .form-group { margin-bottom: 20px; }
    .form-label { font-size: 0.9rem; font-weight: 700; color: var(--text-sub); margin-bottom: 8px; display: block; }
    .form-input {
        width: 100%; padding: 1rem; border-radius: 18px; border: 1px solid var(--glass-border);
        background: var(--muted-bg); color: var(--text-main); font-size: 1rem; font-weight: 600;
        transition: 0.3s;
    }
    .form-input:focus { background: var(--surface); border-color: var(--primary); box-shadow: 0 0 0 4px rgba(255, 107, 0, 0.2); }

    /* --- 6. SECTIONS --- */
    .section { padding: 80px 0; }
    .section-bg { background: var(--muted-bg); }
    
    .content-block { max-width: 860px; margin: 0 auto; }
    .policy-content ul, .policy-content ol { padding-left: 20px; color: var(--text-sub); margin-bottom: 20px; }
    .policy-content li { margin-bottom: 10px; }
    .policy-content p { text-align: justify; }

    /* --- 7. FOOTER --- */
    .footer { margin-top: 40px; }
    .footer-box { padding: 70px 50px; border-radius: 48px; position: relative; overflow: hidden; }
    .footer-bg-glow {
        position: absolute; bottom: -50%; left: 50%; transform: translateX(-50%);
        width: 120%; height: 120%; background: radial-gradient(circle, var(--primary) 0%, transparent 60%);
        opacity: 0.08; pointer-events: none;
    }
    
    .footer-grid { display: grid; gap: 50px; z-index: 1; position: relative; grid-template-columns: repeat(4, 1fr); }
    
    .f-col h4 {
        font-size: 1.2rem; font-weight: 800; margin-bottom: 24px; color: var(--text-main);
        display: flex; align-items: center; gap: 10px;
    }
    
    .f-link {
        display: flex; align-items: center; gap: 12px; margin-bottom: 16px;
        color: var(--text-sub); font-weight: 500; transition: 0.3s; font-size: 1rem;
    }
    .f-link:hover { color: var(--primary); transform: translateX(8px); }
    
    .f-svg-box {
        width: 32px; height: 32px; border-radius: 10px;
        background: var(--muted-bg); border: 1px solid var(--glass-border);
        display: flex; align-items: center; justify-content: center; color: var(--text-main);
        transition: 0.3s; flex-shrink: 0;
    }
    .f-link:hover .f-svg-box { background: var(--primary); color: var(--text-on-primary); border-color: var(--primary); }

    .footer-contact-info {
        text-align: center; color: var(--text-sub); font-size: 0.95rem;
        display: flex; flex-direction: column; gap: 8px; align-items: center;
        margin-bottom: 16px;
    }
    .fc-item { margin: 0; display: flex; align-items: center; gap: 8px; justify-content: center; }
    .fc-row { display: flex; gap: 20px; flex-wrap: wrap; justify-content: center; }
    
    @media (max-width: 768px) {
        .fc-row { flex-direction: column; gap: 8px; }
    }

    .social-btn {
        width: 36px; height: 36px; border-radius: 50%; display: flex; align-items: center; justify-content: center;
        background: var(--muted-bg); color: var(--text-main); border: 1px solid var(--glass-border);
        font-size: 16px; transition: 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
    }
    .social-btn:hover { transform: translateY(-5px); color: #fff; border-color: transparent; }
    
    .social-fb:hover { background: #1877F2; }
    .social-ins:hover { background: linear-gradient(45deg, #f09433 0%, #e6683c 25%, #dc2743 50%, #cc2366 75%, #bc1888 100%); }
    .social-pin:hover { background: #BD081C; }
    .social-me:hover { background: #00A98F; }
    .social-tik:hover { background: #000000; }

    /* --- 8. ULTRA APP MINI (FLOATING ACTION BUTTON) --- */
    .ultra-fab-wrapper {
        position: fixed;
        bottom: 30px;
        left: 20px;
        z-index: 999;
        display: flex;
        flex-direction: column-reverse;
        align-items: center;
        gap: 12px;
    }

    .ultra-main-btn {
        width: 60px; height: 60px;
        border-radius: 50%;
        background: linear-gradient(135deg, var(--primary), #FF4500);
        color: #fff;
        border: none;
        display: flex; align-items: center; justify-content: center;
        font-size: 26px;
        cursor: pointer;
        box-shadow: 0 8px 30px rgba(255, 107, 0, 0.4);
        position: relative;
        z-index: 2;
        transition: transform 0.3s cubic-bezier(0.68, -0.55, 0.27, 1.55);
        animation: ultra-glow 2s infinite;
    }
    
    @keyframes ultra-glow {
        0% { box-shadow: 0 0 0 0 rgba(255, 107, 0, 0.7); transform: scale(1); }
        50% { transform: scale(1.05); }
        70% { box-shadow: 0 0 0 15px rgba(255, 107, 0, 0); }
        100% { box-shadow: 0 0 0 0 rgba(255, 107, 0, 0); transform: scale(1); }
    }
    
    @keyframes ultra-shake {
        0%, 100% { transform: rotate(0deg); }
        25% { transform: rotate(-10deg); }
        75% { transform: rotate(10deg); }
    }

    /* Apply shake on interval via JS or simpler hover/active */
    .ultra-main-btn.shaking {
        animation: ultra-shake 0.5s ease-in-out;
    }

    .ultra-main-btn i { transition: 0.3s; }
    .ultra-fab-wrapper.active .ultra-main-btn {
        transform: rotate(45deg);
        background: #333; /* Darken when open */
        box-shadow: 0 8px 30px rgba(0,0,0,0.3);
        animation: none; /* Stop pulsing when open */
    }

    .ultra-actions {
        position: absolute;
        bottom: 70px;
        left: 0;
        width: 60px;
        display: flex;
        flex-direction: column-reverse;
        gap: 12px;
        pointer-events: none;
    }

    .ultra-sub-btn {
        width: 50px; height: 50px;
        border-radius: 18px;
        background: var(--glass-material); /* Adaptive glass background */
        backdrop-filter: blur(15px);
        -webkit-backdrop-filter: blur(15px);
        border: 1px solid var(--glass-border);
        color: var(--text-main);
        display: flex; align-items: center; justify-content: center;
        font-size: 20px;
        box-shadow: 0 5px 15px rgba(0,0,0,0.1);
        cursor: pointer;
        opacity: 0;
        transform: translateY(20px) scale(0.8);
        transition: 0.3s cubic-bezier(0.68, -0.55, 0.27, 1.55);
        margin: 0 auto; /* Center in column */
        text-decoration: none;
        pointer-events: auto;
    }
    
    /* FEATURE 1: BACKTOP STYLE - Hidden by default at top */
    .u-backtop {
        display: none; 
    }
    .u-backtop.show {
        display: flex;
        animation: popInBtn 0.3s ease;
    }
    @keyframes popInBtn { from {transform:scale(0);} to {transform:scale(1);} }

    /* Active State: Fan out buttons */
    .ultra-fab-wrapper.active .ultra-sub-btn {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
    
    /* Staggered delay for "Spring" effect */
    .ultra-fab-wrapper.active .ultra-sub-btn:nth-child(1) { transition-delay: 0.05s; }
    .ultra-fab-wrapper.active .ultra-sub-btn:nth-child(2) { transition-delay: 0.1s; }
    .ultra-fab-wrapper.active .ultra-sub-btn:nth-child(3) { transition-delay: 0.15s; }
    .ultra-fab-wrapper.active .ultra-sub-btn:nth-child(4) { transition-delay: 0.2s; }
    .ultra-fab-wrapper.active .ultra-sub-btn:nth-child(5) { transition-delay: 0.25s; }

    .ultra-sub-btn::after {
        content: attr(data-tooltip);
        position: absolute;
        left: 60px;
        background: rgba(0,0,0,0.8);
        color: white;
        padding: 4px 10px;
        border-radius: 8px;
        font-size: 12px;
        white-space: nowrap;
        opacity: 0;
        visibility: hidden;
        transition: 0.2s;
        pointer-events: none;
    }
    .ultra-sub-btn:hover::after {
        opacity: 1; visibility: visible; left: 65px;
    }

    .u-zalo { color: #0068FF; }
    .u-wa { color: #25D366; }
    .u-map { color: #FFB800; }
    .u-phone { color: var(--primary); }

    /* --- AI MODAL STYLES --- */
    .ai-modal-overlay {
        position: fixed; inset: 0; background: rgba(0,0,0,0.7); 
        z-index: 2000; opacity: 0; visibility: hidden; 
        transition: 0.3s; backdrop-filter: blur(5px);
    }
    .ai-modal {
        position: fixed; top: 50%; left: 50%; width: 90%; max-width: 500px;
        height: 70vh; max-height: 700px;
        transform: translate(-50%, -40%) scale(0.95);
        background: var(--surface);
        border: 1px solid var(--glass-border);
        border-radius: 32px;
        box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
        display: flex; flex-direction: column; overflow: hidden;
        z-index: 2001; opacity: 0; visibility: hidden;
        transition: 0.4s cubic-bezier(0.16, 1, 0.3, 1);
    }
    .ai-modal.active { opacity: 1; visibility: visible; transform: translate(-50%, -50%) scale(1); }
    .ai-modal-overlay.active { opacity: 1; visibility: visible; }

    .ai-header {
        padding: 20px; border-bottom: 1px solid var(--glass-border);
        display: flex; justify-content: space-between; align-items: center;
        background: var(--muted-bg);
    }
    .ai-header h3 { margin: 0; font-size: 1.1rem; display: flex; align-items: center; gap: 8px; }
    .ai-close { cursor: pointer; background: none; border: none; font-size: 24px; color: var(--text-sub); transition: 0.2s; }
    .ai-close:hover { color: var(--text-main); transform: rotate(90deg); }

    .ai-chat-area {
        flex: 1; overflow-y: auto; padding: 20px;
        display: flex; flex-direction: column; gap: 16px;
        background: var(--bg-body);
    }
    
    .chat-msg {
        max-width: 85%; padding: 12px 16px; border-radius: 20px;
        font-size: 0.95rem; line-height: 1.5;
        position: relative; animation: popIn 0.3s ease-out;
    }
    @keyframes popIn { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }

    .msg-bot {
        align-self: flex-start;
        background: var(--surface); border: 1px solid var(--glass-border);
        border-bottom-left-radius: 4px; color: var(--text-main);
    }
    .msg-user {
        align-self: flex-end;
        background: linear-gradient(135deg, var(--primary), #FF8800);
        color: white; border-bottom-right-radius: 4px;
        box-shadow: 0 4px 15px rgba(255, 107, 0, 0.2);
    }
    .msg-bot strong { color: var(--primary); }

    .ai-input-area {
        padding: 16px; background: var(--surface); border-top: 1px solid var(--glass-border);
        display: flex; gap: 10px;
    }
    .ai-input {
        flex: 1; padding: 12px 16px; border-radius: 24px; border: 1px solid var(--glass-border);
        background: var(--muted-bg); color: var(--text-main);
    }
    .ai-send {
        width: 46px; height: 46px; border-radius: 50%; border: none;
        background: var(--text-main); color: var(--surface);
        display: flex; align-items: center; justify-content: center; cursor: pointer;
        transition: 0.2s;
    }
    .ai-send:hover { transform: scale(1.1); }