/* ল্যান্ডিং পেজ মেইন ডিজাইন */
        * { box-sizing: border-box; margin: 0; padding: 0; font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; }
        body { background-color: #f0f2f5; color: #1c1e21; overflow-x: hidden; }
        
        /* Hero Section */
        .hero-section {
            background: linear-gradient(135deg, #075e54, #128c7e);
            color: white;
            padding: 50px 20px;
            text-align: center;
        }

        .profile-img {
            width: 130px;
            height: 130px;
            border-radius: 50%;
            border: 5px solid rgba(255,255,255,0.2);
            margin-bottom: 15px;
            object-fit: cover;
            box-shadow: 0 4px 15px rgba(0,0,0,0.2);
        }

        .hero-section h1 { font-size: 2.2rem; margin-bottom: 10px; }
        .hero-section p { font-size: 1rem; opacity: 0.9; max-width: 500px; margin: 0 auto 20px; line-height: 1.5; }

        /* Features Section */
        .features {
            display: flex;
            justify-content: center;
            gap: 15px;
            flex-wrap: wrap;
            margin-top: 20px;
        }

        .feature-card {
            background: rgba(255, 255, 255, 0.15);
            padding: 10px 20px;
            border-radius: 30px;
            backdrop-filter: blur(10px);
            font-size: 0.9rem;
            border: 1px solid rgba(255,255,255,0.1);
        }

        .cta-text {
            margin: 40px 15px 20px;
            font-weight: 600;
            font-size: 1.1rem;
            color: #075e54;
            text-align: center;
        }

        /* চ্যাট বক্স কন্টেইনার (Responsive) */
        .chat-container-wrapper {
            width: 95%;
            max-width: 450px;
            margin: 0 auto 40px;
            height: 550px;
            border-radius: 20px;
            overflow: hidden;
            box-shadow: 0 15px 40px rgba(0,0,0,0.15);
            background: #fff;
            display: flex;
            flex-direction: column;
        }

        /* চ্যাট বক্স ইন্টারনাল (আগের সব লজিক ঠিক রেখে) */
        .app-container { display: flex; flex-direction: column; height: 100%; width: 100%; background: #efeae2 url('https://user-images.githubusercontent.com/15075759/28719144-86dc0f70-73b1-11e7-911d-60d70fcded21.png') repeat; }
        .header { background-color: #075e54; color: white; padding: 12px 16px; display: flex; align-items: center; gap: 12px; }
        .header-avatar { width: 40px; height: 40px; border-radius: 50%; background: #eee; display: flex; justify-content: center; align-items: center; font-weight: bold; color: #075e54; font-size: 20px; }
        .header-info { flex: 1; }
        .header-info h3 { font-size: 16px; margin: 0; }
        .header-status { font-size: 12px; opacity: 0.8; }
        
        #chat-window { flex: 1; overflow-y: auto; padding: 15px; display: flex; flex-direction: column; gap: 10px; }
        .msg { max-width: 85%; padding: 8px 12px; border-radius: 10px; font-size: 14px; position: relative; line-height: 1.4; box-shadow: 0 1px 1px rgba(0,0,0,0.1); }
        .received { background-color: white; align-self: flex-start; border-top-left-radius: 0; }
        .sent { background-color: #dcf8c6; align-self: flex-end; border-top-right-radius: 0; }
        .timestamp { font-size: 9px; color: #999; display: block; text-align: right; margin-top: 4px; }
        .voice-btn { cursor: pointer; color: #075e54; margin-left: 5px; font-size: 16px; }

        .chat-footer { background: #f0f0f0; padding: 10px; display: flex; align-items: center; gap: 8px; border-top: 1px solid #ddd; }
        .input-box { flex: 1; border-radius: 25px; border: 1px solid #ddd; padding: 10px 15px; outline: none; font-size: 14px; }
        .send-btn { background: #075e54; color: white; border: none; width: 40px; height: 40px; border-radius: 50%; cursor: pointer; font-size: 18px; display: flex; align-items: center; justify-content: center; flex-shrink: 0; }
        .img-btn { cursor: pointer; font-size: 22px; color: #075e54; display: flex; align-items: center; }

        /* ল্যান্ডিং পেজ ফুটার */
        footer {
            background-color: #054d44;
            color: white;
            text-align: center;
            padding: 30px 20px;
            margin-top: 50px;
        }
        .footer-content p { font-size: 0.9rem; opacity: 0.8; margin-bottom: 10px; }
        .social-links { margin-top: 15px; }
        .social-links a { color: white; text-decoration: none; margin: 0 0; font-size: 1.2rem; opacity: 0.9; }
        .social-links a:hover { opacity: 1; text-decoration: underline; }

        /* Responsive Mobile Fixes */
        @media (max-width: 480px) {
            .hero-section h1 { font-size: 1.8rem; }
            .hero-section p { font-size: 0.9rem; }
            .chat-container-wrapper { height: 500px; width: 95%; margin-bottom: 30px; }
            .msg { max-width: 90%; }
        }