:root {
            --primary-color: #2563eb;
            --primary-dark: #1d4ed8;
            --secondary-color: #10b981;
            --secondary-dark: #059669;
            --background-dark: #0f172a;
            --background-darker: #020617;
            --background-light: #f8fafc;
            --text-dark: #e2e8f0;
            --text-light: #1e293b;
            --card-bg-dark: #1e293b;
            --card-bg-light: #ffffff;
            --nav-bg-dark: rgba(15, 23, 42, 0.95);
            --nav-bg-light: rgba(248, 250, 252, 0.95);
            --border-radius: 12px;
            --box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
            --transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
        }

        :root.light-mode {
            --primary-color: #10b981;
            --primary-dark: #059669;
            --secondary-color: #2563eb;
            --secondary-dark: #1d4ed8;
            --background-dark: #f8fafc;
            --background-light: #0f172a;
            --text-dark: #1e293b;
            --text-light: #e2e8f0;
            --card-bg-dark: #ffffff;
            --card-bg-light: #1e293b;
            --nav-bg-dark: rgba(248, 250, 252, 0.95);
            --nav-bg-light: rgba(15, 23, 42, 0.95);
        }

        body {
            background: var(--background-dark);
            color: var(--text-dark);
            font-family: 'Montserrat', sans-serif;
            line-height: 1.7;
            transition: background 0.5s, color 0.5s;
        }

        /* Typography */
        h1, h2, h3, h4, h5, h6 {
            font-family: 'Poppins', sans-serif;
            font-weight: 600;
            line-height: 1.3;
        }

        h2 {
            font-size: 2.5rem;
            background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
            -webkit-background-clip: text;
            background-clip: text;
            -webkit-text-fill-color: transparent;
            margin-bottom: 2rem;
            position: relative;
            display: inline-block;
        }

        h2::after {
            content: '';
            position: absolute;
            bottom: -10px;
            left: 0;
            width: 60px;
            height: 4px;
            background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
            border-radius: 2px;
        }

        h3 {
            font-size: 2rem;
            margin: 2.5rem 0 1.5rem;
            color: var(--text-dark);
        }

        h4 {
            font-size: 1.5rem;
            margin: 2rem 0 1rem;
        }

        p {
            font-size: 1.1rem;
            opacity: 0.9;
            margin-bottom: 1.5rem;
        }

        /* Custom Scrollbar */
        ::-webkit-scrollbar {
            width: 10px;
        }

        ::-webkit-scrollbar-track {
            background: var(--background-dark);
        }

        ::-webkit-scrollbar-thumb {
            background: var(--primary-color);
            border-radius: 5px;
        }

        /* Navbar */
        .navbar {
            background: var(--nav-bg-dark);
            backdrop-filter: blur(10px);
            box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
            padding: 1rem 0;
            transition: var(--transition);
        }

        .navbar-brand {
            font-weight: 700;
            font-size: 1.5rem;
            color: var(--text-dark);
            transition: color 0.3s;
            display: flex;
            align-items: center;
            gap: 10px;
        }

        .navbar-brand:hover {
            color: var(--primary-color);
        }

        .navbar-brand i {
            font-size: 1.3rem;
        }

        /* Feature Cards */
        .feature-section {
            margin: 3rem 0;
        }

        .feature-card {
            background: var(--card-bg-dark);
            border-radius: var(--border-radius);
            padding: 2rem;
            height: 100%;
            transition: var(--transition);
            border: 1px solid rgba(255, 255, 255, 0.05);
            box-shadow: var(--box-shadow);
        }

        .feature-card:hover {
            transform: translateY(-5px);
            box-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.2);
            border-color: var(--primary-color);
        }

        .feature-card i {
            font-size: 2.5rem;
            margin-bottom: 1.5rem;
            color: var(--primary-color);
            background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
            -webkit-background-clip: text;
            background-clip: text;
            -webkit-text-fill-color: transparent;
        }

        .feature-card h4 {
            font-weight: 600;
            margin-bottom: 1rem;
        }

        .feature-card p {
            opacity: 0.8;
        }

        /* Video Container - UPDATED */
        .video-container {
            position: relative;
            width: 100%;
            overflow: hidden;
            border-radius: var(--border-radius);
            box-shadow: var(--box-shadow);
            margin: 2rem 0;
            background: var(--card-bg-dark);
            padding: 1rem;
        }

        .video-wrapper {
            position: relative;
            width: 100%;
            height: 0;
            padding-bottom: 110%; /* Adjusted for Facebook post */
            overflow: hidden;
            border-radius: var(--border-radius);
        }

        .video-wrapper iframe {
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            border: none;
            opacity: 0;
            transition: opacity 0.4s ease;
        }

        .facebook-video.embed-ready iframe {
            opacity: 1;
        }

        .facebook-video.embed-ready .video-fallback {
            opacity: 0;
            pointer-events: none;
            transform: scale(0.98);
        }

        .video-fallback {
            position: absolute;
            inset: 0;
            z-index: 2;
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            gap: 0.7rem;
            padding: clamp(1rem, 4vw, 2rem);
            text-align: center;
            background:
                radial-gradient(circle at 20% 20%, rgba(16, 185, 129, 0.24), transparent 32%),
                radial-gradient(circle at 80% 70%, rgba(37, 99, 235, 0.22), transparent 34%),
                linear-gradient(145deg, rgba(15, 23, 42, 0.98), rgba(30, 41, 59, 0.96));
            color: #e2e8f0;
            transition: opacity 0.4s ease, transform 0.4s ease;
        }

        .light-mode .video-fallback {
            background:
                radial-gradient(circle at 20% 20%, rgba(16, 185, 129, 0.18), transparent 32%),
                radial-gradient(circle at 80% 70%, rgba(37, 99, 235, 0.16), transparent 34%),
                linear-gradient(145deg, rgba(248, 250, 252, 0.98), rgba(226, 232, 240, 0.96));
            color: #1e293b;
        }

        .signal-animation {
            position: relative;
            width: 112px;
            height: 112px;
            display: grid;
            place-items: center;
            margin-bottom: 0.2rem;
        }

        .signal-core,
        .signal-block,
        .signal-ring {
            position: absolute;
            border-radius: 50%;
        }

        .signal-core {
            width: 58px;
            height: 58px;
            display: grid;
            place-items: center;
            background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
            color: #ffffff;
            font-size: 1.7rem;
            box-shadow: 0 18px 35px rgba(37, 99, 235, 0.3);
            animation: signalPulse 2s ease-in-out infinite;
        }

        .signal-ring {
            inset: 18px;
            border: 2px solid rgba(16, 185, 129, 0.55);
            opacity: 0;
            animation: signalRing 2.4s ease-out infinite;
        }

        .ring-two {
            animation-delay: 0.45s;
        }

        .ring-three {
            animation-delay: 0.9s;
        }

        .signal-block {
            right: 9px;
            bottom: 14px;
            width: 34px;
            height: 34px;
            display: grid;
            place-items: center;
            background: #ef4444;
            color: #ffffff;
            border: 3px solid var(--card-bg-dark);
            font-size: 0.95rem;
            animation: blockPop 1.7s ease-in-out infinite;
        }

        .fallback-label {
            margin: 0;
            color: var(--secondary-color);
            font-size: 0.82rem;
            font-weight: 700;
            letter-spacing: 0.08em;
            opacity: 1;
            text-transform: uppercase;
        }

        .video-fallback h3 {
            margin: 0;
            max-width: 560px;
            font-size: clamp(1.35rem, 4vw, 2rem);
        }

        .video-fallback p:not(.fallback-label) {
            max-width: 620px;
            margin: 0;
            font-size: clamp(0.9rem, 2.4vw, 1rem);
            opacity: 0.86;
        }

        .fallback-link {
            display: inline-flex;
            align-items: center;
            gap: 0.5rem;
            margin-top: 0.2rem;
            padding: 0.7rem 1rem;
            border-radius: 8px;
            background: rgba(255, 255, 255, 0.1);
            color: inherit;
            font-weight: 700;
            text-decoration: none;
            border: 1px solid rgba(255, 255, 255, 0.16);
            transition: var(--transition);
        }

        .fallback-button {
            cursor: pointer;
            font-family: inherit;
        }

        .fallback-link:hover {
            color: #ffffff;
            background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
            transform: translateY(-2px);
        }

        .light-mode .fallback-link {
            background: rgba(37, 99, 235, 0.08);
            border-color: rgba(37, 99, 235, 0.36);
            box-shadow: 0 8px 20px rgba(15, 23, 42, 0.08);
        }

        .light-mode .fallback-link:hover {
            color: #ffffff;
            background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
            border-color: transparent;
        }

        @keyframes signalPulse {
            0%, 100% { transform: scale(1); }
            50% { transform: scale(1.08); }
        }

        @keyframes signalRing {
            0% { opacity: 0.75; transform: scale(0.7); }
            100% { opacity: 0; transform: scale(1.55); }
        }

        @keyframes blockPop {
            0%, 100% { transform: scale(1) rotate(0deg); }
            45% { transform: scale(1.1) rotate(-8deg); }
        }

        @media (prefers-reduced-motion: reduce) {
            .signal-core,
            .signal-ring,
            .signal-block {
                animation: none;
            }
        }

        .list-group-item{
            color: var(--text-dark);
        }

        /* Buttons */
        .btn-primary {
            background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
            border: none;
            border-radius: var(--border-radius);
            padding: 0.75rem 1.5rem;
            font-weight: 600;
            transition: var(--transition);
            box-shadow: var(--box-shadow);
        }

        .btn-primary:hover {
            background: linear-gradient(135deg, var(--primary-dark), var(--primary-color));
            transform: translateY(-2px);
            box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.2);
        }

        /* Floating Buttons */
        .floating-btn {
            position: fixed;
            bottom: 20px;
            right: 20px;
            display: flex;
            flex-direction: column;
            gap: 15px;
            z-index: 1000;
        }

        .back-to-top,
        .theme-toggle {
            width: 50px;
            height: 50px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            background: var(--primary-color);
            color: white;
            border: none;
            cursor: pointer;
            transition: var(--transition);
            box-shadow: var(--box-shadow);
        }

        .back-to-top:hover,
        .theme-toggle:hover {
            transform: translateY(-5px) scale(1.1);
            box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
        }

        .back-to-top {
            bottom: 85px;
        }

        /* Back Button */
        .back-button {
            position: fixed;
            bottom: 40px;
            left: 20px;
            background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
            color: white;
            border: none;
            border-radius: var(--border-radius);
            padding: 12px 24px;
            font-size: 1rem;
            font-weight: 600;
            cursor: pointer;
            transition: var(--transition);
            box-shadow: var(--box-shadow);
            display: flex;
            align-items: center;
            gap: 8px;
            z-index: 1000;
        }

        .back-button:hover {
            background: linear-gradient(135deg, var(--secondary-color), var(--primary-color));
            transform: translateY(-2px);
            box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.2);
        }

        /* Footer */
        footer {
            background: var(--background-darker);
            color: var(--text-dark);
            padding: 2rem 0;
            margin-top: 4rem;
            text-align: center;
            transition: background 0.5s, color 0.5s;
        }

        footer p {
            margin: 0;
            font-size: 0.9rem;
            opacity: 0.8;
        }
        .light-mode footer {
            background: #e2e8f0;
            color: var(--text-dark);
        }
        
        /* Animations */
        @keyframes fadeIn {
            from { opacity: 0; transform: translateY(20px); }
            to { opacity: 1; transform: translateY(0); }
        }

        .animate-fadeIn {
            animation: fadeIn 0.6s ease-out forwards;
        }

        .delay-100 { animation-delay: 0.1s; }
        .delay-200 { animation-delay: 0.2s; }
        .delay-300 { animation-delay: 0.3s; }
        .delay-400 { animation-delay: 0.4s; }
        .delay-500 { animation-delay: 0.5s; }

        /* Badge Styles */
        .badge {
            font-size: 0.8rem;
            padding: 0.5em 0.75em;
            border-radius: 20px;
            font-weight: 500;
            text-transform: uppercase;
            letter-spacing: 0.05em;
        }

        /* Technology Stack */
        .tech-stack {
            display: flex;
            gap: 1rem;
            flex-wrap: wrap;
            justify-content: center;
            margin: 2rem 0;
        }

        .tech-item {
            padding: 0.8rem 1.5rem;
            background: rgba(37, 99, 235, 0.1);
            border-radius: 30px;
            border: 1px solid var(--primary-color);
            display: flex;
            align-items: center;
            gap: 0.5rem;
        }

        /* Event Details */
        .event-details {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: 1.5rem;
            margin: 2rem 0;
        }

        .detail-card {
            background: var(--card-bg-dark);
            border-radius: var(--border-radius);
            padding: 1.5rem;
            text-align: center;
            box-shadow: var(--box-shadow);
            transition: var(--transition);
        }

        .detail-card:hover {
            transform: translateY(-5px);
            box-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.2);
        }

        .detail-card i {
            font-size: 2rem;
            margin-bottom: 1rem;
            color: var(--primary-color);
        }

        .detail-card h4 {
            margin-bottom: 0.5rem;
            font-weight: 600;
        }

        /* Quote Styles */
        .quote {
            border-left: 4px solid var(--primary-color);
            padding-left: 1.5rem;
            margin: 2rem 0;
            font-style: italic;
            opacity: 0.9;
        }

        /* Responsive Adjustments */
        @media (min-width: 992px) {
            .video-wrapper {
                padding-bottom: 74%; /* Better aspect ratio for desktop */
            }
        }

        @media (max-width: 768px) {
            h2 {
                font-size: 2rem;
            }
            
            h3 {
                font-size: 1.75rem;
            }
            
            .feature-card {
                padding: 1.5rem;
                margin-bottom: 1.5rem;
            }
            
            .back-button {
                bottom: 20px;
                left: 50%;
                transform: translateX(-50%);
                padding: 10px 20px;
            }

            .tech-stack {
                gap: 0.5rem;
            }

            .tech-item {
                padding: 0.5rem 1rem;
                font-size: 0.8rem;
            }
            
            .video-wrapper {
                padding-bottom: 70%; /* Better for mobile */
            }
            
            .event-details {
                grid-template-columns: 1fr;
            }
        }

        @media (max-width: 576px) {
            .video-wrapper {
                padding-bottom: 120%; /* Even better for very small screens */
            }
        }
        /* For tablet screens (landscape) */
@media (min-width: 768px) and (max-width: 991px) {
    .video-wrapper {
        padding-bottom: 80%; /* Optimal for tablets */
    }
}