body {
            font-family: Arial, sans-serif;
            background-color: #121212;
            color: #ffffff;
            text-align: center;
            margin: 0;
            padding: 0;
        }
        .logo {
            position: fixed;
            top: 20%; 
            left: 0%;
            width: 250px;
            height: auto;
            z-index: -1;
        }
        .logo2 {
            position: fixed;
            top: 20%;
            right: 0%;
            width: 250px;
            height: auto;
            z-index: -1;
        }
        .container {
            max-width: 900px;
            margin: auto;
            padding: 50px 20px;
        }
        h1 {
            font-size: 2.5em;
            margin-bottom: 1px;
            margin-top: 1px;
            color: white;
        }
        h3 {
            font-size: 1.5em;
            margin-bottom: 5px;
            margin-top: 30px;
            color: #1e88e5;
        }
        .back-button {
            display: inline-block;
            margin-top: 50px;
            margin-bottom: 90px;
            background-color: #1e88e5;
            color: white;
            padding: 10px 20px;
            border-radius: 5px;
            text-decoration: none;
            font-size: 1.1em;
        }
        .back-button:hover {
            background-color: #1565c0;
        }
        footer {
            background-color: #121212;
            color: silver;
            text-align: center;
            padding: 10px;
            border-top: 2px solid #1565c0;
            box-shadow: 0px -5px 5px rgba(0,0,0,0.5);
            position: fixed;
            bottom: 0;
            width: 100%;
        }
        
        .folders-container {
            display: flex;
            flex-wrap: wrap;
            gap: 20px;
            justify-content: center;
			
        }
        .folder {
            width: calc(50% - 10px);
            text-align: center;
        }
        
        .pdf-list {
            list-style-type: none;
            padding: 0;
            margin: 10px 0 0;
        }
        .pdf-list li {
            margin: 5px 0;
        }
        .pdf-list a {
            color: silver;
            text-decoration: none;
            font-size: 1.2em;
        }
        .pdf-list a:hover {
            color: #1e88e5;
        }