/*Stile Problema 1*/
        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            line-height: 1.6;
            margin: 0;
            padding: 0;
            background-color: #f8f9fa;
            color: #333;
        }
        .container {
            max-width: 95%;
            width: 1200px;
            margin: 0 auto;
            padding: 20px;
            background-color: white;
            box-shadow: 0 0 20px rgba(0,0,0,0.1);
            border-radius: 8px;
            margin-top: 30px;
            margin-bottom: 30px;
        }
        .header-box {
            width: 100%;
            border: 2px dashed #28a745;
            box-sizing: border-box;
            padding: 0;
            display: flex;
            justify-content: space-between;
            align-items: center;
            background-color: white;
            min-height: 60px;
            border-radius: 8px;
            margin-bottom: 25px;
            overflow: hidden;
        }
        .left-image,
        .right-image {
            max-height: 60px;
            height: auto;
            margin: 10px;
        }
        .problem-title {
            font-size: 1.8em;
            font-weight: bold;
            color: black;
            margin: 25px 0 15px 0;
            text-align: center;
            text-shadow: 1px 1px 2px rgba(0,0,0,0.1);
        }
        .main-page-title {
            font-size: 2.2em;
            font-weight: bold;
            text-align: center;
            margin-bottom: 30px;
        }
        .main-page-title .blue {
            color: #0000FF;
        }
        .main-page-title .red {
            color: #FF0000;
        }
        .separator {
            border: 0;
            height: 2px;
            background: linear-gradient(to right, transparent, #28a745, transparent);
            margin: 15px 0 25px 0;
        }
        .problem-text {
            font-weight: bold;
            margin-left: 8px;
            padding-left: 17px;
            margin-bottom: 25px;
            color: #2c3e50;
            font-size: 1.1em;
            line-height: 1.7;
        }
        .solution-container {
            display: none;
        }
        .solution {
            background-color: #f8f9fa;
            padding: 15px 15px 15px 25px;
            margin: 15px 0 15px 8px;
            border-left: 4px solid #0000FF;
            border-radius: 0 5px 5px 0;
            box-shadow: 0 2px 5px rgba(0,0,0,0.05);
            position: relative;
        }
        /* ---- Titoli h3 nelle soluzioni: verde, unica definizione ---- */
        .solution h3 {
            color: #28a745;
            margin-top: 15px;
            margin-bottom: 10px;
            font-size: 1.2em;
            border-bottom: none;
        }
        .solution-button {
            background-color: #a5d6a7;
            color: black;
            border: 2px solid #81c784;
            padding: 10px 20px;
            text-align: center;
            text-decoration: none;
            display: inline-block;
            font-size: 14px;
            margin: 8px 4px;
            cursor: pointer;
            border-radius: 25px;
            transition: all 0.3s ease !important;
            box-shadow: 0 2px 5px rgba(0,0,0,0.1);
            font-weight: 600;
        }
        .solution-button:hover {
            filter: brightness(92%);
            transform: translateY(-2px);
            box-shadow: 0 4px 8px rgba(0,0,0,0.15);
        }
        .footer button {
            background-color: #0000FF;
            color: white;
            border: 2px solid #0000CC;
            padding: 10px 20px;
            text-align: center;
            text-decoration: none;
            display: inline-block;
            font-size: 14px;
            margin: 8px 4px;
            cursor: pointer;
            border-radius: 25px;
            transition: all 0.3s ease;
            box-shadow: 0 2px 5px rgba(0,0,0,0.1);
            font-weight: 600;
        }
        .footer button:nth-child(1) {
            background-color: #1a237e;
            border: 2px solid #0d1a4b;
        }
        .footer button:nth-child(1):hover {
            background-color: #3949ab;
            border-color: #1a237e;
            box-shadow: 0 4px 12px rgba(26, 35, 126, 0.4);
            transform: translateY(-2px);
        }
        .footer button:nth-child(2) {
            background-color: #007bff;
            border: 2px solid #0056b3;
        }
        .footer button:nth-child(2):hover {
            background-color: #339aff;
            border-color: #007bff;
            box-shadow: 0 4px 12px rgba(0, 123, 255, 0.4);
            transform: translateY(-2px);
        }
        .footer button:nth-child(3) {
            background-color: #FFA500;
            border: 2px solid #CC8400;
        }
        .footer button:nth-child(3):hover {
            background-color: #ffb733;
            border-color: #FFA500;
            box-shadow: 0 4px 12px rgba(255, 165, 0, 0.4);
            transform: translateY(-2px);
        }
        h4 {
            color: #2c3e50;
            margin-top: 0;
            margin-bottom: 10px;
            font-size: 1.2em;
        }
        .graph {
            text-align: center;
            margin: 25px auto;
            padding: 15px;
            background-color: white;
            border-radius: 8px;
            box-shadow: 0 3px 10px rgba(0,0,0,0.08);
            border: 1px solid #e9ecef;
            max-width: 600px;
        }
        .MathJax {
            font-size: 1.1em;
            color: #2c3e50;
        }
        a {
            text-decoration: none;
        }
        .question {
            background-color: #f8f9fa;
            padding: 15px 15px 15px 25px;
            margin-left: 8px;
            border-radius: 8px;
            margin-bottom: 20px;
            border-left: 4px solid #6c757d;
            position: relative;
        }
        .question strong {
            color: #2c3e50;
        }
        .footer {
            text-align: center;
            margin-top: 40px;
            padding-top: 20px;
            border-top: 1px solid #e9ecef;
        }
        .footer button.stampa {
            background-color: #9C27B0 !important;
            border: 2px solid #7B1FA2 !important;
            color: white !important;
            padding: 10px 25px !important;
            cursor: pointer !important;
            border-radius: 20px !important;
            font-weight: bold !important;
            margin-top: 15px !important;
            margin-bottom: 15px !important;
            display: inline-block !important;
            transition: all 0.3s ease !important;
        }
        .footer button.stampa:hover {
            background-color: #BA68C8 !important;
            border-color: #9C27B0 !important;
            box-shadow: 0 4px 12px rgba(156, 39, 176, 0.4) !important;
            transform: translateY(-2px) !important;
        }
        .header-link {
            display: flex !important;
            justify-content: space-between;
            align-items: center;
            width: 100%;
            height: 100%;
            text-decoration: none;
            padding: 10px;
            box-sizing: border-box;
        }
        .header-link img {
            display: block;
            height: auto;
        }
        .btn-nascondi {
            background-color: #FF9800 !important;
            color: white !important;
            border: none !important;
            padding: 10px 25px !important;
            cursor: pointer !important;
            border-radius: 20px !important;
            font-size: 14px !important;
            font-weight: bold !important;
            display: inline-block !important;
            margin: 10px auto !important;
            transition: all 0.3s ease !important;
        }
        .btn-nascondi:hover {
            background-color: #E68A00 !important;
            box-shadow: 0 4px 8px rgba(0,0,0,0.3) !important;
            transform: translateY(-2px) !important;
        }
        .instruction-box {
            line-height: 1.5;
            color: #856404;
        }
        @media print {
            .btn-nascondi, .solution-button, .footer, .instruction-box, #btn-top {
                display: none !important;
            }
            .solution-container {
                display: block !important;
            }
        }
        /* ---- Bottone torna su ---- */
        #btn-top {
            position: fixed;
            bottom: 20px;
            right: 4px;
            background: #9C27B0;
            color: #fff;
            border: none;
            border-radius: 50%;
            width: 44px;
            height: 44px;
            font-size: 1.3rem;
            cursor: pointer;
            box-shadow: 0 4px 12px rgba(0,0,0,0.25);
            display: none;
            align-items: center;
            justify-content: center;
            z-index: 999;
            transition: background 0.2s;
        }
        #btn-top:hover { background: #7a00cc; }

        /* ---- Responsive mobile ---- */
        mjx-container, .MathJax_Display {
            overflow-x: auto;
            overflow-y: hidden;
            max-width: 100%;
        }
        .table-scroll {
            overflow-x: auto;
            -webkit-overflow-scrolling: touch;
        }
        @media (max-width: 480px) {
            .left-image,
            .right-image {
                max-height: 38px;
            }
            .header-link {
                justify-content: space-around;
                padding: 6px;
            }
            .footer button {
                display: block;
                width: 90%;
                margin: 6px auto;
            }
            .problem-text {
                font-size: 1em;
            }
        }