    <style>
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        body {
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
            background: #f4f7fc; /* Quasi bianco con un leggero tocco blu/grigio */
            min-height: 100vh;
            color: #1a2a3a;
            
        }

        .container {
            max-width: 1400px;
            margin: 0 auto;
        }

        .header {
            text-align: center;
            color: #1e3c72;
            margin-bottom: 30px;
        }

        .header h1 {
            font-size: 2.5rem;
            margin-bottom: 10px;
            text-shadow: 1px 1px 2px rgba(0,0,0,0.05);
            background: linear-gradient(135deg, #1e3c72 0%, #2a5298 100%);
            background-clip: text;
            -webkit-background-clip: text;
            color: transparent;
        }

        .header p {
            font-size: 1.1rem;
            color: #4a6a8a;
        }

        .card {
            background: white;
            border-radius: 20px;
            padding: 25px;
            margin-bottom: 25px;
            box-shadow: 0 8px 20px rgba(0,0,0,0.08);
            border: 1px solid #e8edf2;
        }

        .input-group {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
            gap: 20px;
            margin-bottom: 25px;
        }

        .input-field {
            display: flex;
            flex-direction: column;
        }

        .input-field label {
            font-weight: 600;
            margin-bottom: 8px;
            color: #1e3c72;
        }

        .input-field input, .input-field select {
            padding: 12px;
            border: 2px solid #dce3ec;
            border-radius: 10px;
            font-size: 16px;
            transition: all 0.3s;
            background: white;
        }

        .input-field input:focus, .input-field select:focus {
            outline: none;
            border-color: #2a5298;
            box-shadow: 0 0 0 3px rgba(42, 82, 152, 0.1);
        }

        button {
            background: linear-gradient(135deg, #1e3c72 0%, #2a5298 100%);
            color: white;
            border: none;
            padding: 12px 30px;
            border-radius: 10px;
            font-size: 16px;
            font-weight: 600;
            cursor: pointer;
            transition: transform 0.2s, box-shadow 0.2s;
            width: 100%;
        }

        button:hover {
            transform: translateY(-2px);
            box-shadow: 0 6px 14px rgba(30, 60, 114, 0.25);
        }

        .method-selector {
            display: flex;
            gap: 10px;
            margin-bottom: 20px;
            flex-wrap: wrap;
        }

        .method-checkbox {
            display: flex;
            align-items: center;
            gap: 8px;
            background: #f0f4f9;
            padding: 8px 15px;
            border-radius: 10px;
            cursor: pointer;
            transition: all 0.3s;
            color: #1e3c72;
            font-weight: 500;
            border: 1px solid #e0e6ed;
        }

        .method-checkbox:hover {
            background: #e6edf5;
            transform: translateY(-1px);
        }

        .method-checkbox input {
            cursor: pointer;
            accent-color: #2a5298;
        }

        .table-container {
            overflow-x: auto;
            margin-top: 20px;
        }

        .zones-table {
            width: 100%;
            border-collapse: collapse;
            font-size: 0.9rem;
            min-width: 800px;
        }

        .zones-table th {
            background: linear-gradient(135deg, #1e3c72 0%, #2a5298 100%);
            color: white;
            padding: 15px 10px;
            font-weight: 600;
            position: sticky;
            top: 0;
            z-index: 10;
        }

        .zones-table td {
            padding: 12px 10px;
            border-bottom: 1px solid #eef2f7;
            vertical-align: top;
            color: #1e2e3e;
            background-color: white;
        }

        .zones-table tr:hover td {
            background-color: #f8fafd;
        }

        .zone-label {
            font-weight: bold;
            font-size: 1rem;
            color: #1e3c72;
        }

        .zone-subtitle {
            font-size: 0.8rem;
            color: #6b7f9a;
            margin-top: 3px;
        }

        .intensity-badge {
            display: inline-block;
            padding: 3px 8px;
            border-radius: 20px;
            font-size: 0.7rem;
            font-weight: bold;
            margin-right: 5px;
        }

        .z1-badge { background: #4CAF50; color: white; }
        .z2-badge { background: #8BC34A; color: #1e2a3a; }
        .z3-badge { background: #FFC107; color: #1e2a3a; }
        .z4-badge { background: #FF9800; color: white; }
        .z5-badge { background: #F44336; color: white; }
        .z6-badge { background: #9C27B0; color: white; }
        .z7-badge { background: #E91E63; color: white; }

        .pace-value {
            font-family: 'Courier New', monospace;
            font-weight: bold;
            color: #2a5298;
        }

        .duration {
            font-size: 0.8rem;
            color: #7a8ea8;
        }

        .scientific-name {
            font-style: italic;
            color: #2a5298;
            font-size: 0.85rem;
        }

        .legend {
            display: flex;
            flex-wrap: wrap;
            gap: 15px;
            margin-top: 20px;
            padding: 15px;
            background: #f8fafd;
            border-radius: 10px;
            color: #1e2a3a;
            border: 1px solid #e8edf2;
        }

        .legend-item {
            display: flex;
            align-items: center;
            gap: 8px;
            font-size: 0.85rem;
        }

        .method-badge {
            display: inline-block;
            padding: 2px 6px;
            border-radius: 4px;
            font-size: 0.7rem;
            font-weight: bold;
            margin-left: 5px;
        }

        .daniels-badge { background: #1e3c72; color: white; }
        .friel-badge { background: #e67e22; color: white; }
        .seiler-badge { background: #27ae60; color: white; }
        .coggan-badge { background: #8e44ad; color: white; }

        @media (max-width: 768px) {
            body {
                padding: 15px;
            }
            .header h1 {
                font-size: 1.8rem;
            }
            .zones-table {
                font-size: 0.8rem;
            }
            .zones-table td, .zones-table th {
                padding: 8px 5px;
            }
            .card {
                padding: 18px;
            }
        }