* {
            box-sizing: border-box;
        }

        body {
           
            background-color: #610916;
            background-image: url('images/bg-texture.jpg');
            background-size: cover;
            background-position: center;
            background-repeat: no-repeat;
            background-attachment: fixed;
            background-blend-mode: multiply;

           
            color: #ffffff;
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            margin: 0;
            padding: 20px;
            min-height: 100vh;

           
            display: flex;
            justify-content: center;
            align-items: center;
        }

        
        .calc-balustrade-box {
            width: 100%;
            max-width: 650px;
            background: #1a1a1a;
            border: 2px solid #F5C71A;
            border-radius: 12px;
            padding: 30px;
            box-shadow: 0 10px 30px rgba(0,0,0,0.7);
            margin: auto;
        }

       
        .calc-balustrade-box h2 {
            color: #F5C71A;
            margin-top: 0;
            margin-bottom: 8px;
            text-align: center;
            font-size: 24px;
            text-transform: uppercase;
            letter-spacing: 1px;
        }

        .calc-subtitle {
            text-align: center;
            color: #aaaaaa;
            font-size: 14px;
            margin-bottom: 25px;
        }

        
        .calc-field-group {
            margin-bottom: 20px;
        }

        .calc-field-group label {
            display: block;
            margin-bottom: 8px;
            font-size: 14px;
            font-weight: 600;
            color: #dddddd;
        }

        .calc-field-group select,
        .calc-field-group input[type="number"] {
            width: 100%;
            padding: 12px;
            background-color: #2b2b2b;
            border: 1px solid #444444;
            border-radius: 6px;
            color: #ffffff;
            font-size: 15px;
            outline: none;
            transition: border-color 0.3s;
        }

        .calc-field-group select:focus,
        .calc-field-group input[type="number"]:focus {
            border-color: #F5C71A;
        }

        .calc-field-group select:disabled {
            opacity: 0.5;
            cursor: not-allowed;
        }

        
        .calc-row-flex {
            display: flex;
            gap: 15px;
        }

        .calc-col-flex {
            flex: 1;
        }

        
        .calc-checkbox-group {
            margin: 20px 0;
            padding: 14px;
            background: #242424;
            border-radius: 6px;
            border: 1px solid #333333;
        }

        .calc-checkbox-group label {
            display: flex;
            align-items: center;
            gap: 12px;
            cursor: pointer;
            font-size: 14px;
            color: #ffffff;
            user-select: none;
        }

        .calc-checkbox-group input[type="checkbox"] {
            width: 18px;
            height: 18px;
            accent-color: #F5C71A;
            cursor: pointer;
        }

        
        .calc-result-summary {
            background: linear-gradient(135deg, #7A0016 0%, #4a000e 100%);
            border: 1px solid #F5C71A;
            padding: 20px;
            border-radius: 8px;
            text-align: center;
            margin-top: 25px;
        }

        .calc-result-summary .label-text {
            display: block;
            font-size: 13px;
            text-transform: uppercase;
            color: #dddddd;
            margin-bottom: 5px;
            letter-spacing: 0.5px;
        }

        .calc-result-summary .price-value {
            font-size: 32px;
            font-weight: bold;
            color: #F5C71A;
        }

        .calc-disclaimer {
            font-size: 11px;
            color: #888888;
            margin-top: 20px;
            text-align: center;
            line-height: 1.4;
        }

       
        .btn-back-container {
            text-align: center;
            margin-top: 20px;
        }

        .btn-back {
            display: inline-block;
            color: #dddddd;
            text-decoration: none;
            font-size: 13px;
            transition: color 0.3s;
        }

        .btn-back:hover {
            color: #F5C71A;
        }

        
        @media (max-width: 480px) {
            .calc-row-flex {
                flex-direction: column;
                gap: 0;
            }
            .calc-balustrade-box {
                padding: 20px 15px;
            }
        }