body {
            padding: 20px;
            background-color: #f8f9fa;
            min-height: 100vh;
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            color: #2c3e50;
        }

        .main-container {
            background: white;
            border-radius: 12px;
            box-shadow: 0 2px 20px rgba(0, 0, 0, 0.08);
            padding: 32px;
            border: 1px solid #e9ecef;
            max-width: 1200px;
            margin: 0 auto;
        }

        .title-section {
            text-align: center;
            margin-bottom: 40px;
            color: #2c3e50;
        }

        .title-section h1 {
            font-size: 2.5rem;
            font-weight: 700;
            margin-bottom: 8px;
            color: #2c3e50;
        }

        .title-section p {
            font-size: 1.1rem;
            color: #6c757d;
            font-weight: 400;
        }

        .card {
            border: 1px solid #e9ecef;
            border-radius: 8px;
            box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
            transition: box-shadow 0.2s ease;
            margin-bottom: 20px;
        }

        .card:hover {
            box-shadow: 0 4px 16px rgba(0, 0, 0, 0.1);
        }

        .card-header {
            font-weight: 600;
            border-radius: 8px 8px 0 0 !important;
            border-bottom: 1px solid #e9ecef;
            background-color: #f8f9fa !important;
            color: #495057 !important;
        }

        .btn-primary {
            background-color: #495057;
            border: 1px solid #495057;
            border-radius: 6px;
            padding: 12px 24px;
            font-weight: 500;
            transition: all 0.2s ease;
        }

        .btn-primary:hover {
            background-color: #343a40;
            border-color: #343a40;
            transform: none;
            box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
        }

        .form-control {
            border-radius: 6px;
            border: 1px solid #ced4da;
            padding: 12px 16px;
            transition: all 0.2s ease;
            font-size: 16px;
        }

        .form-control:focus {
            border-color: #6c757d;
            box-shadow: 0 0 0 3px rgba(108, 117, 125, 0.1);
        }

        .fuel-icon {
            color: #495057;
            margin-right: 8px;
        }

        .result-card {
            background: linear-gradient(135deg, #495057, #6c757d);
            color: white;
            border: none;
        }

        .result-card .card-header {
            background: rgba(255, 255, 255, 0.1) !important;
            color: white !important;
            border-bottom: 1px solid rgba(255, 255, 255, 0.2);
        }

        .result-value {
            font-size: 2rem;
            font-weight: 700;
            color: #ffc107;
            margin-bottom: 4px;
        }

        .result-label {
            font-size: 0.875rem;
            opacity: 0.9;
            margin-bottom: 0;
        }

        .calculator-section {
            border-left: 4px solid #495057;
            padding-left: 20px;
        }

        .money-input {
            background: linear-gradient(135deg, #28a745, #20c997);
            color: white;
            border: none;
        }

        .money-input .form-control {
            background: rgba(255, 255, 255, 0.1);
            border: 1px solid rgba(255, 255, 255, 0.3);
            color: white;
        }

        .money-input .form-control::placeholder {
            color: rgba(255, 255, 255, 0.7);
        }

        .money-input .form-control:focus {
            background: rgba(255, 255, 255, 0.15);
            border-color: rgba(255, 255, 255, 0.5);
            color: white;
            box-shadow: 0 0 0 3px rgba(255, 255, 255, 0.1);
        }

        .money-input .input-group-text {
            background: rgba(255, 255, 255, 0.2);
            border: 1px solid rgba(255, 255, 255, 0.3);
            color: white;
            font-weight: bold;
        }

        .optional-field {
            background: #f8f9fa;
            border-radius: 8px;
            padding: 15px;
            margin: 15px 0;
            border-left: 3px solid #6c757d;
        }

        .optional-label {
            color: #6c757d;
            font-size: 0.875rem;
            margin-bottom: 8px;
        }

        .range-display {
            text-align: center;
            padding: 20px;
            background: linear-gradient(135deg, #17a2b8, #20c997);
            color: white;
            border-radius: 8px;
            margin: 20px 0;
        }

        .range-number {
            font-size: 3rem;
            font-weight: 900;
            line-height: 1;
            text-shadow: 0 2px 4px rgba(0,0,0,0.3);
        }

        .range-unit {
            font-size: 1.2rem;
            opacity: 0.9;
            margin-top: 5px;
        }

        .fuel-gauge {
            background: #e9ecef;
            height: 25px;
            border-radius: 15px;
            overflow: hidden;
            margin: 15px 0;
            position: relative;
        }

        .fuel-level {
            height: 100%;
            background: linear-gradient(90deg, #28a745, #20c997);
            transition: width 0.8s ease;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 12px;
            font-weight: bold;
            color: white;
        }

        .comparison-card {
            background: #fff3cd;
            border: 1px solid #ffeaa7;
            border-radius: 8px;
            padding: 15px;
            margin: 15px 0;
        }

        .comparison-item {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 8px 0;
            border-bottom: 1px solid #f1c40f;
        }

        .comparison-item:last-child {
            border-bottom: none;
        }

        .trip-type-selector {
            background: #e8f4fd;
            border-radius: 8px;
            padding: 15px;
            margin-bottom: 20px;
            border: 2px solid #b8daff;
        }

        .trip-type-option {
            cursor: pointer;
            padding: 10px 15px;
            border-radius: 6px;
            margin: 5px;
            transition: all 0.2s ease;
            border: 2px solid transparent;
        }

        .trip-type-option:hover {
            background: rgba(255, 255, 255, 0.5);
        }

        .trip-type-option.active {
            background: #007bff;
            color: white;
            border-color: #0056b3;
        }

        .round-trip-display {
            background: linear-gradient(135deg, #fd7e14, #ffc107);
            color: white;
            border-radius: 8px;
            padding: 15px;
            margin: 15px 0;
            text-align: center;
        }

        .round-trip-note {
            background: #fff3cd;
            border: 1px solid #ffeaa7;
            border-radius: 6px;
            padding: 10px;
            margin: 10px 0;
            font-size: 0.9rem;
        }

        .driving-conditions {
            background: #f0f8ff;
            border-radius: 8px;
            padding: 15px;
            margin: 15px 0;
            border-left: 3px solid #007bff;
        }

        .style-option {
            cursor: pointer;
            padding: 10px 15px;
            border-radius: 6px;
            margin: 5px;
            transition: all 0.2s ease;
            border: 1px solid #e9ecef;
            background: white;
            text-align: center;
        }

        .style-option:hover {
            background: #f8f9fa;
        }

        .style-option.active {
            background: #28a745;
            color: white;
            border-color: #1e7e34;
        }

        .efficiency-adjustment {
            background: #fff3cd;
            border-radius: 6px;
            padding: 10px;
            margin: 10px 0;
            font-size: 0.9rem;
            text-align: center;
        }

        .form-range {
            cursor: pointer;
        }

        .road-mix-total {
            font-size: 0.9rem;
            text-align: center;
            padding: 8px;
            border-radius: 4px;
            margin-top: 10px;
        }

        .road-mix-valid {
            background: #d1edff;
            color: #0066cc;
        }

        .road-mix-invalid {
            background: #ffe6e6;
            color: #cc0000;
        }

        @media (max-width: 991.98px) {
            .main-container {
                max-width: 100%;
            }
        }

        @media (max-width: 575.98px) {
            body { padding: 15px; }
            .main-container { padding: 20px; }
            .title-section h1 { font-size: 1.8rem; }
            .title-section { margin-bottom: 30px; }
            .result-value { font-size: 1.5rem; }
            .range-number { font-size: 2.5rem; }
            .calculator-section { padding-left: 15px; }
        }