.percentage-tool-section {
            background-color: #fff;
            padding: 30px;
            border-radius: 10px;
            box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
            margin-bottom: 30px;
        }
        .percentage-tool-section h1 {
            text-align: center;
            color: #2c3e50;
            margin-bottom: 25px;
            font-size: 2.2rem;
        }
        .calculator-tabs {
            display: flex;
            margin-bottom: -1px; /* To overlap border */
            flex-wrap: wrap;
        }
        .tab-link {
            padding: 12px 20px;
            cursor: pointer;
            border: 1px solid #dee2e6;
            border-bottom: none;
            background-color: #f8f9fa;
            border-radius: 8px 8px 0 0;
            margin-right: 5px;
            font-weight: 600;
            color: #495057;
            transition: background-color 0.3s, color 0.3s;
        }
        .tab-link:hover {
            background-color: #e9ecef;
        }
        .tab-link.active {
            background-color: #fff;
            color: #3498db;
            border-color: #dee2e6;
            border-bottom: 1px solid #fff;
            position: relative;
            z-index: 2;
        }
        .calculator-content-wrapper {
            border: 1px solid #dee2e6;
            padding: 25px;
            border-radius: 0 8px 8px 8px;
            background-color: #fff;
        }
        .tab-content {
            display: none;
        }
        .tab-content.active {
            display: block;
            animation: fadeIn 0.5s;
        }
        @keyframes fadeIn {
            from { opacity: 0; transform: translateY(10px); }
            to { opacity: 1; transform: translateY(0); }
        }
        .calculator-form h3 {
            margin-top: 0;
            margin-bottom: 20px;
            color: #34495e;
        }
        .form-row {
            display: flex;
            align-items: center;
            gap: 15px;
            margin-bottom: 18px;
        }
        .form-row .input-group {
            flex: 1;
        }
        .form-row label {
            display: block;
            margin-bottom: 8px;
            font-weight: 600;
            color: #555;
            font-size: 0.95rem;
        }
        .form-row input[type="number"] {
            width: 100%;
            padding: 12px;
            border: 1px solid #ccc;
            border-radius: 5px;
            font-size: 1rem;
            transition: border-color 0.3s, box-shadow 0.3s;
        }
        .form-row input[type="number"]:focus {
            border-color: #3498db;
            box-shadow: 0 0 5px rgba(52, 152, 219, 0.5);
            outline: none;
        }
        .calculate-btn {
            width: 100%;
            padding: 15px;
            background: linear-gradient(135deg, #3498db, #2980b9);
            color: #fff;
            border: none;
            border-radius: 5px;
            font-size: 1.2rem;
            font-weight: bold;
            cursor: pointer;
            margin-top: 10px;
            transition: background 0.3s, transform 0.2s;
        }
        .calculate-btn:hover {
            background: linear-gradient(135deg, #2980b9, #2471a3);
            transform: translateY(-2px);
        }
        .result-box {
            margin-top: 25px;
            padding: 20px;
            border-radius: 8px;
            background-color: #eafaf1;
            border-left: 5px solid #2ecc71;
            display: none;
            text-align: center;
        }
        .result-box .result-text {
            font-size: 1.1rem;
            color: #333;
            margin: 0;
        }
        .result-box .result-value {
            font-size: 2.5rem;
            font-weight: 700;
            color: #2c3e50;
            display: block;
            margin-top: 5px;
        }
        .result-box.change-increase { background-color: #eafaf1; border-left-color: #2ecc71; }
        .result-box.change-decrease { background-color: #fbeee6; border-left-color: #e74c3c; }
        
        .progress-bar-container {
            width: 100%;
            height: 25px;
            background-color: #e9ecef;
            border-radius: 12.5px;
            margin-top: 15px;
            overflow: hidden;
        }
        .progress-bar {
            height: 100%;
            width: 0%;
            background: linear-gradient(90deg, #3498db, #5dade2);
            border-radius: 12.5px;
            transition: width 0.5s ease-out;
            text-align: center;
            color: white;
            font-weight: bold;
            line-height: 25px;
            font-size: 0.9rem;
        }
        .error-message {
            color: #e74c3c;
            text-align: center;
            margin-top: 15px;
            font-weight: bold;
            display: none;
        }

        @media (max-width: 768px) {
            .percentage-tool-section { padding: 20px; }
            .percentage-tool-section h1 { font-size: 1.8rem; }
            .form-row { flex-direction: column; align-items: stretch; }
            .calculator-tabs { justify-content: center; }
            .tab-link { flex-grow: 1; text-align: center; }
        }