:root {
            --primary-color: #1a6fa3;
            --secondary-color: #63b3ed;
            --accent-color: #2b6cb0;
            --light-blue: #ebf8ff;
            --water-color: #4299e1;
            --quality-good: #38a169;
            --quality-fair: #d69e2e;
            --quality-poor: #e53e3e;
            --cation-color: #4299e1;
            --anion-color: #ed8936;
            --text-color: #2d3748;
            --text-muted: #718096;
            --border-color: #e2e8f0;
            --table-header: #f8f9fa;
        }
          .page-header {
            background: linear-gradient(135deg, rgba(99, 179, 237, 0.15) 0%, rgba(26, 111, 163, 0.15) 100%);
            padding: 1.5rem 0;
            margin-bottom: 2rem;
            border-bottom: 1px solid rgba(26, 111, 163, 0.2);
            position: relative;
            overflow: hidden;color: var(--text-color);
        }
        .breadcrumb {
            background-color: transparent;
            padding: 0.5rem 0;
            margin-bottom: 0.5rem;
        }
        .breadcrumb-item a {
            color: var(--text-muted);
            text-decoration: none;
        }
        .breadcrumb-item.active {
            color: var(--text-color);
        }
        .form-control:focus {
            border-color: var(--primary-color);
            box-shadow: 0 0 0 3px rgba(26, 111, 163, 0.15);
        }
        .tds-value-display {
            font-size: 3rem;
            font-weight: 700;
            color: var(--primary-color);
            text-align: center;
            margin: 1rem 0;
        }
        .tds-unit {
            font-size: 1.5rem;
            color: var(--text-muted);
            font-weight: 600;
        }
        .quality-indicator {
            display: flex;
            align-items: center;
            justify-content: space-between;
            background: white;
            padding: 1rem;
            border-radius: 6px;
            margin: 1.5rem 0;
            border: 1px solid var(--border-color);
        }
        .quality-label {
            font-weight: 600;
            font-size: 1.1rem;
        }
        .quality-status {
            padding: 0.5rem 1rem;
            border-radius: 20px;
            font-weight: 600;
            color: white;
        }
        .quality-good {
            background-color: var(--quality-good);
        }
        .quality-fair {
            background-color: var(--quality-fair);
        }
        .quality-poor {
            background-color: var(--quality-poor);
        }
        .water-usage-box {
            background-color: rgba(66, 153, 225, 0.05);
            border-left: 3px solid var(--water-color);
            padding: 1rem;
            border-radius: 0 4px 4px 0;
            margin: 1.5rem 0;
        }
        .water-source-tiles {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
            gap: 1rem;
            margin: 1.5rem 0;
        }
        .water-source-tile {
            background: white;
            border: 1px solid var(--border-color);
            border-radius: 8px;
            padding: 1.5rem;
            text-align: center;
            transition: all 0.3s;
            cursor: pointer;
        }
        .water-source-tile:hover {
            transform: translateY(-5px);
            box-shadow: 0 5px 15px rgba(0,0,0,0.1);
            border-color: var(--primary-color);
        }
        .water-source-tile.active {
            border-color: var(--primary-color);
            background-color: rgba(26, 111, 163, 0.05);
        }
        .water-icon {
            font-size: 2rem;
            color: var(--water-color);
            margin-bottom: 0.5rem;
        }
        .source-tds {
            font-size: 1.25rem;
            font-weight: 600;
            color: var(--primary-color);
            margin: 0.5rem 0;
        }
        @media (max-width: 768px) {
            .tds-value-display {
                font-size: 2.5rem;
            }
            .water-source-tiles {
                grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
            }
            .ion-table-container {
                overflow-x: auto;
            }
        }
        .tds-range-slider {
            margin: 2rem 0;
        }
        .range-labels {
            display: flex;
            justify-content: space-between;
            margin-top: 0.5rem;
            color: var(--text-muted);
            font-size: 0.9rem;
        }
        .conversion-table {
            width: 100%;
            border-collapse: collapse;
            margin: 1.5rem 0;
        }
        .conversion-table th, .conversion-table td {
            padding: 0.75rem;
            text-align: center;
            border: 1px solid var(--border-color);
        }
        .conversion-table th {
            background-color: var(--light-blue);
            font-weight: 600;
        }
        .conversion-table tr:nth-child(even) {
            background-color: rgba(66, 153, 225, 0.05);
        }
        .calc-mode-tabs {
            display: flex;
            border-bottom: 1px solid var(--border-color);
            margin-bottom: 1.5rem;
            flex-wrap: wrap;
        }
        .calc-mode-tab {
            padding: 0.75rem 1.5rem;
            background: none;
            border: none;
            border-bottom: 3px solid transparent;
            font-weight: 600;
            color: var(--text-muted);
            transition: all 0.3s;
            cursor: pointer;
        }
        .calc-mode-tab.active {
            color: var(--primary-color);
            border-bottom-color: var(--primary-color);
            background-color: rgba(26, 111, 163, 0.05);
        }
        .calc-mode-tab:hover:not(.active) {
            color: var(--primary-color);
            background-color: rgba(26, 111, 163, 0.05);
        }
        .calc-mode-content {
            display: none;
        }
        .calc-mode-content.active {
            display: block;
        }
        .quality-meter {
            height: 20px;
            background: linear-gradient(90deg, var(--quality-good) 0%, var(--quality-fair) 50%, var(--quality-poor) 100%);
            border-radius: 10px;
            margin: 1.5rem 0;
            position: relative;
        }
        .quality-indicator-pointer {
            position: absolute;
            top: -5px;
            width: 2px;
            height: 30px;
            background-color: #2d3748;
            transform: translateX(-50%);
        }
        .quality-scale {
            display: flex;
            justify-content: space-between;
            font-size: 0.85rem;
            color: var(--text-muted);
        }
        .ion-table-container {
            margin: 2rem 0;
            border: 1px solid var(--border-color);
            border-radius: 8px;
            overflow: hidden;
        }
        .ion-table-header {
            background-color: var(--table-header);
            padding: 1rem;
            border-bottom: 1px solid var(--border-color);
        }
        .ion-table {
            width: 100%;
            border-collapse: collapse;
        }
        .ion-table th {
            background-color: var(--table-header);
            padding: 0.75rem;
            text-align: center;
            border-bottom: 2px solid var(--border-color);
            font-weight: 600;
            color: var(--text-color);
        }
        .ion-table td {
            padding: 0.75rem;
            text-align: center;
            border-bottom: 1px solid var(--border-color);
        }
        .ion-table tbody tr:hover {
            background-color: rgba(66, 153, 225, 0.05);
        }
        .ion-table input[type="text"],
        .ion-table input[type="number"],
        .ion-table select {
            width: 100%;
            padding: 0.375rem 0.75rem;
            border: 1px solid var(--border-color);
            border-radius: 4px;
            font-size: 0.9rem;
        }
        .ion-label {
            font-weight: 600;
            font-family: 'Cambria', 'Times New Roman', serif;
        }
        .cation-row {
            background-color: rgba(66, 153, 225, 0.05);
        }
        .anion-row {
            background-color: rgba(237, 137, 54, 0.05);
        }
        .ion-balance-results {
            background-color: white;
            border-radius: 8px;
            padding: 1.5rem;
            border: 1px solid var(--border-color);
            margin-top: 1.5rem;
        }
        .balance-indicator {
            display: flex;
            align-items: center;
            justify-content: space-between;
            margin-bottom: 1rem;
        }
        .balance-status {
            padding: 0.5rem 1rem;
            border-radius: 20px;
            font-weight: 600;
        }
        .balance-good {
            background-color: var(--quality-good);
            color: white;
        }
        .balance-warning {
            background-color: var(--quality-fair);
            color: white;
        }
        .balance-error {
            background-color: var(--quality-poor);
            color: white;
        }
        .history-section {
            background-color: white;
            border-radius: 8px;
            padding: 1.5rem;
            border: 1px solid var(--border-color);
            margin-top: 1.5rem;
        }
        .history-item {
            padding: 0.75rem;
            border-bottom: 1px solid var(--border-color);
            display: flex;
            justify-content: space-between;
            align-items: center;
        }
        .history-item:last-child {
            border-bottom: none;
        }
        .history-value {
            font-weight: 600;
            color: var(--primary-color);
        }
        .history-date {
            font-size: 0.85rem;
            color: var(--text-muted);
        }
        .calibration-section {
            background-color: white;
            border-radius: 8px;
            padding: 1.5rem;
            border: 1px solid var(--border-color);
            margin-top: 1.5rem;
        }
        .scenario-presets {
            display: flex;
            flex-wrap: wrap;
            gap: 0.5rem;
            margin: 1rem 0;
        }
        .scenario-preset {
            background-color: rgba(26, 111, 163, 0.1);
            border: 1px solid rgba(26, 111, 163, 0.2);
            border-radius: 4px;
            padding: 0.5rem 0.75rem;
            font-size: 0.9rem;
            color: var(--primary-color);
            cursor: pointer;
            transition: all 0.2s;
        }
        .scenario-preset:hover {
            background-color: rgba(26, 111, 163, 0.2);
            transform: translateY(-2px);
        }