:root {
            --primary-bg: #f4f7f6;
            --container-bg: #ffffff;
            --text-color: #333333;
            --heading-color: #2c3e50;
            --accent-color-1: #00796b; /* Teal for major categories */
            --accent-color-2: #3498db; /* Blue for display categories */
            --accent-color-3: #388e3c; /* Green for sub-categories */
            --search-bg: #eef1f5;
            --hover-bg: #e8f5e9;
            --border-color: #dce1e6;
            --shadow-color: rgba(0, 0, 0, 0.08);
        }

        

        .container {
            border-radius: 12px;

        }

        .search-container {
            margin-bottom: 25px;
            padding: 15px;
            background-color: var(--search-bg);
            border-radius: 8px;
        }

        #calculatorSearch {
            width: 100%;
            padding: 12px 15px;
            border: 1px solid var(--border-color);
            border-radius: 6px;
            font-size: 1em;
            box-sizing: border-box;
        }
        #calculatorSearch:focus {
            outline: none;
            border-color: var(--accent-color-2);
            box-shadow: 0 0 0 2px rgba(52, 152, 219, 0.2);
        }

        .main-page-title {
            text-align: center;
            color: var(--heading-color);
            margin-bottom: 30px;
            font-size: 2.4em;
            font-weight: 600;
        }

        .main-division {
            margin-bottom: 35px;
            padding: 15px;
            border-radius: 8px;
        }
        .main-division:nth-child(odd) { background-color: #fdfefe; }
        .main-division:nth-child(even) { background-color: #f8f9f9; }

        .main-division-title {
            font-size: 1.9em;
            color: var(--heading-color);
            padding-bottom: 12px;
            border-bottom: 3px solid var(--accent-color-1);
            margin-bottom: 25px;
            font-weight: 500;
        }

        .major-category {
            margin-bottom: 25px;
            padding-left: 5px;
        }
        .major-category-title {
            font-size: 1.6em;
            color: var(--accent-color-1);
            margin-bottom: 20px;
            font-weight: 500;
        }

        .display-category {
            margin-bottom: 20px;
            padding-left: 10px;
        }
        .display-category-title {
            font-size: 1.35em;
            color: var(--accent-color-2);
            margin-bottom: 18px;
            padding-bottom: 6px;
            border-bottom: 2px solid var(--accent-color-2);
            display: inline-block;
            font-weight: 500;
        }

        .sub-category {
            margin-bottom: 15px;
            margin-left: 5px;
        }
        .sub-category-header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            cursor: pointer;
            padding: 10px 15px;
            background-color: #e9f7ef; /* Lighter green */
            border-radius: 6px;
            transition: background-color 0.2s ease;
        }
        .sub-category-header:hover {
            background-color: #d4efdf;
        }
        .sub-category-title {
            font-size: 1.1em;
            color: var(--accent-color-3);
            margin: 0;
            font-weight: 500;
        }
        .toggle-btn {
            font-size: 1.4em;
            font-weight: bold;
            color: var(--accent-color-3);
            transition: transform 0.3s ease;
            min-width: 20px; 
            text-align: center;
        }
        .sub-category-header.active .toggle-btn {
            transform: rotate(45deg);
        }

        .calculator-list {
            list-style-type: none;
            padding-left: 20px;
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.35s ease-out, padding-top 0.35s ease-out, padding-bottom 0.35s ease-out;
            margin-top: 0;
            padding-top: 0;
            padding-bottom: 0;
        }
        .sub-category-header.active + .calculator-list {
            max-height: 2000px; /* Increased for potentially very long lists */
            padding-top: 10px;
            padding-bottom: 5px;
        }
        .calculator-list li {
            margin-bottom: 6px;
            font-size: 0.98em;
            display: flex; 
            align-items: center;
        }
        .calculator-icon {
            margin-right: 10px; /* Slightly more space for icon */
            color: var(--accent-color-3);
            font-size: 1.1em; /* Slightly larger icon */
            min-width: 20px; /* Ensure icon alignment */
            text-align: center;
        }
        .calculator-list li a {
            text-decoration: none;
            color: #1D8348; 
            transition: color 0.2s ease, background-color 0.2s ease;
            padding: 5px 8px;
            display: block;
            border-radius: 4px;
            flex-grow: 1;
        }
        .calculator-list li a:hover {
            color: #145A32;
            background-color: var(--hover-bg);
        }

        .hidden-by-search {
            display: none !important;
        }

        @media (max-width: 768px) {
            .container { padding: 15px; }
            .main-page-title { font-size: 2em; }
            .main-division-title { font-size: 1.7em; }
            .major-category-title { font-size: 1.45em; }
            .display-category-title { font-size: 1.25em; }
            .sub-category-title { font-size: 1.05em; }
            .major-category, .display-category, .sub-category { padding-left: 0; margin-left:0; }
        }

        @media (max-width: 480px) {
            .container { padding: 10px; }
            .main-page-title { font-size: 1.7em; }
            .main-division-title { font-size: 1.5em; }
            .major-category-title { font-size: 1.3em; }
            .display-category-title { font-size: 1.15em; }
            .sub-category-title { font-size: 1em; }
            #calculatorSearch { padding: 10px 12px; }
            .sub-category-header { padding: 8px 10px; }
            .calculator-list li a { padding: 6px; }
        }