---
product: "AG Grid"
title: "Legacy Themes: Customising the Header"
description: "Style grid cells and column groups."
framework: react
version: "36.2.0"
llms: "https://www.ag-grid.com/archive/36.2.0/llms.txt"
---

# Legacy Themes: Customising the Header

Style grid [header](https://www.ag-grid.com/archive/36.2.0/react-data-grid/column-headers/) cells and column groups.

> **Note**
>
> This page describes the grid's legacy theming system that was the default in v32 and before, for the benefit of applications that have not yet migrated to the Theming API. These themes are deprecated and will be removed in a future major version. You may want to visit the [new theming docs](https://www.ag-grid.com/archive/36.2.0/react-data-grid/theming-headers/) or check out the [migration guide](https://www.ag-grid.com/archive/36.2.0/react-data-grid/theming-migration/).

The grid exposes many CSS variables starting `--ag-header-*` for customising header appearance, and when these are not enough you can use CSS classes, in particular `ag-header`, `ag-header-cell`, and `ag-header-group-cell`:

```css
.ag-theme-quartz {
    --ag-header-height: 30px;
    --ag-header-foreground-color: white;
    --ag-header-background-color: black;
    --ag-header-cell-hover-background-color: rgb(80, 40, 140);
    --ag-header-cell-moving-background-color: rgb(80, 40, 140);
}
.ag-theme-quartz .ag-header {
    font-family: cursive;
}
.ag-theme-quartz .ag-header-group-cell {
    font-weight: normal;
    font-size: 22px;
}
.ag-theme-quartz .ag-header-cell {
    font-size: 18px;
}
```

#### Colour Customisation

```tsx
"use client";

import React, {
  useCallback,
  useMemo,
  useRef,
  useState,
  StrictMode,
} from "react";
import { createRoot } from "react-dom/client";
import { AgGridReact, AgGridProvider } from "ag-grid-react";
import "./styles.css";
import "ag-grid-community/styles/ag-grid.css";
import "ag-grid-community/styles/ag-theme-quartz.css";
import {
  ClientSideRowModelModule,
  ColDef,
  ColGroupDef,
  GridApi,
  GridOptions,
  ModuleRegistry,
  NumberEditorModule,
  NumberFilterModule,
  TextEditorModule,
  TextFilterModule,
  Theme,
  enableDevValidations,
} from "ag-grid-community";
import { IOlympicData } from "./interfaces";
import { useFetchJson } from "./useFetchJson";

if (process.env.NODE_ENV !== "production") {
  // Enable extended validations only for development
  enableDevValidations();
}

const modules = [
  NumberEditorModule,
  TextEditorModule,
  TextFilterModule,
  NumberFilterModule,
  ClientSideRowModelModule,
];

const GridExample = () => {
  const containerStyle = useMemo(() => ({ width: "100%", height: "100%" }), []);
  const gridStyle = useMemo(() => ({ height: "100%", width: "100%" }), []);

  const [columnDefs, setColumnDefs] = useState<(ColDef | ColGroupDef)[]>([
    {
      headerName: "Group 1",
      children: [{ field: "athlete", minWidth: 170 }, { field: "age" }],
    },
    {
      headerName: "Group 2",
      children: [
        { field: "country" },
        { field: "year" },
        { field: "date" },
        { field: "sport" },
        { field: "gold" },
        { field: "silver" },
        { field: "bronze" },
        { field: "total" },
      ],
    },
  ]);
  const defaultColDef = useMemo<ColDef>(() => {
    return {
      editable: true,
      filter: true,
    };
  }, []);

  const { data, loading } = useFetchJson<IOlympicData>(
    "https://www.ag-grid.com/example-assets/olympic-winners.json",
  );

  return (
    <AgGridProvider modules={modules}>
      <div style={containerStyle}>
        <div style={gridStyle} className="ag-theme-quartz">
          <AgGridReact<IOlympicData>
            rowData={data}
            loading={loading}
            theme={"legacy"}
            columnDefs={columnDefs}
            defaultColDef={defaultColDef}
          />
        </div>
      </div>
    </AgGridProvider>
  );
};

const root = createRoot(document.getElementById("root")!);
root.render(
  <StrictMode>
    <GridExample />
  </StrictMode>,
);
```

[Live example: Colour Customisation](https://www.ag-grid.com/archive/36.2.0/examples/theming-v32-customisation-headers/header-customisation/reactFunctionalTs/)

## Header Column Separators and Resize Handles

Header Column Separators appear between every column, whereas Resize Handles only appear on resizeable columns (Group 1 in the example below).

```css
.ag-theme-quartz {
    --ag-header-column-separator-display: block;
    --ag-header-column-separator-height: 100%;
    --ag-header-column-separator-width: 2px;
    --ag-header-column-separator-color: purple;

    --ag-header-column-resize-handle-display: block;
    --ag-header-column-resize-handle-height: 25%;
    --ag-header-column-resize-handle-width: 5px;
    --ag-header-column-resize-handle-color: orange;
}
```

#### Column Separators

```tsx
"use client";

import React, {
  useCallback,
  useMemo,
  useRef,
  useState,
  StrictMode,
} from "react";
import { createRoot } from "react-dom/client";
import { AgGridReact, AgGridProvider } from "ag-grid-react";
import "./styles.css";
import "ag-grid-community/styles/ag-grid.css";
import "ag-grid-community/styles/ag-theme-quartz.css";
import {
  ClientSideRowModelModule,
  ColDef,
  ColGroupDef,
  GridApi,
  GridOptions,
  ModuleRegistry,
  NumberEditorModule,
  NumberFilterModule,
  TextEditorModule,
  TextFilterModule,
  Theme,
  enableDevValidations,
} from "ag-grid-community";
import { IOlympicData } from "./interfaces";
import { useFetchJson } from "./useFetchJson";

if (process.env.NODE_ENV !== "production") {
  // Enable extended validations only for development
  enableDevValidations();
}

const modules = [
  NumberEditorModule,
  TextEditorModule,
  TextFilterModule,
  NumberFilterModule,
  ClientSideRowModelModule,
];

const GridExample = () => {
  const containerStyle = useMemo(() => ({ width: "100%", height: "100%" }), []);
  const gridStyle = useMemo(() => ({ height: "100%", width: "100%" }), []);

  const [columnDefs, setColumnDefs] = useState<(ColDef | ColGroupDef)[]>([
    {
      headerName: "Group 1",
      children: [{ field: "athlete", minWidth: 170 }, { field: "age" }],
    },
    {
      headerName: "Group 2",
      children: [
        { field: "country" },
        { field: "year" },
        { field: "date" },
        { field: "sport" },
        { field: "gold" },
        { field: "silver" },
        { field: "bronze" },
        { field: "total" },
      ],
    },
  ]);
  const defaultColDef = useMemo<ColDef>(() => {
    return {
      editable: true,
      filter: true,
    };
  }, []);

  const { data, loading } = useFetchJson<IOlympicData>(
    "https://www.ag-grid.com/example-assets/olympic-winners.json",
  );

  return (
    <AgGridProvider modules={modules}>
      <div style={containerStyle}>
        <div style={gridStyle} className="ag-theme-quartz">
          <AgGridReact<IOlympicData>
            rowData={data}
            loading={loading}
            theme={"legacy"}
            columnDefs={columnDefs}
            defaultColDef={defaultColDef}
          />
        </div>
      </div>
    </AgGridProvider>
  );
};

const root = createRoot(document.getElementById("root")!);
root.render(
  <StrictMode>
    <GridExample />
  </StrictMode>,
);
```

[Live example: Column Separators](https://www.ag-grid.com/archive/36.2.0/examples/theming-v32-customisation-headers/header-customisation-columns/reactFunctionalTs/)

## Style Header on Filter

Each time a [Column Filter](https://www.ag-grid.com/archive/36.2.0/react-data-grid/filtering/) is applied to a column, the CSS class `ag-header-cell-filtered` is added to the header. This can be used for adding style to headers that are filtered.

The example below adds some styling to `ag-header-cell-filtered`, so when you filter a column you will notice the column header change.

#### Style Header

```tsx
"use client";

import React, {
  useCallback,
  useMemo,
  useRef,
  useState,
  StrictMode,
} from "react";
import { createRoot } from "react-dom/client";
import { AgGridReact, AgGridProvider } from "ag-grid-react";
import "./styles.css";
import "ag-grid-community/styles/ag-grid.css";
import "ag-grid-community/styles/ag-theme-quartz.css";
import {
  ClientSideRowModelModule,
  ColDef,
  ColGroupDef,
  GridApi,
  GridOptions,
  ModuleRegistry,
  NumberFilterModule,
  TextFilterModule,
  Theme,
  enableDevValidations,
} from "ag-grid-community";
import { IOlympicData } from "./interfaces";
import { useFetchJson } from "./useFetchJson";

if (process.env.NODE_ENV !== "production") {
  // Enable extended validations only for development
  enableDevValidations();
}

const modules = [
  TextFilterModule,
  NumberFilterModule,
  ClientSideRowModelModule,
];

const GridExample = () => {
  const containerStyle = useMemo(() => ({ width: "100%", height: "100%" }), []);
  const gridStyle = useMemo(() => ({ height: "100%", width: "100%" }), []);

  const [columnDefs, setColumnDefs] = useState<ColDef[]>([
    { field: "athlete" },
    { field: "age", maxWidth: 120 },
    { field: "country" },
    { field: "year", maxWidth: 120 },
    { field: "sport" },
    { field: "gold" },
    { field: "silver" },
    { field: "bronze" },
    { field: "total" },
  ]);
  const defaultColDef = useMemo<ColDef>(() => {
    return {
      flex: 1,
      minWidth: 150,
      filter: true,
    };
  }, []);

  const { data, loading } = useFetchJson<IOlympicData>(
    "https://www.ag-grid.com/example-assets/olympic-winners.json",
  );

  return (
    <AgGridProvider modules={modules}>
      <div style={containerStyle}>
        <div style={gridStyle} className="ag-theme-quartz">
          <AgGridReact<IOlympicData>
            rowData={data}
            loading={loading}
            theme={"legacy"}
            columnDefs={columnDefs}
            defaultColDef={defaultColDef}
          />
        </div>
      </div>
    </AgGridProvider>
  );
};

const root = createRoot(document.getElementById("root")!);
root.render(
  <StrictMode>
    <GridExample />
  </StrictMode>,
);
```

[Live example: Style Header](https://www.ag-grid.com/archive/36.2.0/examples/theming-v32-customisation-headers/style-header-on-filter/reactFunctionalTs/)

## Styling the First and Last Columns

It's possible to style the all first and last column header (Grouped, Non-Grouped and Floating Filters) using CSS by targeting the `.ag-column-first` and `.ag-column-last` selectors as follows:

```css
.ag-header-group-cell.ag-column-first {
    background-color: #2244cc66;
    color: white;
}
.ag-header-cell.ag-column-first {
    background-color: #2244cc44;
    color: white;
}
.ag-floating-filter.ag-column-first {
    background-color: #2244cc22;
}

.ag-header-group-cell.ag-column-last {
    background-color: #33cc3366;
}
.ag-header-cell.ag-column-last {
    background-color: #33cc3344;
}
.ag-floating-filter.ag-column-last {
    background-color: #33cc3322;
}
```

#### Style Header

```tsx
"use client";

import React, {
  useCallback,
  useMemo,
  useRef,
  useState,
  StrictMode,
} from "react";
import { createRoot } from "react-dom/client";
import { AgGridReact, AgGridProvider } from "ag-grid-react";
import "./styles.css";
import "ag-grid-community/styles/ag-grid.css";
import "ag-grid-community/styles/ag-theme-quartz.css";
import {
  ClientSideRowModelModule,
  ColDef,
  ColGroupDef,
  GridApi,
  GridOptions,
  ModuleRegistry,
  NumberFilterModule,
  TextFilterModule,
  Theme,
  enableDevValidations,
} from "ag-grid-community";
import { IOlympicData } from "./interfaces";
import { useFetchJson } from "./useFetchJson";

if (process.env.NODE_ENV !== "production") {
  // Enable extended validations only for development
  enableDevValidations();
}

const modules = [
  TextFilterModule,
  NumberFilterModule,
  ClientSideRowModelModule,
];

const GridExample = () => {
  const containerStyle = useMemo(() => ({ width: "100%", height: "100%" }), []);
  const gridStyle = useMemo(() => ({ height: "100%", width: "100%" }), []);

  const [columnDefs, setColumnDefs] = useState<(ColDef | ColGroupDef)[]>([
    {
      headerName: "Athlete Details",
      children: [
        { field: "athlete" },
        { field: "age", maxWidth: 120 },
        { field: "country" },
      ],
    },
    { field: "year", maxWidth: 100 },
    {
      headerName: "Sport Details",
      children: [
        { field: "total", columnGroupShow: "closed" },
        { field: "gold", columnGroupShow: "open" },
        { field: "silver", columnGroupShow: "open" },
        { field: "bronze", columnGroupShow: "open" },
      ],
    },
  ]);
  const defaultColDef = useMemo<ColDef>(() => {
    return {
      flex: 1,
      minWidth: 150,
      filter: true,
      floatingFilter: true,
    };
  }, []);

  const { data, loading } = useFetchJson<IOlympicData>(
    "https://www.ag-grid.com/example-assets/olympic-winners.json",
  );

  return (
    <AgGridProvider modules={modules}>
      <div style={containerStyle}>
        <div style={gridStyle} className="ag-theme-quartz">
          <AgGridReact<IOlympicData>
            rowData={data}
            loading={loading}
            theme={"legacy"}
            columnDefs={columnDefs}
            defaultColDef={defaultColDef}
          />
        </div>
      </div>
    </AgGridProvider>
  );
};

const root = createRoot(document.getElementById("root")!);
root.render(
  <StrictMode>
    <GridExample />
  </StrictMode>,
);
```

[Live example: Style Header](https://www.ag-grid.com/archive/36.2.0/examples/theming-v32-customisation-headers/style-header-first-last/reactFunctionalTs/)

## Full List of Header Variables

| Property | Type | Required | Default | Description |
| --- | --- | --- | --- | --- |
| `--ag-header-foreground-color` | `CSS color (e.g. `red` or `#fff`)` |  |  |  |
| `--ag-header-background-color` | `CSS color (e.g. `red` or `#fff`)` |  |  |  |
| `--ag-header-cell-hover-background-color` | `CSS color (e.g. `red` or `#fff`)` |  |  |  |
| `--ag-header-cell-moving-background-color` | `CSS color (e.g. `red` or `#fff`)` |  |  |  |
| `--ag-header-height` | `CSS length (e.g. `0`, `4px` or `50%`)` |  |  |  |
| `--ag-header-column-separator-display` | `CSS display value - `block` to show or `none` to hide` |  |  |  |
| `--ag-header-column-separator-height` | `CSS length (e.g. `0`, `4px` or `50%`)` |  |  |  |
| `--ag-header-column-separator-width` | `CSS length (e.g. `0`, `4px` or `50%`)` |  |  |  |
| `--ag-header-column-separator-color` | `CSS color (e.g. `red` or `#fff`)` |  |  |  |
| `--ag-header-column-resize-handle-display` | `CSS display value - `block` to show or `none` to hide` |  |  |  |
| `--ag-header-column-resize-handle-height` | `CSS length (e.g. `0`, `4px` or `50%`)` |  |  |  |
| `--ag-header-column-resize-handle-width` | `CSS length (e.g. `0`, `4px` or `50%`)` |  |  |  |
| `--ag-header-column-resize-handle-color` | `CSS color (e.g. `red` or `#fff`)` |  |  |  |