---
title: "Theming: Customising Headers"
framework: react
version: "36.1.0"
---

# Theming: Customising Headers

Style grid header cells and column groups.

The grid exposes many theme parameters starting `header*` for customising header appearance:

```js
const myTheme = themeQuartz.withParams({
    headerHeight: '30px',
    headerTextColor: 'white',
    headerBackgroundColor: 'black',
    headerCellHoverBackgroundColor: 'rgba(80, 40, 140, 0.66)',
    headerCellMovingBackgroundColor: 'rgb(80, 40, 140)',
});
```

For the full list, see the [Headers section](https://www.ag-grid.com/react-data-grid/theming-api/#reference-headers) of the parameters reference.

When the theme parameters are not enough you can use CSS classes, in particular `ag-header`, `ag-header-cell`, and `ag-header-group-cell`:

```css
.ag-header {
    font-family: cursive;
}
.ag-header-group-cell {
    font-weight: normal;
    font-size: 22px;
}
.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 {
  ColDef,
  ColGroupDef,
  GridApi,
  GridOptions,
  ModuleRegistry,
  Theme,
  enableDevValidations,
  themeQuartz,
} from "ag-grid-community";
import { AllEnterpriseModule } from "ag-grid-enterprise";
import { IOlympicData } from "./interfaces";
import { useFetchJson } from "./useFetchJson";

if (process.env.NODE_ENV !== "production") {
  enableDevValidations();
}

const modules = [AllEnterpriseModule];

const myTheme = themeQuartz.withParams({
  headerHeight: "30px",
  headerTextColor: "white",
  headerBackgroundColor: "black",
  headerCellHoverBackgroundColor: "rgba(80, 40, 140, 0.66)",
  headerCellMovingBackgroundColor: "rgb(80, 40, 140)",
});

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

  const theme = useMemo<Theme | "legacy">(() => {
    return myTheme;
  }, []);
  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}>
          <AgGridReact<IOlympicData>
            rowData={data}
            loading={loading}
            theme={theme}
            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/examples/theming-headers/header-customisation/reactFunctionalTs/)

## Header Column Borders and Resize Handles

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

```js
const myTheme = themeQuartz.withParams({
    headerColumnBorder: { color: 'purple' },
    headerColumnBorderHeight: '80%',

    headerColumnResizeHandleColor: 'orange',
    headerColumnResizeHandleHeight: '25%',
    headerColumnResizeHandleWidth: '5px',
});
```

#### 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 {
  ColDef,
  ColGroupDef,
  GridApi,
  GridOptions,
  ModuleRegistry,
  Theme,
  enableDevValidations,
  themeQuartz,
} from "ag-grid-community";
import { AllEnterpriseModule } from "ag-grid-enterprise";
import { IOlympicData } from "./interfaces";
import { useFetchJson } from "./useFetchJson";

if (process.env.NODE_ENV !== "production") {
  enableDevValidations();
}

const modules = [AllEnterpriseModule];

const myTheme = themeQuartz.withParams({
  headerColumnBorder: { color: "purple" },
  headerColumnBorderHeight: "80%",
  headerColumnResizeHandleColor: "orange",
  headerColumnResizeHandleHeight: "25%",
  headerColumnResizeHandleWidth: "5px",
});

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

  const theme = useMemo<Theme | "legacy">(() => {
    return myTheme;
  }, []);
  const [columnDefs, setColumnDefs] = useState<(ColDef | ColGroupDef)[]>([
    {
      headerName: "Group 1",
      children: [
        { field: "athlete", minWidth: 170, resizable: true },
        { field: "age", resizable: true },
      ],
      resizable: true,
    },
    {
      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,
      resizable: false,
    };
  }, []);

  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}>
          <AgGridReact<IOlympicData>
            rowData={data}
            loading={loading}
            theme={theme}
            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/examples/theming-headers/header-customisation-columns/reactFunctionalTs/)

## Style Header on Filter

Each time a [Column Filter](https://www.ag-grid.com/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 {
  AllCommunityModule,
  ColDef,
  ColGroupDef,
  GridApi,
  GridOptions,
  GridState,
  ModuleRegistry,
  enableDevValidations,
} from "ag-grid-community";
import { IOlympicData } from "./interfaces";
import { useFetchJson } from "./useFetchJson";

if (process.env.NODE_ENV !== "production") {
  enableDevValidations();
}

const modules = [AllCommunityModule];

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 initialState = useMemo<GridState>(() => {
    return {
      filter: {
        filterModel: {
          country: {
            filterType: "text",
            type: "contains",
            filter: "us",
          },
        },
      },
    };
  }, []);

  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}>
          <AgGridReact<IOlympicData>
            rowData={data}
            loading={loading}
            columnDefs={columnDefs}
            defaultColDef={defaultColDef}
            initialState={initialState}
          />
        </div>
      </div>
    </AgGridProvider>
  );
};

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

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

## Styling the First and Last Columns

You can style all first and last column headers (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; /* bluest */
}
.ag-header-cell.ag-column-first {
    background-color: #2244cc44; /* bluer */
}
.ag-floating-filter.ag-column-first {
    background-color: #2244cc22; /* blue */
}

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

#### 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 {
  AllCommunityModule,
  ColDef,
  ColGroupDef,
  GridApi,
  GridOptions,
  ModuleRegistry,
  enableDevValidations,
} from "ag-grid-community";
import { IOlympicData } from "./interfaces";
import { useFetchJson } from "./useFetchJson";

if (process.env.NODE_ENV !== "production") {
  enableDevValidations();
}

const modules = [AllCommunityModule];

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}>
          <AgGridReact<IOlympicData>
            rowData={data}
            loading={loading}
            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/examples/theming-headers/style-header-first-last/reactFunctionalTs/)