The sx prop

`sx`属性可以用来自定义组件样式

The property is a superset of CSS that packages all the style functions that are exposed in @mui/system. 你可以在它的 prop 上设置任何可用的 css。 You can specify any valid CSS using this prop.

Example

On the example above, you can notice that some of the values are not valid CSS properties. 在上面的例子中，你会发现有些值并不是有效的 css 属性， 这是因为sx的所有 keys 映射的是主题里的属性。 在上面的例子中，你会发现有些值并不是有效的 css 属性， 这是因为sx的所有 keys 映射的是主题里的属性。 In the following sections, you will learn how different sx properties are mapped to specific parts of the theme.

主题相关属性

Borders

The border property can receive only a number as a value. The border property can receive only a number as a value. It creates a solid black border using the number as the width. It creates a solid black border using the number as the width.

<Box sx={{ border: 1 }} />
// 对应生成的border样式: '1px solid black'

borderColor参数接受一个字符串，指向theme.palette

<Box sx={{ borderColor: 'primary.main' }} />
// 默认生成的边框颜色：theme => theme.palette.primary.main

borderRadius 表示主题中theme.shape.borderRadius的倍数(默认为4px)。

<Box sx={{ borderRadius: 2 }} />
// 对应生成的borderRadius为：theme => 2 * theme.shape.borderRadius

Head to the borders page for more details.

Display

displayPrint参数允许你设置display样式，但仅在打印设备上生效。

<Box sx={{ displayPrint: 'none' }} /> // 生成对应样式 '@media print': { display: 'none' }

Head to the display page for more details.

Grid

The grid CSS properties gap, rowGap and columnGap multiply the values they receive by the theme.spacing value (the default for the value is 8px).

<Box sx={{ gap: 2 }} />
// equivalent to gap: theme => theme.spacing(2)

Head to the grid page for more details.

Palette

The color and backgroundColor properties can receive a string, which represents the path in the theme.palette.

<Box sx={{ color: 'primary.main' }} />
// equivalent to color: theme => theme.palette.primary.main

The backgroundColor property is also available trough its alias bgcolor.

<Box sx={{ bgcolor: 'primary.main' }} />
// equivalent to backgroundColor: theme => theme.palette.primary.main

Head to the palette page for more details.

Positions

The zIndex property maps its value to the theme.zIndex value.

<Box sx={{ zIndex: 'tooltip' }} />
// equivalent to zIndex: theme => theme.zIndex.tooltip

Head to the positions page for more details.

Shadows

The boxShadow property maps its value to the theme.shadows value.

<Box sx={{ boxShadow: 1 }} />
// equivalent to boxShadow: theme => theme.shadows[1]

Head to the shadows page for more details.

Sizing

The sizing properties: width, height, minHeight, maxHeight, minWidth and maxWidth are using the following custom transform function for the value:

function transform(value) {
  return value <= 1 ? `${value * 100}%` : value;
}

If the value is between [0, 1], it's converted to percent. Otherwise, it is directly set on the CSS property. Otherwise, it is directly set on the CSS property. Otherwise, it is directly set on the CSS property.

<Box sx={{ width: 1/2 }} /> // equivalent to width: '50%'
<Box sx={{ width: 20 }} /> // equivalent to width: '20px'

Head to the sizing page for more details.

Spacing

The spacing properties: margin, padding and the corresponding longhand properties multiply the values they receive by the theme.spacing value (the default for the value is 8px).

<Box sx={{ margin: 2 }} />
// equivalent to margin: theme => theme.spacing(2)

The following aliases are available for the spacing properties:

Head to the spacing page for more details.

Typography

The fontFamily, fontSize, fontStyle, fontWeight properties map their value to the theme.typography value.

<Box sx={{ fontWeight: 'fontWeightLight' }} />
// equivalent to fontWeight: theme.typography.fontWeightLight

The same can be achieved by omitting the CSS property prefix fontWeight.

<Box sx={{ fontWeight: 'light' }} />
// equivalent to fontWeight: theme.typography.fontWeightLight

There is additional typography prop available, which sets all values defined in the specific theme.typography variant.

<Box sx={{ typography: 'body1' }} />
// equivalent to { ...theme.typography.body1 }

Head to the typography page for more details.

Responsive values

All properties as part of the sx prop also have a support for defining different values for specific breakpoints. For more details on this, take a look at the Responsive values section. For more details on this, take a look at the Responsive values section. For more details on this, take a look at the Responsive values section.

Callback values

Each property in the sx prop can receive a function callback as a value. This is useful when you want to use the theme for calculating some value. This is useful when you want to use the theme for calculating some value. This is useful when you want to use the theme for calculating some value.

<Box sx={{ height: (theme) => theme.spacing(10) }} />

sx can also receive a callback when you need to get theme values that are object:

<Box
  sx={(theme) => ({
    ...theme.typography.body,
    color: theme.palette.primary.main,
  })}
/>

Array values

Array type is useful when you want to partially override some styles in the former index:

<Box
  sx={[
    {
      '&:hover': {
        color: 'red',
        backgroundColor: 'white',
      },
    },
    foo && {
      '&:hover': { backgroundColor: 'grey' },
    },
    bar && {
      '&:hover': { backgroundColor: 'yellow' },
    },
  ]}
/>

When you hover on this element, color: red; backgroundColor: white; is applied.

If foo: true, the color: red; backgroundColor: grey; is applied when hover.

If bar: true, the color: red; backgroundColor: yellow; is applied when hover regardless of foo value, because the higher index of the array has higher specificity.

Note: Each index can be an object or callback

<Box
  sx={[
    { mr: 2, color: 'red' },
    (theme) => ({
      '&:hover': {
        color: theme.palette.primary.main,
      },
    }),
  ]}
/>

Passing sx prop

If you want to receive sx prop from your component and pass it down to MUI's component, we recommend this approach:

TypeScript usage

A frequent source of confusion with the sx prop is TypeScript's type widening, which causes this example not to work as expected:

const style = {
  flexDirection: 'column',
};

export default function App() {
  return <Button sx={style}>Example</Button>;
}
//    Type '{ flexDirection: string; }' is not assignable to type 'SxProps<Theme> | undefined'.
//    Type '{ flexDirection: string; }' is not assignable to type 'CSSSelectorObject<Theme>'.
//      Property 'flexDirection' is incompatible with index signature.
//        Type 'string' is not assignable to type 'SystemStyleObject<Theme>'.
//    Type '{ flexDirection: string; }' is not assignable to type 'CSSSelectorObject<Theme>'.
//      Property 'flexDirection' is incompatible with index signature.
//        Type 'string' is not assignable to type 'SystemStyleObject<Theme>'.
//    Type '{ flexDirection: string; }' is not assignable to type 'CSSSelectorObject<Theme>'.
//      Property 'flexDirection' is incompatible with index signature.
//        Type 'string' is not assignable to type 'SystemStyleObject<Theme>'.

The problem is that the type of the flexDirection prop is inferred as string, which is too wide. The problem is that the type of the flexDirection prop is inferred as string, which is too wide. To fix this, you can cast the object/function passed to the sx prop to const: To fix this, you can cast the object/function passed to the sx prop to const:

const style = {
  flexDirection: 'column',
} as const;

export default function App() {
  return <Button sx={style}>Example</Button>;
}

Alternatively, you can pass the style object directly to the sx prop:

export default function App() {
  return <Button sx={{ flexDirection: 'column' }}>Example</Button>;
}

fill callback gives theme type as any

Since sx can be an array type, there is a conflict in type of Array.fill and CSS's fill property when define value as a callback. As a workaround, you can explicitly define the theme like this: As a workaround, you can explicitly define the theme like this: As a workaround, you can explicitly define the theme like this:

import { Theme } from '@mui/material/styles';

<Box
  sx={{
    fill: (theme: Theme) => theme.palette.primary.main,
  }}
/>;

Let us know or submit a PR if you have a proper way to fix this issue. 🙏 🙏 🙏

Performance

If you are interested in the performance tradeoff, you can find more details here.