Cannot use @import?

use postcss-import plug
code:
{`
@import './style.css';
.title{height: 45px; display: block; text-shadow: 1px 1px 1px #333; line-height: 45px; background: #ff2121; text-align: center; color: white; margin: 10px 0;}
.test{
display: flex;
.test1 {
font-size: 22px;
color: var(--color-blue);
}
}
`}

.babelrc
{
"presets": [
[
"next/babel",
{
"styled-jsx": {
"plugins": [
"styled-jsx-plugin-postcss"
]
}
}
]
]
}

package.json
"postcss": {
"plugins": {
"postcss-cssnext": {
"browsers": [
"last 2 versions",
"> 5%"
]
},
"postcss-nested": {},
"postcss-import": {}
}
}