title: The pseudo class ":first-child" is potentially unsafe when doing server-side rendering. Try changing it to ":first-of-type"
body: <p>I got this error, although there is not a single line in the project with :first-child, why does it appear?
  <a href="https://i.stack.imgur.com/Ia4D2.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/Ia4D2.jpg" alt="enter image description here"></a></p>
  
  <p>......................................................................................................................................................................................................................................................</p>
  
  <pre><code> "dependencies": {
      "@storybook/addon-a11y": "^5.1.9",
      "@trendmicro/react-popover": "^0.4.0",
      "@types/classnames": "^2.2.9",
      "@types/jest": "24.0.13",
      "@types/node": "12.0.2",
      "@types/react": "16.8.18",
      "@types/react-dom": "16.8.4",
      "@types/react-modal": "^3.8.2",
      "@types/storybook__addon-a11y": "^5.0.0",
      "@types/storybook__addon-actions": "^3.4.3",
      "@types/storybook__addon-info": "^4.1.1",
      "@types/storybook__addon-knobs": "^5.0.0",
      "@types/storybook__react": "4.0.1",
      "@types/styled-components": "4.1.15",
      "classnames": "^2.2.6",
      "grommet": "^2.7.2",
      "react": "16.8.6",
      "react-dom": "16.8.6",
      "react-modal": "^3.9.1",
      "react-scripts": "3.0.1",
      "react-toastify": "^5.3.2",
      "styled-components": "^4.2.0",
      "typescript": "^3.5.1"
    },
    "scripts": {
      "start": "react-scripts start",
      "build": "react-scripts build",
      "test": "react-scripts test",
      "eject": "react-scripts eject",
      "storybook": "start-storybook",
      "build-storybook": "build-storybook -c .storybook -o .out",
      "lint": "tslint -c tslint.json src/**/*.{ts,tsx} --fix --format verbose",
      "tslint-check": "tslint-config-prettier-check ./tslint.json",
      "precommit": "lint-staged"
    },
    "lint-staged": {
      "{src,test}/**/*.{ts,tsx}": [
        "prettier --write",
        "git add"
      ]
    },
    "eslintConfig": {
      "extends": "react-app"
    },
    "browserslist": {
      "production": [
        "&gt;0.2%",
        "not dead",
        "not op_mini all"
      ],
      "development": [
        "last 1 chrome version",
        "last 1 firefox version",
        "last 1 safari version"
      ]
    },
    "devDependencies": {
      "@storybook/addon-actions": "5.1.9",
      "@storybook/addon-info": "^5.1.9",
      "@storybook/addon-knobs": "^5.1.9",
      "@storybook/addon-links": "5.1.9",
      "@storybook/addon-storysource": "^5.1.9",
      "@storybook/addons": "5.1.9",
      "@storybook/core-events": "latest",
      "@storybook/react": "5.1.9",
      "@storybook/theming": "latest",
      "husky": "^3.0.0",
      "lint-staged": "^9.1.0",
      "react-docgen-typescript-loader": "3.1.0",
      "react-docgen-typescript-webpack-plugin": "1.1.0",
      "storybook-addon-styled-component-theme": "^1.2.3",
      "ts-loader": "^6.0.4",
      "tslint": "^5.18.0",
      "tslint-config-airbnb": "^5.11.1",
      "tslint-config-prettier": "^1.18.0",
      "tslint-plugin-prettier": "^2.0.1",
      "tslint-react": "^4.0.0"
    }
  </code></pre>