why am I getting error while adding sass support in rollup

Question

I am trying to add sass support using sass plugin to my project which uses rollup but I am getting below error.

[!] RollupError: src/components/RangeInput/RangeInputStyles.scss (1:10): Expected ';', '}' or <eof> (Note that you need plugins to import files that are not JavaScript)
src/components/RangeInput/RangeInputStyles.scss (1:10)
1: $slider-bg: #cfa8f3;
             ^
2: $slider-color: #5d04aa;
3: $slider-height: 10px;
RollupError: Expected ';', '}' or <eof>

Here is my rollup.config.js file.

import resolve from "@rollup/plugin-node-resolve";
import commonjs from "@rollup/plugin-commonjs";
import typescript from "@rollup/plugin-typescript";
import dts from "rollup-plugin-dts";
import terser from "@rollup/plugin-terser";
import peerDepsExternal from "rollup-plugin-peer-deps-external";
import scss from "rollup-plugin-scss";

const packageJson = require("./package.json");

export default [
  {
    input: "src/index.tsx",
    output: [
      {
        file: packageJson.main,
        format: "cjs",
        sourcemap: true,
      },
      {
        file: packageJson.module,
        format: "esm",
        sourcemap: true,
      },
    ],
    plugins: [
      peerDepsExternal(),
      resolve(),
      commonjs(),
      typescript({ tsconfig: "./tsconfig.json" }),
      terser(),
      scss(),
    ],
    external: ["react", "react-dom"],
  },
  {
    input: "src/index.tsx",
    output: [{ file: "dist/types.d.ts", format: "es" }],
    plugins: [dts.default()],
  },
];

And here is my package.json file.

{
  "name": "smart-ui",
  "version": "1.0.0",
  "description": "",
  "main": "dist/cjs/index.js",
  "module": "dist/esm/index.js",
  "types": "dist/index.d.ts",
  "scripts": {
    "rollup": "rollup -c --bundleConfigAsCjs",
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "@rollup/plugin-commonjs": "^25.0.7",
    "@rollup/plugin-node-resolve": "^15.2.3",
    "@rollup/plugin-terser": "^0.4.4",
    "@rollup/plugin-typescript": "^11.1.6",
    "@types/react": "^18.2.69",
    "react": "^18.2.0",
    "rollup": "^4.13.0",
    "rollup-plugin-dts": "^6.1.0",
    "rollup-plugin-peer-deps-external": "^2.2.4",
    "rollup-plugin-postcss": "^4.0.2",
    "rollup-plugin-scss": "^3.0.0",
    "sass": "^1.72.0",
    "tslib": "^2.6.2",
    "typescript": "^5.4.3"
  }
}

What am I missing here and how can I fix it?