What causes the 'node-sass' error code 1 during npm install or npm rebuild?

Error code 1 with `node-sass` usually indicates a general compilation failure. Common causes include: missing build tools (like Python, C++ compilers, or Make), incompatible Node.js versions, outdated or conflicting system dependencies, insufficient permissions, or issues with the `node-sass` package itself. It's a broad error, so pinpointing the exact cause requires investigation.