Problem

When using S3 to serve a static website, CSS files are returned with the content-type of binary/octet-stream. Since the content-type is incorrect, the webpage does not load the CSS file.

Solution

I was using Transmit (4.3.2) to upload my files to S3. By default, Transmit does not set the content-type for CSS files.

To add the correct content-type for specific files with Transmit:

• Open Preferences > Cloud
• Add Extension: css
  • Name: content-type
  • Value: text/css

Now re-upload your CSS files.

Source

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