@@ -259,6 +259,10 @@ return fault.Wrap(err, fmsg.With("could not calculate file etag"))
 		}
 	}
 
+	if err := content.SeekStart(); err != nil {
+		return fault.Wrap(err, fmsg.With("seeking content start"))
+	}
+
 	err = file.CalculateStyleHash()
 	if err != nil {
 		return fault.Wrap(err, fmsg.With("calculating file hash"))

@@ -2,6 +2,7 @@ package website
 
 import (
 	"encoding/json"
+	"fmt"
 	"net/http"
 	"regexp"
 	"slices"
@@ -77,6 +78,9 @@ }
 	website.counter.Count(r, file.Title)
 	w.Header().Add("ETag", file.Etag)
 	w.Header().Add("Vary", "Accept-Encoding")
+	if file.StyleHash != "" {
+		CSPHeader.StyleSrc = append(CSPHeader.StyleSrc, fmt.Sprintf("'%s'", file.StyleHash))
+	}
 	w.Header().Add("Content-Security-Policy", CSPHeader.String())
 	for k, v := range ExtraHeaders {
 		w.Header().Add(k, v)