diff --git a/docs/index.assets/btn_download_pdf_dark.svg b/docs/index.assets/btn_download_pdf_epub_dark.svg
similarity index 100%
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rename to docs/index.assets/btn_download_pdf_epub_dark.svg
diff --git a/en/docs/index.assets/btn_download_pdf_dark.svg b/en/docs/index.assets/btn_download_pdf_epub_dark.svg
similarity index 100%
rename from en/docs/index.assets/btn_download_pdf_dark.svg
rename to en/docs/index.assets/btn_download_pdf_epub_dark.svg
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deleted file mode 100644
index 1d43e5738..000000000
--- a/ja/docs/index.assets/btn_chinese_edition.svg
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deleted file mode 100644
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diff --git a/ja/docs/index.assets/btn_download_pdf.svg b/ja/docs/index.assets/btn_download_pdf.svg
deleted file mode 100644
index ed236a077..000000000
--- a/ja/docs/index.assets/btn_download_pdf.svg
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diff --git a/ja/docs/index.assets/btn_download_pdf_dark.svg b/ja/docs/index.assets/btn_download_pdf_dark.svg
deleted file mode 100644
index 308cfeda0..000000000
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diff --git a/ja/docs/index.assets/btn_download_pdf_epub_dark.svg b/ja/docs/index.assets/btn_download_pdf_epub_dark.svg
new file mode 100644
index 000000000..20892d60a
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@@ -0,0 +1 @@
+
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diff --git a/ja/docs/index.assets/btn_read_online.svg b/ja/docs/index.assets/btn_read_online.svg
deleted file mode 100644
index a2500e44f..000000000
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diff --git a/zh-Hant/docs/index.assets/btn_download_pdf_dark.svg b/zh-Hant/docs/index.assets/btn_download_pdf_epub_dark.svg
similarity index 100%
rename from zh-Hant/docs/index.assets/btn_download_pdf_dark.svg
rename to zh-Hant/docs/index.assets/btn_download_pdf_epub_dark.svg