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When the Hometax e-Tax Invoice Secure Mail (NTS_eTaxInvoice.html) Won't Open
Why the HTML attachment from Korea's National Tax Service shows only a blank page or garbled text, and how to enter the password and read it in the browser with nothing to install. Limits stated plainly.

How to Check a Korean Digital Certificate's Expiry — Open signCert.der
How to see when your Korean joint certificate (formerly 'public certificate') expires before logging in to a bank or Hometax. Open signCert.der from the NPKI folder in the browser to see the validity period and issuer. No password needed.

How to Find & Replace Text Across Word, PowerPoint and Excel — Formatting Intact
Swap names, dates and old brand names across a whole document in one pass. Only the text changes — fonts, tables and layout stay exactly as they were.

How to Unzip and Zip Files — No Software to Install
Open a ZIP you received right in the browser, or bundle several files into one — especially handy on locked-down work PCs where installing software isn't an option.

How to Open HWP Files Without Hancom Office (Mac, Windows, Phone)
How to read Korean HWP documents without installing Hancom Office — a browser viewer with no upload, plus print and save-to-PDF. Rendering limits stated honestly.

Comparing Local LLMs in 2026: Which One Should You Choose Among Llama, Mistral, Phi, and Gemma?
Explore the traits of four major open-weight model families running on laptops and browsers, plus key factors for on-device deployment.