Solutions
Start from a real-life or work pain point and solve it step by step with the right tool.
Advanced Markdown: Math, Diagrams, Collapsible Blocks, and More
Beyond headings, lists, and tables—how do you write math, draw flowcharts in text, collapse long sections, or add sub/superscripts in Markdown? This guide covers six advanced patterns with source plus real render screenshots, notes on renderer support, and examples you can paste into an online editor.
How Do You Write Markdown? 10 High-Frequency Patterns to Learn by Doing
New to Markdown and stuck on #, *, and backticks? This guide covers only the ten most-used patterns—headings, bold/italic, lists, task lists, links and images, code blocks, quotes, tables, and horizontal rules—each with source plus rendered examples you can paste into an online editor.
How to Play Reversi? Flips, Legal Moves, and Endgame
An illustrated guide—with teaching demo videos—to Reversi (Othello) rules: the opening four discs, how sandwich flips work, why a move must flip at least one disc, multi-direction flips, passing when you have no move, scoring by disc count, plus beginner tips on corners and X-squares.
Need a “Confidential” Watermark on a Contract PDF—What Actually Works?
Before you share contracts, drafts, or course packs, a visible Confidential / Draft watermark helps. This article covers what visible watermarks prevent, when to use text vs a logo, why CJK glyphs go missing, how to choose tiling and page ranges, and what watermarks cannot do.
Chinese in LaTeX Comes Out Blank or Font Not Found? Check Your Engine First
Most CJK LaTeX errors aren't a package problem, they're an engine problem: pdfLaTeX's font model physically cannot hold thousands of Han characters. How the three engines differ, which ctex fontset to pick, and what font not found and ctexart.cls not found actually mean.
LaTeX Showing ?? and Wrong Page Numbers? You Only Compiled Once
The ?? in your PDF and the off-by-one table of contents aren't syntax errors — they mean LaTeX's multi-pass cycle hasn't finished. How .aux and .toc work, how many passes you need, why BibTeX takes four steps, and how to read the log to know you're done.
Why Textbook Solar System Diagrams Don't Stick — and How to Really Learn It
Scale, orbits, and day/night are hard to convey with a flat diagram. This post breaks down three ways textbook illustrations mislead, the intuitions you actually need to grasp the solar system, and how an interactive 3D model makes the abstract concrete.
Want to Learn Drums but Have No Kit? How to Practice Rhythm at Home
A real kit is pricey and loud, and even e-drums cost a small fortune. This post explains what drumming actually trains, which skills you can build with no kit, which you can't, and how to choose by budget.
How to Send Files from Phone to Computer Without a Cable or Messaging App
Phone-to-PC transfer does not have to mean a USB cable or chat app. This article routes by file size, same WiFi or not, and privacy—what cable, messaging, cloud, and LAN direct transfer each fit, and the least hassle pick.
Scanned PDF Too Big to Send? How to Shrink It Down
Scanned contracts and photo PDFs often hit tens of MB—too large for email or WeChat. This article explains why scanned PDFs are so big, what compression actually removes, how small you can go without blurring, and when compression won't help.
Video Too Big to Send? How to Compress It to Fit
WeChat won't send it, email attachments exceed limits, uploads stall—video size exceeds platform caps. This article explains why videos are so large, how small you need to go to send, resolution and compression settings by scenario (WeChat/email/Xiaohongshu/TikTok), and how to balance quality vs. size.
Need to Change One Word on an AI-Generated Page—Re-Prompt or Edit Directly?
ChatGPT/Claude HTML landing pages, reports, and slides are often 90% right—one headline, image, or paragraph off. Re-prompting is slow, burns tokens, and can break what already works. This article explains why you should not go back to the prompt, and how to edit HTML without writing code.
Subtitles Out of Sync? First Identify Which Kind
Downloaded subtitles half a beat slow, or fine at the start but drifting later? Out-of-sync subtitles have three distinct causes and three fixes. This article shows how to tell which you have and fix SRT/VTT/ASS in seconds.
Writing WeChat Articles in Markdown—How to Keep Formatting Intact?
WeChat's editor does not understand Markdown; pasting raw source shows # and *, and styled HTML often loses formatting. This article explains why WeChat layouts break, a stable workflow that keeps .md as source, and how to handle images, code blocks, and formulas.
You Write in Markdown—How Do You Deliver Word or PDF?
Markdown feels great to write, but clients, advisors, and colleagues want Word or PDF. This article compares three conversion paths (paste, pandoc CLI, browser conversion), their pitfalls, and how to handle long docs, images, and fonts.
Someone Sent You a .stl/.obj/.glb File—How Do You Open It?
Got STL, OBJ, GLB, FBX, or USDZ with no professional software installed? This article explains what each format stores, why some lack color or animation, and how to view and convert in the browser without installing anything.
How Do I Open an .html File Someone Sent? The Right Way to Preview Online
You receive an .html file—double-click shows code, broken layout, or missing images. This article explains what .html is, why double-click fails, and concrete ways to preview online, check responsive layout, and open files safely.
How Do I Open a Downloaded .md File? Three Ways to Preview and Share
Double-clicking .md shows code or raw # and *—because it is plain-text source that needs rendering. This article explains what .md is, why it won't open as layout, and concrete ways to preview, convert, and share online.
How Do I Open a Downloaded .tex File? First Understand Why It Won't Open
.tex is LaTeX source, not typeset output—double-clicking does nothing by default. This article explains what .tex is, the cost of each way to view layout, and how to choose by need.
How to Export PDF Pages as Sharp Images
Turn PDF pages into images for WeChat, long-image posts, design assets, or PPT inserts. This article covers why convert, text vs. scanned PDF differences, PNG vs. JPG, resolution settings, and what you lose.
How to Export PPT Slides as Sharp Images
Save each PPT slide as an image for WeChat, mobile viewing, video backgrounds, or Word inserts. This article covers why convert, PNG vs. JPG, resolution, font substitution layout drift, and when conversion fails.
Viewers Can't Find the Action in Your Screen Recording—What to Do?
Full-screen recordings hide where you clicked or edited. This article explains why detail gets lost, how dynamic focus (auto zoom) guides attention, plus speed, silence removal, and background polish—with a tool selection table.
Why Does Word-to-PDF Break Layout and Fonts?
After Word to PDF: wrong line breaks, substituted fonts, widened spaces—usually missing font embedding and different render engines. This article explains layout drift, when change is inevitable, and how to preserve fidelity.
How to Insert Math Formulas in Word, PowerPoint, and WeChat Articles—Write Once, Reuse Everywhere
Word's equation editor is slow for complex formulas, PPT screenshots blur when scaled, and WeChat articles don't support equations. This article explains each platform's limits and a stable workflow: write in LaTeX once, export the right format per platform.
Screen Keeps Dimming While Waiting for AI or Presenting? Temporary Keep-Awake Options
Auto sleep saves power—but sometimes you only need the screen on for a while. This article explains why screens dim, the tradeoffs of system settings vs apps vs browser keep-awake, and the easiest 'use and revert' approach.
LaTeX to PDF Without TeX Live? Know the Limits of Online Conversion First
Installing several GB of TeX just to export one PDF is poor value. This article explains how LaTeX becomes PDF, what online conversion can and cannot do, and how to choose for everyday vs heavy projects.