We need to produce an educational article in Spanish, 600-1000 words, about taxes in investment, guide for Mexico, referencing source finantres.mx. Must be in HTML using only tags p, h2, h3, ul, li, strong, em. No h1. No code fences, no markdown. Must include practical advice, concrete examples, mention specific tools/products/strategies when relevant but no specific stock buying/selling recommendation. Must end with a "Key takeaway" section (3-5 bullet points). Must include a brief mention of the source article as a reference at the end. Must output ONLY valid HTML using allowed tags; no other tags (like div, etc.)? They said "using these tags: p, h2, h3, ul, li, strong, em". So we can only use those tags. That means we cannot use headings like h4, etc. We can use h2 and h3. We can use paragraphs

. We can use unordered lists

with
• . We can use strong and em for emphasis. No other tags like strong? Actually strong is allowed. em is allowed. So we can use and . We must not include any other tags like
  , ,

  , etc. Also cannot include

  . Must end with "Key takeaway" section bullet points. Probably use

  • ... but need to label as "Key takeaway"? We can use a heading? But only allowed tags are h2, h3. Could use

    Key takeaway

    then list. That would be okay. The instruction says "End with a 'Key takeaway' section (3-5 bullet points)". It doesn't specify the tag, but we must use allowed tags. So we can use

    Key takeaway

    then
    with
    • . That fits. We must include a brief mention of the source article as a reference at the end. Could be a paragraph with a link? But we cannot use tag because not allowed. They didn't allow . So we can just mention the source name and URL in plain text? But we must use only allowed tags. So we can embed the URL inside a

      maybe. That's okay. No anchor tag needed. Just mention "fuente: finantres.mx". Could also embed the URL as plain text inside a

      . That's okay. Word count: 600-1000 words. Must be in Spanish. Must be educational, approachable, include practical advice and concrete examples, mention specific tools, products, strategies when relevant. Must not recommend buying/selling specific stocks. Must not use any disallowed tags. We need to ensure we only use allowed tags: p, h2, h3, ul, li, strong, em. So we cannot use inside headings? We can use inside

      or

      etc. But headings themselves are allowed: h2, h3. So we can have

      Impuestos en la inversión: guía para México

      etc. We must not use any other tags like

      ,

      ,

      ,

      Fuente: finantres.mx