// Skin · Ingredients · The Brightening Pair — L3 data (COMBINED PAGE: #tranexamic, #azelaic)
// Visual skeleton must match the Oily prototype exactly. Vary copy, never layout.

const OILY = {
  type: "The Brightening Pair",
  parent: { title: "Ingredients", href: "/en/skin/ingredients/" },
  grandparent: { title: "Skin", href: "/en/skin/" },
  totalCount: 109,
  hero: "https://images.unsplash.com/photo-1556228720-195a672e8a03?w=1800&q=80&auto=format&fit=crop",
  heroAlt: "Editorial close-up — translucent brightening serum",
  h1: "The brightening pair.",
  deck: "Tranexamic acid and azelaic acid. Two ingredients doing cosmetic uneven-tone work through different mechanisms — without the instability or irritation overhead of the alternatives.",
  intro: "Tranexamic acid and azelaic acid arrived in mainstream skincare later than vitamin C, with less fanfare, and with better tolerability for most skin tones. Tranexamic acid interferes with the communication pathway that triggers melanin overproduction after inflammation or sun exposure. Azelaic acid slows melanin synthesis directly and doubles as a gentle exfoliant. Neither of them is a substitute for sun protection, which is the primary intervention for all uneven-tone concerns. Both are useful additions to a routine where vitamin C is too irritating or has already done what it can. This page covers both ingredients in detail — what they do, how they compare, and how they can work together.",
  byline: "Edited by Nelly · Beauty & Style Director",
  meta: { count: 109, updated: "Updated 25 April 2026", reading: "Avg. 4 min per piece" },
};

// Ingredients sibling rail — 9 siblings under /en/skin/ingredients/
const TYPE_SIBLINGS = [
  { id: "niacinamide",             title: "Niacinamide",            n: "01", href: "/en/skin/ingredients/niacinamide/" },
  { id: "vitamin-c",               title: "Vitamin C",              n: "02", href: "/en/skin/ingredients/vitamin-c/" },
  { id: "retinoids",               title: "Retinoids",              n: "03", href: "/en/skin/ingredients/retinoids/" },
  { id: "chemical-exfoliants",     title: "Chemical Exfoliants",    n: "04", href: "/en/skin/ingredients/chemical-exfoliants/" },
  { id: "ceramides",               title: "Ceramides",              n: "05", href: "/en/skin/ingredients/ceramides/" },
  { id: "peptides",                title: "Peptides",               n: "06", href: "/en/skin/ingredients/peptides/" },
  { id: "humectants-vs-emollients", title: "Humectants vs Emollients", n: "07", href: "/en/skin/ingredients/humectants-vs-emollients/" },
  { id: "the-brightening-pair",    title: "The Brightening Pair",   n: "08", cur: true, href: "/en/skin/ingredients/the-brightening-pair/" },
  { id: "spf-filters",             title: "SPF Filters",            n: "09", href: "/en/skin/ingredients/spf-filters/" },
];

const QUICK_FACTS = {
  defn: {
    h: "Two ingredients, two mechanisms",
    // Combined page: anchors #tranexamic and #azelaic appear as real h3 ids in the sections
    body: "Tranexamic acid (TXA) and azelaic acid take different paths to a similar outcome — moderating uneven tone caused by post-inflammatory pigmentation, sun exposure, and melanin dysregulation. TXA works by interrupting the signal that tells melanocytes to produce more pigment. Azelaic inhibits tyrosinase, the enzyme that drives melanin synthesis, and has a secondary mild exfoliant function. Both are well-tolerated across skin tones, including darker ones where other actives can worsen the issue they're meant to address.",
  },
  myths: [
    { m: "These ingredients bleach the skin.",
      t: "They moderate melanin production in areas where it's dysregulated. They don't affect normally pigmented skin or change your overall skin tone." },
    { m: "You have to choose between them.",
      t: "Tranexamic and azelaic work through different mechanisms and are compatible. Some people use both. It's a reasonable combination, not an either/or." },
    { m: "They work without sun protection.",
      t: "Sun exposure reactivates the pathways both ingredients are trying to moderate. SPF is not optional in a brightening routine. Everything else is supplemental." },
  ],
};

const BEGINNER_PATH = {
  h: "Start here, if this category is new to you.",
  deck: "Five pieces, in order. The mechanism of each ingredient first, then how to combine them and what to expect.",
  steps: [
    { n: "01", t: "Tranexamic acid — what it does and how",                       time: "4 min", note: "The signalling pathway it interrupts. How TXA differs from other brighteners." },
    { n: "02", t: "Azelaic acid — the ingredient that does two things",            time: "4 min", note: "Tyrosinase inhibition and mild exfoliation. Who it's most useful for." },
    { n: "03", t: "Tranexamic vs azelaic — which to start with",                  time: "3 min", note: "Skin tone, skin type, sensitivity. The decision logic." },
    { n: "04", t: "Using both together — is it worth it",                         time: "3 min", note: "Compatible mechanisms. When combining is the right call." },
    { n: "05", t: "SPF as the primary brightening intervention",                   time: "4 min", note: "Why everything else is secondary to sun protection." },
  ],
};

const TRENDING = [
  { rank: "01", t: "Tranexamic acid vs vitamin C — which to reach for first", time: "4 min", auth: "Nelly", date: "Apr 24", img: "https://images.unsplash.com/photo-1556228720-195a672e8a03?w=1100&q=80&auto=format&fit=crop", reads: "10,447" },
  { rank: "02", t: "Azelaic acid for post-inflammatory pigmentation", time: "4 min", auth: "Iris",  date: "Apr 20", img: "https://images.unsplash.com/photo-1571875257727-256c39da42af?w=1100&q=80&auto=format&fit=crop", reads: "8,903" },
  { rank: "03", t: "Can you use tranexamic acid every day", time: "3 min", auth: "Nelly", date: "Apr 15", img: "https://images.unsplash.com/photo-1598440947619-2c35fc9aa908?w=1100&q=80&auto=format&fit=crop", reads: "7,612" },
  { rank: "04", t: "Azelaic acid concentration — 10% vs 20%", time: "4 min", auth: "Iris",  date: "Apr 10", img: "https://images.unsplash.com/photo-1556228852-80b6e5eeff06?w=1100&q=80&auto=format&fit=crop", reads: "6,304" },
  { rank: "05", t: "The brightening routine for darker skin tones", time: "5 min", auth: "Nelly", date: "Apr 05", img: "https://images.unsplash.com/photo-1512290923902-8a9f81dc236c?w=1100&q=80&auto=format&fit=crop", reads: "5,718" },
];

const FORMAT_GUIDE = {
  h: "Format & cadence, by use case",
  deck: "Tranexamic or azelaic, in which format, at what cadence. Tolerability determines the delivery choice more than skin type.",
  formats: [
    { name: "Tranexamic acid serum (2–5%)", when: "AM or PM, daily, all skin types",     avoid: "Expecting instant results",                     note: "TXA serums at 2–5% are well-tolerated. Daily use is standard. Patient game.", verdict: "★ Daily TXA" },
    { name: "Azelaic acid 10%",             when: "PM, oily to normal skin, alternating", avoid: "Immediately after heavy exfoliation",           note: "10% is OTC in most countries. Gentle enough for daily use on most skin.", verdict: "★ Daily AZ entry" },
    { name: "Azelaic acid 15–20%",          when: "As directed, often alternate nights",  avoid: "Without patch-testing first",                  note: "Prescription-grade or behind-counter in some regions. More potent.", verdict: "Higher strength" },
    { name: "TXA in toner",                 when: "AM, after cleansing, low commitment", avoid: "As sole brightening step",                      note: "Low-concentration daily use. A gentle entry point.", verdict: "Low-intensity" },
    { name: "Azelaic + niacinamide combo",  when: "AM or PM, all skin types",            avoid: "Adding more actives same step",                  note: "AZ and niacinamide are compatible. Combined products or layered.", verdict: "Good pair" },
    { name: "TXA + AZ combined",            when: "PM, experienced brightening routine", avoid: "With strong AHAs same night",                   note: "Both at once is reasonable if each is tolerated. Alternate-night AHAs.", verdict: "Advanced" },
  ],
};

const HOWTOS = [
  { t: "Tranexamic acid vs vitamin C — the decision", time: 4, tech: "Essay", auth: "Nelly", date: "Apr 24", img: "https://images.unsplash.com/photo-1556228720-195a672e8a03?w=900&q=80&auto=format&fit=crop", kick: "Essay", pick: true },
  { t: "Azelaic acid for post-inflammatory pigmentation", time: 4, tech: "Serums", auth: "Iris", date: "Apr 20", img: "https://images.unsplash.com/photo-1571875257727-256c39da42af?w=900&q=80&auto=format&fit=crop", kick: "Ingredients", pick: true },
  { t: "Using tranexamic acid every day — the case for it", time: 3, tech: "Routine", auth: "Nelly", date: "Apr 15", img: "https://images.unsplash.com/photo-1598440947619-2c35fc9aa908?w=900&q=80&auto=format&fit=crop", kick: "Routine", pick: true },
  { t: "Azelaic acid 10% vs 20% — what's worth the difference", time: 4, tech: "Essay", auth: "Iris", date: "Apr 10", img: "https://images.unsplash.com/photo-1556228852-80b6e5eeff06?w=900&q=80&auto=format&fit=crop", kick: "Essay", pick: true },
  { t: "A brightening routine for darker skin tones", time: 5, tech: "Routine", auth: "Nelly", date: "Apr 05", img: "https://images.unsplash.com/photo-1512290923902-8a9f81dc236c?w=900&q=80&auto=format&fit=crop", kick: "Routine", pick: true },
  { t: "How tranexamic acid works — the mechanism", time: 5, tech: "Essay", auth: "Iris", date: "Mar 31", img: "https://images.unsplash.com/photo-1556228720-195a672e8a03?w=900&q=80&auto=format&fit=crop", kick: "Essay", pick: false },
  { t: "Azelaic acid as an exfoliant — the dual function", time: 4, tech: "Essay", auth: "Nelly", date: "Mar 26", img: "https://images.unsplash.com/photo-1570194065650-d99fb4bedf0a?w=900&q=80&auto=format&fit=crop", kick: "Essay", pick: false },
  { t: "TXA and AZ together — is it too much", time: 4, tech: "Layering", auth: "Iris", date: "Mar 21", img: "https://images.unsplash.com/photo-1601049541289-9b1b7bbbfe19?w=900&q=80&auto=format&fit=crop", kick: "Layering", pick: false },
  { t: "Brightening ingredients and SPF — why SPF comes first", time: 3, tech: "Essay", auth: "Nelly", date: "Mar 16", img: "https://images.unsplash.com/photo-1583416750470-965b2707b355?w=900&q=80&auto=format&fit=crop", kick: "Essay", pick: false },
  { t: "Azelaic acid for sensitive skin — the tolerability case", time: 4, tech: "Essay", auth: "Iris", date: "Mar 11", img: "https://images.unsplash.com/photo-1571875257727-256c39da42af?w=900&q=80&auto=format&fit=crop", kick: "Essay", pick: false },
  { t: "Tranexamic acid with niacinamide — a logical stack", time: 3, tech: "Layering", auth: "Nelly", date: "Mar 06", img: "https://images.unsplash.com/photo-1556228852-80b6e5eeff06?w=900&q=80&auto=format&fit=crop", kick: "Layering", pick: false },
  { t: "Azelaic acid and retinoids — same routine or alternating", time: 5, tech: "Layering", auth: "Iris", date: "Mar 01", img: "https://images.unsplash.com/photo-1607006344380-b6775a0824a4?w=900&q=80&auto=format&fit=crop", kick: "Layering", pick: false },
  { t: "What to expect from tranexamic acid at 8 weeks", time: 4, tech: "Routine", auth: "Nelly", date: "Feb 24", img: "https://images.unsplash.com/photo-1598440947619-2c35fc9aa908?w=900&q=80&auto=format&fit=crop", kick: "Routine", pick: false },
  { t: "Azelaic acid in AM vs PM", time: 3, tech: "Routine", auth: "Iris", date: "Feb 19", img: "https://images.unsplash.com/photo-1556228720-195a672e8a03?w=900&q=80&auto=format&fit=crop", kick: "Routine", pick: false },
  { t: "Tranexamic acid toner — the low-intensity version", time: 3, tech: "Format", auth: "Nelly", date: "Feb 14", img: "https://images.unsplash.com/photo-1570194065650-d99fb4bedf0a?w=900&q=80&auto=format&fit=crop", kick: "Format", pick: false },
  { t: "Azelaic acid gel vs cream formulation", time: 3, tech: "Format", auth: "Iris", date: "Feb 09", img: "https://images.unsplash.com/photo-1601049541289-9b1b7bbbfe19?w=900&q=80&auto=format&fit=crop", kick: "Format", pick: false },
  { t: "The brightening pair with vitamin C", time: 4, tech: "Layering", auth: "Nelly", date: "Feb 04", img: "https://images.unsplash.com/photo-1512290923902-8a9f81dc236c?w=900&q=80&auto=format&fit=crop", kick: "Layering", pick: false },
  { t: "Tranexamic acid for sun-related uneven tone", time: 4, tech: "Essay", auth: "Iris", date: "Jan 30", img: "https://images.unsplash.com/photo-1571875257727-256c39da42af?w=900&q=80&auto=format&fit=crop", kick: "Essay", pick: false },
  { t: "Is azelaic acid the same as niacinamide for tone", time: 4, tech: "Essay", auth: "Nelly", date: "Jan 25", img: "https://images.unsplash.com/photo-1556228720-195a672e8a03?w=900&q=80&auto=format&fit=crop", kick: "Essay", pick: false },
  { t: "Starting the brightening pair — the order of introduction", time: 4, tech: "Routine", auth: "Iris", date: "Jan 20", img: "https://images.unsplash.com/photo-1598440947619-2c35fc9aa908?w=900&q=80&auto=format&fit=crop", kick: "Routine", pick: false },
  { t: "Azelaic acid and exfoliants — the frequency math", time: 4, tech: "Layering", auth: "Nelly", date: "Jan 15", img: "https://images.unsplash.com/photo-1583416750470-965b2707b355?w=900&q=80&auto=format&fit=crop", kick: "Layering", pick: false },
  { t: "The 12-week brightening routine — a plan", time: 5, tech: "Routine", auth: "Iris", date: "Jan 10", img: "https://images.unsplash.com/photo-1607006344380-b6775a0824a4?w=900&q=80&auto=format&fit=crop", kick: "Routine", pick: false },
  { t: "Tranexamic acid patch test — is it necessary", time: 3, tech: "Routine", auth: "Nelly", date: "Jan 05", img: "https://images.unsplash.com/photo-1556228852-80b6e5eeff06?w=900&q=80&auto=format&fit=crop", kick: "Routine", pick: false },
  { t: "Azelaic acid in a minimal brightening routine", time: 4, tech: "Routine", auth: "Iris", date: "Dec 31", img: "https://images.unsplash.com/photo-1570194065650-d99fb4bedf0a?w=900&q=80&auto=format&fit=crop", kick: "Routine", pick: false },
];

const TECH_FILTERS = ["All", "Serums", "Layering", "Routine", "Essay", "Format"];

// Crosslinks to 4 adjacent ingredient siblings
const TYPE_CROSSLINKS = [
  { id: "vitamin-c",           title: "Vitamin C",           deck: "The antioxidant brightener. How it compares to TXA.",   count: 138, href: "/en/skin/ingredients/vitamin-c/" },
  { id: "niacinamide",         title: "Niacinamide",          deck: "Compatible with both. A logical layer.",               count: 163, href: "/en/skin/ingredients/niacinamide/" },
  { id: "spf-filters",         title: "SPF Filters",          deck: "The primary brightening intervention.",                count: 120, href: "/en/skin/ingredients/spf-filters/" },
  { id: "chemical-exfoliants", title: "Chemical Exfoliants",  deck: "How AHAs work alongside brightening acids.",          count: 151, href: "/en/skin/ingredients/chemical-exfoliants/" },
];

Object.assign(window, {
  OILY, TYPE_SIBLINGS, QUICK_FACTS, BEGINNER_PATH, TRENDING, FORMAT_GUIDE, HOWTOS, TECH_FILTERS, TYPE_CROSSLINKS,
});