:root {
  --ink: #151419;
  --muted: #66656d;
  --line: rgba(21, 20, 25, 0.1);
  --surface: #f5f5f7;
  --violet: #6545d7;
  --violet-dark: #4e31bd;
  --violet-soft: #eeeafd;
  --font-display: "Onest", Arial, sans-serif;
  --font-body: "IBM Plex Sans", Arial, sans-serif;
  color-scheme: light;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: #fff; color: var(--ink); font-family: var(--font-body); line-height: 1.65; }
img { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
:focus-visible { outline: 3px solid rgba(101, 69, 215, 0.28); outline-offset: 3px; }
.article-shell { width: min(calc(100% - 32px), 1180px); margin-inline: auto; }
.skip-link { position: fixed; top: 8px; left: 8px; z-index: 20; padding: 10px 14px; border-radius: 10px; background: var(--ink); color: #fff; transform: translateY(-160%); }
.skip-link:focus { transform: translateY(0); }
.article-site-header { position: sticky; top: 0; z-index: 10; border-bottom: 1px solid var(--line); background: rgba(255,255,255,.96); backdrop-filter: blur(14px); }
.article-header-inner { min-height: 82px; display: grid; grid-template-columns: 180px 1fr auto; align-items: center; gap: 30px; }
.article-logo { display: flex; align-items: center; gap: 10px; font-family: var(--font-display); font-size: 22px; }
.article-logo img { width: 44px; height: 44px; }
.article-header-inner nav { display: flex; justify-content: center; gap: 28px; font-size: 14px; font-weight: 650; }
.article-header-inner nav a:hover, .article-header-inner nav a[aria-current="page"] { color: var(--violet); }
.article-contact { color: var(--violet); font-size: 14px; font-weight: 700; }
.articles-hero { padding: 82px 0 54px; }
.articles-hero h1 { max-width: 820px; margin: 0; font: 750 clamp(42px, 6vw, 74px)/1.02 var(--font-display); letter-spacing: -.055em; }
.articles-hero p { max-width: 680px; margin: 24px 0 0; color: var(--muted); font-size: 19px; }
.articles-grid { padding-bottom: 100px; display: grid; grid-template-columns: 1fr 1fr; gap: 24px; }
.articles-grid .article-card:first-child { grid-column: 1 / -1; }
.articles-grid .article-card:first-child > a { display: grid; grid-template-columns: 1.16fr .84fr; height: 100%; }
.articles-grid .article-card:first-child img { height: 100%; }
.article-card { overflow: hidden; border: 1px solid var(--line); border-radius: 20px; background: #f7f7f8; transition: transform 180ms ease, border-color 180ms ease; }
.article-card:hover { transform: translateY(-2px); border-color: #cbc6dc; }
.article-card img { width: 100%; aspect-ratio: 3 / 2; object-fit: cover; }
.article-card-copy { padding: 24px; }
.article-card-meta, .article-meta { display: flex; flex-wrap: wrap; gap: 8px 18px; color: var(--muted); font-size: 13px; }
.article-card h2 { margin: 12px 0 10px; font: 700 clamp(23px, 3vw, 36px)/1.12 var(--font-display); letter-spacing: -.035em; }
.article-card:not(:first-child) h2 { font-size: clamp(21px, 2.2vw, 28px); }
.article-card p { margin: 0; color: var(--muted); }
.article-card-link { width: max-content; margin-top: 22px; display: block; border-bottom: 1px solid currentColor; font-size: 13px; font-weight: 700; }
.article-back { display: inline-flex; margin-top: 34px; color: var(--violet); font-weight: 700; }
.article-hero { padding: 28px 0 44px; }
.article-hero-grid { display: grid; grid-template-columns: minmax(0, .85fr) minmax(420px, 1.15fr); align-items: end; gap: 46px; }
.article-hero h1 { margin: 18px 0; font: 750 clamp(40px, 5.7vw, 72px)/1.02 var(--font-display); letter-spacing: -.052em; }
.article-lead { margin: 0; color: var(--muted); font-size: 19px; }
.article-hero img { width: 100%; aspect-ratio: 3 / 2; object-fit: cover; border-radius: 26px; }
.article-body { width: min(calc(100% - 32px), 800px); margin: 0 auto; padding: 42px 0 110px; font-size: 18px; }
.article-body > p { margin: 0 0 28px; }
.article-body h2 { margin: 58px 0 18px; font: 700 clamp(28px, 4vw, 42px)/1.12 var(--font-display); letter-spacing: -.04em; }
.article-diagram { margin: 42px -90px; display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px; }
.article-diagram > div { min-height: 176px; padding: 22px; border-radius: 20px; background: var(--surface); display: flex; flex-direction: column; justify-content: space-between; }
.article-diagram > div:nth-child(2n) { background: var(--violet-soft); }
.article-diagram b { font: 700 19px/1.2 var(--font-display); }
.article-diagram span { color: var(--muted); font-size: 14px; line-height: 1.45; }
.article-diagram-three { grid-template-columns: repeat(3, 1fr); }
.article-formula { margin: 42px -110px; padding: 26px; border-radius: 24px; background: var(--ink); color: #fff; display: flex; align-items: center; justify-content: center; gap: 14px; }
.article-formula span { padding: 12px 15px; border-radius: 12px; background: rgba(255,255,255,.1); font: 650 16px/1.2 var(--font-display); }
.article-formula i { color: #bfb0ff; font-style: normal; font-size: 24px; }
.article-note { margin-top: 48px; padding: 28px; border-left: 5px solid var(--violet); border-radius: 0 20px 20px 0; background: var(--violet-soft); }
.article-note b { font: 700 20px/1.2 var(--font-display); }
.article-note p { margin: 9px 0 0; }
.article-cta { margin-top: 64px; padding: 30px; border-radius: 24px; background: var(--ink); color: #fff; }
.article-cta h2 { margin: 0 0 12px; color: #fff; }
.article-cta p { margin: 0 0 22px; color: #d6d4dc; }
.article-cta button { min-height: 48px; padding: 0 18px; border: 0; border-radius: 14px; color: #fff; background: var(--violet); font-weight: 700; cursor: pointer; }
.article-cta button:hover { background: var(--violet-dark); }
.article-footer { border-top: 1px solid var(--line); background: var(--surface); color: var(--muted); }
.article-footer .article-shell { min-height: 104px; display: flex; justify-content: space-between; align-items: center; gap: 20px; font-size: 13px; }

.article-request-dialog { width: min(860px, calc(100vw - 32px)); max-width: none; padding: 0; border: 0; border-radius: 24px; background: #fff; color: var(--ink); box-shadow: 0 28px 80px rgba(23,23,26,.24); }
.article-request-dialog::backdrop { background: rgba(23,23,26,.6); backdrop-filter: blur(8px); }
.article-request-layout { display: grid; grid-template-columns: .88fr 1.12fr; }
.article-request-copy { padding: 38px; color: #fff; background: #202025; display: grid; align-content: center; }
.article-request-copy > span { color: #bcaafb; font-size: 12px; font-weight: 700; }
.article-request-copy h2 { margin: 12px 0 14px; font: 700 34px/1.08 var(--font-display); letter-spacing: -.04em; }
.article-request-copy p { margin: 0; color: #c8c7cd; line-height: 1.6; }
.article-request-dialog form { position: relative; padding: 38px; display: grid; gap: 14px; }
.article-request-dialog label { display: grid; gap: 6px; color: #55535c; font-size: 12px; font-weight: 700; }
.article-request-dialog input { min-width: 0; min-height: 50px; padding: 0 14px; border: 1px solid #d8d7dc; border-radius: 12px; background: #fff; color: var(--ink); font: inherit; }
.article-request-dialog input[type="file"] { padding: 12px; }
.article-request-dialog form > button[type="submit"] { min-height: 52px; border: 0; border-radius: 13px; color: #fff; background: var(--violet); font-weight: 700; cursor: pointer; }
.article-request-close { position: absolute; top: 14px; right: 14px; width: 36px; height: 36px; border: 0; border-radius: 50%; background: #efeff1; cursor: pointer; font-size: 24px; line-height: 1; }
.article-request-dialog output { min-height: 20px; color: var(--muted); font-size: 13px; }
.article-request-dialog output.error { color: #a42d2d; }
.article-request-dialog output.success { color: #197149; }

@media (max-width: 900px) {
  .article-header-inner { grid-template-columns: 1fr auto; }
  .article-header-inner nav { display: none; }
  .article-hero-grid { grid-template-columns: 1fr; align-items: start; }
  .article-hero img { order: -1; }
  .article-diagram, .article-diagram-three { margin-inline: 0; grid-template-columns: 1fr 1fr; }
  .article-formula { margin-inline: 0; flex-wrap: wrap; }
}

@media (max-width: 680px) {
  .article-header-inner { min-height: 70px; }
  .article-contact { display: none; }
  .articles-hero { padding: 50px 0 36px; }
  .articles-grid { grid-template-columns: 1fr; padding-bottom: 70px; }
  .articles-grid .article-card:first-child { grid-column: auto; }
  .articles-grid .article-card:first-child > a { display: block; }
  .articles-grid .article-card:first-child img { height: auto; }
  .article-hero { padding-top: 16px; }
  .article-hero-grid { gap: 26px; }
  .article-hero h1 { font-size: 40px; }
  .article-lead { font-size: 17px; }
  .article-body { font-size: 17px; padding-top: 20px; }
  .article-diagram, .article-diagram-three { grid-template-columns: 1fr; }
  .article-diagram > div { min-height: 138px; }
  .article-formula { display: grid; grid-template-columns: 1fr; text-align: center; }
  .article-formula i { line-height: 1; }
  .article-footer .article-shell { padding: 24px 0; display: grid; }
  .article-request-layout { grid-template-columns: 1fr; }
  .article-request-copy, .article-request-dialog form { padding: 26px; }
  .article-request-copy h2 { font-size: 27px; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; transition-duration: .01ms !important; }
}