:root {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
  line-height: 1.55;
  --surface-page: #f3f4f6;
  --surface-card: #ffffff;
  --surface-muted: #f8fafc;
  --ink: #0f172a;
  --ink-muted: #475569;
  --ink-faint: #94a3b8;
  --line: #e2e8f0;
  --accent: #4f46e5;
  color-scheme: light;
}

html.dark {
  --surface-page: #0b1220;
  --surface-card: #121a2b;
  --surface-muted: #1a2438;
  --ink: #e8eef9;
  --ink-muted: #9aa8c2;
  --ink-faint: #7b8aa3;
  --line: rgba(148, 163, 184, 0.16);
  --accent: #818cf8;
  color-scheme: dark;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  min-height: 100%;
  background:
    radial-gradient(900px 420px at 8% -8%, color-mix(in srgb, var(--accent) 16%, transparent), transparent 62%),
    var(--surface-page);
  color: var(--ink);
}

main {
  width: min(720px, calc(100% - 32px));
  margin: 32px auto 64px;
}

main.hub {
  width: min(1040px, calc(100% - 32px));
}

.hub-intro {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 24px;
  margin-bottom: 28px;
}

.hub-intro .meta {
  max-width: 28rem;
  margin: 0;
  text-align: right;
}

.feature {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  min-height: 340px;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 24px;
  background: var(--surface-card);
  color: inherit;
  text-decoration: none;
  box-shadow: 0 18px 40px rgba(15, 23, 42, 0.06);
}

.feature:hover {
  text-decoration: none;
  border-color: color-mix(in srgb, var(--accent) 55%, var(--line));
  transform: translateY(-2px);
  box-shadow: 0 22px 48px rgba(15, 23, 42, 0.1);
}

.feature-media {
  display: flex;
  align-items: flex-end;
  padding: 28px 24px 0;
  background: linear-gradient(165deg, #312e81 0%, #0f172a 72%);
}

.feature-media svg,
.feature-media img {
  display: block;
  width: 100%;
  height: auto;
  border-radius: 14px 14px 0 0;
  box-shadow: 0 16px 36px rgba(0, 0, 0, 0.28);
}

.feature-copy {
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 36px 32px;
}

.feature-tag {
  display: inline-flex;
  align-self: flex-start;
  margin: 0 0 12px;
  padding: 4px 10px;
  border-radius: 999px;
  background: color-mix(in srgb, var(--accent) 14%, transparent);
  color: var(--accent);
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.feature-copy h2 {
  margin: 0 0 12px;
  font-size: clamp(1.45rem, 2.4vw, 2rem);
  line-height: 1.2;
}

.feature-copy p {
  margin: 0;
  color: var(--ink-muted);
  font-size: 1.02rem;
}

.feature-read {
  margin-top: 22px;
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--accent);
}

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
  margin-top: 20px;
}

.card {
  display: flex;
  flex-direction: column;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 20px;
  background: var(--surface-card);
  color: inherit;
  text-decoration: none;
}

.card:hover {
  text-decoration: none;
  border-color: var(--accent);
}

.card-media {
  padding: 16px 16px 0;
  background: linear-gradient(165deg, #312e81 0%, #0f172a 72%);
}

.card-media svg,
.card-media img {
  display: block;
  width: 100%;
  height: auto;
  border-radius: 12px 12px 0 0;
}

.card-copy { padding: 20px; }
.card h2 { margin: 0 0 8px; font-size: 1.2rem; }
.card p { margin: 0; color: var(--ink-muted); }

a { color: var(--accent); }
a:hover { text-decoration: underline; }

.top {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 12px 24px;
  background: var(--surface-card);
  border-bottom: 1px solid var(--line);
}

.brand {
  color: inherit;
  text-decoration: none;
  font-weight: 700;
  font-size: 1.05rem;
}
.brand:hover { text-decoration: none; }
.brand span {
  display: block;
  font-size: 11px;
  font-weight: 500;
  color: var(--ink-faint);
}

.nav {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 10px;
}

.lang-select {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  border-radius: 8px;
  border: 1px solid var(--line);
  background: var(--surface-card);
  padding: 4px 8px;
  font-size: 14px;
  color: var(--ink);
}

.lang-select select {
  cursor: pointer;
  background: transparent;
  border: 0;
  outline: none;
  color: var(--ink);
  font-size: 14px;
}

[data-learn-lang] {
  display: none !important;
}

html:not([data-lang]) [data-learn-lang="en"],
html[data-lang="en"] [data-learn-lang="en"],
html[data-lang="es"] [data-learn-lang="es"],
html[data-lang="fr"] [data-learn-lang="fr"],
html[data-lang="de"] [data-learn-lang="de"],
html[data-lang="ru"] [data-learn-lang="ru"] {
  display: revert !important;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 8px;
  padding: 7px 12px;
  font-size: 14px;
  font-weight: 600;
  text-decoration: none;
  border: 1px solid var(--line);
  background: var(--surface-card);
  color: var(--ink);
}
.btn:hover { background: var(--surface-muted); text-decoration: none; }
.btn-primary {
  background: #4f46e5;
  border-color: #4f46e5;
  color: #fff;
}
html.dark .btn-primary {
  background: #6366f1;
  border-color: #6366f1;
}
.btn-primary:hover { filter: brightness(1.05); }
.icon-btn {
  width: 36px;
  padding: 7px;
  color: var(--ink-muted);
}

.kicker {
  margin: 0 0 8px;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--accent);
}

h1 {
  margin: 0 0 8px;
  font-size: 2rem;
  line-height: 1.2;
}

h1 + .article {
  margin-top: 24px;
}

.meta {
  margin: 0 0 28px;
  color: var(--ink-faint);
  font-size: 14px;
}

.article h2 {
  margin: 32px 0 12px;
  font-size: 1.25rem;
}

.article p, .article li {
  color: var(--ink-muted);
  font-size: 1.05rem;
}

.article p { margin: 0 0 1em; }
.article ul, .article ol { margin: 0 0 1.2em; padding-left: 1.2em; }
.article li { margin: 0.35em 0; }
.article strong { color: var(--ink); }

.article-figure {
  margin: 8px 0 1.6em;
  padding: 0;
  border: 1px solid var(--line);
  border-radius: 16px;
  overflow: hidden;
  background: var(--surface-card);
}

.article-figure svg,
.article-figure img {
  display: block;
  width: 100%;
  height: auto;
}

.article-figure figcaption {
  margin: 0;
  padding: 12px 16px 14px;
  border-top: 1px solid var(--line);
  color: var(--ink-muted);
  font-size: 0.92rem;
  line-height: 1.45;
}

.faq {
  margin-top: 40px;
  padding: 20px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--surface-card);
}
.faq h2 { margin-top: 0; }
.faq h3 {
  margin: 18px 0 6px;
  font-size: 1rem;
}

.note {
  margin-top: 28px;
  padding: 16px 18px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--surface-muted);
  color: var(--ink-muted);
  font-size: 0.92rem;
}

.cta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 28px;
}

@media (max-width: 860px) {
  .hub-intro {
    display: block;
  }
  .hub-intro .meta {
    margin-top: 10px;
    text-align: left;
  }
  .feature {
    grid-template-columns: 1fr;
    min-height: 0;
  }
  .feature-copy { padding: 24px 22px 28px; }
}

@media (max-width: 640px) {
  .top { flex-wrap: wrap; padding: 12px 16px; }
  h1 { font-size: 1.6rem; }
  main, main.hub { margin-top: 24px; }
}