:root {
  --xb-bg: #f7f8fc;
  --xb-glass: #ffffffcc;
  --xb-solid: #ffffff;
  --xb-rim: #ffffff80;
  --xb-edge: #dcdef0;
  --xb-ink: #14162b;
  --xb-muted: #4d5370;
  --xb-accent: #4f46e5;
  --xb-deep: #372fa8;
  --xb-warm: #b4532a;
  --xb-r: 18px;
  --xb-r-s: 10px;
  --xb-shadow: 0 1px 2px #14162b12, 0 16px 38px #14162b14;
  --xb-max: 1100px;
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background-color: var(--xb-bg);
  color: var(--xb-ink);
  font: 17px/1.65 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  overflow-wrap: break-word;
}

body::before {
  content: "";
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  z-index: -1;
  background:
    radial-gradient(620px 520px at 10% -8%, #6d5cff2e, #6d5cff00 70%),
    radial-gradient(540px 460px at 94% 4%, #2bb7d92b, #2bb7d900 72%);
}

h1, h2, h3 {
  margin: 0 0 14px;
  line-height: 1.2;
  font-weight: 600;
  letter-spacing: -0.015em;
}

h1 { font-size: clamp(1.9rem, 5vw, 2.7rem); }
h2 { font-size: clamp(1.4rem, 3.2vw, 1.8rem); }
h3 { font-size: 1.12rem; }

p { margin: 0 0 16px; }

a { color: var(--xb-deep); }

a:focus-visible,
button:focus-visible,
summary:focus-visible {
  outline: 2px solid var(--xb-accent);
  outline-offset: 2px;
}

img {
  display: block;
  max-width: 100%;
  height: auto;
  border-radius: var(--xb-r-s);
}

table { border-collapse: collapse; }

code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace;
  font-size: 0.92em;
}

.xb-header {
  position: sticky;
  top: 0;
  z-index: 40;
  background: var(--xb-glass);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--xb-rim);
  box-shadow: 0 1px 2px #14162b0f;
}

.xb-header__in {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
  max-width: var(--xb-max);
  margin: 0 auto;
  padding: 10px 18px;
}

.xb-logo {
  display: inline-flex;
  align-items: baseline;
  gap: 7px;
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--xb-ink);
  text-decoration: none;
  margin-right: auto;
}

.xb-logo span {
  font-size: 0.72rem;
  font-weight: 400;
  color: var(--xb-muted);
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.xb-nav {
  display: flex;
  flex-direction: row;
  align-items: center;
  gap: 20px;
  width: 100%;
  min-width: 0;
  max-width: 100%;
  height: 46px;
  padding-bottom: 2px;
  overflow-x: auto;
  overflow-y: hidden;
  -webkit-overflow-scrolling: touch;
  border-top: 1px solid var(--xb-edge);
}

.xb-nav a {
  display: inline-flex;
  align-items: center;
  flex: 0 0 auto;
  min-height: 44px;
  color: var(--xb-muted);
  font-size: 0.95rem;
  white-space: nowrap;
  text-decoration: none;
}

.xb-nav a:hover { color: var(--xb-deep); }

.xb-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 14px 26px;
  border: 0;
  border-radius: var(--xb-r-s);
  background: var(--xb-accent);
  color: #ffffff;
  font: inherit;
  font-weight: 500;
  line-height: 1.2;
  text-align: center;
  text-decoration: none;
  cursor: pointer;
  transition: background 140ms ease, transform 140ms ease;
}

.xb-btn:hover {
  background: var(--xb-deep);
  transform: translateY(-1px);
}

.xb-btn--ghost {
  background: var(--xb-solid);
  color: var(--xb-deep);
  border: 1px solid var(--xb-edge);
}

.xb-btn--ghost:hover {
  background: #eef0ff;
  color: var(--xb-deep);
}

.xb-btn--small {
  min-height: 44px;
  padding: 10px 18px;
  font-size: 0.92rem;
}

.xb-crumbs {
  max-width: var(--xb-max);
  margin: 0 auto;
  padding: 16px 18px 0;
  font-size: 0.88rem;
  color: var(--xb-muted);
}

.xb-crumbs a { color: var(--xb-deep); }

.xb-hero {
  max-width: var(--xb-max);
  margin: 0 auto;
  padding-top: 40px;
  padding-bottom: 28px;
  padding-left: 18px;
  padding-right: 18px;
}

.xb-hero__card {
  padding: 28px 24px;
  border: 1px solid var(--xb-rim);
  border-radius: var(--xb-r);
  background: var(--xb-glass);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  box-shadow: var(--xb-shadow);
}

.xb-hero__kicker {
  margin: 0 0 10px;
  font-size: 0.84rem;
  color: var(--xb-muted);
}

.xb-hero__lead {
  font-size: 1.06rem;
  color: var(--xb-muted);
  max-width: 62ch;
}

.xb-hero__acts {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 22px;
}

.xb-hero__sign {
  margin: 18px 0 0;
  font-size: 0.86rem;
  color: var(--xb-muted);
}

.xb-panel {
  padding: 22px 20px;
  border: 1px solid var(--xb-rim);
  border-radius: var(--xb-r);
  background: #ffffffd9;
  box-shadow: var(--xb-shadow);
}

.xb-panel h2 { margin-top: 0; }

.xb-panel--tint { background: #f1f2ff; }

.xb-wrap {
  max-width: var(--xb-max);
  margin: 0 auto;
  padding-left: 18px;
  padding-right: 18px;
}

.xb-sec {
  padding-top: 34px;
  padding-bottom: 6px;
}

.xb-lead {
  font-size: 1.04rem;
  max-width: 66ch;
}

.xb-note {
  margin: 10px 0 0;
  font-size: 0.85rem;
  color: var(--xb-muted);
}

.xb-note a { color: var(--xb-deep); }

.xb-bento {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
}

.xb-tile {
  min-width: 0;
  padding: 22px 20px;
  border: 1px solid var(--xb-rim);
  border-radius: var(--xb-r);
  background: #ffffffd9;
  box-shadow: var(--xb-shadow);
}

.xb-tile h2,
.xb-tile h3 { margin-top: 0; }

.xb-tile p:last-child { margin-bottom: 0; }

.xb-tile--accent {
  background: #eceafd;
  border-color: #d5d0f7;
}

.xb-tile--num strong {
  display: block;
  font-size: 2.3rem;
  font-weight: 600;
  line-height: 1.1;
  color: var(--xb-deep);
}

.xb-tile__link {
  display: inline-block;
  margin-top: 6px;
  min-height: 44px;
  padding: 12px 0;
  font-weight: 500;
}

.xb-flow > section { margin-bottom: 8px; }

.xb-zig {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
  align-items: center;
  margin-bottom: 30px;
}

.xb-zig__text,
.xb-zig__art { min-width: 0; }

.xb-zig__text p:last-child { margin-bottom: 0; }

.xb-cards {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
  align-items: start;
}

.xb-card {
  min-width: 0;
  padding: 20px 18px;
  border: 1px solid var(--xb-edge);
  border-radius: var(--xb-r);
  background: var(--xb-solid);
}

.xb-card h3 { margin-top: 0; }

.xb-card p:last-child { margin-bottom: 0; }

.xb-card__tag {
  display: block;
  margin-bottom: 6px;
  font-size: 0.78rem;
  letter-spacing: 0.05em;
  color: var(--xb-muted);
}

.xb-card--lead {
  background: #f0f1ff;
  border-color: #d8daf6;
}

.xb-band {
  padding-top: 34px;
  padding-bottom: 34px;
}

.xb-band--raised {
  background: #eef0fa;
  border-top: 1px solid var(--xb-rim);
  border-bottom: 1px solid var(--xb-rim);
}

.xb-band__in {
  max-width: var(--xb-max);
  margin: 0 auto;
  padding-left: 18px;
  padding-right: 18px;
}

.xb-split {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
  max-width: var(--xb-max);
  margin: 0 auto;
  padding-left: 18px;
  padding-right: 18px;
}

.xb-split__aside {
  min-width: 0;
}

.xb-split__aside p { color: var(--xb-muted); }

.xb-split__main { min-width: 0; }

.xb-split__main > section { margin-bottom: 26px; }

.xb-ladder {
  list-style: none;
  margin: 0;
  padding: 0;
}

.xb-ladder li {
  position: relative;
  padding: 0 0 26px 56px;
}

.xb-ladder li::before {
  content: attr(data-step);
  position: absolute;
  left: 0;
  top: 0;
  width: 38px;
  height: 38px;
  border-radius: 12px;
  background: var(--xb-accent);
  color: #ffffff;
  font-size: 0.95rem;
  line-height: 38px;
  text-align: center;
}

.xb-ladder li::after {
  content: "";
  position: absolute;
  left: 19px;
  top: 44px;
  bottom: 6px;
  width: 1px;
  background: #cdd0ea;
}

.xb-ladder li:last-child::after { display: none; }

.xb-ladder h3 { margin-bottom: 6px; }

.xb-ladder p:last-child { margin-bottom: 0; }

.xb-compare {
  padding: 20px 16px;
  border: 1px solid var(--xb-rim);
  border-radius: var(--xb-r);
  background: #ffffffd9;
  box-shadow: var(--xb-shadow);
}

.xb-compare h2 { margin-top: 0; }

.xb-cover {
  padding-top: 46px;
  padding-bottom: 34px;
}

.xb-cover__in {
  display: grid;
  grid-template-columns: 1fr;
  gap: 22px;
  align-items: end;
  max-width: var(--xb-max);
  margin: 0 auto;
  padding-left: 18px;
  padding-right: 18px;
}

.xb-cover__line {
  font-size: 1.08rem;
  color: var(--xb-muted);
  max-width: 46ch;
}

.xb-body {
  max-width: 720px;
  margin: 0 auto;
  padding-left: 18px;
  padding-right: 18px;
}

.xb-body > section { margin-bottom: 28px; }

.xb-offset {
  display: grid;
  grid-template-columns: 1fr;
  gap: 22px;
  max-width: var(--xb-max);
  margin: 0 auto;
  padding-left: 18px;
  padding-right: 18px;
}

.xb-offset > section {
  min-width: 0;
  margin-bottom: 6px;
}

.xb-toc {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  grid-template-columns: 1fr;
  gap: 2px;
}

.xb-toc a {
  display: inline-block;
  min-height: 44px;
  padding: 12px 0;
  font-size: 0.96rem;
}

.xb-toc span {
  display: inline-block;
  width: 30px;
  color: var(--xb-muted);
}

.xb-scroll {
  min-width: 0;
  overflow-x: auto;
  margin: 6px 0 0;
  border-radius: var(--xb-r-s);
}

.xb-table {
  width: 100%;
  min-width: 520px;
  font-size: 0.95rem;
  background: var(--xb-solid);
}

.xb-table caption {
  padding: 0 0 10px;
  text-align: left;
  font-size: 0.9rem;
  color: var(--xb-muted);
}

.xb-table th,
.xb-table td {
  padding: 10px 12px;
  text-align: left;
  vertical-align: top;
  border-bottom: 1px solid var(--xb-edge);
}

.xb-table thead th {
  background: #eceefb;
  font-weight: 600;
  white-space: nowrap;
}

.xb-table tbody th {
  font-weight: 500;
  color: var(--xb-ink);
}

.xb-table__src {
  margin: 8px 0 0;
  font-size: 0.84rem;
  font-style: italic;
  color: var(--xb-muted);
}

.xb-figure {
  margin: 0 0 18px;
}

.xb-figure img { box-shadow: 0 1px 2px #14162b14, 0 10px 26px #14162b12; }

.xb-figure figcaption {
  margin-top: 8px;
  font-size: 0.85rem;
  color: var(--xb-muted);
}

.xb-figure--s { max-width: 280px; }
.xb-figure--m { max-width: 340px; }
.xb-figure--l { max-width: 390px; }

.xb-gallery {
  display: grid;
  grid-template-columns: 1fr;
  gap: 18px;
}

.xb-gallery .xb-figure { margin-bottom: 0; }

.xb-glossary {
  margin: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 0 34px;
}

.xb-glossary dt {
  font-weight: 600;
  padding-top: 12px;
  border-top: 1px solid var(--xb-edge);
}

.xb-glossary dd {
  margin: 4px 0 12px;
  color: var(--xb-muted);
}

.xb-mistakes {
  margin: 0;
  padding: 0;
  list-style: none;
}

.xb-mistakes li {
  padding: 14px 0;
  border-bottom: 1px solid var(--xb-edge);
}

.xb-mistakes li:last-child { border-bottom: 0; }

.xb-mistakes b {
  display: block;
  font-weight: 600;
}

.xb-mistakes span { color: var(--xb-muted); }

.xb-schema {
  display: block;
  width: 100%;
  max-width: 620px;
  height: auto;
}

.xb-schema text {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 13px;
  fill: #14162b;
}

.xb-timeline {
  margin: 0;
  display: grid;
  grid-template-columns: 1fr;
}

.xb-timeline dt {
  font-weight: 600;
  color: var(--xb-deep);
  padding-top: 12px;
}

.xb-timeline dd {
  margin: 2px 0 12px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--xb-edge);
}

.xb-example {
  margin: 0;
  padding: 16px 14px;
  overflow-x: auto;
  border: 1px solid var(--xb-edge);
  border-left: 3px solid var(--xb-accent);
  border-radius: var(--xb-r-s);
  background: #f4f5ff;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace;
  font-size: 0.86rem;
  line-height: 1.7;
  white-space: pre;
}

.xb-limits {
  margin: 0;
  padding: 0;
  list-style: none;
}

.xb-limits li {
  position: relative;
  padding: 8px 0 8px 26px;
}

.xb-limits li::before {
  content: "";
  position: absolute;
  left: 2px;
  top: 18px;
  width: 12px;
  height: 2px;
  background: var(--xb-warm);
}

.xb-steps {
  margin: 0;
  padding: 0 0 0 22px;
  counter-reset: xb;
}

.xb-steps li {
  padding: 0 0 16px 6px;
}

.xb-steps b { font-weight: 600; }

.xb-myth {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
}

.xb-myth__pair {
  min-width: 0;
  padding: 16px 16px;
  border: 1px solid var(--xb-edge);
  border-radius: var(--xb-r-s);
  background: var(--xb-solid);
}

.xb-myth__pair p { margin: 0; }

.xb-myth__said {
  color: var(--xb-muted);
  font-style: italic;
  margin-bottom: 8px !important;
}

.xb-calc {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  grid-template-columns: 1fr;
  gap: 10px;
}

.xb-calc li {
  display: flex;
  justify-content: space-between;
  gap: 14px;
  padding: 12px 14px;
  border: 1px solid var(--xb-edge);
  border-radius: var(--xb-r-s);
  background: var(--xb-solid);
}

.xb-calc b {
  font-weight: 600;
  color: var(--xb-deep);
  white-space: nowrap;
}

.xb-faq details {
  border-bottom: 1px solid var(--xb-edge);
}

.xb-faq summary {
  padding: 15px 0;
  font-weight: 500;
  cursor: pointer;
  min-height: 44px;
}

.xb-faq p {
  margin: 0 0 15px;
  color: var(--xb-muted);
  max-width: 66ch;
}

.xb-cta {
  max-width: var(--xb-max);
  margin: 34px auto 40px;
  padding: 30px 24px;
  border: 1px solid var(--xb-rim);
  border-radius: var(--xb-r);
  background: var(--xb-glass);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  box-shadow: var(--xb-shadow);
}

.xb-cta h2 { margin-top: 0; }

.xb-cta p { color: var(--xb-muted); }

.xb-cta__wrap {
  padding-left: 18px;
  padding-right: 18px;
}

.xb-footer {
  border-top: 1px solid var(--xb-rim);
  background: #eceefa;
}

.xb-footer__in {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
  max-width: var(--xb-max);
  margin: 0 auto;
  padding: 30px 18px 36px;
  font-size: 0.93rem;
}

.xb-footer h2 {
  font-size: 0.82rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--xb-muted);
  margin-bottom: 8px;
}

.xb-footer p { color: var(--xb-muted); }

.xb-footer ul {
  margin: 0;
  padding: 0;
  list-style: none;
}

.xb-footer li a {
  display: inline-block;
  min-height: 44px;
  padding: 12px 0;
}

.xb-footer__rev {
  border-top: 1px solid var(--xb-edge);
  padding-top: 14px;
  font-size: 0.85rem;
  color: var(--xb-muted);
}

.xb-cookie {
  position: fixed;
  left: 12px;
  right: 12px;
  bottom: 12px;
  z-index: 60;
  display: none;
  padding: 18px 18px;
  border: 1px solid var(--xb-rim);
  border-radius: var(--xb-r);
  background: #ffffffef;
  box-shadow: 0 2px 6px #14162b1f, 0 18px 44px #14162b24;
}

.xb-cookie.is-open { display: block; }

.xb-cookie p {
  margin: 0 0 14px;
  font-size: 0.9rem;
  color: var(--xb-muted);
}

.xb-cookie__acts {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.xb-cookie__acts .xb-btn { flex: 1 1 auto; }

.xb-legal h2 { margin-top: 26px; }

.xb-legal p,
.xb-legal li { color: #2a2e46; }

.xb-legal ul { padding-left: 20px; }

.xb-legal li { margin-bottom: 8px; }

.xb-reveal.is-armed {
  opacity: 0;
  transform: translateY(10px);
  transition: opacity 320ms ease, transform 320ms ease;
}

.xb-reveal.is-armed.is-in {
  opacity: 1;
  transform: none;
}

@media (min-width: 560px) {
  .xb-cookie__acts .xb-btn { flex: 0 0 auto; }
  .xb-figure--s { max-width: 300px; }
  .xb-myth { grid-template-columns: 1fr 1fr; }
}

@media (min-width: 700px) {
  .xb-hero { padding-top: 54px; }
  .xb-hero__card { padding: 38px 34px; }
  .xb-panel { padding: 26px 26px; }
  .xb-tile { padding: 26px 24px; }
  .xb-cards { grid-template-columns: 1fr 1fr; }
  .xb-gallery { grid-template-columns: 1fr 1fr; }
  .xb-cta { padding: 40px 38px; }
  .xb-toc { grid-template-columns: 1fr 1fr; }
  .xb-calc { grid-template-columns: 1fr 1fr; }
}

@media (min-width: 760px) {
  .xb-glossary { grid-template-columns: 1fr 1fr; }
}

@media (min-width: 880px) {
  .xb-bento { grid-template-columns: repeat(6, 1fr); }
  .xb-tile--wide { grid-column: span 6; }
  .xb-tile--two { grid-column: span 4; }
  .xb-tile--one { grid-column: span 2; }
  .xb-tile--half { grid-column: span 3; }
  .xb-zig { grid-template-columns: 1fr 380px; gap: 34px; }
  .xb-zig--flip .xb-zig__text { order: 2; }
  .xb-zig--flip .xb-zig__art { order: 1; }
  .xb-split { grid-template-columns: 300px 1fr; gap: 40px; }
  .xb-split__aside { position: sticky; top: 78px; align-self: start; }
  .xb-cover__in { grid-template-columns: 1fr 400px; }
  .xb-cards--three { grid-template-columns: repeat(3, 1fr); }
  .xb-footer__in { grid-template-columns: 1.4fr 1fr 1fr; }
  .xb-offset { grid-template-columns: repeat(12, 1fr); }
  .xb-offset__a { grid-column: 1 / 9; }
  .xb-offset__b { grid-column: 4 / 13; }
  .xb-offset__c { grid-column: 2 / 10; }
  .xb-offset__d { grid-column: 5 / 13; }
  .xb-offset__e { grid-column: 1 / 11; }
  .xb-offset__f { grid-column: 3 / 13; }
  .xb-compare { padding: 28px 26px; }
}

@media (min-width: 940px) {
  .xb-nav {
    gap: 22px;
    width: auto;
    height: auto;
    padding-bottom: 0;
    margin-right: 18px;
    overflow-x: visible;
    border-top: 0;
  }
}

@media (prefers-reduced-motion: reduce) {
  .xb-reveal.is-armed {
    opacity: 1;
    transform: none;
    transition: none;
  }
  .xb-btn:hover { transform: none; }
  * { transition-duration: 1ms !important; }
}