:root {
  --bg: #ffffff;
  --bg-soft: #f6f8fb;
  --surface: #ffffff;
  --surface-strong: #eef6f7;
  --text: #172033;
  --muted: #5d6b82;
  --faint: #8190a6;
  --line: #d8e0ea;
  --line-strong: #b9c6d6;
  --indigo: #3147a8;
  --teal: #0e766f;
  --amber: #b46a00;
  --ink: #111827;
  --code-bg: #121826;
  --code-text: #e7edf6;
  --shadow: 0 18px 48px rgba(23, 32, 51, 0.10);
  --radius: 8px;
  --max: 1120px;
  color-scheme: light;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: 17px;
  line-height: 1.65;
}

a {
  color: var(--indigo);
  text-decoration-thickness: 0.08em;
  text-underline-offset: 0.18em;
}

a:hover {
  color: var(--teal);
}

img {
  display: block;
  max-width: 100%;
}

button,
input,
textarea,
select {
  font: inherit;
}

.skip-link {
  position: absolute;
  left: 1rem;
  top: 0.75rem;
  z-index: 100;
  transform: translateY(-180%);
  background: var(--ink);
  color: #ffffff;
  padding: 0.55rem 0.75rem;
  border-radius: var(--radius);
}

.skip-link:focus {
  transform: translateY(0);
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.progress {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 80;
  height: 4px;
  background: transparent;
}

.progress__bar {
  display: block;
  width: 0;
  height: 100%;
  background: linear-gradient(90deg, var(--teal), var(--indigo), var(--amber));
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 70;
  background: rgba(255, 255, 255, 0.92);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(18px);
}

.topbar__inner {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0.75rem 1.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.65rem;
  color: var(--ink);
  text-decoration: none;
  font-weight: 800;
  letter-spacing: 0;
  white-space: nowrap;
}

.brand__mark {
  width: 34px;
  height: 34px;
}

.topbar__links {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  flex-wrap: wrap;
  gap: 0.25rem;
  font-size: 0.92rem;
}

.topbar__links a {
  color: var(--muted);
  text-decoration: none;
  padding: 0.4rem 0.55rem;
  border-radius: var(--radius);
}

.topbar__links a:hover,
.topbar__links a[aria-current="page"] {
  color: var(--ink);
  background: var(--bg-soft);
}

.topbar__links .language-switch {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  min-width: 2.65rem;
  min-height: 2rem;
  padding-inline: 0.45rem;
  font-weight: 800;
}

.flag-icon {
  width: 1.6rem;
  height: auto;
  border-radius: 3px;
  box-shadow: 0 0 0 1px rgba(17, 24, 39, 0.14), 0 1px 2px rgba(17, 24, 39, 0.12);
  flex: 0 0 auto;
}

.language-switch__label {
  font-size: 0.78rem;
  letter-spacing: 0.04em;
}

.hero {
  min-height: calc(100svh - 78px);
  padding: clamp(1.8rem, 4vw, 3rem) 1.25rem clamp(1.6rem, 3vw, 2.35rem);
  display: flex;
  align-items: center;
  border-bottom: 1px solid var(--line);
}

.hero__inner {
  width: 100%;
  max-width: var(--max);
  margin: 0 auto;
  display: grid;
  grid-template-columns: minmax(0, 1.16fr) minmax(300px, 0.84fr);
  gap: clamp(1.6rem, 4.5vw, 4rem);
  align-items: center;
}

.hero h1 {
  margin: 0;
  max-width: 17ch;
  font-size: clamp(2.35rem, 4.2vw, 4rem);
  line-height: 1;
  letter-spacing: 0;
}

.hero__subtitle {
  margin: 0.85rem 0 0;
  color: var(--indigo);
  font-size: clamp(1.18rem, 2.2vw, 1.65rem);
  line-height: 1.12;
  font-weight: 800;
  max-width: 13em;
}

.hero__text {
  margin: 1rem 0 0;
  max-width: 40rem;
  color: var(--muted);
  font-size: 1.04rem;
}

.reading-path {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.55rem;
  margin-top: 1rem;
  color: var(--muted);
  font-size: 0.94rem;
}

.reading-path span {
  font-weight: 800;
  color: var(--ink);
}

.reading-path a {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #ffffff;
  color: var(--indigo);
  padding: 0.25rem 0.45rem;
  text-decoration: none;
}

.reading-path a:hover {
  border-color: var(--teal);
  color: var(--teal);
}

.hero__actions {
  margin-top: 2rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0.7rem 0.95rem;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  color: var(--ink);
  text-decoration: none;
  font-weight: 750;
  background: #ffffff;
}

.button:hover {
  border-color: var(--teal);
  color: var(--teal);
}

.button--primary {
  background: var(--ink);
  color: #ffffff;
  border-color: var(--ink);
}

.button--primary:hover {
  background: var(--teal);
  border-color: var(--teal);
  color: #ffffff;
}

.hero__visual {
  position: relative;
}

.hero__answer-card {
  align-self: center;
  border: 1px solid #b7ded9;
  border-left: 5px solid var(--teal);
  border-radius: var(--radius);
  background: var(--surface-strong);
  box-shadow: var(--shadow);
  padding: clamp(1.1rem, 3vw, 1.65rem);
}

.hero__answer-card strong {
  display: block;
  color: var(--ink);
  font-size: clamp(1.2rem, 2vw, 1.55rem);
}

.hero__answer-card p {
  margin: 0.75rem 0 0;
  color: var(--muted);
  font-size: clamp(1rem, 1.4vw, 1.12rem);
  line-height: 1.6;
}

.section {
  padding: clamp(4rem, 8vw, 6.5rem) 1.25rem;
}

.section--soft {
  background: var(--bg-soft);
  border-block: 1px solid var(--line);
}

.section__inner {
  max-width: var(--max);
  margin: 0 auto;
}

.section__header {
  max-width: 760px;
  margin-bottom: 2rem;
}

.section__number {
  display: block;
  color: var(--teal);
  font-size: 0.82rem;
  font-weight: 850;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 0.35rem;
}

h2 {
  margin: 0;
  font-size: clamp(2rem, 5vw, 3.9rem);
  line-height: 1.02;
  letter-spacing: 0;
}

h3 {
  margin: 0 0 0.65rem;
  font-size: clamp(1.25rem, 3vw, 1.65rem);
  line-height: 1.18;
  letter-spacing: 0;
}

.lead {
  margin: 1rem 0 0;
  color: var(--muted);
  font-size: clamp(1.04rem, 2vw, 1.22rem);
  max-width: 760px;
}

.grid {
  display: grid;
  gap: 1rem;
}

.grid--2 {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.grid--3 {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.card {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
  padding: 1.1rem;
}

.card strong {
  color: var(--ink);
}

.card p {
  margin: 0.45rem 0 0;
  color: var(--muted);
}

.pill-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem;
  padding: 0;
  margin: 1.25rem 0 0;
  list-style: none;
}

.pill-list li {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #ffffff;
  padding: 0.35rem 0.55rem;
  color: var(--muted);
  font-size: 0.9rem;
}

.diagram {
  margin: 1.75rem 0 0;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #ffffff;
  padding: clamp(1rem, 3vw, 1.5rem);
  box-shadow: 0 10px 24px rgba(23, 32, 51, 0.06);
}

.diagram img {
  width: 100%;
  height: auto;
}

.caption {
  margin: 0.85rem 0 0;
  color: var(--muted);
  font-size: 0.92rem;
}

.steps {
  display: grid;
  gap: 1rem;
  counter-reset: step;
  margin-top: 1.5rem;
}

.step {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 0.85rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
  padding: 1rem;
}

.step::before {
  counter-increment: step;
  content: counter(step);
  display: inline-grid;
  place-items: center;
  width: 2rem;
  height: 2rem;
  border-radius: 50%;
  background: var(--indigo);
  color: #ffffff;
  font-weight: 800;
}

.step p {
  margin: 0.35rem 0 0;
  color: var(--muted);
}

.checklist {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.7rem 1rem;
  margin: 1.5rem 0 0;
  padding: 0;
  list-style: none;
}

.checklist li {
  position: relative;
  padding-left: 1.75rem;
  color: var(--muted);
}

.checklist li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.46rem;
  width: 0.75rem;
  height: 0.75rem;
  border-radius: 3px;
  background: var(--teal);
  box-shadow: inset 0 0 0 2px #ffffff;
}

.snippet {
  overflow: hidden;
  border: 1px solid #24304a;
  border-radius: var(--radius);
  background: var(--code-bg);
  margin: 1rem 0;
}

.snippet--compact {
  max-width: 62rem;
}

.snippet--compact pre {
  max-height: 13.5rem;
  overflow: auto;
  padding-block: 0.7rem;
}

.snippet--compact code {
  display: block;
  font-size: 0.82rem;
  line-height: 1.34;
  white-space: pre-wrap;
  overflow-wrap: anywhere;
}

.snippet__top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  min-height: 42px;
  padding: 0.55rem 0.75rem;
  border-bottom: 1px solid #24304a;
  color: #aeb9ca;
  font-size: 0.82rem;
}

.copy-button {
  min-width: 78px;
  border: 1px solid #3a4968;
  border-radius: 6px;
  background: #1b2540;
  color: #f8fafc;
  padding: 0.3rem 0.55rem;
  cursor: pointer;
  font-size: 0.82rem;
}

.copy-button:hover {
  background: #27355b;
}

pre {
  margin: 0;
  overflow-x: auto;
  padding: 0.85rem 1rem;
}

code {
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  font-size: 0.88rem;
}

pre code {
  color: var(--code-text);
  line-height: 1.42;
}

.source-list {
  display: grid;
  gap: 0.85rem;
  margin-top: 1.4rem;
}

.faq-list {
  display: grid;
  gap: 0.85rem;
  margin-top: 1.4rem;
}

.faq-item {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
  padding: 1rem;
}

.faq-item p {
  margin: 0.35rem 0 0;
  color: var(--muted);
}

.source {
  display: grid;
  gap: 0.35rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #ffffff;
  padding: 1rem;
}

.source a {
  font-weight: 800;
}

.source span {
  color: var(--muted);
  font-size: 0.94rem;
}

.callout {
  border: 1px solid #f1d09a;
  border-left: 5px solid var(--amber);
  border-radius: var(--radius);
  background: #fff8ed;
  padding: 1rem;
  margin: 1.4rem 0;
}

.callout p {
  margin: 0;
  color: #5d3d05;
}

.footer {
  padding: 2rem 1.25rem;
  border-top: 1px solid var(--line);
  background: var(--ink);
  color: #dbe4ef;
}

.footer__inner {
  max-width: var(--max);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
}

.footer a {
  color: #ffffff;
}

@media (max-width: 880px) {
  .topbar__inner {
    align-items: flex-start;
    flex-direction: column;
  }

  .hero {
    min-height: auto;
    padding-top: 3rem;
  }

  .hero__inner,
  .grid--2,
  .grid--3,
  .checklist {
    grid-template-columns: 1fr;
  }

  .hero h1 {
    max-width: none;
  }

}

@media (max-width: 560px) {
  body {
    font-size: 16px;
  }

  .topbar__inner,
  .section,
  .hero,
  .footer {
    padding-inline: 1rem;
  }

  .topbar__inner {
    gap: 0.55rem;
    padding-block: 0.6rem;
  }

  .topbar__links {
    width: 100%;
    flex-wrap: nowrap;
    justify-content: flex-start;
    overflow-x: auto;
    padding-bottom: 0.15rem;
    scrollbar-width: thin;
  }

  .topbar__links a {
    flex: 0 0 auto;
    padding-inline: 0.45rem;
  }

  .hero h1 {
    font-size: clamp(2rem, 10vw, 2.85rem);
  }

  .hero__subtitle {
    font-size: clamp(1.08rem, 5vw, 1.34rem);
  }

  .hero__text {
    font-size: 1rem;
  }

  .hero__actions {
    flex-direction: column;
    align-items: stretch;
  }

  .hero__answer-card {
    box-shadow: none;
  }

  .button {
    width: 100%;
  }

  .step {
    grid-template-columns: 1fr;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
  }
}