/* Mobile-first, system font stack: zero webfont requests = faster LCP and no FOUT. */
:root {
  --color-bg: #0f172a;
  --color-surface: #1e293b;
  --color-border: #334155;
  --color-text: #f8fafc;
  --color-text-muted: #cbd5e1;
  --color-accent: #38bdf8;
  --color-accent-hover: #7dd3fc;
  --color-button: #0284c7;
  --color-button-hover: #0369a1;
  --color-focus: #fbbf24;
  --space:1rem;
  --radius: 12px;
  --max-width: 72rem;
  --font: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font);
  font-size: 1.0625rem;
  line-height: 1.6;
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
}

/* Skip link: keyboard/screen-reader UX without affecting visual layout when inactive. */
.skip-link {
  position: absolute;
  left: var(--space);
  top: -100px;
  padding: 0.5rem 1rem;
  background: var(--color-focus);
  color: var(--color-bg);
  font-weight: 700;
  border-radius: 4px;
  z-index: 100;
  transition: top 0.15s ease;
}

.skip-link:focus {
  top: var(--space);
  outline: 3px solid var(--color-text);
  outline-offset: 2px;
}

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

.site-header {
  border-bottom: 1px solid var(--color-border);
  background: var(--color-surface);
}

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

.site-logo {
  color: var(--color-text);
  font-weight: 800;
  font-size: 1.125rem;
  text-decoration: none;
}

.site-logo:hover {
  color: var(--color-accent);
}

.site-logo:focus-visible {
  outline: 3px solid var(--color-focus);
  outline-offset: 3px;
  border-radius: 4px;
}

.site-nav {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem;
}

.site-nav__blog {
  font-weight: 700;
  font-size: 0.9375rem;
  color: var(--color-accent);
  text-decoration: none;
  margin-right: 0.25rem;
}

.site-nav__blog:hover {
  color: var(--color-accent-hover);
  text-decoration: underline;
}

.site-nav__blog:focus-visible {
  outline: 3px solid var(--color-focus);
  outline-offset: 3px;
  border-radius: 4px;
}

.site-footer a {
  color: var(--color-accent);
}

.site-footer a:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 2px;
}

.lang-label {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--color-text-muted);
}

/* Native select: minimal styling, high contrast for WCAG. */
.lang-switcher {
  min-height: 44px;
  padding: 0.375rem 2rem 0.375rem 0.75rem;
  font: inherit;
  color: var(--color-text);
  background: var(--color-bg);
  border: 2px solid var(--color-border);
  border-radius: 8px;
  cursor: pointer;
}

.lang-switcher:focus-visible {
  outline: 3px solid var(--color-focus);
  outline-offset: 2px;
}

main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 2rem 1.25rem 3rem;
}

.hero {
  margin-bottom: 2.5rem;
}

.hero h1 {
  margin: 0 0 0.75rem;
  font-size: clamp(1.75rem, 5vw, 2.5rem);
  line-height: 1.2;
  font-weight: 800;
  letter-spacing: -0.02em;
}

.hero__lede {
  margin: 0 0 1.5rem;
  color: var(--color-text-muted);
  max-width: 42em;
}

.tool-form {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.25rem;
}

.tool-form__label {
  display: block;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.tool-form__row {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.tool-form__input {
  width: 100%;
  min-height: 52px;
  padding: 0.75rem 1rem;
  font: inherit;
  color: var(--color-text);
  background: var(--color-bg);
  border: 2px solid var(--color-border);
  border-radius: 8px;
}

.tool-form__input::placeholder {
  color: #64748b;
}

.tool-form__input:focus-visible {
  border-color: var(--color-accent);
  outline: 3px solid var(--color-focus);
  outline-offset: 2px;
}

/* Primary CTA: 4.5:1+ contrast vs background for text-sized bold text. */
.tool-form__submit {
  min-height: 52px;
   padding: 0.875rem 1.5rem;
  font: inherit;
  font-weight: 800;
  color: #fff;
  background: var(--color-button);
  border: none;
  border-radius: 8px;
  cursor: pointer;
}

.tool-form__submit:hover {
  background: var(--color-button-hover);
}

.tool-form__submit:focus-visible {
  outline: 3px solid var(--color-focus);
  outline-offset: 3px;
}

.tool-form__hint {
  margin: 0.75rem 0 0;
  font-size: 0.875rem;
  color: var(--color-text-muted);
}

.content-grid {
  display: grid;
  gap: 2rem;
}

.content-article h2 {
  margin: 2rem 0 0.75rem;
  font-size: 1.5rem;
  font-weight: 800;
}

.content-article h2:first-child {
  margin-top: 0;
}

.content-article h3 {
  margin: 1.25rem 0 0.5rem;
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--color-accent-hover);
}

.content-article p {
  margin: 0 0 1rem;
  color: var(--color-text-muted);
}

.content-article p:last-child {
  margin-bottom: 0;
}

.feature-list {
  margin: 0;
  padding-left: 1.25rem;
  color: var(--color-text-muted);
}

.feature-list li {
  margin-bottom: 0.5rem;
}

.faq__item {
  margin-bottom: 1.25rem;
  padding-bottom: 1.25rem;
  border-bottom: 1px solid var(--color-border);
}

.faq__item:last-child {
  border-bottom: none;
  margin-bottom: 0;
  padding-bottom: 0;
}

.faq__item h3 {
  margin: 0 0 0.5rem;
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--color-text);
}

.faq__item p {
  margin: 0;
  color: var(--color-text-muted);
}

.content-aside {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.25rem;
  align-self: start;
}

.content-aside h2 {
  margin: 0 0 0.75rem;
  font-size: 1.125rem;
  font-weight: 800;
}

.content-aside__subhead {
  margin-top: 1.5rem;
}

.content-aside p {
  margin: 0;
  font-size: 0.9375rem;
  color: var(--color-text-muted);
}

.content-aside p + p,
.content-aside__note {
  margin-top: 0.75rem;
}

.content-aside__note code {
  font-size: 0.8125rem;
  padding: 0.125rem 0.35rem;
  background: var(--color-bg);
  border-radius: 4px;
  color: var(--color-accent-hover);
  word-break: break-word;
}

/* In-page TOC: internal anchor links for crawlers and users; focus rings match site pattern. */
.aside-toc {
  margin-bottom: 0.25rem;
}

.aside-toc__title {
  margin: 0 0 0.5rem;
  font-size: 1rem;
  font-weight: 800;
}

.aside-toc__list {
  margin: 0;
  padding: 0;
  list-style: none;
  font-size: 0.875rem;
}

.aside-toc__list li {
  margin-bottom: 0.35rem;
}

.aside-toc__list a {
  color: var(--color-accent);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.aside-toc__list a:hover {
  color: var(--color-accent-hover);
}

.aside-toc__list a:focus-visible {
  outline: 3px solid var(--color-focus);
  outline-offset: 2px;
  border-radius: 2px;
}

/* Long-form section dividers: subtle rhythm without heavy decoration. */
.seo-section-divider {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: 2.25rem 0;
}

.content-article code {
  font-size: 0.9em;
  padding: 0.15rem 0.4rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 4px;
  color: var(--color-accent-hover);
  word-break: break-word;
}

/* Definition list glossary: compact SEO reference block. */
.seo-glossary {
  margin: 0;
}

.seo-glossary dt {
  margin-top: 1rem;
  font-weight: 700;
  color: var(--color-text);
}

.seo-glossary dt:first-child {
  margin-top: 0;
}

.seo-glossary dd {
  margin: 0.35rem 0 0;
  color: var(--color-text-muted);
  padding-left: 0;
}

.site-footer {
  border-top: 1px solid var(--color-border);
  padding: 1.5rem 1.25rem;
  text-align: center;
  font-size: 0.875rem;
  color: var(--color-text-muted);
}

.site-footer p {
  margin: 0;
  max-width: var(--max-width);
  margin-inline: auto;
}

/* Tablet+: two-column content; hero button inline where space allows. */
@media (min-width: 640px) {
  .tool-form__row {
    flex-direction: row;
    align-items: stretch;
  }

  .tool-form__input {
    flex: 1;
  }

  .tool-form__submit {
    flex: 0 0 auto;
    min-width: 11rem;
  }
}

@media (min-width: 900px) {
  .content-grid {
    grid-template-columns: 1fr minmax(16rem, 22rem);
    align-items: start;
  }
}

/* --- Blog hub & article pages --- */
.blog-layout {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 2rem 1.25rem 3rem;
}

.blog-layout__intro {
  color: var(--color-text-muted);
  margin: 0 0 2rem;
  max-width: 42em;
}

.blog-page-label {
  font-weight: 600;
  color: var(--color-text-muted);
  font-size: 0.85em;
}

.blog-pager {
  margin: 0 0 1.5rem;
  padding: 1rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
}

.blog-pager__prevnext {
  margin: 0 0 0.5rem;
  font-weight: 600;
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  align-items: center;
}

.blog-pager__nums {
  margin: 0;
  font-size: 0.875rem;
  line-height: 1.8;
  word-break: break-word;
}

.blog-pager__link {
  color: var(--color-accent);
  text-decoration: underline;
  text-underline-offset: 2px;
}

.blog-pager__link:focus-visible {
  outline: 3px solid var(--color-focus);
  outline-offset: 2px;
}

.blog-pager__current {
  font-weight: 800;
  color: var(--color-text);
  padding: 0 0.25rem;
}

.blog-pager__muted {
  color: var(--color-text-muted);
}

.blog-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1rem;
}

@media (min-width: 640px) {
  .blog-list {
    grid-template-columns: repeat(2, 1fr);
  }
}

.blog-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.25rem;
}

.blog-card__link {
  font-weight: 800;
  font-size: 1.0625rem;
  color: var(--color-text);
  text-decoration: none;
}

.blog-card__link:hover {
  color: var(--color-accent);
}

.blog-card__link:focus-visible {
  outline: 3px solid var(--color-focus);
  outline-offset: 2px;
  border-radius: 4px;
}

.blog-card__desc {
  margin: 0.5rem 0 0;
  font-size: 0.9375rem;
  color: var(--color-text-muted);
}

.post-back {
  display: inline-block;
  margin-bottom: 1.5rem;
  font-weight: 600;
  color: var(--color-accent);
  text-decoration: none;
}

.post-back:hover {
  text-decoration: underline;
}

.post-back:focus-visible {
  outline: 3px solid var(--color-focus);
  outline-offset: 2px;
}

.post-meta {
  font-size: 0.875rem;
  color: var(--color-text-muted);
  margin: 0 0 1rem;
}

.post-prose {
  max-width: 42rem;
}

.post-prose h1 {
  margin: 0 0 0.75rem;
  font-size: clamp(1.65rem, 4vw, 2.15rem);
  line-height: 1.2;
  font-weight: 800;
}

.post-prose h2 {
  margin: 2rem 0 0.65rem;
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--color-text);
}

.post-prose h3 {
  margin: 1.25rem 0 0.5rem;
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--color-accent-hover);
}

.post-prose p {
  margin: 0 0 1rem;
  color: var(--color-text-muted);
}

.post-prose ul,
.post-prose ol {
  margin: 0 0 1rem;
  padding-left: 1.35rem;
  color: var(--color-text-muted);
}

.post-prose li {
  margin-bottom: 0.35rem;
}

.post-prose a {
  color: var(--color-accent);
  text-decoration: underline;
  text-underline-offset: 2px;
}

.post-prose a:focus-visible {
  outline: 3px solid var(--color-focus);
  outline-offset: 2px;
}

.post-cross {
  margin: 1.5rem 0;
  padding: 1rem 1.15rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  font-size: 0.9375rem;
  color: var(--color-text-muted);
}

.post-cross a {
  color: var(--color-accent);
  font-weight: 600;
}

.post-related {
  margin-top: 2.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--color-border);
}

.post-related h2 {
  margin: 0 0 0.75rem;
  font-size: 1.125rem;
  font-weight: 800;
}

.post-related ul {
  margin: 0;
  padding-left: 1.25rem;
  color: var(--color-text-muted);
}