:root {
  --color-bg: #fcfdff;
  --color-surface: #fff;
  --color-text: #161a20;
  --color-muted: #5f6772;
  --color-border: #d7dee8;
  --color-accent: #1d4f91;
  --color-link-hover: #123362;
  --color-hover: #f4f8fd;
  --container-max: 980px;
  --font-body: Arial, Helvetica, sans-serif;
  --font-heading: Georgia, "Times New Roman", serif;
}

[data-theme="dark"] {
  --color-bg: #000;
  --color-surface: #111;
  --color-text: #fff;
  --color-muted: #b8b8b8;
  --color-border: #454545;
  --color-accent: #8eb7e8;
  --color-link-hover: #b8d7ff;
  --color-hover: #1c1c1c;
}

[data-theme="dark"] .article pre {
  background: #171717;
  color: #fff;
}

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

html {
  scroll-behavior: auto;
}

body {
  margin: 0;
  min-height: 100vh;
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.6;
}

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

a:hover,
a:focus {
  color: var(--color-link-hover);
}

.skip-link {
  position: absolute;
  top: 8px;
  left: 8px;
  z-index: 10;
  padding: 4px 8px;
  background: #fff;
  color: #000;
  transform: translateY(-150%);
}

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

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: var(--container-max);
  min-height: 68px;
  margin: 0 auto;
  padding: 12px 24px;
  border-bottom: 1px solid var(--color-border);
  background: var(--color-bg);
}

.site-nav ul {
  display: flex;
  gap: 22px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.site-nav a {
  color: var(--color-text);
  font-size: 0.8rem;
  font-weight: bold;
  letter-spacing: 0.04em;
  text-decoration: none;
}

.site-nav a:hover,
.site-nav a:focus {
  color: var(--color-accent);
  text-decoration: underline;
}

.theme-toggle {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 5px 9px;
  border: 1px solid var(--color-border);
  border-radius: 2px;
  background: transparent;
  color: var(--color-text);
  cursor: pointer;
  font: inherit;
  font-size: 0.75rem;
}

.theme-toggle:hover,
.theme-toggle:focus {
  border-color: var(--color-accent);
  color: var(--color-accent);
}

.hero,
.section,
.blog-article {
  max-width: var(--container-max);
  margin: 0 auto;
  padding-right: 24px;
  padding-left: 24px;
}

.hero {
  min-height: 500px;
  padding-top: 110px;
  padding-bottom: 100px;
  border-bottom: 1px solid var(--color-border);
}

.hero__content h1 {
  max-width: 680px;
  margin: 0 0 20px;
  color: var(--color-text);
  font-family: var(--font-heading);
  font-size: clamp(3.2rem, 9vw, 6.5rem);
  font-weight: normal;
  line-height: 0.98;
}

.hero__sub {
  max-width: 470px;
  margin: 0;
  color: var(--color-muted);
  font-size: 1.1rem;
}

.section {
  padding-top: 72px;
  padding-bottom: 72px;
  border-bottom: 1px solid var(--color-border);
}

.grid-container {
  display: grid;
  grid-template-columns: 150px 1fr;
  gap: 44px;
  max-width: 820px;
  margin: 0 auto;
}

.label {
  margin: 0 0 16px;
  color: var(--color-muted);
  font-size: 0.75rem;
  font-weight: bold;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.content h2,
.contact-panel h2,
.article h1,
.article h2,
.article h3 {
  color: var(--color-text);
  font-family: var(--font-heading);
  font-weight: normal;
}

.content h2 {
  margin: 0 0 20px;
  font-size: 2.4rem;
  line-height: 1.15;
}

.content p {
  max-width: 650px;
  margin: 0 0 20px;
  color: var(--color-text);
}

.blog-list-minimal {
  border-top: 1px solid var(--color-border);
}

.blog-item {
  display: flex;
  gap: 24px;
  align-items: baseline;
  padding: 16px 0;
  border-bottom: 1px solid var(--color-border);
  color: var(--color-text);
  text-decoration: none;
}

.blog-item:hover,
.blog-item:focus {
  padding-left: 8px;
  background: var(--color-hover);
  color: var(--color-accent);
}

.blog-item .date {
  min-width: 58px;
  color: var(--color-muted);
  font-size: 0.8rem;
  text-transform: uppercase;
}

.blog-item .title {
  font-weight: bold;
}

.btn {
  display: inline-block;
  padding: 8px 16px;
  border: 1px solid var(--color-accent);
  border-radius: 2px;
  background: transparent;
  color: var(--color-accent);
  font-size: 0.85rem;
  font-weight: bold;
  text-decoration: none;
}

.btn:hover,
.btn:focus {
  background: var(--color-accent);
  color: #fff;
}

.btn--primary {
  background: var(--color-accent);
  color: #fff;
}

.contact--simple {
  border-bottom: 0;
}

.contact-panel {
  max-width: 700px;
  margin: 0 auto;
  padding: 28px;
  border: 1px solid var(--color-border);
  background: var(--color-surface);
}

.contact-panel h2 {
  margin: 0 0 12px;
  font-size: 2rem;
}

.contact-panel p:not(.label) {
  margin: 0;
  color: var(--color-muted);
}

.contact-panel__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
  align-items: center;
  margin-top: 22px;
}

.contact-panel__links {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
}

.blog-article {
  max-width: 820px;
  padding-top: 72px;
  padding-bottom: 72px;
}

.article {
  max-width: 700px;
  margin: 0 auto;
}

.article h1 {
  margin: 0 0 18px;
  font-size: clamp(2.2rem, 6vw, 4rem);
  line-height: 1.1;
}

.article__author {
  margin: 0 0 42px;
  color: var(--color-muted);
  font-family: "Courier New", Courier, monospace;
  font-size: 0.85rem;
}

.article p,
.article li {
  font-size: 1.05rem;
}

.article p {
  margin: 0 0 22px;
}

.article h2 {
  margin: 46px 0 16px;
  font-size: 2rem;
  line-height: 1.2;
}

.article h3 {
  margin: 32px 0 12px;
  font-family: var(--font-body);
  font-size: 1.15rem;
  font-weight: bold;
}

.article ul,
.article ol {
  margin: 0 0 22px;
  padding-left: 28px;
}

.article li {
  margin-bottom: 8px;
}

.article pre {
  margin: 0 0 22px;
  padding: 16px;
  overflow-x: auto;
  border: 1px solid var(--color-border);
  background: #f5f8fc;
  color: #161a20;
  font-size: 0.9rem;
}

.article code {
  font-family: "Courier New", Courier, monospace;
}

.article-cta {
  max-width: 700px;
  margin: 50px auto 0;
  padding-top: 28px;
  border-top: 1px solid var(--color-border);
}

.article-cta h2 {
  margin: 0 0 10px;
  font-family: var(--font-heading);
  font-size: 1.8rem;
  font-weight: normal;
}

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

.site-footer {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 24px;
  border-top: 1px solid var(--color-border);
  color: var(--color-muted);
  font-size: 0.85rem;
}

.site-footer p {
  margin: 0;
}

.site-footer div {
  display: flex;
  gap: 16px;
}

.error-page {
  display: flex;
  min-height: 100vh;
  align-items: center;
  justify-content: center;
  text-align: center;
}

.error-container {
  max-width: 600px;
  padding: 2rem;
}

.error-container h1 {
  margin: 0;
  color: var(--color-accent);
  font-family: var(--font-heading);
  font-size: clamp(4rem, 15vw, 8rem);
  line-height: 1;
}

.error-container p {
  margin: 1rem 0 2rem;
  color: var(--color-muted);
  font-size: 1.2rem;
}

@media (max-width: 700px) {
  .site-header {
    align-items: flex-start;
  }

  .site-nav ul {
    gap: 12px;
    flex-wrap: wrap;
    justify-content: flex-end;
  }

  .theme-toggle {
    margin-top: 8px;
  }

  .hero {
    min-height: 400px;
    padding-top: 72px;
    padding-bottom: 72px;
  }

  .grid-container {
    grid-template-columns: 1fr;
    gap: 18px;
  }

  .content h2 {
    font-size: 2rem;
  }

  .blog-item {
    display: block;
  }

  .blog-item .date {
    display: block;
    margin-bottom: 4px;
  }

  .site-footer {
    flex-direction: column;
  }
}

@media (max-width: 420px) {
  .site-header,
  .hero,
  .section,
  .blog-article {
    padding-right: 16px;
    padding-left: 16px;
  }

  .site-header {
    display: flex;
    align-items: center;
    gap: 12px;
    min-height: 60px;
    padding-top: 8px;
    padding-bottom: 8px;
  }

  .site-nav {
    flex: 1;
    min-width: 0;
  }

  .site-nav ul {
    gap: 4px;
    justify-content: flex-start;
  }

  .site-nav a {
    display: inline-block;
    padding: 8px 4px;
    font-size: 0.75rem;
  }

  .theme-toggle {
    flex: 0 0 auto;
    min-height: 36px;
    margin-top: 0;
    padding: 5px 7px;
    font-size: 0.7rem;
  }

  .hero {
    min-height: 320px;
    padding-top: 56px;
    padding-bottom: 56px;
  }

  .hero__content h1 {
    margin-bottom: 16px;
    font-size: clamp(2.5rem, 13vw, 3rem);
  }

  .hero__sub {
    font-size: 1rem;
  }

  .section,
  .blog-article {
    padding-top: 48px;
    padding-bottom: 48px;
  }

  .grid-container {
    gap: 14px;
  }

  .content h2 {
    margin-bottom: 16px;
    font-size: 1.8rem;
  }

  .content p {
    margin-bottom: 16px;
  }

  .blog-item {
    padding: 14px 0;
  }

  .blog-item:hover,
  .blog-item:focus {
    padding-left: 4px;
  }

  .blog-item .title {
    display: block;
    overflow-wrap: anywhere;
  }

  .contact-panel {
    padding: 18px;
  }

  .contact-panel h2 {
    font-size: 1.8rem;
  }

  .contact-panel__actions,
  .contact-panel__links {
    align-items: flex-start;
    flex-direction: column;
    gap: 12px;
  }

  .btn {
    min-height: 40px;
    padding: 9px 14px;
  }

  .article h1 {
    font-size: clamp(2rem, 10vw, 2.5rem);
  }

  .article__author {
    margin-bottom: 28px;
    font-size: 0.78rem;
  }

  .article p,
  .article li {
    font-size: 1rem;
  }

  .article h2 {
    margin-top: 36px;
    font-size: 1.7rem;
  }

  .article pre {
    margin-right: -4px;
    margin-left: -4px;
    padding: 12px;
    font-size: 0.78rem;
  }

  .site-footer {
    padding: 20px 16px;
  }

  .site-footer div {
    flex-wrap: wrap;
    gap: 12px;
  }
}