:root {
  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, "Cascadia Code", "Source Code Pro", Menlo, Consolas, monospace;

  --color-bg: #fafafa;
  --color-surface: #ffffff;
  --color-surface-subtle: #f4f4f6;

  --color-text-primary: #121316;
  --color-text-secondary: #585a66;
  --color-text-muted: #8b8d98;

  --color-border: #e6e6eb;
  --color-border-hover: #d1d1db;

  --color-brand: #2563eb;
  --color-brand-hover: #1d4ed8;
  --color-brand-surface: #eff6ff;

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 4px 12px -2px rgba(0, 0, 0, 0.06), 0 2px 6px -1px rgba(0, 0, 0, 0.04);
  --shadow-lg: 0 12px 24px -4px rgba(0, 0, 0, 0.08), 0 4px 8px -2px rgba(0, 0, 0, 0.03);

  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-smooth: 250ms cubic-bezier(0.4, 0, 0.2, 1);

  --container-max-w: 1120px;
  --gutter: clamp(1rem, 4vw, 2rem);
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #0d0e11;
    --color-surface: #15171c;
    --color-surface-subtle: #1c1f26;

    --color-text-primary: #f2f3f5;
    --color-text-secondary: #9ca0ae;
    --color-text-muted: #646877;

    --color-border: #242731;
    --color-border-hover: #333846;

    --color-brand: #3b82f6;
    --color-brand-hover: #60a5fa;
    --color-brand-surface: #1e293b;

    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 12px -2px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 12px 24px -4px rgba(0, 0, 0, 0.6);
  }
}

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  background-color: var(--color-bg);
  color: var(--color-text-primary);
  line-height: 1.6;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.skip-link {
  position: absolute;
  top: -100%;
  left: 1rem;
  background: var(--color-brand);
  color: #ffffff;
  padding: 0.75rem 1.25rem;
  font-weight: 500;
  border-radius: var(--radius-sm);
  z-index: 1000;
  text-decoration: none;
  transition: top var(--transition-fast);
}

.skip-link:focus {
  top: 1rem;
}

.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;
}

h1, h2, h3 {
  color: var(--color-text-primary);
  line-height: 1.25;
  font-weight: 600;
  letter-spacing: -0.02em;
}

h1 {
  font-size: clamp(2rem, 5vw, 3.25rem);
}

h2 {
  font-size: clamp(1.5rem, 3.5vw, 2.25rem);
  margin-bottom: 1.5rem;
}

h3 {
  font-size: 1.25rem;
  margin-bottom: 0.5rem;
}

p {
  color: var(--color-text-secondary);
}

a {
  color: var(--color-brand);
  text-decoration: none;
  transition: color var(--transition-fast);
}

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

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

ul {
  list-style: none;
}

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

.site-header {
  position: sticky;
  top: 0;
  background-color: color-mix(in srgb, var(--color-bg) 85%, transparent);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  z-index: 100;
}

.navigation {
  max-width: var(--container-max-w);
  margin-inline: auto;
  padding: 1rem var(--gutter);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  font-weight: 700;
  font-size: 1.125rem;
  color: var(--color-text-primary);
  letter-spacing: -0.01em;
}

.nav-list {
  display: flex;
  gap: 1.75rem;
}

.nav-list a {
  color: var(--color-text-secondary);
  font-weight: 500;
  font-size: 0.9375rem;
  padding-block: 0.25rem;
  position: relative;
}

.nav-list a:hover,
.nav-list a[aria-current="page"] {
  color: var(--color-text-primary);
}

.nav-list a[aria-current="page"]::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 2px;
  background: var(--color-brand);
  border-radius: 1px;
}

.mobile-menu-toggle {
  display: none;
  background: transparent;
  border: none;
  font-size: 1.5rem;
  color: var(--color-text-primary);
  cursor: pointer;
}

main {
  flex: 1;
  width: 100%;
  max-width: var(--container-max-w);
  margin-inline: auto;
  padding: 3rem var(--gutter) 6rem;
  display: flex;
  flex-direction: column;
  gap: 5rem;
}

.hero-section {
  max-width: 48rem;
  padding-top: clamp(2rem, 6vw, 4.5rem);
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.lead {
  font-size: clamp(1.125rem, 2vw, 1.35rem);
  color: var(--color-text-secondary);
  line-height: 1.5;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.75rem 1.5rem;
  font-size: 0.9375rem;
  font-weight: 500;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  cursor: pointer;
  width: fit-content;
  transition: all var(--transition-fast);
}

.btn-primary {
  background-color: var(--color-brand);
  color: #ffffff;
}

.btn-primary:hover {
  background-color: var(--color-brand-hover);
  color: #ffffff;
  transform: translateY(-1px);
}

.btn-secondary {
  background-color: var(--color-surface);
  color: var(--color-text-primary);
  border-color: var(--color-border);
}

.btn-secondary:hover {
  border-color: var(--color-border-hover);
  background-color: var(--color-surface-subtle);
  transform: translateY(-1px);
}

.article-content {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: clamp(1.5rem, 3vw, 2.5rem);
  box-shadow: var(--shadow-sm);
}

.article-content ul {
  margin-top: 1.25rem;
  list-style-type: disc;
  padding-left: 1.25rem;
  color: var(--color-text-secondary);
}

.article-content li + li {
  margin-top: 0.5rem;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 300px), 1fr));
  gap: 1.5rem;
}

.feature-card {
  height: 100%;
  display: flex;
  flex-direction: column;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: border-color var(--transition-smooth), transform var(--transition-smooth), box-shadow var(--transition-smooth);
}

.feature-card:hover {
  border-color: var(--color-border-hover);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.feature-card figure {
  aspect-ratio: 16 / 10;
  overflow: hidden;
  background-color: var(--color-surface-subtle);
}

.feature-card img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--transition-smooth);
}

.feature-card:hover img {
  transform: scale(1.03);
}

.feature-card h3 {
  padding: 1.5rem 1.5rem 0.5rem;
}

.feature-card p {
  padding: 0 1.5rem 1.5rem;
  font-size: 0.9375rem;
}

.contact-section {
  max-width: 36rem;
}

form {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: clamp(1.5rem, 4vw, 2.5rem);
  box-shadow: var(--shadow-sm);
}

fieldset {
  border: none;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  margin-bottom: 1.5rem;
}

.form-field {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

label {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text-primary);
}

input, textarea {
  width: 100%;
  font-family: inherit;
  font-size: 0.9375rem;
  color: var(--color-text-primary);
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 0.625rem 0.875rem;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

input:focus, textarea:focus {
  outline: none;
  border-color: var(--color-brand);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--color-brand) 15%, transparent);
}

textarea {
  resize: vertical;
  min-height: 120px;
}

.site-footer {
  margin-top: auto;
  border-top: 1px solid var(--color-border);
  background-color: var(--color-surface);
  padding: 2.5rem var(--gutter);
}

.site-footer > * {
  max-width: var(--container-max-w);
  margin-inline: auto;
}

.site-footer nav {
  margin-bottom: 1rem;
}

.site-footer nav ul {
  display: flex;
  flex-wrap: wrap;
  gap: 1.5rem;
}

.site-footer a {
  color: var(--color-text-secondary);
  font-size: 0.875rem;
}

.site-footer a:hover {
  color: var(--color-text-primary);
}

.copyright {
  display: block;
  font-size: 0.8125rem;
  color: var(--color-text-muted);
  margin-top: 1.5rem;
}

@media (max-width: 640px) {
  .nav-list {
    display: none;
  }

  .mobile-menu-toggle {
    display: block;
  }

  main {
    gap: 3.5rem;
  }
}