:root {
  color-scheme: light;
  --font-sans: "Inter", "Segoe UI", system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: "Fira Code", "SFMono-Regular", Menlo, Consolas, "Liberation Mono", monospace;

  --step--1: clamp(0.78rem, 0.74rem + 0.22vw, 0.85rem);
  --step-0: clamp(0.95rem, 0.9rem + 0.28vw, 1rem);
  --step-1: clamp(1.1rem, 1rem + 0.6vw, 1.35rem);
  --step-2: clamp(1.35rem, 1.2rem + 1vw, 1.75rem);
  --step-3: clamp(1.7rem, 1.45rem + 1.6vw, 2.3rem);
  --step-4: clamp(2.15rem, 1.7rem + 2.6vw, 3rem);

  --fw-regular: 400;
  --fw-medium: 500;
  --fw-semibold: 600;
  --fw-bold: 700;

  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.5rem;
  --space-6: 2rem;
  --space-7: 3rem;

  --radius-pill: 999px;
  --radius-lg: 1rem;
  --radius-md: 0.75rem;
  --radius-sm: 0.5rem;

  --shadow-elevated: 0 18px 40px rgba(15, 23, 42, 0.12);
  --shadow-soft: 0 10px 25px rgba(15, 23, 42, 0.08);

  --color-background: #f8fafc;
  --color-background-alt: #e7f6ff;
  --color-surface: #ffffff;
  --color-hero-text: #ffffff;
  --color-text: #1f2933;
  --color-heading: #0f172a;
  --color-muted: #475569;
  --color-border: rgba(15, 23, 42, 0.12);
  --color-accent: #4cb6ea;
  --color-accent-strong: #ecc42e;
  --color-accent-soft: rgba(76, 182, 234, 0.18);
  --color-hero-overlay: rgba(17, 24, 39, 0.35);
  --gradient-hero: linear-gradient(140deg, #4cb6ea, #ecc42e 55%, #dc2626);
  --gradient-footer: linear-gradient(120deg, #0f172a, #4cb6ea 45%, #ecc42e);
}

body[data-theme="dark"] {
  --color-background: #0b1120;
  --color-background-alt: #0e1f30;
  --color-surface: #111827;
  --color-hero-text: #e2e8f0;
  --color-text: #e2e8f0;
  --color-heading: #f8fafc;
  --color-muted: #9dd9f2;
  --color-border: rgba(148, 163, 184, 0.3);
  --color-accent: #4cb6ea;
  --color-accent-strong: #ecc42e;
  --color-accent-soft: rgba(76, 182, 234, 0.28);
  --color-hero-overlay: rgba(15, 23, 42, 0.55);
  --gradient-hero: linear-gradient(140deg, #4cb6ea, #ecc42e 60%, #dc2626);
  --gradient-footer: linear-gradient(135deg, #030712, #0b2a3d 55%, #ecc42e);
  --shadow-elevated: 0 25px 45px rgba(0, 0, 0, 0.35);
  --shadow-soft: 0 18px 30px rgba(2, 6, 23, 0.4);
}

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

html {
  font-size: 100%;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  line-height: 1.6;
  color: var(--color-text);
  background: var(--color-background);
  transition: background 0.4s ease, color 0.3s ease;
}

.skip-link {
  position: absolute;
  top: -100px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--color-accent-strong);
  color: var(--color-surface);
  padding: var(--space-3) var(--space-5);
  border-radius: var(--radius-pill);
  font-weight: var(--fw-semibold);
  text-decoration: none;
  transition: top 0.2s ease;
}

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

body:focus-within {
  scroll-behavior: smooth;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: rgba(248, 250, 252, 0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  transition: background 0.4s ease, border-color 0.3s ease;
}

body[data-theme="dark"] .site-header {
  background: rgba(11, 17, 32, 0.92);
}

.site-header__inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: var(--space-3) var(--space-4);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
}

.site-brand {
  margin: 0;
  font-size: var(--step-1);
  font-weight: var(--fw-bold);
  color: var(--color-heading);
}

.theme-toggle {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  border: 1px solid var(--color-border);
  background: var(--color-surface);
  color: inherit;
  padding: var(--space-2) var(--space-4);
  border-radius: var(--radius-pill);
  cursor: pointer;
  font-size: var(--step--1);
  font-weight: var(--fw-medium);
  transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease, border 0.2s ease;
}

.theme-toggle:hover,
.theme-toggle:focus {
  transform: translateY(-1px);
  box-shadow: var(--shadow-soft);
}

.theme-toggle:focus-visible {
  outline: 3px solid var(--color-accent-strong);
  outline-offset: 3px;
}

.theme-toggle__icon {
  font-size: 1.1rem;
}

.hero {
  position: relative;
  background: var(--gradient-hero);
  color: var(--color-hero-text);
  padding: var(--space-7) var(--space-4) calc(var(--space-7) + var(--space-2));
  overflow: hidden;
}

.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: radial-gradient(circle at 15% 20%, rgba(255, 255, 255, 0.18), transparent 55%),
    radial-gradient(circle at 85% 15%, rgba(255, 255, 255, 0.12), transparent 45%),
    linear-gradient(120deg, transparent 0 60%, rgba(255, 255, 255, 0.18));
  opacity: 0.6;
}

.hero::after {
  content: "";
  position: absolute;
  inset: 0;
  background: var(--color-hero-overlay);
  mix-blend-mode: soft-light;
}

.hero-inner {
  position: relative;
  z-index: 1;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-7);
  max-width: 1100px;
  margin: 0 auto;
}

.hero-content {
  flex: 1 1 540px;
}

.hero-subtitle {
  font-size: var(--step-1);
  font-weight: var(--fw-medium);
  max-width: 54ch;
}

.hero-highlights {
  list-style: none;
  padding: 0;
  margin: var(--space-4) 0 var(--space-5);
  display: grid;
  gap: var(--space-3);
}

.hero-highlights li {
  position: relative;
  padding-left: calc(var(--space-5) + var(--space-2));
  font-weight: var(--fw-semibold);
}

.hero-highlights li::before {
  content: "✔";
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  background: rgba(15, 23, 42, 0.3);
  width: 1.6rem;
  height: 1.6rem;
  border-radius: var(--radius-pill);
  display: grid;
  place-items: center;
  font-size: 0.95rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
}

.cta {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-3) var(--space-5);
  border-radius: var(--radius-pill);
  font-weight: var(--fw-bold);
  text-decoration: none;
  transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease, color 0.2s ease;
  box-shadow: 0 15px 35px rgba(15, 23, 42, 0.2);
}

.cta.primary {
  background: var(--color-surface);
  color: var(--color-heading);
}

.cta.secondary {
  background: rgba(15, 23, 42, 0.3);
  color: var(--color-surface);
  border: 2px solid rgba(255, 255, 255, 0.4);
}

.cta:hover,
.cta:focus {
  transform: translateY(-2px);
  text-decoration: none;
}

.cta.primary:hover,
.cta.primary:focus {
  background: #e2e8f0;
}

.cta.secondary:hover,
.cta.secondary:focus {
  background: rgba(15, 23, 42, 0.5);
}

.cta:focus-visible {
  outline: 3px solid rgba(255, 255, 255, 0.7);
  outline-offset: 3px;
}

.hero-media {
  flex: 0 0 280px;
  min-height: 240px;
  border-radius: 1.5rem;
  background: transparent;
  box-shadow: 0 18px 40px rgba(15, 23, 42, 0.35);
  position: relative;
  overflow: hidden;
  display: grid;
  place-items: center;
  padding: var(--space-4);
}

.hero-media img {
  width: 100%;
  max-width: 220px;
  height: auto;
  filter: drop-shadow(0 12px 24px rgba(15, 23, 42, 0.35));
}



.site-nav {
  background: var(--color-surface);
  box-shadow: var(--shadow-elevated);
  margin: calc(-1 * var(--space-6)) auto var(--space-7);
  max-width: 1000px;
  padding: var(--space-3) var(--space-5);
  border-radius: var(--radius-lg);
  transition: background 0.4s ease, box-shadow 0.4s ease;
}

.site-nav ul {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--space-3);
  margin: 0;
  padding: 0;
}

.site-nav a {
  color: var(--color-heading);
  font-weight: var(--fw-semibold);
  font-size: var(--step--1);
}

footer {
  background: var(--gradient-footer);
  color: var(--color-surface);
  padding: var(--space-6) var(--space-4);
  text-align: center;
  position: relative;
  overflow: hidden;
}

footer::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: radial-gradient(circle at 20% 30%, rgba(255, 255, 255, 0.12), transparent 60%),
    radial-gradient(circle at 80% 70%, rgba(216, 180, 254, 0.18), transparent 50%);
  opacity: 0.7;
}

footer > * {
  position: relative;
  z-index: 1;
}

main {
  padding: var(--space-6) var(--space-4) var(--space-7);
  max-width: 960px;
  margin: 0 auto;
}

section {
  background: var(--color-surface);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-elevated);
  padding: var(--space-5);
  margin-bottom: var(--space-6);
  transition: background 0.4s ease, box-shadow 0.4s ease;
}

h1,
h2,
h3 {
  color: var(--color-heading);
  line-height: 1.25;
  margin-top: 0;
  font-family: var(--font-sans);
}

h1 {
  font-size: var(--step-4);
}

h2 {
  font-size: var(--step-2);
  margin-bottom: var(--space-3);
}

h3 {
  font-size: var(--step-1);
  margin-bottom: var(--space-2);
}

p {
  margin: 0 0 var(--space-4);
  font-size: var(--step-0);
  color: var(--color-text);
}

ul,
ol {
  padding-left: calc(var(--space-5) + var(--space-2));
  margin: 0 0 var(--space-4);
}

li + li {
  margin-top: var(--space-2);
}

a {
  color: var(--color-accent);
  font-weight: var(--fw-semibold);
  text-decoration: none;
  transition: color 0.2s ease;
}

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

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

pre,
code,
kbd {
  font-family: var(--font-mono);
}

pre {
  background: var(--color-heading);
  color: var(--color-surface);
  border-radius: var(--radius-sm);
  padding: var(--space-4);
  overflow-x: auto;
  margin: var(--space-4) 0;
}

code {
  background: var(--color-accent-soft);
  padding: 0.2rem 0.45rem;
  border-radius: var(--radius-sm);
  font-size: 0.95em;
}

pre code {
  background: none;
  padding: 0;
  border-radius: 0;
  font-size: 0.95em;
}

kbd {
  display: inline-block;
  background: rgba(15, 23, 42, 0.12);
  border: 1px solid rgba(15, 23, 42, 0.2);
  border-radius: var(--radius-sm);
  padding: 0.15rem 0.5rem;
  font-size: 0.9em;
  box-shadow: inset 0 -1px 0 rgba(15, 23, 42, 0.15);
}

footer p {
  margin: 0;
  font-weight: var(--fw-medium);
}

.feature-grid,
.architecture-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: var(--space-5);
  margin-bottom: var(--space-5);
}

.feature-card,
.architecture-card {
  background: var(--color-background);
  border-radius: var(--radius-md);
  padding: var(--space-5);
  box-shadow: var(--shadow-soft);
  transition: transform 0.2s ease, box-shadow 0.25s ease, background 0.3s ease;
  display: grid;
  gap: var(--space-3);
}

.feature-card:hover,
.feature-card:focus-within,
.architecture-card:hover,
.architecture-card:focus-within {
  transform: translateY(-4px);
  box-shadow: 0 25px 45px rgba(15, 23, 42, 0.18);
}

.feature-card__icon,
.architecture-card__icon {
  font-size: var(--step-3);
}

.feature-card h3,
.architecture-card h3 {
  margin: 0;
}

.data-tag {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: 0.35rem 0.75rem;
  border-radius: var(--radius-pill);
  background: var(--color-accent-soft);
  color: var(--color-accent-strong);
  font-weight: var(--fw-semibold);
  font-size: var(--step--1);
  letter-spacing: 0.01em;
}

.tag-strip {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-bottom: var(--space-4);
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: var(--step--1);
  box-shadow: var(--shadow-soft);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.data-table th,
.data-table td {
  padding: var(--space-3) var(--space-4);
  text-align: left;
  border-bottom: 1px solid var(--color-border);
}

.data-table thead th {
  background: var(--color-background-alt);
  font-weight: var(--fw-semibold);
  color: var(--color-heading);
  font-size: var(--step-0);
}

.data-table tbody tr:nth-child(even) {
  background: rgba(147, 51, 234, 0.08);
}

body[data-theme="dark"] .data-table tbody tr:nth-child(even) {
  background: rgba(192, 132, 252, 0.18);
}

.decorated-list {
  list-style: none;
  padding-left: 0;
}

.decorated-list li {
  position: relative;
  padding-left: calc(var(--space-4) + var(--space-2));
}

.decorated-list li::before {
  content: "•";
  position: absolute;
  left: 0;
  top: 0.35em;
  font-size: 1.5em;
  line-height: 1;
  color: var(--color-accent);
}

.callout {
  background: var(--color-background-alt);
  border-left: 4px solid var(--color-accent-strong);
  border-radius: var(--radius-md);
  padding: var(--space-4);
  box-shadow: var(--shadow-soft);
  margin-top: var(--space-5);
}

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

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

@media (max-width: 640px) {
  .site-header__inner {
    padding: var(--space-3);
  }

  .hero {
    padding: var(--space-6) var(--space-3) var(--space-6);
  }

  .hero-inner {
    flex-direction: column;
    text-align: center;
    gap: var(--space-5);
  }

  .hero-content {
    flex: 1;
  }

  .hero-highlights li {
    padding-left: 0;
  }

  .hero-highlights li::before {
    display: none;
  }

  .hero-actions {
    justify-content: center;
  }

  .hero-media {
    width: 100%;
    max-width: 320px;
  }

  main {
    padding: var(--space-5) var(--space-3) var(--space-6);
  }

  .site-nav {
    margin: calc(-1 * var(--space-5)) var(--space-3) var(--space-5);
  }

  section {
    padding: var(--space-4);
  }
}