:root {
  --color-bg: #ffffff;
  --color-surface: #f8fafc;
  --color-surface-dark: #0f172a;
  --color-text: #1e293b;
  --color-text-muted: #64748b;
  --color-text-light: #94a3b8;
  --color-border: #e2e8f0;
  --color-accent: #2563eb;
  --color-accent-hover: #1d4ed8;
  --font-sans: "Segoe UI", system-ui, -apple-system, sans-serif;
  --max-width: 960px;
  --nav-height: 64px;
  --radius: 12px;
  --shadow-sm: 0 1px 3px rgba(15, 23, 42, 0.06);
  --shadow-md: 0 4px 20px rgba(15, 23, 42, 0.08);
  --transition: 0.25s ease;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--nav-height) + 16px);
  overflow-x: clip;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.7;
  background: var(--color-bg);
  color: var(--color-text);
  -webkit-font-smoothing: antialiased;
}

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

a {
  color: var(--color-accent);
  transition: color var(--transition);
}

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

/* NAV */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  height: var(--nav-height);
  padding: 0 clamp(1.25rem, 4vw, 2.5rem);
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  transition: box-shadow var(--transition);
}

.nav.scrolled {
  box-shadow: var(--shadow-sm);
}

.nav-brand {
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--color-text);
  text-decoration: none;
  letter-spacing: -0.01em;
  white-space: nowrap;
}

.nav-brand:hover {
  color: var(--color-accent);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: clamp(0.75rem, 2vw, 1.5rem);
}

.nav-links a {
  font-size: 0.875rem;
  color: var(--color-text-muted);
  text-decoration: none;
  white-space: nowrap;
}

.nav-links a:hover {
  color: var(--color-text);
}

.nav-lang {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-left: 0.5rem;
  padding-left: 1rem;
  border-left: 1px solid var(--color-border);
}

.nav-lang a {
  font-size: 0.8125rem;
  font-weight: 500;
  padding: 0.25rem 0.5rem;
  border-radius: 6px;
  color: var(--color-text-muted);
  text-decoration: none;
}

.nav-lang a.active,
.nav-lang a[aria-current="page"] {
  color: var(--color-accent);
  background: rgba(37, 99, 235, 0.08);
}

.nav-divider {
  color: var(--color-border);
  font-size: 0.75rem;
  user-select: none;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 36px;
  height: 36px;
  padding: 0;
  border: none;
  background: transparent;
  cursor: pointer;
}

.nav-toggle span {
  display: block;
  width: 20px;
  height: 2px;
  margin: 0 auto;
  background: var(--color-text);
  border-radius: 1px;
  transition: transform var(--transition), opacity var(--transition);
}

.nav-toggle.open span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav-toggle.open span:nth-child(2) {
  opacity: 0;
}

.nav-toggle.open span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* HERO */
.hero {
  background: linear-gradient(160deg, #0f172a 0%, #1e293b 100%);
  color: #f8fafc;
  padding: clamp(3rem, 8vw, 5rem) clamp(1.25rem, 4vw, 2.5rem);
}

.hero-inner {
  display: flex;
  align-items: center;
  gap: clamp(2rem, 5vw, 3.5rem);
  max-width: var(--max-width);
  margin: 0 auto;
}

.hero-image {
  flex-shrink: 0;
}

.hero-image img {
  width: clamp(140px, 28vw, 200px);
  height: clamp(140px, 28vw, 200px);
  object-fit: cover;
  border-radius: 50%;
  border: 3px solid rgba(255, 255, 255, 0.15);
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
}

.hero-content {
  flex: 1;
  min-width: 0;
}

.hero-content h1 {
  margin: 0 0 0.75rem;
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.2;
}

.subtitle {
  margin: 0 0 0.5rem;
  font-size: clamp(0.95rem, 2vw, 1.1rem);
  font-weight: 500;
  color: #cbd5e1;
}

.tagline {
  margin: 0;
  font-size: clamp(0.875rem, 1.8vw, 1rem);
  color: #94a3b8;
  max-width: 36em;
  line-height: 1.6;
}

/* SECTIONS */
.section {
  padding: 0;
}

.section-inner {
  width: 100%;
  max-width: var(--max-width);
  margin-inline: auto;
  padding: clamp(3rem, 6vw, 4.5rem) clamp(1.25rem, 4vw, 2.5rem);
}

.section.dark {
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}

.section-inner h2 {
  margin: 0 0 1.25rem;
  font-size: clamp(1.25rem, 2.5vw, 1.5rem);
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--color-text);
}

.section-inner h3 {
  margin: 0 0 0.5rem;
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-text);
}

.section-inner > p {
  margin: 0 0 1rem;
  color: var(--color-text-muted);
}

.section-inner > p:last-child {
  margin-bottom: 0;
}

.note {
  padding: 0.875rem 1rem;
  margin-bottom: 1.5rem;
  font-size: 0.9375rem;
  color: var(--color-text-muted);
  background: var(--color-surface);
  border-left: 3px solid var(--color-accent);
  border-radius: 0 var(--radius) var(--radius) 0;
}

.section.dark .note {
  background: var(--color-bg);
}

/* GRID & CARDS */
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.25rem;
  margin-top: 0.5rem;
}

.card {
  padding: 1.25rem 1.5rem;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition), transform var(--transition);
}

.section:not(.dark) .card {
  background: var(--color-surface);
}

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

.card h3 {
  margin: 0 0 0.75rem;
  font-size: 0.9375rem;
  font-weight: 600;
}

.card p {
  margin: 0;
  font-size: 0.9375rem;
  color: var(--color-text-muted);
  line-height: 1.6;
}

.card ul {
  margin: 0;
  padding-left: 1.125rem;
  font-size: 0.9375rem;
  color: var(--color-text-muted);
}

.card li {
  margin-bottom: 0.35rem;
}

.card li:last-child {
  margin-bottom: 0;
}

/* HIGHLIGHT */
.highlight {
  padding: 1.5rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
}

.highlight p {
  margin: 0 0 0.875rem;
  color: var(--color-text-muted);
}

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

.section.dark .highlight {
  background: var(--color-bg);
}

/* BUTTON */
.section-actions {
  margin-top: 1.5rem;
}

.button {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.625rem 1.25rem;
  font-size: 0.875rem;
  font-weight: 500;
  color: #fff;
  text-decoration: none;
  background: var(--color-accent);
  border-radius: 8px;
  transition: background var(--transition), transform var(--transition);
}

.button:hover {
  color: #fff;
  background: var(--color-accent-hover);
  transform: translateY(-1px);
}

/* FOOTER */
footer {
  text-align: center;
  padding: 2rem 1.25rem;
  font-size: 0.8125rem;
  color: var(--color-text-light);
  border-top: 1px solid var(--color-border);
}

/* FADE IN */
.fade {
  opacity: 0;
  transition: opacity 0.6s ease;
}

.fade.show {
  opacity: 1;
}

/* RESPONSIVE */
@media (max-width: 768px) {
  .nav-toggle {
    display: flex;
  }

  .nav-links {
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 0.75rem 0;
    background: rgba(255, 255, 255, 0.98);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-md);
    transform: translateY(-110%);
    opacity: 0;
    visibility: hidden;
    transition: transform var(--transition), opacity var(--transition), visibility var(--transition);
  }

  .nav-links.open {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }

  .nav-links a {
    padding: 0.75rem 1.5rem;
  }

  .nav-links a:hover {
    background: var(--color-surface);
  }

  .nav-lang {
    margin: 0.5rem 1.5rem 0;
    padding: 0.75rem 0 0;
    border-left: none;
    border-top: 1px solid var(--color-border);
    justify-content: center;
  }

  .hero-inner {
    flex-direction: column;
    text-align: center;
  }

  .tagline {
    margin-left: auto;
    margin-right: auto;
  }
}