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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-family);
  background: var(--color-bg-base);
  color: var(--color-text-primary);
  line-height: var(--line-height-normal);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

/* ===== Typography ===== */
h1, h2, h3, h4, h5, h6 {
  line-height: var(--line-height-tight);
  margin-bottom: var(--space-sm);
  font-weight: var(--font-weight-bold);
  letter-spacing: var(--letter-spacing-tight);
}

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

h2 {
  font-size: var(--font-size-h2);
}

h3 {
  font-size: var(--font-size-h3);
}

h4 {
  font-size: var(--font-size-h4);
}

p {
  margin-bottom: var(--space-md);
}

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

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

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

ul, ol {
  list-style: none;
}

/* ===== Container & Layout ===== */
.container {
  width: 100%;
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: 0 var(--container-padding);
}

.section {
  padding: var(--space-2xl) 0;
}

.section-title {
  text-align: center;
  margin-bottom: var(--space-md);
  color: var(--color-text-primary);
}

.section-subtitle {
  text-align: center;
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-xl);
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

/* ===== Header & Navigation ===== */
.header {
  position: sticky;
  top: 0;
  background: var(--color-bg-dark);
  box-shadow: var(--shadow-flat);
  z-index: var(--z-sticky);
  backdrop-filter: blur(var(--blur-lg));
  border-bottom: var(--border-subtle);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-md) var(--container-padding);
  gap: var(--space-lg);
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-primary);
  text-decoration: none;
  transition: all var(--transition-fast);
}

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

.logo img {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-sm);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
  flex: 1;
  justify-content: center;
}

.nav-links a {
  color: var(--color-text-secondary);
  font-weight: var(--font-weight-medium);
  transition: all var(--transition-fast);
  position: relative;
}

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

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--color-primary), var(--color-accent));
  transition: width var(--transition-base);
}

.nav-links a:hover::after {
  width: 100%;
}

.btn-nav-github {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  padding: var(--space-xs) var(--space-md);
  background: var(--color-surface);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-flat);
  border-top: var(--border-highlight);
  transition: all var(--transition-base);
}

.btn-nav-github:hover {
  box-shadow: var(--shadow-raised);
  transform: translateY(-2px);
}

.lang-toggle {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  padding: var(--space-xs) var(--space-md);
  background: var(--color-surface);
  border: none;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-flat);
  color: var(--color-text-primary);
  cursor: pointer;
  transition: all var(--transition-base);
  border-top: var(--border-highlight);
  font-family: var(--font-family);
  font-weight: var(--font-weight-medium);
}

.lang-toggle:hover {
  box-shadow: var(--shadow-raised);
  transform: translateY(-2px);
}

.lang-current {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-semibold);
}

/* Mobile Menu Toggle */
.mobile-menu-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: transparent;
  border: none;
  cursor: pointer;
  padding: var(--space-xs);
}

.mobile-menu-toggle span {
  width: 24px;
  height: 3px;
  background: var(--color-text-primary);
  border-radius: var(--radius-full);
  transition: all var(--transition-base);
}

.mobile-menu-toggle[aria-expanded="true"] span:nth-child(1) {
  transform: rotate(45deg) translate(7px, 7px);
}

.mobile-menu-toggle[aria-expanded="true"] span:nth-child(2) {
  opacity: 0;
}

.mobile-menu-toggle[aria-expanded="true"] span:nth-child(3) {
  transform: rotate(-45deg) translate(7px, -7px);
}

/* ===== Language Dropdown ===== */
.lang-dropdown {
  position: fixed;
  top: 70px;
  right: var(--space-md);
  background: var(--color-surface);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-raised-large);
  padding: var(--space-sm);
  z-index: var(--z-dropdown);
  min-width: 200px;
  opacity: 0;
  transform: translateY(-10px);
  transition: all var(--transition-base);
  pointer-events: none;
}

.lang-dropdown[aria-hidden="false"] {
  opacity: 1;
  transform: translateY(0);
  pointer-events: all;
}

.lang-option {
  width: 100%;
  padding: var(--space-sm) var(--space-md);
  background: transparent;
  border: none;
  border-radius: var(--radius-sm);
  color: var(--color-text-primary);
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  text-align: left;
  cursor: pointer;
  transition: all var(--transition-fast);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.lang-option:hover {
  background: var(--color-bg-light);
  color: var(--color-primary);
}

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

/* ===== Hero Section ===== */
.hero {
  min-height: 90vh;
  display: flex;
  align-items: center;
  padding: var(--space-2xl) 0;
  background: linear-gradient(
    135deg,
    var(--color-bg-base) 0%,
    var(--color-bg-dark) 50%,
    var(--color-bg-base) 100%
  );
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -10%;
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, rgba(74, 158, 255, 0.1), transparent);
  border-radius: var(--radius-full);
  pointer-events: none;
}

.hero-container {
  display: grid;
  grid-template-columns: 1fr 1.5fr;
  gap: var(--space-2xl);
  align-items: center;
}

.hero-content {
  z-index: 1;
}

.hero-title {
  font-size: var(--font-size-h1);
  margin-bottom: var(--space-sm);
  background: linear-gradient(135deg, var(--color-text-primary), var(--color-primary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: var(--font-size-2xl);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-md);
}

.hero-description {
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
  line-height: var(--line-height-relaxed);
  margin-bottom: var(--space-lg);
  max-width: 500px;
}

.hero-badge {
  display: inline-block;
  padding: var(--space-sm) var(--space-lg);
  background: var(--color-surface);
  border-radius: var(--radius-full);
  box-shadow: var(--shadow-flat);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-semibold);
  color: var(--color-accent);
  margin-bottom: var(--space-xl);
  border-top: var(--border-highlight);
}

.hero-ctas {
  display: flex;
  gap: var(--space-md);
  flex-wrap: wrap;
}

.hero-demo {
  position: relative;
  z-index: 1;
}

.demo-video {
  width: 100%;
  max-width: 2400px;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-raised-large);
  border: 2px solid rgba(255, 255, 255, 0.05);
}

/* ===== Features Section ===== */
.features {
  padding: var(--space-3xl) 0;
  background: var(--color-bg-dark);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-lg);
}

/* ===== How It Works Section ===== */
.how-it-works {
  padding: var(--space-3xl) 0;
  background: var(--color-bg-base);
}

.steps-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-xl);
  position: relative;
}

/* Connecting line between steps on desktop */
.steps-grid::before {
  content: '';
  position: absolute;
  top: 50px;
  left: 16.66%;
  right: 16.66%;
  height: 2px;
  background: linear-gradient(90deg, var(--color-primary), var(--color-accent));
  opacity: 0.3;
  z-index: 0;
}

.step-card {
  z-index: 1;
}

/* ===== Privacy Section ===== */
.privacy {
  padding: var(--space-3xl) 0;
  background: var(--color-bg-dark);
}

.privacy-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-lg);
}

/* ===== FAQ Section ===== */
.faq {
  padding: var(--space-3xl) 0;
  background: var(--color-bg-base);
}

.faq-list {
  max-width: 800px;
  margin: 0 auto;
}

/* ===== CTA Section ===== */
.cta {
  padding: var(--space-3xl) 0;
  background: linear-gradient(
    135deg,
    var(--color-bg-dark) 0%,
    var(--color-bg-base) 50%,
    var(--color-bg-dark) 100%
  );
  text-align: center;
  position: relative;
  overflow: hidden;
}

.cta::before {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(74, 158, 255, 0.15), transparent);
  border-radius: var(--radius-full);
  pointer-events: none;
}

.cta-container {
  position: relative;
  z-index: 1;
}

.cta-buttons {
  display: flex;
  justify-content: center;
  gap: var(--space-md);
  flex-wrap: wrap;
  margin-top: var(--space-xl);
}

/* ===== Footer ===== */
.footer {
  padding: var(--space-2xl) 0 var(--space-lg);
  background: var(--color-bg-dark);
  border-top: var(--border-subtle);
}

.footer-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-lg);
  text-align: center;
}

.footer-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-sm);
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-primary);
}

.footer-brand img {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
}

.footer-tagline {
  color: var(--color-text-secondary);
  font-size: var(--font-size-base);
}

.footer-links {
  display: flex;
  gap: var(--space-lg);
  flex-wrap: wrap;
  justify-content: center;
}

.footer-links a {
  color: var(--color-text-secondary);
  font-size: var(--font-size-sm);
  transition: color var(--transition-fast);
}

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

.footer-copyright {
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
  margin: 0;
}

/* ===== Responsive Design ===== */

/* Large screens (1280px+) */
@media (min-width: 1280px) {
  .container {
    padding: 0 var(--space-xl);
  }
}

/* Desktop (1024px - 1279px) */
@media (max-width: 1279px) {
  .hero-container {
    gap: var(--space-xl);
  }

  .demo-video {
    max-width: 2000px;
  }
}

/* Tablet (768px - 1023px) */
@media (max-width: 1023px) {
  .nav-links {
    gap: var(--space-md);
  }

  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .steps-grid::before {
    display: none;
  }

  .privacy-grid {
    grid-template-columns: 1fr;
  }
}

/* Mobile landscape / Small tablet (640px - 767px) */
@media (max-width: 767px) {
  .header {
    position: fixed;
    width: 100%;
  }

  .nav {
    flex-wrap: nowrap;
    padding: var(--space-sm) var(--space-md);
    gap: var(--space-sm);
  }

  .logo {
    font-size: var(--font-size-lg);
    flex: 1;
  }

  .logo img {
    width: 32px;
    height: 32px;
  }

  .mobile-menu-toggle {
    display: flex;
    order: 3;
  }

  .lang-toggle {
    order: 2;
    padding: var(--space-xs) var(--space-sm);
    font-size: var(--font-size-sm);
  }

  .lang-toggle svg {
    width: 16px;
    height: 16px;
  }

  .lang-current {
    font-size: var(--font-size-xs);
  }

  .nav-links {
    position: fixed;
    top: 60px;
    left: 0;
    right: 0;
    background: var(--color-surface);
    flex-direction: column;
    padding: var(--space-lg);
    box-shadow: var(--shadow-raised-large);
    transform: translateY(-100%);
    transition: transform var(--transition-base);
    z-index: var(--z-dropdown);
    align-items: flex-start;
    opacity: 0;
    pointer-events: none;
  }

  .nav-links[aria-hidden="false"] {
    transform: translateY(0);
    opacity: 1;
    pointer-events: all;
  }

  .btn-nav-github {
    width: 100%;
    justify-content: center;
  }

  .lang-dropdown {
    top: 60px;
  }

  .hero {
    min-height: auto;
    padding: calc(60px + var(--space-xl)) 0 var(--space-xl) 0;
  }

  .hero-container {
    grid-template-columns: 1fr;
    gap: var(--space-xl);
  }

  .hero-content {
    text-align: center;
  }

  .hero-description {
    margin-left: auto;
    margin-right: auto;
  }

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

  .demo-video {
    max-width: 100%;
  }

  .features-grid {
    grid-template-columns: 1fr;
  }

  .steps-grid {
    grid-template-columns: 1fr;
    gap: var(--space-lg);
  }

  .section {
    padding: var(--space-xl) 0;
  }

  .features,
  .how-it-works,
  .privacy,
  .faq,
  .cta {
    padding: var(--space-xl) 0;
  }
}

/* Mobile portrait (< 640px) */
@media (max-width: 639px) {
  .nav {
    padding: var(--space-xs) var(--space-sm);
  }

  .logo {
    font-size: var(--font-size-base);
  }

  .logo img {
    width: 28px;
    height: 28px;
  }

  .logo span {
    display: none;
  }

  .lang-toggle {
    padding: var(--space-xs);
  }

  .hero {
    padding: calc(50px + var(--space-lg)) 0 var(--space-lg) 0;
  }

  .hero-title {
    font-size: var(--font-size-4xl);
  }

  .hero-subtitle {
    font-size: var(--font-size-xl);
  }

  .hero-ctas {
    flex-direction: column;
    width: 100%;
  }

  .hero-ctas .neo-button {
    width: 100%;
    justify-content: center;
  }

  .section-title {
    font-size: var(--font-size-3xl);
  }

  .section-subtitle {
    font-size: var(--font-size-base);
  }

  .cta-buttons {
    flex-direction: column;
    width: 100%;
    max-width: 400px;
    margin-left: auto;
    margin-right: auto;
  }

  .cta-buttons .neo-button {
    width: 100%;
    justify-content: center;
  }

  .footer-links {
    flex-direction: column;
    gap: var(--space-sm);
  }
}

/* ===== Accessibility Enhancements ===== */
@media (prefers-reduced-motion: reduce) {
  .hero::before,
  .cta::before {
    animation: none;
  }
}

/* Focus visible enhancement */
*:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

/* Print styles */
@media print {
  .header,
  .footer,
  .cta,
  .lang-toggle,
  .mobile-menu-toggle {
    display: none;
  }

  body {
    background: white;
    color: black;
  }

  .neo-card,
  .neo-button {
    box-shadow: none;
    border: 1px solid #ccc;
  }
}