:root {
  --color-primary: #1a73e8;
  --color-primary-dark: #1557b0;
  --color-primary-light: #e8f0fe;
  --color-secondary: #34a853;
  --color-accent: #fbbc04;
  --color-bg: #ffffff;
  --color-bg-alt: #f8f9fa;
  --color-bg-dark: #0f172a;
  --color-text: #202124;
  --color-text-secondary: #5f6368;
  --color-text-light: #ffffff;
  --color-border: #dadce0;
  --color-border-light: #e8eaed;
  --color-card: #ffffff;
  --color-card-shadow: rgba(0, 0, 0, 0.08);
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-xl: 28px;
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.06);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.12);
  --shadow-xl: 0 16px 48px rgba(0, 0, 0, 0.16);
  --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC',
    'Hiragino Sans GB', 'Microsoft YaHei', 'Helvetica Neue', Arial, sans-serif;
  --font-mono: 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, monospace;
  --transition-fast: 0.15s ease;
  --transition-base: 0.25s ease;
  --transition-slow: 0.4s cubic-bezier(0.4, 0, 0.2, 1);
  --container-max: 1200px;
  --container-padding: 24px;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg);
  overflow-x: hidden;
}

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

a:hover {
  color: var(--color-primary-dark);
}

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

button {
  cursor: pointer;
  font-family: inherit;
  border: none;
  background: none;
}

ul,
ol {
  list-style: none;
}

h1,
h2,
h3,
h4,
h5,
h6 {
  font-weight: 700;
  line-height: 1.3;
  color: var(--color-text);
}

h1 {
  font-size: 2.75rem;
}

h2 {
  font-size: 2.25rem;
}

h3 {
  font-size: 1.75rem;
}

h4 {
  font-size: 1.25rem;
}

p {
  margin-bottom: 1rem;
}

.container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--container-padding);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 28px;
  font-size: 1rem;
  font-weight: 600;
  border-radius: var(--radius-md);
  transition: all var(--transition-base);
  cursor: pointer;
  white-space: nowrap;
}

.btn-primary {
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
  color: var(--color-text-light);
  box-shadow: 0 4px 12px rgba(26, 115, 232, 0.35);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(26, 115, 232, 0.45);
  color: var(--color-text-light);
}

.btn-secondary {
  background: transparent;
  color: var(--color-primary);
  border: 2px solid var(--color-primary);
}

.btn-secondary:hover {
  background: var(--color-primary-light);
  transform: translateY(-2px);
}

.btn-white {
  background: var(--color-text-light);
  color: var(--color-primary);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

.btn-white:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.2);
}

.btn-ghost {
  background: transparent;
  color: var(--color-text-light);
  border: 2px solid rgba(255, 255, 255, 0.4);
}

.btn-ghost:hover {
  background: rgba(255, 255, 255, 0.1);
  border-color: var(--color-text-light);
  color: var(--color-text-light);
}

.section {
  padding: 80px 0;
}

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

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

.section-header {
  text-align: center;
  margin-bottom: 48px;
}

.section-header .subtitle {
  display: inline-block;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--color-primary);
  text-transform: uppercase;
  letter-spacing: 1.5px;
  margin-bottom: 12px;
}

.section-dark .section-header .subtitle {
  color: #60a5fa;
}

.section-header h2 {
  font-size: 2.25rem;
  margin-bottom: 12px;
}

.section-header p {
  font-size: 1.0625rem;
  color: var(--color-text-secondary);
  max-width: 640px;
  margin: 0 auto;
}

.section-dark .section-header p {
  color: rgba(255, 255, 255, 0.7);
}

.tag {
  display: inline-block;
  padding: 4px 12px;
  font-size: 0.75rem;
  font-weight: 600;
  border-radius: 100px;
  background: var(--color-primary-light);
  color: var(--color-primary);
}

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

.mb-0 {
  margin-bottom: 0;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border-light);
  transition: all var(--transition-base);
}

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

.nav-container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--container-padding);
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--color-text);
}

.nav-logo-img {
  display: block;
  height: 40px;
  width: auto;
  object-fit: contain;
}

.nav-logo-text {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
}

.nav-logo-name {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text);
}

.nav-logo-domain {
  font-size: 0.6875rem;
  font-weight: 500;
  color: var(--color-text-secondary);
  letter-spacing: 0.02em;
}

.nav-logo-icon {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  background: linear-gradient(135deg, var(--color-primary), #6c63ff);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-weight: 800;
  font-size: 1rem;
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 4px;
}

.nav-menu a {
  display: block;
  padding: 8px 16px;
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--color-text);
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}

.nav-menu a:hover {
  color: var(--color-primary);
  background-color: var(--color-primary-light);
}

.nav-menu a.active {
  color: var(--color-primary);
  font-weight: 600;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

.nav-actions .btn {
  padding: 8px 20px;
  font-size: 0.875rem;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 8px;
}

.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: all var(--transition-base);
}

.footer {
  background: var(--color-bg-dark);
  color: var(--color-text-light);
  padding: 64px 0 0;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr repeat(4, 1fr);
  gap: 48px;
  margin-bottom: 48px;
}

.footer-brand p {
  color: rgba(255, 255, 255, 0.6);
  font-size: 0.9375rem;
  max-width: 320px;
}

.footer h4 {
  color: var(--color-text-light);
  font-size: 0.9375rem;
  margin-bottom: 20px;
  text-transform: uppercase;
  letter-spacing: 1px;
}

.footer-column ul {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.footer-column a {
  color: rgba(255, 255, 255, 0.6);
  font-size: 0.9375rem;
  transition: color var(--transition-fast);
}

.footer-column a:hover {
  color: var(--color-text-light);
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding: 24px 0;
  text-align: center;
  color: rgba(255, 255, 255, 0.5);
  font-size: 0.875rem;
}

@media (max-width: 960px) {
  h1 {
    font-size: 2rem;
  }

  h2 {
    font-size: 1.75rem;
  }

  .section {
    padding: 56px 0;
  }

  .nav-menu {
    position: fixed;
    top: 68px;
    left: 0;
    right: 0;
    background: var(--color-bg);
    flex-direction: column;
    padding: 16px;
    gap: 4px;
    box-shadow: var(--shadow-lg);
    transform: translateY(-120%);
    transition: transform var(--transition-slow);
  }

  .nav-menu.open {
    transform: translateY(0);
  }

  .nav-menu a {
    width: 100%;
    padding: 12px 16px;
  }

  .nav-actions {
    display: none;
  }

  .nav-toggle {
    display: flex;
  }

  .footer-grid {
    grid-template-columns: 1fr 1fr 1fr;
    gap: 32px;
  }
}

@media (max-width: 560px) {
  h1 {
    font-size: 1.75rem;
  }

  h2 {
    font-size: 1.5rem;
  }

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

  .nav-logo-domain {
    display: none;
  }
}