:root {
  --color-bg: #ffffff;
  --color-text-primary: #111827;
  --color-text-secondary: #6b7280;
  --color-btn-bg: #111827;
  --color-btn-text: #ffffff;
  --shadow-light: 0 4px 12px rgba(0,0,0,0.05);
  --shadow-hover: 0 10px 20px rgba(0,0,0,0.1);
  --border-radius: 0.75rem;
  --spacing-section-vertical: 5rem;
  --font-headline: 'Poppins', sans-serif;
  --font-body: 'Poppins', sans-serif;
}

/* Reset and base */
*, *::before, *::after {
  box-sizing: border-box;
}
body {
  margin: 0;
  font-family: var(--font-body);
  background: var(--color-bg);
  color: var(--color-text-secondary);
  line-height: 1.6;
  font-size: 18px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a {
  color: inherit;
  text-decoration: none;
}

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

/* Container for max width and horizontal padding */
.container {
  max-width: 1200px;
  margin-left: auto;
  margin-right: auto;
  padding-left: 1rem;
  padding-right: 1rem;
}

/* Sticky Header */
.site-header {
  position: sticky;
  top: 0;
  background: rgba(255 255 255 / 0.95);
  backdrop-filter: saturate(180%) blur(10px);
  box-shadow: 0 1px 6px rgba(0,0,0,0.05);
  z-index: 10000;
}
.nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 4.5rem;
}
.logo {
  font-family: var(--font-headline);
  font-weight: 700;
  font-size: 1.75rem;
  color: var(--color-text-primary);
  user-select: none;
}
.nav-links {
  display: flex;
  gap: 2.5rem;
  font-weight: 600;
  font-size: 1rem;
  color: var(--color-text-secondary);
  transition: color 0.3s ease;
}
.nav-links a.nav-link:hover,
.nav-links a.nav-link:focus {
  color: var(--color-text-primary);
  outline: none;
}
.nav-cta {
  background-color: var(--color-btn-bg);
  color: var(--color-btn-text);
  padding: 0.5rem 1.75rem;
  border-radius: var(--border-radius);
  box-shadow: var(--shadow-light);
  transition: background-color 0.3s ease, transform 0.3s ease, box-shadow 0.3s ease;
  user-select: none;
}
.nav-cta:hover,
.nav-cta:focus {
  background-color: #000000;
  box-shadow: var(--shadow-hover);
  transform: scale(1.05);
  outline: none;
}

/* Hero Section */
.hero {
  padding-top: var(--spacing-section-vertical);
  padding-bottom: var(--spacing-section-vertical);
  text-align: center;
  color: var(--color-text-primary);
}
.hero-title {
  font-size: 4rem;
  font-weight: 800;
  margin-bottom: 1rem;
  line-height: 1.1;
  max-width: 900px;
  margin-left: auto;
  margin-right: auto;
}
.hero-subtitle {
  font-size: 1.375rem;
  margin-bottom: 3rem;
  max-width: 700px;
  margin-left: auto;
  margin-right: auto;
  color: var(--color-text-secondary);
}
.hero-cta {
  font-weight: 700;
  font-size: 1.25rem;
  padding: 1.25rem 3rem;
  border-radius: var(--border-radius);
  box-shadow: var(--shadow-light);
  transition: background-color 0.3s ease, transform 0.3s ease, box-shadow 0.3s ease;
  user-select: none;
  display: inline-block;
}
.hero-cta:hover,
.hero-cta:focus {
  background-color: #000000;
  box-shadow: var(--shadow-hover);
  transform: scale(1.05);
  outline: none;
}

/* Sections common styles */
section {
  padding-top: var(--spacing-section-vertical);
  padding-bottom: var(--spacing-section-vertical);
}
.section-title {
  font-family: var(--font-headline);
  font-weight: 700;
  color: var(--color-text-primary);
  font-size: 2.75rem;
  text-align: center;
  margin-bottom: 3rem;
  user-select: none;
}

/* Features Grid */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 2.75rem;
  max-width: 1080px;
  margin-left: auto;
  margin-right: auto;
}
.feature-card {
  background: #ffffff;
  border-radius: var(--border-radius);
  box-shadow: var(--shadow-light);
  padding: 2.5rem 2rem;
  display: flex;
  flex-direction: column;
  transition: box-shadow 0.3s ease, transform 0.3s ease;
  cursor: default;
}
.feature-card:hover,
.feature-card:focus-within {
  box-shadow: var(--shadow-hover);
  transform: translateY(-8px);
  outline: none;
}
.feature-icon {
  font-size: 3rem;
  color: var(--color-btn-bg);
  margin-bottom: 1.25rem;
  line-height: 1;
  user-select: none;
}
.feature-title {
  font-weight: 700;
  font-size: 1.5rem;
  color: var(--color-text-primary);
  margin-bottom: 1rem;
  user-select: none;
}
.feature-desc {
  flex-grow: 1;
  color: var(--color-text-secondary);
  line-height: 1.6;
  font-size: 1.125rem;
}

/* How It Works Section */
.steps-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 3rem;
  max-width: 960px;
  margin-left: auto;
  margin-right: auto;
}
.step-card {
  background: #f9fafb;
  border-radius: var(--border-radius);
  padding: 2rem 2.5rem;
  box-shadow: var(--shadow-light);
  text-align: center;
  transition: box-shadow 0.3s ease, transform 0.3s ease;
  cursor: default;
}
.step-card:hover,
.step-card:focus-within {
  box-shadow: var(--shadow-hover);
  transform: translateY(-6px);
  outline: none;
}
.step-icon {
  font-size: 3rem;
  color: var(--color-btn-bg);
  user-select: none;
  margin-bottom: 1rem;
}
.step-title {
  font-weight: 700;
  font-size: 1.5rem;
  color: var(--color-text-primary);
  margin-bottom: 0.75rem;
  user-select: none;
}
.step-desc {
  font-size: 1.125rem;
  color: var(--color-text-secondary);
  line-height: 1.5;
}

/* Use Cases Section */
.use-cases-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 3rem;
  max-width: 960px;
  margin-left: auto;
  margin-right: auto;
}
.use-case-card {
  background: #ffffff;
  border-radius: var(--border-radius);
  padding: 2rem 2.5rem;
  box-shadow: var(--shadow-light);
  transition: box-shadow 0.3s ease, transform 0.3s ease;
  cursor: default;
}
.use-case-card:hover,
.use-case-card:focus-within {
  box-shadow: var(--shadow-hover);
  transform: translateY(-6px);
  outline: none;
}
.use-case-title {
  font-weight: 700;
  font-size: 1.5rem;
  color: var(--color-text-primary);
  margin-bottom: 1rem;
  user-select: none;
}
.use-case-desc {
  font-size: 1.125rem;
  color: var(--color-text-secondary);
  line-height: 1.5;
}

/* Testimonials Section */
.testimonials-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 3rem;
  max-width: 960px;
  margin-left: auto;
  margin-right: auto;
}
.testimonial {
  border-radius: var(--border-radius);
  background: #f9fafb;
  box-shadow: var(--shadow-light);
  padding: 2rem 2.5rem;
  font-style: italic;
  color: var(--color-text-primary);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: box-shadow 0.3s ease, transform 0.3s ease;
  cursor: default;
}
.testimonial:hover,
.testimonial:focus-within {
  box-shadow: var(--shadow-hover);
  transform: translateY(-6px);
  outline: none;
}
.testimonial p {
  margin-bottom: 1.5rem;
  font-size: 1.125rem;
  line-height: 1.6;
}
.testimonial footer {
  font-style: normal;
  font-weight: 600;
  font-size: 1rem;
  color: var(--color-text-secondary);
  user-select: none;
}

/* Final Call to Action */
.final-cta {
  background-color: #111827;
  color: #ffffff;
  padding-top: var(--spacing-section-vertical);
  padding-bottom: var(--spacing-section-vertical);
  text-align: center;
}
.final-cta-title {
  font-family: var(--font-headline);
  font-weight: 700;
  font-size: 2.75rem;
  margin-bottom: 2rem;
  max-width: 700px;
  margin-left: auto;
  margin-right: auto;
  user-select: none;
}
.final-cta-btn {
  background-color: #fbbf24; /* bright amber for contrast */
  color: #111827;
  font-weight: 700;
  padding: 1.25rem 3rem;
  border-radius: var(--border-radius);
  box-shadow: 0 6px 16px rgb(251 191 36 / 0.4);
  transition: background-color 0.3s ease, transform 0.3s ease, box-shadow 0.3s ease;
  user-select: none;
  display: inline-block;
}
.final-cta-btn:hover,
.final-cta-btn:focus {
  background-color: #d97706;
  box-shadow: 0 10px 30px rgb(217 119 6 / 0.6);
  transform: scale(1.05);
  outline: none;
}

/* Footer */
.site-footer {
  text-align: center;
  padding-top: 3rem;
  padding-bottom: 3rem;
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  user-select: none;
  background: #f9fafb;
  border-top: 1px solid #e5e7eb;
}

/* Responsive adjustments */
@media (max-width: 640px) {
  .hero-title {
    font-size: 2.5rem;
  }
  .hero-subtitle {
    font-size: 1.125rem;
  }
  .nav-links {
    gap: 1rem;
    font-size: 0.95rem;
  }
  .btn-primary, .nav-cta, .hero-cta, .final-cta-btn {
    width: 100%;
    padding-left: 0;
    padding-right: 0;
    text-align: center;
  }
}