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

:root {
  --black: #111;
  --dark: #333;
  --mid: #666;
  --light: #999;
  --subtle: #e5e5e5;
  --bg-card: #f5f5f5;
  --white: #fff;
  --radius: 8px;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--dark);
  line-height: 1.6;
  background: var(--white);
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ---- Header ---- */

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--subtle);
  z-index: 100;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.logo-link {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--black);
}

.logo-img {
  width: 36px;
  height: 36px;
}

.logo-text {
  font-size: 1.125rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.header-nav {
  display: flex;
  align-items: center;
  gap: 32px;
}

.header-nav a {
  text-decoration: none;
  color: var(--mid);
  font-size: 0.875rem;
  font-weight: 500;
  transition: color 0.2s;
}

.header-nav a:hover {
  color: var(--black);
}

.nav-cta {
  background: var(--black);
  color: var(--white) !important;
  padding: 8px 20px;
  border-radius: var(--radius);
  transition: background 0.2s !important;
}

.nav-cta:hover {
  background: var(--dark) !important;
}

/* ---- Hero ---- */

.hero {
  text-align: center;
  padding: 160px 24px 100px;
}

.hero-logo {
  width: 80px;
  height: 80px;
  margin-bottom: 32px;
}

.hero h1 {
  font-size: clamp(2.25rem, 5vw, 3.5rem);
  font-weight: 800;
  color: var(--black);
  letter-spacing: -0.03em;
  line-height: 1.15;
  margin-bottom: 20px;
}

.hero-sub {
  font-size: 1.125rem;
  color: var(--mid);
  max-width: 560px;
  margin: 0 auto 40px;
  line-height: 1.7;
}

.btn {
  display: inline-block;
  background: var(--black);
  color: var(--white);
  text-decoration: none;
  font-size: 1rem;
  font-weight: 600;
  padding: 14px 36px;
  border-radius: var(--radius);
  transition: background 0.2s;
}

.btn:hover {
  background: var(--dark);
}

/* ---- Sections ---- */

section {
  padding: 100px 0;
}

section h2 {
  font-size: 2rem;
  font-weight: 800;
  color: var(--black);
  text-align: center;
  letter-spacing: -0.02em;
  margin-bottom: 12px;
}

.section-sub {
  text-align: center;
  color: var(--mid);
  font-size: 1.0625rem;
  max-width: 520px;
  margin: 0 auto 56px;
}

/* ---- Features ---- */

.features {
  background: var(--bg-card);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.feature-card {
  background: var(--white);
  border: 1px solid var(--subtle);
  border-radius: var(--radius);
  padding: 32px 28px;
}

.feature-icon {
  font-size: 1.5rem;
  margin-bottom: 16px;
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-card);
  border-radius: var(--radius);
}

.feature-card h3 {
  font-size: 1.0625rem;
  font-weight: 700;
  color: var(--black);
  margin-bottom: 8px;
}

.feature-card p {
  font-size: 0.9375rem;
  color: var(--mid);
  line-height: 1.6;
}

/* ---- Platform ---- */

.platform-split {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
}

.platform-card {
  border: 1px solid var(--subtle);
  border-radius: var(--radius);
  padding: 40px 36px;
}

.platform-label {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--light);
  margin-bottom: 12px;
}

.platform-card h3 {
  font-size: 1.375rem;
  font-weight: 800;
  color: var(--black);
  margin-bottom: 20px;
}

.platform-card ul {
  list-style: none;
}

.platform-card li {
  position: relative;
  padding-left: 20px;
  margin-bottom: 12px;
  font-size: 0.9375rem;
  color: var(--dark);
  line-height: 1.5;
}

.platform-card li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 8px;
  width: 6px;
  height: 6px;
  background: var(--black);
  border-radius: 50%;
}

/* ---- How It Works ---- */

.how-it-works {
  background: var(--bg-card);
}

.steps {
  display: flex;
  align-items: flex-start;
  justify-content: center;
  gap: 0;
}

.step {
  flex: 1;
  max-width: 280px;
  text-align: center;
  padding: 0 24px;
}

.step-number {
  width: 48px;
  height: 48px;
  border: 2px solid var(--black);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--black);
  margin: 0 auto 20px;
}

.step h3 {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--black);
  margin-bottom: 8px;
}

.step p {
  font-size: 0.9375rem;
  color: var(--mid);
  line-height: 1.6;
}

.step-divider {
  width: 60px;
  height: 2px;
  background: var(--subtle);
  margin-top: 24px;
  flex-shrink: 0;
}

/* ---- Contact ---- */

.contact {
  text-align: center;
  padding: 100px 0 120px;
}

.contact .btn {
  margin-bottom: 16px;
}

.contact-note {
  font-size: 0.875rem;
  color: var(--light);
}

/* ---- Footer ---- */

.site-footer {
  border-top: 1px solid var(--subtle);
  padding: 40px 0;
}

.footer-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 700;
  font-size: 1rem;
  color: var(--black);
}

.footer-logo {
  width: 28px;
  height: 28px;
}

.footer-byline {
  font-size: 0.875rem;
  color: var(--mid);
}

.footer-byline a {
  color: var(--dark);
  text-decoration: underline;
  text-underline-offset: 2px;
}

.footer-byline a:hover {
  color: var(--black);
}

.footer-copy {
  font-size: 0.8125rem;
  color: var(--light);
}

/* ---- Responsive ---- */

@media (max-width: 768px) {
  .header-nav a:not(.nav-cta) {
    display: none;
  }

  .hero {
    padding: 120px 24px 72px;
  }

  .hero-logo {
    width: 64px;
    height: 64px;
  }

  section {
    padding: 72px 0;
  }

  .features-grid {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  .platform-split {
    grid-template-columns: 1fr;
    gap: 20px;
  }

  .platform-card {
    padding: 28px 24px;
  }

  .steps {
    flex-direction: column;
    align-items: center;
    gap: 40px;
  }

  .step-divider {
    width: 2px;
    height: 40px;
    margin: 0;
  }

  .contact {
    padding: 72px 0 88px;
  }
}

@media (max-width: 480px) {
  .header-inner {
    height: 56px;
  }

  .hero {
    padding: 100px 20px 56px;
  }

  .hero h1 {
    font-size: 1.875rem;
  }

  .hero-sub {
    font-size: 1rem;
  }

  section h2 {
    font-size: 1.625rem;
  }
}