:root {
  --bg: #0b1220;
  --surface: #ffffff;
  --text: #0f172a;
  --muted: #64748b;
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --accent: #0ea5e9;
  --border: #e2e8f0;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: "Inter", system-ui, -apple-system, Segoe UI, Roboto, sans-serif;
  color: var(--text);
  background: #f8fafc;
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 18px 32px;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 10;
}
.brand { font-weight: 700; font-size: 20px; display: flex; align-items: center; gap: 8px; }
.brand .logo { font-size: 24px; }
.nav-links { display: flex; align-items: center; gap: 22px; }
.nav-links a { text-decoration: none; color: var(--muted); font-size: 14px; }
.nav-links a:hover { color: var(--text); }

.btn {
  display: inline-block;
  padding: 10px 18px;
  border-radius: 10px;
  font-size: 14px;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  transition: transform 0.05s ease, background 0.15s ease;
}
.btn:active { transform: translateY(1px); }
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-dark); }
.btn-outline { border: 1px solid var(--primary); color: var(--primary) !important; }
.btn-outline:hover { background: var(--primary); color: #fff !important; }
.btn-ghost { color: var(--primary) !important; }

.hero {
  max-width: 860px;
  margin: 0 auto;
  padding: 88px 24px 56px;
  text-align: center;
}
.hero h1 { font-size: 46px; line-height: 1.1; margin: 0 0 20px; letter-spacing: -0.02em; }
.hero .sub { font-size: 19px; color: var(--muted); max-width: 660px; margin: 0 auto 28px; }
.cta-row { display: flex; gap: 14px; justify-content: center; align-items: center; }
.hint { margin-top: 22px; color: var(--muted); font-size: 14px; }

code {
  background: #eef2ff;
  color: #3730a3;
  padding: 2px 7px;
  border-radius: 6px;
  font-size: 0.9em;
}

.features {
  max-width: 1080px;
  margin: 0 auto;
  padding: 24px 24px 64px;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 20px;
}
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 24px;
  box-shadow: 0 8px 24px rgba(15, 23, 42, 0.05);
}
.card h3 { margin: 0 0 8px; font-size: 17px; }
.card p { margin: 0; color: var(--muted); font-size: 14px; line-height: 1.5; }

.how, .contact {
  max-width: 780px;
  margin: 0 auto;
  padding: 48px 24px;
  text-align: center;
}
.how { text-align: left; }
.how h2, .contact h2 { font-size: 28px; margin-bottom: 18px; }
.how ol { font-size: 16px; color: var(--text); line-height: 1.9; padding-left: 20px; }
.contact p { color: var(--muted); font-size: 16px; margin-bottom: 22px; }

.footer {
  border-top: 1px solid var(--border);
  padding: 22px 32px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: var(--muted);
  font-size: 14px;
  background: var(--surface);
}
.footer a { color: var(--primary); text-decoration: none; }

@media (max-width: 640px) {
  .hero h1 { font-size: 34px; }
  .nav-links a:not(.btn) { display: none; }
}