:root {
  --bg: #ffffff;
  --fg: #111;
  --subtle: #555;
  --accent: #007aff;
  --radius: 18px;
  --max-width: 900px;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", system-ui, sans-serif;
  background: var(--bg);
  color: var(--fg);
  line-height: 1.6;
}

/* NAVBAR */
.app-navbar {
  position: sticky;
  top: 0;
  width: 100%;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid #eee;
  z-index: 1000;
  transition: padding 0.25s ease, background 0.25s ease;
  padding: 1rem 0;
}

.app-navbar.shrink {
  padding: 0.4rem 0;
  background: rgba(255, 255, 255, 0.95);
}

.nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--fg);
  text-decoration: none;
}

.nav-links {
  list-style: none;
  display: flex;
  gap: 1.5rem;
  margin: 0;
  padding: 0;
}

.nav-links a {
  text-decoration: none;
  color: var(--fg);
  font-weight: 500;
  transition: color 0.2s ease;
}

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

.nav-links a.active {
  color: #007aff; /* iOS blue */
  font-weight: 600;
}

/* MOBILE */
.nav-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 1.6rem;
  cursor: pointer;
}

@media (max-width: 700px) {
  .nav-toggle {
    display: block;
  }

  .nav-links {
    position: absolute;
    top: 100%;
    right: 0;
    background: white;
    border-left: 1px solid #eee;
    border-bottom: 1px solid #eee;
    width: 200px;
    flex-direction: column;
    padding: 1rem;
    display: none;
  }

  .nav-links.open {
    display: flex;
  }
}


/* HERO */
.hero {
  padding: 5rem 1.5rem 4rem;
  text-align: center;
  background: linear-gradient(180deg, #f5f7ff, #ffffff);
}

.hero h1 {
  font-size: 3rem;
  margin-bottom: 0.5rem;
  font-weight: 700;
}

.hero p {
  font-size: 1.25rem;
  color: var(--subtle);
  max-width: 600px;
  margin: 0.5rem auto 2rem;
}

.cta {
  display: inline-block;
  padding: 0.9rem 2rem;
  background: var(--accent);
  color: white;
  border-radius: var(--radius);
  font-weight: 600;
  text-decoration: none;
  font-size: 1.1rem;
}

/* FEATURE SECTIONS */
.section {
  max-width: var(--max-width);
  margin: 4rem auto;
  padding: 0 1.5rem;
}

.section h2 {
  font-size: 2rem;
  margin-bottom: 1rem;
  text-align: center;
}

.feature-grid {
  display: grid;
  gap: 2rem;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  margin-top: 2rem;
}

.feature {
  background: #fafafa;
  padding: 1.5rem;
  border-radius: var(--radius);
  border: 1px solid #eee;
  text-align: center;
}

.feature h3 {
  margin-top: 0.5rem;
  font-size: 1.25rem;
}

.feature p {
  color: var(--subtle);
  font-size: 0.95rem;
}

/* FOOTER */
footer {
  text-align: center;
  padding: 3rem 1rem;
  color: #777;
  font-size: 0.9rem;
}