@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}
.body {
  background-color: #1a202c;
  color: white;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen,
    Ubuntu, Cantarell, "Open Sans", "Helvetica Neue", sans-serif;
  margin: 0;
}

/* Hero Section */
.hero-section {
  text-align: center;
  padding: 5rem 1rem;
}

.hero-logo {
  margin: 0 auto 1.5rem auto;
  width: 15rem; /* 60 * 0.25rem */
  display: block;
}

.hero-title {
  font-size: 2.25rem; /* 4xl */
  font-weight: 700;
  margin-bottom: 1rem;
}

@media (min-width: 768px) {
  .hero-title {
    font-size: 3.75rem; /* 6xl */
  }
}

.hero-subtitle {
  font-size: 1.125rem; /* lg */
  max-width: 40rem; /* max-w-2xl */
  margin: 0 auto 2rem auto;
}

@media (min-width: 768px) {
  .hero-subtitle {
    font-size: 1.25rem; /* xl */
  }
}

.btn-invite {
  background-color: #3b82f6; /* blue-500 */
  color: white;
  font-weight: 600;
  padding: 0.75rem 1.5rem;
  border-radius: 1rem;
  text-decoration: none;
  transition: background-color 0.3s ease;
  display: inline-block;
}

.btn-invite:hover {
  background-color: #2563eb; /* blue-600 */
}

/* Features Section */
.features-section {
  background-color: #2d3748; /* bg-gray-800 */
  padding: 4rem 1.5rem;
}

.features-grid {
  max-width: 80rem; /* max-w-5xl */
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(1, 1fr);
  gap: 2rem;
  text-align: center;
}

@media (min-width: 768px) {
  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .features-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.feature-item h3 {
  font-size: 1.25rem; /* xl */
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.feature-item-full {
  grid-column: span 3;
  display: flex;
  justify-content: center;
}

.feature-item-full > div {
  text-align: center;
}

/* Why Free Section */
.why-free-section {
  text-align: center;
  padding: 5rem 1.5rem;
}

.why-free-section h2 {
  font-size: 1.875rem; /* 3xl */
  font-weight: 700;
  margin-bottom: 1.5rem;
}

.why-free-text {
  max-width: 42rem; /* max-w-xl */
  margin: 0 auto 1.5rem auto;
}

.link {
  color: #60a5fa; /* blue-400 */
  text-decoration: underline;
  margin: 0 0.5rem;
}

/* Footer */
.footer {
  background-color: #2d3748; /* bg-gray-800 */
  text-align: center;
  padding: 1.5rem 0;
  font-size: 0.875rem; /* text-sm */
}
a {
  color: #00ccff;
  text-decoration: none;
}