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

body {
  margin: 0;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: #f5f7ff;
  background-color: #050816;
}

.bg-video-wrap {
  position: fixed;
  inset: 0;
  overflow: hidden;
  z-index: -2;
}

.bg-video-wrap video {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.overlay-gradient {
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at top, rgba(94, 234, 212, 0.35), transparent 55%),
              radial-gradient(circle at bottom, rgba(59, 130, 246, 0.35), transparent 55%),
              rgba(5, 8, 22, 0.95);
  z-index: -1;
}

.site-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1.25rem 8vw;
  position: sticky;
  top: 0;
  z-index: 10;
  backdrop-filter: blur(16px);
  background: linear-gradient(to bottom, rgba(5, 8, 22, 0.9), transparent);
}

.logo {
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  font-size: 0.9rem;
  color: #a5b4fc;
}

.nav a {
  margin-left: 1.5rem;
  text-decoration: none;
  color: #e5e7eb;
  font-size: 0.9rem;
  opacity: 0.8;
}

.nav a:hover {
  opacity: 1;
}

.hero {
  padding: 7rem 8vw 5rem;
  max-width: 720px;
}

.hero h1 {
  font-size: clamp(2.5rem, 5vw, 3.7rem);
  margin-bottom: 0.75rem;
}

.hero h2 {
  font-size: clamp(1.25rem, 2.5vw, 1.75rem);
  font-weight: 400;
  opacity: 0.9;
  margin-bottom: 1.5rem;
}

.hero p {
  max-width: 540px;
  opacity: 0.85;
  margin-bottom: 2rem;
}

.section {
  padding: 3.5rem 8vw;
  max-width: 1024px;
}

.section h2 {
  font-size: 1.75rem;
  margin-bottom: 1rem;
}

.section p {
  line-height: 1.7;
  opacity: 0.9;
}

ul {
  padding-left: 1.1rem;
}

.section-cards .card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.75rem;
  margin-top: 1.75rem;
}

.card {
  background: rgba(15, 23, 42, 0.9);
  border-radius: 1.25rem;
  padding: 1.5rem;
  border: 1px solid rgba(148, 163, 184, 0.3);
  box-shadow: 0 18px 40px rgba(15, 23, 42, 0.7);
}

.card h3 {
  margin-top: 0;
  margin-bottom: 0.75rem;
}

.section-join {
  background: radial-gradient(circle at top left, rgba(56, 189, 248, 0.25), transparent 55%),
              radial-gradient(circle at bottom right, rgba(139, 92, 246, 0.25), transparent 55%),
              rgba(15, 23, 42, 0.9);
  border-radius: 2rem;
  margin: 3rem 8vw;
  padding: 3rem 2rem;
  max-width: 960px;
}

.section-join ul {
  columns: 2;
  column-gap: 2rem;
  margin-bottom: 1.5rem;
}

.signup-form {
  margin-top: 1rem;
}

.form-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 0.5rem;
}

.signup-form input[type="email"] {
  flex: 1 1 220px;
  padding: 0.75rem 0.9rem;
  border-radius: 999px;
  border: 1px solid rgba(148, 163, 184, 0.5);
  background: rgba(15, 23, 42, 0.9);
  color: #e5e7eb;
}

.signup-form input::placeholder {
  color: #9ca3af;
}

.form-note {
  font-size: 0.8rem;
  opacity: 0.8;
  margin-top: 0.5rem;
}

.form-success {
  margin-top: 0.75rem;
  font-size: 0.9rem;
  color: #a7f3d0;
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.75rem 1.4rem;
  border-radius: 999px;
  border: none;
  cursor: pointer;
  font-weight: 600;
  font-size: 0.95rem;
  text-decoration: none;
  background: linear-gradient(135deg, #38bdf8, #6366f1);
  color: #0b1120;
  box-shadow: 0 12px 28px rgba(37, 99, 235, 0.4);
  transform: translateY(0);
  transition: transform 0.12s ease, box-shadow 0.12s ease, filter 0.12s ease;
}

.btn-primary:hover {
  transform: translateY(-1px);
  box-shadow: 0 16px 32px rgba(37, 99, 235, 0.5);
  filter: brightness(1.05);
}

.site-footer {
  padding: 2.5rem 8vw 2rem;
  font-size: 0.9rem;
  opacity: 0.8;
}

.footer-small {
  font-size: 0.75rem;
  opacity: 0.7;
}

@media (max-width: 768px) {
  .site-header {
    padding-inline: 6vw;
  }

  .hero {
    padding-inline: 6vw;
  }

  .section {
    padding-inline: 6vw;
  }

  .section-join {
    margin-inline: 4vw;
    padding-inline: 1.5rem;
  }

  .section-join ul {
    columns: 1;
  }
}