:root {
  --bg: #0f172a;
  --bg-surface: #111b35;
  --text: #0f172a;
  --muted: #475569;
  --primary: #2563eb;
  --primary-dark: #1e40af;
  --accent: #22d3ee;
  --font: 'Inter', 'Segoe UI', system-ui, -apple-system, sans-serif;
  --radius: 18px;
  --shadow: 0 18px 45px rgba(15, 23, 42, 0.25);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: var(--font);
  color: var(--text);
  background: #f8fafc;
  line-height: 1.6;
}

img {
  display: block;
  max-width: 100%;
}

a {
  color: inherit;
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

.hero {
  background: radial-gradient(circle at 10% 20%, rgba(37, 99, 235, 0.18), transparent 55%),
              radial-gradient(circle at 90% 0%, rgba(34, 211, 238, 0.2), transparent 45%),
              linear-gradient(135deg, #0f172a, #1e293b);
  color: #e2e8f0;
  padding: 36px clamp(24px, 6vw, 72px) 72px;
  position: relative;
  overflow: hidden;
}

.hero::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(120deg, rgba(255, 255, 255, 0.1), transparent 60%);
  pointer-events: none;
}

.top-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  position: relative;
  z-index: 1;
  margin-bottom: clamp(32px, 5vw, 64px);
}

.logo {
  display: flex;
  align-items: center;
  gap: 12px;
  font-weight: 600;
  font-size: 1.1rem;
}

.nav-link {
  font-weight: 600;
  color: #cbd5f5;
}

.nav-link:hover {
  color: #fff;
}

.hero-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: clamp(32px, 6vw, 64px);
  position: relative;
  z-index: 1;
  align-items: center;
}

.hero-text h1 {
  font-size: clamp(2.4rem, 5vw, 3.6rem);
  line-height: 1.1;
  margin: 12px 0 16px;
}

.hero-text .lead {
  color: rgba(248, 250, 252, 0.85);
  max-width: 520px;
}

.tag {
  text-transform: uppercase;
  letter-spacing: 0.14em;
  font-weight: 600;
  font-size: 0.9rem;
  color: rgba(148, 163, 184, 0.9);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  margin-top: 28px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 22px;
  border-radius: 999px;
  font-weight: 600;
  border: none;
  background: rgba(15, 23, 42, 0.15);
  color: inherit;
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.15s ease, background 0.15s ease;
}

.button.primary {
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  color: #fff;
  box-shadow: 0 12px 30px rgba(37, 99, 235, 0.4);
}

.button.primary:hover {
  transform: translateY(-2px);
}

.button.ghost {
  background: rgba(148, 163, 184, 0.15);
  color: #e2e8f0;
}

.button.small {
  padding: 10px 16px;
  font-size: 0.9rem;
}

.button:disabled {
  cursor: not-allowed;
  opacity: 0.6;
  transform: none;
  box-shadow: none;
}

.hero-demo {
  display: flex;
  justify-content: flex-end;
}

.demo-card {
  background: rgba(15, 23, 42, 0.65);
  border: 1px solid rgba(148, 163, 184, 0.2);
  border-radius: var(--radius);
  padding: 28px;
  max-width: 360px;
  box-shadow: var(--shadow);
  backdrop-filter: blur(12px);
}

.demo-title {
  margin: 0 0 12px;
  font-weight: 600;
  font-size: 1.1rem;
}

.demo-label {
  display: block;
  font-size: 0.9rem;
  margin: 16px 0 6px;
  color: rgba(203, 213, 225, 0.88);
}

.demo-select,
.demo-text {
  width: 100%;
  border-radius: 12px;
  border: 1px solid rgba(148, 163, 184, 0.3);
  padding: 12px;
  font-size: 1rem;
  background: rgba(15, 23, 42, 0.3);
  color: #e2e8f0;
}

.demo-text {
  resize: vertical;
}

.demo-actions {
  display: flex;
  gap: 12px;
  margin-top: 18px;
}

.demo-note {
  font-size: 0.85rem;
  color: rgba(203, 213, 225, 0.7);
  margin-top: 14px;
}

main {
  padding: clamp(48px, 6vw, 96px) clamp(24px, 8vw, 120px) 120px;
}

.section {
  margin-bottom: clamp(64px, 8vw, 120px);
}

.section h2 {
  font-size: clamp(2rem, 4vw, 2.8rem);
  margin-bottom: 32px;
  text-align: center;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 24px;
}

.feature-card {
  background: #fff;
  border-radius: var(--radius);
  padding: 28px;
  box-shadow: 0 16px 40px rgba(15, 23, 42, 0.08);
}

.feature-card h3 {
  margin-top: 0;
  margin-bottom: 12px;
}

.install {
  text-align: center;
}

.install-grid {
  margin-top: 32px;
  display: grid;
  gap: 32px;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
}

.install-card {
  background: linear-gradient(160deg, #ffffff 0%, #f1f5f9 100%);
  border-radius: var(--radius);
  padding: 32px;
  box-shadow: 0 18px 40px rgba(15, 23, 42, 0.08);
  text-align: left;
}

.install-card h3 {
  margin-top: 0;
}

.install-steps {
  margin: 16px 0 24px 20px;
  padding: 0;
  color: var(--muted);
}

.install-steps li {
  margin-bottom: 12px;
}

.install-card .button {
  width: 100%;
}

.surface {
  background: #0f172a;
  color: #e2e8f0;
  border-radius: calc(var(--radius) * 1.6);
  padding: clamp(48px, 5vw, 72px);
}

.use-grid {
  display: grid;
  gap: 24px;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

.use-card {
  background: rgba(15, 23, 42, 0.35);
  border-radius: var(--radius);
  padding: 24px;
  border: 1px solid rgba(148, 163, 184, 0.2);
}

.faq-list {
  display: grid;
  gap: 24px;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
}

.faq-item {
  background: #fff;
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: 0 16px 35px rgba(15, 23, 42, 0.08);
}

.footer {
  text-align: center;
  padding: 48px 24px;
  background: #0f172a;
  color: #94a3b8;
}

.footer p {
  margin: 0;
}

@media (max-width: 720px) {
  .hero {
    padding-bottom: 56px;
  }

  .hero-demo {
    justify-content: center;
  }

  .install-card {
    text-align: left;
  }

  .hero-actions {
    flex-direction: column;
    align-items: stretch;
  }

  .button {
    width: 100%;
  }
}