:root {
  --brand: #2b4eff;
  --brand-dark: #1a35cc;
  --ink: #14161f;
  --ink-soft: #565c72;
  --bg: #ffffff;
  --bg-soft: #f5f6fb;
  --border: #e4e6f0;
  --radius: 14px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.5;
}

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

h1, h2, h3 {
  line-height: 1.2;
  margin: 0 0 12px;
}

/* --- Nav --- */

.nav {
  position: sticky;
  top: 0;
  z-index: 20;
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}

.nav-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 14px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 18px;
}

.brand img {
  width: 32px;
  height: 32px;
  border-radius: 8px;
  object-fit: cover;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 28px;
  font-weight: 500;
  color: var(--ink-soft);
}

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

.nav-cta {
  background: var(--brand);
  color: #fff !important;
  padding: 9px 18px;
  border-radius: 999px;
  font-weight: 600;
}

.nav-cta:hover {
  background: var(--brand-dark);
}

/* --- Hero --- */

.hero {
  padding: 96px 24px 72px;
  background: radial-gradient(circle at 20% -10%, #eef1ff 0%, #ffffff 55%);
}

.hero-inner {
  max-width: 780px;
  margin: 0 auto;
  text-align: center;
}

.hero h1 {
  font-size: clamp(32px, 5vw, 52px);
  font-weight: 800;
  letter-spacing: -0.02em;
}

.hero-sub {
  font-size: 18px;
  color: var(--ink-soft);
  max-width: 620px;
  margin: 0 auto 32px;
}

.hero-cta {
  display: flex;
  justify-content: center;
  gap: 14px;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 26px;
  border-radius: 12px;
  font-weight: 700;
  font-size: 15px;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform 0.15s ease, background 0.15s ease;
}

.btn:hover {
  transform: translateY(-1px);
}

.btn-primary {
  background: var(--brand);
  color: #fff;
}

.btn-primary:hover {
  background: var(--brand-dark);
}

.btn-ghost {
  background: #fff;
  border-color: var(--border);
  color: var(--ink);
}

.btn-block {
  width: 100%;
}

.btn[disabled] {
  opacity: 0.6;
  cursor: not-allowed;
  transform: none;
}

/* --- Features --- */

.features {
  max-width: 1100px;
  margin: 0 auto;
  padding: 24px 24px 96px;
}

.features h2,
.audience h2,
.signup h2 {
  text-align: center;
  font-size: clamp(24px, 3vw, 32px);
  font-weight: 800;
  margin-bottom: 40px;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 20px;
}

.feature-card {
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 26px;
}

.feature-icon {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 16px;
}

.feature-icon svg {
  width: 20px;
  height: 20px;
}

.icon-blue {
  background: rgba(37, 99, 235, 0.12);
  color: #2563eb;
}

.icon-green {
  background: rgba(22, 163, 74, 0.12);
  color: #16a34a;
}

.icon-purple {
  background: rgba(124, 58, 237, 0.12);
  color: #7c3aed;
}

.icon-orange {
  background: rgba(217, 119, 6, 0.12);
  color: #d97706;
}

.icon-teal {
  background: rgba(8, 145, 178, 0.12);
  color: #0891b2;
}

.icon-red {
  background: rgba(220, 38, 38, 0.12);
  color: #dc2626;
}

.feature-card h3 {
  font-size: 17px;
}

.feature-card p {
  color: var(--ink-soft);
  margin: 0;
  font-size: 14.5px;
}

/* --- Audience --- */

.audience {
  background: var(--bg-soft);
  padding: 72px 24px;
}

.audience-list {
  max-width: 640px;
  margin: 0 auto;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 14px;
}

.audience-list li {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 16px 20px;
  font-weight: 600;
}

.audience-list li::before {
  content: "✓ ";
  color: var(--brand);
}

/* --- Signup --- */

.signup {
  padding: 96px 24px;
}

.signup-card {
  max-width: 460px;
  margin: 0 auto;
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 36px;
}

.signup-sub {
  text-align: center;
  color: var(--ink-soft);
  margin-top: -20px;
  margin-bottom: 28px;
}

#signup-form {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

#signup-form label {
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-size: 14px;
  font-weight: 600;
  color: var(--ink-soft);
}

#signup-form input {
  font: inherit;
  padding: 12px 14px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: #fff;
  color: var(--ink);
}

#signup-form input:focus {
  outline: 2px solid var(--brand);
  outline-offset: 1px;
}

.signup-message {
  text-align: center;
  font-weight: 600;
  padding: 12px;
  border-radius: 10px;
  margin: 0;
}

.signup-message.success {
  background: #e7f7ee;
  color: #16a34a;
}

.signup-message.error {
  background: #fdeceb;
  color: #dc2626;
}

/* --- Footer --- */

.footer {
  text-align: center;
  padding: 28px 24px 40px;
  color: var(--ink-soft);
  font-size: 13px;
}

/* --- Responsive --- */

@media (max-width: 768px) {
  .hero {
    padding: 56px 20px 44px;
  }

  .features {
    padding: 8px 20px 64px;
  }

  .audience,
  .signup {
    padding: 56px 20px;
  }

  .feature-grid {
    grid-template-columns: repeat(auto-fit, minmax(min(260px, 100%), 1fr));
  }

  .features h2,
  .audience h2,
  .signup h2 {
    margin-bottom: 24px;
  }
}

@media (max-width: 560px) {
  .nav-inner {
    padding: 12px 16px;
  }

  .brand {
    font-size: 18px;
    gap: 8px;
  }

  .brand img {
    width: 30px;
    height: 30px;
  }

  .nav-links {
    gap: 10px;
  }

  .nav-links a:not(.nav-cta) {
    display: none;
  }

  .nav-cta {
    padding: 8px 16px;
    font-size: 14px;
  }

  .hero-sub {
    font-size: 16px;
  }

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

  .signup-card {
    padding: 22px;
  }

  .signup-sub {
    margin-top: -8px;
  }

  .audience-list li {
    padding: 14px 16px;
    font-size: 14.5px;
  }
}