/* GraphHelix Marketing Landing Page — Canvas Visual Language */

*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --primary: #0D9488;
  --primary-hover: #0F766E;
  --primary-wash: #F0FDFA;
  --coral: #F97066;
  --foreground: #1E293B;
  --text-secondary: #475569;
  --muted: #94A3B8;
  --border: #E2E8F0;
  --bg: #ffffff;
  --bg-subtle: #F8FAFB;
  --radius-sm: 0.5rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'DM Sans', system-ui, -apple-system, sans-serif;
  color: var(--foreground);
  background: var(--bg);
  font-size: 15px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

/* ── Layout ────────────────────────────────── */

.container {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* ── Navigation ────────────────────────────── */

.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}

.nav .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 3.5rem;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 0.625rem;
  text-decoration: none;
  color: var(--foreground);
  font-weight: 700;
  font-size: 1.0625rem;
  letter-spacing: -0.02em;
}

.nav-brand-mark {
  width: 28px;
  height: 28px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, #0D9488, #14B8A6);
  border-radius: 8px;
}

.nav-brand-mark svg {
  color: white;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 2rem;
  list-style: none;
}

.nav-links a {
  text-decoration: none;
  color: var(--muted);
  font-size: 0.875rem;
  font-weight: 500;
  transition: color 0.15s;
}

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

/* ── Hamburger Menu ───────────────────────── */

.nav-hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 4px;
  width: 2rem;
  height: 2rem;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.25rem;
}

.hamburger-line {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--foreground);
  border-radius: 1px;
  transition: all 0.2s;
}

.nav-mobile-cta {
  display: none !important;
  font-size: 0.75rem;
  padding: 0.5rem 1rem;
}

/* ── Buttons ───────────────────────────────── */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  font-family: inherit;
  font-weight: 600;
  font-size: 0.875rem;
  border: none;
  cursor: pointer;
  text-decoration: none;
  transition: all 0.15s;
  border-radius: var(--radius-lg);
}

.btn-primary {
  background: var(--primary);
  color: #fff !important;
  padding: 0.625rem 1.5rem;
  box-shadow: 0 1px 3px rgba(13, 148, 136, 0.15);
}

.btn-primary:hover {
  background: var(--primary-hover);
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(13, 148, 136, 0.2);
}

.btn-lg {
  font-size: 1rem;
  padding: 0.875rem 2rem;
  border-radius: 2rem;
}

.btn-outline {
  background: transparent;
  color: var(--primary);
  border: 1.5px solid var(--primary);
  padding: 0.625rem 1.5rem;
}

.btn-outline:hover {
  background: var(--primary-wash);
}

/* ── Hero ──────────────────────────────────── */

.hero {
  padding: 8rem 0 5rem;
  text-align: center;
}

.hero-badge {
  display: inline-block;
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--primary);
  background: var(--primary-wash);
  padding: 0.3rem 1rem;
  border-radius: 9999px;
  margin-bottom: 1.5rem;
  border: 1px solid rgba(13, 148, 136, 0.15);
}

.hero h1 {
  font-size: 3.25rem;
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.03em;
  max-width: 720px;
  margin: 0 auto 1.25rem;
}

.hero h1 .highlight {
  background: linear-gradient(135deg, #0D9488, #14B8A6);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero p {
  font-size: 1.125rem;
  color: var(--text-secondary);
  max-width: 560px;
  margin: 0 auto 2rem;
  line-height: 1.7;
}

.hero-sub {
  font-size: 1.125rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto 1rem;
  line-height: 1.7;
}

.hero-persona {
  font-size: 1rem;
  color: var(--text-secondary);
  font-weight: 500;
  margin: 0 auto 2rem;
}

.hero-actions {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.75rem;
}

/* ── AI Section ────────────────────────────── */

.ai-section {
  padding: 5rem 0;
}

.ai-details {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
  margin-top: 2.5rem;
}

.ai-detail {
  background: var(--bg-subtle);
  border: 1px solid var(--border);
  border-radius: 0.75rem;
  padding: 1.75rem;
}

.ai-detail h3 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.ai-detail p {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

.ai-detail em {
  font-style: italic;
}

/* ── Features ──────────────────────────────── */

.features {
  padding: 5rem 0;
  background: var(--bg-subtle);
}

.section-label {
  display: block;
  font-size: 0.8125rem;
  font-weight: 700;
  color: var(--primary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.5rem;
  text-align: center;
}

.section-title {
  font-size: 2rem;
  font-weight: 700;
  text-align: center;
  margin-bottom: 0.75rem;
  letter-spacing: -0.03em;
}

.section-subtitle {
  font-size: 1rem;
  color: var(--text-secondary);
  text-align: center;
  max-width: 520px;
  margin: 0 auto 3rem;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}

.feature-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 0.75rem;
  padding: 1.75rem;
  transition: all 0.2s;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.04);
}

.feature-card:hover {
  box-shadow: 0 4px 16px rgba(13, 148, 136, 0.08);
  border-color: rgba(13, 148, 136, 0.3);
  transform: translateY(-2px);
}

.feature-icon {
  width: 2.5rem;
  height: 2.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--primary-wash);
  color: var(--primary);
  border-radius: 10px;
  margin-bottom: 1rem;
}

.feature-card h3 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 0.375rem;
}

.feature-card p {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ── Tests Section ────────────────────────── */

.tests-section {
  padding: 5rem 0;
}

.tests-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
  margin-bottom: 2rem;
}

.test-group {
  background: var(--bg-subtle);
  border: 1px solid var(--border);
  border-radius: 0.75rem;
  padding: 1.5rem;
}

.test-group h3 {
  font-size: 0.9375rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
  color: var(--foreground);
}

.test-group ul {
  list-style: none;
  padding: 0;
}

.test-group li {
  font-size: 0.8125rem;
  color: var(--text-secondary);
  padding: 0.25rem 0;
  line-height: 1.5;
}

.tests-callout {
  background: var(--primary-wash);
  border: 1px solid rgba(13, 148, 136, 0.15);
  border-radius: 0.75rem;
  padding: 1.5rem;
  text-align: center;
}

.tests-callout p {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

.tests-custom {
  margin-top: 0.5rem;
  font-size: 0.8125rem !important;
  color: var(--muted) !important;
}

/* ── Transparency ─────────────────────────── */

.transparency {
  padding: 5rem 0;
  background: var(--bg-subtle);
}

.transparency-steps {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.5rem;
  margin-bottom: 2.5rem;
}

.t-step {
  text-align: center;
}

.t-step-number {
  width: 2.5rem;
  height: 2.5rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  font-weight: 700;
  color: white;
  background: linear-gradient(135deg, #0D9488, #14B8A6);
  border-radius: 50%;
  margin-bottom: 1rem;
  box-shadow: 0 2px 8px rgba(13, 148, 136, 0.2);
}

.t-step h3 {
  font-size: 0.9375rem;
  font-weight: 700;
  margin-bottom: 0.375rem;
}

.t-step p {
  font-size: 0.8125rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

.transparency-note {
  background: var(--bg);
  border: 2px solid var(--coral);
  border-radius: 0.75rem;
  padding: 1.5rem;
  text-align: center;
}

.transparency-note p {
  font-size: 0.875rem;
  color: var(--foreground);
  line-height: 1.7;
}

/* ── How It Works ──────────────────────────── */

.how-it-works {
  padding: 5rem 0;
}

.steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
  position: relative;
}

.steps::before {
  content: '';
  position: absolute;
  top: 1.5rem;
  left: calc(16.67% + 2rem);
  right: calc(16.67% + 2rem);
  height: 2px;
  background: var(--border);
  z-index: 0;
}

.step {
  text-align: center;
  position: relative;
}

.step-number {
  width: 3rem;
  height: 3rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 1.125rem;
  font-weight: 700;
  color: white;
  background: linear-gradient(135deg, #0D9488, #14B8A6);
  border-radius: 50%;
  margin-bottom: 1.25rem;
  position: relative;
  z-index: 1;
  box-shadow: 0 2px 8px rgba(13, 148, 136, 0.2);
}

.step h3 {
  font-size: 1.125rem;
  font-weight: 700;
  margin-bottom: 0.375rem;
}

.step p {
  font-size: 0.875rem;
  color: var(--text-secondary);
  max-width: 280px;
  margin: 0 auto;
  line-height: 1.6;
}

/* ── Data & Privacy ────────────────────────── */

.data-privacy {
  padding: 5rem 0;
}

.data-privacy h2 {
  font-size: 2rem;
  font-weight: 700;
  text-align: center;
  margin-bottom: 2.5rem;
  letter-spacing: -0.03em;
}

.privacy-points {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
  margin-bottom: 1.5rem;
}

.privacy-point {
  text-align: center;
}

.privacy-point h3 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 0.375rem;
}

.privacy-point p {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

.privacy-note {
  font-size: 0.8125rem;
  color: var(--muted);
  text-align: center;
}

/* ── CTA Footer ────────────────────────────── */

.cta-section {
  padding: 5rem 0;
  background: linear-gradient(135deg, #0D9488, #14B8A6, #2DD4BF);
  text-align: center;
  color: white;
  position: relative;
  overflow: hidden;
}

.cta-section::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -20%;
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, rgba(255,255,255,0.1), transparent 70%);
  border-radius: 50%;
}

.cta-section h2 {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
  letter-spacing: -0.03em;
  position: relative;
}

.cta-section p {
  font-size: 1rem;
  opacity: 0.85;
  margin-bottom: 2rem;
  max-width: 480px;
  margin-left: auto;
  margin-right: auto;
  position: relative;
}

.cta-section .btn-primary {
  background: white;
  color: var(--primary) !important;
  box-shadow: 0 4px 16px rgba(0,0,0,0.1);
}

.cta-section .btn-primary:hover {
  background: white;
  transform: translateY(-2px);
  box-shadow: 0 6px 24px rgba(0,0,0,0.15);
}

.cta-section .waitlist-form input[type="email"] {
  border-color: rgba(255,255,255,0.3);
  background: rgba(255,255,255,0.15);
  color: white;
}

.cta-section .waitlist-form input[type="email"]::placeholder {
  color: rgba(255,255,255,0.6);
}

.cta-section .waitlist-form input[type="email"]:focus {
  border-color: white;
  box-shadow: 0 0 0 3px rgba(255,255,255,0.2);
  background: rgba(255,255,255,0.2);
}

/* ── Footer ────────────────────────────────── */

.footer {
  padding: 3rem 0 2rem;
  border-top: 1px solid var(--border);
  font-size: 0.875rem;
  color: var(--text-secondary);
}

.footer-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1.25rem;
  text-align: center;
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 0.625rem;
  font-weight: 700;
  font-size: 1rem;
  color: var(--foreground);
}

.footer-links {
  line-height: 1.7;
}

.footer-links a {
  color: var(--primary);
  text-decoration: none;
  font-weight: 500;
}

.footer-links a:hover {
  text-decoration: underline;
}

.footer-copy {
  font-size: 0.8125rem;
  color: var(--muted);
}

/* ── Waitlist Form ─────────────────────────── */

.waitlist-form {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  width: 100%;
  max-width: 440px;
  margin: 0 auto;
}

.waitlist-form input[type="email"] {
  flex: 1;
  font-family: inherit;
  font-size: 1rem;
  padding: 0.875rem 1.25rem;
  border: 1.5px solid var(--border);
  border-radius: 2rem;
  outline: none;
  transition: all 0.15s;
}

.waitlist-form input[type="email"]:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(13, 148, 136, 0.1);
}

.form-message {
  font-size: 0.875rem;
  position: relative;
}

.form-message:not(:empty) {
  margin-top: 0.5rem;
}

.form-message.success {
  color: #16a34a;
}

.form-message.error {
  color: #dc2626;
}

.form-message .msg-link {
  color: var(--primary);
  font-weight: 600;
  text-decoration: none;
}

.form-message .msg-link:hover {
  text-decoration: underline;
}

.signin-link {
  font-size: 0.75rem;
  color: var(--muted);
}

.signin-link a {
  color: var(--primary);
  font-weight: 500;
  text-decoration: none;
}

.signin-link a:hover {
  text-decoration: underline;
}

/* ── Accessibility ─────────────────────────── */

.btn:focus-visible,
a:focus-visible {
  outline: 2px solid var(--primary);
  outline-offset: 2px;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  .btn:hover {
    transform: none;
  }
  .feature-card:hover {
    transform: none;
  }
}

/* ── Responsive ────────────────────────────── */

@media (max-width: 768px) {
  .hero {
    padding: 6.5rem 0 3.5rem;
  }

  .hero h1 {
    font-size: 2.25rem;
  }

  .hero p {
    font-size: 1rem;
  }

  .hero-actions {
    flex-direction: column;
  }

  .waitlist-form {
    flex-direction: column;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: 3.5rem;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.98);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    padding: 1rem 1.5rem;
    gap: 0;
  }

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

  .nav-links li {
    padding: 0.625rem 0;
  }

  .nav-links a {
    font-size: 1rem;
  }

  .nav-cta {
    display: none;
  }

  .nav-hamburger {
    display: flex;
  }

  .nav-mobile-cta {
    display: inline-flex !important;
  }

  .ai-details {
    grid-template-columns: 1fr;
    gap: 1rem;
  }

  .features-grid {
    grid-template-columns: 1fr;
    gap: 1rem;
  }

  .tests-grid {
    grid-template-columns: 1fr;
    gap: 1rem;
  }

  .transparency-steps {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }

  .privacy-points {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }

  .steps {
    grid-template-columns: 1fr;
    gap: 2.5rem;
  }

  .steps::before {
    display: none;
  }

  .section-title {
    font-size: 1.625rem;
  }

  .cta-section h2 {
    font-size: 1.625rem;
  }
}

@media (min-width: 769px) and (max-width: 1024px) {
  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .tests-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .transparency-steps {
    grid-template-columns: repeat(2, 1fr);
  }
}