:root {
  --bg: #F8FAFC; /* iOS-like background */
  --surface: #FFFFFF;
  --surface-elevated: #FFFFFF;
  --text: #1D1D1F; /* Apple-like text color */
  --text-secondary: #86868B; /* iOS secondary text */
  --muted: #8E8E93; /* iOS tertiary text */
  --border: #D1D1D6; /* iOS separator color */
  --primary: #007AFF; /* iOS system blue */
  --primary-600: #0056CC;
  --primary-hover: #0051D5;
  --accent: #5E5CE6; /* iOS purple accent */
  --success: #34C759; /* iOS green */
  --gradient: linear-gradient(135deg, #007AFF 0%, #5E5CE6 100%);
  --gradient-success: linear-gradient(135deg, #34C759 0%, #30D158 100%);
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.12), 0 1px 2px rgba(0, 0, 0, 0.24);
  --shadow: 0 4px 6px rgba(0, 0, 0, 0.07), 0 2px 4px rgba(0, 0, 0, 0.06);
  --shadow-large: 0 10px 15px rgba(0, 0, 0, 0.1), 0 4px 6px rgba(0, 0, 0, 0.05);
  --shadow-hero: 0 25px 50px rgba(0, 122, 255, 0.15);
  --radius: 12px;
  --radius-large: 20px;
}

* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, 'SF Pro Display', 'SF Pro Text', Inter, 'Segoe UI', Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.47059; /* Apple's preferred line height */
  letter-spacing: -0.022em; /* Apple's preferred letter spacing */
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  font-weight: 400;
}

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

.container { max-width: 1120px; margin: 0 auto; padding: 0 24px; }

/* Header */
.site-header { 
  position: sticky; 
  top: 0; 
  z-index: 1000; 
  background: rgba(248, 250, 252, 0.8); 
  backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 0.33px solid rgba(0, 0, 0, 0.1); 
  transition: all 0.3s ease;
}
.header-inner { 
  display: flex; 
  align-items: center; 
  justify-content: space-between; 
  height: 52px; /* Apple-like header height */ 
  max-width: 1240px; 
  margin: 0 auto; 
  padding: 0 24px;
}
.brand { 
  display: flex; 
  align-items: center; 
  gap: 8px; 
  font-weight: 600; 
  color: var(--text);
  font-size: 21px; /* Apple-like brand size */
  letter-spacing: -0.022em;
  text-decoration: none;
  transition: opacity 0.2s ease;
}

.brand:hover {
  opacity: 0.8;
}
.logo { font-size: 24px; }
.brand-name { 
  font-weight: 600; 
}

.nav { 
  display: flex; 
  align-items: center; 
  gap: 32px; 
}
.nav a { 
  color: var(--text); 
  text-decoration: none; 
  font-size: 17px;
  font-weight: 400; 
  transition: color 0.2s ease;
  letter-spacing: -0.022em;
}
.nav a:hover { 
  color: var(--primary); 
}
.nav-toggle { display: none; }

/* Mobile nav panel */
.nav.open {
  display: flex !important;
  position: absolute;
  top: 52px;
  right: 16px;
  flex-direction: column;
  gap: 12px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 12px 16px;
  box-shadow: var(--shadow-large);
  z-index: 1100;
}
.nav.open a {
  font-size: 16px;
}

/* Buttons */
.btn { 
  display: inline-flex; 
  align-items: center; 
  justify-content: center; 
  border-radius: var(--radius); 
  border: none; 
  font-size: 17px;
  font-weight: 590; /* Apple's preferred semi-bold weight */
  cursor: pointer; 
  text-decoration: none; 
  transition: all 0.15s ease;
  letter-spacing: -0.022em;
  min-height: 44px; /* iOS touch target */
}
.btn-small { 
  padding: 8px 16px; 
  font-size: 15px; 
  min-height: 36px;
}
.btn-large { 
  padding: 18px 32px; 
  font-size: 19px; 
  border-radius: 16px;
  min-height: 56px;
}
.btn-primary { 
  background: var(--primary); 
  color: #FFFFFF; 
  box-shadow: var(--shadow);
}
.btn-primary:hover { 
  background: var(--primary-hover); 
  transform: translateY(-0.5px);
  box-shadow: var(--shadow-large);
}
.btn-primary:active { 
  transform: translateY(0);
}
.btn-ghost { 
  color: var(--primary); 
  background: rgba(0, 122, 255, 0.1);
  border: 0.5px solid rgba(0, 122, 255, 0.2);
}
.btn-ghost:hover { 
  background: rgba(0, 122, 255, 0.15);
  transform: translateY(-0.5px);
}

/* Hero */
.hero { 
  padding: 80px 0 60px; 
  position: relative;
}
.hero-inner { 
  display: grid; 
  grid-template-columns: 1fr 0.9fr; 
  gap: 80px; 
  align-items: center; 
  max-width: 1240px; 
  margin: 0 auto; 
  padding: 0 24px;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: rgba(0, 122, 255, 0.1);
  color: var(--primary);
  padding: 6px 14px;
  border-radius: 20px;
  font-size: 15px;
  font-weight: 590;
  margin-bottom: 20px;
  border: 0.5px solid rgba(0, 122, 255, 0.2);
  backdrop-filter: blur(10px);
}

.hero h1 { 
  font-size: 56px; 
  line-height: 1.07143; /* Apple's preferred line height for large text */
  margin: 0 0 20px; 
  letter-spacing: -0.005em; 
  font-weight: 700; /* Apple's preferred bold weight */
  color: var(--text);
}

.gradient-text {
  background: var(--gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.lead { 
  font-size: 21px; 
  color: var(--text-secondary); 
  margin: 0 0 28px; 
  line-height: 1.42857;
  font-weight: 400;
  letter-spacing: -0.022em;
  max-width: 520px;
}

.social-proof {
  display: flex;
  gap: 32px;
  margin: 28px 0;
  flex-wrap: wrap;
}

.proof-item {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 15px;
  color: var(--text-secondary);
  font-weight: 400;
  padding: 8px 0;
}

.cta-row { 
  display: flex; 
  gap: 16px; 
  margin: 40px 0 0; 
  flex-wrap: wrap; 
}

/* Floating Cards */
.hero-visual {
  position: relative;
  padding: 20px;
}

.floating-cards {
  position: relative;
  height: 420px;
}

.experiment-card {
  position: absolute;
  background: var(--surface);
  border: 0.5px solid rgba(0, 0, 0, 0.04);
  border-radius: var(--radius-large);
  padding: 24px;
  box-shadow: var(--shadow);
  width: 260px;
  transition: all 0.3s ease;
  backdrop-filter: blur(10px);
}

.experiment-card:hover {
  transform: translateY(-6px) scale(1.02);
  box-shadow: var(--shadow-hero);
}

.card-1 {
  top: 20px;
  left: 0;
  z-index: 3;
}

.card-2 {
  top: 120px;
  right: 40px;
  z-index: 2;
}

.card-3 {
  top: 250px;
  left: 60px;
  z-index: 1;
}

.card-header {
  font-size: 13px;
  color: var(--muted);
  font-weight: 590;
  text-transform: uppercase;
  letter-spacing: 0.4px;
  margin-bottom: 10px;
}

.card-title {
  font-size: 19px;
  font-weight: 590;
  color: var(--text);
  margin-bottom: 14px;
  line-height: 1.26316;
  letter-spacing: -0.022em;
}

.card-status.completed {
  color: var(--success);
  font-weight: 590;
  font-size: 15px;
}

.card-stats {
  font-size: 17px;
  font-weight: 590;
  margin-bottom: 10px;
  color: var(--text);
}

.progress-bar {
  width: 100%;
  height: 6px;
  background: rgba(0, 122, 255, 0.1);
  border-radius: 3px;
  overflow: hidden;
}

.progress {
  height: 100%;
  background: var(--primary);
  border-radius: 3px;
  transition: width 0.3s ease;
}

.card-insight {
  font-size: 15px;
  font-weight: 400;
  color: var(--text);
  line-height: 1.33333;
}

/* Why Experiments Section */
.why-section {
  padding: 120px 0;
  background: linear-gradient(135deg, var(--bg) 0%, var(--surface) 100%);
}

.why-content {
  max-width: 1240px;
  margin: 0 auto;
}

.why-problem {
  text-align: center;
  margin-bottom: 100px;
}

.why-problem h2 {
  font-size: 40px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 48px;
  letter-spacing: -0.005em;
}

.problem-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 40px;
  margin-top: 48px;
}

.problem-item {
  background: var(--surface);
  border: 0.5px solid rgba(220, 38, 38, 0.1);
  border-radius: var(--radius-large);
  padding: 32px 24px;
  text-align: center;
  transition: all 0.3s ease;
}

.problem-item:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 25px rgba(220, 38, 38, 0.1);
}

.problem-icon {
  font-size: 32px;
  margin-bottom: 20px;
}

.problem-item h3 {
  font-size: 20px;
  font-weight: 590;
  color: #dc2626;
  margin-bottom: 12px;
  letter-spacing: -0.022em;
}

.problem-item p {
  color: var(--text-secondary);
  font-size: 16px;
  line-height: 1.5;
}

.why-solution {
  text-align: center;
}

.breakthrough-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: linear-gradient(135deg, #fef3c7 0%, #fed7aa 100%);
  color: #92400e;
  padding: 8px 20px;
  border-radius: 24px;
  font-size: 16px;
  font-weight: 590;
  margin-bottom: 24px;
  border: 0.5px solid #fbbf24;
}

.why-solution h2 {
  font-size: 40px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 40px;
  letter-spacing: -0.005em;
  line-height: 1.15;
}

.insight-card {
  background: var(--surface);
  border: 0.5px solid rgba(0, 122, 255, 0.1);
  border-radius: var(--radius-large);
  padding: 40px;
  margin: 48px auto;
  max-width: 800px;
  box-shadow: var(--shadow);
}

.insight-card blockquote {
  font-size: 24px;
  font-weight: 500;
  color: var(--text);
  font-style: italic;
  margin: 0 0 20px;
  line-height: 1.4;
  letter-spacing: -0.022em;
}

.insight-card cite {
  font-size: 16px;
  color: var(--primary);
  font-weight: 590;
  font-style: normal;
}

.benefits-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 40px;
  margin-top: 64px;
}

.benefit-item {
  background: var(--surface);
  border: 0.5px solid rgba(0, 122, 255, 0.1);
  border-radius: var(--radius-large);
  padding: 32px 24px;
  text-align: center;
  transition: all 0.3s ease;
}

.benefit-item:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 25px rgba(0, 122, 255, 0.15);
}

.benefit-icon {
  font-size: 32px;
  margin-bottom: 20px;
}

.benefit-item h3 {
  font-size: 20px;
  font-weight: 590;
  color: var(--primary);
  margin-bottom: 12px;
  letter-spacing: -0.022em;
}

.benefit-item p {
  color: var(--text-secondary);
  font-size: 16px;
  line-height: 1.5;
}

/* Screenshots */
.screenshots { 
  padding: 100px 0; 
  background: var(--surface);
}
.screenshots .container {
  max-width: 1240px;
}
.screenshots h2 { 
  text-align: center; 
  margin-bottom: 12px; 
  font-size: 48px;
  font-weight: 700;
  letter-spacing: -0.005em;
  color: var(--text);
}

.section-subtitle {
  text-align: center;
  font-size: 21px;
  color: var(--text-secondary);
  margin-bottom: 64px;
  font-weight: 400;
  letter-spacing: -0.022em;
}

/* Screenshot sections */
.screenshot-section {
  margin-bottom: 88px;
}

.screenshot-section h3 {
  font-size: 32px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 32px;
  text-align: center;
  letter-spacing: -0.005em;
}

.onboarding-grid { 
  display: grid; 
  grid-template-columns: repeat(4, 1fr); 
  gap: 18px; 
}

.creation-grid { 
  display: grid; 
  grid-template-columns: repeat(3, 1fr); 
  gap: 24px; 
}

.tracking-grid { 
  display: grid; 
  grid-template-columns: repeat(3, 1fr); 
  gap: 24px; 
}

.shot { 
  background: var(--surface); 
  border: 0.5px solid rgba(0, 0, 0, 0.04); 
  border-radius: var(--radius-large); 
  overflow: hidden; 
  box-shadow: var(--shadow-sm);
  transition: all 0.25s ease;
}

.shot:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-large);
}

.shot-placeholder {
  aspect-ratio: 9/19.5;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, #f8fafc 0%, #e2e8f0 100%);
  padding: 24px;
}

.placeholder-content {
  text-align: center;
}

.placeholder-icon {
  font-size: 32px;
  margin-bottom: 12px;
}

.placeholder-text {
  font-size: 14px;
  font-weight: 600;
  color: var(--text);
  line-height: 1.4;
}

.placeholder-text small {
  display: block;
  font-size: 12px;
  color: var(--muted);
  font-weight: 400;
  margin-top: 4px;
}

.shots-note { 
  text-align: center; 
  color: var(--muted); 
  margin-top: 24px; 
  font-size: 16px; 
  font-style: italic;
}

/* Real screenshot styling */
.shot img { 
  width: 100%;
  height: auto;
  aspect-ratio: 9/19.5;
  object-fit: cover;
  border-radius: 20px 20px 0 0;
}

.shot figcaption { 
  font-size: 15px; 
  color: var(--text-secondary); 
  padding: 16px 20px; 
  font-weight: 400;
  text-align: center;
  background: var(--surface);
  border-top: 0.5px solid rgba(0, 0, 0, 0.04);
  border-radius: 0 0 var(--radius-large) var(--radius-large);
  letter-spacing: -0.022em;
}

/* Concept */
.concept { 
  padding: 100px 0; 
  background: #fff;
}
.grid-2 { 
  display: grid; 
  grid-template-columns: 1fr 1fr; 
  gap: 64px; 
  align-items: start; 
}
.concept h2 {
  font-size: 36px;
  font-weight: 700;
  margin-bottom: 20px;
}
.list-cards { 
  list-style: none; 
  padding: 0; 
  margin: 24px 0 0; 
  display: grid; 
  gap: 16px; 
}
.list-cards li { 
  background: var(--surface); 
  border: 1px solid var(--border); 
  border-radius: 12px; 
  padding: 20px; 
  transition: transform 0.2s ease;
}
.list-cards li:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}
.concept-card { 
  background: var(--surface); 
  border: 1px solid var(--border); 
  border-radius: 20px; 
  padding: 32px; 
  box-shadow: var(--shadow); 
}
.stat-row { 
  display: grid; 
  grid-template-columns: repeat(3, 1fr); 
  gap: 16px; 
  margin-top: 24px; 
}
.stat { 
  background: linear-gradient(135deg, #fafafa 0%, #f1f5f9 100%); 
  border: 1px solid var(--border); 
  border-radius: 12px; 
  padding: 20px; 
  text-align: center; 
}
.stat-num { 
  font-size: 24px; 
  font-weight: 700; 
  display: block;
  margin-bottom: 4px;
}
.stat-label { 
  font-size: 12px; 
  color: var(--muted); 
  font-weight: 500;
}

/* Features */
.features { 
  padding: 100px 0; 
  background: linear-gradient(135deg, #f8fafc 0%, #ffffff 100%);
}
.features h2 { 
  text-align: center; 
  margin-bottom: 24px; 
  font-size: 36px;
  font-weight: 700;
}
.feature-grid { 
  display: grid; 
  grid-template-columns: repeat(3, 1fr); 
  gap: 32px; 
}
.feature-item { 
  background: var(--surface); 
  border: 1px solid var(--border); 
  border-radius: 20px; 
  padding: 32px; 
  text-align: center;
  transition: transform 0.3s ease;
}
.feature-item:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-large);
}
.feature-item .icon { 
  font-size: 28px; 
  margin-bottom: 16px; 
  display: block;
}
.feature-item h3 {
  font-size: 20px;
  font-weight: 700;
  margin-bottom: 12px;
}
.feature-item p { 
  color: var(--muted); 
  font-size: 16px;
  line-height: 1.6;
}

/* Signup */
.signup { 
  padding: 100px 0; 
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: #fff;
}
.signup h2 {
  color: #fff;
  font-size: 36px;
  font-weight: 700;
  margin-bottom: 20px;
}
.signup p {
  color: rgba(255, 255, 255, 0.9);
  font-size: 18px;
}
.bullets { 
  list-style: none; 
  padding: 0; 
  margin: 24px 0 0; 
  display: grid; 
  gap: 12px; 
  color: rgba(255, 255, 255, 0.9);
}
.bullets li {
  font-size: 16px;
  font-weight: 500;
}
.signup-form { 
  background: rgba(255, 255, 255, 0.95); 
  backdrop-filter: blur(12px);
  border: 1px solid rgba(255, 255, 255, 0.3); 
  border-radius: 20px; 
  padding: 32px; 
  box-shadow: var(--shadow-large);
  min-height: 520px; /* keep layout stable after submit */
  display: grid;
  align-content: start;
}
.signup-form label { 
  display: grid; 
  gap: 8px; 
  font-weight: 600; 
  margin-bottom: 20px; 
  color: var(--text);
}
.signup-form input, .signup-form select { 
  background: #ffffff; 
  border: 1px solid var(--border); 
  color: var(--text); 
  border-radius: 12px; 
  padding: 16px; 
  font-size: 16px;
  transition: border-color 0.2s ease;
}
.signup-form input:focus, .signup-form select:focus { 
  outline: none; 
  border-color: var(--primary); 
  box-shadow: 0 0 0 3px rgba(29, 78, 216, 0.1); 
}
.form-note { 
  color: var(--muted); 
  font-size: 14px; 
  margin-top: 16px; 
}
.form-success, .form-error { 
  font-size: 14px; 
  margin-top: 16px; 
}
.form-success { color: #059669; opacity: 0; transition: opacity 240ms ease; }
.signup-form.submitted .form-success { opacity: 1; }
.form-error { color: #dc2626; }

/* Submitted state: hide fields, show success panel */
.signup-form.submitted label,
.signup-form.submitted button,
.signup-form.submitted .form-note { display: none !important; }
.signup-form.submitted .form-success { 
  display: block !important; 
  font-size: 18px; 
  font-weight: 600; 
  color: #065f46; 
  background: rgba(16, 185, 129, 0.12);
  border: 1px solid rgba(16, 185, 129, 0.25);
  border-radius: 12px;
  padding: 16px;
  margin-top: 8px;
}

/* FAQ */
.faq { 
  padding: 100px 0; 
  background: #fff;
}
.faq h2 { 
  text-align: center; 
  margin-bottom: 48px; 
  font-size: 36px;
  font-weight: 700;
}
.faq-list { 
  display: grid; 
  gap: 16px; 
  max-width: 800px; 
  margin: 0 auto; 
}
.faq details { 
  background: var(--surface); 
  border: 1px solid var(--border); 
  border-radius: 16px; 
  padding: 24px; 
  transition: transform 0.2s ease;
}
.faq details:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}
.faq summary { 
  cursor: pointer; 
  font-weight: 600; 
  font-size: 18px;
  margin-bottom: 12px;
}
.faq p { 
  color: var(--muted); 
  margin-top: 16px;
  line-height: 1.6;
}

/* Footer */
.site-footer { 
  border-top: 1px solid var(--border); 
  margin-top: 0; 
  padding: 48px 0; 
  background: var(--surface); 
}
.footer-inner { 
  display: grid; 
  grid-template-columns: 1fr auto auto; 
  gap: 32px; 
  align-items: center; 
}
.footer-links { 
  display: flex; 
  gap: 24px; 
}
.footer-links a { 
  color: var(--muted); 
  text-decoration: none; 
  font-weight: 500;
}
.footer-links a:hover { 
  color: var(--text); 
  text-decoration: underline; 
  text-underline-offset: 4px; 
}
.legal { 
  display: flex; 
  gap: 12px; 
  color: var(--muted); 
  font-size: 14px; 
}

/* Responsive */
@media (max-width: 1080px) {
  .hero-inner, .grid-2 { grid-template-columns: 1fr; gap: 48px; }
  .hero h1 { font-size: 48px; }
  .hero { padding: 80px 0 60px; }
  .hero-visual { padding: 20px; }
  .floating-cards { height: 300px; }
  .experiment-card { width: 200px; }
  .card-1 { top: 0; left: 0; }
  .card-2 { top: 80px; right: 0; }
  .card-3 { top: 160px; left: 20px; }
  
  .feature-grid { grid-template-columns: 1fr; gap: 24px; }
  .onboarding-grid { grid-template-columns: 1fr 1fr; gap: 16px; }
  .creation-grid { grid-template-columns: 1fr 1fr 1fr; gap: 18px; }
  .tracking-grid { grid-template-columns: 1fr 1fr 1fr; gap: 18px; }
  .problem-grid { grid-template-columns: 1fr; gap: 24px; }
  .benefits-grid { grid-template-columns: 1fr; gap: 24px; }
  .why-problem { margin-bottom: 60px; }
  .why-problem h2 { font-size: 32px; }
  .why-solution h2 { font-size: 32px; }
  .insight-card { padding: 24px; margin: 32px 16px; }
  .insight-card blockquote { font-size: 20px; }
  .footer-inner { grid-template-columns: 1fr; text-align: center; }
  .nav { display: none; }
  .nav-toggle { 
    display: block; 
    background: transparent; 
    color: var(--text); 
    border: none; 
    font-size: 20px; 
    cursor: pointer;
  }
  
  .social-proof { justify-content: center; }
}

@media (max-width: 640px) {
  .hero h1 { font-size: 36px; }
  .onboarding-grid { grid-template-columns: 1fr; gap: 16px; }
  .creation-grid { grid-template-columns: 1fr; gap: 16px; }
  .tracking-grid { grid-template-columns: 1fr; gap: 16px; }
  .cta-row { flex-direction: column; align-items: stretch; }
  .btn-large { text-align: center; }
  .floating-cards { display: none; }
}