/* Design tokens — Flat / Minimal / Technical */
:root {
  --bg: #FAFAFA;
  --surface: #FFFFFF;
  --text-primary: #171717;
  --text-muted: #737373;
  --accent: #2563EB;
  --accent-hover: #1D4ED8;
  --accent-muted: #EFF6FF;
  --code-bg: #F4F4F5;
  --border: #E5E5E5;
  --success: #16A34A;
  --font-sans: "Inter", system-ui, -apple-system, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, monospace;
  --max-width: 1120px;
  --section-y: 96px;
  --radius: 8px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.65;
  color: var(--text-primary);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}

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

ul, ol {
  list-style: none;
}

code {
  font-family: var(--font-mono);
  font-size: 0.875em;
  background: var(--code-bg);
  padding: 0.15em 0.4em;
  border-radius: 4px;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

.container.narrow {
  max-width: 720px;
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(250, 250, 250, 0.9);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
  gap: 24px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 600;
  font-size: 15px;
}

.logo-mark {
  font-family: var(--font-mono);
  color: var(--accent);
  font-size: 14px;
}

.nav {
  display: flex;
  gap: 28px;
}

.nav a {
  font-size: 14px;
  color: var(--text-muted);
  transition: color 0.15s;
}

.nav a:hover {
  color: var(--text-primary);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  height: 48px;
  padding: 0 24px;
  font-size: 15px;
  font-weight: 500;
  border-radius: var(--radius);
  border: 1px solid transparent;
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s;
}

.btn-sm {
  height: 40px;
  padding: 0 16px;
  font-size: 14px;
}

.btn-block {
  width: 100%;
}

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

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

.btn-secondary {
  background: transparent;
  border-color: var(--border);
  color: var(--text-primary);
}

.btn-secondary:hover {
  border-color: var(--text-muted);
}

/* Sections */
.section {
  padding: var(--section-y) 0;
}

.section-alt {
  background: var(--surface);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.section-label {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--accent);
  margin-bottom: 12px;
  letter-spacing: 0.02em;
}

h1 {
  font-size: clamp(36px, 5vw, 48px);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.02em;
}

h2 {
  font-size: clamp(26px, 3.5vw, 32px);
  font-weight: 600;
  line-height: 1.25;
  letter-spacing: -0.01em;
  margin-bottom: 48px;
}

h3 {
  font-size: 18px;
  font-weight: 600;
  line-height: 1.35;
  margin-bottom: 8px;
}

.section-desc {
  font-size: 18px;
  color: var(--text-muted);
  line-height: 1.7;
}

.lead {
  font-size: 18px;
  color: var(--text-muted);
  margin-top: 20px;
  max-width: 520px;
}

/* Hero */
.hero {
  padding-top: 80px;
  padding-bottom: 80px;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: center;
}

.pill-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 24px;
}

.pill {
  font-family: var(--font-mono);
  font-size: 12px;
  padding: 4px 12px;
  background: var(--accent-muted);
  color: var(--accent);
  border-radius: 999px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 32px;
}

.hero-visual {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

/* Flow diagram */
.flow-diagram {
  display: flex;
  align-items: center;
  gap: 0;
  overflow-x: auto;
  padding: 4px 0;
}

.flow-node {
  flex-shrink: 0;
  width: 100px;
  padding: 14px 10px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  text-align: center;
}

.flow-node-accent {
  border-color: var(--accent);
  background: var(--accent-muted);
}

.flow-label {
  display: block;
  font-size: 12px;
  font-weight: 600;
  color: var(--accent);
}

.flow-sub {
  display: block;
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--text-muted);
  margin-top: 4px;
}

.flow-arrow {
  flex-shrink: 0;
  width: 20px;
  height: 2px;
  background: var(--accent);
  position: relative;
}

.flow-arrow::after {
  content: "";
  position: absolute;
  right: 0;
  top: -3px;
  border: 4px solid transparent;
  border-left-color: var(--accent);
}

/* Code block */
.code-block {
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.6;
  background: var(--code-bg);
  border-left: 3px solid var(--accent);
  border-radius: 0 var(--radius) var(--radius) 0;
  padding: 16px 20px;
  overflow-x: auto;
}

.code-comment { color: var(--text-muted); }
.code-kw { color: var(--accent); }
.code-str { color: var(--success); }
.code-fn { color: var(--text-primary); }
.code-tag { color: #9333EA; }

/* Cards */
.card-grid {
  display: grid;
  gap: 24px;
}

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

.card-grid-3 {
  grid-template-columns: repeat(3, 1fr);
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
}

.card-num {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--accent);
  display: block;
  margin-bottom: 16px;
}

.card p {
  color: var(--text-muted);
  font-size: 15px;
}

.card-horizontal {
  display: flex;
  gap: 20px;
  align-items: flex-start;
}

.usecase-icon {
  font-size: 24px;
  color: var(--accent);
  line-height: 1;
  flex-shrink: 0;
}

/* Steps */
.steps {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.step {
  display: flex;
  gap: 24px;
  padding: 32px 0;
  border-bottom: 1px solid var(--border);
}

.step:first-child {
  border-top: 1px solid var(--border);
}

.step-num {
  flex-shrink: 0;
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 500;
  color: var(--accent);
  background: var(--accent-muted);
  border-radius: var(--radius);
}

.step p {
  color: var(--text-muted);
  font-size: 15px;
}

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

.metric-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px;
  text-align: center;
}

.metric-before,
.metric-after {
  font-size: 15px;
  color: var(--text-muted);
}

.metric-before strong {
  color: var(--text-muted);
  text-decoration: line-through;
}

.metric-after strong {
  color: var(--success);
  font-size: 28px;
}

.metric-arrow {
  font-size: 20px;
  color: var(--accent);
  margin: 8px 0;
}

.metric-value {
  font-size: 36px;
  font-weight: 700;
  color: var(--accent);
  line-height: 1.2;
}

.metric-label {
  margin-top: 12px;
  font-size: 14px;
  color: var(--text-muted);
}

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

.tech-group h3 {
  margin-bottom: 16px;
}

.tech-list li {
  padding: 8px 0;
  font-size: 15px;
  color: var(--text-muted);
  border-bottom: 1px solid var(--border);
}

.tech-list li:last-child {
  border-bottom: none;
}

/* Proof */
.proof-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.proof-placeholder {
  aspect-ratio: 16 / 10;
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 8px;
}

.proof-placeholder span {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--accent);
}

.proof-placeholder p {
  font-size: 14px;
  color: var(--text-muted);
}

.proof-card figcaption {
  margin-top: 12px;
  font-size: 14px;
  color: var(--text-muted);
}

/* Plans */
.card-plan ul {
  margin: 20px 0 28px;
}

.card-plan li {
  font-size: 15px;
  color: var(--text-muted);
  padding: 6px 0;
  padding-left: 16px;
  position: relative;
}

.card-plan li::before {
  content: "·";
  position: absolute;
  left: 0;
  color: var(--accent);
}

.plan-duration {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--accent);
  margin-bottom: 4px;
}

.card-plan-featured {
  border-color: var(--accent);
  position: relative;
}

.plan-badge {
  position: absolute;
  top: -10px;
  right: 20px;
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  background: var(--accent);
  color: #fff;
  padding: 2px 10px;
  border-radius: 999px;
}

/* FAQ */
.faq-list {
  display: flex;
  flex-direction: column;
}

.faq-item {
  border-bottom: 1px solid var(--border);
}

.faq-item summary {
  padding: 20px 0;
  font-weight: 500;
  cursor: pointer;
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.faq-item summary::-webkit-details-marker {
  display: none;
}

.faq-item summary::after {
  content: "+";
  font-family: var(--font-mono);
  font-size: 18px;
  color: var(--text-muted);
  transition: transform 0.2s;
}

.faq-item[open] summary::after {
  content: "−";
}

.faq-item p {
  padding-bottom: 20px;
  font-size: 15px;
  color: var(--text-muted);
}

/* CTA */
.cta-section {
  background: var(--text-primary);
  color: #fff;
}

.cta-inner {
  text-align: center;
}

.cta-inner h2 {
  color: #fff;
  margin-bottom: 16px;
}

.cta-inner p {
  color: #A3A3A3;
  font-size: 18px;
  margin-bottom: 8px;
}

.cta-section .btn-secondary {
  border-color: #404040;
  color: #fff;
}

.cta-section .btn-secondary:hover {
  border-color: #737373;
}

/* Footer */
.site-footer {
  padding: 48px 0;
  border-top: 1px solid var(--border);
}

.footer-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.footer-logo {
  font-weight: 600;
  font-size: 14px;
}

.footer-nav {
  display: flex;
  gap: 24px;
}

.footer-nav a {
  font-size: 13px;
  color: var(--text-muted);
}

.footer-nav a:hover {
  color: var(--text-primary);
}

.footer-copy {
  width: 100%;
  text-align: center;
  font-size: 12px;
  color: var(--text-muted);
  margin-top: 16px;
}

/* Responsive */
@media (max-width: 900px) {
  .hero-grid,
  .card-grid-3,
  .metric-grid,
  .tech-grid,
  .proof-grid {
    grid-template-columns: 1fr;
  }

  .hero-grid {
    gap: 40px;
  }

  .card-grid-2 {
    grid-template-columns: 1fr;
  }

  .nav {
    display: none;
  }

  :root {
    --section-y: 64px;
  }
}