:root {
  --zs-ink: #0f172a;
  --zs-slate: #334155;
  --zs-muted: #64748b;
  --zs-forest: #064e3b;
  --zs-emerald: #059669;
  --zs-mint: #d1fae5;
  --zs-amber: #d97706;
  --zs-canvas: #f8fafc;
  --zs-surface: #ffffff;
  --zs-border: #e2e8f0;
  --zs-radius-lg: 16px;
  --zs-radius-md: 10px;
  --zs-shadow: 0 10px 30px -10px rgba(15, 23, 42, 0.08);
  --zs-font-sans: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --zs-font-mono: 'JetBrains Mono', 'Fira Code', monospace;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--zs-font-sans);
  color: var(--zs-ink);
  background-color: var(--zs-canvas);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

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

a {
  color: var(--zs-emerald);
  text-decoration: none;
  transition: color 0.2s ease, background-color 0.2s ease;
}

a:hover {
  color: var(--zs-forest);
}

.zs-shell {
  width: 100%;
  max-width: 1220px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* Top Telemetry Ribbon */
.zs-ribbon {
  background: var(--zs-ink);
  color: #e2e8f0;
  font-size: 0.82rem;
  padding: 0.55rem 0;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.zs-ribbon-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.zs-ribbon-tag {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  font-weight: 600;
  color: #6ee7b7;
}

.zs-ribbon-link {
  color: #93c5fd;
  text-decoration: underline;
  margin-left: 0.4rem;
}

/* Masthead Navigation */
.zs-masthead {
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--zs-border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.zs-masthead-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 78px;
  gap: 1.5rem;
}

.zs-brand {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  color: var(--zs-ink);
}

.zs-brand-badge {
  width: 42px;
  height: 42px;
  border-radius: 10px;
  background: linear-gradient(135deg, var(--zs-forest), var(--zs-emerald));
  color: #ffffff;
  font-weight: 800;
  font-size: 1.15rem;
  display: grid;
  place-items: center;
  letter-spacing: -0.03em;
}

.zs-brand-title {
  display: block;
  font-weight: 800;
  font-size: 1.18rem;
  letter-spacing: -0.02em;
  color: var(--zs-ink);
}

.zs-brand-sub {
  display: block;
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--zs-muted);
  font-weight: 600;
}

.zs-nav-links {
  display: flex;
  align-items: center;
  list-style: none;
  gap: 1.75rem;
}

.zs-nav-item {
  font-size: 0.94rem;
  font-weight: 600;
  color: var(--zs-slate);
  padding: 0.35rem 0;
  border-bottom: 2px solid transparent;
}

.zs-nav-item:hover,
.zs-nav-item.is-current {
  color: var(--zs-emerald);
  border-bottom-color: var(--zs-emerald);
}

.zs-cta-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  background: var(--zs-forest);
  color: #ffffff !important;
  font-weight: 600;
  font-size: 0.9rem;
  padding: 0.65rem 1.25rem;
  border-radius: var(--zs-radius-md);
  border: none;
  cursor: pointer;
  transition: transform 0.15s ease, background-color 0.2s ease;
}

.zs-cta-btn:hover {
  background: var(--zs-emerald);
  transform: translateY(-1px);
}

.zs-cta-outline {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.65rem 1.25rem;
  border-radius: var(--zs-radius-md);
  border: 1px solid var(--zs-border);
  background: var(--zs-surface);
  color: var(--zs-ink) !important;
  font-weight: 600;
  font-size: 0.9rem;
}

.zs-cta-outline:hover {
  border-color: var(--zs-emerald);
  color: var(--zs-emerald) !important;
}

.zs-burger {
  display: none;
  background: transparent;
  border: 1px solid var(--zs-border);
  border-radius: 8px;
  padding: 0.5rem;
  cursor: pointer;
}

.zs-burger span {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--zs-ink);
  margin: 4px 0;
}

.zs-mobile-drawer {
  background: var(--zs-surface);
  border-bottom: 1px solid var(--zs-border);
  padding: 1rem 1.5rem;
}

.zs-mobile-drawer a {
  display: block;
  padding: 0.65rem 0;
  font-weight: 600;
  color: var(--zs-slate);
  border-bottom: 1px solid var(--zs-border);
}

/* Hero Section */
.zs-hero {
  padding: 4.5rem 0 4rem;
  background: radial-gradient(circle at top right, rgba(5, 150, 105, 0.08), transparent 55%), var(--zs-surface);
  border-bottom: 1px solid var(--zs-border);
}

.zs-hero-split {
  display: grid;
  grid-template-columns: 1.12fr 0.88fr;
  gap: 3.25rem;
  align-items: center;
}

.zs-kicker {
  display: inline-block;
  background: var(--zs-mint);
  color: var(--zs-forest);
  font-weight: 700;
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  padding: 0.35rem 0.85rem;
  border-radius: 999px;
  margin-bottom: 1.15rem;
}

.zs-h1 {
  font-size: clamp(2.1rem, 3.8vw, 3.1rem);
  line-height: 1.15;
  font-weight: 800;
  letter-spacing: -0.025em;
  color: var(--zs-ink);
  margin-bottom: 1.2rem;
}

.zs-lead {
  font-size: 1.1rem;
  color: var(--zs-slate);
  margin-bottom: 1.85rem;
}

.zs-hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.9rem;
  margin-bottom: 2.2rem;
}

.zs-metrics-bar {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--zs-border);
}

.zs-metric-num {
  display: block;
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--zs-forest);
  font-family: var(--zs-font-mono);
}

.zs-metric-label {
  font-size: 0.82rem;
  color: var(--zs-muted);
}

.zs-hero-visual {
  position: relative;
  border-radius: var(--zs-radius-lg);
  overflow: hidden;
  box-shadow: var(--zs-shadow);
  border: 1px solid var(--zs-border);
  background: var(--zs-ink);
}

.zs-hero-visual img {
  width: 100%;
  height: 440px;
  object-fit: cover;
}

.zs-visual-caption {
  background: rgba(15, 23, 42, 0.92);
  color: #f8fafc;
  padding: 1rem 1.25rem;
  font-size: 0.85rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

/* Sections */
.zs-section {
  padding: 4.5rem 0;
}

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

.zs-sec-head {
  max-width: 720px;
  margin-bottom: 2.75rem;
}

.zs-h2 {
  font-size: clamp(1.65rem, 2.8vw, 2.25rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: 0.75rem;
  color: var(--zs-ink);
}

.zs-sec-desc {
  color: var(--zs-slate);
  font-size: 1.02rem;
}

/* Bento & Cards */
.zs-grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.75rem;
}

.zs-grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 2rem;
}

.zs-card {
  background: var(--zs-surface);
  border: 1px solid var(--zs-border);
  border-radius: var(--zs-radius-lg);
  padding: 1.85rem;
  box-shadow: var(--zs-shadow);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.zs-card-img {
  width: 100%;
  height: 210px;
  object-fit: cover;
  border-radius: var(--zs-radius-md);
  margin-bottom: 1.25rem;
}

.zs-badge-sm {
  display: inline-block;
  font-size: 0.74rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--zs-emerald);
  margin-bottom: 0.5rem;
}

.zs-h3 {
  font-size: 1.22rem;
  font-weight: 700;
  margin-bottom: 0.65rem;
  color: var(--zs-ink);
}

.zs-card p {
  color: var(--zs-slate);
  font-size: 0.95rem;
  margin-bottom: 1.15rem;
}

/* Interactive Cadence & Stride Lab Calculator */
.zs-lab-box {
  background: linear-gradient(145deg, #0f172a, #1e293b);
  color: #f8fafc;
  border-radius: var(--zs-radius-lg);
  padding: 2.5rem;
  box-shadow: var(--zs-shadow);
}

.zs-lab-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2.5rem;
  align-items: center;
}

.zs-form-group {
  margin-bottom: 1.15rem;
}

.zs-label {
  display: block;
  font-size: 0.86rem;
  font-weight: 600;
  margin-bottom: 0.4rem;
  color: inherit;
}

.zs-input,
.zs-select,
.zs-textarea {
  width: 100%;
  padding: 0.72rem 0.95rem;
  border-radius: 8px;
  border: 1px solid var(--zs-border);
  background: #ffffff;
  color: var(--zs-ink);
  font-family: inherit;
  font-size: 0.95rem;
}

.zs-output-panel {
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.14);
  border-radius: var(--zs-radius-md);
  padding: 1.75rem;
}

.zs-output-row {
  display: flex;
  justify-content: space-between;
  padding: 0.75rem 0;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.zs-output-val {
  font-family: var(--zs-font-mono);
  font-weight: 700;
  color: #6ee7b7;
  font-size: 1.1rem;
}

/* Telemetry Switcher Panels */
.zs-tab-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.65rem;
  margin-bottom: 1.75rem;
}

.zs-tab-trigger {
  padding: 0.6rem 1.15rem;
  border-radius: 999px;
  border: 1px solid var(--zs-border);
  background: var(--zs-surface);
  color: var(--zs-slate);
  font-weight: 600;
  font-size: 0.88rem;
  cursor: pointer;
}

.zs-tab-trigger.is-active {
  background: var(--zs-forest);
  color: #ffffff;
  border-color: var(--zs-forest);
}

.zs-tab-pane {
  display: none;
}

.zs-tab-pane.is-active {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
  align-items: center;
  background: var(--zs-surface);
  padding: 2rem;
  border-radius: var(--zs-radius-lg);
  border: 1px solid var(--zs-border);
}

/* FAQ Accordion */
.zs-faq-stack {
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}

.zs-faq-item {
  background: var(--zs-surface);
  border: 1px solid var(--zs-border);
  border-radius: var(--zs-radius-md);
  overflow: hidden;
}

.zs-faq-btn {
  width: 100%;
  text-align: left;
  padding: 1.15rem 1.35rem;
  background: transparent;
  border: none;
  font-weight: 700;
  font-size: 1rem;
  color: var(--zs-ink);
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
}

.zs-faq-body {
  display: none;
  padding: 0 1.35rem 1.25rem;
  color: var(--zs-slate);
  font-size: 0.95rem;
}

.zs-faq-item.is-open .zs-faq-body {
  display: block;
}

/* Legal & Policy Prose */
.zs-prose {
  max-width: 860px;
  margin: 0 auto;
  background: var(--zs-surface);
  padding: 2.75rem;
  border-radius: var(--zs-radius-lg);
  border: 1px solid var(--zs-border);
}

.zs-prose h1 {
  font-size: 2rem;
  margin-bottom: 0.75rem;
}

.zs-prose h2 {
  font-size: 1.35rem;
  margin: 1.85rem 0 0.65rem;
  color: var(--zs-forest);
}

.zs-prose p, .zs-prose li {
  color: var(--zs-slate);
  margin-bottom: 0.85rem;
}

.zs-prose ul {
  padding-left: 1.35rem;
  margin-bottom: 1rem;
}

.zs-table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.25rem 0;
  font-size: 0.9rem;
}

.zs-table th, .zs-table td {
  border: 1px solid var(--zs-border);
  padding: 0.75rem;
  text-align: left;
}

.zs-table th {
  background: var(--zs-canvas);
  font-weight: 700;
}

/* Alert / Form status */
.zs-form-status {
  margin-top: 1rem;
  padding: 0.9rem 1.1rem;
  border-radius: 8px;
  font-size: 0.92rem;
  display: none;
}

.zs-form-status.is-ok {
  display: block;
  background: var(--zs-mint);
  color: var(--zs-forest);
  border: 1px solid #6ee7b7;
}

.zs-form-status.is-err {
  display: block;
  background: #fee2e2;
  color: #991b1b;
  border: 1px solid #fca5a5;
}

/* Footer */
.zs-footer {
  background: var(--zs-ink);
  color: #cbd5e1;
  padding: 4rem 0 2.5rem;
  margin-top: 3rem;
}

.zs-footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1.2fr;
  gap: 2.25rem;
  padding-bottom: 2.5rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.zs-footer-title {
  color: #ffffff;
  font-weight: 700;
  font-size: 0.95rem;
  margin-bottom: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.zs-footer-list {
  list-style: none;
}

.zs-footer-list li {
  margin-bottom: 0.55rem;
}

.zs-footer-list a {
  color: #cbd5e1;
  font-size: 0.9rem;
}

.zs-footer-list a:hover {
  color: #6ee7b7;
}

.zs-footer-bottom {
  padding-top: 1.75rem;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
  font-size: 0.84rem;
  color: #94a3b8;
}

/* GDPR Cookie Toast */
.zs-cookie-toast {
  position: fixed;
  bottom: 1.25rem;
  right: 1.25rem;
  left: 1.25rem;
  max-width: 560px;
  background: var(--zs-ink);
  color: #f8fafc;
  padding: 1.35rem;
  border-radius: var(--zs-radius-md);
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
  border: 1px solid rgba(255, 255, 255, 0.15);
  z-index: 999;
}

.zs-cookie-actions {
  display: flex;
  gap: 0.75rem;
  margin-top: 0.95rem;
}

@media (max-width: 920px) {
  .zs-hero-split,
  .zs-lab-grid,
  .zs-grid-3,
  .zs-grid-2,
  .zs-tab-pane.is-active,
  .zs-footer-grid {
    grid-template-columns: 1fr;
  }
  .zs-nav-links {
    display: none;
  }
  .zs-burger {
    display: block;
  }
}