:root {
  --primary-700: #0f766e;
  --primary-600: #0d9488;
  --primary-500: #14b8a6;
  --accent-blue: #2563eb;
  --bg-app: #f8fafc;
  --bg-surface: #ffffff;
  --border: #e2e8f0;
  --text-primary: #0f172a;
  --text-secondary: #64748b;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 20px;
  --font: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --container-width: 1120px;
  --container-width-narrow: 760px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font);
  color: var(--text-primary);
  background: var(--bg-app);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

.container--narrow {
  max-width: var(--container-width-narrow);
}

/* Nav */
.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(248, 250, 252, 0.85);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}

.nav__inner {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 14px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.nav__brand { display: flex; align-items: center; }
.nav__logo { height: 26px; display: block; }

.nav__links {
  display: flex;
  gap: 28px;
  flex: 1;
  justify-content: center;
}

.nav__links a {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
  transition: color 0.15s ease;
}

.nav__links a:hover { color: var(--primary-600); }

.nav__cta { white-space: nowrap; }

@media (max-width: 720px) {
  .nav__links { display: none; }
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 20px;
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: 14px;
  text-decoration: none;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.15s ease, background 0.15s ease;
}

.btn--ghost {
  background: transparent;
  border-color: var(--border);
  color: var(--text-primary);
}
.btn--ghost:hover { border-color: var(--primary-500); color: var(--primary-700); }

.btn--primary {
  background: var(--primary-600);
  color: #fff;
  box-shadow: 0 8px 20px -6px rgba(13, 148, 136, 0.5);
}
.btn--primary:hover { background: var(--primary-700); transform: translateY(-1px); }

.btn--lg { padding: 14px 28px; font-size: 16px; }

/* Hero */
.hero {
  padding: 96px 0 64px;
  text-align: center;
  background:
    radial-gradient(60% 60% at 50% 0%, rgba(20, 184, 166, 0.12), transparent),
    var(--bg-app);
}

.eyebrow {
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-size: 12px;
  font-weight: 700;
  color: var(--primary-600);
  margin: 0 0 12px;
}

.hero h1 {
  font-size: clamp(36px, 6vw, 56px);
  font-weight: 800;
  margin: 0 0 24px;
  letter-spacing: -0.02em;
}

.hero__lede {
  max-width: 720px;
  margin: 0 auto 20px;
  font-size: 18px;
  color: var(--text-secondary);
}

.hero__role {
  max-width: 640px;
  margin: 0 auto 32px;
  font-size: 16px;
  font-weight: 600;
  color: var(--text-primary);
}

.hero__tags {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px;
}

.tag {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  padding: 6px 14px;
  border-radius: 999px;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-secondary);
}

/* Sections */
.section { padding: 72px 0; }
.section--alt { background: var(--bg-surface); border-top: 1px solid var(--border); border-bottom: 1px solid var(--border); }

.section__title {
  font-size: 28px;
  font-weight: 800;
  margin: 0 0 16px;
  letter-spacing: -0.01em;
}

.section__intro {
  color: var(--text-secondary);
  font-size: 16px;
  margin: 0 0 32px;
}

.list { padding-left: 20px; color: var(--text-secondary); }
.list li { margin-bottom: 8px; }

/* Gallery */
.gallery {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.shot {
  margin: 0;
  aspect-ratio: 3 / 4;
  border-radius: var(--radius-lg);
  border: 1.5px dashed var(--border);
  background: linear-gradient(160deg, #f1f5f9, #e2e8f0);
  display: flex;
  align-items: flex-end;
  overflow: hidden;
}

.shot figcaption {
  width: 100%;
  padding: 14px;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-secondary);
  background: rgba(255,255,255,0.7);
  text-align: center;
}

@media (max-width: 860px) {
  .gallery { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 560px) {
  .gallery { grid-template-columns: 1fr; }
}

/* Solution grid */
.solution-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  margin: 28px 0;
}

.solution-card {
  background: var(--bg-app);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 24px;
}

.solution-card h3 {
  font-size: 16px;
  margin: 0 0 10px;
  color: var(--primary-700);
}

.solution-card p {
  margin: 0;
  color: var(--text-secondary);
  font-size: 14px;
}

@media (max-width: 800px) {
  .solution-grid { grid-template-columns: 1fr; }
}

/* Responsibility */
.responsibility-grid {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.responsibility-item {
  background: var(--bg-app);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 18px 20px;
  color: var(--text-secondary);
  font-size: 15px;
}

.responsibility-verb {
  display: inline-block;
  background: var(--primary-600);
  color: #fff;
  font-weight: 700;
  font-size: 13px;
  padding: 3px 10px;
  border-radius: 999px;
  margin-right: 10px;
}

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

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

.feature-number {
  font-size: 13px;
  font-weight: 800;
  color: var(--primary-500);
  margin-bottom: 12px;
}

.feature-card h3 { margin: 0 0 10px; font-size: 17px; }
.feature-card p { margin: 0; color: var(--text-secondary); font-size: 14px; }

@media (max-width: 900px) {
  .feature-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 600px) {
  .feature-grid { grid-template-columns: 1fr; }
}

/* Diagram */
.diagram-card {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 32px;
  overflow-x: auto;
}

.diagram-card .mermaid { display: flex; justify-content: center; }

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

.challenge-card {
  border-left: 3px solid var(--primary-500);
  padding: 4px 0 4px 20px;
}

.challenge-card h3 { margin: 0 0 10px; font-size: 16px; }
.challenge-card p { margin: 0; color: var(--text-secondary); font-size: 14px; }
.challenge-card code {
  background: var(--bg-app);
  padding: 1px 6px;
  border-radius: 4px;
  font-size: 13px;
}

@media (max-width: 900px) {
  .challenge-grid { grid-template-columns: 1fr; }
}

/* Stats */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.stat {
  background: var(--bg-app);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px 20px;
  text-align: center;
}

.stat__number {
  display: block;
  font-size: 40px;
  font-weight: 800;
  color: var(--primary-600);
  line-height: 1;
  margin-bottom: 10px;
}

.stat__label {
  display: block;
  font-size: 13px;
  color: var(--text-secondary);
  font-weight: 500;
}

@media (max-width: 800px) {
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 500px) {
  .stats-grid { grid-template-columns: 1fr; }
}

/* Tech table */
.tech-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
}

.tech-table tr { border-bottom: 1px solid var(--border); }
.tech-table tr:last-child { border-bottom: none; }

.tech-table th, .tech-table td {
  text-align: left;
  padding: 14px 12px;
  vertical-align: top;
}

.tech-table th {
  color: var(--text-primary);
  font-weight: 700;
  width: 38%;
  white-space: nowrap;
}

.tech-table td { color: var(--text-secondary); }

@media (max-width: 600px) {
  .tech-table th, .tech-table td { display: block; width: 100%; white-space: normal; }
  .tech-table th { padding-bottom: 4px; }
  .tech-table td { padding-top: 0; padding-bottom: 18px; }
}

/* CTA */
.cta {
  padding: 96px 0;
  text-align: center;
  background: linear-gradient(160deg, var(--primary-700), var(--primary-500));
  color: #fff;
}

.cta h2 { font-size: 32px; margin: 0 0 8px; font-weight: 800; }
.cta p { font-size: 17px; margin: 0 0 32px; opacity: 0.9; }
.cta .btn--primary { background: #fff; color: var(--primary-700); box-shadow: none; }
.cta .btn--primary:hover { background: #f0fdfa; }

/* Footer */
.footer {
  padding: 40px 0;
  text-align: center;
  color: var(--text-secondary);
  font-size: 13px;
}

.footer__logo { height: 20px; margin-bottom: 12px; opacity: 0.7; }