/* ==========================================================================
   Pure Air Nova — Sustainability
   ========================================================================== */

:root {
  --color-bg: #faf9f5;
  --color-surface: #f7f5ef;
  --color-green: #2f6f49;
  --color-green-dark: #234f34;
  --color-dark: #132431;
  --color-muted: #58635f;
  --color-border: #e6e2d9;
  --radius: 16px;
  --radius-sm: 12px;
  --container-width: 1200px;

  --font-serif: ui-serif, Georgia, Cambria, "Times New Roman", Times, serif;
  --font-sans: system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;

  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 24px;
  --space-6: 32px;
  --space-7: 48px;
  --space-8: 64px;
  --space-9: 96px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
}

body {
  margin: 0;
  background: var(--color-bg);
  color: var(--color-dark);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }

.container {
  width: 100%;
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 var(--space-5);
}

.icon {
  width: 1em;
  height: 1em;
  fill: none;
  stroke: #2f6f49;
  flex-shrink: 0;
}

.eyebrow {
  font-family: var(--font-sans);
  font-size: 12.5px;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-green);
  margin: 0 0 var(--space-3);
}

h1, h2, h3 {
  font-family: var(--font-serif);
  font-weight: 400;
  color: var(--color-dark);
  margin: 0;
}

.section { padding: var(--space-8) 0; }
.section-border-top { border-top: 1px solid var(--color-border); }

/* ==========================================================================
   Nav
   ========================================================================== */

.site-nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(250, 249, 245, 0.92);
  backdrop-filter: saturate(140%) blur(6px);
  border-bottom: 1px solid var(--color-border);
}

.site-nav .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  height: 76px;
}

.brand {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-sans);
  font-weight: 700;
  font-size: 15px;
  letter-spacing: 0.06em;
  color: var(--color-dark);
  white-space: nowrap;
}

.brand .icon { width: 20px; height: 20px; color: var(--color-green); }

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-6);
  list-style: none;
  margin: 0;
  padding: 0;
  font-size: 14.5px;
}

.nav-links a {
  color: var(--color-dark);
  padding-bottom: 4px;
  border-bottom: 2px solid transparent;
}

.nav-links a.is-active {
  color: var(--color-green);
  font-weight: 600;
  border-bottom-color: var(--color-green);
}

/* ==========================================================================
   Hero
   ========================================================================== */

.hero { padding: var(--space-8) 0 var(--space-7); }

.hero .container {
  display: grid;
  grid-template-columns: minmax(0, 0.85fr) minmax(0, 1.15fr);
  gap: var(--space-7);
  align-items: center;
}

.hero-copy h1 {
  font-size: clamp(42px, 5vw, 62px);
  line-height: 1.05;
  margin: var(--space-2) 0 var(--space-4);
}

.hero-statement {
  font-family: var(--font-sans);
  font-size: 18px;
  font-weight: 600;
  color: var(--color-green);
  line-height: 1.4;
  margin: 0 0 var(--space-4);
}

.hero-copy p.body {
  font-size: 15.5px;
  color: var(--color-dark);
  max-width: 46ch;
  margin: 0 0 var(--space-5);
}

.hero-concepts {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-size: 14px;
  font-weight: 600;
}

.hero-concepts .concept {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.hero-concepts .icon { width: 17px; height: 17px; color: var(--color-green); }

.hero-concepts .dot {
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: var(--color-border);
}

.hero-visual img {
  width: 100%;
  height: auto;
  object-fit: contain;
}

/* ==========================================================================
   Section 3 — Sustainability Direction tabs
   ========================================================================== */

.direction-panel {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  overflow: hidden;
}

.tab-list {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  list-style: none;
  margin: 0;
  padding: 0;
  border-bottom: 1px solid var(--color-border);
}

.tab-btn {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  width: 100%;
  background: transparent;
  border: none;
  border-left: 1px solid var(--color-border);
  padding: var(--space-5);
  cursor: pointer;
  text-align: left;
  font-family: var(--font-sans);
  color: var(--color-dark);
  transition: background-color 0.3s ease;
}
.tab-btn:first-child { border-left: none; }

.tab-btn .icon-wrap {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--color-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  transition: background-color 0.3s ease;
}

.tab-btn .icon { width: 19px; height: 19px; color: var(--color-green); }

.tab-btn .tab-num {
  display: block;
  font-size: 12px;
  font-weight: 700;
  color: var(--color-muted);
  margin-bottom: 2px;
}

.tab-btn .tab-label {
  display: block;
  font-size: 14.5px;
  font-weight: 700;
  letter-spacing: 0.02em;
  position: relative;
  padding-bottom: 6px;
}

.tab-btn .tab-label::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 22px;
  height: 2px;
  background: var(--color-green);
  opacity: 0;
  transition: opacity 0.3s ease;
}

.tab-btn[aria-selected="true"] {
  background: var(--color-bg);
}
.tab-btn[aria-selected="true"] .tab-num,
.tab-btn[aria-selected="true"] .tab-label { color: var(--color-green); }
.tab-btn[aria-selected="true"] .tab-label::after { opacity: 1; }

.tab-panels { position: relative; }

.tab-panel {
  display: none;
  grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.4fr);
  gap: var(--space-6);
  padding: var(--space-7) var(--space-6);
  align-items: center;
  opacity: 0;
  transition: opacity 0.3s ease;
}

.tab-panel.is-active {
  display: grid;
  opacity: 1;
}

.tab-panel-decor {
  display: flex;
  align-items: flex-start;
  justify-content: center;
  color: var(--color-border);
}

.tab-panel-decor .icon { width: 100%; height: auto; max-width: 130px; }

.tab-panel-text .point + .point {
  margin-top: var(--space-5);
  padding-top: var(--space-5);
  border-top: 1px solid var(--color-border);
}

.tab-panel-text .point h3 {
  font-family: var(--font-sans);
  font-size: 17px;
  font-weight: 700;
  margin-bottom: var(--space-2);
}

.tab-panel-text .point p {
  font-size: 14.5px;
  color: var(--color-muted);
  margin: 0;
  max-width: 40ch;
}

.tab-panel-visual {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
}

.tab-panel-visual img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 2;
  object-fit: contain;
  border-radius: var(--radius-sm);
}

.tab-dots {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding-bottom: var(--space-5);
}

.tab-dots .dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--color-border);
}

.tab-dots .dot.is-active { background: var(--color-green); }

/* ==========================================================================
   Section 4 — Materials Direction
   ========================================================================== */

.materials-layout {
  display: grid;
  grid-template-columns: minmax(0, 0.85fr) minmax(0, 1.15fr);
  gap: var(--space-7);
  align-items: center;
}

.materials-copy h2 {
  font-size: clamp(28px, 3.2vw, 36px);
  line-height: 1.2;
  margin-bottom: var(--space-4);
}

.materials-copy p {
  font-size: 15.5px;
  color: var(--color-muted);
  max-width: 44ch;
  margin: 0;
}

.factor-diagram {
  position: relative;
 
  align-items: center;
  justify-items: center;
  gap: var(--space-3) 0;
  min-height: 300px;
}

.factor-lines {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  z-index: 0;
  pointer-events: none;
}

.factor-lines path {
  fill: none;
  stroke: var(--color-border);
  stroke-width: 0.6;
  stroke-dasharray: 2 2;
}

.factor-diagram .fd-center {
  grid-column: 2 / 3;
  grid-row: 1 / 4;
  width: 100%;
  max-width: 260px;
}

.factor-diagram .fd-center img {
  width: 100%;
  height: auto;
  object-fit: contain;
}

.factor {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-2);
  text-align: center;
  z-index: 1;
}

.factor .icon-wrap {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
}

.factor .icon { width: 19px; height: 19px; color: var(--color-green); }

.factor span {
  font-size: 12.5px;
  font-weight: 700;
  color: var(--color-dark);
  max-width: 92px;
  line-height: 1.3;
}

.factor-performance { grid-column: 2 / 3; grid-row: 1; align-self: start; }
.factor-safety { grid-column: 1 / 2; grid-row: 2; }
.factor-durability { grid-column: 3 / 4; grid-row: 2; }
.factor-environmental { grid-column: 1 / 2; grid-row: 3; align-self: end; }
.factor-manufacturability { grid-column: 3 / 4; grid-row: 3; align-self: end; }

/* ==========================================================================
   Section 5 — Modularity
   ========================================================================== */

.modularity-layout {
  display: grid;
  grid-template-columns: minmax(0, 0.7fr) minmax(0, 1.3fr);
  gap: var(--space-7);
  align-items: start;
}

.modularity-copy h2 {
  font-size: clamp(28px, 3.2vw, 36px);
  line-height: 1.2;
  margin-bottom: var(--space-4);
}

.modularity-copy p {
  font-size: 15.5px;
  color: var(--color-muted);
  max-width: 42ch;
  margin: 0 0 var(--space-5);
}

.modularity-visual img {
  width: 100%;
  height: auto;
}

.modularity-steps {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-5);
  margin-top: var(--space-6);
}

.step .step-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--color-green);
  color: #fdfbf7;
  font-size: 12px;
  font-weight: 700;
  margin-bottom: var(--space-3);
}

.step h3 {
  font-family: var(--font-sans);
  font-size: 14.5px;
  font-weight: 700;
  margin-bottom: var(--space-2);
  line-height: 1.35;
}

.step p {
  font-size: 13.5px;
  color: var(--color-muted);
  margin: 0;
  line-height: 1.45;
}

/* ==========================================================================
   Section 6 — Future Circularity
   ========================================================================== */

.circularity-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 0.8fr);
  gap: var(--space-6);
  align-items: center;
}

.circularity-copy h2 {
  font-size: clamp(28px, 3.2vw, 36px);
  line-height: 1.2;
  margin-bottom: var(--space-4);
}

.circularity-copy p {
  font-size: 15.5px;
  color: var(--color-muted);
  max-width: 42ch;
  margin: 0;
}

.circularity-concepts {
  display: flex;
  align-items: flex-start;
  justify-content: center;
  gap: var(--space-5);
}

.circularity-concepts .concept {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-2);
  text-align: center;
}

.circularity-concepts .icon-wrap {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
}

.circularity-concepts .icon { width: 20px; height: 20px; color: var(--color-green); }

.circularity-concepts span {
  font-size: 12.5px;
  font-weight: 700;
}

.circularity-divider {
  width: 1px;
  align-self: stretch;
  background: var(--color-border);
  margin: var(--space-2) 0;
}

.dev-note {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: var(--space-5);
}

.dev-note-head {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  margin-bottom: var(--space-3);
}

.dev-note-head .icon { width: 15px; height: 15px; color: var(--color-green); }

.dev-note-head span {
  font-size: 11.5px;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--color-dark);
}

.dev-note p {
  font-size: 13px;
  color: var(--color-muted);
  line-height: 1.55;
  margin: 0 0 var(--space-3);
}

.dev-note a {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 12.5px;
  font-weight: 700;
  color: var(--color-green);
}

.dev-note a .icon { width: 13px; height: 13px; }

/* ==========================================================================
   Section 7 — CTA
   ========================================================================== */

.cta-section { padding: var(--space-8) 0; }

.cta-layout {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-6);
  flex-wrap: wrap;
}

.cta-copy h2 {
  font-size: clamp(26px, 3vw, 32px);
  line-height: 1.2;
  margin-bottom: var(--space-2);
}

.cta-copy p {
  color: var(--color-muted);
  font-size: 14.5px;
  margin: 0;
}

.cta-actions {
  display: flex;
  gap: var(--space-3);
  flex-shrink: 0;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  font-family: var(--font-sans);
  font-size: 14px;
  font-weight: 600;
  padding: 12px 20px;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  cursor: pointer;
  white-space: nowrap;
  transition: background-color 0.15s ease, border-color 0.15s ease, color 0.15s ease;
}

.btn .icon { width: 15px; height: 15px; }

.btn-outline {
  background: transparent;
  border-color: var(--color-border);
  color: var(--color-green);
}
.btn-outline:hover { border-color: var(--color-green); }

.btn-solid {
  background: var(--color-green);
  border-color: var(--color-green);
  color: #fdfbf7;
}
.btn-solid:hover { background: var(--color-green-dark); border-color: var(--color-green-dark); }

.btn-ghost-outline {
  background: transparent;
  border-color: var(--color-border);
  color: var(--color-dark);
}
.btn-ghost-outline:hover { border-color: var(--color-green); color: var(--color-green); }

/* ==========================================================================
   Footer
   ========================================================================== */

.site-footer {
  border-top: 1px solid var(--color-border);
  padding: var(--space-8) 0 var(--space-6);
}

.footer-top {
  display: grid;
  grid-template-columns: minmax(0, 1.3fr) repeat(3, minmax(0, 0.85fr));
  gap: var(--space-6);
  margin-bottom: var(--space-7);
}

.footer-brand .brand { margin-bottom: var(--space-3); }

.footer-brand p {
  color: var(--color-muted);
  font-size: 13.5px;
  max-width: 32ch;
  margin: 0 0 var(--space-4);
  line-height: 1.5;
}

.footer-pill {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  border: 1px solid var(--color-border);
  border-radius: 999px;
  padding: 7px 14px;
  font-size: 12.5px;
  font-weight: 600;
  color: var(--color-dark);
}

.footer-pill .icon { width: 15px; height: 15px; color: var(--color-green); }

.footer-col h3 {
  font-family: var(--font-sans);
  font-size: 14px;
  font-weight: 700;
  margin-bottom: var(--space-3);
}

.footer-col ul { list-style: none; margin: 0; padding: 0; }
.footer-col li { margin-bottom: var(--space-2); }

.footer-col a {
  font-size: 13.5px;
  color: var(--color-muted);
}
.footer-col a:hover { color: var(--color-green); }

.footer-legal {
  border-top: 1px solid var(--color-border);
  padding-top: var(--space-5);
  text-align: center;
  font-size: 12px;
  color: var(--color-muted);
  line-height: 1.7;
}

/* ==========================================================================
   Responsive
   ========================================================================== */

@media (max-width: 1024px) {
  .circularity-layout { grid-template-columns: 1fr; }
  .circularity-concepts { justify-content: flex-start; }
}

@media (max-width: 980px) {
  .hero .container,
  .materials-layout,
  .modularity-layout {
    grid-template-columns: 1fr;
  }

  .hero-visual { order: -1; }
  .materials-copy { order: -1; }

  .tab-panel { grid-template-columns: 1fr; }
  .tab-panel-decor { display: none; }

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

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

@media (max-width: 700px) {
  .nav-links { display: none; }
  .site-nav .wrap { height: 64px; }
  .brand { font-size: 13px; }

  .hero { padding: var(--space-6) 0 var(--space-6); }
  .section { padding: var(--space-7) 0; }

  .tab-list { grid-template-columns: 1fr; }
  .tab-btn { border-left: none; border-top: 1px solid var(--color-border); }
  .tab-btn:first-child { border-top: none; }

  .factor-diagram {
    grid-template-columns: 1fr;
    grid-template-rows: none;
    gap: var(--space-4);
    min-height: 0;
  }
  .factor-lines { display: none; }
  .factor-diagram .fd-center {
    grid-column: 1 / 2;
    grid-row: auto;
    order: -1;
    max-width: 220px;
    margin: 0 auto var(--space-3);
  }
  .factor-performance, .factor-safety, .factor-durability,
  .factor-environmental, .factor-manufacturability {
    grid-column: 1 / 2;
    grid-row: auto;
    align-self: auto;
  }

  .modularity-steps { grid-template-columns: 1fr 1fr; gap: var(--space-4); }

  .circularity-concepts { flex-wrap: wrap; }

  .cta-layout { flex-direction: column; align-items: flex-start; }
  .cta-actions { width: 100%; }
  .cta-actions .btn { flex: 1; }

  .footer-top { grid-template-columns: 1fr; gap: var(--space-5); }
}

@media (max-width: 480px) {
  :root { --space-5: 18px; }
  .container { padding: 0 16px; }
  .site-nav .wrap { flex-wrap: wrap; height: auto; padding: 10px 16px; gap: 8px; }
  .btn { padding: 10px 14px; font-size: 12.5px; }
  .hero-concepts { flex-wrap: wrap; row-gap: var(--space-2); }
  .modularity-steps { grid-template-columns: 1fr; }
  .tab-panel { padding: var(--space-5) var(--space-4); }
}