:root {
  --ink: #10231f;
  --text: #253d38;
  --muted: #647872;
  --line: #dce8e4;
  --soft-line: #edf3f1;
  --surface: #f7faf8;
  --surface-strong: #eef7f4;
  --white: #ffffff;
  --teal: #087b67;
  --teal-dark: #075f52;
  --teal-soft: #d9f1eb;
  --mint: #9ddbcf;
  --graphite: #2f3c39;
  --shadow: 0 20px 50px rgba(16, 35, 31, 0.12);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--white);
  color: var(--text);
  font-family:
    -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Noto Sans CJK SC",
    sans-serif;
  line-height: 1.6;
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  min-height: 76px;
  padding: 14px clamp(20px, 5vw, 72px);
  border-bottom: 1px solid rgba(220, 232, 228, 0.88);
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(16px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  min-width: max-content;
}

.brand-mark {
  display: grid;
  width: 42px;
  height: 42px;
  place-items: center;
  border-radius: 8px;
  background: var(--teal);
  color: var(--white);
  font-weight: 800;
}

.brand strong,
.brand small {
  display: block;
}

.brand strong {
  color: var(--ink);
  font-size: 17px;
  letter-spacing: 0;
}

.brand small {
  color: var(--muted);
  font-size: 10px;
  letter-spacing: 1.4px;
}

.site-nav {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: clamp(12px, 2vw, 28px);
  color: var(--graphite);
  font-size: 14px;
}

.site-nav a {
  padding: 8px 0;
}

.site-nav a:hover,
.site-nav a:focus-visible {
  color: var(--teal);
}

.header-actions,
.hero-actions {
  display: flex;
  align-items: center;
  gap: 10px;
}

button,
.primary-button,
.secondary-button {
  border: 0;
  border-radius: 8px;
  font: inherit;
  font-weight: 700;
  cursor: pointer;
}

.primary-button,
.secondary-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 18px;
}

.primary-button {
  background: var(--teal);
  color: var(--white);
}

.primary-button:hover,
.primary-button:focus-visible {
  background: var(--teal-dark);
}

.primary-button.compact {
  min-height: 38px;
  padding: 0 14px;
  font-size: 14px;
}

.secondary-button {
  border: 1px solid var(--line);
  background: var(--white);
  color: var(--ink);
}

.secondary-button:hover,
.secondary-button:focus-visible {
  border-color: var(--teal);
  color: var(--teal);
}

.section-band {
  background: var(--surface);
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.08fr) minmax(360px, 0.92fr);
  gap: clamp(28px, 5vw, 72px);
  min-height: calc(100vh - 76px);
  padding: clamp(56px, 8vw, 110px) clamp(20px, 5vw, 72px);
  align-items: center;
}

.hero-copy {
  max-width: 760px;
}

.eyebrow {
  margin: 0 0 12px;
  color: var(--teal);
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  margin-bottom: 18px;
  color: var(--ink);
  font-size: clamp(42px, 6vw, 76px);
  line-height: 1.05;
  letter-spacing: 0;
}

h2 {
  margin-bottom: 12px;
  color: var(--ink);
  font-size: clamp(30px, 4vw, 48px);
  line-height: 1.15;
  letter-spacing: 0;
}

h3 {
  color: var(--ink);
  font-size: 24px;
  line-height: 1.25;
}

.hero-lead {
  max-width: 660px;
  margin-bottom: 14px;
  color: var(--ink);
  font-size: clamp(22px, 2.4vw, 30px);
  line-height: 1.35;
  font-weight: 700;
}

.hero-text {
  max-width: 680px;
  margin-bottom: 28px;
  color: var(--muted);
  font-size: 17px;
}

.hero-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin: 34px 0 0;
}

.hero-facts div {
  min-width: 0;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--white);
}

.hero-facts dt {
  margin-bottom: 6px;
  color: var(--muted);
  font-size: 13px;
}

.hero-facts dd {
  margin: 0;
  color: var(--ink);
  font-weight: 700;
}

.hero-visual {
  align-self: stretch;
  display: grid;
  min-height: 500px;
  align-content: center;
  padding: clamp(18px, 3vw, 32px);
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--white);
  box-shadow: var(--shadow);
}

.materials-diagram {
  display: block;
  width: 100%;
  height: auto;
}

.materials-diagram text {
  fill: var(--ink);
  font-family:
    -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Noto Sans CJK SC",
    sans-serif;
  font-size: 17px;
  font-weight: 800;
}

.separator-group text,
.anode-zone > text,
.materials-diagram > text {
  font-size: 18px;
}

.electrolyte-space path {
  fill: none;
  stroke: var(--mint);
  stroke-width: 2;
  stroke-dasharray: 7 9;
}

.electrolyte-space text {
  fill: var(--muted);
  font-size: 14px;
  font-weight: 700;
}

.particle text {
  fill: var(--ink);
  font-size: 18px;
}

.small-particles .core {
  fill: #738782;
  opacity: 0.62;
}

.small-particles .shell {
  fill: none;
  stroke: var(--teal);
  stroke-width: 4;
  opacity: 0.85;
}

.callout path {
  fill: none;
  stroke: var(--teal);
  stroke-width: 2;
  marker-end: url("#arrow");
}

.callout text {
  fill: var(--teal-dark);
  font-size: 15px;
}

.visual-caption {
  margin: 16px 0 0;
  color: var(--muted);
  font-size: 14px;
}

.section {
  padding: clamp(64px, 8vw, 108px) clamp(20px, 5vw, 72px);
}

.section-heading {
  max-width: 820px;
  margin-bottom: 34px;
}

.section-heading p:not(.eyebrow) {
  color: var(--muted);
  font-size: 17px;
}

.compact-heading {
  margin-bottom: 0;
}

.product-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px;
}

.product-card {
  min-height: 100%;
  padding: clamp(24px, 4vw, 38px);
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--white);
}

.product-card:first-child {
  background: var(--surface-strong);
}

.product-kicker {
  margin-bottom: 16px;
  color: var(--teal);
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.product-card p {
  color: var(--text);
  font-size: 17px;
}

.product-card ul {
  display: grid;
  gap: 10px;
  margin: 22px 0 0;
  padding: 0;
  list-style: none;
}

.product-card li {
  position: relative;
  padding-left: 18px;
  color: var(--muted);
}

.product-card li::before {
  position: absolute;
  top: 0.68em;
  left: 0;
  width: 7px;
  height: 7px;
  border-radius: 999px;
  background: var(--teal);
  content: "";
}

.split-section {
  display: grid;
  grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.1fr);
  gap: clamp(28px, 5vw, 64px);
  align-items: start;
  background: var(--surface);
}

.technology-panel {
  display: grid;
  gap: 14px;
}

.tech-item {
  display: grid;
  grid-template-columns: 56px minmax(0, 1fr);
  column-gap: 18px;
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--white);
}

.tech-item span {
  grid-row: span 2;
  display: grid;
  width: 48px;
  height: 48px;
  place-items: center;
  border-radius: 8px;
  background: var(--teal-soft);
  color: var(--teal-dark);
  font-weight: 900;
}

.tech-item h3 {
  margin-bottom: 6px;
  font-size: 20px;
}

.tech-item p {
  margin-bottom: 0;
  color: var(--muted);
}

.validation-section {
  background: var(--white);
}

.timeline {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
  margin: 0;
  padding: 0;
  list-style: none;
  counter-reset: step;
}

.timeline li {
  position: relative;
  min-height: 230px;
  padding: 62px 22px 22px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
  color: var(--muted);
}

.timeline li::before {
  position: absolute;
  top: 20px;
  left: 22px;
  color: var(--teal);
  content: "0" counter(step);
  counter-increment: step;
  font-weight: 900;
}

.timeline span {
  display: block;
  margin-bottom: 10px;
  color: var(--ink);
  font-size: 18px;
  font-weight: 800;
}

.site-footer {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(300px, 420px);
  gap: 32px;
  padding: clamp(56px, 7vw, 86px) clamp(20px, 5vw, 72px);
  background: var(--surface);
}

.site-footer h2 {
  font-size: clamp(28px, 3vw, 40px);
}

.contact-card {
  align-self: start;
  padding: 26px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--white);
}

.contact-card p {
  margin-bottom: 12px;
  color: var(--muted);
}

.phone {
  display: block;
  margin-bottom: 16px;
  color: var(--teal);
  font-size: 32px;
  font-weight: 900;
  line-height: 1.1;
}

@media (max-width: 1080px) {
  .site-header {
    flex-wrap: wrap;
  }

  .site-nav {
    order: 3;
    width: 100%;
    justify-content: flex-start;
    overflow-x: auto;
  }

  .hero,
  .split-section,
  .site-footer {
    grid-template-columns: 1fr;
  }

  .hero {
    min-height: auto;
  }

  .hero-visual {
    min-height: 420px;
  }

  .timeline {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 720px) {
  .site-header {
    padding: 12px 16px;
  }

  .header-actions {
    width: 100%;
    justify-content: space-between;
  }

  .hero,
  .section,
  .site-footer {
    padding-right: 16px;
    padding-left: 16px;
  }

  .hero-actions,
  .hero-facts,
  .product-grid,
  .timeline {
    grid-template-columns: 1fr;
  }

  .hero-actions {
    display: grid;
  }

  .product-grid,
  .hero-facts {
    display: grid;
  }

  .hero-visual {
    min-height: 360px;
    padding: 18px;
  }

  .tech-item {
    grid-template-columns: 1fr;
  }

  .tech-item span {
    margin-bottom: 14px;
  }

  .timeline li {
    min-height: 0;
  }

  .phone {
    font-size: 28px;
  }
}