:root {
  --bg: #f6f7f5;
  --ink: #17201b;
  --muted: #68716c;
  --line: #d8ddd7;
  --panel: #ffffff;
  --accent: #0f766e;
  --accent-dark: #0d4f4c;
  --gold: #b8862d;
  --graphite: #2d3230;
  --radius: 8px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family:
    Inter, "Segoe UI", "PingFang SC", "Microsoft YaHei", Arial, 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;
  padding: 14px clamp(20px, 5vw, 72px);
  border-bottom: 1px solid rgba(216, 221, 215, 0.82);
  background: rgba(246, 247, 245, 0.92);
  backdrop-filter: blur(16px);
}

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

.brand-mark {
  display: grid;
  width: 42px;
  height: 42px;
  place-items: center;
  border-radius: 50%;
  background: var(--graphite);
  color: #f7f5ee;
  font-weight: 800;
}

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

.brand small {
  color: var(--muted);
  font-size: 12px;
}

nav {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  justify-content: flex-end;
}

nav a {
  padding: 8px 10px;
  color: #39413d;
  font-size: 14px;
}

.hero {
  min-height: calc(100vh - 74px);
  display: grid;
  align-items: center;
  padding: clamp(56px, 8vw, 96px) clamp(20px, 5vw, 72px);
  background:
    linear-gradient(90deg, rgba(12, 21, 18, 0.74), rgba(12, 21, 18, 0.32) 48%, rgba(12, 21, 18, 0.08)),
    url("assets/optics-hero.png") center / cover no-repeat;
  color: #fffdf7;
}

.hero-copy {
  width: min(720px, 100%);
}

.eyebrow {
  margin: 0 0 10px;
  color: var(--gold);
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  overflow-wrap: anywhere;
}

h1 {
  max-width: 12em;
  margin: 0;
  font-size: clamp(42px, 7vw, 82px);
  line-height: 1.05;
  letter-spacing: 0;
}

h2 {
  margin: 0;
  font-size: clamp(28px, 4vw, 48px);
  line-height: 1.12;
  letter-spacing: 0;
}

h3 {
  margin: 0 0 8px;
  font-size: 21px;
  line-height: 1.25;
}

.lead {
  width: min(620px, 100%);
  margin: 22px 0 0;
  color: rgba(255, 253, 247, 0.86);
  font-size: clamp(17px, 2vw, 21px);
}

.hero-actions,
.contact-section {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
}

.hero-actions {
  margin-top: 30px;
}

.button {
  display: inline-flex;
  min-height: 44px;
  align-items: center;
  justify-content: center;
  border: 1px solid transparent;
  border-radius: var(--radius);
  padding: 10px 18px;
  font-weight: 800;
}

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

.button.secondary {
  border-color: rgba(255, 255, 255, 0.58);
  color: #fff;
}

.section {
  padding: clamp(56px, 8vw, 96px) clamp(20px, 5vw, 72px);
}

.intro-band {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 1px;
  padding-top: 0;
  padding-bottom: 0;
  background: var(--line);
}

.metric {
  min-height: 132px;
  padding: 28px;
  background: #fcfcfa;
}

.metric strong {
  display: block;
  color: var(--accent-dark);
  font-size: clamp(22px, 2.4vw, 34px);
  line-height: 1.1;
}

.metric span,
.section-heading p,
.product-card p,
.design-detail-grid p,
.design-list p,
.contact-section p,
.note {
  color: var(--muted);
}

.section-heading {
  width: min(760px, 100%);
  margin-bottom: 30px;
}

.section-heading p {
  margin: 12px 0 0;
}

.product-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
}

.product-card {
  min-height: 250px;
  padding: 28px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
}

.product-kicker {
  margin: 0 0 8px;
  color: var(--gold);
  font-size: clamp(15px, 1.5vw, 18px);
  font-weight: 800;
}

.product-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 18px 0 0;
  padding: 0;
  list-style: none;
}

.product-tags li {
  border: 1px solid #cbd8d3;
  border-radius: 999px;
  padding: 6px 10px;
  background: #f7faf8;
  color: var(--accent-dark);
  font-size: 13px;
  font-weight: 800;
}

.icon {
  display: inline-grid;
  width: 64px;
  height: 64px;
  margin-bottom: 20px;
  place-items: center;
  border: 1px solid #cbd8d3;
  border-radius: 50%;
  color: var(--accent-dark);
  background: #fbfdfb;
}

.product-icon svg {
  width: 40px;
  height: 40px;
  fill: none;
  stroke: currentColor;
  stroke-width: 2.5;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.product-icon.indoor {
  color: #0f766e;
}

.product-icon.outdoor {
  color: #0d5f73;
}

.product-icon.automotive {
  color: #0d4f4c;
}

.design-section {
  background: #e9ede8;
}

.design-detail-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 16px;
  margin-bottom: 42px;
}

.design-detail-grid article {
  min-height: 260px;
  padding: 24px;
  border: 1px solid #ccd6d0;
  border-radius: var(--radius);
  background: rgba(255, 255, 255, 0.62);
}

.design-kicker {
  margin: 0 0 10px;
  color: var(--gold);
  font-size: 12px;
  font-weight: 800;
  text-transform: uppercase;
}

.design-list {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 36px;
}

.design-list div {
  border-top: 2px solid var(--accent);
  padding-top: 18px;
}

.calculator-section {
  background: #fbfbf8;
}

.calculator {
  display: grid;
  grid-template-columns: minmax(280px, 0.95fr) minmax(320px, 1.05fr);
  gap: 18px;
  align-items: start;
}

.calc-form,
.result-panel,
.ies-panel,
.knowledge-grid article {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
  padding: clamp(20px, 3vw, 30px);
}

.calc-form {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

label {
  display: grid;
  gap: 7px;
  color: #37413c;
  font-size: 14px;
  font-weight: 800;
}

input,
select {
  width: 100%;
  height: 44px;
  border: 1px solid #cfd7d2;
  border-radius: var(--radius);
  background: #fff;
  color: var(--ink);
  font: inherit;
  padding: 0 12px;
}

.field-row {
  display: grid;
  grid-template-columns: 1fr 42px;
  align-items: center;
  gap: 8px;
}

.field-row small {
  color: var(--muted);
}

.result-label {
  margin: 0 0 8px;
  color: var(--gold);
  font-weight: 800;
}

.result-panel h3 {
  margin-bottom: 20px;
  color: var(--accent-dark);
  font-size: clamp(26px, 4vw, 42px);
}

.result-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.result-grid div {
  min-height: 112px;
  padding: 18px;
  background: #f9faf7;
}

.result-grid span,
.result-grid strong {
  display: block;
}

.result-grid span {
  margin-bottom: 8px;
  color: var(--muted);
  font-size: 13px;
}

.result-grid strong {
  color: var(--ink);
  font-size: clamp(18px, 2vw, 24px);
  line-height: 1.25;
}

.note {
  margin: 18px 0 0;
}

.ies-panel {
  display: grid;
  grid-template-columns: minmax(240px, 0.95fr) minmax(220px, 0.75fr) minmax(300px, 1.3fr);
  gap: 18px;
  margin-top: 18px;
  align-items: start;
}

.ies-intro p {
  margin: 10px 0 0;
  color: var(--muted);
}

.file-drop {
  min-height: 132px;
  place-content: center;
  border: 1px dashed #aebbb6;
  border-radius: var(--radius);
  background: #f7faf8;
  padding: 18px;
  text-align: center;
}

.file-drop span {
  color: var(--accent-dark);
  font-size: 18px;
}

.file-drop input {
  height: auto;
  margin-top: 12px;
  border: 0;
  padding: 0;
}

.ies-results {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  border: 1px solid var(--line);
  background: var(--line);
}

.ies-results div {
  min-height: 86px;
  padding: 14px;
  background: #f9faf7;
}

.ies-results span,
.ies-results strong {
  display: block;
}

.ies-results span,
.type-bars span {
  color: var(--muted);
  font-size: 13px;
}

.ies-results strong {
  margin-top: 6px;
  color: var(--ink);
  font-size: 20px;
}

.type-bars {
  grid-column: 1 / -1;
  display: grid;
  gap: 10px;
}

.type-bars div {
  display: grid;
  grid-template-columns: 72px 1fr 48px;
  gap: 10px;
  align-items: center;
}

meter {
  width: 100%;
  height: 14px;
}

.education-section {
  background: #f1f4f1;
}

.knowledge-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
}

.knowledge-grid article {
  min-height: 230px;
}

.knowledge-grid p {
  color: var(--muted);
}

.contact-section {
  justify-content: space-between;
  background: var(--graphite);
  color: #fffdf7;
}

.contact-section div {
  width: min(680px, 100%);
}

.contact-section p {
  color: rgba(255, 253, 247, 0.76);
}

footer {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 10px;
  padding: 22px clamp(20px, 5vw, 72px);
  color: var(--muted);
  font-size: 13px;
}

@media (max-width: 900px) {
  .site-header,
  .intro-band,
  .product-grid,
  .design-detail-grid,
  .design-list,
  .calculator,
  .ies-panel,
  .knowledge-grid {
    grid-template-columns: 1fr;
  }

  .site-header {
    display: grid;
  }

  nav {
    justify-content: flex-start;
  }

  .hero {
    min-height: 720px;
    background-position: 64% center;
  }
}

@media (max-width: 620px) {
  .calc-form,
  .result-grid,
  .ies-results {
    grid-template-columns: 1fr;
  }

  .hero {
    min-height: 650px;
  }

  h1 {
    font-size: 40px;
  }
}