:root {
  color-scheme: light;
  --ink: #17231f;
  --muted: #5b6863;
  --paper: #f7f8f5;
  --surface: #ffffff;
  --soft: #eef4f1;
  --line: #d9e3df;
  --deep: #0f3028;
  --teal: #1f796f;
  --blue: #315e9a;
  --amber: #e1a33f;
  --coral: #c95d42;
  --shadow: 0 18px 44px rgba(15, 48, 40, 0.14);
  --radius: 8px;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  line-height: 1.65;
}

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

a {
  color: inherit;
}

p,
ul,
ol {
  margin-top: 0;
}

button {
  font: inherit;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: absolute;
  top: 12px;
  left: 12px;
  z-index: 20;
  transform: translateY(-140%);
  padding: 10px 14px;
  background: var(--ink);
  color: #fff;
  border-radius: var(--radius);
}

.skip-link:focus {
  transform: translateY(0);
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(247, 248, 245, 0.94);
  border-bottom: 1px solid rgba(217, 227, 223, 0.9);
  backdrop-filter: blur(16px);
}

.nav {
  width: min(1160px, calc(100% - 32px));
  min-height: 68px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  text-decoration: none;
}

.brand-mark {
  display: inline-grid;
  place-items: center;
  width: 38px;
  height: 38px;
  border-radius: 50%;
  background: var(--deep);
  color: #fff;
  font-size: 0.74rem;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 6px;
  color: #33423c;
  font-size: 0.94rem;
}

.nav-links a {
  min-height: 40px;
  display: inline-flex;
  align-items: center;
  padding: 8px 10px;
  border-radius: var(--radius);
  text-decoration: none;
}

.nav-links a:hover,
.nav-links a:focus-visible {
  background: #e7efeb;
}

.nav-toggle {
  display: none;
  width: 44px;
  height: 44px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fff;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: 4px;
}

.nav-toggle span:not(.sr-only) {
  width: 19px;
  height: 2px;
  background: var(--ink);
}

.hero {
  min-height: min(680px, 74vh);
  position: relative;
  display: grid;
  align-items: center;
  overflow: hidden;
  isolation: isolate;
}

.hero-media {
  position: absolute;
  inset: 0;
  background:
    linear-gradient(90deg, rgba(15, 48, 40, 0.9), rgba(15, 48, 40, 0.7) 44%, rgba(15, 48, 40, 0.12)),
    url("../assets/smart-ring-technology-hero.jpg") center / cover no-repeat;
  z-index: -2;
}

.hero-shade {
  position: absolute;
  inset: auto 0 0 0;
  height: 120px;
  background: linear-gradient(180deg, rgba(247, 248, 245, 0), var(--paper));
  z-index: -1;
}

.container,
.hero-inner {
  width: min(1160px, calc(100% - 32px));
  margin: 0 auto;
}

.hero-inner {
  max-width: 760px;
  margin-left: max(16px, calc((100vw - 1160px) / 2));
  padding: 70px 0 96px;
  color: #fff;
}

.eyebrow,
.section-kicker {
  margin: 0 0 12px;
  color: var(--amber);
  font-size: 0.78rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0;
}

.hero h1 {
  max-width: 760px;
  margin: 0;
  font-size: 5.6rem;
  line-height: 0.96;
  letter-spacing: 0;
}

.hero-copy {
  max-width: 680px;
  margin: 24px 0 0;
  color: rgba(255, 255, 255, 0.91);
  font-size: 1.16rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 30px;
}

.button {
  min-height: 46px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 11px 16px;
  border-radius: var(--radius);
  background: var(--amber);
  color: #17231f;
  font-weight: 800;
  text-decoration: none;
}

.button-secondary {
  background: var(--teal);
  color: #fff;
}

.button-ghost {
  background: rgba(255, 255, 255, 0.12);
  color: #fff;
  border: 1px solid rgba(255, 255, 255, 0.42);
}

.section {
  padding: 78px 0;
}

.section-tight {
  padding: 54px 0;
}

.band-soft {
  background: var(--soft);
}

.band-dark {
  background: var(--deep);
  color: #fff;
}

.intro-grid,
.split,
.method-grid {
  display: grid;
  grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.1fr);
  gap: 42px;
  align-items: start;
}

h2,
h3 {
  line-height: 1.15;
  letter-spacing: 0;
}

h2 {
  margin: 0 0 18px;
  font-size: 2.1rem;
}

h3 {
  margin: 0 0 10px;
  font-size: 1.18rem;
}

.lead {
  color: var(--muted);
  font-size: 1.08rem;
}

.section-head {
  max-width: 720px;
  margin-bottom: 28px;
}

.card-grid {
  display: grid;
  gap: 18px;
}

.card-grid.three {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.card {
  min-height: 260px;
  padding: 24px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: 0 12px 28px rgba(15, 48, 40, 0.08);
}

.card-icon,
.tag {
  display: inline-flex;
  align-items: center;
  min-height: 28px;
  padding: 3px 9px;
  border-radius: 999px;
  background: #e8f0ff;
  color: var(--blue);
  font-size: 0.78rem;
  font-weight: 800;
}

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

.text-link {
  color: var(--teal);
  font-weight: 800;
  text-decoration-thickness: 2px;
  text-underline-offset: 4px;
}

.feature-list {
  display: grid;
  border-top: 1px solid var(--line);
}

.feature-row {
  display: grid;
  grid-template-columns: 220px minmax(0, 1fr);
  gap: 22px;
  padding: 24px 0;
  border-bottom: 1px solid var(--line);
  text-decoration: none;
}

.feature-row span {
  color: var(--muted);
  font-weight: 800;
}

.feature-row strong {
  font-size: 1.12rem;
}

.note-box {
  padding: 22px;
  border-left: 5px solid var(--coral);
  background: #fff;
  border-radius: 0 var(--radius) var(--radius) 0;
}

.article-hero {
  padding: 62px 0 46px;
  background: var(--soft);
}

.article-hero h1 {
  max-width: 860px;
  margin: 0;
  font-size: 3.6rem;
  line-height: 1;
  letter-spacing: 0;
}

.article-hero p:not(.section-kicker) {
  max-width: 760px;
  margin: 18px 0 0;
  color: var(--muted);
  font-size: 1.12rem;
}

.meta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 20px;
}

.article-layout {
  width: min(1160px, calc(100% - 32px));
  margin: 0 auto;
  display: grid;
  grid-template-columns: 250px minmax(0, 1fr);
  gap: 46px;
  padding: 54px 0 82px;
}

.toc {
  position: sticky;
  top: 92px;
  align-self: start;
  display: grid;
  gap: 10px;
  padding: 18px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.toc a {
  color: var(--muted);
  text-decoration: none;
}

.toc a:hover {
  color: var(--teal);
}

.article-content {
  max-width: 820px;
}

.article-content section + section {
  margin-top: 44px;
}

.article-content h2 {
  padding-top: 8px;
}

.article-content p,
.article-content li {
  color: #36443f;
}

.callout {
  margin: 24px 0;
  padding: 18px 20px;
  border: 1px solid #d9e3df;
  border-left: 5px solid var(--teal);
  background: #fff;
  border-radius: 0 var(--radius) var(--radius) 0;
}

.warning {
  border-left-color: var(--coral);
}

.table-wrap {
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fff;
}

table {
  width: 100%;
  border-collapse: collapse;
}

th,
td {
  padding: 14px 15px;
  border-bottom: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}

th {
  background: #eef4f1;
  font-size: 0.86rem;
  text-transform: uppercase;
  letter-spacing: 0;
}

tr:last-child td {
  border-bottom: 0;
}

.source-list a {
  color: var(--teal);
  overflow-wrap: anywhere;
}

.site-footer {
  padding: 46px 0 26px;
  background: #101b18;
  color: #fff;
}

.footer-grid {
  display: grid;
  grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.1fr);
  gap: 34px;
}

.footer-brand .brand-mark {
  background: #fff;
  color: var(--deep);
}

.footer-grid p,
.footer-bottom {
  color: rgba(255, 255, 255, 0.74);
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 16px;
}

.footer-links a {
  color: rgba(255, 255, 255, 0.86);
  text-decoration: none;
}

.footer-bottom {
  margin-top: 28px;
  padding-top: 20px;
  border-top: 1px solid rgba(255, 255, 255, 0.16);
}

@media (max-width: 900px) {
  .nav-toggle {
    display: inline-flex;
  }

  .nav-links {
    position: absolute;
    top: 68px;
    left: 16px;
    right: 16px;
    display: none;
    padding: 12px;
    background: #fff;
    border: 1px solid var(--line);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    flex-direction: column;
    align-items: stretch;
  }

  .nav-links.is-open {
    display: flex;
  }

  .intro-grid,
  .split,
  .method-grid,
  .footer-grid,
  .article-layout {
    grid-template-columns: 1fr;
  }

  .card-grid.three {
    grid-template-columns: 1fr;
  }

  .toc {
    position: static;
  }
}

@media (max-width: 680px) {
  .hero h1 {
    font-size: 3.1rem;
  }

  .hero-copy {
    font-size: 1rem;
  }

  .article-hero h1 {
    font-size: 2.45rem;
  }

  h2 {
    font-size: 1.7rem;
  }

  .feature-row {
    grid-template-columns: 1fr;
    gap: 6px;
  }

  .section {
    padding: 58px 0;
  }
}