:root {
  color-scheme: light dark;
  --page: #f3f6f7;
  --surface: #e8eef0;
  --surface-strong: #dce6e9;
  --text: #172229;
  --muted: #52636d;
  --line: #c9d5d9;
  --accent: #1f6074;
  --accent-hover: #194f60;
  --on-accent: #f7fbfc;
  --focus: #217790;
  --radius: 14px;
  --shadow: 0 22px 55px rgb(32 65 76 / 0.12);
  --shell: 1180px;
  font-family:
    "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans CJK SC",
    system-ui, sans-serif;
  font-synthesis: none;
}

@media (prefers-color-scheme: dark) {
  :root {
    --page: #10171c;
    --surface: #172229;
    --surface-strong: #1d2b33;
    --text: #eef3f5;
    --muted: #acbbc3;
    --line: #34454e;
    --accent: #79b7ca;
    --accent-hover: #90c8d8;
    --on-accent: #0d171c;
    --focus: #8ecbdd;
    --shadow: 0 24px 64px rgb(0 0 0 / 0.28);
  }
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--page);
  color: var(--text);
  font-size: 16px;
  line-height: 1.75;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

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

a {
  color: inherit;
  text-underline-offset: 0.24em;
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 4px;
}

.skip-link {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 10;
  padding: 10px 14px;
  border-radius: var(--radius);
  background: var(--accent);
  color: var(--on-accent);
  font-weight: 700;
  transform: translateY(-160%);
}

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

.shell {
  width: min(calc(100% - 48px), var(--shell));
  margin-inline: auto;
}

.site-header {
  position: relative;
  z-index: 2;
  border-bottom: 1px solid var(--line);
  background: color-mix(in srgb, var(--page) 92%, transparent);
}

.header-inner {
  min-height: 72px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 32px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  color: var(--text);
  font-size: 17px;
  font-weight: 780;
  letter-spacing: -0.02em;
  text-decoration: none;
  white-space: nowrap;
}

.brand-mark {
  width: 36px;
  height: 36px;
  display: grid;
  place-items: center;
  border-radius: var(--radius);
  background: var(--accent);
  color: var(--on-accent);
  font-size: 17px;
  font-weight: 800;
}

nav {
  display: flex;
  align-items: center;
  gap: 28px;
  white-space: nowrap;
}

nav a {
  color: var(--muted);
  font-size: 14px;
  font-weight: 650;
  text-decoration: none;
}

nav a:hover {
  color: var(--accent);
}

.hero {
  min-height: calc(100dvh - 72px);
  display: grid;
  grid-template-columns: minmax(0, 0.88fr) minmax(460px, 1.12fr);
  align-items: center;
  gap: clamp(42px, 7vw, 96px);
  padding-block: clamp(48px, 8vh, 88px);
}

.hero-copy {
  max-width: 580px;
}

.eyebrow {
  margin: 0 0 16px;
  color: var(--accent);
  font-size: 13px;
  font-weight: 760;
  letter-spacing: 0.16em;
}

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

h1 {
  margin-bottom: 24px;
  font-size: clamp(46px, 6vw, 76px);
  line-height: 1.06;
  letter-spacing: -0.065em;
  font-weight: 820;
  text-wrap: balance;
}

.hero-lead {
  max-width: 23em;
  margin-bottom: 34px;
  color: var(--muted);
  font-size: clamp(18px, 2vw, 21px);
  line-height: 1.72;
}

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

.button {
  min-height: 48px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 11px 19px;
  border: 1px solid transparent;
  border-radius: var(--radius);
  font-size: 15px;
  font-weight: 760;
  line-height: 1;
  text-decoration: none;
  white-space: nowrap;
  transition:
    transform 160ms ease,
    background-color 160ms ease,
    border-color 160ms ease;
}

.button:hover {
  transform: translateY(-1px);
}

.button:active {
  transform: translateY(1px);
}

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

.button-primary:hover {
  background: var(--accent-hover);
}

.button-secondary {
  border-color: var(--line);
  background: var(--surface);
  color: var(--text);
}

.button-secondary:hover {
  border-color: var(--accent);
}

.hero-visual,
.article-image {
  margin: 0;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
}

.hero-visual {
  box-shadow: var(--shadow);
}

.hero-visual img {
  width: 100%;
  aspect-ratio: 16 / 10;
  object-fit: cover;
}

.section {
  padding-block: clamp(76px, 10vw, 132px);
}

.section + .section {
  border-top: 1px solid var(--line);
}

.section-heading {
  max-width: 690px;
  margin-bottom: 48px;
}

h2 {
  margin-bottom: 18px;
  font-size: clamp(32px, 4.4vw, 52px);
  line-height: 1.16;
  letter-spacing: -0.048em;
  font-weight: 790;
  text-wrap: balance;
}

h3 {
  margin-bottom: 8px;
  font-size: 19px;
  line-height: 1.35;
}

.section-heading p,
.article-copy > p,
.tool-intro p,
.about-copy p,
.content-notice p {
  color: var(--muted);
  font-size: 17px;
  max-width: 63ch;
}

.dimension-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1.2fr;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.dimension-grid article {
  min-height: 174px;
  padding: 28px 28px 28px 0;
}

.dimension-grid article + article {
  padding-left: 28px;
  border-left: 1px solid var(--line);
}

.dimension-grid p {
  margin-bottom: 0;
  color: var(--muted);
  font-size: 14px;
}

.article-split {
  display: grid;
  grid-template-columns: minmax(0, 1.06fr) minmax(320px, 0.94fr);
  align-items: center;
  gap: clamp(48px, 8vw, 112px);
}

.article-split-reverse {
  grid-template-columns: minmax(320px, 0.94fr) minmax(0, 1.06fr);
}

.article-image img {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
}

.article-copy {
  max-width: 560px;
}

.compact-list,
.tool-list,
.site-facts {
  margin: 32px 0 0;
}

.compact-list > div {
  display: grid;
  grid-template-columns: 86px 1fr;
  gap: 16px;
  padding-block: 16px;
  border-top: 1px solid var(--line);
}

dt {
  font-weight: 760;
}

dd {
  margin: 0;
  color: var(--muted);
}

.check-list {
  margin: 30px 0 0;
  padding: 0;
  list-style: none;
}

.check-list li {
  position: relative;
  padding-left: 24px;
  color: var(--muted);
}

.check-list li + li {
  margin-top: 14px;
}

.check-list li::before {
  content: "";
  position: absolute;
  top: 0.78em;
  left: 0;
  width: 9px;
  height: 2px;
  border-radius: var(--radius);
  background: var(--accent);
}

.tool-guide {
  display: grid;
  grid-template-columns: minmax(0, 0.86fr) minmax(420px, 1.14fr);
  align-items: start;
  gap: clamp(48px, 9vw, 128px);
}

.tool-list {
  display: grid;
  gap: 12px;
}

.tool-list > div {
  display: grid;
  grid-template-columns: 128px 1fr;
  gap: 24px;
  padding: 22px;
  border-radius: var(--radius);
  background: var(--surface);
}

.content-notice {
  display: grid;
  grid-template-columns: minmax(200px, 0.55fr) minmax(0, 1.45fr);
  align-items: start;
  gap: clamp(32px, 8vw, 112px);
}

.content-notice h2 {
  font-size: clamp(27px, 3vw, 38px);
}

.content-notice p {
  margin-bottom: 0;
}

.about {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(360px, 0.9fr);
  align-items: start;
  gap: clamp(48px, 9vw, 128px);
}

.about-copy p + p {
  margin-top: 22px;
}

.site-facts {
  padding: 26px;
  border-radius: var(--radius);
  background: var(--surface);
}

.site-facts > div {
  display: grid;
  grid-template-columns: 100px 1fr;
  gap: 18px;
}

.site-facts > div + div {
  margin-top: 22px;
}

.site-facts dt,
.site-facts dd {
  font-size: 14px;
}

.site-footer {
  border-top: 1px solid var(--line);
}

.footer-inner {
  min-height: 116px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding-block: 28px;
  color: var(--muted);
  font-size: 13px;
  text-align: center;
}

.footer-inner p {
  margin-bottom: 0;
}

.footer-links {
  display: flex;
  align-items: center;
  gap: 24px;
}

.footer-links a:hover {
  color: var(--accent);
}

@media (max-width: 900px) {
  .hero,
  .article-split,
  .article-split-reverse,
  .tool-guide,
  .content-notice,
  .about {
    grid-template-columns: 1fr;
  }

  .hero {
    min-height: auto;
  }

  .hero-copy,
  .article-copy,
  .tool-intro,
  .about-copy {
    max-width: 680px;
  }

  .article-split-reverse .article-copy {
    order: 2;
  }

  .article-split-reverse .article-image {
    order: 1;
  }

  .dimension-grid {
    grid-template-columns: 1fr 1fr;
  }

  .dimension-grid article {
    min-height: 150px;
    padding: 24px;
  }

  .dimension-grid article:nth-child(odd) {
    padding-left: 0;
    border-left: 0;
  }

  .dimension-grid article:nth-child(n + 3) {
    border-top: 1px solid var(--line);
  }
}

@media (max-width: 680px) {
  .shell {
    width: min(calc(100% - 32px), var(--shell));
  }

  .header-inner {
    min-height: 64px;
  }

  nav {
    gap: 16px;
  }

  nav a:first-child {
    display: none;
  }

  .brand {
    font-size: 15px;
  }

  .brand-mark {
    width: 32px;
    height: 32px;
    font-size: 15px;
  }

  .hero {
    gap: 38px;
    padding-block: 48px 64px;
  }

  h1 {
    font-size: clamp(43px, 13vw, 58px);
    letter-spacing: -0.055em;
  }

  .hero-lead {
    font-size: 17px;
  }

  .hero-actions,
  .button {
    width: 100%;
  }

  .section {
    padding-block: 72px;
  }

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

  .dimension-grid {
    grid-template-columns: 1fr;
  }

  .dimension-grid article {
    min-height: auto;
    padding: 22px 0;
    border-left: 0;
  }

  .dimension-grid article + article,
  .dimension-grid article:nth-child(n + 3) {
    border-top: 1px solid var(--line);
  }

  .tool-list > div,
  .site-facts > div {
    grid-template-columns: 1fr;
    gap: 6px;
  }

  .footer-inner,
  .footer-links {
    flex-direction: column;
    justify-content: center;
    gap: 8px;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
  }
}