:root {
  color-scheme: light;
  --app: #f5f8fb;
  --surface: #ffffff;
  --ink: #071520;
  --muted: #526779;
  --line: #d7e1e8;
  --accent: #18b6d9;
  --accent-hover: #0c8eaf;
  --accent-pressed: #08718c;
  --accent-soft: #e2f7fb;
  --warning: #a85f00;
  --warning-soft: #fff3d6;
  --success: #11785b;
  --measure: 72ch;
  font-family: "Segoe UI", "Helvetica Neue", Arial, sans-serif;
  font-synthesis: none;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scrollbar-color: var(--muted) var(--app);
}

body {
  margin: 0;
  background: var(--app);
  color: var(--ink);
  font-size: 16px;
  line-height: 1.65;
  text-rendering: optimizeLegibility;
}

::selection {
  background: var(--accent);
  color: var(--ink);
}

a {
  color: var(--accent-pressed);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.2em;
}

a:hover {
  color: var(--accent-pressed);
  text-decoration-thickness: 2px;
}

a:focus-visible,
.button:focus-visible {
  outline: 3px solid var(--accent-pressed);
  outline-offset: 4px;
  border-radius: 4px;
}

.skip-link {
  position: fixed;
  left: 18px;
  top: 14px;
  z-index: 10;
  padding: 10px 14px;
  background: var(--surface);
  color: var(--ink);
  transform: translateY(-160%);
  transition: transform 160ms ease-out;
}

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

.site-header {
  background: var(--ink);
  color: var(--surface);
}

.header-inner {
  width: min(1120px, calc(100% - 48px));
  min-height: 104px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 32px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 14px;
  color: var(--surface);
  text-decoration: none;
}

.brand:hover {
  color: var(--surface);
  text-decoration: none;
}

.brand-mark {
  flex: 0 0 auto;
  overflow: visible;
}

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

.brand strong {
  font-size: 1.18rem;
  letter-spacing: -0.015em;
}

.brand small {
  color: #a9bbc8;
  font-size: 0.78rem;
}

nav {
  display: flex;
  align-items: center;
  gap: 24px;
}

nav a {
  position: relative;
  color: #c5d3dc;
  font-size: 0.9rem;
  font-weight: 600;
  text-decoration: none;
}

nav a:hover,
nav a[aria-current="page"] {
  color: var(--surface);
}

nav a[aria-current="page"]::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -10px;
  height: 2px;
  background: var(--accent);
}

main {
  width: min(1120px, calc(100% - 48px));
  margin: 0 auto;
}

.intro {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1.45fr) minmax(320px, 0.75fr);
  gap: clamp(44px, 7vw, 96px);
  align-items: end;
  padding: clamp(64px, 9vw, 108px) 0 clamp(56px, 8vw, 92px);
}

.intro::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 1px;
  background: linear-gradient(90deg, var(--accent) 0 20%, var(--line) 20% 100%);
  transform-origin: left;
}

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

h1 {
  max-width: 17ch;
  margin-bottom: 22px;
  font-size: clamp(2.55rem, 5.6vw, 5.2rem);
  line-height: 0.98;
  letter-spacing: -0.035em;
  text-wrap: balance;
}

.lede {
  max-width: 62ch;
  margin-bottom: 18px;
  color: var(--muted);
  font-size: clamp(1.05rem, 1.7vw, 1.24rem);
  line-height: 1.55;
}

.effective-date {
  color: var(--muted);
  font-size: 0.84rem;
  font-variant-numeric: tabular-nums;
}

.boundary {
  background: var(--surface);
  border-top: 3px solid var(--accent);
  box-shadow: 0 12px 34px rgba(7, 21, 32, 0.08);
}

.boundary div {
  display: flex;
  justify-content: space-between;
  gap: 24px;
  padding: 14px 18px;
  border-bottom: 1px solid var(--line);
}

.boundary div:last-child {
  border-bottom: 0;
}

.boundary span {
  color: var(--muted);
}

.boundary strong {
  text-align: right;
}

.reading-layout {
  display: grid;
  grid-template-columns: minmax(0, var(--measure)) 220px;
  justify-content: space-between;
  gap: clamp(48px, 8vw, 110px);
  padding: 72px 0 110px;
}

article section {
  padding: 0 0 56px;
  margin: 0 0 56px;
  border-bottom: 1px solid var(--line);
  scroll-margin-top: 24px;
}

article section:last-child {
  padding-bottom: 0;
  margin-bottom: 0;
  border-bottom: 0;
}

h2 {
  margin-bottom: 18px;
  font-size: clamp(1.65rem, 3vw, 2.35rem);
  line-height: 1.15;
  letter-spacing: -0.025em;
}

h3 {
  margin-bottom: 12px;
  font-size: 1rem;
}

article p,
article li {
  color: #344b5d;
}

article strong {
  color: var(--ink);
}

.evidence-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
  margin-top: 34px;
}

ul {
  padding-left: 1.2rem;
}

li + li {
  margin-top: 8px;
}

.contents {
  position: sticky;
  top: 28px;
  align-self: start;
  padding-left: 20px;
  border-left: 1px solid var(--line);
}

.contents strong,
.contents a {
  display: block;
}

.contents strong {
  margin-bottom: 12px;
  font-size: 0.84rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.contents a {
  padding: 5px 0;
  color: var(--muted);
  font-size: 0.9rem;
  text-decoration: none;
}

.contents a:hover {
  color: var(--accent-pressed);
}

address {
  color: var(--muted);
  font-style: normal;
}

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

.button {
  display: inline-flex;
  min-height: 44px;
  align-items: center;
  justify-content: center;
  padding: 10px 18px;
  border-radius: 8px;
  font-weight: 700;
  text-decoration: none;
}

.button:hover {
  text-decoration: none;
}

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

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

.button.primary:active {
  background: var(--accent-pressed);
  color: var(--surface);
}

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

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

.support-steps {
  padding: 0;
  margin: 30px 0 0;
  list-style: none;
  counter-reset: support-step;
}

.support-steps li {
  counter-increment: support-step;
  display: grid;
  grid-template-columns: 38px minmax(0, 1fr);
  gap: 2px 16px;
  padding: 20px 0;
  border-top: 1px solid var(--line);
}

.support-steps li::before {
  content: counter(support-step, decimal-leading-zero);
  grid-row: 1 / span 2;
  color: var(--accent-pressed);
  font-family: "Cascadia Mono", Consolas, monospace;
  font-size: 0.82rem;
  font-variant-numeric: tabular-nums;
}

.support-steps span {
  margin-top: 4px;
}

code {
  padding: 2px 5px;
  background: var(--accent-soft);
  color: var(--ink);
  font-family: "Cascadia Mono", Consolas, monospace;
  font-size: 0.9em;
}

.attention-note {
  margin-top: 28px;
  padding: 20px 22px;
  background: var(--warning-soft);
  color: #6e4100;
  border: 1px solid #e5b35e;
  border-radius: 12px;
}

.attention-note p {
  margin: 6px 0 0;
  color: #6e4100;
}

footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 30px max(24px, calc((100% - 1120px) / 2));
  background: var(--ink);
  color: #c5d3dc;
}

footer p {
  margin: 0;
}

footer a {
  color: var(--surface);
  white-space: nowrap;
}

@media (prefers-reduced-motion: no-preference) {
  .intro::after {
    animation: signal-arrive 520ms cubic-bezier(0.16, 1, 0.3, 1) both;
  }

  .brand-endpoint {
    transform-box: fill-box;
    transform-origin: center;
    animation: endpoint-confirm 600ms 180ms cubic-bezier(0.16, 1, 0.3, 1) both;
  }
}

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

@keyframes signal-arrive {
  from { transform: scaleX(0.72); opacity: 0.65; }
  to { transform: scaleX(1); opacity: 1; }
}

@keyframes endpoint-confirm {
  0% { transform: scale(0.86); }
  58% { transform: scale(1.16); }
  100% { transform: scale(1); }
}

@media (max-width: 820px) {
  .intro {
    grid-template-columns: 1fr;
    align-items: start;
  }

  .reading-layout {
    grid-template-columns: 1fr;
    padding-top: 56px;
  }

  .contents {
    display: none;
  }
}

@media (max-width: 620px) {
  .header-inner,
  main {
    width: min(100% - 32px, 1120px);
  }

  .header-inner {
    min-height: 92px;
  }

  .brand small {
    display: none;
  }

  nav {
    gap: 14px;
  }

  .intro {
    gap: 38px;
    padding: 54px 0 48px;
  }

  h1 {
    font-size: clamp(2.35rem, 13vw, 3.6rem);
  }

  .boundary div {
    align-items: baseline;
  }

  .reading-layout {
    padding-bottom: 72px;
  }

  .evidence-grid {
    grid-template-columns: 1fr;
    gap: 24px;
  }

  footer {
    align-items: flex-start;
    flex-direction: column;
  }
}

@media print {
  .site-header,
  .skip-link,
  .contents,
  footer,
  .actions {
    display: none;
  }

  body,
  main {
    background: #fff;
    color: #000;
  }

  main {
    width: 100%;
  }

  .intro,
  .reading-layout {
    display: block;
    padding: 24px 0;
  }

  .boundary {
    margin-top: 24px;
    box-shadow: none;
  }
}