:root {
  --color-bg: #fffcf5;
  --color-panel: #f4faf8;
  --color-panel-strong: #e7f5f3;
  --color-border: #cfe1de;
  --color-accent: #00a6b2;
  --color-accent-dark: #007681;
  --color-text: #121716;
  --color-muted: #667371;
  --color-success: #16845b;
  --color-warning: #a96c16;
  --color-error: #c54b43;
  --color-white: #ffffff;
  --color-black: #202625;
  --color-flag-red: #d94a4a;
  --color-flag-blue: #315c9d;
  --color-flag-navy: #263f72;
  --color-flag-yellow: #e7bd45;
  --color-flag-green: #2f805a;
  --color-shadow: color-mix(in srgb, var(--color-text) 11%, transparent);
  --color-accent-soft: color-mix(in srgb, var(--color-accent) 13%, transparent);
  --color-accent-faint: color-mix(in srgb, var(--color-accent) 6%, transparent);
  --color-white-soft: color-mix(in srgb, var(--color-white) 78%, transparent);
  --font-display: Inter, "Noto Sans SC", "Noto Sans JP", "Noto Sans KR", system-ui, sans-serif;
  --font-body: Inter, "Noto Sans SC", "Noto Sans JP", "Noto Sans KR", system-ui, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Consolas, monospace;
  --radius-xs: 8px;
  --radius-sm: 12px;
  --radius-md: 18px;
  --radius-lg: 28px;
  --radius-xl: 38px;
  --radius-pill: 999px;
  --gutter: clamp(16px, 4vw, 32px);
  --page-width: 1344px;
  --reading-width: 768px;
  --header-height: 76px;
  --toc-top: 88px;
  --shadow-button: 0 8px 22px color-mix(in srgb, var(--color-accent-dark) 20%, transparent);
  --shadow-card: 0 24px 64px var(--color-shadow), 0 3px 10px color-mix(in srgb, var(--color-text) 5%, transparent);
  --shadow-soft: 0 14px 36px color-mix(in srgb, var(--color-text) 7%, transparent);
  --transition-fast: 160ms ease;
  --transition-reveal: 580ms cubic-bezier(.2, .75, .25, 1);
}

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

html {
  min-width: 0;
  scroll-behavior: smooth;
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-body);
  text-size-adjust: 100%;
}

html.nav-open {
  overflow: hidden;
}

body {
  min-width: 0;
  min-height: 100vh;
  margin: 0;
  overflow-x: clip;
  background:
    radial-gradient(circle at 50% 18%, var(--color-accent-soft), transparent 28rem),
    var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-body);
  line-height: 1.7;
}

img,
svg,
video,
canvas {
  display: block;
  max-width: 100%;
}

img {
  height: auto;
}

button,
input,
select,
textarea {
  color: inherit;
  font: inherit;
}

button,
summary,
select {
  cursor: pointer;
}

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

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

ul,
ol {
  padding-left: 1.35em;
}

code,
kbd,
samp,
pre {
  font-family: var(--font-mono);
}

code {
  overflow-wrap: anywhere;
}

pre {
  max-width: 100%;
  overflow-x: auto;
  padding: 20px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-text);
  color: var(--color-panel);
  -webkit-overflow-scrolling: touch;
}

table {
  border-collapse: collapse;
}

th,
td {
  text-align: left;
}

:focus-visible {
  outline: 3px solid var(--color-accent-soft);
  outline-offset: 3px;
}

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

.wrap {
  width: min(100%, calc(var(--page-width) + (var(--gutter) * 2)));
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.reading-wrap {
  width: min(100%, calc(var(--reading-width) + (var(--gutter) * 2)));
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.section {
  position: relative;
  overflow-x: clip;
  padding-top: clamp(64px, 9vw, 112px);
  padding-bottom: clamp(64px, 9vw, 112px);
}

.section-compact {
  padding-top: clamp(42px, 6vw, 72px);
  padding-bottom: clamp(42px, 6vw, 72px);
}

.section-heading {
  max-width: 800px;
  margin-bottom: 38px;
}

.section-heading.is-centered {
  margin-inline: auto;
  text-align: center;
}

.kicker,
.badge,
.tag {
  display: inline-flex;
  max-width: 100%;
  min-height: 29px;
  align-items: center;
  gap: 8px;
  overflow: hidden;
  padding: 4px 12px;
  border: 1px solid color-mix(in srgb, var(--color-accent) 34%, var(--color-border));
  border-radius: var(--radius-pill);
  background: var(--color-panel);
  color: var(--color-accent-dark);
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: .04em;
  line-height: 1.4;
}

.status-dot,
.kicker-dot {
  width: 7px;
  height: 7px;
  flex: 0 0 auto;
  border-radius: var(--radius-pill);
  background: var(--color-success);
  box-shadow: 0 0 0 4px color-mix(in srgb, var(--color-success) 12%, transparent);
}

h1,
h2,
h3,
h4 {
  margin-top: 0;
  color: var(--color-text);
  font-family: var(--font-display);
  text-wrap: balance;
}

h1,
.hero-title {
  max-width: 980px;
  font-size: clamp(52px, 5vw, 72px);
  font-weight: 850;
  line-height: 1.1;
  letter-spacing: -.02em;
}

h2 {
  font-size: clamp(32px, 3.6vw, 50px);
  font-weight: 820;
  line-height: 1.15;
  letter-spacing: -.018em;
}

h3 {
  font-size: clamp(21px, 2vw, 28px);
  font-weight: 780;
  line-height: 1.25;
}

h4 {
  font-size: 18px;
  line-height: 1.35;
}

.title-accent {
  position: relative;
  display: inline-block;
  color: var(--color-accent-dark);
  white-space: nowrap;
}

.title-accent::after {
  position: absolute;
  right: 3px;
  bottom: -2px;
  left: 3px;
  z-index: -1;
  height: 8px;
  border-radius: var(--radius-pill);
  background: color-mix(in srgb, var(--color-accent) 25%, transparent);
  content: "";
}

.no-break {
  white-space: nowrap;
}

.lead {
  max-width: 760px;
  color: var(--color-muted);
  font-size: clamp(17px, 1.7vw, 21px);
  line-height: 1.75;
}

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

.mono {
  font-family: var(--font-mono);
}

.button,
.primary-cta,
.secondary-cta {
  display: inline-flex;
  min-height: 48px;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 0 22px;
  border: 1px solid transparent;
  border-radius: var(--radius-pill);
  font-size: 14px;
  font-weight: 750;
  line-height: 1;
  transition: transform var(--transition-fast), box-shadow var(--transition-fast), background var(--transition-fast), border-color var(--transition-fast);
}

.button svg,
.primary-cta svg,
.secondary-cta svg {
  width: 17px;
  height: 17px;
  flex: 0 0 auto;
  stroke: currentColor;
}

.button.button-primary,
.primary-cta {
  border-color: var(--color-accent);
  background: var(--color-accent);
  color: var(--color-white);
  box-shadow: var(--shadow-button);
}

.button.button-secondary,
.secondary-cta {
  border-color: var(--color-border);
  background: var(--color-white);
  color: var(--color-text);
}

.button-dark {
  border-color: var(--color-text);
  background: var(--color-text);
  color: var(--color-white);
}

.button-ghost {
  border-color: transparent;
  background: transparent;
  color: var(--color-accent-dark);
}

.button:hover,
.primary-cta:hover,
.secondary-cta:hover {
  transform: translateY(-2px);
}

.button:active,
.primary-cta:active,
.secondary-cta:active {
  transform: translateY(0);
}

.button[disabled] {
  cursor: not-allowed;
  opacity: .48;
  transform: none;
}

.panel,
.card {
  min-width: 0;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  background: var(--color-panel);
  box-shadow: var(--shadow-soft);
}

.card {
  padding: clamp(22px, 3vw, 34px);
}

.tilt {
  transform: rotate(-.45deg);
}

.reveal {
  transition: opacity var(--transition-reveal), transform var(--transition-reveal);
}

.reveal.pending {
  opacity: 0;
  transform: translateY(16px);
}

.reveal.shown {
  opacity: 1;
  transform: none;
}

.site-header {
  position: relative;
  z-index: 100;
  height: var(--header-height);
  border-bottom: 1px solid color-mix(in srgb, var(--color-border) 78%, transparent);
  background: color-mix(in srgb, var(--color-bg) 90%, transparent);
  backdrop-filter: blur(16px);
}

.site-header.is-sticky {
  position: sticky;
  top: 0;
}

.header-inner {
  width: min(100%, calc(var(--page-width) + (var(--gutter) * 2)));
  height: 100%;
  margin-inline: auto;
  padding-inline: var(--gutter);
  display: flex;
  align-items: center;
  gap: 20px;
}

.brand {
  display: inline-flex;
  flex: 0 0 auto;
  align-items: center;
  gap: 11px;
  white-space: nowrap;
}

.brand-logo {
  width: 38px;
  height: 38px;
  flex: 0 0 auto;
  border-radius: var(--radius-sm);
  box-shadow: 0 7px 17px color-mix(in srgb, var(--color-accent-dark) 22%, transparent);
}

.brand-copy {
  display: inline-flex;
  align-items: baseline;
  gap: 7px;
}

.brand-main {
  font-size: 18px;
  font-weight: 820;
  letter-spacing: -.02em;
}

.brand-local {
  color: var(--color-muted);
  font-size: 12px;
  font-weight: 560;
}

.main-nav {
  min-width: 0;
  margin-left: auto;
  display: flex;
  align-items: center;
  white-space: nowrap;
}

.nav-link {
  position: relative;
  padding: 10px 9px;
  color: var(--color-muted);
  font-size: 13px;
  font-weight: 650;
  transition: color var(--transition-fast);
}

.nav-link + .nav-link::before {
  position: absolute;
  left: -2px;
  color: color-mix(in srgb, var(--color-muted) 48%, transparent);
  content: "·";
}

.nav-link:hover,
.nav-link[aria-current="page"] {
  color: var(--color-text);
}

.nav-link[aria-current="page"]::after {
  position: absolute;
  right: 9px;
  bottom: 3px;
  left: 9px;
  height: 2px;
  border-radius: var(--radius-pill);
  background: var(--color-accent);
  content: "";
}

.header-tools {
  position: relative;
  display: flex;
  flex: 0 0 auto;
  align-items: center;
  gap: 8px;
}

.language-switch {
  position: relative;
}

.language-trigger {
  display: inline-flex;
  min-height: 40px;
  align-items: center;
  gap: 7px;
  padding: 0 12px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-pill);
  background: var(--color-white);
  color: var(--color-muted);
  font-size: 12px;
  font-weight: 650;
}

.language-trigger svg {
  width: 15px;
  height: 15px;
  stroke: currentColor;
}

.language-menu {
  position: absolute;
  top: calc(100% + 10px);
  right: 0;
  z-index: 105;
  width: 170px;
  padding: 7px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-white);
  box-shadow: var(--shadow-card);
}

.language-menu[hidden] {
  display: none;
}

.language-menu a {
  display: flex;
  min-height: 40px;
  align-items: center;
  padding: 0 11px;
  border-radius: var(--radius-sm);
  color: var(--color-muted);
  font-size: 13px;
}

.language-menu a:hover,
.language-menu a[aria-current="true"] {
  background: var(--color-panel-strong);
  color: var(--color-text);
}

.login-button {
  display: inline-flex;
  min-height: 40px;
  align-items: center;
  justify-content: center;
  padding: 0 18px;
  border: 1px solid var(--color-text);
  border-radius: var(--radius-pill);
  background: var(--color-text);
  color: var(--color-white);
  font-size: 13px;
  font-weight: 750;
  transition: background var(--transition-fast), transform var(--transition-fast);
}

.login-button:hover {
  transform: translateY(-1px);
  background: var(--color-accent-dark);
}

.menu-toggle {
  display: none;
  width: 44px;
  min-width: 44px;
  height: 44px;
  min-height: 44px;
  padding: 0;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-pill);
  background: var(--color-white);
}

.menu-toggle svg {
  width: 20px;
  height: 20px;
  stroke: currentColor;
}

.mobile-nav {
  display: none;
}

.mobile-nav[hidden] {
  display: none;
}

.mobile-nav a {
  display: flex;
  width: 100%;
  min-height: 48px;
  align-items: center;
  padding: 0 16px;
  border-bottom: 1px solid var(--color-border);
  font-size: 15px;
  font-weight: 680;
}

.mobile-nav a[aria-current="page"] {
  color: var(--color-accent-dark);
}

.mobile-language-label {
  padding: 18px 16px 6px;
  color: var(--color-muted);
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
}

.nav-veil {
  display: none;
}

.site-footer {
  position: relative;
  overflow-x: clip;
  border-top: 1px solid var(--color-border);
  background: var(--color-panel);
}

.footer-main {
  padding-top: 64px;
  padding-bottom: 48px;
  display: grid;
  grid-template-columns: minmax(220px, 1.3fr) repeat(3, minmax(150px, 1fr));
  gap: 42px;
}

.footer-brand p {
  max-width: 360px;
  margin-top: 18px;
  color: var(--color-muted);
  font-size: 14px;
}

.footer-column {
  min-width: 0;
}

.footer-column h2 {
  margin-bottom: 16px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .07em;
}

.footer-links {
  display: grid;
  gap: 8px;
}

.footer-links a {
  width: fit-content;
  max-width: 100%;
  color: var(--color-muted);
  font-size: 13px;
  overflow-wrap: anywhere;
}

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

.footer-bottom {
  padding-top: 22px;
  padding-bottom: 26px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  border-top: 1px solid var(--color-border);
  color: var(--color-muted);
  font-size: 12px;
}

.footer-legal,
.footer-languages {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 16px;
}

.prose {
  min-width: 0;
  color: var(--color-text);
}

.prose h2,
.prose h3 {
  scroll-margin-top: calc(var(--toc-top) + 72px);
}

.prose p,
.prose li {
  overflow-wrap: anywhere;
}

.prose a {
  color: var(--color-accent-dark);
  text-decoration: underline;
  text-decoration-color: var(--color-accent-soft);
  text-underline-offset: 3px;
}

.prose blockquote {
  margin-inline: 0;
}

.prose img {
  border-radius: var(--radius-md);
}

body:has(.toc-tabs) section[id] {
  scroll-margin-top: calc(var(--toc-top) + 76px);
}

@media (max-width: 1180px) {
  .main-nav {
    display: none;
  }

  .header-tools {
    margin-left: auto;
  }

  .menu-toggle {
    display: inline-flex;
  }

  .mobile-nav {
    position: absolute;
    top: var(--header-height);
    right: 0;
    left: 0;
    z-index: 104;
    max-height: calc(100dvh - var(--header-height));
    overflow-y: auto;
    overscroll-behavior: contain;
    border-top: 1px solid var(--color-border);
    border-bottom: 1px solid var(--color-border);
    background: var(--color-bg);
    box-shadow: var(--shadow-card);
    -webkit-overflow-scrolling: touch;
  }

  .mobile-nav.is-open {
    display: block;
  }

  .nav-veil.is-open {
    position: fixed;
    inset: var(--header-height) 0 0;
    z-index: 90;
    display: block;
    border: 0;
    background: color-mix(in srgb, var(--color-text) 24%, transparent);
  }
}

@media (max-width: 768px) {
  :root {
    --header-height: 68px;
    --toc-top: 76px;
  }

  h1,
  .hero-title {
    font-size: clamp(28px, 9.6vw, 40px);
    line-height: 1.12;
    letter-spacing: -.015em;
  }

  h2 {
    font-size: clamp(27px, 7.4vw, 38px);
  }

  .brand-logo {
    width: 34px;
    height: 34px;
  }

  .brand-main {
    font-size: 16px;
  }

  .brand-local,
  .language-trigger span {
    display: none;
  }

  .language-trigger {
    width: 40px;
    padding: 0;
    justify-content: center;
  }

  .login-button {
    min-height: 40px;
    padding-inline: 14px;
  }

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

  .footer-brand {
    grid-column: 1 / -1;
  }

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

  .tilt {
    transform: none;
  }
}

@media (max-width: 640px) {
  :root {
    --gutter: 16px;
  }

  .title-accent,
  .no-break {
    white-space: normal;
  }

  body,
  main,
  section,
  article,
  header,
  footer {
    max-width: 100%;
  }

  .header-inner {
    gap: 8px;
  }

  .brand-copy {
    gap: 0;
  }

  .header-tools {
    margin-left: auto;
    gap: 5px;
  }

  .button,
  .primary-cta,
  .secondary-cta {
    min-width: 0;
    padding-inline: 18px;
  }

  .section {
    padding-top: 56px;
    padding-bottom: 56px;
  }

  .footer-main {
    grid-template-columns: minmax(0, 1fr);
    gap: 32px;
  }

  .footer-brand {
    grid-column: auto;
  }

  .tilt,
  [class*="tilt"] {
    transform: none;
  }
}

@media (max-width: 380px) {
  .brand-local {
    display: none;
  }

  .login-button {
    padding-inline: 12px;
  }
}

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

  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    animation-duration: .01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .01ms !important;
  }

  .reveal,
  .reveal.pending {
    opacity: 1;
    transform: none;
  }
}