:root {
  --color-bg: #FFFFFF;
  --color-panel: #F7F7F7;
  --color-panel-strong: #EFEFEF;
  --color-border: #E4E4E4;
  --color-accent: #00B140;
  --color-accent-dark: #008A32;
  --color-text: #111312;
  --color-muted: #5D605E;
  --color-success: #0E9F4E;
  --color-warn: #E39A00;
  --color-error: #D8362A;
  --color-on-accent: #FFFFFF;
  --color-on-accent-muted: rgba(255, 255, 255, .94);
  --color-on-accent-faint: rgba(255, 255, 255, .42);
  --color-on-accent-line: rgba(255, 255, 255, .55);
  --color-on-accent-hover: rgba(255, 255, 255, .08);
  --color-accent-soft: rgba(0, 177, 64, .08);
  --color-accent-line: rgba(0, 177, 64, .28);
  --color-overlay: rgba(17, 19, 18, .38);
  --color-flag-red: #CE3A34;
  --color-flag-blue: #27408F;
  --font-display: 'Inter', 'Noto Sans SC', 'Noto Sans JP', 'Noto Sans KR', -apple-system, 'PingFang SC', 'Hiragino Sans', 'Malgun Gothic', sans-serif;
  --font-body: 'Inter', 'Noto Sans SC', 'Noto Sans JP', 'Noto Sans KR', -apple-system, 'PingFang SC', 'Hiragino Sans', 'Malgun Gothic', sans-serif;
  --font-mono: 'JetBrains Mono', 'SFMono-Regular', Consolas, 'Liberation Mono', monospace;
  --radius-xs: 5px;
  --radius-sm: 10px;
  --radius-md: 16px;
  --radius-lg: 22px;
  --radius-panel: 30px;
  --radius-pill: 999px;
  --page-max: 1240px;
  --prose-max: 820px;
  --gutter: clamp(16px, 3vw, 32px);
  --header-height: 62px;
  --section-space: clamp(72px, 9vw, 132px);
  --toc-top: 12px;
  --toc-offset: 86px;
  --line-body: 1.75;
  --transition-fast: 150ms ease;
  --transition-base: 320ms ease;
}

*,
*::before,
*::after {
  box-sizing: border-box;
  min-width: 0;
}

html {
  color-scheme: light;
  scroll-behavior: smooth;
  background: var(--color-bg);
}

html.nav-open {
  overflow: hidden;
}

body {
  margin: 0;
  min-width: 320px;
  overflow-x: clip;
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: var(--line-body);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

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

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

img {
  height: auto;
}

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

button,
summary {
  cursor: pointer;
}

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

p,
h1,
h2,
h3,
h4,
ul,
ol,
figure,
blockquote {
  margin-top: 0;
}

ul,
ol {
  padding-left: 1.25em;
}

code,
kbd,
samp {
  font-family: var(--font-mono);
  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-panel);
  -webkit-overflow-scrolling: touch;
}

pre code {
  overflow-wrap: normal;
  white-space: pre;
}

table {
  border-collapse: collapse;
}

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

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

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

.prose {
  width: 100%;
  max-width: calc(var(--prose-max) + var(--gutter) * 2);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.section {
  padding-top: var(--section-space);
  padding-bottom: var(--section-space);
  overflow-x: clip;
}

.section-tight {
  padding-top: calc(var(--section-space) * .62);
  padding-bottom: calc(var(--section-space) * .62);
  overflow-x: clip;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  margin-bottom: 18px;
  color: var(--color-accent-dark);
  font-size: 13px;
  font-weight: 750;
  letter-spacing: .08em;
}

.eyebrow::before {
  width: 8px;
  height: 8px;
  flex: 0 0 auto;
  border-radius: 50%;
  background: var(--color-accent);
  content: "";
}

h1,
h2,
h3,
h4 {
  color: var(--color-text);
  font-family: var(--font-display);
  line-height: 1.16;
  text-wrap: balance;
}

h1 {
  margin-bottom: 24px;
  font-size: clamp(52px, 6vw, 72px);
  font-weight: 900;
  letter-spacing: -.018em;
}

h2 {
  margin-bottom: 22px;
  font-size: clamp(34px, 4vw, 52px);
  font-weight: 850;
  letter-spacing: -.015em;
}

h3 {
  margin-bottom: 14px;
  font-size: clamp(22px, 2.5vw, 30px);
  font-weight: 800;
}

h4 {
  margin-bottom: 10px;
  font-size: 19px;
  font-weight: 750;
}

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

.lead {
  max-width: 760px;
  font-size: clamp(18px, 2vw, 22px);
  line-height: 1.7;
}

.text-accent {
  color: var(--color-accent-dark);
}

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

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

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

.panel,
.card {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  background: var(--color-bg);
}

.panel {
  padding: clamp(24px, 4vw, 48px);
}

.card {
  padding: 26px;
}

.panel-muted,
.card-muted {
  background: var(--color-panel);
}

.badge,
.tag,
.chip {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  max-width: 100%;
  min-height: 28px;
  padding: 5px 11px;
  overflow: hidden;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-pill);
  color: var(--color-muted);
  font-size: 12px;
  font-weight: 700;
  line-height: 1.3;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.badge-accent {
  border-color: var(--color-accent-line);
  background: var(--color-accent-soft);
  color: var(--color-accent-dark);
}

.status-dot {
  width: 8px;
  height: 8px;
  flex: 0 0 auto;
  border-radius: 50%;
  background: var(--color-success);
}

.btn {
  display: inline-flex;
  min-height: 48px;
  align-items: center;
  justify-content: center;
  gap: 9px;
  padding: 11px 24px;
  border: 1.5px solid transparent;
  border-radius: var(--radius-pill);
  cursor: pointer;
  font-weight: 750;
  line-height: 1.2;
  text-align: center;
  transition: color var(--transition-fast), background-color var(--transition-fast), border-color var(--transition-fast), transform var(--transition-fast);
}

.btn:hover {
  transform: translateY(-2px);
}

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

.btn-primary:hover {
  border-color: var(--color-accent-dark);
  background: var(--color-accent-dark);
}

.btn-secondary {
  border-color: var(--color-text);
  background: var(--color-bg);
  color: var(--color-text);
}

.btn-secondary:hover {
  background: var(--color-panel-strong);
}

.btn-quiet {
  border-color: var(--color-border);
  background: transparent;
  color: var(--color-text);
}

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

.button-row {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

.site-header {
  position: relative;
  z-index: 100;
  height: var(--header-height);
  background: var(--color-bg);
}

.topbar {
  height: var(--header-height);
  display: flex;
  align-items: center;
  gap: 24px;
  padding-inline: 26px;
}

.brand {
  display: inline-flex;
  flex: 0 0 auto;
  align-items: center;
  gap: 10px;
}

.brand-logo {
  width: 32px;
  height: 32px;
  flex: 0 0 auto;
}

.brand-name {
  font-family: var(--font-display);
  font-size: 19px;
  font-weight: 850;
  letter-spacing: .02em;
}

.brand-local {
  color: var(--color-muted);
  font-size: 14px;
  font-weight: 550;
}

.mainnav {
  display: flex;
  align-items: center;
  gap: 3px;
  margin-inline: auto;
}

.mainnav a {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 10px;
  border-radius: var(--radius-pill);
  color: var(--color-muted);
  font-size: 13px;
  font-weight: 550;
  white-space: nowrap;
  transition: color var(--transition-fast), background-color var(--transition-fast);
}

.mainnav a:hover,
.mainnav a.is-active {
  background: var(--color-panel);
  color: var(--color-text);
}

.mainnav a.is-active {
  font-weight: 750;
}

.nav-icon {
  width: 16px;
  height: 16px;
  flex: 0 0 auto;
  fill: none;
  stroke: currentColor;
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke-width: 1.7;
}

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

.lang-control {
  position: relative;
}

.lang-button,
.menu-toggle {
  min-width: 44px;
  min-height: 44px;
  border: 0;
  border-radius: var(--radius-pill);
  background: transparent;
  color: var(--color-muted);
}

.lang-button {
  padding-inline: 12px;
  font-size: 13px;
}

.lang-button:hover,
.menu-toggle:hover {
  background: var(--color-panel);
  color: var(--color-text);
}

.lang-menu {
  position: absolute;
  top: calc(100% + 7px);
  right: 0;
  width: 154px;
  padding: 7px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-bg);
}

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

.lang-menu a {
  display: block;
  min-height: 42px;
  padding: 9px 11px;
  border-radius: var(--radius-sm);
  color: var(--color-muted);
  font-size: 13px;
}

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

.login-button {
  display: inline-flex;
  min-height: 40px;
  align-items: center;
  padding: 7px 18px;
  border: 1.5px solid var(--color-text);
  border-radius: var(--radius-pill);
  color: var(--color-text);
  font-size: 13px;
  font-weight: 700;
  white-space: nowrap;
}

.login-button:hover {
  background: var(--color-panel-strong);
}

.menu-toggle {
  display: none;
  align-items: center;
  justify-content: center;
  padding: 0;
}

.menu-toggle svg {
  width: 22px;
  height: 22px;
  fill: none;
  stroke: currentColor;
  stroke-linecap: round;
  stroke-width: 2;
}

.mobile-veil {
  position: fixed;
  z-index: 89;
  inset: var(--header-height) 0 0;
  border: 0;
  background: var(--color-overlay);
}

.mobile-veil[hidden],
.mobile-drawer[hidden] {
  display: none;
}

.mobile-drawer {
  position: fixed;
  z-index: 101;
  top: var(--header-height);
  right: 0;
  width: min(390px, 100%);
  max-height: calc(100dvh - var(--header-height));
  padding: 12px 16px 22px;
  overflow-y: auto;
  overscroll-behavior: contain;
  border-top: 1px solid var(--color-border);
  border-left: 1px solid var(--color-border);
  background: var(--color-bg);
}

.mobile-drawer ul {
  margin: 0;
  padding: 0;
  list-style: none;
}

.mobile-drawer a {
  display: flex;
  width: 100%;
  min-height: 48px;
  align-items: center;
  gap: 11px;
  padding: 11px 12px;
  border-radius: var(--radius-sm);
  color: var(--color-muted);
}

.mobile-drawer a:hover,
.mobile-drawer a.is-active {
  background: var(--color-panel);
  color: var(--color-text);
}

.mobile-languages {
  margin-top: 12px;
  padding-top: 12px;
  border-top: 1px solid var(--color-border);
}

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

.footer-grid {
  display: grid;
  grid-template-columns: 1.35fr 1fr 1fr 1fr;
  gap: 40px;
  padding-top: 68px;
  padding-bottom: 52px;
}

.footer-brand p {
  max-width: 370px;
  margin-top: 18px;
}

.footer-heading {
  margin-bottom: 14px;
  font-size: 14px;
  font-weight: 800;
}

.footer-links {
  margin: 0;
  padding: 0;
  list-style: none;
}

.footer-links a {
  display: inline-block;
  padding-block: 5px;
  color: var(--color-muted);
  font-size: 14px;
}

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

.footer-bottom {
  display: flex;
  justify-content: space-between;
  gap: 24px;
  padding-top: 20px;
  padding-bottom: 28px;
  border-top: 1px solid var(--color-border);
  color: var(--color-muted);
  font-size: 13px;
}

.reveal {
  transition: opacity 560ms ease, transform 560ms ease;
}

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

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

.tilt,
.tilt-card {
  transform: rotate(-.35deg);
}

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

@media (max-width: 1120px) {
  .mainnav a span {
    display: none;
  }

  .mainnav a {
    padding-inline: 9px;
  }

  .footer-grid {
    grid-template-columns: 1.4fr 1fr 1fr;
  }
}

@media (max-width: 820px) {
  .topbar {
    gap: 12px;
    padding-inline: var(--gutter);
  }

  .mainnav,
  .lang-control {
    display: none;
  }

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

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

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

@media (max-width: 768px) {
  h1 {
    font-size: clamp(32px, 9.8vw, 40px);
    line-height: 1.12;
    letter-spacing: -.012em;
  }

  h2 {
    font-size: clamp(28px, 8vw, 38px);
  }

  .section {
    padding-top: 72px;
    padding-bottom: 72px;
  }

  .button-row .btn {
    flex: 1 1 180px;
  }
}

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

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

  body {
    font-size: 15px;
  }

  .brand-local {
    display: none;
  }

  .login-button {
    min-height: 38px;
    padding-inline: 13px;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 28px;
  }

  .footer-bottom {
    flex-direction: column;
  }

  .panel,
  .card {
    padding: 20px;
  }

  .tilt,
  .tilt-card {
    transform: none;
  }
}

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

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

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