:root {
  --color-canvas: #F4F0E7;
  --color-panel: #E9E4D9;
  --color-panel-deep: #24211F;
  --color-border: #B8C0C4;
  --color-border-soft: #D7D1C5;
  --color-accent: #C46A2B;
  --color-accent-dark: #8C431A;
  --color-text: #1D1B19;
  --color-muted: #6D6861;
  --color-success: #71877A;
  --color-warn: #A65D25;
  --color-error: #A14336;
  --color-green-panel: #D6DDD3;
  --color-blue-panel: #D7DEE2;
  --color-sun: #E7C794;
  --color-white: #FFFDF8;
  --color-paper: #EEE9DF;
  --color-line-faint: rgba(29, 27, 25, 0.08);
  --color-dark-faint: rgba(29, 27, 25, 0.16);
  --color-dark-medium: rgba(29, 27, 25, 0.52);
  --color-light-faint: rgba(255, 253, 248, 0.68);
  --color-light-line: rgba(255, 253, 248, 0.18);
  --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", "SFMono-Regular", Consolas, monospace;
  --radius-xs: 4px;
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 22px;
  --radius-pill: 999px;
  --header-height: 74px;
  --gutter: clamp(18px, 3.35vw, 52px);
  --page-width: 1440px;
  --content-width: 1160px;
  --reading-width: 768px;
  --section-space: clamp(72px, 9vw, 132px);
  --toc-offset: 86px;
  --transition-fast: 180ms ease;
  --transition-calm: 320ms ease;
  --shadow-float: 0 8px 22px rgba(29, 27, 25, 0.12);
  --shadow-paper: 8px 8px 0 rgba(29, 27, 25, 0.08);
}

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

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

html.nav-open {
  overflow: hidden;
}

body {
  min-width: 0;
  margin: 0;
  overflow-x: clip;
  background:
    linear-gradient(var(--color-line-faint) 1px, transparent 1px),
    linear-gradient(90deg, var(--color-line-faint) 1px, transparent 1px),
    var(--color-canvas);
  background-position: -1px -1px;
  background-size: 44px 44px;
  color: var(--color-text);
  font-size: 16px;
  line-height: 1.72;
}

main,
section,
article,
aside,
header,
footer,
nav,
div {
  min-width: 0;
}

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

img {
  height: auto;
}

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

a,
button,
input,
select,
textarea,
summary {
  -webkit-tap-highlight-color: transparent;
}

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

button {
  color: inherit;
}

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

code {
  overflow-wrap: anywhere;
}

pre {
  max-width: 100%;
  margin: 24px 0;
  padding: 20px;
  overflow-x: auto;
  border: 1px solid var(--color-light-line);
  border-radius: var(--radius-sm);
  background: var(--color-panel-deep);
  color: var(--color-white);
  line-height: 1.65;
  white-space: pre;
  -webkit-overflow-scrolling: touch;
}

pre code {
  overflow-wrap: normal;
}

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

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

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

.content-wrap {
  width: min(100%, calc(var(--content-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 {
  padding-top: var(--section-space);
  padding-bottom: var(--section-space);
  overflow-x: clip;
}

.section-tight {
  padding-top: clamp(48px, 6vw, 84px);
  padding-bottom: clamp(48px, 6vw, 84px);
  overflow-x: clip;
}

.section-dark {
  background: var(--color-panel-deep);
  color: var(--color-white);
}

.section-paper {
  background: var(--color-white);
}

.section-heading {
  max-width: 820px;
  margin: 0 0 42px;
}

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

.kicker {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  margin-bottom: 14px;
  color: var(--color-accent-dark);
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.kicker::before {
  width: 28px;
  border-top: 2px solid var(--color-accent);
  content: "";
  flex-shrink: 0;
}

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

h1 {
  margin-bottom: 24px;
  font-size: clamp(52px, 5vw, 68px);
  font-weight: 820;
  letter-spacing: -0.02em;
  line-height: 1.1;
}

h2 {
  margin-bottom: 18px;
  font-size: clamp(34px, 4vw, 50px);
  font-weight: 780;
  letter-spacing: -0.02em;
  line-height: 1.12;
}

h3 {
  margin-bottom: 12px;
  font-size: clamp(23px, 2.4vw, 30px);
  font-weight: 740;
  line-height: 1.25;
}

h4 {
  margin-bottom: 10px;
  font-size: 19px;
  font-weight: 720;
  line-height: 1.35;
}

p {
  margin-top: 0;
  margin-bottom: 1.15em;
}

.lead {
  max-width: 760px;
  color: var(--color-muted);
  font-size: clamp(18px, 2vw, 22px);
  line-height: 1.65;
}

.section-dark .lead,
.section-dark .muted {
  color: var(--color-light-faint);
}

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

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

.no-break {
  display: inline-block;
  white-space: nowrap;
}

.text-link {
  color: var(--color-accent-dark);
  font-weight: 700;
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 4px;
}

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

.button,
.cta {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 18px;
  min-height: 52px;
  padding: 0 20px;
  border: 1px solid var(--color-text);
  border-radius: var(--radius-sm);
  background: transparent;
  color: var(--color-text);
  cursor: pointer;
  font-size: 15px;
  font-weight: 720;
  line-height: 1.2;
  text-align: center;
  transition:
    transform var(--transition-fast),
    border-color var(--transition-fast),
    background-color var(--transition-fast),
    color var(--transition-fast);
}

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

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

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

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

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

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

.button-quiet:hover,
.cta-secondary:hover {
  background: var(--color-panel);
}

.button[disabled],
.button.is-disabled {
  border-color: var(--color-border);
  background: var(--color-panel);
  color: var(--color-muted);
  cursor: not-allowed;
  transform: none;
}

.button-arrow {
  flex-shrink: 0;
  font-family: var(--font-mono);
  font-size: 18px;
}

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

.badge,
.chip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  max-width: 100%;
  min-height: 30px;
  padding: 4px 11px;
  overflow: hidden;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-pill);
  background: var(--color-panel);
  color: var(--color-text);
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 650;
  line-height: 1.3;
  white-space: nowrap;
}

.badge-dot {
  width: 8px;
  height: 8px;
  border-radius: var(--radius-pill);
  background: var(--color-success);
  flex-shrink: 0;
}

.badge-accent {
  border-color: var(--color-accent);
  background: var(--color-accent);
  color: var(--color-white);
}

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

.panel {
  padding: clamp(22px, 3vw, 36px);
}

.card {
  padding: 24px;
  transition:
    transform var(--transition-calm),
    border-color var(--transition-calm);
}

.card:hover {
  border-color: var(--color-text);
  transform: translateY(-3px);
}

.site-header {
  position: relative;
  z-index: 60;
  min-height: var(--header-height);
  border-bottom: 1px solid var(--color-border-soft);
  background: var(--color-white);
}

.header-inner {
  position: relative;
  display: flex;
  align-items: stretch;
  width: min(100%, var(--page-width));
  min-height: var(--header-height);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.brand {
  display: flex;
  align-items: center;
  gap: 11px;
  min-width: 196px;
  margin-right: 14px;
  flex: 0 0 auto;
}

.brand-logo {
  width: 34px;
  height: 34px;
  object-fit: contain;
  flex-shrink: 0;
}

.brand-wording {
  display: flex;
  align-items: baseline;
  gap: 7px;
  white-space: nowrap;
}

.brand-latin {
  font-family: var(--font-display);
  font-size: 19px;
  font-weight: 800;
  letter-spacing: -0.02em;
}

.brand-local {
  color: var(--color-muted);
  font-size: 13px;
  font-weight: 540;
  letter-spacing: 0.04em;
}

.primary-nav {
  display: flex;
  align-items: stretch;
  min-width: 0;
}

.nav-link {
  position: relative;
  display: flex;
  align-items: center;
  min-height: var(--header-height);
  padding: 2px 10px 0;
  color: var(--color-muted);
  font-size: 13px;
  font-weight: 620;
  white-space: nowrap;
  transition:
    color var(--transition-fast),
    background-color var(--transition-fast);
}

.nav-link::after {
  position: absolute;
  right: 10px;
  bottom: 0;
  left: 10px;
  height: 3px;
  background: var(--color-accent);
  content: "";
  opacity: 0;
  transform: scaleX(0.35);
  transform-origin: center;
  transition:
    opacity var(--transition-fast),
    transform var(--transition-fast);
}

.nav-link:hover {
  background: var(--color-paper);
  color: var(--color-text);
}

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

.nav-link[aria-current="page"]::after {
  opacity: 1;
  transform: scaleX(1);
}

.header-tools {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 8px;
  margin-left: auto;
  flex: 0 0 auto;
}

.language-control {
  position: relative;
}

.language-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 42px;
  padding: 0 10px;
  border: 0;
  background: transparent;
  color: var(--color-muted);
  cursor: pointer;
  font-size: 12px;
  font-weight: 620;
  white-space: nowrap;
}

.language-button:hover {
  color: var(--color-text);
}

.language-menu {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  z-index: 72;
  width: 168px;
  padding: 7px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-white);
  box-shadow: var(--shadow-float);
}

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

.language-menu a {
  display: flex;
  align-items: center;
  min-height: 42px;
  padding: 8px 10px;
  border-radius: var(--radius-xs);
  font-size: 13px;
}

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

.login-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 42px;
  padding: 0 20px;
  border: 1px solid var(--color-panel-deep);
  border-radius: var(--radius-xs);
  background: var(--color-panel-deep);
  color: var(--color-white);
  font-size: 13px;
  font-weight: 720;
  white-space: nowrap;
  transition:
    border-color var(--transition-fast),
    background-color var(--transition-fast);
}

.login-button:hover {
  border-color: var(--color-accent-dark);
  background: var(--color-accent-dark);
}

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

.menu-toggle-lines,
.menu-toggle-lines::before,
.menu-toggle-lines::after {
  display: block;
  width: 19px;
  height: 2px;
  background: var(--color-text);
  content: "";
  transition: transform var(--transition-fast);
}

.menu-toggle-lines {
  position: relative;
}

.menu-toggle-lines::before {
  position: absolute;
  top: -6px;
}

.menu-toggle-lines::after {
  position: absolute;
  top: 6px;
}

.menu-toggle[aria-expanded="true"] .menu-toggle-lines {
  background: transparent;
}

.menu-toggle[aria-expanded="true"] .menu-toggle-lines::before {
  top: 0;
  transform: rotate(45deg);
}

.menu-toggle[aria-expanded="true"] .menu-toggle-lines::after {
  top: 0;
  transform: rotate(-45deg);
}

.mobile-nav {
  display: none;
}

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

.mobile-nav a {
  display: flex;
  align-items: center;
  width: 100%;
  min-height: 48px;
  padding: 10px 18px;
  border-bottom: 1px solid var(--color-border-soft);
  font-size: 15px;
  font-weight: 650;
}

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

.mobile-language-title {
  padding: 18px 18px 5px;
  color: var(--color-muted);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
}

.nav-veil {
  display: none;
}

.nav-veil.is-visible {
  display: block;
}

.site-footer {
  overflow-x: clip;
  background: var(--color-panel-deep);
  color: var(--color-white);
}

.footer-main {
  display: grid;
  grid-template-columns: minmax(230px, 1.25fr) repeat(3, minmax(150px, 1fr));
  gap: clamp(32px, 5vw, 76px);
  padding-top: 72px;
  padding-bottom: 54px;
}

.footer-brand {
  max-width: 340px;
}

.footer-brand-line {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 18px;
}

.footer-logo {
  width: 38px;
  height: 38px;
  object-fit: contain;
  flex-shrink: 0;
}

.footer-brand-name {
  font-size: 22px;
  font-weight: 800;
}

.footer-description {
  color: var(--color-light-faint);
  font-size: 14px;
}

.footer-title {
  margin-bottom: 15px;
  color: var(--color-white);
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.08em;
}

.footer-links {
  display: grid;
  gap: 7px;
}

.footer-links a {
  width: fit-content;
  color: var(--color-light-faint);
  font-size: 14px;
}

.footer-links a:hover {
  color: var(--color-white);
  text-decoration: underline;
  text-underline-offset: 4px;
}

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 22px;
  padding-top: 22px;
  padding-bottom: 24px;
  border-top: 1px solid var(--color-light-line);
  color: var(--color-light-faint);
  font-family: var(--font-mono);
  font-size: 11px;
}

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

.reveal {
  transition:
    opacity 620ms ease,
    transform 620ms ease;
}

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

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

.prose {
  font-size: 17px;
}

.prose h2,
.prose h3 {
  scroll-margin-top: var(--toc-offset);
}

.prose h2 {
  margin-top: 2.2em;
}

.prose h3 {
  margin-top: 1.7em;
}

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

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

.prose li {
  margin-bottom: 0.55em;
}

.prose img {
  margin: 30px auto;
}

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

.tilt-soft {
  transform: rotate(-0.45deg);
}

@media (max-width: 1280px) {
  :root {
    --gutter: 28px;
  }

  .brand {
    min-width: 166px;
  }

  .brand-local {
    display: none;
  }

  .nav-link {
    padding-inline: 7px;
    font-size: 12px;
  }

  .nav-link::after {
    right: 7px;
    left: 7px;
  }

  .language-button {
    padding-inline: 6px;
  }
}

@media (max-width: 1060px) {
  .primary-nav,
  .language-control {
    display: none;
  }

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

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

  .mobile-nav {
    position: fixed;
    top: var(--header-height);
    right: 0;
    left: 0;
    z-index: 68;
    max-height: calc(100dvh - var(--header-height));
    overflow-y: auto;
    border-top: 1px solid var(--color-border-soft);
    background: var(--color-white);
    overscroll-behavior: contain;
    -webkit-overflow-scrolling: touch;
  }

  .nav-veil {
    position: fixed;
    inset: var(--header-height) 0 0;
    z-index: 55;
    background: var(--color-dark-medium);
  }

  .site-header {
    z-index: 60;
  }
}

@media (max-width: 768px) {
  :root {
    --gutter: 20px;
    --header-height: 66px;
    --toc-offset: 78px;
  }

  h1 {
    font-size: clamp(32px, 9vw, 40px);
    line-height: 1.12;
  }

  h2 {
    font-size: clamp(29px, 8vw, 38px);
  }

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

  .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;
  }

  .prose {
    font-size: 16px;
  }
}

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

  body {
    background-size: 36px 36px;
  }

  .wrap,
  .content-wrap,
  .reading-wrap {
    padding-inline: var(--gutter);
  }

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

  .brand {
    min-width: 0;
    margin-right: 8px;
  }

  .brand-logo {
    width: 31px;
    height: 31px;
  }

  .brand-latin {
    font-size: 17px;
  }

  .login-button {
    min-height: 44px;
    padding-inline: 13px;
  }

  .button,
  .cta {
    width: 100%;
  }

  .button-row {
    display: grid;
    grid-template-columns: 1fr;
  }

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

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

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

  pre {
    padding: 16px;
    font-size: 13px;
  }
}

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

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

  *,
  *::before,
  *::after {
    animation: none !important;
    transition-duration: 0.01ms !important;
  }

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