:root {
  --color-bg: #F6F0E4;
  --color-panel: #FFF9EE;
  --color-panel-secondary: #E9DFD0;
  --color-border: #CBBEAD;
  --color-accent: #B84C3A;
  --color-accent-dark: #793529;
  --color-text: #332722;
  --color-text-muted: #75665C;
  --color-success: #167A66;
  --color-warning: #C38A25;
  --color-error: #9C302B;
  --color-white: #FFFFFF;
  --color-paper-glow: rgba(255, 249, 238, 0.88);
  --color-paper-soft: rgba(255, 249, 238, 0.64);
  --color-border-soft: rgba(203, 190, 173, 0.52);
  --color-border-faint: rgba(203, 190, 173, 0.25);
  --color-text-faint: rgba(51, 39, 34, 0.16);
  --color-accent-soft: rgba(184, 76, 58, 0.12);
  --color-accent-glow: rgba(184, 76, 58, 0.22);
  --color-success-soft: rgba(22, 122, 102, 0.13);
  --color-success-glow: rgba(22, 122, 102, 0.25);
  --color-warning-soft: rgba(195, 138, 37, 0.15);
  --color-error-soft: rgba(156, 48, 43, 0.12);
  --color-shadow: rgba(71, 48, 36, 0.12);
  --color-shadow-deep: rgba(71, 48, 36, 0.20);
  --color-grain: rgba(121, 53, 41, 0.035);
  --font-display: Georgia, "Times New Roman", "Noto Sans SC", "Noto Sans JP", "Noto Sans KR", 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-none: 0;
  --radius-xs: 3px;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-pill: 999px;
  --shadow-navigation: 0 1px 0 var(--color-border-soft), 0 12px 34px var(--color-shadow);
  --shadow-card: 7px 7px 0 var(--color-panel-secondary), 0 20px 48px var(--color-shadow);
  --shadow-device: 0 30px 70px var(--color-shadow), 0 8px 18px var(--color-shadow);
  --shadow-button: 0 9px 22px var(--color-success-glow);
  --page-width: 1360px;
  --reading-width: 48rem;
  --header-height: 88px;
  --gutter: clamp(16px, 3.2vw, 40px);
  --section-space: clamp(64px, 9vw, 128px);
  --toc-offset: 16px;
  --toc-height: 58px;
  --ease-soft: cubic-bezier(0.22, 1, 0.36, 1);
}

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

html {
  min-width: 0;
  scroll-behavior: smooth;
}

html.nav-open {
  overflow: hidden;
}

body {
  min-width: 0;
  min-height: 100vh;
  margin: 0;
  overflow-x: clip;
  color: var(--color-text);
  background:
    radial-gradient(circle at 16% 12%, var(--color-paper-glow) 0, var(--color-paper-soft) 20%, transparent 45%),
    linear-gradient(112deg, transparent 0 64%, var(--color-accent-soft) 64% 64.1%, transparent 64.1%),
    var(--color-bg);
  font-family: var(--font-body);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

body::before {
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  content: "";
  opacity: 0.72;
  background:
    repeating-linear-gradient(8deg, transparent 0 5px, var(--color-grain) 5px 6px, transparent 6px 12px),
    repeating-linear-gradient(94deg, transparent 0 17px, var(--color-grain) 17px 18px, transparent 18px 29px);
  mix-blend-mode: multiply;
}

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

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

button,
summary {
  cursor: pointer;
}

button {
  border: 0;
}

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

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

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

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

:not(pre) > code {
  padding: 0.12em 0.35em;
  overflow-wrap: anywhere;
  color: var(--color-accent-dark);
  border: 1px solid var(--color-border-soft);
  border-radius: var(--radius-xs);
  background: var(--color-panel-secondary);
  font-size: 0.9em;
}

pre {
  max-width: 100%;
  padding: 20px;
  overflow-x: auto;
  overscroll-behavior-inline: contain;
  color: var(--color-panel);
  border-left: 4px solid var(--color-accent);
  background: var(--color-text);
  font-family: var(--font-mono);
  line-height: 1.65;
}

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

table {
  border-collapse: collapse;
}

th,
td {
  padding: 13px 15px;
  border: 1px solid var(--color-border);
  text-align: left;
  vertical-align: top;
}

th {
  background: var(--color-panel-secondary);
  font-size: 0.85rem;
}

hr {
  margin: 36px 0;
  border: 0;
  border-top: 1px solid var(--color-border);
}

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

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

.reading-wrap {
  width: 100%;
  max-width: 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-compact {
  padding-top: calc(var(--section-space) * 0.62);
  padding-bottom: calc(var(--section-space) * 0.62);
}

.grid > *,
.hero > *,
.header-inner > *,
.footer-grid > * {
  min-width: 0;
}

h1,
h2,
h3,
h4 {
  margin-top: 0;
  color: var(--color-text);
  font-family: var(--font-display);
  line-height: 1.16;
}

h1,
.hero-title {
  max-width: 13em;
  margin-bottom: 0;
  font-size: clamp(52px, 5.4vw, 72px);
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.02em;
}

h2 {
  margin-bottom: 20px;
  font-size: clamp(34px, 4vw, 50px);
  letter-spacing: -0.015em;
}

h3 {
  margin-bottom: 14px;
  font-size: clamp(23px, 2.4vw, 31px);
}

h4 {
  margin-bottom: 10px;
  font-size: 1.1rem;
}

.lead {
  max-width: 44rem;
  color: var(--color-text-muted);
  font-size: clamp(18px, 2vw, 22px);
  line-height: 1.75;
}

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

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

.kicker,
.badge,
.tag {
  max-width: 100%;
  overflow: hidden;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--color-accent-dark);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-pill);
  background: var(--color-panel);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.kicker {
  padding: 8px 12px 8px 9px;
  box-shadow: 3px 3px 0 var(--color-panel-secondary);
}

.badge,
.tag {
  padding: 5px 9px;
}

.kicker-dot,
.status-dot,
.icon-dot {
  width: 9px;
  height: 9px;
  flex: 0 0 auto;
  border-radius: var(--radius-pill);
  background: var(--color-accent);
  box-shadow: 0 0 0 4px var(--color-accent-soft);
}

.status-dot.is-success {
  background: var(--color-success);
  box-shadow: 0 0 0 4px var(--color-success-soft);
}

.status-dot.is-warning {
  background: var(--color-warning);
  box-shadow: 0 0 0 4px var(--color-warning-soft);
}

.button,
.cta {
  min-height: 50px;
  padding: 0 22px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  color: var(--color-text);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xs);
  background: var(--color-panel);
  font-size: 0.88rem;
  font-weight: 750;
  letter-spacing: 0.01em;
  text-decoration: none;
  transition: transform 180ms ease, box-shadow 180ms ease, background-color 180ms ease;
}

.button svg,
.cta svg {
  width: 17px;
  height: 17px;
  flex: 0 0 auto;
}

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

.button:focus-visible,
.cta:focus-visible,
.nav-link:focus-visible,
.menu-toggle:focus-visible,
.language-button:focus-visible {
  outline: 3px solid var(--color-warning);
  outline-offset: 3px;
}

.button-primary,
.cta-primary {
  color: var(--color-white);
  border-color: var(--color-success);
  background: var(--color-success);
  box-shadow: var(--shadow-button), 4px 4px 0 var(--color-accent-dark);
}

.button-primary:hover,
.cta-primary:hover {
  color: var(--color-white);
}

.button-secondary,
.cta-secondary {
  box-shadow: 4px 4px 0 var(--color-panel-secondary);
}

.button-accent {
  color: var(--color-white);
  border-color: var(--color-accent-dark);
  background: var(--color-accent);
  box-shadow: 4px 4px 0 var(--color-accent-dark);
}

.button[disabled],
.button.is-disabled {
  cursor: not-allowed;
  opacity: 0.48;
  transform: none;
  box-shadow: none;
}

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

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

.paper-card {
  padding: clamp(22px, 3vw, 38px);
}

.paper-card.is-tilted,
.tilt {
  transform: rotate(0.35deg);
}

.site-header {
  position: relative;
  z-index: 90;
  height: var(--header-height);
  border-bottom: 1px solid var(--color-border-soft);
  background: var(--color-paper-soft);
  backdrop-filter: blur(12px);
}

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

.header-inner {
  width: min(calc(100% - 48px), var(--page-width));
  height: 100%;
  margin-inline: auto;
  display: grid;
  grid-template-columns: 190px minmax(0, 1fr) auto;
  align-items: center;
  gap: 18px;
}

.brand {
  width: max-content;
  display: inline-flex;
  align-items: center;
  gap: 11px;
  color: var(--color-text);
  text-decoration: none;
}

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

.brand-logo {
  width: 39px;
  height: 39px;
  flex: 0 0 auto;
  border-radius: var(--radius-md);
  box-shadow: 0 6px 14px var(--color-accent-glow);
  transform: rotate(-2deg);
}

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

.brand-latin {
  font-family: var(--font-display);
  font-size: 22px;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.brand-local {
  color: var(--color-text-muted);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.06em;
}

.primary-nav {
  min-width: 0;
}

.primary-nav ul {
  margin: 0;
  padding: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1px;
  list-style: none;
}

.nav-link {
  min-height: 50px;
  padding: 7px 8px;
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 4px;
  position: relative;
  color: var(--color-text-muted);
  border-radius: var(--radius-sm);
  font-size: 11px;
  font-weight: 600;
  line-height: 1.2;
  text-decoration: none;
  white-space: nowrap;
  transition: color 180ms ease, background-color 180ms ease;
}

.nav-link svg {
  width: 16px;
  height: 16px;
  flex: 0 0 auto;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.7;
}

.nav-link::after {
  position: absolute;
  right: 10px;
  bottom: 2px;
  left: 10px;
  height: 2px;
  content: "";
  background: var(--color-accent);
  transform: scaleX(0);
  transform-origin: center;
  transition: transform 180ms ease;
}

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

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

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

.language-switcher {
  position: relative;
}

.language-button,
.login-button,
.menu-toggle {
  min-height: 38px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.language-button {
  padding: 0 10px;
  gap: 6px;
  color: var(--color-text-muted);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xs);
  background: var(--color-panel);
  font-size: 11px;
  font-weight: 600;
  white-space: nowrap;
}

.language-button svg,
.login-button svg {
  width: 15px;
  height: 15px;
  flex: 0 0 auto;
  fill: none;
  stroke: currentColor;
}

.language-menu {
  min-width: 168px;
  margin: 0;
  padding: 7px;
  display: none;
  position: absolute;
  top: calc(100% + 10px);
  right: 0;
  z-index: 120;
  border: 1px solid var(--color-border);
  background: var(--color-panel);
  box-shadow: var(--shadow-navigation);
  list-style: none;
}

.language-switcher.is-open .language-menu {
  display: block;
}

.language-menu a {
  min-height: 42px;
  padding: 9px 11px;
  display: flex;
  align-items: center;
  color: var(--color-text-muted);
  text-decoration: none;
}

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

.login-button {
  padding: 0 16px;
  gap: 7px;
  color: var(--color-panel);
  border: 1px solid var(--color-accent-dark);
  border-radius: var(--radius-xs);
  background: var(--color-text);
  box-shadow: 3px 3px 0 var(--color-border);
  font-size: 12px;
  font-weight: 700;
  text-decoration: none;
  white-space: nowrap;
}

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

.menu-toggle {
  display: none;
  min-width: 44px;
  min-height: 44px;
  padding: 0;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xs);
  background: var(--color-panel);
}

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

.mobile-nav {
  display: none;
}

.nav-veil {
  display: none;
}

.site-footer {
  position: relative;
  overflow-x: clip;
  color: var(--color-panel-secondary);
  border-top: 5px solid var(--color-accent);
  background: var(--color-text);
}

.footer-inner {
  padding-top: 68px;
  padding-bottom: 30px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.25fr 1fr 1.4fr 0.9fr;
  gap: 46px;
}

.footer-brand .brand {
  color: var(--color-panel);
}

.footer-brand p {
  max-width: 30rem;
  margin-top: 20px;
  color: var(--color-border);
}

.footer-heading {
  margin-bottom: 18px;
  color: var(--color-panel);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

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

.footer-links {
  columns: 2;
  column-gap: 20px;
}

.footer-links li,
.footer-languages li {
  margin-bottom: 9px;
  break-inside: avoid;
}

.footer-links a,
.footer-languages a,
.footer-keywords a {
  color: var(--color-border);
  text-decoration: none;
}

.footer-links a:hover,
.footer-languages a:hover,
.footer-keywords a:hover {
  color: var(--color-panel);
}

.footer-keywords {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.footer-keywords a {
  max-width: 100%;
  padding: 6px 9px;
  overflow: hidden;
  display: block;
  border: 1px solid var(--color-text-muted);
  border-radius: var(--radius-xs);
  font-size: 0.78rem;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.footer-bottom {
  margin-top: 46px;
  padding-top: 22px;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 16px;
  color: var(--color-border);
  border-top: 1px solid var(--color-text-muted);
  font-family: var(--font-mono);
  font-size: 0.72rem;
}

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

.footer-legal a {
  color: inherit;
}

.reveal {
  transition: opacity 700ms var(--ease-soft), transform 700ms var(--ease-soft);
}

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

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

.prose {
  font-size: 1.04rem;
}

.prose > * {
  max-width: 100%;
}

.prose h2 {
  margin-top: 2.5em;
  scroll-margin-top: calc(var(--toc-offset) + var(--toc-height) + 20px);
}

.prose h3 {
  margin-top: 2em;
}

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

.prose li::marker {
  color: var(--color-accent);
  font-weight: 700;
}

.prose img {
  height: auto;
  margin: 30px auto;
  border: 1px solid var(--color-border);
}

body:has(.toc-tabs) section[id] {
  scroll-margin-top: calc(var(--toc-offset) + var(--toc-height) + 20px);
}

@media (max-width: 1260px) {
  .header-inner {
    width: calc(100% - 30px);
    grid-template-columns: 164px minmax(0, 1fr) auto;
    gap: 8px;
  }

  .brand-local {
    display: none;
  }

  .nav-link {
    padding-inline: 5px;
    font-size: 10px;
  }
}

@media (max-width: 1080px) {
  :root {
    --header-height: 72px;
  }

  .header-inner {
    width: 100%;
    padding-inline: var(--gutter);
    display: flex;
  }

  .primary-nav,
  .language-switcher > .language-button,
  .language-switcher > .language-menu {
    display: none;
  }

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

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

  .nav-veil {
    display: block;
    position: fixed;
    inset: var(--header-height) 0 0;
    z-index: 78;
    visibility: hidden;
    opacity: 0;
    background: var(--color-shadow-deep);
    transition: opacity 180ms ease, visibility 180ms ease;
  }

  .nav-veil.is-open {
    visibility: visible;
    opacity: 1;
  }

  .mobile-nav {
    width: min(430px, 100%);
    max-height: calc(100dvh - var(--header-height));
    padding: 12px var(--gutter) 24px;
    display: block;
    position: fixed;
    top: var(--header-height);
    right: 0;
    z-index: 100;
    overflow-y: auto;
    overscroll-behavior: contain;
    visibility: hidden;
    opacity: 0;
    border-left: 1px solid var(--color-border);
    border-bottom: 1px solid var(--color-border);
    background: var(--color-panel);
    box-shadow: var(--shadow-navigation);
    transform: none;
    transition: opacity 180ms ease, visibility 180ms ease;
  }

  .mobile-nav.is-open {
    visibility: visible;
    opacity: 1;
    transform: none;
  }

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

  .mobile-nav a {
    width: 100%;
    min-height: 48px;
    padding: 12px 10px;
    display: flex;
    align-items: center;
    gap: 12px;
    color: var(--color-text);
    border-bottom: 1px solid var(--color-border-soft);
    text-decoration: none;
  }

  .mobile-nav a svg {
    width: 19px;
    height: 19px;
    flex: 0 0 auto;
    fill: none;
    stroke: currentColor;
  }

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

  .mobile-language-heading {
    margin: 20px 10px 6px;
    color: var(--color-text-muted);
    font-family: var(--font-mono);
    font-size: 0.7rem;
    letter-spacing: 0.08em;
  }

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

@media (max-width: 768px) {
  h1,
  .hero-title {
    font-size: clamp(28px, 9.5vw, 40px);
    line-height: 1.12;
    letter-spacing: -0.015em;
  }

  h2 {
    font-size: clamp(29px, 8vw, 40px);
  }

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

  .paper-card.is-tilted,
  .tilt {
    transform: none;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 34px;
  }

  .footer-links {
    columns: 1;
  }

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

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

  .brand-logo {
    width: 36px;
    height: 36px;
  }

  .brand-latin {
    font-size: 20px;
  }

  .login-button {
    min-width: 44px;
    padding-inline: 11px;
  }

  .login-button span {
    display: none;
  }

  .button-row,
  .hero-actions {
    align-items: stretch;
  }

  .button-row .button,
  .hero-actions .cta {
    flex: 1 1 150px;
  }

  .paper-card,
  .panel {
    transform: none;
  }

  .prose > .data-table {
    width: 100%;
    min-width: 0;
    max-width: 100%;
    display: block;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
  }

  .decorative-word,
  .section-number,
  .hero-coordinate {
    display: none !important;
  }
}

@media (max-width: 360px) {
  .header-inner {
    gap: 5px;
  }

  .brand {
    gap: 7px;
  }

  .header-tools {
    gap: 5px;
  }
}

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

  *,
  *::before,
  *::after {
    animation: none !important;
    transition: none !important;
  }

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