:root {
  --color-bg: #111214;
  --color-panel: #17181B;
  --color-panel-raised: #1E2024;
  --color-border: #2A2C31;
  --color-accent: #FF6D5E;
  --color-accent-dark: #D94A3D;
  --color-text: #F2F0EB;
  --color-text-muted: #9B9A94;
  --color-success: #5FBF8A;
  --color-warning: #E5B35A;
  --color-error: #E36055;
  --color-globe-line: #DAD7CD;
  --color-flag-red: #C8463C;
  --color-flag-navy: #2E4380;
  --color-flag-white: #F4F2EC;
  --color-flag-blue: #31578D;
  --color-focus-shadow: rgb(255 109 94 / 28%);
  --color-accent-shadow: rgb(255 109 94 / 22%);
  --color-accent-shadow-strong: rgb(255 109 94 / 34%);
  --color-panel-shadow: rgb(0 0 0 / 24%);
  --color-overlay: rgb(17 18 20 / 88%);
  --color-transparent: rgb(0 0 0 / 0%);
  --gradient-accent: linear-gradient(135deg, var(--color-accent), var(--color-accent-dark));
  --gradient-hero: radial-gradient(circle at 28% 46%, var(--color-accent-shadow), var(--color-transparent) 34%);
  --font-display: 'Inter', 'Noto Sans SC', 'Noto Sans JP', 'Noto Sans KR', 'PingFang SC', 'Hiragino Sans', 'Microsoft YaHei', sans-serif;
  --font-body: 'Inter', 'Noto Sans SC', 'Noto Sans JP', 'Noto Sans KR', 'PingFang SC', 'Hiragino Sans', 'Microsoft YaHei', sans-serif;
  --font-mono: 'JetBrains Mono', 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, monospace;
  --radius-small: 6px;
  --radius-medium: 10px;
  --radius-large: 16px;
  --radius-pill: 999px;
  --header-height: 76px;
  --content-width: 1280px;
  --reading-width: 780px;
  --gutter: 48px;
  --section-space: 104px;
  --shadow-panel: 0 24px 70px var(--color-panel-shadow);
  --shadow-accent: 0 12px 34px var(--color-accent-shadow);
  --transition-fast: 180ms ease;
  --transition-reveal: 620ms cubic-bezier(.2, .75, .25, 1);
  --toc-offset: 98px;
}

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

html {
  min-width: 320px;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-height) + 16px);
  background: var(--color-bg);
}

html.nav-open {
  overflow: hidden;
}

body {
  min-width: 320px;
  min-height: 100vh;
  margin: 0;
  overflow-x: clip;
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.72;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

body::before {
  position: fixed;
  z-index: 20;
  inset: 0;
  pointer-events: none;
  content: "";
  opacity: .04;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='140' height='140'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.85' numOctaves='2' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='140' height='140' filter='url(%23n)'/%3E%3C/svg%3E");
}

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

img {
  height: auto;
}

svg {
  flex-shrink: 0;
}

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

button {
  border: 0;
}

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

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

p {
  margin-bottom: 1.25em;
}

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

li + li {
  margin-top: .45em;
}

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

h1 {
  margin-bottom: 24px;
  font-size: clamp(52px, 5vw, 64px);
  font-weight: 800;
  letter-spacing: -.01em;
  line-height: 1.14;
}

h2 {
  margin-bottom: 20px;
  font-size: clamp(34px, 3.4vw, 48px);
  font-weight: 800;
  letter-spacing: -.01em;
  line-height: 1.18;
}

h3 {
  margin-bottom: 12px;
  font-size: clamp(21px, 2vw, 28px);
  font-weight: 750;
  line-height: 1.28;
}

h4 {
  margin-bottom: 10px;
  font-size: 18px;
  line-height: 1.35;
}

strong {
  color: var(--color-text);
}

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

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

:not(pre) > code {
  padding: .12em .4em;
  overflow-wrap: anywhere;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-small);
  background: var(--color-panel);
  color: var(--color-text);
  font-size: .88em;
}

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

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

hr {
  margin: 40px 0;
  border: 0;
  border-top: 1px solid var(--color-border);
}

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

a:focus-visible,
button:focus-visible,
summary:focus-visible,
[role="tab"]:focus-visible,
input:focus-visible,
select:focus-visible,
textarea:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 3px;
}

.wrap {
  width: 100%;
  max-width: var(--content-width);
  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: 64px;
  padding-bottom: 64px;
  overflow-x: clip;
}

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

.eyebrow {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 18px;
  color: var(--color-text-muted);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .14em;
  text-transform: uppercase;
}

.eyebrow-dot,
.status-dot {
  width: 7px;
  height: 7px;
  flex: 0 0 auto;
  border-radius: var(--radius-pill);
  background: var(--color-accent);
  box-shadow: 0 0 12px var(--color-accent);
}

.section-heading {
  max-width: 760px;
  margin-bottom: 42px;
}

.section-heading p {
  max-width: 680px;
  margin-bottom: 0;
  color: var(--color-text-muted);
  font-size: 18px;
}

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

.btn {
  min-height: 48px;
  padding: 13px 28px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 9px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-medium);
  cursor: pointer;
  font-family: var(--font-display);
  font-size: 15px;
  font-weight: 750;
  line-height: 1.2;
  transition: transform var(--transition-fast), border-color var(--transition-fast), background var(--transition-fast), box-shadow var(--transition-fast);
}

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

.btn-primary,
.btn-main {
  border-color: var(--color-accent);
  background: var(--gradient-accent);
  color: var(--color-bg);
  box-shadow: 0 0 0 1px var(--color-focus-shadow), var(--shadow-accent);
}

.btn-primary:hover,
.btn-main:hover {
  box-shadow: 0 0 0 1px var(--color-accent), 0 15px 40px var(--color-accent-shadow-strong);
}

.btn-secondary,
.btn-ghost {
  background: var(--color-panel);
  color: var(--color-text);
}

.btn-secondary:hover,
.btn-ghost:hover {
  border-color: var(--color-text-muted);
  background: var(--color-panel-raised);
}

.btn-small {
  min-height: 40px;
  padding: 9px 18px;
  font-size: 14px;
}

.btn[aria-disabled="true"],
.btn:disabled {
  cursor: not-allowed;
  opacity: .52;
  transform: none;
}

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

.panel {
  padding: 30px;
}

.card {
  padding: 26px;
  transition: transform var(--transition-fast), border-color var(--transition-fast), background var(--transition-fast);
}

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

.card p:last-child,
.panel p:last-child {
  margin-bottom: 0;
}

.site-head {
  position: relative;
  z-index: 40;
  border-bottom: 1px solid var(--color-border);
  background: var(--color-bg);
}

.head-in {
  min-height: var(--header-height);
  display: flex;
  align-items: center;
  gap: 26px;
}

.brand {
  min-width: max-content;
  display: inline-flex;
  align-items: center;
  gap: 10px;
}

.brand-logo {
  width: 32px;
  height: 32px;
  display: block;
}

.brand-name {
  font-family: var(--font-display);
  font-size: 19px;
  font-weight: 800;
  letter-spacing: .02em;
}

.brand-local {
  color: var(--color-text-muted);
  font-weight: 600;
}

.main-nav {
  margin-left: auto;
  display: flex;
  align-items: center;
  gap: 13px;
  color: var(--color-text-muted);
  font-size: 13px;
  white-space: nowrap;
}

.main-nav a {
  min-height: 28px;
  display: inline-flex;
  align-items: center;
  padding: 2px;
  transition: color var(--transition-fast);
}

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

.main-nav a.on,
.main-nav a[aria-current="page"] {
  font-weight: 700;
}

.nav-separator {
  color: var(--color-border);
  user-select: none;
}

.header-tools {
  display: flex;
  align-items: center;
  gap: 10px;
}

.login-btn {
  min-height: 38px;
  padding: 8px 19px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-pill);
  background: var(--color-panel);
  font-size: 13px;
  font-weight: 700;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.login-btn:hover {
  border-color: var(--color-accent-dark);
  box-shadow: 0 0 0 1px var(--color-focus-shadow);
}

.language-picker {
  position: relative;
}

.language-button {
  min-width: 40px;
  min-height: 38px;
  padding: 6px 9px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 5px;
  border-radius: var(--radius-small);
  background: transparent;
  color: var(--color-text-muted);
  cursor: pointer;
  font-size: 13px;
}

.language-menu {
  position: absolute;
  top: calc(100% + 10px);
  right: 0;
  width: 166px;
  padding: 7px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-medium);
  background: var(--color-panel-raised);
  box-shadow: var(--shadow-panel);
}

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

.language-menu a {
  min-height: 40px;
  padding: 8px 11px;
  display: flex;
  align-items: center;
  border-radius: var(--radius-small);
  color: var(--color-text-muted);
  font-size: 14px;
}

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

.menu-toggle {
  width: 44px;
  min-width: 44px;
  height: 44px;
  min-height: 44px;
  padding: 11px;
  display: none;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-small);
  background: transparent;
  color: var(--color-text);
  cursor: pointer;
}

.menu-toggle svg {
  width: 22px;
  height: 22px;
}

.mobile-nav {
  display: none;
}

.nav-veil {
  display: none;
}

.site-footer {
  position: relative;
  z-index: 2;
  border-top: 1px solid var(--color-border);
  background: var(--color-panel);
}

.footer-grid {
  padding-top: 68px;
  padding-bottom: 48px;
  display: grid;
  grid-template-columns: 1.25fr 1fr 1.15fr .8fr;
  gap: 44px;
}

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

.footer-heading {
  margin-bottom: 16px;
  color: var(--color-text);
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .12em;
  text-transform: uppercase;
}

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

.footer-links li + li {
  margin-top: 8px;
}

.footer-links a {
  min-height: 28px;
  display: inline-flex;
  align-items: center;
  color: var(--color-text-muted);
  font-size: 14px;
  transition: color var(--transition-fast);
}

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

.footer-bottom {
  min-height: 70px;
  padding-top: 18px;
  padding-bottom: 18px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 22px;
  border-top: 1px solid var(--color-border);
  color: var(--color-text-muted);
  font-size: 13px;
}

.footer-legal {
  display: flex;
  flex-wrap: wrap;
  gap: 18px;
}

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

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

.reveal.shown {
  opacity: 1;
  transform: translateY(0);
}

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

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

.prose h3 {
  margin-top: 1.8em;
}

.prose a {
  color: var(--color-accent);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: .2em;
}

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

.prose table {
  width: 100%;
}

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

@media (max-width: 1120px) {
  :root {
    --gutter: 30px;
  }

  .main-nav {
    gap: 8px;
    font-size: 12px;
  }

  .nav-separator {
    display: none;
  }

  .footer-grid {
    grid-template-columns: 1.25fr 1fr 1fr;
  }

  .footer-language {
    grid-column: 2 / -1;
  }
}

@media (max-width: 900px) {
  .main-nav,
  .language-picker {
    display: none;
  }

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

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

  .nav-veil {
    position: fixed;
    z-index: 38;
    inset: var(--header-height) 0 0;
    display: block;
    background: var(--color-overlay);
  }

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

  .mobile-nav {
    position: absolute;
    z-index: 41;
    top: 100%;
    right: 0;
    left: 0;
    max-height: calc(100dvh - var(--header-height));
    padding: 10px var(--gutter) 20px;
    overflow-y: auto;
    overscroll-behavior: contain;
    border-bottom: 1px solid var(--color-border);
    background: var(--color-panel);
  }

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

  .mobile-nav a {
    width: 100%;
    min-height: 46px;
    padding: 11px 8px;
    display: flex;
    align-items: center;
    border-bottom: 1px solid var(--color-border);
    color: var(--color-text-muted);
  }

  .mobile-nav a.on {
    color: var(--color-text);
    font-weight: 700;
  }

  .mobile-language-title {
    margin: 18px 8px 4px;
    color: var(--color-text-muted);
    font-family: var(--font-mono);
    font-size: 11px;
    letter-spacing: .12em;
  }

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

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

@media (max-width: 768px) {
  :root {
    --gutter: 20px;
    --section-space: 76px;
  }

  h1 {
    font-size: clamp(34px, 9.3vw, 40px);
    line-height: 1.14;
  }

  h2 {
    font-size: clamp(28px, 7.8vw, 36px);
  }

  .section-heading p {
    font-size: 16px;
  }

  .footer-grid {
    gap: 34px 24px;
  }

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

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

  .head-in {
    gap: 10px;
  }

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

  .brand-local {
    display: none;
  }

  .login-btn {
    min-width: 58px;
    padding-inline: 13px;
  }

  .panel,
  .card {
    padding: 21px;
  }

  .btn {
    width: 100%;
  }

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

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

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

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

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

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