:root {
  --color-surface: #f3f2f2;
  --color-surface-alt: #ebe9e9;
  --color-surface-deep: #dfdddc;
  --color-ink: #4c423e;
  --color-ink-soft: #756762;
  --color-ink-muted: #8a7b75;
  --color-line: #d5d2d2;
  --color-primary: #ac6244;
  --color-primary-ink: #ffffff;
  --color-primary-soft: #e9deda;
  --color-accent: #227ea5;
  --color-accent-ink: #ffffff;
  --color-highlight: #cddde4;
  --color-focus: #16759d;
  --color-contrast-surface: #1a1412;
  --color-contrast-ink: #e7e5e4;
  --color-contrast-line: #474240;
  --color-contrast-accent: #2ca2d3;
  --overlay-scrim: linear-gradient(180deg, rgba(26, 20, 18, 0.35) 0%, rgba(26, 20, 18, 0.72) 55%, rgba(26, 20, 18, 0.92) 100%);
  --font-heading: "Songti SC", "Source Han Serif SC", "Noto Serif SC", SimSun, serif;
  --font-body: "PingFang SC", "Microsoft YaHei", "Source Han Sans SC", sans-serif;
  --font-mono: ui-monospace, Menlo, Consolas, monospace;
  --text-xs: 11.4px;
  --text-sm: 14.3px;
  --text-base: 16px;
  --text-lg: 20.0px;
  --text-xl: 25.0px;
  --text-2xl: 31.2px;
  --text-3xl: 39.1px;
  --text-4xl: 48.8px;
  --text-display: clamp(35px, 7.2vw, 92px);
  --text-figure: clamp(29px, 5.2vw, 66px);
  --weight-heading: 621;
  --weight-body: 400;
  --leading-body: 1.8;
  --leading-heading: 1.17;
  --tracking-heading: -0.004em;
  --radius-sm: 1px;
  --radius-md: 2px;
  --radius-lg: 2px;
  --radius-pill: 2px;
  --border-thin: 1px;
  --border-thick: 1px;
  --shadow-1: none;
  --shadow-2: none;
  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 32px;
  --space-6: 48px;
  --space-8: 64px;
  --container: 1120px;
  --measure: 65ch;
  --gutter: 24px;
  --section-y: 78px;
  --section-y-lg: 109px;
}

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

html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }

body {
  margin: 0;
  background-color: var(--color-surface);
  background-image: repeating-linear-gradient(
    0deg,
    color-mix(in srgb, var(--color-ink) 2.4%, transparent) 0 1px,
    transparent 1px 4px
  );
  color: var(--color-ink);
  font-family: var(--font-body);
  font-size: var(--text-base);
  font-weight: var(--weight-body);
  line-height: var(--leading-body);
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

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

a { color: var(--color-accent); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 3px; }

button { font: inherit; color: inherit; }

ul, ol { margin: 0; padding: 0; list-style: none; }

p { margin: 0; }

hr { border: 0; margin: 0; }

:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

/* ============ 排版基座 ============ */
h1, h2, h3, h4, h5, h6 {
  margin: 0;
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
}

.mono {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.02em;
}

/* ============ 布局 ============ */
.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.grid-12 {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: var(--gutter);
}

.split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--space-4);
}

.split__main { min-width: 0; }
.split__rail { min-width: 0; }

.section {
  padding-block: var(--section-y);
  position: relative;
}

.section--alt { background: var(--color-surface-alt); }

.section--contrast {
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}

.section--contrast h1,
.section--contrast h2,
.section--contrast h3,
.section--contrast h4 { color: var(--color-contrast-ink); }

.section__title {
  font-size: var(--text-3xl);
  max-width: 22ch;
}

/* ============ 通用组件 ============ */
.press-label {
  display: inline-block;
  font-family: var(--font-body);
  font-size: var(--text-xs);
  font-weight: 600;
  line-height: 1.3;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--color-primary-ink);
  background: var(--color-primary);
  padding: 5px 9px 4px;
  border-radius: var(--radius-sm);
}

.press-label--ink {
  background: transparent;
  color: var(--color-primary);
  padding-inline: 0;
}

.press-label--contrast {
  background: transparent;
  color: var(--color-contrast-accent);
  padding-inline: 0;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: 12px 22px;
  border: var(--border-thin) solid var(--color-ink-soft);
  border-radius: var(--radius-sm);
  background: transparent;
  color: var(--color-ink);
  font-family: var(--font-body);
  font-size: var(--text-sm);
  font-weight: 600;
  letter-spacing: 0.12em;
  text-decoration: none;
  cursor: pointer;
  transition: background-color 0.18s ease, color 0.18s ease, border-color 0.18s ease;
}

.btn:hover {
  background: var(--color-contrast-surface);
  border-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  text-decoration: none;
}

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

.btn--primary:hover {
  background: color-mix(in srgb, var(--color-primary) 78%, var(--color-contrast-surface));
  border-color: color-mix(in srgb, var(--color-primary) 78%, var(--color-contrast-surface));
  color: var(--color-primary-ink);
}

.btn--ghost {
  border-color: var(--color-line);
  color: var(--color-ink-soft);
}

.btn--ghost:hover {
  background: transparent;
  border-color: var(--color-accent);
  color: var(--color-accent);
}

.btn--on-dark {
  border-color: var(--color-contrast-line);
  color: var(--color-contrast-ink);
}

.btn--on-dark:hover {
  background: var(--color-contrast-ink);
  border-color: var(--color-contrast-ink);
  color: var(--color-contrast-surface);
}

.rule-double {
  position: relative;
  height: 4px;
  border-top: var(--border-thin) solid var(--color-line);
}

.rule-double::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  top: 3px;
  border-top: var(--border-thin) solid var(--color-line);
}

.rule-double--contrast { border-top-color: var(--color-contrast-line); }
.rule-double--contrast::after { border-top-color: var(--color-contrast-line); }

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-1);
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  color: var(--color-ink-muted);
}

.breadcrumb a {
  color: var(--color-ink-soft);
  border-bottom: var(--border-thin) solid var(--color-line);
}

.breadcrumb a:hover {
  color: var(--color-accent);
  border-bottom-color: var(--color-accent);
  text-decoration: none;
}

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

.prose {
  max-width: var(--measure);
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: var(--color-ink);
}

.prose p + p { margin-top: 1.15em; }
.prose h2 { font-size: var(--text-2xl); margin-top: 1.6em; margin-bottom: 0.5em; }
.prose h3 { font-size: var(--text-xl); margin-top: 1.4em; margin-bottom: 0.4em; }
.prose ul, .prose ol { margin: 1em 0 0; padding-left: 1.35em; }
.prose ul { list-style: square; }
.prose ol { list-style: decimal; }
.prose li { margin-top: 0.45em; }
.prose strong { font-weight: 600; color: var(--color-ink); }
.prose a { border-bottom: var(--border-thin) solid var(--color-accent); }

.sidenote {
  font-size: var(--text-sm);
  line-height: 1.75;
  color: var(--color-ink-soft);
  border-top: 2px solid var(--color-primary);
  padding-top: var(--space-2);
}

.sidenote cite {
  display: block;
  margin-top: var(--space-2);
  font-style: normal;
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  color: var(--color-ink-muted);
}

/* ============ 图片容器 ============ */
.figure {
  margin: 0;
  min-width: 0;
}

.figure__frame {
  position: relative;
  overflow: hidden;
  background: var(--color-surface-deep);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
}

.figure__frame img,
.figure__placeholder {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.figure__placeholder {
  min-height: 140px;
  background-color: var(--color-surface-deep);
  background-image:
    linear-gradient(135deg,
      color-mix(in srgb, var(--color-accent) 18%, transparent) 0%,
      transparent 58%),
    repeating-linear-gradient(90deg,
      color-mix(in srgb, var(--color-ink) 5%, transparent) 0 1px,
      transparent 1px 14px);
}

.figure__caption {
  margin-top: var(--space-1);
  font-size: var(--text-xs);
  line-height: 1.6;
  letter-spacing: 0.04em;
  color: var(--color-ink-muted);
}

.figure--scrim .figure__frame::after {
  content: "";
  position: absolute;
  inset: 0;
  background: var(--overlay-scrim);
  pointer-events: none;
}

.figure--wide .figure__frame { aspect-ratio: 16 / 9; }
.figure--tall .figure__frame { aspect-ratio: 3 / 4; }
.figure--square .figure__frame { aspect-ratio: 1 / 1; }
.figure--slim .figure__frame { aspect-ratio: 21 / 9; }

/* ============ 显现协议 ============ */
[data-reveal] {
  transition: opacity 0.55s ease, transform 0.55s ease;
}

html.js [data-reveal] {
  opacity: 0;
  transform: translateY(14px);
}

html.js [data-reveal][data-revealed] {
  opacity: 1;
  transform: translateY(0);
}

/* ============ 跳至主要内容 ============ */
.skip-link {
  position: absolute;
  left: var(--space-2);
  top: -80px;
  z-index: 90;
  padding: 10px 16px;
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  font-size: var(--text-sm);
  letter-spacing: 0.08em;
  border-radius: var(--radius-sm);
  transition: top 0.18s ease;
}

.skip-link:focus {
  top: var(--space-2);
  text-decoration: none;
}

/* ============ 头部 ============ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--color-surface);
  border-bottom: var(--border-thin) solid var(--color-line);
}

.site-header__strip {
  background: var(--color-surface-deep);
  border-bottom: var(--border-thin) solid var(--color-line);
}

.site-header__strip-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  min-height: 30px;
  padding-block: 4px;
}

.site-header__strip-meta {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  color: var(--color-ink-muted);
}

.site-header__tick {
  display: inline-block;
  width: 4px;
  height: 4px;
  background: var(--color-primary);
  transform: rotate(45deg);
}

.site-header__bar {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  padding-block: var(--space-2);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  color: var(--color-ink);
  text-decoration: none;
  min-width: 0;
}

.brand:hover { text-decoration: none; }

.brand__mark {
  flex: none;
  font-family: var(--font-mono);
  font-size: var(--text-lg);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.03em;
  padding: 9px 7px 8px;
  background: var(--color-primary);
  color: var(--color-primary-ink);
  border-radius: var(--radius-sm);
}

.brand__lockup { display: block; min-width: 0; }

.brand__name {
  display: block;
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-xl);
  line-height: 1.06;
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
}

.brand__tag {
  display: block;
  margin-top: 3px;
  font-size: var(--text-xs);
  letter-spacing: 0.22em;
  color: var(--color-ink-muted);
}

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

.site-nav__list {
  display: flex;
  align-items: center;
  gap: 2px;
}

.site-nav__list a {
  display: block;
  padding: 7px 11px;
  font-size: var(--text-sm);
  font-weight: 500;
  letter-spacing: 0.1em;
  color: var(--color-ink-soft);
  border-radius: var(--radius-sm);
  border-bottom: 2px solid transparent;
  transition: color 0.18s ease, background-color 0.18s ease, border-color 0.18s ease;
}

.site-nav__list a:hover {
  color: var(--color-ink);
  border-bottom-color: var(--color-line);
  text-decoration: none;
}

.site-nav__list a[aria-current="page"] {
  background: var(--color-primary);
  color: var(--color-primary-ink);
  border-bottom-color: transparent;
  font-weight: 600;
}

.site-nav__list a[aria-current="page"]:hover {
  background: color-mix(in srgb, var(--color-primary) 80%, var(--color-contrast-surface));
  color: var(--color-primary-ink);
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: var(--space-1);
  padding: 9px 12px;
  background: transparent;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  color: var(--color-ink-soft);
  font-size: var(--text-xs);
  letter-spacing: 0.14em;
  cursor: pointer;
}

.nav-toggle__bars {
  display: block;
  width: 16px;
  height: 9px;
  border-top: 1px solid currentColor;
  border-bottom: 1px solid currentColor;
  position: relative;
}

.nav-toggle__bars::after {
  content: "";
  position: absolute;
  left: 0;
  top: 3px;
  width: 16px;
  border-top: 1px solid currentColor;
}

.nav-toggle[aria-expanded="true"] {
  color: var(--color-primary);
  border-color: var(--color-primary);
}

.nav-toggle__label { line-height: 1; }

/* ============ 页脚 ============ */
.site-footer {
  margin-top: var(--section-y-lg);
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  padding-top: var(--space-8);
  overflow: hidden;
}

.site-footer h2 { color: var(--color-contrast-ink); }

.site-footer__index {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--space-6);
  padding-block: var(--space-8) var(--space-6);
}

.site-footer__lead { min-width: 0; }

.site-footer__closing {
  margin-top: var(--space-3);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-xl);
  line-height: 1.5;
  letter-spacing: var(--tracking-heading);
  color: var(--color-contrast-ink);
  max-width: 20ch;
}

.site-footer__cols {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--space-4) var(--space-3);
}

.site-footer__col { min-width: 0; }

.site-footer__col-title {
  font-family: var(--font-body);
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--color-contrast-accent);
  padding-bottom: var(--space-1);
  border-bottom: var(--border-thin) solid var(--color-contrast-line);
}

.site-footer__links { margin-top: var(--space-2); }

.site-footer__links li + li { margin-top: 6px; }

.site-footer__links a {
  color: color-mix(in srgb, var(--color-contrast-ink) 76%, transparent);
  font-size: var(--text-sm);
  letter-spacing: 0.06em;
}

.site-footer__links a:hover {
  color: var(--color-contrast-accent);
  text-decoration: none;
}

.site-footer__meta {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 6px;
  padding-block: var(--space-4);
  border-top: var(--border-thin) solid var(--color-contrast-line);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  color: color-mix(in srgb, var(--color-contrast-ink) 62%, transparent);
}

.site-footer__contact {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-1);
  color: var(--color-contrast-ink);
}

.site-footer__dot { color: var(--color-contrast-line); }

.site-footer__legal {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-1);
}

.site-footer__wordmark {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: clamp(44px, 17vw, 196px);
  line-height: 0.9;
  letter-spacing: -0.03em;
  text-align: center;
  white-space: nowrap;
  user-select: none;
  padding: var(--space-2) var(--gutter) var(--space-3);
  color: color-mix(in srgb, var(--color-contrast-ink) 17%, transparent);
}

/* ============ 滚动 UI ============ */
.progress-bar {
  position: fixed;
  top: 0;
  left: 0;
  width: 0;
  height: 2px;
  z-index: 80;
  background: var(--color-primary);
  pointer-events: none;
}

.back-to-top {
  position: fixed;
  right: var(--space-3);
  bottom: var(--space-3);
  z-index: 70;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 10px 14px;
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border: var(--border-thin) solid var(--color-contrast-line);
  border-radius: var(--radius-sm);
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.14em;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(8px);
  transition: opacity 0.25s ease, transform 0.25s ease, visibility 0.25s;
}

.back-to-top[data-visible] {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: var(--color-primary-ink);
}

.back-to-top__arrow {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  line-height: 1;
}

/* ============ 响应式 ============ */
@media (min-width: 640px) {
  .site-footer__cols { grid-template-columns: repeat(4, minmax(0, 1fr)); }
}

@media (min-width: 720px) {
  .grid-12 { grid-template-columns: repeat(12, minmax(0, 1fr)); }
}

@media (min-width: 900px) {
  .split {
    grid-template-columns: minmax(0, 1fr) 264px;
    gap: var(--space-6);
  }

  .split--reverse {
    grid-template-columns: 264px minmax(0, 1fr);
  }

  .split--reverse .split__rail { order: -1; }

  .site-footer__index {
    grid-template-columns: minmax(0, 1fr) 1.85fr;
    gap: var(--space-8);
  }

  .site-footer__meta {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: center;
    column-gap: var(--space-4);
  }

  .site-footer__contact { grid-column: 1; }
  .site-footer__address { grid-column: 1; }
  .site-footer__legal { grid-column: 2; justify-content: flex-end; }
}

@media (max-width: 1023px) {
  .site-nav__list a { padding-inline: 8px; letter-spacing: 0.06em; }
}

@media (max-width: 860px) {
  .nav-toggle { display: inline-flex; }

  .site-nav {
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    display: none;
    background: var(--color-surface);
    border-top: var(--border-thin) solid var(--color-line);
    border-bottom: var(--border-thin) solid var(--color-line);
    padding: var(--space-1) var(--gutter) var(--space-3);
  }

  .site-nav[data-open] { display: block; }

  .site-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
  }

  .site-nav__list li + li { border-top: var(--border-thin) solid var(--color-line); }

  .site-nav__list a {
    padding: 14px 2px;
    font-size: var(--text-base);
    border-bottom: 0;
    border-left: 2px solid transparent;
    border-radius: 0;
  }

  .site-nav__list a[aria-current="page"] {
    background: transparent;
    color: var(--color-primary);
    border-left-color: var(--color-primary);
    padding-left: 12px;
  }

  .site-nav__list a[aria-current="page"]:hover { background: transparent; }

  .brand__name { font-size: var(--text-lg); }
}

@media (max-width: 560px) {
  .brand__tag { display: none; }
  .site-header__strip-meta .mono:first-child { display: none; }
  .site-footer__closing { font-size: var(--text-lg); }
  .back-to-top { right: var(--space-2); bottom: var(--space-2); }
}

/* ============ 可访问性与减弱动效 ============ */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }

  html.js [data-reveal] {
    opacity: 1;
    transform: none;
  }
}