:root {
  --color-bg: #F5F0E6;
  --color-ink: #1A1A1A;
  --color-green: #0B3D2E;
  --color-green-dark: #082A20;
  --color-gold: #D4AF37;
  --color-orange: #FF6B35;
  --color-card: #FFFFFF;
  --color-border: #D1D5DB;
  --color-green-light: #E8F0E9;
  --font-headline: 'Playfair Display', Georgia, 'Times New Roman', serif;
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  --header-h: 80px;
  --container-w: 1280px;
  --space-section: 88px;
  --transition: 0.25s ease;
}

*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

body {
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-ink);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

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

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

ul,
ol {
  list-style: none;
}

button,
input,
textarea,
select {
  font: inherit;
  color: inherit;
  background: none;
  border: none;
  padding: 0;
}

:focus-visible {
  outline: 3px solid var(--color-orange);
  outline-offset: 2px;
}

::-webkit-scrollbar {
  width: 10px;
  background: var(--color-bg);
}

::-webkit-scrollbar-thumb {
  background: var(--color-green);
  border: 2px solid var(--color-bg);
}

/* ============ 布局容器 ============ */

.container {
  max-width: var(--container-w);
  margin: 0 auto;
  padding: 0 24px;
}

.container--narrow {
  max-width: 780px;
  margin: 0 auto;
  padding: 0 24px;
}

.main-content {
  min-height: 65vh;
  flex: 1;
}

/* ============ 章节编号体系 ============ */

.section {
  position: relative;
  padding: var(--space-section) 0;
  border-top: 1px solid var(--color-border);
}

.section__header {
  display: flex;
  align-items: flex-end;
  gap: 20px;
  margin-bottom: 36px;
}

.section__num {
  font-family: var(--font-headline);
  font-size: clamp(60px, 8vw, 96px);
  font-weight: 900;
  line-height: 0.9;
  color: var(--color-green);
  letter-spacing: -0.02em;
  flex: 0 0 auto;
}

.section__title {
  font-family: var(--font-headline);
  font-size: clamp(28px, 3vw, 40px);
  font-weight: 700;
  line-height: 1.15;
  color: var(--color-ink);
  margin-bottom: 6px;
}

.section__subtitle {
  font-size: 15px;
  color: var(--color-ink);
  opacity: 0.65;
  max-width: 560px;
  line-height: 1.7;
}

/* ============ 按钮 ============ */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 13px 28px;
  font-family: var(--font-body);
  font-size: 15px;
  font-weight: 600;
  line-height: 1;
  border: 1px solid transparent;
  cursor: pointer;
  transition: background-color var(--transition), color var(--transition), border-color var(--transition);
  text-decoration: none;
  white-space: nowrap;
}

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

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

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

.btn--ghost:hover {
  background: var(--color-green);
  color: var(--color-bg);
}

.btn--orange {
  background: var(--color-orange);
  color: #fff;
  border-color: var(--color-orange);
}

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

.btn--gold {
  background: var(--color-gold);
  color: var(--color-green);
  border-color: var(--color-gold);
}

.btn--gold:hover {
  background: var(--color-green);
  color: var(--color-gold);
  border-color: var(--color-gold);
}

/* ============ 标签 ============ */

.tag {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 4px 12px;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  border: 1px solid transparent;
  background: var(--color-orange);
  color: #fff;
  line-height: 1.4;
}

.tag--ghost {
  background: transparent;
  border-color: var(--color-border);
  color: var(--color-ink);
  opacity: 0.8;
}

.tag--gold {
  background: var(--color-gold);
  color: var(--color-green);
}

/* ============ 卡片 ============ */

.card {
  background: var(--color-card);
  border: 1px solid var(--color-border);
  padding: 24px;
  transition: transform var(--transition), border-color var(--transition), box-shadow var(--transition);
}

.card:hover {
  transform: translateY(-2px);
  border-color: var(--color-gold);
  box-shadow: 0 8px 24px rgba(11, 61, 46, 0.06);
}

.card--flat {
  background: transparent;
  border: none;
  padding: 0;
}

.card--green {
  background: var(--color-green);
  border-color: var(--color-green);
  color: var(--color-bg);
}

.card--green:hover {
  border-color: var(--color-gold);
}

/* ============ 网格系统 ============ */

.grid {
  display: grid;
  gap: 24px;
}

.grid--2 {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.grid--3 {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.grid--4 {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

.grid--bento {
  grid-template-columns: repeat(4, minmax(0, 1fr));
  grid-auto-rows: 170px;
  gap: 20px;
}

.bento-span-2 {
  grid-column: span 2;
}

.bento-span-3 {
  grid-column: span 3;
}

.bento-row-2 {
  grid-row: span 2;
}

/* ============ 面包屑 ============ */

.breadcrumb {
  padding: 16px 0;
  font-size: 13px;
  border-bottom: 1px solid var(--color-border);
  margin-bottom: 24px;
}

.breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
}

.breadcrumb__item {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.breadcrumb__item + .breadcrumb__item::before {
  content: '/';
  color: var(--color-border);
  font-weight: 400;
}

.breadcrumb__link {
  color: var(--color-green);
  transition: color 0.2s;
}

.breadcrumb__link:hover {
  color: var(--color-gold);
}

.breadcrumb__current {
  color: var(--color-ink);
  opacity: 0.7;
  font-weight: 500;
}

/* ============ 图片容器 ============ */

.img-mask {
  position: relative;
  overflow: hidden;
  background: var(--color-green-light);
}

.img-mask img,
.img-mask .img-placeholder {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.5s ease;
}

.img-mask:hover img,
.img-mask:hover .img-placeholder {
  transform: scale(1.04);
}

.img-mask--diagonal {
  clip-path: polygon(0 0, calc(100% - 36px) 0, 100% 36px, 100% 100%, 0 100%);
}

.img-note {
  position: absolute;
  left: 12px;
  bottom: 12px;
  z-index: 2;
  font-size: 12px;
  font-weight: 600;
  color: var(--color-bg);
  background: var(--color-green);
  padding: 6px 12px;
  border-left: 3px solid var(--color-gold);
}

.data-chip {
  display: inline-flex;
  align-items: baseline;
  gap: 4px;
  background: var(--color-green);
  color: var(--color-gold);
  border: 1px solid var(--color-green);
  padding: 6px 14px;
  font-size: 14px;
  font-weight: 600;
  line-height: 1.3;
}

/* ============ Skip Link ============ */

.skip-link {
  position: fixed;
  top: -64px;
  left: 16px;
  z-index: 9999;
  padding: 10px 20px;
  background: var(--color-orange);
  color: #fff;
  font-size: 14px;
  font-weight: 600;
  transition: top 0.2s ease;
  border: 1px solid var(--color-orange);
}

.skip-link:focus {
  top: 16px;
  color: #fff;
}

/* ============ 滚动进度条 ============ */

.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  height: 3px;
  width: 0;
  background: linear-gradient(90deg, var(--color-gold) 0%, var(--color-orange) 100%);
  z-index: 2000;
  pointer-events: none;
}

/* ============ 头部 ============ */

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: transparent;
  transition: background-color 0.3s ease, box-shadow 0.3s ease;
}

.site-header[data-scrolled="true"] {
  background: var(--color-green);
  box-shadow: 0 2px 16px rgba(8, 42, 32, 0.3);
}

.site-header__frame {
  max-width: var(--container-w);
  margin: 0 auto;
  padding: 0 24px;
  height: var(--header-h);
  display: flex;
  align-items: center;
  gap: 24px;
  position: relative;
}

/* 品牌 */

.site-brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  flex: 0 0 auto;
  position: relative;
  z-index: 20;
}

.site-brand__mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  background: var(--color-gold);
  color: var(--color-green);
  font-family: var(--font-headline);
  font-size: 22px;
  font-weight: 900;
  line-height: 1;
  clip-path: polygon(0 0, 82% 0, 100% 18%, 100% 100%, 0 100%);
}

.site-brand__text {
  font-family: var(--font-headline);
  font-size: 18px;
  font-weight: 800;
  color: var(--color-ink);
  letter-spacing: 0.02em;
  line-height: 1.2;
  white-space: nowrap;
  transition: color 0.3s ease;
}

.site-header[data-scrolled="true"] .site-brand__text {
  color: var(--color-bg);
}

/* 导航 */

.site-nav {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  position: relative;
  z-index: 10;
}

.site-nav__watermark {
  display: none;
}

.site-nav__list {
  display: flex;
  align-items: center;
  gap: 2px;
  counter-reset: nav-item;
  margin: 0;
}

.site-nav__item {
  counter-increment: nav-item;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.site-nav__item::before {
  content: "0" counter(nav-item);
  font-family: var(--font-headline);
  font-size: 11px;
  font-weight: 700;
  color: var(--color-gold);
  opacity: 0;
  letter-spacing: 0.08em;
  transition: opacity 0.2s;
}

.site-nav__link {
  display: inline-block;
  position: relative;
  padding: 8px 14px;
  font-family: var(--font-body);
  font-size: 15px;
  font-weight: 500;
  letter-spacing: 0.01em;
  color: var(--color-ink);
  transition: color 0.2s ease;
  border-bottom: 2px solid transparent;
}

.site-nav__link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 14px;
  right: 14px;
  height: 2px;
  background: var(--color-gold);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.25s ease;
}

.site-nav__link:hover {
  color: var(--color-green);
}

.site-nav__link:hover::after {
  transform: scaleX(1);
}

.site-nav__link[aria-current="page"] {
  color: var(--color-green);
}

.site-nav__link[aria-current="page"]::after {
  transform: scaleX(1);
  background: var(--color-gold);
}

.site-header[data-scrolled="true"] .site-nav__link {
  color: var(--color-bg);
}

.site-header[data-scrolled="true"] .site-nav__link:hover {
  color: var(--color-gold);
}

.site-header[data-scrolled="true"] .site-nav__link[aria-current="page"] {
  color: var(--color-gold);
}

.site-header[data-scrolled="true"] .site-nav__link::after {
  background: var(--color-gold);
}

/* CTA */

.site-nav__cta {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 22px;
  background: var(--color-orange);
  color: #fff;
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.02em;
  line-height: 1;
  border: 1px solid var(--color-orange);
  transition: background-color 0.25s ease, color 0.25s ease, border-color 0.25s ease;
}

.site-nav__cta:hover {
  background: transparent;
  color: var(--color-orange);
  border-color: var(--color-orange);
}

.site-header[data-scrolled="true"] .site-nav__cta:hover {
  color: var(--color-gold);
  border-color: var(--color-gold);
}

/* 移动端菜单按钮 */

.nav-toggle {
  display: none;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 6px;
  width: 44px;
  height: 44px;
  background: transparent;
  border: 1px solid var(--color-border);
  cursor: pointer;
  color: var(--color-ink);
  position: relative;
  z-index: 20;
  transition: color 0.2s, border-color 0.2s;
}

.nav-toggle:hover {
  border-color: var(--color-gold);
}

.nav-toggle__bar {
  display: block;
  width: 22px;
  height: 2px;
  background: currentColor;
  transition: transform 0.3s ease, opacity 0.3s ease;
}

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

.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(1) {
  transform: translateY(8px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(2) {
  opacity: 0;
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(3) {
  transform: translateY(-8px) rotate(-45deg);
}

/* ============ 页脚 ============ */

.site-footer {
  background: var(--color-green);
  color: var(--color-bg);
  border-top: 4px solid var(--color-gold);
  padding-top: 72px;
  margin-top: auto;
  position: relative;
}

.site-footer__inner {
  max-width: var(--container-w);
  margin: 0 auto;
  padding: 0 24px 48px;
  display: grid;
  grid-template-columns: 1.8fr 1fr 1fr 1fr;
  gap: 48px;
}

.site-footer__brand-col .site-brand__text {
  color: var(--color-bg);
}

.site-footer__desc {
  margin-top: 18px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--color-bg);
  opacity: 0.72;
  max-width: 360px;
}

.site-footer__col-title {
  font-family: var(--font-headline);
  font-size: 17px;
  font-weight: 700;
  color: var(--color-gold);
  letter-spacing: 0.06em;
  margin-bottom: 20px;
  padding-bottom: 10px;
  border-bottom: 1px solid rgba(212, 175, 55, 0.3);
}

.site-footer__col-list li + li {
  margin-top: 10px;
}

.site-footer__col-list a {
  display: inline-block;
  font-size: 14px;
  color: var(--color-bg);
  opacity: 0.78;
  transition: color 0.2s, opacity 0.2s, padding-left 0.2s;
  border-bottom: 1px solid transparent;
}

.site-footer__col-list a:hover {
  opacity: 1;
  color: var(--color-gold);
  padding-left: 4px;
  border-bottom-color: rgba(212, 175, 55, 0.4);
}

/* 联系条 */

.site-footer__contact {
  border-top: 1px solid rgba(245, 240, 230, 0.12);
  border-bottom: 1px solid rgba(245, 240, 230, 0.12);
  background: rgba(8, 42, 32, 0.4);
}

.site-footer__contact-inner {
  max-width: var(--container-w);
  margin: 0 auto;
  padding: 18px 24px;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 16px;
  font-size: 13px;
  color: var(--color-bg);
  opacity: 0.85;
}

.site-footer__sep {
  color: var(--color-gold);
  opacity: 0.5;
  font-size: 12px;
}

/* 底部备案 */

.site-footer__bottom {
  max-width: var(--container-w);
  margin: 0 auto;
  padding: 28px 24px 32px;
  text-align: center;
}

.site-footer__trust {
  font-size: 12px;
  line-height: 1.8;
  color: var(--color-bg);
  opacity: 0.55;
  max-width: 800px;
  margin: 0 auto 14px;
}

.site-footer__icp {
  font-size: 12px;
  color: var(--color-gold);
  opacity: 0.75;
  letter-spacing: 0.04em;
}

/* ============ 返回顶部 ============ */

.back-to-top {
  position: fixed;
  right: 24px;
  bottom: 24px;
  z-index: 950;
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-green);
  color: var(--color-gold);
  border: 1px solid var(--color-gold);
  font-size: 18px;
  line-height: 1;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(12px);
  transition: opacity 0.25s ease, transform 0.25s ease, visibility 0.25s ease, background-color 0.2s, color 0.2s;
}

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

.back-to-top:hover {
  background: var(--color-gold);
  color: var(--color-green);
}

/* ============ 页面首屏区 ============ */

.page-hero {
  padding: calc(var(--header-h) + 40px) 0 56px;
}

.page-hero__num {
  font-family: var(--font-headline);
  font-size: clamp(80px, 14vw, 140px);
  font-weight: 900;
  line-height: 0.85;
  color: transparent;
  -webkit-text-stroke: 1px rgba(11, 61, 46, 0.25);
  display: block;
  margin-bottom: 12px;
}

.page-hero__title {
  font-family: var(--font-headline);
  font-size: clamp(36px, 5vw, 64px);
  font-weight: 800;
  line-height: 1.1;
  color: var(--color-green);
  margin-bottom: 16px;
}

.page-hero__lead {
  font-size: 18px;
  line-height: 1.7;
  color: var(--color-ink);
  opacity: 0.75;
  max-width: 620px;
}

/* ============ 响应式：平板 ============ */

@media (min-width: 769px) and (max-width: 1024px) {
  :root {
    --header-h: 72px;
  }

  .site-header__frame {
    gap: 12px;
    padding: 0 20px;
  }

  .site-nav__list {
    gap: 0;
  }

  .site-nav__link {
    padding: 6px 10px;
    font-size: 14px;
  }

  .site-nav__cta {
    padding: 9px 16px;
    font-size: 13px;
  }

  .site-footer__inner {
    grid-template-columns: 1.4fr 1fr 1fr;
    gap: 32px;
  }

  .site-footer__col:last-child {
    grid-column: span 3;
  }

  .grid--4 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .grid--bento {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    grid-auto-rows: auto;
  }

  .bento-span-3,
  .bento-span-2 {
    grid-column: span 1;
  }
}

/* ============ 响应式：移动端 ============ */

@media (max-width: 768px) {
  :root {
    --header-h: 64px;
    --space-section: 56px;
  }

  .site-header__frame {
    height: var(--header-h);
    padding: 0 16px;
    gap: 12px;
  }

  .site-brand__text {
    font-size: 15px;
  }

  .site-brand__mark {
    width: 32px;
    height: 32px;
    font-size: 19px;
  }

  /* 移动端全屏菜单 */
  .nav-toggle {
    display: inline-flex;
    margin-left: auto;
  }

  .site-nav {
    position: fixed;
    inset: 0;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 32px;
    background:
      repeating-linear-gradient(-45deg, transparent 0, transparent 24px, rgba(212, 175, 55, 0.03) 24px, rgba(212, 175, 55, 0.03) 25px),
      rgba(11, 61, 46, 0.97);
    transform: translateX(100%);
    transition: transform 0.35s cubic-bezier(0.4, 0, 0.2, 1);
    z-index: 10;
    padding: 96px 32px 48px;
    overflow-y: auto;
  }

  .site-nav[data-open] {
    transform: translateX(0);
  }

  .site-nav__watermark {
    display: block;
    position: absolute;
    top: 64px;
    right: 24px;
    font-family: var(--font-headline);
    font-size: 64px;
    font-weight: 900;
    line-height: 1;
    color: rgba(212, 175, 55, 0.12);
    letter-spacing: 0.06em;
    pointer-events: none;
    text-transform: uppercase;
  }

  .site-nav__list {
    flex-direction: column;
    align-items: center;
    gap: 22px;
  }

  .site-nav__item::before {
    opacity: 0.5;
    font-size: 12px;
  }

  .site-nav__link {
    font-family: var(--font-headline);
    font-size: 24px;
    font-weight: 700;
    color: var(--color-bg);
    padding: 4px 8px;
    border-bottom: 1px solid transparent;
  }

  .site-nav__link:hover {
    color: var(--color-gold);
  }

  .site-nav__link[aria-current="page"] {
    color: var(--color-gold);
    border-bottom-color: var(--color-gold);
  }

  .site-header[data-scrolled="true"] .site-nav__link {
    color: var(--color-bg);
  }

  .site-header[data-scrolled="true"] .site-nav__link:hover {
    color: var(--color-gold);
  }

  .site-header[data-scrolled="true"] .site-nav__link[aria-current="page"] {
    color: var(--color-gold);
  }

  .site-nav__cta {
    width: min(280px, 100%);
    padding: 14px 24px;
    font-size: 16px;
    justify-content: center;
    background: var(--color-orange);
    color: #fff;
    border-color: var(--color-orange);
  }

  .site-nav__cta:hover {
    background: transparent;
    color: var(--color-orange);
  }

  .site-header[data-scrolled="true"] .site-nav__cta:hover {
    color: var(--color-gold);
    border-color: var(--color-gold);
  }

  /* 移动端页脚 */
  .site-footer {
    padding-top: 48px;
  }

  .site-footer__inner {
    grid-template-columns: 1fr;
    gap: 32px;
    padding: 0 16px 36px;
  }

  .site-footer__brand-col .site-footer__desc {
    max-width: 100%;
  }

  .site-footer__contact-inner {
    flex-direction: column;
    gap: 6px;
    text-align: center;
    padding: 16px;
  }

  .site-footer__sep {
    display: none;
  }

  .site-footer__bottom {
    padding: 20px 16px 24px;
  }

  .site-footer__trust {
    font-size: 11px;
  }

  /* 移动端网格 */
  .grid--2,
  .grid--3,
  .grid--4,
  .grid--bento {
    grid-template-columns: 1fr;
    grid-auto-rows: auto;
  }

  .bento-span-2,
  .bento-span-3 {
    grid-column: span 1;
  }

  .bento-row-2 {
    grid-row: span 1;
  }

  /* 移动端章节头 */
  .section__header {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
  }

  .section__num {
    font-size: 56px;
  }

  /* 移动端面包屑 */
  .breadcrumb {
    padding: 12px 16px;
    font-size: 12px;
  }

  /* 返回顶部 */
  .back-to-top {
    right: 16px;
    bottom: 16px;
    width: 40px;
    height: 40px;
  }
}

/* ============ 减少动态 ============ */

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

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }

  .site-nav {
    transition: none;
  }

  .back-to-top {
    transition: none;
  }
}