:root {
  --color-primary: #0A1E3D;
  --color-primary-deep: #071529;
  --color-primary-card: #132B52;
  --color-gold: #D4A843;
  --color-gold-light: #F2E6C9;
  --color-orange: #FF6B2C;
  --color-text: #F5F7FA;
  --color-muted: #A0B0C8;
  --color-line: #8C6E2F;
  --font-head: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-body: "Noto Serif SC", "Source Han Serif SC", "Songti SC", serif;
  --font-mono: "JetBrains Mono", "SF Mono", "Courier New", monospace;
  --header-width: 220px;
  --container-max: 1200px;
  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
  --header-z: 1000;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  background: var(--color-primary);
  color: var(--color-text);
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.75;
  padding-left: var(--header-width);
  -webkit-font-smoothing: antialiased;
}

.site-main {
  display: block;
  min-height: 70vh;
}

a {
  color: inherit;
}

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

button {
  font: inherit;
}

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

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: fixed;
  top: 12px;
  left: calc(var(--header-width) + 12px);
  z-index: 3000;
  padding: 8px 14px;
  background: var(--color-gold);
  color: var(--color-primary);
  font-family: var(--font-head);
  font-size: 0.8rem;
  text-decoration: none;
  border-radius: 2px;
  transform: translateY(-200%);
  transition: transform 0.2s ease;
}

.skip-link:focus {
  transform: translateY(0);
}

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

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--header-width);
  height: 100vh;
  display: flex;
  z-index: var(--header-z);
  background: transparent;
  border-right: 1px solid rgba(212, 168, 67, 0.18);
  transition: background 0.3s var(--ease), box-shadow 0.3s var(--ease);
}

.site-header.is-scrolled {
  background: rgba(10, 30, 61, 0.96);
  box-shadow: 8px 0 32px rgba(7, 21, 41, 0.25);
}

.site-header__inner {
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  padding: 26px 22px 22px;
}

.site-header__top {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 16px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: var(--color-text);
}

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

.brand__mark {
  width: 42px;
  height: 42px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex: none;
  border: 1px solid var(--color-gold);
  background: linear-gradient(135deg, var(--color-gold), var(--color-gold-light));
  color: var(--color-primary);
  font-family: var(--font-head);
  font-weight: 800;
  font-size: 20px;
  border-radius: 2px;
  box-shadow: 0 0 0 3px rgba(212, 168, 67, 0.15);
}

.brand__text {
  display: grid;
  gap: 2px;
}

.brand__title {
  font-family: var(--font-head);
  font-size: 1rem;
  letter-spacing: 0.16em;
  transition: color 0.2s;
}

.brand__subtitle {
  font-family: var(--font-mono);
  font-size: 0.58rem;
  letter-spacing: 0.22em;
  color: var(--color-gold);
}

.site-header__badge {
  margin: 24px 0 16px;
}

.status-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 5px 10px;
  border: 1px solid rgba(212, 168, 67, 0.3);
  border-radius: 999px;
  background: rgba(212, 168, 67, 0.06);
  font-family: var(--font-head);
  font-size: 0.72rem;
  color: var(--color-gold-light);
  letter-spacing: 0.04em;
}

.status-badge__dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--color-orange);
  animation: statusPulse 2s infinite;
}

@keyframes statusPulse {
  0% {
    box-shadow: 0 0 0 0 rgba(255, 107, 44, 0.55);
  }
  70% {
    box-shadow: 0 0 0 8px rgba(255, 107, 44, 0);
  }
  100% {
    box-shadow: 0 0 0 0 rgba(255, 107, 44, 0);
  }
}

.site-nav {
  flex: 1;
  display: flex;
  flex-direction: column;
  justify-content: center;
  margin: 0;
}

.nav-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 8px;
}

.nav-list__item {
  margin: 0;
}

.nav-link {
  position: relative;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 0;
  color: var(--color-text);
  text-decoration: none;
  font-family: var(--font-head);
  font-size: 0.92rem;
  line-height: 1;
  letter-spacing: 0.06em;
  border-bottom: 1px solid rgba(212, 168, 67, 0.12);
  transition: color 0.2s, padding-left 0.25s var(--ease);
}

.nav-link__index {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  color: var(--color-gold);
  opacity: 0.85;
  letter-spacing: 0.05em;
}

.nav-link__text {
  font-weight: 500;
}

.nav-link::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -1px;
  width: 0;
  height: 2px;
  background: var(--color-orange);
  transition: width 0.25s var(--ease);
}

.nav-link:hover,
.nav-link:focus-visible {
  color: var(--color-gold-light);
  padding-left: 4px;
  background: transparent;
}

.nav-link:hover::after,
.nav-link:focus-visible::after {
  width: 100%;
}

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

.nav-link[aria-current="page"]::after {
  width: 100%;
  background: var(--color-gold);
}

.site-header__contact {
  margin-top: auto;
  border-top: 1px solid rgba(212, 168, 67, 0.14);
  padding-top: 16px;
  display: grid;
  gap: 4px;
}

.header-contact__label {
  font-family: var(--font-head);
  font-size: 0.68rem;
  letter-spacing: 0.18em;
  color: var(--color-muted);
  text-transform: uppercase;
}

.header-contact__value {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--color-gold-light);
  line-height: 1.5;
}

.header-contact__link {
  display: inline-block;
  margin-top: 8px;
  font-family: var(--font-head);
  font-size: 0.78rem;
  color: var(--color-gold);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.2s;
  width: fit-content;
}

.header-contact__link:hover,
.header-contact__link:focus-visible {
  border-bottom-color: var(--color-gold);
}

.mobile-nav-toggle {
  display: none;
}

.site-footer {
  position: relative;
  background: linear-gradient(180deg, var(--color-primary), var(--color-primary-deep) 140%);
  border-top: 1px solid rgba(212, 168, 67, 0.2);
  overflow: hidden;
}

.site-footer::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--color-gold) 0 60%, var(--color-orange) 100%);
  opacity: 0.85;
}

.site-footer__inner {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 64px 40px 32px;
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1.2fr;
  gap: 48px;
}

.site-footer__brand {
  display: grid;
  gap: 18px;
  align-content: start;
}

.brand--footer {
  flex-wrap: nowrap;
}

.site-footer__statement {
  margin: 0;
  color: var(--color-muted);
  font-size: 0.86rem;
  line-height: 1.8;
  max-width: 32ch;
}

.site-footer__col,
.site-footer__col--contact {
  display: grid;
  gap: 14px;
  align-content: start;
}

.site-footer__heading {
  margin: 0;
  font-family: var(--font-head);
  font-size: 0.78rem;
  letter-spacing: 0.2em;
  color: var(--color-gold);
  text-transform: uppercase;
  border-bottom: 1px solid rgba(212, 168, 67, 0.16);
  padding-bottom: 8px;
}

.site-footer__links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 8px;
}

.site-footer__links a {
  color: var(--color-text);
  text-decoration: none;
  font-size: 0.86rem;
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  transition: color 0.2s;
  border-bottom: 1px solid transparent;
}

.site-footer__links a::before {
  content: "·";
  color: var(--color-orange);
  font-family: var(--font-mono);
}

.site-footer__links a:hover,
.site-footer__links a:focus-visible {
  color: var(--color-gold);
  border-bottom-color: rgba(212, 168, 67, 0.4);
}

.site-footer__contact {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.site-footer__contact li {
  display: grid;
  gap: 2px;
  font-size: 0.84rem;
  line-height: 1.5;
}

.footer-contact__label {
  font-family: var(--font-head);
  font-size: 0.68rem;
  letter-spacing: 0.14em;
  color: var(--color-gold);
  text-transform: uppercase;
}

.site-footer__contact li span:last-child {
  color: var(--color-text);
}

.site-footer__meta {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 18px 40px 28px;
  border-top: 1px solid rgba(212, 168, 67, 0.12);
  display: flex;
  flex-wrap: wrap;
  gap: 12px 28px;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--color-muted);
}

.back-top {
  position: fixed;
  bottom: 26px;
  right: 26px;
  width: 44px;
  height: 44px;
  border: 1px solid var(--color-gold);
  border-radius: 50%;
  background: rgba(10, 30, 61, 0.92);
  color: var(--color-gold);
  font-size: 1.1rem;
  cursor: pointer;
  z-index: 1200;
  opacity: 0;
  transform: translateY(14px) scale(0.92);
  pointer-events: none;
  transition: opacity 0.25s var(--ease), transform 0.25s var(--ease), background 0.2s, color 0.2s;
}

.back-top.is-visible {
  opacity: 1;
  transform: translateY(0) scale(1);
  pointer-events: auto;
}

.back-top:hover,
.back-top:focus-visible {
  background: var(--color-gold);
  color: var(--color-primary);
}

.content-container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 56px clamp(20px, 4vw, 48px);
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  list-style: none;
  margin: 0 0 32px;
  padding: 0;
  font-family: var(--font-mono);
  font-size: 0.76rem;
  color: var(--color-muted);
}

.breadcrumb li {
  display: flex;
  align-items: center;
  gap: 6px;
}

.breadcrumb li + li::before {
  content: "/";
  color: var(--color-line);
}

.breadcrumb a {
  color: var(--color-gold);
  text-decoration: none;
  border-bottom: 1px solid transparent;
}

.breadcrumb a:hover {
  color: var(--color-orange);
  border-bottom-color: var(--color-orange);
}

.section-header {
  margin-bottom: 36px;
}

.section-index {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.24em;
  color: var(--color-gold);
  text-transform: uppercase;
}

.section-title {
  font-family: var(--font-head);
  font-size: clamp(1.9rem, 4vw, 3.2rem);
  line-height: 1.15;
  margin: 10px 0 14px;
  color: var(--color-text);
  letter-spacing: 0.02em;
}

.section-subtitle {
  color: var(--color-muted);
  font-size: 0.98rem;
  max-width: 70ch;
  margin: 0;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 44px;
  padding: 10px 22px;
  border: 1px solid transparent;
  border-radius: 2px;
  font-family: var(--font-head);
  font-size: 0.88rem;
  letter-spacing: 0.05em;
  text-decoration: none;
  cursor: pointer;
  transition: background 0.2s, color 0.2s, border-color 0.2s;
  white-space: nowrap;
}

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

.btn--primary:hover,
.btn--primary:focus-visible {
  background: var(--color-gold-light);
  border-color: var(--color-gold-light);
}

.btn--ghost {
  background: transparent;
  color: var(--color-gold);
  border-color: rgba(212, 168, 67, 0.55);
}

.btn--ghost:hover,
.btn--ghost:focus-visible {
  background: var(--color-gold);
  color: var(--color-primary);
}

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

.btn--orange:hover,
.btn--orange:focus-visible {
  background: #e05317;
  border-color: #e05317;
  color: #fff;
}

.paper-card {
  position: relative;
  background: linear-gradient(145deg, rgba(19, 43, 82, 0.82), rgba(19, 43, 82, 0.4));
  border: 1px solid rgba(212, 168, 67, 0.18);
  border-radius: 4px;
  padding: 24px;
}

.paper-card::before {
  content: "";
  position: absolute;
  inset: 8px;
  border: 1px solid rgba(212, 168, 67, 0.08);
  border-radius: 2px;
  pointer-events: none;
}

.paper-card > * {
  position: relative;
}

.image-frame,
.image-frame--16x9 {
  position: relative;
  overflow: hidden;
  background: var(--color-primary-card);
  border: 1px solid rgba(212, 168, 67, 0.2);
  aspect-ratio: 16 / 9;
}

.image-frame::after {
  content: "IMG";
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-mono);
  font-size: 0.76rem;
  letter-spacing: 0.34em;
  color: var(--color-gold);
  opacity: 0.55;
}

.image-frame > img,
.image-frame > picture {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.image-frame--4x5 {
  aspect-ratio: 4 / 5;
}

.image-frame--1x1 {
  aspect-ratio: 1 / 1;
}

.image-frame--wide {
  aspect-ratio: 21 / 9;
}

@media (max-width: 1024px) {
  .site-footer__inner {
    grid-template-columns: 1fr 1fr;
    gap: 40px;
  }
}

@media (max-width: 960px) {
  body {
    padding-left: 0;
    padding-top: 64px;
  }

  .site-header {
    width: 100%;
    height: auto;
    border-right: 0;
    border-bottom: 1px solid rgba(212, 168, 67, 0.2);
    background: rgba(10, 30, 61, 0.97);
  }

  .site-header.is-scrolled {
    background: rgba(10, 30, 61, 0.99);
    box-shadow: 0 8px 24px rgba(7, 21, 41, 0.2);
  }

  .site-header__inner {
    position: relative;
    height: auto;
    padding: 12px 16px;
    display: flex;
    flex-direction: column;
  }

  .site-header__top {
    width: 100%;
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
  }

  .brand__mark {
    width: 38px;
    height: 38px;
    font-size: 18px;
  }

  .brand__subtitle {
    font-size: 0.52rem;
  }

  .mobile-nav-toggle {
    display: inline-flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 5px;
    width: 44px;
    height: 44px;
    background: transparent;
    border: 1px solid rgba(212, 168, 67, 0.35);
    border-radius: 4px;
    cursor: pointer;
    padding: 0;
  }

  .mobile-nav-toggle__line {
    width: 18px;
    height: 2px;
    background: var(--color-gold);
    display: block;
    transition: transform 0.25s var(--ease), opacity 0.2s var(--ease);
  }

  button[aria-expanded="true"] .mobile-nav-toggle__line:nth-of-type(1) {
    transform: translateY(7px) rotate(45deg);
  }

  button[aria-expanded="true"] .mobile-nav-toggle__line:nth-of-type(2) {
    opacity: 0;
  }

  button[aria-expanded="true"] .mobile-nav-toggle__line:nth-of-type(3) {
    transform: translateY(-7px) rotate(-45deg);
  }

  .site-header__badge {
    display: none;
  }

  .site-header__contact {
    display: none;
  }

  .site-nav {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: rgba(10, 30, 61, 0.99);
    border-bottom: 1px solid rgba(212, 168, 67, 0.2);
    padding: 14px 16px 18px;
    box-shadow: 0 18px 30px rgba(7, 21, 41, 0.28);
    flex-direction: column;
  }

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

  .nav-list {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 6px 16px;
  }

  .nav-link {
    padding: 9px 0;
    font-size: 0.9rem;
  }

  .read-progress {
    left: 0;
  }

  .skip-link {
    left: 12px;
  }

  .site-footer__inner {
    grid-template-columns: 1fr 1fr;
    padding: 48px 24px 28px;
  }

  .site-footer__meta {
    padding: 16px 24px 24px;
  }

  .back-top {
    bottom: 18px;
    right: 18px;
  }
}

@media (max-width: 600px) {
  .site-footer__inner {
    grid-template-columns: 1fr;
    gap: 32px;
  }

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

  .site-footer__meta {
    flex-direction: column;
    gap: 8px;
  }

  .content-container {
    padding: 36px 18px;
  }
}

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

  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}