:root {
  --deep-blue: #0A192F;
  --ink-blue: #1B263B;
  --warm-paper: #F5F1E8;
  --orange-accent: #FCA311;
  --gold-accent: #E8A33D;
  --text-primary: #0D1B2A;
  --text-secondary: #E0E1DD;
  --gray-line: #778DA9;
  --success: #2A9D8F;
  --danger: #E76F51;
  --header-width: 280px;
  --content-max: 1440px;
  --font-heading: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  --font-body: "Source Han Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --transition-base: 200ms ease;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.6;
  color: var(--text-secondary);
  background-color: var(--deep-blue);
  padding-left: var(--header-width);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

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

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

ul, ol {
  list-style: none;
}

button {
  font-family: inherit;
  background: none;
  border: none;
  cursor: pointer;
  color: inherit;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 700;
  line-height: 1.3;
  color: var(--deep-blue);
}

h1 {
  font-size: 48px;
}

h2 {
  font-size: 36px;
}

h3 {
  font-size: 24px;
}

p {
  line-height: 1.6;
}

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

.skip-link {
  position: fixed;
  top: -120px;
  left: 50%;
  transform: translateX(-50%);
  background-color: var(--orange-accent);
  color: var(--deep-blue);
  padding: 0.625rem 1.25rem;
  border-radius: 0 0 10px 10px;
  font-family: var(--font-heading);
  font-size: 14px;
  font-weight: 600;
  text-decoration: none;
  z-index: 9999;
  transition: top 200ms ease;
  box-shadow: 0 4px 16px rgba(252, 163, 17, 0.35);
}

.skip-link:focus {
  top: 0;
}

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  width: var(--header-width);
  background-color: var(--deep-blue);
  color: var(--text-secondary);
  border-right: 1px solid rgba(232, 163, 61, 0.25);
  z-index: 1000;
}

.header-inner {
  display: flex;
  flex-direction: column;
  height: 100%;
  padding: 2.5rem 1.75rem 1.5rem;
  gap: 2.5rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
}

.brand-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  background: linear-gradient(135deg, var(--orange-accent) 0%, var(--gold-accent) 100%);
  color: var(--deep-blue);
  font-size: 16px;
  font-weight: 700;
  clip-path: polygon(50% 0, 100% 50%, 50% 100%, 0 50%);
  flex-shrink: 0;
}

.brand-name {
  font-family: var(--font-heading);
  font-size: 22px;
  font-weight: 700;
  color: var(--warm-paper);
  letter-spacing: 0.12em;
  line-height: 1.2;
  white-space: nowrap;
}

.site-nav {
  display: flex;
  flex-direction: column;
  flex: 1;
}

.nav-list {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.nav-item {
  position: relative;
}

.nav-link {
  display: block;
  padding: 0.7rem 1rem;
  color: var(--gray-line);
  text-decoration: none;
  font-family: var(--font-heading);
  font-size: 15px;
  font-weight: 500;
  letter-spacing: 0.06em;
  border-left: 2px solid transparent;
  border-radius: 0 6px 6px 0;
  transition: color 200ms ease, border-color 200ms ease, background-color 200ms ease;
}

.nav-link:hover {
  color: var(--warm-paper);
  border-left-color: var(--gold-accent);
  background: linear-gradient(90deg, rgba(232, 163, 61, 0.08), transparent);
}

.nav-link[aria-current="page"] {
  color: var(--warm-paper);
  border-left-color: var(--orange-accent);
  font-weight: 600;
  background: linear-gradient(90deg, rgba(252, 163, 17, 0.1), transparent);
}

.nav-link[aria-current="page"]::after {
  content: "";
  position: absolute;
  right: 12px;
  top: 50%;
  transform: translateY(-50%);
  width: 6px;
  height: 6px;
  background: var(--orange-accent);
  border-radius: 50%;
}

.nav-cta {
  margin-top: auto;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  padding-top: 2rem;
}

.nav-note {
  font-size: 12px;
  color: var(--gray-line);
  text-align: center;
  letter-spacing: 0.08em;
  line-height: 1.5;
}

.nav-toggle {
  display: none;
}

.site-footer {
  background-color: var(--deep-blue);
  color: var(--text-secondary);
  border-top: 2px solid rgba(232, 163, 61, 0.25);
}

.footer-inner {
  max-width: var(--content-max);
  margin: 0 auto;
  padding: 3.5rem 2rem;
  display: grid;
  grid-template-columns: 2fr 1fr 1.5fr;
  gap: 2.5rem;
}

.footer-brand .brand {
  margin-bottom: 1rem;
}

.footer-tagline {
  font-size: 14px;
  color: var(--gray-line);
  line-height: 1.7;
  max-width: 320px;
}

.footer-title {
  font-family: var(--font-heading);
  font-size: 16px;
  font-weight: 600;
  color: var(--warm-paper);
  margin-bottom: 1rem;
  letter-spacing: 0.06em;
}

.footer-link-list,
.footer-contact-list {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.footer-link-list a {
  color: var(--gray-line);
  text-decoration: none;
  font-size: 14px;
  transition: color 200ms ease;
}

.footer-link-list a:hover {
  color: var(--orange-accent);
}

.footer-contact-list li {
  font-size: 14px;
  color: var(--gray-line);
  line-height: 1.5;
}

.footer-bottom {
  border-top: 1px solid rgba(119, 141, 169, 0.2);
  padding: 1.25rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  font-size: 13px;
  color: var(--gray-line);
  max-width: var(--content-max);
  margin: 0 auto;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.7rem 1.25rem;
  border-radius: 6px;
  font-family: var(--font-heading);
  font-size: 14px;
  font-weight: 600;
  text-decoration: none;
  border: none;
  cursor: pointer;
  transition: background-color 200ms ease, color 200ms ease, box-shadow 200ms ease, transform 200ms ease;
}

.btn-primary {
  background-color: var(--orange-accent);
  color: var(--deep-blue);
  box-shadow: 0 2px 8px rgba(252, 163, 17, 0.3);
}

.btn-primary:hover {
  background-color: #ffb737;
  box-shadow: 0 4px 16px rgba(252, 163, 17, 0.4);
  transform: translateY(-1px);
}

.btn-ghost {
  background: transparent;
  border: 1px solid rgba(232, 163, 61, 0.4);
  color: var(--text-secondary);
}

.btn-ghost:hover {
  border-color: var(--gold-accent);
  color: var(--gold-accent);
  background: rgba(232, 163, 61, 0.05);
}

.main-content {
  background-color: var(--warm-paper);
  color: var(--text-primary);
  min-height: 60vh;
}

#main-content:focus {
  outline: none;
}

.content-container {
  max-width: var(--content-max);
  margin: 0 auto;
  padding: 0 2rem;
}

.section {
  padding: 4rem 0;
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem;
  font-size: 13px;
  color: var(--gray-line);
  padding: 1.5rem 0 0;
}

.breadcrumb a {
  color: var(--gray-line);
  text-decoration: none;
  transition: color 200ms ease;
}

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

.card {
  background-color: var(--warm-paper);
  border-radius: 12px;
  padding: 1.5rem;
  box-shadow: 0 2px 12px rgba(10, 25, 47, 0.06);
  transition: transform 200ms ease, box-shadow 200ms ease;
}

.card:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 24px rgba(10, 25, 47, 0.12);
}

.card--dark {
  background-color: var(--ink-blue);
  color: var(--text-secondary);
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.2);
}

.card--dark h1,
.card--dark h2,
.card--dark h3 {
  color: var(--warm-paper);
}

.figure-block {
  position: relative;
  overflow: hidden;
  border-radius: 12px;
  background-color: var(--ink-blue);
  min-height: 200px;
}

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

.figure-block::after {
  content: attr(data-caption);
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  padding: 0.5rem 0.75rem;
  background: rgba(10, 25, 47, 0.6);
  color: var(--warm-paper);
  font-size: 12px;
  backdrop-filter: blur(4px);
  opacity: 0;
  transition: opacity 200ms ease;
}

.figure-block:hover::after {
  opacity: 1;
}

.grid {
  display: grid;
  gap: 1.5rem;
}

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

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

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

.prose p + p {
  margin-top: 1em;
}

.prose a {
  color: var(--orange-accent);
  text-decoration: underline;
  text-underline-offset: 4px;
  transition: color 200ms ease;
}

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

.geo-diamond {
  display: inline-block;
  width: 8px;
  height: 8px;
  background: var(--gold-accent);
  transform: rotate(45deg);
  flex-shrink: 0;
}

.orbit-line {
  pointer-events: none;
  border: 1px solid rgba(232, 163, 61, 0.15);
  border-radius: 50%;
}

.back-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background-color: var(--orange-accent);
  color: var(--deep-blue);
  font-size: 18px;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 16px rgba(252, 163, 17, 0.4);
  opacity: 0;
  visibility: hidden;
  transform: translateY(12px);
  transition: opacity 200ms ease, transform 200ms ease, visibility 200ms ease;
  z-index: 98;
}

.back-top:hover {
  background-color: #ffb737;
  transform: translateY(-2px);
}

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

@media (max-width: 1200px) {
  body {
    padding-left: 0;
  }

  .site-header {
    position: sticky;
    top: 0;
    width: 100%;
    height: auto;
    border-right: none;
    border-bottom: 1px solid rgba(232, 163, 61, 0.25);
    z-index: 1000;
  }

  .header-inner {
    flex-direction: row;
    align-items: center;
    height: auto;
    padding: 0.6rem 1rem;
    gap: 0.75rem;
    min-height: 64px;
  }

  .brand-mark {
    width: 32px;
    height: 32px;
    font-size: 13px;
  }

  .brand-name {
    font-size: 18px;
  }

  .site-nav {
    position: fixed;
    top: 64px;
    left: 0;
    bottom: 0;
    width: min(320px, 85vw);
    background-color: var(--ink-blue);
    z-index: 999;
    padding: 2rem 1.5rem;
    transform: translateX(-110%);
    transition: transform 300ms ease, box-shadow 300ms ease;
    box-shadow: none;
    overflow-y: auto;
    flex: none;
  }

  .site-nav[data-open] {
    transform: translateX(0);
    box-shadow: 8px 0 32px rgba(0, 0, 0, 0.4);
  }

  .nav-list {
    gap: 0.125rem;
  }

  .nav-link {
    font-size: 17px;
    padding: 0.85rem 1.25rem;
  }

  .nav-link[aria-current="page"]::after {
    right: 16px;
  }

  .nav-cta {
    margin-top: auto;
    padding-top: 1.5rem;
  }

  .nav-toggle {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 5px;
    width: 44px;
    height: 44px;
    background: transparent;
    border: 1px solid rgba(232, 163, 61, 0.4);
    border-radius: 8px;
    cursor: pointer;
    padding: 8px;
    margin-left: auto;
    flex-shrink: 0;
  }

  .nav-toggle-bar {
    display: block;
    width: 20px;
    height: 2px;
    background-color: var(--warm-paper);
    border-radius: 2px;
    transition: transform 200ms ease, opacity 200ms ease;
  }

  .nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(1) {
    transform: translateY(7px) 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(-7px) rotate(-45deg);
  }

  .footer-inner {
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
  }

  .footer-brand {
    grid-column: 1 / -1;
  }
}

@media (max-width: 768px) {
  .footer-inner {
    grid-template-columns: 1fr;
    padding: 2.5rem 1.5rem;
    gap: 2rem;
  }

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

  .footer-bottom {
    flex-direction: column;
    text-align: center;
    padding: 1.25rem 1rem;
    gap: 0.25rem;
  }

  .grid--2cols,
  .grid--3cols,
  .grid--4cols {
    grid-template-columns: 1fr;
  }

  h1 {
    font-size: 36px;
  }

  h2 {
    font-size: 28px;
  }

  h3 {
    font-size: 20px;
  }
}

@media (min-width: 769px) and (max-width: 1200px) {
  .grid--4cols {
    grid-template-columns: repeat(2, 1fr);
  }
}

@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;
  }

  .site-nav {
    transition: none !important;
  }

  .back-top {
    transition: none !important;
  }
}