:root {
  --color-primary-bg: #0A0A0A;
  --color-primary-fg: #FFFFFF;
  --color-brand-accent: #D32F2F;
  --color-accent-secondary: #FFC107;
  --color-surface-light: #1E1E1E;
  --color-surface-dark: #121212;
  --color-neutral-gray: #B0B0B0;
  --color-border-subtle: #2C2C2C;
  --color-success-green: #4CAF50;
  --color-error-red: #E53935;
  --font-heading: 'Roboto Condensed', 'Impact', 'Arial Narrow', sans-serif;
  --font-body: 'Inter', -apple-system, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', 'Courier New', monospace;
  --size-h1: 3.5rem;
  --size-h2: 2.75rem;
  --size-h3: 2rem;
  --size-h4: 1.5rem;
  --size-body: 1rem;
  --size-small: 0.875rem;
  --size-data-value: 2.5rem;
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 2rem;
  --space-xl: 3rem;
  --space-2xl: 4rem;
  --max-width: 1280px;
  --header-upper-height: 3rem;
  --header-nav-height: 3.25rem;
  --header-total: calc(var(--header-upper-height) + var(--header-nav-height));
  --transition-fast: 150ms ease;
  --border-thin: 1px solid var(--color-border-subtle);
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-body);
  font-size: var(--size-body);
  line-height: 1.6;
  color: var(--color-primary-fg);
  background-color: var(--color-primary-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: 0.02em;
  color: var(--color-primary-fg);
}

h1 { font-size: var(--size-h1); }
h2 { font-size: var(--size-h2); }
h3 { font-size: var(--size-h3); }
h4 { font-size: var(--size-h4); }

p { margin-bottom: var(--space-md); }
a { color: var(--color-brand-accent); text-decoration: none; transition: color var(--transition-fast); }
a:hover { color: var(--color-accent-secondary); }
a:focus-visible { outline: 2px solid var(--color-accent-secondary); outline-offset: 2px; }
ul, ol { list-style: none; }
img { max-width: 100%; height: auto; display: block; }
small { font-size: var(--size-small); color: var(--color-neutral-gray); }

::selection { background: var(--color-brand-accent); color: var(--color-primary-fg); }

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

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

.skip-link {
  position: absolute;
  top: -100%;
  left: var(--space-md);
  z-index: 9999;
  padding: var(--space-sm) var(--space-md);
  background: var(--color-brand-accent);
  color: var(--color-primary-fg);
  font-family: var(--font-heading);
  font-size: var(--size-small);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  clip: rect(0 0 0 0);
  overflow: hidden;
  transition: top var(--transition-fast);
}

.skip-link:focus {
  top: var(--space-sm);
  clip: auto;
  overflow: visible;
}

/* ==================== SITE HEADER ==================== */
.site-header {
  position: relative;
  z-index: 1000;
  background: var(--color-primary-bg);
  border-bottom: 2px solid var(--color-brand-accent);
  box-shadow: 0 1px 0 var(--color-border-subtle), 0 4px 20px rgba(211, 47, 47, 0.08);
}

.site-header::before,
.site-header::after {
  content: '';
  position: absolute;
  bottom: -2px;
  width: 6px;
  height: 6px;
  background: var(--color-brand-accent);
  clip-path: polygon(0 0, 100% 0, 50% 100%);
  opacity: 0.6;
}

.site-header::before { left: var(--space-md); }
.site-header::after { right: var(--space-md); }

/* 滚动进度条 */
.scroll-progress {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--color-surface-dark);
  z-index: 1001;
  pointer-events: none;
}

.scroll-progress-bar {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, var(--color-brand-accent), var(--color-accent-secondary));
  transition: width 60ms linear;
  will-change: width;
}

/* 上层品牌区 */
.header-upper {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-upper-height);
  padding: 0 var(--space-lg);
  background: var(--color-surface-dark);
  border-bottom: var(--border-thin);
}

.brand {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.brand-logo {
  font-size: 1.35rem;
  line-height: 1;
  filter: drop-shadow(0 0 4px rgba(211, 47, 47, 0.3));
}

.brand-name {
  font-family: var(--font-heading);
  font-size: 1.15rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-brand-accent);
}

.header-tagline {
  font-family: var(--font-mono);
  font-size: var(--size-small);
  color: var(--color-neutral-gray);
  letter-spacing: 0.04em;
  white-space: nowrap;
}

.header-tagline::before {
  content: '// ';
  color: var(--color-accent-secondary);
  font-weight: 700;
}

/* 下层导航 */
.header-nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-nav-height);
  padding: 0 var(--space-lg);
  background: var(--color-primary-bg);
  position: relative;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 2.5rem;
  height: 2.5rem;
  background: transparent;
  border: 1px solid var(--color-border-subtle);
  border-radius: 4px;
  cursor: pointer;
  gap: 5px;
  padding: 6px;
  transition: border-color var(--transition-fast);
}

.nav-toggle:hover { border-color: var(--color-brand-accent); }
.nav-toggle:focus-visible { outline: 2px solid var(--color-accent-secondary); outline-offset: 2px; }

.nav-toggle-line {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--color-primary-fg);
  transition: transform var(--transition-fast), opacity var(--transition-fast);
  transform-origin: center;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 0;
  width: 100%;
}

.nav-list li {
  flex: 1;
  display: flex;
  align-items: center;
}

.nav-list li + li::before {
  content: '|';
  color: var(--color-border-subtle);
  font-size: var(--size-small);
  font-weight: 300;
  margin-right: 0;
}

.nav-list a {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  padding: var(--space-sm) var(--space-xs);
  font-family: var(--font-heading);
  font-size: var(--size-small);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-primary-fg);
  white-space: nowrap;
  position: relative;
  transition: color var(--transition-fast), background var(--transition-fast);
}

.nav-list a::after {
  content: '';
  position: absolute;
  bottom: 4px;
  left: 20%;
  right: 20%;
  height: 2px;
  background: var(--color-brand-accent);
  transform: scaleX(0);
  transition: transform var(--transition-fast), background var(--transition-fast);
}

.nav-list a:hover {
  color: var(--color-accent-secondary);
}

.nav-list a:hover::after {
  transform: scaleX(1);
  background: var(--color-accent-secondary);
}

.nav-list a[aria-current="page"] {
  color: var(--color-primary-fg);
  background: rgba(211, 47, 47, 0.18);
  border-radius: 2px;
}

.nav-list a[aria-current="page"]::after {
  transform: scaleX(1);
  background: var(--color-brand-accent);
}

/* ==================== SITE FOOTER ==================== */
.site-footer {
  background: var(--color-primary-bg);
  border-top: 2px solid var(--color-brand-accent);
  padding: var(--space-xl) var(--space-lg) var(--space-md);
  margin-top: var(--space-2xl);
  position: relative;
}

.site-footer::before,
.site-footer::after {
  content: '';
  position: absolute;
  top: -2px;
  width: 6px;
  height: 6px;
  background: var(--color-brand-accent);
  clip-path: polygon(50% 0%, 0% 100%, 100% 100%);
  opacity: 0.6;
}

.site-footer::before { left: var(--space-md); }
.site-footer::after { right: var(--space-md); }

.footer-inner {
  display: grid;
  grid-template-columns: 2fr 1fr 1.5fr;
  gap: var(--space-xl);
  max-width: var(--max-width);
  margin: 0 auto;
  padding-bottom: var(--space-lg);
  border-bottom: var(--border-thin);
}

.footer-brand .brand-logo {
  font-size: 1.6rem;
  display: inline-block;
  margin-bottom: var(--space-xs);
}

.footer-brand .brand-name {
  font-size: 1.4rem;
  display: inline-block;
  vertical-align: middle;
  margin-left: var(--space-xs);
}

.footer-tagline {
  font-family: var(--font-mono);
  font-size: var(--size-small);
  color: var(--color-accent-secondary);
  margin-top: var(--space-sm);
  margin-bottom: var(--space-xs);
  letter-spacing: 0.04em;
}

.footer-desc {
  font-size: var(--size-small);
  color: var(--color-neutral-gray);
  line-height: 1.7;
  max-width: 30em;
  margin-top: var(--space-sm);
}

.footer-nav {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
  padding-top: var(--space-xs);
}

.footer-nav a {
  font-family: var(--font-heading);
  font-size: var(--size-body);
  font-weight: 600;
  color: var(--color-primary-fg);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  position: relative;
  padding-left: var(--space-md);
  transition: color var(--transition-fast);
}

.footer-nav a::before {
  content: '›';
  position: absolute;
  left: 0;
  color: var(--color-brand-accent);
  font-weight: 700;
  font-size: 1.2rem;
}

.footer-nav a:hover {
  color: var(--color-accent-secondary);
}

.footer-contact {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  padding-top: var(--space-xs);
}

.footer-contact-label {
  font-family: var(--font-heading);
  font-size: var(--size-small);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-brand-accent);
  margin-bottom: var(--space-xs);
}

.footer-contact a,
.footer-contact span {
  font-size: var(--size-small);
  color: var(--color-neutral-gray);
  transition: color var(--transition-fast);
}

.footer-contact a:hover {
  color: var(--color-accent-secondary);
}

.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-sm);
  max-width: var(--max-width);
  margin: var(--space-md) auto 0;
  font-size: var(--size-small);
  color: var(--color-neutral-gray);
}

.footer-contact-note {
  color: var(--color-neutral-gray);
  font-size: var(--size-small);
  opacity: 0.7;
}

/* ==================== 通用容器 ==================== */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

/* ==================== 通用按钮 ==================== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-lg);
  font-family: var(--font-heading);
  font-size: var(--size-small);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-primary-fg);
  background: var(--color-brand-accent);
  border: 1px solid var(--color-brand-accent);
  border-radius: 0;
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none;
  line-height: 1.4;
}

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

.btn:focus-visible {
  outline: 2px solid var(--color-accent-secondary);
  outline-offset: 2px;
}

.btn--outline {
  background: transparent;
  color: var(--color-primary-fg);
  border-color: var(--color-border-subtle);
}

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

/* ==================== 面包屑 ==================== */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-md) 0;
  font-family: var(--font-mono);
  font-size: var(--size-small);
  color: var(--color-neutral-gray);
  border-bottom: var(--border-thin);
  margin-bottom: var(--space-lg);
}

.breadcrumb a {
  color: var(--color-brand-accent);
  text-decoration: none;
  transition: color var(--transition-fast);
}

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

.breadcrumb span {
  color: var(--color-neutral-gray);
}

.breadcrumb li + li::before {
  content: '/';
  color: var(--color-border-subtle);
  margin-right: var(--space-sm);
}

/* ==================== 网格基础 ==================== */
.grid {
  display: grid;
  gap: var(--space-lg);
}

.grid--2 { grid-template-columns: repeat(2, 1fr); }
.grid--3 { grid-template-columns: repeat(3, 1fr); }
.grid--4 { grid-template-columns: repeat(4, 1fr); }

/* ==================== 图片容器基础 ==================== */
.figure {
  position: relative;
  overflow: hidden;
  background: var(--color-surface-dark);
  border: var(--border-thin);
  aspect-ratio: 16 / 9;
  display: flex;
  align-items: center;
  justify-content: center;
}

.figure img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--transition-fast);
}

.figure:hover img {
  transform: scale(1.02);
}

.figure-placeholder {
  color: var(--color-neutral-gray);
  font-family: var(--font-mono);
  font-size: var(--size-small);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  opacity: 0.5;
}

/* ==================== 响应式 ==================== */
@media (max-width: 1024px) {
  .footer-inner {
    grid-template-columns: 1fr 1fr;
    gap: var(--space-lg);
  }
  .footer-contact { grid-column: 1 / -1; }
}

@media (max-width: 768px) {
  :root {
    --header-upper-height: 2.75rem;
    --header-nav-height: 3rem;
    --size-h1: 2.25rem;
    --size-h2: 1.9rem;
    --size-h3: 1.5rem;
    --size-h4: 1.2rem;
  }

  .header-upper {
    padding: 0 var(--space-md);
  }

  .header-tagline {
    font-size: 0.7rem;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    max-width: 50%;
  }

  .header-tagline::before { content: ''; }

  .header-nav {
    padding: 0 var(--space-md);
    position: relative;
  }

  .nav-toggle {
    display: flex;
  }

  .nav-list {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    background: var(--color-surface-dark);
    border-bottom: 2px solid var(--color-brand-accent);
    box-shadow: 0 8px 32px rgba(0,0,0,0.6);
    padding: var(--space-sm) 0;
    gap: 0;
    transform: scaleY(0);
    transform-origin: top center;
    opacity: 0;
    visibility: hidden;
    transition: transform 200ms ease, opacity 200ms ease, visibility 200ms ease;
    pointer-events: none;
  }

  .header-nav[data-open] .nav-list {
    transform: scaleY(1);
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
  }

  .nav-list li {
    width: 100%;
    flex: 0 0 auto;
  }

  .nav-list li + li::before { content: none; }

  .nav-list a {
    padding: var(--space-md);
    font-size: var(--size-body);
    justify-content: flex-start;
    border-bottom: var(--border-thin);
  }

  .nav-list a::after { display: none; }

  .nav-list a[aria-current="page"] {
    background: rgba(211, 47, 47, 0.25);
    border-left: 3px solid var(--color-brand-accent);
  }

  /* 汉堡动画 */
  [data-nav-toggle][aria-expanded="true"] .nav-toggle-line:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
  }
  [data-nav-toggle][aria-expanded="true"] .nav-toggle-line:nth-child(2) {
    opacity: 0;
  }
  [data-nav-toggle][aria-expanded="true"] .nav-toggle-line:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
  }

  .site-footer {
    padding: var(--space-lg) var(--space-md) var(--space-md);
  }

  .footer-inner {
    grid-template-columns: 1fr;
    gap: var(--space-lg);
  }

  .footer-bottom {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--space-xs);
  }

  .container {
    padding: 0 var(--space-md);
  }

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

@media (max-width: 480px) {
  .header-tagline { display: none; }
  .brand-name { font-size: 1rem; }
  .nav-list a { font-size: var(--size-small); }
}