/* === RESET === */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body { min-height: 100vh; line-height: 1.6; overflow-x: hidden; }
ul, ol { list-style: none; }
a { text-decoration: none; color: inherit; }
img, svg { display: block; max-width: 100%; }
button { font: inherit; border: none; background: none; cursor: pointer; color: inherit; }
input, textarea, select { font: inherit; color: inherit; }
h1, h2, h3, h4, h5, h6 { font-weight: 900; line-height: 1.2; }
:focus-visible { outline: 2px solid #00D4FF; outline-offset: 2px; }

/* === VARIABLES === */
:root {
  /* 色彩 — 暗黑背景 + 奶油底对比 */
  --color-bg: #0D0D0D;
  --color-surface: #FFF8E7;
  --color-surface-alt: #F5F0E8;
  --color-text-light: #F5F0E8;
  --color-text-dark: #2C1E16;
  --color-text-muted: #8A7F78;
  --color-primary: #00D4FF;
  --color-accent: #FF6B00;
  --color-gold: #D4A843;
  --color-border: rgba(255,248,231,0.12);
  --color-border-strong: rgba(0,212,255,0.25);
  --color-shadow: rgba(0,0,0,0.5);
  --color-nav-bg: rgba(13,13,13,0.92);
  --color-nav-border: rgba(0,212,255,0.15);
  --color-footer-bg: #141414;
  --color-footer-border: rgba(255,248,231,0.06);

  /* 字体 */
  --font-heading: -apple-system, BlinkMacSystemFont, 'PingFang SC', 'Noto Sans SC', 'Microsoft YaHei', sans-serif;
  --font-body: -apple-system, BlinkMacSystemFont, 'PingFang SC', 'Noto Sans SC', 'Microsoft YaHei', sans-serif;
  --font-mono: 'SF Mono', 'JetBrains Mono', 'Fira Code', 'Cascadia Code', 'Courier New', monospace;

  /* 间距 (8px 网格) */
  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 32px;
  --space-5: 40px;
  --space-6: 48px;
  --space-8: 64px;
  --space-10: 80px;
  --space-12: 96px;

  /* 尺寸 */
  --header-height: 64px;
  --content-max-width: 1280px;
  --side-padding: clamp(16px, 5vw, 64px);
  --radius-sm: 4px;
  --radius-pill: 40px;

  /* 过渡 */
  --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* === REDUCED MOTION === */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { transition-duration: 0.01ms !important; animation-duration: 0.01ms !important; }
  html { scroll-behavior: auto; }
}

/* === SKIP LINK === */
.skip-link {
  position: fixed;
  top: var(--space-2);
  left: var(--space-2);
  z-index: 10000;
  padding: var(--space-1) var(--space-2);
  background: var(--color-primary);
  color: #0D0D0D;
  font-family: var(--font-body);
  font-weight: 700;
  font-size: 0.875rem;
  border-radius: var(--radius-sm);
  transform: translateY(-120%);
  transition: transform var(--transition-fast);
}
.skip-link:focus {
  transform: translateY(0);
}

/* === HEADER === */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  padding: var(--space-2) var(--side-padding) 0;
  pointer-events: none;
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: var(--space-1) var(--space-3);
  background: var(--color-nav-bg);
  border: 1px solid var(--color-nav-border);
  border-radius: var(--radius-pill);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  box-shadow: 0 4px 24px rgba(0,0,0,0.4);
  pointer-events: auto;
  transition: background var(--transition-base), border-color var(--transition-base);
}
.header-inner:hover {
  border-color: rgba(0,212,255,0.35);
}

/* 品牌 */
.brand {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex-shrink: 0;
}
.brand-icon {
  display: block;
  width: 28px;
  height: 28px;
  border: 2px solid var(--color-primary);
  border-radius: var(--radius-sm);
  position: relative;
  flex-shrink: 0;
  transition: border-color var(--transition-fast);
}
.brand-icon::after {
  content: '';
  position: absolute;
  top: 3px;
  left: 3px;
  width: 8px;
  height: 8px;
  background: var(--color-accent);
  border-radius: 1px;
  transition: background var(--transition-fast);
}
.brand:hover .brand-icon {
  border-color: var(--color-accent);
}
.brand:hover .brand-icon::after {
  background: var(--color-primary);
}
.brand-name {
  font-family: var(--font-heading);
  font-weight: 900;
  font-size: 1.25rem;
  letter-spacing: 0.04em;
  color: var(--color-text-light);
  white-space: nowrap;
}
.brand-name::after {
  content: '';
  display: inline-block;
  width: 4px;
  height: 4px;
  background: var(--color-accent);
  border-radius: 50%;
  margin-left: 6px;
  vertical-align: middle;
}

/* 导航 */
.nav-list {
  display: flex;
  align-items: center;
  gap: var(--space-1);
}
.nav-item {
  position: relative;
}
.nav-link {
  display: block;
  padding: var(--space-1) var(--space-2);
  font-family: var(--font-body);
  font-weight: 400;
  font-size: 0.875rem;
  letter-spacing: 0.03em;
  color: rgba(245,240,232,0.7);
  border-radius: var(--radius-pill);
  transition: color var(--transition-fast), background var(--transition-fast);
  white-space: nowrap;
}
.nav-link:hover,
.nav-link:focus-visible {
  color: var(--color-primary);
  background: rgba(0,212,255,0.08);
}
.nav-link[aria-current="page"] {
  color: var(--color-primary);
  background: rgba(0,212,255,0.1);
  box-shadow: inset 0 -1px 0 var(--color-primary);
}

/* 移动导航按钮 */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 36px;
  height: 36px;
  gap: 4px;
  padding: 4px;
  border-radius: var(--radius-sm);
  transition: background var(--transition-fast);
}
.nav-toggle:hover {
  background: rgba(0,212,255,0.08);
}
.nav-toggle-bar {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--color-text-light);
  border-radius: 1px;
  transition: transform var(--transition-fast), opacity var(--transition-fast);
}

/* 滚动进度条 */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  width: 0%;
  height: 2px;
  background: linear-gradient(90deg, var(--color-primary), var(--color-accent));
  z-index: 1001;
  pointer-events: none;
  transition: width 0.1s linear;
}
@media (prefers-reduced-motion: reduce) {
  .scroll-progress {
    transition: none;
  }
}

/* === 移动端导航 === */
@media (max-width: 767px) {
  .header-inner {
    padding: var(--space-1) var(--space-2);
    border-radius: var(--radius-pill);
    flex-wrap: wrap;
  }
  .nav-toggle {
    display: flex;
  }
  .nav {
    display: none;
    width: 100%;
    order: 3;
    padding-top: var(--space-2);
    border-top: 1px solid var(--color-nav-border);
    margin-top: var(--space-1);
  }
  [data-open] .nav {
    display: block;
  }
  [data-open] .nav-toggle-bar:nth-child(1) {
    transform: translateY(6px) rotate(45deg);
  }
  [data-open] .nav-toggle-bar:nth-child(2) {
    opacity: 0;
  }
  [data-open] .nav-toggle-bar:nth-child(3) {
    transform: translateY(-6px) rotate(-45deg);
  }
  .nav-list {
    flex-direction: column;
    gap: var(--space-1);
  }
  .nav-link {
    width: 100%;
    padding: var(--space-2) var(--space-2);
    font-size: 1rem;
    text-align: left;
  }
}

/* === 平板 === */
@media (min-width: 768px) and (max-width: 1024px) {
  .header-inner {
    padding: var(--space-1) var(--space-2);
  }
  .nav-link {
    padding: var(--space-1) var(--space-1);
    font-size: 0.8rem;
  }
}

/* === FOOTER === */
.site-footer {
  background: var(--color-footer-bg);
  border-top: 1px solid var(--color-footer-border);
  padding: var(--space-8) var(--side-padding) var(--space-4);
  margin-top: var(--space-10);
}
.footer-inner {
  max-width: var(--content-max-width);
  margin: 0 auto;
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1.5fr;
  gap: var(--space-6);
}
.footer-section {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}
.footer-heading {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 0.875rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  margin-bottom: var(--space-1);
}
.footer-brand .brand {
  margin-bottom: var(--space-1);
}
.footer-brand .brand-name {
  font-size: 1.125rem;
}
.footer-tagline {
  font-family: var(--font-body);
  font-weight: 300;
  font-size: 0.875rem;
  color: var(--color-text-muted);
  line-height: 1.5;
}
.footer-link-list,
.footer-contact-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}
.footer-link-list a,
.footer-contact-list a {
  font-family: var(--font-body);
  font-weight: 400;
  font-size: 0.875rem;
  color: rgba(245,240,232,0.6);
  transition: color var(--transition-fast);
  padding: 2px 0;
}
.footer-link-list a:hover,
.footer-contact-list a:hover {
  color: var(--color-primary);
}
.footer-contact-list li {
  font-family: var(--font-body);
  font-weight: 300;
  font-size: 0.875rem;
  color: rgba(245,240,232,0.5);
  line-height: 1.5;
}
.footer-trust {
  grid-column: 1 / -1;
  padding-top: var(--space-4);
  border-top: 1px solid var(--color-footer-border);
  margin-top: var(--space-2);
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  align-items: center;
  text-align: center;
}
.trust-statement {
  font-family: var(--font-body);
  font-weight: 300;
  font-size: 0.75rem;
  color: rgba(245,240,232,0.35);
  max-width: 480px;
}
.footer-copyright {
  font-family: var(--font-mono);
  font-weight: 400;
  font-size: 0.7rem;
  color: rgba(245,240,232,0.25);
  letter-spacing: 0.02em;
}

/* 页脚响应式 */
@media (max-width: 767px) {
  .footer-inner {
    grid-template-columns: 1fr;
    gap: var(--space-5);
  }
  .footer-trust {
    grid-column: 1;
  }
}
@media (min-width: 768px) and (max-width: 1024px) {
  .footer-inner {
    grid-template-columns: 1fr 1fr;
    gap: var(--space-5);
  }
  .footer-trust {
    grid-column: 1 / -1;
  }
}

/* === 通用容器 === */
.container {
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: 0 var(--side-padding);
}

/* === 通用按钮 === */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-1);
  padding: var(--space-1) var(--space-3);
  font-family: var(--font-body);
  font-weight: 600;
  font-size: 0.875rem;
  letter-spacing: 0.04em;
  color: var(--color-text-light);
  background: transparent;
  border: 1px solid var(--color-border-strong);
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
  cursor: pointer;
}
.btn:hover {
  border-color: var(--color-primary);
  background: rgba(0,212,255,0.06);
  box-shadow: 0 0 20px rgba(0,212,255,0.08);
}
.btn:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}
.btn-primary {
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: #0D0D0D;
  font-weight: 700;
}
.btn-primary:hover {
  background: transparent;
  color: var(--color-accent);
  border-color: var(--color-accent);
  box-shadow: 0 0 24px rgba(255,107,0,0.15);
}

/* === 面包屑 === */
.breadcrumb {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-1);
  padding: var(--space-2) 0;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--color-text-muted);
}
.breadcrumb a {
  color: var(--color-primary);
  transition: color var(--transition-fast);
}
.breadcrumb a:hover {
  color: var(--color-accent);
}
.breadcrumb-sep {
  color: var(--color-text-muted);
  margin: 0 var(--space-1);
}

/* === 网格 === */
.grid {
  display: grid;
  gap: var(--space-4);
}
.grid-col-2 {
  grid-template-columns: repeat(2, 1fr);
}
.grid-col-3 {
  grid-template-columns: repeat(3, 1fr);
}
@media (max-width: 767px) {
  .grid-col-2, .grid-col-3 {
    grid-template-columns: 1fr;
  }
}
@media (min-width: 768px) and (max-width: 1024px) {
  .grid-col-3 {
    grid-template-columns: repeat(2, 1fr);
  }
}

/* === 卡片 === */
.card {
  background: var(--color-surface);
  border: 1px solid rgba(44,30,22,0.08);
  border-radius: var(--radius-sm);
  padding: var(--space-4);
  transition: box-shadow var(--transition-fast), transform var(--transition-fast);
}
.card:hover {
  box-shadow: 0 8px 32px rgba(0,0,0,0.3);
  transform: translateY(-2px);
}
.card-title {
  font-family: var(--font-heading);
  font-weight: 900;
  font-size: 1.25rem;
  color: var(--color-text-dark);
  margin-bottom: var(--space-1);
}
.card-text {
  font-family: var(--font-body);
  font-weight: 300;
  font-size: 0.875rem;
  color: var(--color-text-muted);
  line-height: 1.7;
}

/* === 正文内容 === */
.content {
  font-family: var(--font-body);
  font-weight: 300;
  font-size: 1rem;
  color: var(--color-text-dark);
  line-height: 1.8;
  max-width: 720px;
}
.content h1, .content h2, .content h3 {
  font-family: var(--font-heading);
  font-weight: 900;
  color: var(--color-text-dark);
  margin-top: var(--space-6);
  margin-bottom: var(--space-2);
}
.content h1 { font-size: 2.5rem; letter-spacing: -0.02em; }
.content h2 { font-size: 1.75rem; border-bottom: 1px solid rgba(44,30,22,0.08); padding-bottom: var(--space-1); }
.content h3 { font-size: 1.25rem; }
.content p { margin-bottom: var(--space-3); }
.content a { color: var(--color-primary); border-bottom: 1px solid rgba(0,212,255,0.25); transition: border-color var(--transition-fast); }
.content a:hover { border-color: var(--color-accent); color: var(--color-accent); }
.content code, .content .mono {
  font-family: var(--font-mono);
  font-size: 0.875em;
  background: rgba(44,30,22,0.04);
  padding: 0.1em 0.3em;
  border-radius: 2px;
}
.content ul, .content ol {
  padding-left: var(--space-3);
  margin-bottom: var(--space-3);
}
.content ul { list-style: disc; }
.content ol { list-style: decimal; }
.content li { margin-bottom: var(--space-1); }

/* === 数字等宽 === */
.num, .data-value {
  font-family: var(--font-mono);
  font-feature-settings: "tnum" 1;
}

/* === 响应式图片容器 === */
.figure {
  position: relative;
  width: 100%;
  background: var(--color-surface-alt);
  border: 1px solid rgba(44,30,22,0.06);
  border-radius: var(--radius-sm);
  overflow: hidden;
  aspect-ratio: 16 / 9;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-muted);
  font-family: var(--font-mono);
  font-size: 0.75rem;
}
.figure img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

/* === 画册式分割线 === */
.divider {
  width: 100%;
  height: 1px;
  background: rgba(44,30,22,0.08);
  margin: var(--space-6) 0;
}

/* === 高亮标签 === */
.tag {
  display: inline-flex;
  align-items: center;
  padding: 2px var(--space-1);
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 500;
  border: 1px solid var(--color-border-strong);
  border-radius: 2px;
  color: var(--color-primary);
  background: rgba(0,212,255,0.04);
  letter-spacing: 0.04em;
}
.tag-accent {
  border-color: var(--color-accent);
  color: var(--color-accent);
  background: rgba(255,107,0,0.04);
}
.tag-gold {
  border-color: var(--color-gold);
  color: var(--color-gold);
  background: rgba(212,168,67,0.04);
}