/* ===== 重置 & 变量 ===== */
*,
*::before,
*::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --color-primary-bg: #0A192F;
  --color-primary-text: #FFFFFF;
  --color-accent-gold: #FFD700;
  --color-accent-cyan: #00E5FF;
  --color-accent-purple: #B388FF;
  --color-neutral-light: #F5F5F5;
  --color-neutral-dark: #1A1A1A;
  --color-chart-green: #4CAF50;
  --color-divider: #2A3F5E;
  --color-text-muted: #8899AA;
  --color-text-body: #E0E0E0;
  --font-heading: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-caption: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-special: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --fw-heading: 700;
  --fw-body: 400;
  --fw-caption: 300;
  --fw-special: 500;
  --fs-heading-xl: clamp(2.75rem, 6vw, 6rem);
  --fs-heading-lg: clamp(2rem, 4vw, 3.5rem);
  --fs-heading-md: clamp(1.5rem, 3vw, 2.25rem);
  --fs-heading-sm: clamp(1.125rem, 1.8vw, 1.5rem);
  --fs-body: clamp(0.9375rem, 1.2vw, 1rem);
  --fs-caption: 0.75rem;
  --fs-special: 0.875rem;
  --lh-body: 1.6;
  --ls-heading: -0.02em;
  --ls-special: 0.05em;
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 2rem;
  --spacing-xl: 4rem;
  --spacing-2xl: 6rem;
  --border-radius: 4px;
  --transition-fast: 0.2s ease;
  --transition-base: 0.35s ease;
  --shadow-card: 0 2px 12px rgba(0,0,0,0.25);
  --max-width: 1200px;
  --header-top-height: 2rem;
  --header-main-height: 4rem;
}

html { scroll-behavior: smooth; font-size: 100%; }

body {
  font-family: var(--font-body);
  font-weight: var(--fw-body);
  font-size: var(--fs-body);
  line-height: var(--lh-body);
  color: var(--color-text-body);
  background-color: var(--color-primary-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img, svg { max-width: 100%; display: block; }
a { color: var(--color-accent-cyan); text-decoration: none; transition: color var(--transition-fast); }
a:hover { color: var(--color-accent-gold); }
a:focus-visible { outline: 2px solid var(--color-accent-gold); outline-offset: 2px; border-radius: 2px; }
ul, ol { list-style: none; }
button { font: inherit; color: inherit; cursor: pointer; border: none; background: none; }
input, textarea { font: inherit; color: inherit; }

/* ===== 滚动进度条 ===== */
#scroll-progress {
  position: fixed;
  top: 0; left: 0;
  width: 0%;
  height: 3px;
  background: var(--color-accent-cyan);
  z-index: 9999;
  pointer-events: none;
  transition: width 0.1s linear;
}

/* ===== 跳过链接 ===== */
.skip-link {
  position: absolute;
  top: -100%;
  left: var(--spacing-md);
  padding: var(--spacing-sm) var(--spacing-md);
  background: var(--color-accent-gold);
  color: var(--color-neutral-dark);
  font-weight: var(--fw-heading);
  font-size: var(--fs-special);
  z-index: 10000;
  border-radius: 0 0 var(--border-radius) var(--border-radius);
  transition: top var(--transition-fast);
}
.skip-link:focus { top: 0; }

/* ===== 头部 ===== */
.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 1000;
  background: rgba(10, 25, 47, 0.95);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--color-divider);
  transition: background var(--transition-base), box-shadow var(--transition-base);
}
.site-header.scrolled {
  background: rgba(10, 25, 47, 0.98);
  box-shadow: 0 2px 20px rgba(0,0,0,0.4);
}

.header-top {
  height: var(--header-top-height);
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(255, 215, 0, 0.06);
  border-bottom: 1px solid rgba(255, 215, 0, 0.08);
  padding: 0 var(--spacing-md);
  overflow: hidden;
}
.header-tagline {
  font-family: var(--font-special);
  font-weight: var(--fw-caption);
  font-size: 0.7rem;
  letter-spacing: var(--ls-special);
  color: var(--color-text-muted);
  text-transform: uppercase;
  white-space: nowrap;
}
.header-main {
  height: var(--header-main-height);
  display: flex;
  align-items: center;
}
.header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
  width: 100%;
  display: flex;
  align-items: center;
  gap: var(--spacing-lg);
  height: 100%;
}

.brand-logo {
  font-family: var(--font-heading);
  font-weight: var(--fw-heading);
  font-size: var(--fs-heading-sm);
  color: var(--color-accent-gold);
  letter-spacing: var(--ls-heading);
  flex-shrink: 0;
  transition: opacity var(--transition-fast);
}
.brand-logo:hover { color: var(--color-accent-gold); opacity: 0.85; }

.nav-primary {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: var(--spacing-lg);
}
.nav-list {
  display: flex;
  align-items: center;
  gap: var(--spacing-lg);
}
.nav-link {
  font-family: var(--font-special);
  font-weight: var(--fw-special);
  font-size: var(--fs-special);
  letter-spacing: var(--ls-special);
  color: var(--color-primary-text);
  position: relative;
  padding: var(--spacing-xs) 0;
  transition: color var(--transition-fast);
  text-transform: uppercase;
}
.nav-link::after {
  content: '';
  position: absolute;
  bottom: -2px; left: 0;
  width: 0%;
  height: 2px;
  background: var(--color-accent-gold);
  transition: width var(--transition-base);
}
.nav-link:hover { color: var(--color-accent-gold); }
.nav-link:hover::after { width: 100%; }
.nav-link[aria-current="page"] {
  color: var(--color-accent-gold);
}
.nav-link[aria-current="page"]::after {
  width: 100%;
  background: var(--color-accent-gold);
}

.search-bar {
  display: flex;
  align-items: center;
}
.search-bar input {
  background: rgba(255,255,255,0.06);
  border: 1px solid var(--color-divider);
  border-radius: var(--border-radius);
  padding: 0.35rem 0.75rem;
  font-size: var(--fs-caption);
  color: var(--color-primary-text);
  width: 140px;
  transition: border-color var(--transition-fast), width var(--transition-base);
  font-family: var(--font-body);
}
.search-bar input::placeholder { color: var(--color-text-muted); }
.search-bar input:focus {
  outline: none;
  border-color: var(--color-accent-cyan);
  width: 200px;
}

/* 移动端导航按钮 */
.mobile-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 2.25rem;
  height: 2.25rem;
  gap: 4px;
  padding: 4px;
  border-radius: var(--border-radius);
  transition: background var(--transition-fast);
}
.mobile-toggle:hover { background: rgba(255,255,255,0.05); }
.toggle-bar {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--color-primary-text);
  border-radius: 1px;
  transition: transform var(--transition-base), opacity var(--transition-base);
}
.mobile-toggle[aria-expanded="true"] .toggle-bar:nth-child(1) {
  transform: translateY(6px) rotate(45deg);
}
.mobile-toggle[aria-expanded="true"] .toggle-bar:nth-child(2) {
  opacity: 0;
}
.mobile-toggle[aria-expanded="true"] .toggle-bar:nth-child(3) {
  transform: translateY(-6px) rotate(-45deg);
}

/* ===== 页脚 ===== */
.site-footer {
  background: var(--color-primary-bg);
  border-top: 1px solid var(--color-divider);
  padding: var(--spacing-xl) 0 var(--spacing-lg);
  margin-top: var(--spacing-2xl);
}
.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}
.footer-brand {
  margin-bottom: var(--spacing-xl);
  text-align: center;
}
.brand-logo--footer {
  font-size: var(--fs-heading-md);
  display: inline-block;
}
.footer-tagline {
  font-family: var(--font-special);
  font-weight: var(--fw-caption);
  font-size: var(--fs-caption);
  color: var(--color-text-muted);
  letter-spacing: var(--ls-special);
  text-transform: uppercase;
  margin-top: var(--spacing-xs);
}

.footer-columns {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-xl);
}
.footer-column { min-width: 0; }
.footer-heading {
  font-family: var(--font-heading);
  font-weight: var(--fw-heading);
  font-size: var(--fs-heading-sm);
  color: var(--color-accent-gold);
  letter-spacing: var(--ls-heading);
  margin-bottom: var(--spacing-md);
  padding-bottom: var(--spacing-sm);
  border-bottom: 1px solid var(--color-divider);
}
.footer-links {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}
.footer-links a {
  font-size: var(--fs-special);
  color: var(--color-text-body);
  transition: color var(--transition-fast), padding-left var(--transition-fast);
}
.footer-links a:hover {
  color: var(--color-accent-cyan);
  padding-left: 4px;
}

.footer-legal {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: var(--spacing-md);
  padding: var(--spacing-lg) 0;
  border-top: 1px solid var(--color-divider);
  border-bottom: 1px solid var(--color-divider);
  margin-bottom: var(--spacing-lg);
  flex-wrap: wrap;
}
.footer-legal a {
  font-family: var(--font-special);
  font-weight: var(--fw-special);
  font-size: var(--fs-special);
  color: var(--color-text-muted);
  letter-spacing: var(--ls-special);
  text-transform: uppercase;
  transition: color var(--transition-fast);
}
.footer-legal a:hover { color: var(--color-accent-gold); }
.legal-divider { color: var(--color-divider); font-size: var(--fs-caption); }

.footer-contact {
  text-align: center;
  margin-bottom: var(--spacing-lg);
}
.footer-contact p {
  font-size: var(--fs-caption);
  color: var(--color-text-muted);
  line-height: 2;
}
.footer-contact a { color: var(--color-accent-cyan); }
.footer-contact a:hover { color: var(--color-accent-gold); }
.footer-note {
  font-style: italic;
  color: var(--color-text-muted);
  margin-top: var(--spacing-sm);
  font-size: var(--fs-caption);
}

.footer-icp {
  text-align: center;
  padding-top: var(--spacing-lg);
  border-top: 1px solid var(--color-divider);
}
.footer-icp p {
  font-size: var(--fs-caption);
  color: var(--color-text-muted);
  line-height: 1.8;
}
.footer-trust {
  font-weight: var(--fw-body);
  color: var(--color-text-body);
  margin-bottom: var(--spacing-sm);
}

/* ===== 通用组件 ===== */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

.content {
  max-width: 720px;
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

.section {
  padding: var(--spacing-2xl) 0;
}

.section-title {
  font-family: var(--font-heading);
  font-weight: var(--fw-heading);
  font-size: var(--fs-heading-lg);
  color: var(--color-primary-text);
  letter-spacing: var(--ls-heading);
  margin-bottom: var(--spacing-lg);
  position: relative;
  display: inline-block;
}
.section-title::after {
  content: '';
  display: block;
  width: 60px;
  height: 3px;
  background: var(--color-accent-gold);
  margin-top: var(--spacing-sm);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.6rem 1.8rem;
  font-family: var(--font-special);
  font-weight: var(--fw-special);
  font-size: var(--fs-special);
  letter-spacing: var(--ls-special);
  text-transform: uppercase;
  border-radius: var(--border-radius);
  transition: background var(--transition-fast), color var(--transition-fast), transform var(--transition-fast), box-shadow var(--transition-fast);
  cursor: pointer;
  border: 1px solid transparent;
}
.btn:focus-visible {
  outline: 2px solid var(--color-accent-gold);
  outline-offset: 2px;
}
.btn--gold {
  background: var(--color-accent-gold);
  color: var(--color-neutral-dark);
  border-color: var(--color-accent-gold);
}
.btn--gold:hover {
  background: transparent;
  color: var(--color-accent-gold);
  transform: scale(1.05);
  box-shadow: 0 0 20px rgba(255, 215, 0, 0.15);
}
.btn--outline {
  background: transparent;
  color: var(--color-accent-cyan);
  border-color: var(--color-accent-cyan);
}
.btn--outline:hover {
  background: var(--color-accent-cyan);
  color: var(--color-neutral-dark);
  transform: scale(1.05);
}

.grid {
  display: grid;
  gap: var(--spacing-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); }

.card {
  background: rgba(255,255,255,0.03);
  border: 1px solid var(--color-divider);
  border-radius: var(--border-radius);
  padding: var(--spacing-lg);
  transition: transform var(--transition-base), box-shadow var(--transition-base), border-color var(--transition-base);
}
.card:hover {
  transform: scale(1.02);
  box-shadow: var(--shadow-card);
  border-color: var(--color-accent-gold);
}
.card-title {
  font-family: var(--font-heading);
  font-weight: var(--fw-heading);
  font-size: var(--fs-heading-sm);
  color: var(--color-primary-text);
  margin-bottom: var(--spacing-sm);
  letter-spacing: var(--ls-heading);
}
.card-text {
  font-size: var(--fs-body);
  color: var(--color-text-body);
  line-height: var(--lh-body);
}

/* 框景容器（首页首屏） */
.framed-viewport {
  position: relative;
  border: 2px solid var(--color-divider);
  padding: var(--spacing-xl);
  background: rgba(255,255,255,0.02);
  min-height: 60vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
}
.framed-viewport::before,
.framed-viewport::after {
  content: '';
  position: absolute;
  pointer-events: none;
}
.framed-viewport::before {
  top: -1px; left: 10%;
  width: 80%;
  height: 1px;
  background: var(--color-accent-gold);
  opacity: 0.3;
}
.framed-viewport::after {
  bottom: -1px; right: 10%;
  width: 80%;
  height: 1px;
  background: var(--color-accent-gold);
  opacity: 0.3;
}

/* 对角线分割 */
.diagonal-divider {
  height: 2px;
  background: linear-gradient(135deg, transparent 0%, var(--color-accent-gold) 50%, var(--color-accent-cyan) 100%);
  margin: var(--spacing-xl) 0;
  opacity: 0.4;
}

/* 图片占位容器 */
.img-placeholder {
  background: rgba(255,255,255,0.03);
  border: 1px dashed var(--color-divider);
  border-radius: var(--border-radius);
  aspect-ratio: 16 / 9;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-muted);
  font-size: var(--fs-caption);
  overflow: hidden;
}
.img-placeholder > svg {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

/* 面包屑 */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-md) 0;
  font-size: var(--fs-caption);
  color: var(--color-text-muted);
  flex-wrap: wrap;
}
.breadcrumb-link {
  color: var(--color-accent-cyan);
  transition: color var(--transition-fast);
}
.breadcrumb-link:hover { color: var(--color-accent-gold); }
.breadcrumb-current {
  color: var(--color-primary-text);
  font-weight: var(--fw-body);
}
.breadcrumb-sep {
  color: var(--color-divider);
  user-select: none;
}

/* 返回顶部 */
.scroll-top {
  position: fixed;
  bottom: var(--spacing-lg);
  right: var(--spacing-lg);
  width: 2.75rem;
  height: 2.75rem;
  border-radius: 50%;
  background: var(--color-accent-gold);
  color: var(--color-neutral-dark);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  box-shadow: 0 2px 12px rgba(255,215,0,0.2);
  opacity: 0;
  transform: translateY(20px);
  pointer-events: none;
  transition: opacity var(--transition-base), transform var(--transition-base), background var(--transition-fast);
  z-index: 900;
}
.scroll-top.is-visible {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}
.scroll-top:hover {
  background: var(--color-accent-cyan);
  color: var(--color-neutral-dark);
  transform: translateY(-2px);
}

/* 滚动显现 */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
.reveal--visible {
  opacity: 1;
  transform: translateY(0);
}

/* ===== 响应式 ===== */
@media (max-width: 1024px) {
  .footer-columns {
    grid-template-columns: repeat(3, 1fr);
  }
}

@media (max-width: 768px) {
  :root {
    --header-top-height: 1.75rem;
    --header-main-height: 3.5rem;
  }
  .header-inner {
    padding: 0 var(--spacing-md);
    gap: var(--spacing-sm);
  }
  .brand-logo {
    font-size: var(--fs-heading-sm);
  }
  .mobile-toggle {
    display: flex;
  }
  .nav-primary {
    position: fixed;
    top: calc(var(--header-top-height) + var(--header-main-height));
    left: 0; right: 0;
    background: rgba(10, 25, 47, 0.98);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    flex-direction: column;
    padding: var(--spacing-lg);
    gap: var(--spacing-lg);
    border-bottom: 1px solid var(--color-divider);
    transform: translateY(-120%);
    opacity: 0;
    transition: transform 0.4s ease, opacity 0.4s ease;
    pointer-events: none;
    max-height: 80vh;
    overflow-y: auto;
  }
  .nav-primary[data-open] {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }
  .nav-list {
    flex-direction: column;
    gap: var(--spacing-md);
    width: 100%;
  }
  .nav-link {
    font-size: var(--fs-body);
    padding: var(--spacing-sm) 0;
    display: block;
    width: 100%;
  }
  .search-bar {
    width: 100%;
  }
  .search-bar input {
    width: 100%;
  }
  .search-bar input:focus {
    width: 100%;
  }

  .footer-columns {
    grid-template-columns: repeat(2, 1fr);
  }
  .footer-legal {
    flex-direction: column;
    gap: var(--spacing-sm);
  }
  .legal-divider { display: none; }

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

  .framed-viewport {
    padding: var(--spacing-lg);
    min-height: 50vh;
  }

  .section-title {
    font-size: var(--fs-heading-md);
  }
}

@media (max-width: 480px) {
  .footer-columns {
    grid-template-columns: 1fr;
  }
  .header-tagline {
    font-size: 0.6rem;
  }
}

/* ===== prefers-reduced-motion ===== */
@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;
  }
  .reveal {
    opacity: 1;
    transform: none;
  }
  .scroll-top {
    transition: opacity 0.01ms ease;
  }
  .card:hover {
    transform: none;
  }
  .nav-link::after {
    transition: none;
  }
}

/* ===== focus-visible 全局 ===== */
:focus-visible {
  outline: 2px solid var(--color-accent-gold);
  outline-offset: 2px;
}

/* ===== 选择高亮 ===== */
::selection {
  background: var(--color-accent-gold);
  color: var(--color-neutral-dark);
}