/* Reset */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body { margin: 0; font-family: 'Helvetica Neue', Helvetica, Arial, 'PingFang SC', 'Microsoft YaHei', sans-serif; background: #1A2A3A; color: #FFFFFF; line-height: 1.6; }

/* Variables */
:root {
  --color-deep-blue: #1A2A3A;
  --color-orange: #FF6B35;
  --color-green: #39FF14;
  --color-dark-teal: #0B3D3D;
  --color-wine: #8B0000;
  --color-indigo: #4B0082;
  --color-light-gray: #F5F5F5;
  --color-white: #FFFFFF;
  --color-dark-gray: #333333;
  --font-heading: 'Helvetica Neue', Helvetica, Arial, sans-serif;
  --font-body: 'Helvetica Neue', Helvetica, Arial, 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-mono: 'Courier New', 'Fira Code', monospace;
  --header-height: 60px;
  --content-max-width: 1280px;
  --breakpoint-mobile: 768px;
  --breakpoint-tablet: 1024px;
}

/* Skip Link */
.skip-link {
  position: absolute;
  top: -100px;
  left: 0;
  background: var(--color-orange);
  color: var(--color-white);
  padding: 0.5rem 1rem;
  z-index: 9999;
  font-weight: bold;
}
.skip-link:focus { top: 0; }

/* Header */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: var(--header-height);
  background: rgba(26, 42, 58, 0.9);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  z-index: 1000;
  transition: background 0.3s;
}
.header-inner {
  max-width: var(--content-max-width);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  padding: 0 1.5rem;
}
.brand {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1.6rem;
  color: var(--color-white);
  text-decoration: none;
  letter-spacing: 2px;
  background: linear-gradient(135deg, var(--color-orange), var(--color-green));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.nav-toggle {
  display: none;
  background: none;
  border: none;
  padding: 0.5rem;
  cursor: pointer;
  position: relative;
  z-index: 2000;
}
.nav-toggle-icon {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-white);
  transition: all 0.3s;
}
.nav-toggle-icon::before,
.nav-toggle-icon::after {
  content: '';
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-white);
  transition: all 0.3s;
  transform: translateY(-6px);
}
.nav-toggle-icon::after { transform: translateY(4px); }
[data-nav-toggle][aria-expanded="true"] .nav-toggle-icon { background: transparent; }
[data-nav-toggle][aria-expanded="true"] .nav-toggle-icon::before { transform: translateY(0) rotate(45deg); }
[data-nav-toggle][aria-expanded="true"] .nav-toggle-icon::after { transform: translateY(-2px) rotate(-45deg); }

.site-nav ul {
  list-style: none;
  display: flex;
  gap: 2rem;
  align-items: center;
}
.site-nav a {
  color: var(--color-white);
  text-decoration: none;
  font-family: var(--font-body);
  font-weight: 500;
  padding: 0.25rem 0;
  position: relative;
  transition: color 0.2s;
}
.site-nav a::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--color-orange);
  transition: width 0.3s;
}
.site-nav a:hover,
.site-nav a:focus-visible { color: var(--color-orange); }
.site-nav a:hover::after,
.site-nav a:focus-visible::after { width: 100%; }
.site-nav a[aria-current="page"] { color: var(--color-orange); }
.site-nav a[aria-current="page"]::after { width: 100%; }

/* Progress Bar */
[data-progress-bar] {
  position: fixed;
  top: var(--header-height);
  left: 0;
  height: 3px;
  background: var(--color-green);
  width: 0%;
  z-index: 999;
  transition: width 0.1s linear;
}
@media (prefers-reduced-motion: reduce) {
  [data-progress-bar] { transition: none; }
}

/* Footer */
.site-footer {
  background: var(--color-deep-blue);
  color: #ccc;
  padding: 3rem 1.5rem 1rem;
}
.footer-inner {
  max-width: var(--content-max-width);
  margin: 0 auto;
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1.5fr;
  gap: 2rem;
}
.footer-col h4 {
  color: var(--color-white);
  margin-bottom: 1rem;
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1.1rem;
}
.footer-col ul { list-style: none; }
.footer-col li { margin-bottom: 0.5rem; }
.footer-col a {
  color: #ccc;
  text-decoration: none;
  transition: color 0.2s;
}
.footer-col a:hover,
.footer-col a:focus-visible { color: var(--color-orange); }
.footer-brand {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1.4rem;
  color: var(--color-white);
  text-decoration: none;
  background: linear-gradient(135deg, var(--color-orange), var(--color-green));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  display: inline-block;
  margin-bottom: 0.5rem;
}
.footer-trust { font-size: 0.9rem; line-height: 1.5; margin-top: 0.5rem; color: #aaa; }
.contact-list li { font-size: 0.95rem; }
.contact-list a { color: var(--color-green); }
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.1);
  margin-top: 2rem;
  padding-top: 1rem;
  text-align: center;
  font-size: 0.85rem;
  color: #999;
}

/* Content Container */
.content-container {
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* Buttons */
.btn {
  display: inline-block;
  background: var(--color-orange);
  color: var(--color-white);
  padding: 0.75rem 1.5rem;
  border: none;
  border-radius: 4px;
  font-family: var(--font-body);
  font-weight: 700;
  font-size: 1rem;
  text-decoration: none;
  cursor: pointer;
  transition: background 0.2s, transform 0.1s;
}
.btn:hover,
.btn:focus-visible { background: #e55a2b; transform: translateY(-1px); }
.btn:active { transform: translateY(0); }

/* Breadcrumb */
.breadcrumb {
  display: flex;
  gap: 0.5rem;
  list-style: none;
  padding: 0.5rem 0;
  font-size: 0.9rem;
  color: #aaa;
}
.breadcrumb li + li::before {
  content: '/';
  margin-right: 0.5rem;
  color: var(--color-indigo);
}
.breadcrumb a { color: var(--color-orange); text-decoration: none; }

/* Base Card */
.card {
  background: var(--color-white);
  color: var(--color-dark-gray);
  border-radius: 8px;
  padding: 1.5rem;
  box-shadow: 0 2px 8px rgba(0,0,0,0.15);
  transition: box-shadow 0.3s, transform 0.3s;
}
.card:hover { box-shadow: 0 6px 20px rgba(0,0,0,0.25); transform: translateY(-2px); }
.card img { max-width: 100%; height: auto; }

/* Responsive Image Container */
.img-container {
  position: relative;
  overflow: hidden;
  background: linear-gradient(135deg, var(--color-dark-teal), var(--color-indigo));
}
.img-container::before { content: ''; display: block; padding-bottom: 56.25%; }
.img-container > img, .img-container > .placeholder {
  position: absolute;
  top: 0; left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

/* Utility Grid */
.grid {
  display: grid;
  gap: 1.5rem;
}
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

/* Responsive */
@media (max-width: 768px) {
  .nav-toggle { display: block; }
  .site-nav {
    position: fixed;
    top: var(--header-height);
    left: 0;
    width: 100%;
    background: rgba(26, 42, 58, 0.98);
    backdrop-filter: blur(8px);
    padding: 1rem;
    transform: translateY(-100%);
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    max-height: calc(100vh - var(--header-height));
    overflow-y: auto;
  }
  .site-nav[data-open] {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }
  .site-nav ul { flex-direction: column; gap: 1rem; }
  .site-nav a { font-size: 1.1rem; padding: 0.5rem 0; }
  .footer-inner { grid-template-columns: 1fr; gap: 1.5rem; }
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
}

@media (min-width: 769px) and (max-width: 1024px) {
  .footer-inner { grid-template-columns: 1fr 1fr; }
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
}

/* Focus visible */
:focus-visible { outline: 2px solid var(--color-orange); outline-offset: 2px; }

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