/* Reset */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body { font-family: 'Roboto', 'PingFang SC', 'Microsoft YaHei', sans-serif; font-weight: 300; background-color: #121212; color: #B0BEC5; line-height: 1.7; min-height: 100vh; }
img, video { max-width: 100%; height: auto; display: block; }
a { color: inherit; text-decoration: none; }
ul { list-style: none; }

/* CSS Variables */
:root {
  --primary-blue: #0B1A2E;
  --primary-green: #00E676;
  --accent-orange: #FF6D00;
  --surface-dark: #121212;
  --surface-card: #1E1E1E;
  --text-primary: #FFFFFF;
  --text-secondary: #B0BEC5;
  --border-light: #2C3E50;
  --font-heading: 'Montserrat', 'PingFang SC', sans-serif;
  --font-body: 'Roboto', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --container-max: 1200px;
  --header-height: 64px;
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 2rem;
  --spacing-xl: 4rem;
}

/* Skip Link */
.skip-link {
  position: absolute; top: -100%; left: 0; z-index: 1000; background: var(--primary-green); color: #000; padding: 0.5rem 1rem; font-weight: 700; transition: top 0.3s;
}
.skip-link:focus { top: 0; }

/* Header */
.site-header {
  position: fixed; top: 0; left: 0; width: 100%; z-index: 100; height: var(--header-height);
  background: rgba(11,26,46,0.85); backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-light);
}
.header-inner {
  max-width: var(--container-max); margin: 0 auto; padding: 0 var(--spacing-md); height: 100%;
  display: flex; align-items: center; justify-content: space-between;
}
.site-logo {
  display: flex; align-items: center; gap: var(--spacing-sm); font-family: var(--font-heading); font-weight: 900; font-size: 1.25rem; color: var(--text-primary); letter-spacing: 0.05em;
}
.logo-icon { width: 32px; height: 32px; background: linear-gradient(135deg, var(--primary-green), var(--accent-orange)); border-radius: 50%; display: inline-block; }
.logo-text { color: var(--text-primary); }
.nav-toggle { display: none; background: none; border: none; cursor: pointer; padding: 0.25rem; }
.nav-toggle-line { display: block; width: 24px; height: 2px; background: var(--text-primary); margin: 4px 0; transition: all 0.3s; }
@media (max-width: 768px) {
  .nav-toggle { display: block; }
  .site-nav {
    position: fixed; top: var(--header-height); left: 0; width: 100%; background: var(--primary-blue); padding: var(--spacing-md); transform: translateY(-100%); opacity: 0; transition: all 0.3s; pointer-events: none;
  }
  .site-nav[data-open] { transform: translateY(0); opacity: 1; pointer-events: auto; }
  .nav-list { flex-direction: column; gap: var(--spacing-md); }
}
.site-nav[data-open] + .nav-toggle .nav-toggle-line:nth-child(1) { transform: rotate(45deg) translate(4px, 4px); }
.site-nav[data-open] + .nav-toggle .nav-toggle-line:nth-child(2) { opacity: 0; }
.site-nav[data-open] + .nav-toggle .nav-toggle-line:nth-child(3) { transform: rotate(-45deg) translate(4px, -4px); }

.nav-list { display: flex; gap: var(--spacing-lg); align-items: center; }
.nav-link {
  font-family: var(--font-heading); font-weight: 700; font-size: 0.9rem; text-transform: uppercase; letter-spacing: 0.05em; color: var(--text-secondary); padding: 0.25rem 0; border-bottom: 2px solid transparent; transition: color 0.2s, border-color 0.2s;
}
.nav-link:hover, .nav-link:focus-visible { color: var(--text-primary); }
.nav-link[aria-current="page"] { color: var(--primary-green); border-bottom-color: var(--primary-green); }

/* Progress Bar */
.progress-bar {
  position: fixed; top: var(--header-height); left: 0; width: 0%; height: 3px; background: linear-gradient(90deg, var(--primary-green), var(--accent-orange)); z-index: 101; transition: width 0.1s linear; will-change: width;
}
@media (prefers-reduced-motion: reduce) { .progress-bar { display: none; } }

/* Footer */
.site-footer {
  background: var(--primary-blue); border-top: 1px solid var(--border-light); padding: var(--spacing-xl) 0; margin-top: var(--spacing-xl);
}
.footer-inner {
  max-width: var(--container-max); margin: 0 auto; padding: 0 var(--spacing-md); display: grid; grid-template-columns: 1fr 2fr 1fr; gap: var(--spacing-lg); align-items: start;
}
@media (max-width: 768px) { .footer-inner { grid-template-columns: 1fr; text-align: center; gap: var(--spacing-md); } }
.footer-logo { font-family: var(--font-heading); font-weight: 900; font-size: 1.5rem; color: var(--text-primary); }
.footer-tagline { font-size: 0.85rem; color: var(--text-secondary); margin-top: var(--spacing-sm); }
.footer-contact, .footer-address { font-size: 0.9rem; color: var(--text-secondary); line-height: 1.8; }
.footer-contact a { color: var(--primary-green); text-decoration: underline; }
.footer-links { display: flex; gap: var(--spacing-md); justify-content: flex-end; flex-wrap: wrap; }
@media (max-width: 768px) { .footer-links { justify-content: center; } }
.footer-links a { font-size: 0.9rem; color: var(--text-secondary); transition: color 0.2s; }
.footer-links a:hover { color: var(--primary-green); }
.footer-icp { grid-column: 1 / -1; text-align: center; font-size: 0.8rem; color: var(--text-secondary); margin-top: var(--spacing-md); border-top: 1px solid var(--border-light); padding-top: var(--spacing-md); }

/* Common Components */
.container { max-width: var(--container-max); margin: 0 auto; padding: 0 var(--spacing-md); }
.section-title { font-family: var(--font-heading); font-weight: 900; font-size: 2.5rem; color: var(--text-primary); margin-bottom: var(--spacing-lg); position: relative; display: inline-block; }
.section-title::after { content: ''; display: block; width: 60px; height: 4px; background: var(--primary-green); margin-top: var(--spacing-sm); }
.btn {
  display: inline-flex; align-items: center; justify-content: center; padding: 0.75rem 1.5rem; font-family: var(--font-heading); font-weight: 700; font-size: 0.9rem; border: none; cursor: pointer; border-radius: 4px; transition: all 0.2s; text-transform: uppercase; letter-spacing: 0.05em;
}
.btn-primary { background: var(--primary-green); color: #000; }
.btn-primary:hover, .btn-primary:focus-visible { background: #00c853; }
.btn-accent { background: var(--accent-orange); color: #fff; }
.btn-accent:hover, .btn-accent:focus-visible { background: #e65100; }
.card {
  background: var(--surface-card); border: 1px solid var(--border-light); border-radius: 8px; padding: var(--spacing-lg); transition: transform 0.3s, box-shadow 0.3s;
}
.card:hover { transform: translateY(-4px); box-shadow: 0 8px 24px rgba(0,0,0,0.4); }
.frame-window {
  position: relative; border: 2px solid var(--border-light); border-radius: 4px; overflow: hidden; background: var(--primary-blue); padding: var(--spacing-lg); 
  clip-path: polygon(0% 0%, 100% 0%, 100% calc(100% - 16px), calc(100% - 16px) 100%, 0% 100%);
}
.frame-window::before { content: ''; position: absolute; top: 8px; right: 8px; width: 12px; height: 12px; border-right: 2px solid var(--primary-green); border-top: 2px solid var(--primary-green); }
.status-panel { background: var(--surface-card); border-left: 4px solid var(--primary-green); padding: var(--spacing-md); border-radius: 0 4px 4px 0; }

/* Reveal animation classes (controlled by JS) */
.reveal { opacity: 0; transform: translateY(30px); transition: opacity 0.6s ease, transform 0.6s ease; }
.reveal.visible { opacity: 1; transform: translateY(0); }
@media (prefers-reduced-motion: reduce) { .reveal { opacity: 1; transform: none; transition: none; } }

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

/* Responsive utilities */
@media (max-width: 1024px) { :root { --header-height: 60px; } }
@media (max-width: 480px) { .section-title { font-size: 1.75rem; } }