/* Reset & Base */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body { font-family: 'Inter', 'Noto Sans SC', system-ui, -apple-system, sans-serif; background: #0D1B2A; color: #F5F5F5; line-height: 1.6; min-height: 100vh; overflow-x: hidden; }
a { color: #00FF87; text-decoration: none; transition: color 0.2s; }
a:hover, a:focus-visible { color: #FFD700; }
a:focus-visible { outline: 2px solid #FFD700; outline-offset: 2px; }
img, svg { max-width: 100%; height: auto; display: block; }
ul, ol { list-style: none; }
h1, h2, h3, h4 { font-weight: 700; color: #FFFFFF; }
h1 { font-size: 2.5rem; letter-spacing: -0.02em; }
h2 { font-size: 1.8rem; }
h3 { font-size: 1.25rem; }
.data-font { font-family: 'JetBrains Mono', 'SF Mono', 'Menlo', monospace; }

/* Variables */
:root {
  --bg-deep: #0D1B2A;
  --bg-card: #1B2838;
  --bg-mid: #162233;
  --accent-green: #00FF87;
  --accent-gold: #FFD700;
  --text-primary: #F5F5F5;
  --text-secondary: #B0B0B0;
  --text-white: #FFFFFF;
  --border-radius: 16px;
  --header-height: 72px;
  --content-max: 1200px;
  --content-narrow: 780px;
  --spacing-section: 4rem;
}

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

/* Skip link */
.skip-link { position: absolute; top: -999px; left: 50%; transform: translateX(-50%); background: var(--accent-green); color: #0D1B2A; padding: 0.5rem 1rem; z-index: 1000; border-radius: 0 0 8px 8px; font-weight: 600; }
.skip-link:focus-visible { top: 0; }

/* Header */
.site-header { position: fixed; top: 0; left: 0; right: 0; z-index: 500; background: #0D1B2A; border-bottom: 1px solid rgba(0,255,135,0.15); }
.header-inner { display: flex; align-items: center; justify-content: space-between; max-width: var(--content-max); margin: 0 auto; padding: 0 1.5rem; height: var(--header-height); }
.brand { display: flex; align-items: center; gap: 0.5rem; color: var(--text-white); font-weight: 700; font-size: 1.25rem; }
.brand-icon { color: var(--accent-gold); font-size: 1.1em; }
.brand-name { letter-spacing: 0.02em; }
.nav-toggle { display: none; background: none; border: none; cursor: pointer; padding: 0.5rem; flex-direction: column; justify-content: center; gap: 4px; width: 32px; height: 32px; }
.nav-toggle-bar { display: block; width: 100%; height: 2px; background: var(--accent-green); border-radius: 2px; transition: all 0.3s; }
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(1) { transform: rotate(45deg) translate(4px,4px); }
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(3) { transform: rotate(-45deg) translate(4px,-4px); }
.site-nav { display: flex; }
.nav-list { display: flex; gap: 1.5rem; }
.nav-link { color: var(--text-secondary); font-size: 0.9375rem; font-weight: 500; padding: 0.5rem 0; border-bottom: 2px solid transparent; transition: all 0.2s; }
.nav-link:hover, .nav-link:focus-visible { color: var(--accent-green); }
.nav-link[aria-current="page"] { color: var(--accent-green); border-bottom-color: var(--accent-green); }

/* Scroll progress */
.header-progress { position: absolute; bottom: 0; left: 0; height: 2px; background: var(--accent-gold); width: 0%; transition: width 50ms linear; z-index: 1; }

/* Footer */
.site-footer { background: #0B1A2A; border-top: 1px solid rgba(255,215,0,0.2); padding: 3rem 1.5rem 1.5rem; margin-top: var(--spacing-section); }
.footer-inner { max-width: var(--content-max); margin: 0 auto; }
.footer-brand .brand { font-size: 1.125rem; margin-bottom: 1rem; }
.footer-links { display: flex; gap: 2rem; margin: 1.5rem 0; flex-wrap: wrap; }
.footer-links a { color: var(--text-secondary); font-size: 0.9375rem; }
.footer-links a:hover { color: var(--accent-gold); }
.footer-contact { display: flex; flex-wrap: wrap; gap: 1rem 2rem; color: var(--text-secondary); font-size: 0.875rem; margin: 1rem 0; }
.footer-contact a { color: var(--accent-green); }
.footer-copy { margin-top: 2rem; border-top: 1px solid rgba(255,255,255,0.05); padding-top: 1rem; font-size: 0.8125rem; color: var(--text-secondary); }

/* Buttons */
.btn { display: inline-flex; align-items: center; justify-content: center; font-family: inherit; font-weight: 600; font-size: 1rem; padding: 0.625rem 1.5rem; border: none; border-radius: 999px; cursor: pointer; background: var(--accent-green); color: #0D1B2A; transition: all 0.25s; }
.btn:hover, .btn:focus-visible { background: var(--accent-gold); color: #0D1B2A; }
.btn-outline { background: transparent; border: 2px solid var(--accent-green); color: var(--accent-green); }
.btn-outline:hover { background: var(--accent-green); color: #0D1B2A; }

/* Cards */
.card { background: var(--bg-card); border-radius: var(--border-radius); padding: 1.5rem; border: 1px solid rgba(0,255,135,0.08); }
.data-val { font-family: 'JetBrains Mono', monospace; color: var(--accent-green); font-weight: 700; font-size: 1.2em; }

/* Tab system */
.tabs { display: flex; gap: 0.5rem; flex-wrap: wrap; margin-bottom: 1rem; }
.tab-btn { background: transparent; border: 1px solid var(--accent-green); color: var(--text-secondary); padding: 0.5rem 1.25rem; border-radius: 999px; cursor: pointer; font-family: inherit; font-weight: 500; transition: all 0.2s; }
.tab-btn[aria-selected="true"] { background: var(--accent-green); color: #0D1B2A; }
.tab-panel:not([data-active]) { display: none; }

/* Return to top */
.scroll-top { position: fixed; right: 1.5rem; bottom: 2rem; width: 44px; height: 44px; border-radius: 50%; background: var(--accent-green); color: #0D1B2A; border: none; cursor: pointer; display: flex; align-items: center; justify-content: center; font-size: 1.25rem; opacity: 0; pointer-events: none; transition: opacity 0.3s; z-index: 400; box-shadow: 0 2px 8px rgba(0,0,0,0.3); }
.scroll-top[data-visible] { opacity: 1; pointer-events: auto; }

/* Responsive */
@media (max-width: 768px) {
  .nav-toggle { display: flex; }
  .site-nav { position: fixed; top: var(--header-height); left: 0; right: 0; background: #0D1B2A; border-bottom: 2px solid var(--accent-green); padding: 1rem; max-height: 0; overflow: hidden; transition: max-height 0.3s ease-out, padding 0.3s; }
  .site-nav[data-open] { max-height: 400px; padding: 1rem; }
  .nav-list { flex-direction: column; gap: 0.75rem; }
  .nav-link { display: block; padding: 0.5rem 0; border-bottom: 1px solid rgba(255,255,255,0.05); }
  .footer-links { flex-direction: column; gap: 0.75rem; }
  .footer-contact { flex-direction: column; gap: 0.5rem; }
}

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

/* Content rhythm */
.content-section + .content-narrow { margin-top: var(--spacing-section); }
.content-narrow + .content-section { margin-top: var(--spacing-section); }

/* placeholder image container */
.img-placeholder { background: var(--bg-card); border-radius: var(--border-radius); aspect-ratio: 16/9; display: flex; align-items: center; justify-content: center; color: var(--text-secondary); font-size: 0.875rem; }