/* Reset */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body { min-height: 100vh; }

/* Variables */
:root {
  --primary: #00D4FF;
  --secondary: #FF2D55;
  --bg-dark: #0D1117;
  --bg-light: #1A1F26;
  --text-primary: #FFFFFF;
  --text-secondary: #B0B8C4;
  --accent-green: #00FFAA;
  --accent-purple: #7B2FFF;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  --font-mono: 'JetBrains Mono', 'SF Mono', 'Fira Code', 'Fira Mono', 'Roboto Mono', monospace;
  --header-height: 64px;
  --max-width: 1280px;
  --gap: 2rem;
  --radius: 0;
  --transition: 0.3s ease;
}

/* Typography */
body { font-family: var(--font-sans); color: var(--text-primary); background: var(--bg-dark); line-height: 1.6; -webkit-font-smoothing: antialiased; }
h1, h2, h3, h4 { font-weight: 800; letter-spacing: 0.05em; }
code, .mono { font-family: var(--font-mono); }

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

/* Header */
.header { position: fixed; top: 0; left: 0; width: 100%; height: var(--header-height); background: rgba(13, 17, 23, 0.85); backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px); z-index: 100; display: flex; align-items: center; justify-content: space-between; padding: 0 calc((100vw - var(--max-width)) / 2); padding-left: 1.5rem; padding-right: 1.5rem; border-bottom: 1px solid rgba(255,255,255,0.08); }
.header__logo { display: flex; align-items: center; text-decoration: none; color: var(--text-primary); }

/* Navigation */
.nav__list { list-style: none; display: flex; gap: 0.25rem; }
.nav__link { display: inline-block; padding: 0.5rem 1rem; color: var(--text-secondary); text-decoration: none; font-size: 0.875rem; font-weight: 500; letter-spacing: 0.02em; text-transform: uppercase; border-bottom: 2px solid transparent; transition: color var(--transition), border-color var(--transition); }
.nav__link:hover, .nav__link:focus-visible { color: var(--text-primary); }
.nav__link[aria-current="page"] { color: var(--primary); border-bottom-color: var(--primary); }

/* Nav toggle (mobile) */
.nav-toggle { display: none; background: transparent; border: none; cursor: pointer; padding: 0.25rem; width: 36px; height: 36px; flex-direction: column; justify-content: center; align-items: center; gap: 5px; }
.nav-toggle__bar { display: block; width: 24px; height: 2px; background: var(--text-primary); border-radius: 1px; transition: transform var(--transition), opacity var(--transition); }
[data-open] .nav-toggle__bar:nth-child(1) { transform: translateY(7px) rotate(45deg); }
[data-open] .nav-toggle__bar:nth-child(2) { opacity: 0; }
[data-open] .nav-toggle__bar:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* Mobile navigation */
@media (max-width: 768px) {
  .nav-toggle { display: flex; }
  .nav { position: absolute; top: var(--header-height); left: 0; width: 100%; background: rgba(13, 17, 23, 0.95); backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px); max-height: 0; overflow: hidden; transition: max-height var(--transition); }
  .nav[data-open] { max-height: 400px; }
  .nav__list { flex-direction: column; padding: 1rem; gap: 0; }
  .nav__link { padding: 0.75rem 1rem; border-bottom: none; border-left: 3px solid transparent; }
  .nav__link[aria-current="page"] { border-left-color: var(--primary); color: var(--primary); }
}

/* Footer */
.footer { background: var(--bg-light); border-top: 1px solid rgba(255,255,255,0.06); padding: 2.5rem 1.5rem; }
.footer__inner { max-width: var(--max-width); margin: 0 auto; display: flex; flex-direction: column; gap: 1.5rem; }
.footer__brand { display: flex; flex-direction: column; gap: 0.25rem; }
.footer__logo { font-size: 1.5rem; font-weight: 800; letter-spacing: 0.08em; background: linear-gradient(135deg, var(--primary), var(--accent-purple)); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
.footer__tagline { color: var(--text-secondary); font-size: 0.875rem; }
.footer__links { display: flex; flex-wrap: wrap; gap: 1.5rem; align-items: center; }
.footer__link { color: var(--text-secondary); text-decoration: none; font-size: 0.875rem; transition: color var(--transition); }
.footer__link:hover, .footer__link:focus-visible { color: var(--secondary); }
.footer__contact { color: var(--text-secondary); font-size: 0.875rem; }
.footer__meta { display: flex; flex-wrap: wrap; gap: 1rem; justify-content: space-between; align-items: center; border-top: 1px solid rgba(255,255,255,0.06); padding-top: 1rem; color: var(--text-secondary); font-size: 0.75rem; }
.footer__icp { order: 1; }
.footer__copyright { order: 2; }
@media (max-width: 768px) {
  .footer__links { flex-direction: column; align-items: flex-start; }
  .footer__meta { flex-direction: column; align-items: flex-start; gap: 0.5rem; }
}

/* Progress bar */
.progress-bar { position: fixed; top: 0; left: 0; width: 0; height: 3px; background: linear-gradient(90deg, var(--primary), var(--accent-purple)); z-index: 999; transition: width 0.1s linear; pointer-events: none; }

/* Shared utility */
.container { max-width: var(--max-width); margin: 0 auto; padding: 0 1.5rem; }
.main-content { padding-top: var(--header-height); }
button { font-family: inherit; cursor: pointer; }
a { color: inherit; }

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { transition-duration: 0s !important; animation-duration: 0s !important; }
  html { scroll-behavior: auto; }
  .progress-bar { display: none; }
}

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