/* ===== Reset & Base ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body { min-height: 100vh; background: #0a0a0f; color: #e2e8f0; font-family: 'Noto Sans SC', 'Microsoft YaHei', 'PingFang SC', system-ui, -apple-system, sans-serif; line-height: 1.6; -webkit-font-smoothing: antialiased; }
img, picture, video, canvas, svg { display: block; max-width: 100%; }
input, button, textarea, select { font: inherit; color: inherit; }
a { color: #8b5cf6; text-decoration: none; transition: color 0.2s, box-shadow 0.2s; }
a:hover { color: #06b6d4; }
a:focus-visible { outline: 2px solid #f97316; outline-offset: 2px; border-radius: 2px; }
ul, ol { list-style: none; }
:focus-visible { outline: 2px solid #f97316; outline-offset: 2px; }
::selection { background: #8b5cf6; color: #fff; }

/* ===== CSS Variables ===== */
:root {
  --color-bg-primary: #0a0a0f;
  --color-bg-secondary: #1a1a2e;
  --color-bg-tertiary: #16213e;
  --color-brand-start: #8b5cf6;
  --color-brand-end: #06b6d4;
  --color-accent: #f97316;
  --color-text-primary: #e2e8f0;
  --color-text-secondary: #94a3b8;
  --color-error: #ef4444;
  --color-success: #10b981;
  --color-border: rgba(139, 92, 246, 0.3);
  --color-glow: rgba(139, 92, 246, 0.5);
  --font-heading: 'Orbitron', 'Arial Black', 'Impact', sans-serif;
  --font-body: 'Noto Sans SC', 'Microsoft YaHei', 'PingFang SC', system-ui, sans-serif;
  --font-mono: 'JetBrains Mono', 'Courier New', monospace;
  --nav-height: 60px;
  --header-full-height: 160px;
  --content-max-width: 1200px;
  --panel-padding: 2rem;
  --border-width: 1px;
  --transition-fast: 0.2s ease;
  --transition-smooth: 0.4s cubic-bezier(0.22, 1, 0.36, 1);
}
@media (prefers-reduced-motion: reduce) {
  :root { --transition-fast: 0s; --transition-smooth: 0s; }
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: 0s !important; transition-duration: 0s !important; }
}

/* ===== Skip Link ===== */
.skip-link { position: absolute; top: -100%; left: 1rem; padding: 0.5rem 1rem; background: #8b5cf6; color: #fff; z-index: 1000; border-radius: 0 0 4px 4px; font-family: var(--font-mono); font-size: 0.875rem; transition: top var(--transition-fast); }
.skip-link:focus { top: 0; }

/* ===== Scroll Progress ===== */
.scroll-progress { position: fixed; top: 0; left: 0; width: 100%; height: 3px; background: transparent; z-index: 999; pointer-events: none; }
.scroll-progress::after { content: ''; display: block; height: 100%; width: 0%; background: linear-gradient(90deg, var(--color-brand-start), var(--color-brand-end), var(--color-accent)); transition: width 0.1s linear; }
.scroll-progress[data-scroll-progress]::after { width: var(--scroll-pct, 0%); }

/* ===== Header ===== */
.site-header { position: relative; z-index: 100; background: var(--color-bg-primary); border-bottom: var(--border-width) solid var(--color-border); }
.header-inner { max-width: var(--content-max-width); margin: 0 auto; padding: 1rem var(--panel-padding); display: flex; flex-direction: column; align-items: center; gap: 0.75rem; }
.brand { display: flex; flex-direction: column; align-items: center; gap: 0.15rem; position: relative; padding: 0.5rem 1.5rem; border: var(--border-width) solid var(--color-border); background: var(--color-bg-secondary); box-shadow: 0 0 12px rgba(139,92,246,0.15), inset 0 0 12px rgba(139,92,246,0.05); }
.brand::before, .brand::after { content: ''; position: absolute; width: 8px; height: 8px; border-color: var(--color-brand-start); border-style: solid; }
.brand::before { top: -1px; left: -1px; border-width: 2px 0 0 2px; }
.brand::after { bottom: -1px; right: -1px; border-width: 0 2px 2px 0; }
.brand-name { font-family: var(--font-heading); font-size: clamp(1.5rem, 4vw, 2.4rem); font-weight: 900; letter-spacing: 4px; background: linear-gradient(135deg, var(--color-brand-start), var(--color-brand-end), var(--color-accent)); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; filter: drop-shadow(0 0 8px var(--color-glow)); text-transform: uppercase; }
.brand-tagline { font-family: var(--font-mono); font-size: clamp(0.65rem, 1.2vw, 0.8rem); color: var(--color-text-secondary); letter-spacing: 2px; text-transform: uppercase; }

/* ===== Navigation ===== */
.site-nav { width: 100%; }
.nav-list { display: flex; flex-wrap: wrap; justify-content: center; gap: 0.25rem; }
.nav-item { margin: 0; }
.nav-link { display: block; padding: 0.5rem 1.2rem; font-family: var(--font-mono); font-size: 0.8rem; font-weight: 500; letter-spacing: 1.5px; text-transform: uppercase; color: var(--color-text-secondary); border: var(--border-width) solid transparent; transition: color var(--transition-fast), border-color var(--transition-fast), box-shadow var(--transition-fast); position: relative; }
.nav-link:hover, .nav-link:focus-visible { color: var(--color-text-primary); border-color: var(--color-border); box-shadow: 0 0 8px rgba(139,92,246,0.2); }
.nav-link[aria-current="page"], .nav-link[aria-current="true"] { color: #fff; border-color: var(--color-brand-start); box-shadow: 0 0 12px rgba(139,92,246,0.3); background: rgba(139,92,246,0.08); }
.nav-link[aria-current="page"]::after { content: ''; position: absolute; bottom: -1px; left: 10%; width: 80%; height: 2px; background: linear-gradient(90deg, transparent, var(--color-brand-end), transparent); }

/* ===== Nav Toggle (Mobile) ===== */
.nav-toggle { display: none; flex-direction: column; justify-content: center; align-items: center; gap: 4px; width: 44px; height: 44px; background: transparent; border: var(--border-width) solid var(--color-border); cursor: pointer; padding: 8px; transition: border-color var(--transition-fast); }
.nav-toggle:hover { border-color: var(--color-brand-start); }
.nav-toggle:focus-visible { outline: 2px solid var(--color-accent); outline-offset: 2px; }
.nav-toggle-line { display: block; width: 22px; height: 2px; background: var(--color-text-secondary); transition: transform var(--transition-smooth), opacity var(--transition-smooth); }
.nav-toggle[aria-expanded="true"] .nav-toggle-line:nth-child(1) { transform: translateY(6px) rotate(45deg); background: var(--color-brand-start); }
.nav-toggle[aria-expanded="true"] .nav-toggle-line:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] .nav-toggle-line:nth-child(3) { transform: translateY(-6px) rotate(-45deg); background: var(--color-brand-start); }

/* ===== Footer ===== */
.site-footer { background: var(--color-bg-secondary); border-top: var(--border-width) solid var(--color-border); position: relative; }
.site-footer::before { content: ''; position: absolute; top: -1px; left: 0; width: 100%; height: 1px; background: linear-gradient(90deg, transparent, var(--color-brand-start), var(--color-brand-end), transparent); }
.footer-inner { max-width: var(--content-max-width); margin: 0 auto; padding: 2.5rem var(--panel-padding) 1.5rem; }
.footer-grid { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 2rem; align-items: start; }
.footer-brand { display: flex; flex-direction: column; gap: 0.25rem; }
.footer-brand-name { font-family: var(--font-heading); font-size: 1.2rem; font-weight: 700; letter-spacing: 2px; background: linear-gradient(135deg, var(--color-brand-start), var(--color-brand-end)); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; text-transform: uppercase; }
.footer-brand-tagline { font-family: var(--font-mono); font-size: 0.7rem; color: var(--color-text-secondary); letter-spacing: 1px; }
.footer-links { display: flex; flex-direction: column; gap: 0.5rem; }
.footer-link { font-family: var(--font-mono); font-size: 0.8rem; color: var(--color-text-secondary); letter-spacing: 1px; transition: color var(--transition-fast), padding-left var(--transition-fast); padding: 0.2rem 0; }
.footer-link:hover { color: var(--color-brand-end); padding-left: 4px; }
.footer-info { display: flex; flex-direction: column; gap: 0.4rem; font-size: 0.8rem; color: var(--color-text-secondary); line-height: 1.5; }
.footer-contact { font-family: var(--font-mono); font-size: 0.75rem; }
.footer-icp { font-size: 0.7rem; color: var(--color-text-secondary); opacity: 0.7; }
.footer-trust { font-size: 0.7rem; color: var(--color-text-secondary); opacity: 0.6; border-left: 2px solid var(--color-brand-start); padding-left: 0.75rem; margin-top: 0.25rem; }
.footer-copy { text-align: center; font-size: 0.7rem; color: var(--color-text-secondary); opacity: 0.5; margin-top: 2rem; padding-top: 1rem; border-top: var(--border-width) solid rgba(139,92,246,0.1); font-family: var(--font-mono); letter-spacing: 1px; }

/* ===== Panel (Shared Content Block) ===== */
.panel { background: var(--color-bg-secondary); border: var(--border-width) solid var(--color-border); padding: var(--panel-padding); position: relative; }
.panel::before { content: ''; position: absolute; top: -1px; left: 0; width: 100%; height: 1px; background: linear-gradient(90deg, transparent, var(--color-brand-start), transparent); opacity: 0.5; }
.panel.glow-border { box-shadow: 0 0 8px rgba(139,92,246,0.1), inset 0 0 8px rgba(139,92,246,0.05); }

/* ===== Button ===== */
.btn { display: inline-flex; align-items: center; justify-content: center; padding: 0.6rem 1.6rem; font-family: var(--font-mono); font-size: 0.8rem; font-weight: 600; letter-spacing: 1.5px; text-transform: uppercase; border: var(--border-width) solid var(--color-border); background: transparent; color: var(--color-text-primary); cursor: pointer; transition: all var(--transition-fast); position: relative; overflow: hidden; }
.btn:hover { border-color: var(--color-brand-start); box-shadow: 0 0 12px rgba(139,92,246,0.25); }
.btn:focus-visible { outline: 2px solid var(--color-accent); outline-offset: 2px; }
.btn-primary { background: linear-gradient(135deg, var(--color-brand-start), var(--color-brand-end)); border-color: transparent; color: #fff; box-shadow: 0 0 10px rgba(139,92,246,0.3); }
.btn-primary:hover { box-shadow: 0 0 20px rgba(139,92,246,0.5); border-color: transparent; color: #fff; }
.btn[data-btn] { position: relative; }
.btn[data-btn]::after { content: ''; position: absolute; inset: 0; background: rgba(255,255,255,0.1); opacity: 0; transition: opacity var(--transition-fast); }
.btn[data-btn]:active::after { opacity: 1; }

/* ===== Section Indicator ===== */
.section-indicator { position: fixed; left: 0; top: 50%; transform: translateY(-50%); z-index: 50; display: flex; flex-direction: column; gap: 0.5rem; padding: 0.5rem; background: rgba(10,10,15,0.8); border: var(--border-width) solid var(--color-border); border-left: none; }
.section-indicator[data-section-list] { display: flex; }
.section-dot { width: 8px; height: 8px; border: 1px solid var(--color-text-secondary); background: transparent; border-radius: 0; transition: all var(--transition-smooth); cursor: pointer; }
.section-dot.active { background: var(--color-brand-start); border-color: var(--color-brand-end); box-shadow: 0 0 6px var(--color-glow); width: 12px; height: 12px; }
.section-dot:hover { border-color: var(--color-accent); }

/* ===== Grid & Utilities ===== */
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 1.5rem; }
.grid-3 { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 1.5rem; }
.grid-4 { display: grid; grid-template-columns: 1fr 1fr 1fr 1fr; gap: 1rem; }
.text-mono { font-family: var(--font-mono); }
.text-gradient { background: linear-gradient(135deg, var(--color-brand-start), var(--color-brand-end)); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
.text-accent { color: var(--color-accent); }
.text-secondary { color: var(--color-text-secondary); }
.text-success { color: var(--color-success); }
.text-error { color: var(--color-error); }
.bg-tertiary { background: var(--color-bg-tertiary); }

/* ===== Responsive ===== */
@media (max-width: 900px) {
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .grid-3, .grid-4 { grid-template-columns: 1fr 1fr; }
  :root { --panel-padding: 1.25rem; }
}
@media (max-width: 640px) {
  .header-inner { flex-direction: row; flex-wrap: wrap; justify-content: space-between; padding: 0.75rem 1rem; }
  .brand { order: 1; flex: 1; border: none; background: transparent; padding: 0; box-shadow: none; align-items: flex-start; }
  .brand::before, .brand::after { display: none; }
  .brand-name { font-size: 1.2rem; letter-spacing: 2px; }
  .brand-tagline { font-size: 0.6rem; }
  .nav-toggle { display: flex; order: 2; }
  .site-nav { order: 3; width: 100%; display: none; }
  .site-nav[data-open] { display: block; }
  .nav-list { flex-direction: column; gap: 0; background: var(--color-bg-secondary); border: var(--border-width) solid var(--color-border); margin-top: 0.5rem; }
  .nav-link { padding: 0.75rem 1rem; border-bottom: var(--border-width) solid rgba(139,92,246,0.1); }
  .nav-link[aria-current="page"] { background: rgba(139,92,246,0.12); }
  .nav-link[aria-current="page"]::after { display: none; }
  .footer-grid { grid-template-columns: 1fr; gap: 1.5rem; }
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
  :root { --panel-padding: 1rem; }
  .footer-inner { padding: 1.5rem 1rem 1rem; }
  .section-indicator { display: none; }
}
@media (max-width: 400px) {
  .brand-name { font-size: 1rem; }
  .nav-link { font-size: 0.75rem; padding: 0.6rem 0.8rem; }
}