/* ===== RESET ===== */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0;border:0;font:inherit;vertical-align:baseline}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%;text-size-adjust:100%}
body{min-height:100vh;line-height:1.6;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale}
img,picture,video,canvas,svg{display:block;max-width:100%}
input,button,textarea,select{font:inherit;color:inherit}
button{cursor:pointer;background:none;border:none}
a{color:inherit;text-decoration:none}
ul,ol{list-style:none}
table{border-collapse:collapse;border-spacing:0}
:focus-visible{outline:2px solid #1E88E5;outline-offset:2px}
@media(prefers-reduced-motion:reduce){*,*::before,*::after{transition-duration:0s!important;animation-duration:0s!important;scroll-behavior:auto!important}}

/* ===== CSS VARIABLES ===== */
:root{
  --bg-primary:#0D0D0D;
  --bg-secondary:#1A1A1A;
  --bg-accent:#262626;
  --brand-primary:#E53935;
  --brand-secondary:#1E88E5;
  --neutral-light:#B0BEC5;
  --neutral-dark:#F5F5F5;
  --border-subtle:#37474F;
  --text-primary:#FFFFFF;
  --text-secondary:#B0BEC5;
  --text-accent:#E53935;
  --shadow:0 4px 20px rgba(0,0,0,0.8);
  --font-heading:Oswald,Impact,sans-serif;
  --font-body:Roboto,"Noto Sans SC",sans-serif;
  --font-mono:"Fira Code",monospace;
  --space-unit:8px;
  --container-max:1280px;
  --header-z:1000;
  --transition-fast:0.2s ease;
  --transition-smooth:0.35s cubic-bezier(0.4,0,0.2,1);
}

/* ===== TYPOGRAPHY ===== */
body{font-family:var(--font-body);font-size:1rem;font-weight:400;color:var(--text-primary);background:var(--bg-primary);line-height:1.6}
h1,h2,h3,h4,h5,h6{font-family:var(--font-heading);font-weight:700;line-height:1.2;letter-spacing:0.02em}
h1{font-size:3.5rem}
h2{font-size:2.5rem}
h3{font-size:1.75rem}
small,.small{font-size:0.875rem}
caption,.caption{font-size:0.75rem;color:var(--text-secondary);letter-spacing:0.04em}
code,pre,.mono{font-family:var(--font-mono)}
.text-secondary{color:var(--text-secondary)}
.text-accent{color:var(--text-accent)}

/* ===== SKIP LINK ===== */
.skip-link{
  position:fixed;top:-100%;left:16px;z-index:2000;
  padding:12px 24px;background:var(--brand-primary);color:var(--text-primary);
  font-weight:700;font-size:0.875rem;border-radius:4px;
  transition:top var(--transition-smooth);
}
.skip-link:focus{top:16px}

/* ===== HEADER ===== */
.site-header{
  position:fixed;top:0;left:0;width:100%;z-index:var(--header-z);
  padding:16px 24px;
  background:rgba(13,13,13,0.88);
  backdrop-filter:blur(12px);
  -webkit-backdrop-filter:blur(12px);
  border-bottom:1px solid var(--border-subtle);
}
.header-inner{
  max-width:var(--container-max);margin:0 auto;
  display:flex;align-items:center;justify-content:space-between;
  gap:16px;
}
.site-logo{
  display:flex;align-items:baseline;gap:2px;
  font-family:var(--font-heading);font-weight:700;font-size:1.5rem;
  color:var(--text-primary);flex-shrink:0;
  transition:color var(--transition-fast);
}
.site-logo:hover{color:var(--brand-primary)}
.logo-mono{font-family:var(--font-mono);font-weight:700;letter-spacing:-0.02em}
.logo-dot{color:var(--brand-primary);font-weight:700}
.logo-cn{font-family:var(--font-heading);font-weight:400;letter-spacing:0.06em}

/* ===== NAVIGATION ===== */
.site-nav{flex:1;display:flex;justify-content:center}
.nav-list{display:flex;align-items:center;gap:4px}
.nav-link{
  display:block;padding:8px 16px;
  font-family:var(--font-body);font-size:0.875rem;font-weight:500;
  color:var(--text-secondary);letter-spacing:0.03em;
  border-bottom:2px solid transparent;
  transition:color var(--transition-fast),border-color var(--transition-fast),background var(--transition-fast);
  white-space:nowrap;
}
.nav-link:hover,.nav-link:focus-visible{color:var(--text-primary);border-bottom-color:var(--brand-primary)}
.nav-link[aria-current="page"]{color:var(--text-primary);border-bottom-color:var(--brand-primary);font-weight:700}

/* ===== NAV CTA ===== */
.nav-cta{
  display:inline-flex;align-items:center;gap:8px;
  padding:10px 20px;
  font-family:var(--font-heading);font-size:0.875rem;font-weight:700;
  color:var(--text-primary);background:var(--brand-primary);
  border:1px solid var(--brand-primary);
  transition:background var(--transition-fast),color var(--transition-fast),box-shadow var(--transition-fast);
  flex-shrink:0;
}
.nav-cta:hover,.nav-cta:focus-visible{
  background:transparent;color:var(--brand-primary);
  box-shadow:inset 0 0 0 1px var(--brand-primary);
}

/* ===== NAV TOGGLE (mobile) ===== */
.nav-toggle{
  display:none;flex-direction:column;justify-content:center;align-items:center;
  width:44px;height:44px;gap:5px;
  background:transparent;border:1px solid var(--border-subtle);
  cursor:pointer;flex-shrink:0;
}
.nav-toggle span{
  display:block;width:22px;height:2px;background:var(--text-primary);
  transition:transform var(--transition-smooth),opacity var(--transition-smooth);
  border-radius:1px;
}
.nav-toggle[aria-expanded="true"] span:nth-child(1){transform:translateY(7px) rotate(45deg)}
.nav-toggle[aria-expanded="true"] span:nth-child(2){opacity:0}
.nav-toggle[aria-expanded="true"] span:nth-child(3){transform:translateY(-7px) rotate(-45deg)}

/* ===== FOOTER ===== */
.site-footer{
  background:var(--bg-secondary);
  border-top:1px solid var(--border-subtle);
  padding:64px 24px 32px;
  margin-top:80px;
}
.footer-inner{
  max-width:var(--container-max);margin:0 auto;
  display:grid;grid-template-columns:1fr 1fr 1fr 1fr;
  gap:40px 32px;
}
.footer-brand{display:flex;flex-direction:column;gap:12px}
.footer-logo{display:flex;align-items:baseline;gap:2px;font-family:var(--font-heading);font-weight:700;font-size:1.25rem;color:var(--text-primary)}
.footer-logo .logo-mono{font-family:var(--font-mono);font-weight:700}
.footer-logo .logo-dot{color:var(--brand-primary)}
.footer-logo .logo-cn{font-weight:400}
.footer-tagline{font-size:0.875rem;color:var(--text-secondary);line-height:1.5;max-width:220px}
.footer-links{display:flex;flex-direction:column;gap:12px}
.footer-links-title,.footer-contact-title{font-family:var(--font-heading);font-size:0.75rem;font-weight:700;color:var(--brand-primary);letter-spacing:0.08em;text-transform:uppercase;margin-bottom:4px}
.footer-link{font-size:0.875rem;color:var(--text-secondary);transition:color var(--transition-fast)}
.footer-link:hover,.footer-link:focus-visible{color:var(--brand-primary)}
.footer-contact{display:flex;flex-direction:column;gap:8px}
.footer-contact-item{font-size:0.8125rem;color:var(--text-secondary);line-height:1.5}
.footer-copyright{grid-column:1/-1;display:flex;flex-direction:column;gap:8px;padding-top:24px;border-top:1px solid var(--border-subtle);margin-top:16px}
.footer-copyright span{font-size:0.75rem;color:var(--text-secondary);letter-spacing:0.02em}
.footer-trust{font-size:0.6875rem;color:var(--neutral-light);line-height:1.6;max-width:720px}

/* ===== SCROLL PROGRESS ===== */
.scroll-progress{
  position:fixed;top:0;left:0;width:100%;height:3px;z-index:calc(var(--header-z)+100);
  background:transparent;pointer-events:none;
}
.scroll-progress::after{
  content:'';display:block;width:0%;height:100%;
  background:var(--brand-primary);
  transition:width 0.1s linear;
}

/* ===== BUTTONS ===== */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  padding:12px 28px;font-family:var(--font-heading);font-size:0.875rem;font-weight:700;
  letter-spacing:0.04em;border:1px solid transparent;
  transition:all var(--transition-fast);cursor:pointer;
}
.btn-primary{background:var(--brand-primary);color:var(--text-primary);border-color:var(--brand-primary)}
.btn-primary:hover,.btn-primary:focus-visible{background:transparent;color:var(--brand-primary)}
.btn-outline{background:transparent;color:var(--brand-primary);border-color:var(--brand-primary)}
.btn-outline:hover,.btn-outline:focus-visible{background:var(--brand-primary);color:var(--text-primary)}

/* ===== CONTAINERS & GRID ===== */
.container{max-width:var(--container-max);margin:0 auto;padding:0 24px}
.section{padding:80px 0}
.section-sm{padding:48px 0}
.grid-2{display:grid;grid-template-columns:1fr 1fr;gap:32px}
.grid-3{display:grid;grid-template-columns:1fr 1fr 1fr;gap:28px}
.grid-4{display:grid;grid-template-columns:1fr 1fr 1fr 1fr;gap:24px}
.img-frame{
  background:var(--bg-accent);border:1px solid var(--border-subtle);
  aspect-ratio:16/9;display:flex;align-items:center;justify-content:center;
  color:var(--text-secondary);font-size:0.75rem;overflow:hidden;
}

/* ===== BREADCRUMB ===== */
.breadcrumb{display:flex;flex-wrap:wrap;gap:8px;padding:16px 0;font-size:0.8125rem;color:var(--text-secondary)}
.breadcrumb a{color:var(--text-secondary);transition:color var(--transition-fast)}
.breadcrumb a:hover{color:var(--brand-primary)}
.breadcrumb span{color:var(--neutral-light)}

/* ===== RESPONSIVE ===== */
@media(max-width:1024px){
  .footer-inner{grid-template-columns:1fr 1fr;gap:32px}
  .footer-copyright{grid-column:1/-1}
}
@media(max-width:768px){
  .site-header{padding:12px 16px}
  .header-inner{gap:12px}
  .nav-toggle{display:flex}
  .site-nav{
    position:absolute;top:100%;left:0;width:100%;
    background:rgba(13,13,13,0.96);backdrop-filter:blur(12px);-webkit-backdrop-filter:blur(12px);
    border-bottom:1px solid var(--border-subtle);
    max-height:0;overflow:hidden;opacity:0;
    transition:max-height var(--transition-smooth),opacity var(--transition-smooth);
    padding:0 16px;
  }
  .site-nav[data-open]{
    max-height:480px;opacity:1;
  }
  .nav-list{flex-direction:column;align-items:stretch;gap:0;padding:8px 0}
  .nav-link{padding:14px 12px;border-bottom:1px solid var(--border-subtle);font-size:1rem}
  .nav-link[aria-current="page"]{border-bottom-color:var(--brand-primary);background:rgba(229,57,53,0.08)}
  .nav-cta{margin-left:auto;padding:8px 16px;font-size:0.75rem}
  .header-inner{flex-wrap:nowrap}
  .site-logo{font-size:1.25rem}
  .container{padding:0 16px}
  .section{padding:48px 0}
  .section-sm{padding:32px 0}
  h1{font-size:2.25rem}
  h2{font-size:1.75rem}
  h3{font-size:1.375rem}
  .grid-2,.grid-3,.grid-4{grid-template-columns:1fr;gap:24px}
  .footer-inner{grid-template-columns:1fr;gap:32px;text-align:left}
  .footer-tagline{max-width:100%}
  .footer-copyright{padding-top:16px;margin-top:8px}
}
@media(min-width:769px){
  .site-nav{position:static;max-height:none!important;opacity:1!important;background:none;border:none;padding:0}
  .nav-list{flex-direction:row}
  .nav-link{padding:8px 16px}
}
@media(max-width:480px){
  .site-logo{font-size:1.1rem}
  .logo-mono{font-size:1rem}
  .nav-cta{padding:6px 12px;font-size:0.75rem}
}