/* ---------- Reset ---------- */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;scroll-padding-top:5rem}
body{font-family:'STKaiti','KaiTi','SimSun','Noto Serif SC',serif;background:#F5F8F6;color:#1A2E28;line-height:1.7;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale}
:focus-visible{outline:3px solid #FF8C42;outline-offset:2px}
/* ---------- CSS Custom Properties ---------- */
:root{
  --primary:#4B9B82;
  --secondary:#B8D4D0;
  --accent:#FF8C42;
  --bg-light:#F5F8F6;
  --bg-dark:#2A4D45;
  --text-primary:#1A2E28;
  --text-secondary:#5B7A70;
  --glass:rgba(255,255,255,0.6);
  --border:#D0E2DB;
  --header-height:5rem;
  --max-width:1200px;
  --font-heading:'STKaiti','KaiTi','SimSun','Noto Serif SC',serif;
  --font-body:-apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, 'Noto Sans SC', sans-serif;
  --transition:0.3s ease
}
/* ---------- Skip Link ---------- */
.skip-link{position:absolute;top:-100px;left:1rem;padding:0.5rem 1rem;background:#4B9B82;color:#fff;z-index:1000;transition:top 0.3s;border-radius:0 0 4px 4px;font-family:var(--font-body)}
.skip-link:focus{top:0}
/* ---------- Reading Progress ---------- */
#reading-progress{position:fixed;top:0;left:0;height:4px;background:linear-gradient(90deg,#4B9B82,#FF8C42);width:0%;z-index:1001;transition:width 0.1s linear}@media (prefers-reduced-motion:reduce){#reading-progress{display:none}}
/* ---------- Header ---------- */
.site-header{position:sticky;top:0;left:0;right:0;height:var(--header-height);background:var(--glass);backdrop-filter:blur(12px);-webkit-backdrop-filter:blur(12px);border-bottom:1px solid var(--border);z-index:999}
.header-inner{display:flex;align-items:center;justify-content:space-between;max-width:var(--max-width);margin:0 auto;padding:0 1.5rem;height:100%}
.site-logo{font-family:var(--font-heading);font-weight:bold;font-size:1.8rem;color:var(--bg-dark);text-decoration:none;letter-spacing:.1em}
.site-logo:hover{color:var(--primary)}
/* Navigation */
.nav-toggle{display:none;background:none;border:none;cursor:pointer;padding:.5rem;flex-direction:column;gap:5px;width:2rem;height:2rem;justify-content:center;align-items:center}@media (prefers-reduced-motion:reduce){.nav-toggle{transition:none}}
.nav-toggle span{display:block;width:1.5rem;height:2px;background:var(--bg-dark);border-radius:2px;transition:var(--transition)}@media (prefers-reduced-motion:reduce){.nav-toggle span{transition:none}}
.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)}
.nav ul{list-style:none;display:flex;gap:2rem;margin:0;padding:0}
.nav a{font-family:var(--font-body);font-size:1rem;color:var(--text-secondary);text-decoration:none;padding:.3rem 0;border-bottom:2px solid transparent;transition:var(--transition)}@media (prefers-reduced-motion:reduce){.nav a{transition:none}}
.nav a:hover,.nav a[aria-current="page"]{color:var(--primary);border-bottom-color:var(--accent)}
/* Mobile */
@media (max-width:768px){
  .nav-toggle{display:flex}
  .nav{position:fixed;top:var(--header-height);left:0;right:0;background:var(--glass);backdrop-filter:blur(20px);-webkit-backdrop-filter:blur(20px);padding:1rem 2rem;transform:translateY(-100%);opacity:0;transition:transform 0.3s ease,opacity 0.3s ease;border-bottom:1px solid var(--border);pointer-events:none}
  @media (prefers-reduced-motion:reduce){.nav{transition:none}}
  .nav[data-open]{transform:translateY(0);opacity:1;pointer-events:all}
  .nav ul{flex-direction:column;gap:1rem}
  .nav a{font-size:1.2rem;padding:.5rem 0}
}
/* ---------- Footer ---------- */
.site-footer{background:var(--bg-dark);color:#fff;padding:3rem 1.5rem 1rem;font-family:var(--font-body)}
.footer-inner{max-width:var(--max-width);margin:0 auto;display:grid;grid-template-columns:1fr 1fr 1fr;gap:2.5rem}
.footer-brand .site-logo{color:#fff;font-size:1.5rem;display:inline-block;margin-bottom:.5rem}
.footer-tagline{color:var(--secondary);font-size:0.95rem;line-height:1.6;max-width:20em}
.footer-links h3,.footer-contact h3{font-family:var(--font-heading);font-size:1.1rem;margin-bottom:1rem;color:var(--accent)}
.footer-links ul{list-style:none;padding:0}
.footer-links li{margin-bottom:0.5rem}
.footer-links a,.footer-contact a{color:var(--secondary);text-decoration:none;transition:color 0.2s}
.footer-links a:hover,.footer-contact a:hover{color:var(--accent)}
.footer-contact p{margin-bottom:0.3rem;font-size:0.95rem}
.footer-bottom{border-top:1px solid var(--border);margin-top:2rem;padding-top:1rem;text-align:center;font-size:0.85rem;color:var(--secondary)}
@media (max-width:768px){
  .footer-inner{grid-template-columns:1fr;gap:1.5rem}
  .footer-brand .site-logo{font-size:1.3rem}
}
/* ---------- Common Components ---------- */
.content-section{max-width:var(--max-width);margin:0 auto;padding:4rem 1.5rem}
.btn{display:inline-block;padding:0.75rem 1.8rem;border:none;border-radius:4px;font-family:var(--font-body);font-size:1rem;font-weight:600;cursor:pointer;text-decoration:none;transition:background 0.2s,transform 0.2s}@media (prefers-reduced-motion:reduce){.btn{transition:none}}
.btn-primary{background:var(--primary);color:#fff}
.btn-primary:hover{background:#3e7e68;transform:translateY(-1px)}
.btn-secondary{background:var(--secondary);color:var(--text-primary)}
.btn-secondary:hover{background:#a8c4be}
.btn-accent{background:var(--accent);color:#fff}
.btn-accent:hover{background:#e67830}
.card{background:var(--glass);backdrop-filter:blur(8px);-webkit-backdrop-filter:blur(8px);border:1px solid var(--border);border-radius:8px;padding:1.5rem;box-shadow:0 4px 12px rgba(0,0,0,0.05);transition:box-shadow 0.3s,transform 0.3s}@media (prefers-reduced-motion:reduce){.card{transition:none}}
.card:hover{box-shadow:0 6px 20px rgba(75,155,130,0.15);transform:translateY(-2px)}
.glass{background:var(--glass);backdrop-filter:blur(12px);-webkit-backdrop-filter:blur(12px)}
.grid{display:grid;gap:2rem;grid-template-columns:repeat(auto-fit,minmax(280px,1fr))}
.data-highlight{color:var(--accent);font-weight:bold;font-size:1.2em}
.image-placeholder{background:linear-gradient(135deg,var(--secondary) 0%,var(--primary) 100%);border-radius:8px;min-height:200px;display:flex;align-items:center;justify-content:center;color:#fff;font-family:var(--font-body);font-size:0.9rem;padding:1rem}
/* ---------- Responsive ---------- */
html{font-size:16px}@media (max-width:768px){html{font-size:15px}}@media (max-width:480px){html{font-size:14px}}
body{font-size:1rem;color:var(--text-primary)}
h1,h2,h3,h4,h5,h6{font-family:var(--font-heading);font-weight:bold;line-height:1.3;margin-bottom:0.75em;color:var(--text-primary)}
h1{font-size:2.5rem}h2{font-size:2rem}h3{font-size:1.5rem}h4{font-size:1.25rem}
p{font-family:var(--font-body);margin-bottom:1.2em;color:var(--text-secondary)}
a{color:var(--primary);transition:color 0.2s}
a:hover{color:var(--accent)}
/* ---------- Utility ---------- */
.text-accent{color:var(--accent)}
.text-primary{color:var(--primary)}
.bg-light{background:var(--bg-light)}
.bg-dark{background:var(--bg-dark);color:#fff}
.mt-1{margin-top:1rem}.mb-1{margin-bottom:1rem}.p-2{padding:2rem}