/* ===== RESET ===== */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0;border:0;font:inherit;vertical-align:baseline}
html{scroll-behavior:smooth;font-size:16px;-webkit-text-size-adjust:100%}
body{min-height:100vh;line-height:1.6;background-color:#100520;color:#E5D9F2;font-family:'Helvetica Neue',Arial,'PingFang SC','Microsoft YaHei',sans-serif;overflow-x:hidden}
img,svg,video,canvas{display:block;max-width:100%;height:auto}
ul,ol{list-style:none}
a{color:inherit;text-decoration:none}
button{cursor:pointer;background:none;color:inherit;font:inherit}
:focus-visible{outline:2px solid #D4AF37;outline-offset:2px;border-radius:2px}
@media(prefers-reduced-motion:reduce){*,*::before,*::after{animation-duration:0.01ms!important;animation-iteration-count:1!important;transition-duration:0.01ms!important;scroll-behavior:auto!important}}

/* ===== CSS VARIABLES ===== */
:root{
  --color-primary:#2B0F4C;
  --color-accent:#D4AF37;
  --color-secondary:#4A1C74;
  --color-dark:#100520;
  --color-light:#E5D9F2;
  --color-highlight:#C0392B;
  --gradient-primary:linear-gradient(135deg,#2B0F4C,#4A1C74);
  --gradient-gold:linear-gradient(135deg,#D4AF37,#F1C40F);
  --font-heading:'Helvetica Neue',Arial,'PingFang SC','Microsoft YaHei',sans-serif;
  --font-body:'Helvetica Neue',Arial,'PingFang SC','Microsoft YaHei',sans-serif;
  --font-mono:'Courier New',Consolas,monospace;
  --header-height:64px;
  --max-width:1200px;
  --transition:0.3s ease;
  --shadow-glow:0 0 30px rgba(212,175,55,0.15);
}

/* ===== TYPOGRAPHY ===== */
h1,h2,h3,h4,h5,h6{font-family:var(--font-heading);font-weight:800;font-style:italic;letter-spacing:0.02em;line-height:1.2;color:#E5D9F2}
h1{font-size:clamp(2.2rem,6vw,4.5rem)}
h2{font-size:clamp(1.8rem,4vw,3.2rem)}
h3{font-size:clamp(1.3rem,2.5vw,2rem)}
h4{font-size:clamp(1.1rem,1.8vw,1.5rem)}
p,li,label{font-family:var(--font-body);font-weight:400;font-size:1rem;line-height:1.7;color:#C4B8D6}
small,.text-small{font-size:0.85rem;color:#9B8DB0}
.mono{font-family:var(--font-mono);letter-spacing:0.01em}

/* ===== SKIP LINK ===== */
.skip-link{position:fixed;top:-100px;left:16px;z-index:10000;padding:12px 24px;background:#D4AF37;color:#100520;font-weight:700;border-radius:0 0 6px 6px;transition:top 0.3s ease}
.skip-link:focus{top:0}

/* ===== HEADER ===== */
.site-header{
  position:fixed;top:0;left:0;width:100%;z-index:9000;
  height:var(--header-height);
  background:transparent;
  transition:background 0.4s ease,box-shadow 0.4s ease;
  padding:0 24px;
}
.site-header.header--solid{
  background:rgba(16,5,32,0.95);
  box-shadow:0 2px 30px rgba(0,0,0,0.6);
  backdrop-filter:blur(12px);
  -webkit-backdrop-filter:blur(12px);
}
.header-inner{
  max-width:var(--max-width);margin:0 auto;
  display:flex;align-items:center;justify-content:space-between;
  height:100%;gap:16px;
}

/* Brand */
.header-brand{flex-shrink:0}
.brand-link{display:flex;align-items:center;gap:8px}
.brand-icon{font-size:1.6rem;color:#D4AF37;line-height:1;text-shadow:0 0 12px rgba(212,175,55,0.3)}
.brand-name{font-family:var(--font-heading);font-weight:800;font-style:italic;font-size:1.3rem;color:#E5D9F2;letter-spacing:0.04em}
.header--solid .brand-name{color:#E5D9F2}

/* Navigation */
.header-nav{flex:1;display:flex;justify-content:center}
.nav-list{display:flex;align-items:center;gap:8px}
.nav-list li a{
  display:block;padding:8px 16px;font-size:0.9rem;font-weight:500;
  color:rgba(229,217,242,0.8);border-radius:4px;transition:color 0.25s,background 0.25s;
  white-space:nowrap;
}
.nav-list li a:hover,.nav-list li a:focus-visible{color:#D4AF37;background:rgba(212,175,55,0.08)}
.nav-list li a[aria-current="page"]{color:#D4AF37;background:rgba(212,175,55,0.12);font-weight:700}

/* CTA Button */
.header-cta{
  flex-shrink:0;padding:10px 20px;border-radius:6px;
  background:var(--gradient-gold);color:#100520;
  font-weight:700;font-size:0.85rem;letter-spacing:0.02em;
  transition:transform 0.3s,box-shadow 0.3s;white-space:nowrap;
}
.header-cta:hover,.header-cta:focus-visible{transform:translateY(-2px);box-shadow:0 6px 24px rgba(212,175,55,0.35)}

/* Nav Toggle (mobile) */
.nav-toggle{display:none;flex-direction:column;justify-content:center;align-items:center;width:40px;height:40px;gap:5px;border-radius:4px;transition:background 0.25s}
.nav-toggle:hover{background:rgba(212,175,55,0.1)}
.nav-toggle-bar{display:block;width:22px;height:2px;background:#E5D9F2;border-radius:2px;transition:transform 0.35s,opacity 0.35s}
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(1){transform:translateY(7px) rotate(45deg)}
.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:translateY(-7px) rotate(-45deg)}

/* ===== FOOTER ===== */
.site-footer{
  background:#100520;
  border-top:1px solid rgba(212,175,55,0.12);
  padding:60px 24px 32px;
  margin-top:80px;
}
.footer-inner{
  max-width:var(--max-width);margin:0 auto;
  display:grid;grid-template-columns:2fr 1fr 1.5fr 1.5fr;gap:40px;
}
.footer-section{}
.footer-brand-area .brand-icon{font-size:2rem;color:#D4AF37;margin-bottom:4px}
.footer-brand-area .brand-name{font-family:var(--font-heading);font-weight:800;font-style:italic;font-size:1.5rem;color:#E5D9F2;display:block;margin-bottom:6px}
.footer-tagline{font-size:0.9rem;color:#9B8DB0;margin-top:4px}
.footer-heading{font-family:var(--font-heading);font-weight:700;font-style:italic;font-size:1rem;color:#D4AF37;margin-bottom:16px;letter-spacing:0.04em}
.footer-link-list{display:flex;flex-direction:column;gap:10px}
.footer-link-list a{color:#C4B8D6;font-size:0.9rem;transition:color 0.25s;display:inline-flex;align-items:center;gap:6px}
.footer-link-list a:hover,.footer-link-list a:focus-visible{color:#D4AF37}
.footer-link-list a::before{content:"›";color:#D4AF37;font-weight:700;font-size:1.1rem}
.footer-contact-item{font-size:0.9rem;color:#C4B8D6;margin-bottom:6px}
.footer-contact-item a{color:#D4AF37;transition:color 0.25s}
.footer-contact-item a:hover{color:#F1C40F}
.footer-icp{font-size:0.8rem;color:#6A5C7A;margin-bottom:8px}
.footer-statement{font-size:0.8rem;color:#6A5C7A;line-height:1.6;max-width:320px}

/* ===== PROGRESS BAR ===== */
.progress-bar{position:fixed;top:0;left:0;width:0;height:3px;z-index:9999;background:var(--gradient-gold);transition:width 0.1s linear;pointer-events:none}

/* ===== BACK TO TOP ===== */
.back-to-top{
  position:fixed;bottom:32px;right:32px;z-index:8000;
  width:48px;height:48px;border-radius:50%;
  background:var(--gradient-gold);color:#100520;
  display:flex;align-items:center;justify-content:center;
  font-size:1.4rem;font-weight:700;
  opacity:0;transform:translateY(20px);pointer-events:none;
  transition:opacity 0.35s,transform 0.35s,box-shadow 0.3s;
  box-shadow:0 4px 20px rgba(212,175,55,0.25);
}
.back-to-top.visible{opacity:1;transform:translateY(0);pointer-events:auto}
.back-to-top:hover,.back-to-top:focus-visible{box-shadow:0 6px 32px rgba(212,175,55,0.45);transform:translateY(-3px)}

/* ===== GENERIC BUTTONS ===== */
.btn{display:inline-flex;align-items:center;justify-content:center;padding:12px 28px;border-radius:6px;font-weight:600;font-size:0.95rem;transition:transform 0.3s,box-shadow 0.3s,background 0.3s;gap:8px}
.btn-accent{background:var(--gradient-gold);color:#100520}
.btn-accent:hover,.btn-accent:focus-visible{transform:translateY(-2px);box-shadow:0 6px 24px rgba(212,175,55,0.35)}
.btn-outline{border:1.5px solid rgba(212,175,55,0.5);color:#D4AF37;background:transparent}
.btn-outline:hover,.btn-outline:focus-visible{border-color:#D4AF37;background:rgba(212,175,55,0.08);transform:translateY(-2px)}

/* ===== BREADCRUMB ===== */
.breadcrumb{display:flex;flex-wrap:wrap;align-items:center;gap:8px;padding:16px 0;font-size:0.85rem;color:#9B8DB0}
.breadcrumb a{color:#C4B8D6;transition:color 0.25s}
.breadcrumb a:hover{color:#D4AF37}
.breadcrumb .separator{color:#4A1C74;font-weight:300}
.breadcrumb .current{color:#D4AF37;font-weight:600}

/* ===== CONTENT CONTAINER ===== */
.content-container{max-width:var(--max-width);margin:0 auto;padding:0 24px;width:100%}

/* ===== GRID ===== */
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:24px}

/* ===== CARD ===== */
.card{background:var(--gradient-primary);border-radius:12px;padding:32px 28px;border:1px solid rgba(212,175,55,0.1);transition:transform 0.35s,box-shadow 0.35s;position:relative}
.card:hover{transform:translateY(-4px);box-shadow:0 12px 40px rgba(16,5,32,0.6),0 0 20px rgba(212,175,55,0.05)}
.card-accent{border-color:rgba(212,175,55,0.3);box-shadow:0 0 30px rgba(212,175,55,0.04)}

/* ===== CHAPTER NUMBERING ===== */
.chapter-number{font-family:var(--font-mono);font-size:4rem;font-weight:700;line-height:1;color:#D4AF37;opacity:0.6;margin-bottom:4px}
.chapter-number.highlight{color:#C0392B;opacity:0.8}
.chapter-title{font-family:var(--font-heading);font-weight:800;font-style:italic;font-size:1.8rem;color:#E5D9F2;margin-bottom:16px}

/* ===== TABS ===== */
.tabs{width:100%}
.tab-list{display:flex;gap:4px;border-bottom:1px solid rgba(212,175,55,0.15);padding-bottom:0;margin-bottom:24px;overflow-x:auto}
.tab-item{padding:12px 24px;font-weight:600;font-size:0.9rem;color:#9B8DB0;border-radius:6px 6px 0 0;transition:color 0.25s,background 0.25s;white-space:nowrap;cursor:pointer;background:transparent}
.tab-item:hover{color:#D4AF37;background:rgba(212,175,55,0.05)}
.tab-item[aria-selected="true"]{color:#D4AF37;background:rgba(212,175,55,0.1);border-bottom:2px solid #D4AF37}
.tab-panel{display:none;padding:8px 0}
.tab-panel[aria-hidden="false"]{display:block}

/* ===== RESPONSIVE ===== */
@media(max-width:1024px){
  .footer-inner{grid-template-columns:1fr 1fr;gap:32px}
  .header-nav{position:fixed;top:var(--header-height);right:0;width:300px;height:calc(100vh - var(--header-height));background:#100520;border-left:1px solid rgba(212,175,55,0.15);transform:translateX(100%);transition:transform 0.4s cubic-bezier(0.22,1,0.36,1);padding:24px 20px;overflow-y:auto}
  .header-nav[data-open]{transform:translateX(0)}
  .nav-list{flex-direction:column;align-items:stretch;gap:4px}
  .nav-list li a{padding:12px 16px;font-size:1rem}
  .nav-toggle{display:flex}
  .header-cta{padding:8px 16px;font-size:0.8rem}
}

@media(max-width:768px){
  :root{--header-height:56px}
  .site-header{padding:0 16px}
  .brand-name{font-size:1.1rem}
  .brand-icon{font-size:1.3rem}
  .header-cta{font-size:0.75rem;padding:6px 12px}
  .header-nav{width:100%;border-left:none;border-top:1px solid rgba(212,175,55,0.1)}
  .footer-inner{grid-template-columns:1fr;gap:28px}
  .footer-section{padding-bottom:16px;border-bottom:1px solid rgba(212,175,55,0.06)}
  .footer-section:last-child{border-bottom:none;padding-bottom:0}
  .back-to-top{bottom:20px;right:20px;width:42px;height:42px;font-size:1.2rem}
  .content-container{padding:0 16px}
  .card{padding:24px 20px}
  .chapter-number{font-size:3rem}
  .chapter-title{font-size:1.4rem}
}

@media(max-width:480px){
  .header-cta{display:none}
  .header-nav{width:100%}
  .brand-name{font-size:1rem}
}

/* ===== UTILITY ===== */
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}
.text-center{text-align:center}
.text-gold{color:#D4AF37}
.text-muted{color:#9B8DB0}
.mt-1{margin-top:8px}
.mt-2{margin-top:16px}
.mt-3{margin-top:24px}
.mt-4{margin-top:32px}
.mb-1{margin-bottom:8px}
.mb-2{margin-bottom:16px}
.mb-3{margin-bottom:24px}
.mb-4{margin-bottom:32px}
.p-1{padding:8px}
.p-2{padding:16px}
.p-3{padding:24px}
.p-4{padding:32px}