:root{
  --bg:#f7f9fc;
  --bg-card:#ffffff;
  --bg-alt:#eef2f8;
  --text:#17202A;
  --text-body:#1F2937;
  --text-secondary:#334155;
  --text-muted:#4b5563;
  --heading:#0f172a;
  --brand:#1a2a6c;
  --brand-light:#2b3f8f;
  --brand-dark:#0d1a4a;
  --accent:#c0392b;
  --accent-hover:#a93226;
  --border:#d1d9e6;
  --link:#1a2a6c;
  --link-hover:#c0392b;
  --shadow:0 2px 12px rgba(15,23,42,.08);
  --shadow-hover:0 6px 24px rgba(15,23,42,.14);
  --nav-bg:rgba(255,255,255,.96);
  --nav-text:#17202A;
  --footer-bg:#0d1a4a;
  --footer-text:#dbe4f0;
  --footer-heading:#ffffff;
  --banner-overlay:rgba(13,26,74,.72);
  --banner-text:#ffffff;
  --tag-bg:#e8edf7;
  --tag-text:#1a2a6c;
  --btn-bg:#1a2a6c;
  --btn-text:#ffffff;
  --btn-hover:#0d1a4a;
  --faq-q:#0f172a;
  --faq-a:#1F2937;
  --input-bg:#ffffff;
  --input-text:#17202A;
  --input-border:#cbd5e1;
  --table-head:#1a2a6c;
  --table-head-text:#ffffff;
  --table-row-alt:#f1f5fb;
}
html[data-theme="dark"]{
  --bg:#0f172a;
  --bg-card:#1e293b;
  --bg-alt:#16213a;
  --text:#E5E7EB;
  --text-body:#E2E8F0;
  --text-secondary:#cbd5e1;
  --text-muted:#94a3b8;
  --heading:#F8FAFC;
  --brand:#4a6cf7;
  --brand-light:#6b8cff;
  --brand-dark:#3a5ce0;
  --accent:#f87171;
  --accent-hover:#fca5a5;
  --border:#334155;
  --link:#93c5fd;
  --link-hover:#fca5a5;
  --shadow:0 2px 12px rgba(0,0,0,.4);
  --shadow-hover:0 6px 24px rgba(0,0,0,.55);
  --nav-bg:rgba(15,23,42,.96);
  --nav-text:#E5E7EB;
  --footer-bg:#0a1124;
  --footer-text:#cbd5e1;
  --footer-heading:#F8FAFC;
  --banner-overlay:rgba(2,6,23,.78);
  --banner-text:#F8FAFC;
  --tag-bg:#1e3a5f;
  --tag-text:#bfdbfe;
  --btn-bg:#4a6cf7;
  --btn-text:#ffffff;
  --btn-hover:#3a5ce0;
  --faq-q:#F8FAFC;
  --faq-a:#E2E8F0;
  --input-bg:#1e293b;
  --input-text:#E5E7EB;
  --input-border:#475569;
  --table-head:#1e3a5f;
  --table-head-text:#F8FAFC;
  --table-row-alt:#16213a;
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei","微软雅黑",sans-serif;
  background:var(--bg);
  color:var(--text-body);
  line-height:1.8;
  font-size:16px;
  transition:background .3s,color .3s;
  -webkit-font-smoothing:antialiased;
}
h1,h2,h3,h4{color:var(--heading);line-height:1.4;font-weight:700}
h1{font-size:2rem;margin-bottom:1rem}
h2{font-size:1.6rem;margin:2rem 0 1rem;padding-bottom:.5rem;border-bottom:2px solid var(--border)}
h3{font-size:1.25rem;margin:1.5rem 0 .75rem;color:var(--brand)}
h4{font-size:1.05rem;margin:1rem 0 .5rem;color:var(--text-secondary)}
p{margin-bottom:1rem;color:var(--text-body)}
a{color:var(--link);text-decoration:none;transition:color .2s}
a:hover{color:var(--link-hover);text-decoration:underline}
ul,ol{margin:0 0 1rem 1.5rem;color:var(--text-body)}
li{margin-bottom:.4rem}
img,svg{max-width:100%;height:auto;display:block}
.container{max-width:1180px;margin:0 auto;padding:0 1.25rem}
.skip-link{position:absolute;left:-9999px;top:0;background:var(--btn-bg);color:var(--btn-text);padding:.5rem 1rem;z-index:10000}
.skip-link:focus{left:0}
/* ===== NAV ===== */
.nav-wrap{
  position:sticky;top:0;z-index:1000;
  background:var(--nav-bg);
  backdrop-filter:blur(12px);
  border-bottom:1px solid var(--border);
  transition:background .3s,border-color .3s;
}
.nav-inner{
  max-width:1180px;margin:0 auto;padding:0 1.25rem;
  display:flex;align-items:center;justify-content:space-between;
  height:64px;
}
.nav-logo{display:flex;align-items:center;gap:.6rem;font-weight:800;font-size:1.15rem;color:var(--heading)}
.nav-logo svg{width:36px;height:36px;flex-shrink:0}
.nav-logo span{color:var(--heading)}
.nav-logo em{font-style:normal;color:var(--brand);font-size:.75rem;font-weight:600;margin-left:.2rem}
.nav-menu{display:flex;align-items:center;gap:.25rem;list-style:none;margin:0}
.nav-menu a{
  display:block;padding:.5rem .85rem;border-radius:8px;
  color:var(--nav-text);font-size:.92rem;font-weight:500;
  transition:background .2s,color .2s;
}
.nav-menu a:hover,.nav-menu a:focus{background:var(--bg-alt);color:var(--brand);text-decoration:none}
.nav-actions{display:flex;align-items:center;gap:.5rem}
.theme-btn{
  width:40px;height:40px;border-radius:10px;border:1px solid var(--border);
  background:var(--bg-card);color:var(--text-body);cursor:pointer;
  display:flex;align-items:center;justify-content:center;
  transition:background .2s,color .2s,border-color .2s;
}
.theme-btn:hover{background:var(--bg-alt);color:var(--brand)}
.theme-btn svg{width:20px;height:20px}
.menu-toggle{
  display:none;width:40px;height:40px;border-radius:10px;border:1px solid var(--border);
  background:var(--bg-card);color:var(--text-body);cursor:pointer;
  align-items:center;justify-content:center;
}
.menu-toggle svg{width:22px;height:22px}
/* ===== SEARCH ===== */
.search-box{
  display:flex;align-items:center;gap:.4rem;
  background:var(--input-bg);border:1px solid var(--input-border);
  border-radius:10px;padding:.35rem .6rem;transition:border-color .2s;
}
.search-box:focus-within{border-color:var(--brand)}
.search-box input{
  border:none;outline:none;background:transparent;color:var(--input-text);
  font-size:.9rem;width:150px;font-family:inherit;
}
.search-box input::placeholder{color:var(--text-muted)}
.search-box button{
  border:none;background:transparent;color:var(--brand);cursor:pointer;
  display:flex;align-items:center;padding:0;
}
.search-box button svg{width:18px;height:18px}
/* ===== BANNER ===== */
.banner{
  position:relative;overflow:hidden;
  background:linear-gradient(135deg,var(--brand-dark) 0%,var(--brand) 50%,var(--brand-light) 100%);
  min-height:340px;display:flex;align-items:center;
}
.banner-slides{position:relative;width:100%;min-height:340px}
.banner-slide{
  position:absolute;inset:0;opacity:0;transition:opacity .8s ease;
  display:flex;align-items:center;justify-content:center;padding:3rem 1.25rem;
}
.banner-slide.active{opacity:1;position:relative}
.banner-content{max-width:820px;text-align:center;position:relative;z-index:2}
.banner-content h2{
  color:var(--banner-text);font-size:2rem;border:none;margin:0 0 1rem;
  text-shadow:0 2px 12px rgba(0,0,0,.5);
}
.banner-content p{
  color:#e8edf7;font-size:1.05rem;margin-bottom:1.5rem;
  text-shadow:0 1px 8px rgba(0,0,0,.5);
}
.banner-btns{display:flex;gap:1rem;justify-content:center;flex-wrap:wrap}
.btn{
  display:inline-block;padding:.7rem 1.6rem;border-radius:10px;
  font-weight:600;font-size:.95rem;cursor:pointer;border:2px solid transparent;
  transition:background .2s,color .2s,border-color .2s,transform .2s;
}
.btn-primary{background:var(--btn-bg);color:var(--btn-text);border-color:var(--btn-bg)}
.btn-primary:hover{background:var(--btn-hover);border-color:var(--btn-hover);color:var(--btn-text);text-decoration:none;transform:translateY(-2px)}
.btn-outline{background:transparent;color:var(--banner-text);border-color:var(--banner-text)}
.btn-outline:hover{background:rgba(255,255,255,.15);color:#ffffff;text-decoration:none;transform:translateY(-2px)}
.banner-dots{
  position:absolute;bottom:1.2rem;left:50%;transform:translateX(-50%);
  display:flex;gap:.5rem;z-index:5;
}
.banner-dots button{
  width:10px;height:10px;border-radius:50%;border:none;cursor:pointer;
  background:rgba(255,255,255,.5);transition:background .2s,transform .2s;
}
.banner-dots button.active{background:#ffffff;transform:scale(1.3)}
/* ===== BREADCRUMB ===== */
.breadcrumb{
  max-width:1180px;margin:0 auto;padding:1rem 1.25rem .5rem;
  font-size:.85rem;color:var(--text-muted);
}
.breadcrumb a{color:var(--link)}
.breadcrumb span{margin:0 .4rem;color:var(--text-muted)}
/* ===== SECTIONS ===== */
section{padding:2.5rem 0}
.section-alt{background:var(--bg-alt)}
.section-title{text-align:center;margin-bottom:2rem}
.section-title h2{border:none;display:inline-block;position:relative;padding-bottom:.6rem}
.section-title h2::after{
  content:"";position:absolute;bottom:0;left:50%;transform:translateX(-50%);
  width:60px;height:3px;background:var(--brand);border-radius:2px;
}
.section-title p{color:var(--text-secondary);max-width:680px;margin:.5rem auto 0}
.grid-2{display:grid;grid-template-columns:repeat(auto-fit,minmax(320px,1fr));gap:1.5rem}
.grid-3{display:grid;grid-template-columns:repeat(auto-fit,minmax(280px,1fr));gap:1.5rem}
.grid-4{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:1.25rem}
.card{
  background:var(--bg-card);border:1px solid var(--border);border-radius:14px;
  padding:1.5rem;box-shadow:var(--shadow);transition:box-shadow .25s,transform .25s;
}
.card:hover{box-shadow:var(--shadow-hover);transform:translateY(-4px)}
.card h3{margin-top:0}
.card p:last-child{margin-bottom:0}
.card-icon{
  width:48px;height:48px;border-radius:12px;background:var(--tag-bg);
  display:flex;align-items:center;justify-content:center;margin-bottom:1rem;
}
.card-icon svg{width:26px;height:26px}
/* ===== STATS ===== */
.stats{display:grid;grid-template-columns:repeat(auto-fit,minmax(160px,1fr));gap:1.5rem;text-align:center}
.stat-num{font-size:2.2rem;font-weight:800;color:var(--brand);line-height:1.2}
.stat-label{color:var(--text-secondary);font-size:.9rem;margin-top:.3rem}
/* ===== ARTICLES ===== */
.article-card{
  background:var(--bg-card);border:1px solid var(--border);border-radius:14px;
  overflow:hidden;box-shadow:var(--shadow);transition:box-shadow .25s,transform .25s;
  display:flex;flex-direction:column;
}
.article-card:hover{box-shadow:var(--shadow-hover);transform:translateY(-4px)}
.article-thumb{width:100%;height:160px;overflow:hidden}
.article-thumb svg{width:100%;height:100%;display:block}
.article-body{padding:1.25rem;flex:1;display:flex;flex-direction:column}
.article-meta{font-size:.8rem;color:var(--text-muted);margin-bottom:.5rem}
.article-body h3{font-size:1.05rem;margin:0 0 .5rem;color:var(--heading)}
.article-body p{font-size:.9rem;color:var(--text-body);flex:1}
.read-more{font-size:.88rem;font-weight:600;color:var(--link);margin-top:.5rem}
.read-more:hover{color:var(--link-hover)}
/* ===== FAQ ===== */
.faq-list{max-width:860px;margin:0 auto}
.faq-item{
  background:var(--bg-card);border:1px solid var(--border);border-radius:12px;
  margin-bottom:.75rem;overflow:hidden;
}
.faq-q{
  width:100%;text-align:left;padding:1.1rem 1.25rem;
  background:transparent;border:none;cursor:pointer;
  font-size:1rem;font-weight:600;color:var(--faq-q);
  display:flex;justify-content:space-between;align-items:center;gap:1rem;
  font-family:inherit;transition:background .2s;
}
.faq-q:hover{background:var(--bg-alt)}
.faq-q svg{width:20px;height:20px;flex-shrink:0;transition:transform .3s;color:var(--brand)}
.faq-item.open .faq-q svg{transform:rotate(180deg)}
.faq-a{
  max-height:0;overflow:hidden;transition:max-height .35s ease;
  padding:0 1.25rem;
}
.faq-item.open .faq-a{max-height:600px;padding-bottom:1.1rem}
.faq-a p{color:var(--faq-a);font-size:.93rem;margin-bottom:.5rem}
.faq-a p:last-child{margin-bottom:0}
/* ===== HOWTO ===== */
.howto-steps{counter-reset:step;max-width:860px;margin:0 auto}
.howto-step{
  position:relative;padding:1.25rem 1.25rem 1.25rem 4rem;
  background:var(--bg-card);border:1px solid var(--border);border-radius:12px;
  margin-bottom:1rem;
}
.howto-step::before{
  counter-increment:step;content:counter(step);
  position:absolute;left:1.1rem;top:1.25rem;
  width:36px;height:36px;border-radius:50%;
  background:var(--btn-bg);color:var(--btn-text);
  display:flex;align-items:center;justify-content:center;
  font-weight:700;font-size:.95rem;
}
.howto-step h4{margin:0 0 .4rem;color:var(--heading)}
.howto-step p{margin-bottom:0;font-size:.93rem}
/* ===== TABLE ===== */
.table-wrap{overflow-x:auto;margin:1.5rem 0}
table{width:100%;border-collapse:collapse;font-size:.92rem;min-width:600px}
th{
  background:var(--table-head);color:var(--table-head-text);
  padding:.75rem 1rem;text-align:left;font-weight:600;
}
td{padding:.7rem 1rem;border-bottom:1px solid var(--border);color:var(--text-body)}
tr:nth-child(even) td{background:var(--table-row-alt)}
/* ===== CONTACT ===== */
.contact-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));gap:1.5rem}
.contact-item{
  background:var(--bg-card);border:1px solid var(--border);border-radius:12px;
  padding:1.25rem;display:flex;gap:1rem;align-items:flex-start;
}
.contact-item svg{width:24px;height:24px;color:var(--brand);flex-shrink:0;margin-top:.2rem}
.contact-item h4{margin:0 0 .2rem;font-size:.95rem}
.contact-item p{margin:0;font-size:.88rem;color:var(--text-secondary)}
/* ===== FOOTER ===== */
footer{
  background:var(--footer-bg);color:var(--footer-text);
  padding:3rem 0 1.5rem;margin-top:2rem;
}
.footer-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:2rem;margin-bottom:2rem}
.footer-col h4{color:var(--footer-heading);font-size:1rem;margin-bottom:1rem}
.footer-col ul{list-style:none;margin:0;padding:0}
.footer-col li{margin-bottom:.5rem}
.footer-col a{color:var(--footer-text);font-size:.88rem}
.footer-col a:hover{color:#ffffff;text-decoration:underline}
.footer-col p{color:var(--footer-text);font-size:.88rem;margin-bottom:.5rem}
.footer-bottom{
  border-top:1px solid rgba(255,255,255,.15);padding-top:1.5rem;
  display:flex;flex-wrap:wrap;justify-content:space-between;gap:1rem;
  font-size:.82rem;color:var(--footer-text);
}
.footer-bottom a{color:var(--footer-text)}
.footer-bottom a:hover{color:#ffffff}
/* ===== BACK TO TOP ===== */
.back-top{
  position:fixed;right:1.5rem;bottom:1.5rem;z-index:999;
  width:46px;height:46px;border-radius:50%;border:none;cursor:pointer;
  background:var(--btn-bg);color:var(--btn-text);
  display:flex;align-items:center;justify-content:center;
  box-shadow:var(--shadow-hover);
  opacity:0;visibility:hidden;transition:opacity .3s,visibility .3s,background .2s;
}
.back-top.show{opacity:1;visibility:visible}
.back-top:hover{background:var(--btn-hover)}
.back-top svg{width:22px;height:22px}
/* ===== SCROLL ANIM ===== */
.reveal{opacity:0;transform:translateY(24px);transition:opacity .6s ease,transform .6s ease}
.reveal.visible{opacity:1;transform:translateY(0)}
/* ===== MOBILE ===== */
@media(max-width:900px){
  .nav-menu{
    position:fixed;top:64px;left:0;right:0;
    background:var(--nav-bg);backdrop-filter:blur(12px);
    flex-direction:column;align-items:stretch;gap:0;
    padding:.5rem 1rem 1rem;border-bottom:1px solid var(--border);
    transform:translateY(-120%);transition:transform .3s ease;
    max-height:calc(100vh - 64px);overflow-y:auto;
  }
  .nav-menu.open{transform:translateY(0)}
  .nav-menu a{padding:.8rem 1rem;border-radius:8px}
  .menu-toggle{display:flex}
  .search-box input{width:120px}
  h1{font-size:1.6rem}
  h2{font-size:1.35rem}
  .banner-content h2{font-size:1.5rem}
  .banner-content p{font-size:.95rem}
}
@media(max-width:480px){
  .search-box{display:none}
  .nav-logo em{display:none}
  .banner-content h2{font-size:1.3rem}
  .footer-bottom{flex-direction:column;text-align:center}
}