/* ========================================
   XuZhiShi — Navigation (from index2.html)
   Mega-menu nav with scroll-to-pill behavior
   ======================================== */

.nav{position:fixed;top:0;left:0;right:0;z-index:1000;height:var(--nav-height);display:flex;align-items:center;padding:0 clamp(1.5rem,4vw,3rem);background:transparent;backdrop-filter:none;-webkit-backdrop-filter:none;border:none;transition:all 0.6s var(--ease-out);width:100%;max-width:100%;border-radius:0;box-shadow:none;transform:none}
.nav.menu-open{background:rgba(255,255,255,0.98);backdrop-filter:blur(40px) saturate(1.8);-webkit-backdrop-filter:blur(40px) saturate(1.8);box-shadow:none}
.nav.scrolled{top:12px;left:50%;right:auto;transform:translateX(-50%);width:90%;max-width:900px;border-radius:100px;background:rgba(255,255,255,0.92);backdrop-filter:blur(40px) saturate(1.8);-webkit-backdrop-filter:blur(40px) saturate(1.8);border:1px solid rgba(0,0,0,0.06);box-shadow:var(--shadow-md);padding:0 2rem;overflow:visible;transition:all 0.5s var(--ease-out),border-radius 0.3s}
.nav.scrolled.menu-open{border-radius:var(--radius-md) var(--radius-md) 0 0;border-bottom-color:transparent}
.nav-logo{font-size:1rem;font-weight:600;color:var(--text);text-decoration:none;display:flex;align-items:center;gap:0.5rem;flex-shrink:0;transition:color 0.4s}
.nav-logo img{height:38px;width:auto;object-fit:contain}
.logo-light{display:none}
.logo-dark{display:block}
.nav-links{display:flex;align-items:center;gap:0.25rem;margin-left:auto;list-style:none;position:relative;padding:4px;border-radius:99px}
.nav-indicator{position:absolute;top:4px;left:0;height:calc(100% - 8px);background:rgba(0,113,227,0.06);border-radius:99px;pointer-events:none;z-index:0;transition:width 0.4s cubic-bezier(0.2,0.8,0.2,1),transform 0.4s cubic-bezier(0.2,0.8,0.2,1),opacity 0.25s ease;opacity:0}
.nav-links>li{position:relative;z-index:1}
.nav.scrolled .nav-links>li{position:static}
.nav-links>li>a{font-size:0.8125rem;font-weight:500;color:var(--text);text-decoration:none;transition:color 0.3s;padding:0.5rem 0.75rem;border-radius:8px;display:flex;align-items:center;gap:0.25rem;position:relative;z-index:2}
.nav-links>li>a:hover{color:var(--primary)}
.nav-links>li>a .nav-arrow{font-size:0.5rem;transition:transform 0.3s}
.nav-links>li:hover>a .nav-arrow{transform:rotate(180deg)}
.nav-links>li>a::after{content:'';position:absolute;bottom:-8px;left:0;right:0;height:16px}

/* Mega-menu dropdown */
.nav-dropdown{position:fixed;top:var(--nav-height);left:0;right:0;opacity:0;visibility:hidden;pointer-events:none;transition:all 0.35s var(--ease-out);background:rgba(255,255,255,0.98);backdrop-filter:blur(40px) saturate(1.8);-webkit-backdrop-filter:blur(40px) saturate(1.8);border-bottom:1px solid var(--card-border);box-shadow:0 20px 60px rgba(0,0,0,0.06);list-style:none;padding:0;z-index:999;transform:translateY(0)}
.nav.scrolled .nav-dropdown{position:fixed;top:calc(12px + var(--nav-height));left:50%;right:auto;transform:translateX(-50%);width:90%;max-width:900px;border-radius:0 0 var(--radius-md) var(--radius-md);border:1px solid rgba(0,0,0,0.06);border-top:none;box-shadow:var(--shadow-lg);margin-top:0;background:rgba(255,255,255,0.98)}
.nav.scrolled .nav-dropdown .mega-inner{max-width:100%;padding:1.5rem 2rem 2rem;gap:2rem;grid-template-columns:160px 1fr}
.nav-dropdown.show{opacity:1;visibility:visible;pointer-events:auto;transform:translateY(0)}
.nav.scrolled .nav-dropdown.show{transform:translateX(-50%);margin-top:-1px;width:100%}
.mega-inner{max-width:1100px;margin:0 auto;display:grid;grid-template-columns:200px 1fr;gap:3rem;padding:2.5rem clamp(1.5rem,4vw,3rem)}
.mega-panels{position:relative;min-height:240px}
.mega-panels .mega-content{position:absolute;inset:0;opacity:0;visibility:hidden;transition:all 0.3s var(--ease-out);transform:translateY(6px);display:grid;grid-template-columns:repeat(auto-fill,minmax(180px,1fr));gap:1.5rem;align-content:start}
.mega-panels .mega-content.active{position:relative;opacity:1;visibility:visible;transform:translateY(0)}
.mega-cats{border-right:1px solid var(--card-border);padding-right:2rem}
.mega-cat-label{font-size:0.6875rem;font-weight:600;letter-spacing:0.08em;text-transform:uppercase;color:var(--text-muted);margin-bottom:0.75rem;display:block}
.mega-cat-item{display:block;font-size:1.25rem;font-weight:600;color:var(--text-muted);padding:0.5rem 0;cursor:pointer;transition:all 0.3s;text-decoration:none;border:none;background:none;width:100%;text-align:left;font-family:var(--font)}
.mega-cat-item:hover,.mega-cat-item.active{color:var(--text)}
.mega-product{text-align:center;padding:1.25rem;border-radius:var(--radius-sm);transition:all 0.3s;text-decoration:none;color:var(--text)}
.mega-product:hover{background:var(--bg-secondary)}
.mega-product img{width:100%;max-width:160px;height:120px;object-fit:contain;margin:0 auto 0.75rem;display:block;transition:transform 0.4s var(--ease-spring)}
.mega-product:hover img{transform:scale(1.05)}
.mega-product .mp-name{font-size:0.875rem;font-weight:600;margin-bottom:0.25rem}
.mega-product .mp-desc{font-size:0.75rem;color:var(--text-muted)}
.mega-links{display:flex;flex-direction:column;gap:0.25rem}
.mega-link{display:block;padding:0.6rem 0.75rem;font-size:0.875rem;color:var(--text-secondary);text-decoration:none;border-radius:8px;transition:all 0.2s;font-weight:400}
.mega-link:hover{color:var(--primary);background:rgba(0,113,227,0.04)}
.mega-link-title{font-weight:600;color:var(--text);font-size:0.9375rem;margin-bottom:0.15rem}
.mega-link-sub{font-size:0.75rem;color:var(--text-muted)}
.nav-cta{margin-left:1rem;padding:0.5rem 1.25rem;border-radius:100px;font-size:0.8125rem;font-weight:500;color:#fff;background:var(--primary);text-decoration:none;transition:all 0.3s var(--ease);border:none}
.nav-cta:hover{background:var(--primary-light);box-shadow:var(--shadow-glow);transform:scale(1.03)}

/* Mobile menu toggle */
.nav-mobile-toggle{display:none;width:36px;height:36px;border-radius:50%;border:none;background:transparent;cursor:pointer;position:relative;align-items:center;justify-content:center}
.nav-mobile-toggle span,.nav-mobile-toggle span::before,.nav-mobile-toggle span::after{display:block;width:18px;height:1.5px;background:var(--text);border-radius:2px;transition:all 0.3s var(--ease)}
.nav-mobile-toggle span::before,.nav-mobile-toggle span::after{content:'';position:absolute;left:50%;transform:translateX(-50%)}
.nav-mobile-toggle span::before{top:calc(50% - 5px)}
.nav-mobile-toggle span::after{top:calc(50% + 5px)}
.nav-mobile-toggle.open span{background:transparent}
.nav-mobile-toggle.open span::before{top:50%;transform:translateX(-50%) rotate(45deg)}
.nav-mobile-toggle.open span::after{top:50%;transform:translateX(-50%) rotate(-45deg)}

/* Mobile menu container */
.nav-mobile-menu{display:none;position:fixed;top:calc(var(--nav-height) + 8px);left:0;right:0;bottom:0;background:rgba(255,255,255,0.98);backdrop-filter:blur(40px);-webkit-backdrop-filter:blur(40px);z-index:999;padding:1.25rem 1.25rem 2rem;overflow-y:auto;overscroll-behavior:contain;flex-direction:column;gap:0.25rem;opacity:0;transform:translateY(-8px);transition:all 0.3s var(--ease-out)}
.nav-mobile-menu.open{display:flex;opacity:1;transform:translateY(0)}

/* Simple link */
.mm-link{display:block;font-size:1.1rem;font-weight:500;color:var(--text);text-decoration:none;padding:0.9rem 0.5rem;border-bottom:1px solid rgba(0,0,0,0.04);transition:color 0.2s}
.mm-link:hover{color:var(--primary)}

/* Level 1 accordion button */
.mm-group{border-bottom:1px solid rgba(0,0,0,0.04)}
.mm-l1{display:flex;align-items:center;justify-content:space-between;width:100%;padding:0.9rem 0.5rem;font-size:1.1rem;font-weight:500;color:var(--text);background:none;border:none;cursor:pointer;font-family:var(--font);transition:color 0.2s}
.mm-l1:hover{color:var(--primary)}
.mm-arrow{font-size:0.7rem;transition:transform 0.3s var(--ease-out);color:var(--text-muted)}
.mm-l1[aria-expanded="true"] .mm-arrow{transform:rotate(180deg)}

/* Level 1 panel */
.mm-panel{max-height:0;overflow:hidden;transition:max-height 0.4s var(--ease-out)}
.mm-panel.open{max-height:600px}

/* Level 2 tabs */
.mm-tabs{display:flex;gap:0.375rem;padding:0.25rem 0.5rem 0.75rem;overflow-x:auto;-webkit-overflow-scrolling:touch}
.mm-tabs::-webkit-scrollbar{display:none}
.mm-tab{flex-shrink:0;padding:0.45rem 0.9rem;font-size:0.75rem;font-weight:500;color:var(--text-muted);background:var(--bg-secondary);border:none;border-radius:100px;cursor:pointer;font-family:var(--font);transition:all 0.25s}
.mm-tab.active{background:var(--primary);color:#fff}

/* Level 3 card container */
.mm-cards{display:none;flex-direction:column;gap:0.5rem;padding:0 0.5rem 0.75rem}
.mm-cards.active{display:flex}

/* Level 3 card strips */
.mm-card{display:flex;align-items:center;gap:0.75rem;padding:0.85rem 1rem;background:var(--bg);border-radius:12px;border:1px solid var(--card-border);text-decoration:none;transition:all 0.25s}
.mm-card:active{background:var(--bg-secondary);transform:scale(0.985)}
.mm-card-body{flex:1;min-width:0}
.mm-card-title{display:block;font-size:0.875rem;font-weight:600;color:var(--text);margin-bottom:0.15rem}
.mm-card-desc{display:block;font-size:0.75rem;color:var(--text-muted);line-height:1.45;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.mm-card-arrow{font-size:0.875rem;color:var(--text-muted);flex-shrink:0;opacity:0.5;transition:opacity 0.2s}
.mm-card:hover .mm-card-arrow,.mm-card:active .mm-card-arrow{opacity:1}

/* CTA button */
.nav-mobile-menu .nav-mobile-cta{display:flex;align-items:center;justify-content:center;margin-top:1rem;padding:0.9rem 2rem;border-radius:100px;background:var(--primary);color:#fff;font-weight:500;font-size:0.95rem;text-align:center;text-decoration:none}

/* Responsive */
@media(max-width:767px){
  .nav{background:rgba(255,255,255,0.92);backdrop-filter:blur(40px) saturate(1.8);-webkit-backdrop-filter:blur(40px) saturate(1.8);border-bottom:1px solid rgba(0,0,0,0.06)}
  .nav .nav-logo{color:#1d1d1f}
  .nav .logo-light{display:none}
  .nav .logo-dark{display:block}
  .nav .nav-mobile-toggle span,.nav .nav-mobile-toggle span::before,.nav .nav-mobile-toggle span::after{background:#1d1d1f}
  .nav.scrolled{width:95%;padding:0 1rem}
  .nav-links{display:none}
  .nav-cta{display:none}
  .nav-mobile-toggle{display:flex;margin-left:auto}
  .nav.menu-open{background:rgba(255,255,255,0.98);backdrop-filter:blur(40px) saturate(1.8);-webkit-backdrop-filter:blur(40px) saturate(1.8)}
}