/* ============================================================
   NIKACOOL — Auto AC Parts B2B Site
   纯静态样式,无框架依赖
   ============================================================ */
*{margin:0;padding:0;box-sizing:border-box}
:root{
  --navy:#12283f; --navy-2:#1c3c60; --accent:#f26a21; --accent-dark:#d95c1a;
  --bg:#f5f7fa; --card:#fff; --text:#22303e; --muted:#64748b;
  --border:#e3e9f0; --radius:12px;
  --shadow:0 2px 10px rgba(18,40,63,.08);
  --shadow-lg:0 10px 24px rgba(18,40,63,.12);
}
html{scroll-behavior:smooth}
body{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,"Noto Sans","PingFang SC","Microsoft YaHei",sans-serif;color:var(--text);background:var(--bg);line-height:1.6;-webkit-font-smoothing:antialiased}
img{max-width:100%;display:block}
a{color:inherit;text-decoration:none}
button{font-family:inherit}
.container{max-width:1200px;margin:0 auto;padding:0 20px}
.muted{color:var(--muted);font-size:14px}
.center{text-align:center;margin-top:36px}

/* ---------- 按钮 ---------- */
.btn{display:inline-block;padding:12px 24px;border-radius:8px;font-weight:700;font-size:15px;transition:.2s;border:2px solid transparent;cursor:pointer}
.btn-primary{background:var(--accent);color:#fff}
.btn-primary:hover{background:var(--accent-dark)}
.btn-ghost{border-color:rgba(255,255,255,.55);color:#fff}
.btn-ghost:hover{background:rgba(255,255,255,.12)}
.btn-outline{border-color:var(--navy-2);color:var(--navy-2);background:#fff}
.btn-outline:hover{background:var(--navy-2);color:#fff}
.btn-sm{padding:8px 16px;font-size:14px}
.btn-whatsapp{background:#25d366;color:#fff}
.btn-whatsapp:hover{background:#1fb955}

/* ---------- 头部导航 ---------- */
.site-header{position:sticky;top:0;background:#fff;border-bottom:1px solid var(--border);z-index:50}
.nav-wrap{display:flex;align-items:center;justify-content:space-between;height:68px}
.logo img{height:42px;width:auto}
nav#mainNav{display:flex;align-items:center;gap:26px;font-weight:600;font-size:15px}
nav#mainNav a{color:#3c4a59;padding:6px 0;border-bottom:2px solid transparent}
nav#mainNav a:hover{color:var(--accent)}
nav#mainNav a.active{color:var(--accent);border-bottom-color:var(--accent)}
.nav-toggle{display:none;background:none;border:0;font-size:26px;color:var(--navy);cursor:pointer;line-height:1}

/* ---------- Hero ---------- */
.hero{background:linear-gradient(130deg,#0f2236 0%,#17395c 55%,#1f4f7d 100%);color:#fff;padding:88px 0 64px;position:relative;overflow:hidden}
.hero::after{content:"";position:absolute;inset:0;background-image:radial-gradient(rgba(255,255,255,.10) 1.5px,transparent 1.6px);background-size:26px 26px;pointer-events:none}
.hero-text{max-width:780px;position:relative;z-index:1}
.eyebrow{letter-spacing:3px;font-size:13px;font-weight:700;color:#ffb489;margin-bottom:14px}
.hero h1{font-size:44px;line-height:1.15;letter-spacing:-.5px;margin-bottom:16px}
.hero .sub{font-size:18px;color:#c8d6e5;max-width:660px;margin-bottom:28px}
.hero-cta{display:flex;gap:14px;flex-wrap:wrap;margin-bottom:40px}
.stats{display:flex;gap:44px;flex-wrap:wrap;border-top:1px solid rgba(255,255,255,.18);padding-top:24px}
.stats b{font-size:26px;display:block;line-height:1.2}
.stats span{color:#a9bccf;font-size:12.5px;letter-spacing:1px;text-transform:uppercase}

/* ---------- 区块 ---------- */
.section{padding:64px 0}
.section.alt{background:#eef2f7}
.section-head{max-width:660px;margin-bottom:36px}
.section-head h2{font-size:30px;color:var(--navy);letter-spacing:-.3px}
.section-head p{color:var(--muted);margin-top:6px}
.grid{display:grid;gap:22px}
.cat-grid{grid-template-columns:repeat(auto-fill,minmax(250px,1fr))}
.prod-grid{grid-template-columns:repeat(auto-fill,minmax(240px,1fr))}

/* ---------- 品类卡 ---------- */
.cat-card{background:#fff;border:1px solid var(--border);border-radius:var(--radius);overflow:hidden;transition:.2s;box-shadow:var(--shadow);display:flex;flex-direction:column}
.cat-card:hover{transform:translateY(-4px);box-shadow:var(--shadow-lg)}
.cat-card img{width:100%;aspect-ratio:4/3;object-fit:cover}
.cat-card-body{padding:16px 18px}
.cat-card-body h3{font-size:17px;color:var(--navy)}
.cat-card-body p{color:var(--accent);font-size:13px;font-weight:700;margin-top:4px}

/* ---------- 产品卡 ---------- */
.prod-card{background:#fff;border:1px solid var(--border);border-radius:var(--radius);overflow:hidden;transition:.2s;display:flex;flex-direction:column;box-shadow:var(--shadow)}
.prod-card:hover{transform:translateY(-4px);box-shadow:var(--shadow-lg)}
.prod-card img{width:100%;aspect-ratio:4/3;object-fit:cover;background:#d6e8f6}
.prod-card-body{padding:15px 17px;display:flex;flex-direction:column;gap:7px;flex:1}
.prod-card-body .tag{font-size:11px;font-weight:700;letter-spacing:1px;text-transform:uppercase;color:var(--accent)}
.prod-card-body h3{font-size:15px;line-height:1.45;color:var(--navy)}
.prod-card-body .sku{font-size:12.5px;color:var(--muted);font-family:ui-monospace,SFMono-Regular,Menlo,monospace}
.prod-card-body .view{margin-top:auto;color:var(--accent);font-weight:700;font-size:14px}

/* ---------- 列表页头/搜索 ---------- */
.page-head{background:linear-gradient(130deg,#0f2236,#1c3c60);color:#fff;padding:52px 0}
.page-head h1{font-size:34px}
.page-head p{color:#c8d6e5;margin-top:6px;max-width:640px}
.search-bar{display:flex;gap:10px;margin-top:22px;max-width:600px}
.search-bar input{flex:1;padding:12px 16px;border-radius:8px;border:1px solid #cfd9e4;font-size:15px}
.chips{display:flex;flex-wrap:wrap;gap:10px;margin-top:18px}
.chip{padding:8px 16px;border-radius:999px;border:1px solid rgba(255,255,255,.35);background:transparent;color:#dbe6f0;font-size:14px;font-weight:600;cursor:pointer;transition:.15s}
.chip:hover{border-color:#fff}
.chip.active{background:#fff;color:var(--navy)}
#resultCount{margin-bottom:18px}
.empty{padding:36px 0;color:var(--muted)}
.empty a{color:var(--accent);font-weight:600}

/* ---------- 产品详情 ---------- */
.breadcrumb{font-size:13.5px;color:var(--muted);margin-bottom:22px}
.breadcrumb a:hover{color:var(--accent)}
.pd-grid{display:grid;grid-template-columns:1fr 1fr;gap:40px;align-items:start}
.pd-media{background:#fff;border:1px solid var(--border);border-radius:var(--radius);overflow:hidden}
.pd-media img{width:100%}
.pd-info h1{font-size:27px;color:var(--navy);line-height:1.25}
.pd-info .sku{color:var(--muted);font-size:13.5px;margin:10px 0 14px;font-family:ui-monospace,Menlo,monospace}
.pd-info .lead{font-size:16px;margin-bottom:18px}
.keyspecs{list-style:none;border:1px solid var(--border);border-radius:10px;overflow:hidden;margin-bottom:22px;background:#fff}
.keyspecs li{display:flex;justify-content:space-between;gap:16px;padding:9px 14px;font-size:14px;border-bottom:1px solid var(--border)}
.keyspecs li:last-child{border-bottom:0}
.keyspecs span{color:var(--muted)}
.keyspecs b{text-align:right}
.pd-cta{display:flex;gap:12px;flex-wrap:wrap}
.pd-sections{margin-top:52px;display:grid;gap:34px;max-width:920px}
.pd-sections h2,.related h2{font-size:21px;color:var(--navy);margin-bottom:12px;padding-bottom:8px;border-bottom:2px solid var(--accent);display:inline-block}
.spec-table{width:100%;max-width:820px;border-collapse:collapse;background:#fff;border:1px solid var(--border)}
.spec-table td{padding:10px 14px;border-bottom:1px solid var(--border);font-size:14.5px}
.spec-table tr:last-child td{border-bottom:0}
.spec-table td:first-child{color:var(--muted);width:34%}
.oe-chips{display:flex;flex-wrap:wrap;gap:10px;max-width:820px}
.oe{background:#fff;border:1px dashed #b9c8d8;border-radius:8px;padding:7px 13px;font-family:ui-monospace,Menlo,monospace;font-size:13.5px}
.note{color:var(--muted);font-size:13px;margin-top:10px}
.related{margin-top:52px}
.related .grid{margin-top:8px}
.inquiry-box{background:#fff;border:1px solid var(--border);border-radius:var(--radius);padding:30px;margin-top:52px;max-width:780px;box-shadow:var(--shadow)}
.inquiry-box h2{font-size:22px;color:var(--navy);margin-bottom:4px}
.inquiry-box .muted{margin-bottom:18px}

/* ---------- 表单 ---------- */
.form-grid{display:grid;grid-template-columns:1fr 1fr;gap:14px}
.form-grid .full{grid-column:1/-1}
.field label{display:block;font-size:13.5px;font-weight:600;margin-bottom:6px;color:#33465a}
.field input,.field select,.field textarea{width:100%;padding:11px 14px;border:1px solid #cfd9e4;border-radius:8px;font-size:15px;font-family:inherit;background:#fff}
.field input:focus,.field select:focus,.field textarea:focus{outline:2px solid rgba(242,106,33,.35);border-color:var(--accent)}
form .btn{margin-top:16px}

/* ---------- 联系页 ---------- */
.contact-grid{display:grid;grid-template-columns:340px 1fr;gap:34px;align-items:start}
.info-card{background:#fff;border:1px solid var(--border);border-radius:var(--radius);padding:18px 20px;display:flex;gap:14px;margin-bottom:14px}
.info-card .ic{font-size:20px;line-height:1.4}
.info-card h4{font-size:15px;color:var(--navy)}
.info-card p{font-size:14px;color:var(--muted)}

/* ---------- 关于页 ---------- */
.about-story{max-width:840px}
.about-story p{margin-bottom:16px;font-size:15.5px}
.value-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(230px,1fr));gap:22px;margin-top:10px}
.value{background:#fff;border:1px solid var(--border);border-radius:var(--radius);padding:24px}
.value h3{color:var(--navy);font-size:17px;margin-bottom:6px}
.value p{color:var(--muted);font-size:14.5px}

/* ---------- 特性卡 ---------- */
.features-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(230px,1fr));gap:22px}
.feature{background:#fff;border:1px solid var(--border);border-radius:var(--radius);padding:26px}
.feature .k{color:var(--accent);font-weight:800;font-size:12px;letter-spacing:2px}
.feature h3{color:var(--navy);margin:8px 0 6px;font-size:18px}
.feature p{color:var(--muted);font-size:14.5px}

/* ---------- CTA 横幅 ---------- */
.cta-band{background:linear-gradient(120deg,var(--accent),#e04b00);color:#fff;padding:54px 0;text-align:center}
.cta-band h2{font-size:28px;margin-bottom:8px}
.cta-band p{opacity:.92;margin-bottom:22px}
.cta-band .btn{background:#fff;color:var(--accent-dark);border:0}
.cta-band .btn:hover{background:#fff3ea}

/* ---------- 页脚 ---------- */
.site-footer{background:#0f2236;color:#b8c7d6}
.footer-wrap{display:grid;grid-template-columns:2fr 1fr 1fr 1.4fr;gap:34px;padding:54px 0 40px}
.f-logo{font-weight:800;font-size:22px;color:#fff;letter-spacing:2px}
.f-blurb{margin-top:10px;font-size:14px;color:#9fb1c4;max-width:300px}
.site-footer h4{color:#fff;font-size:15px;margin-bottom:14px;letter-spacing:.5px}
.site-footer a{display:block;padding:3px 0;font-size:14px;color:#9fb1c4}
.site-footer a:hover{color:#fff}
.f-contact{font-size:14px;line-height:1.9;color:#9fb1c4}
.footer-bottom{border-top:1px solid rgba(255,255,255,.12);padding:18px 0;font-size:13px;color:#8296ab;display:flex;justify-content:space-between;flex-wrap:wrap;gap:8px}

/* ---------- WhatsApp 浮动按钮 ---------- */
.wa-float{position:fixed;right:20px;bottom:20px;width:54px;height:54px;border-radius:50%;background:#25d366;display:flex;align-items:center;justify-content:center;box-shadow:0 6px 18px rgba(0,0,0,.28);z-index:60;transition:.2s}
.wa-float:hover{transform:scale(1.08)}
.wa-float svg{width:30px;height:30px;fill:#fff}

/* ---------- 响应式 ---------- */
@media(max-width:860px){
  .nav-toggle{display:block}
  nav#mainNav{position:absolute;top:68px;left:0;right:0;background:#fff;flex-direction:column;align-items:flex-start;padding:16px 20px 20px;display:none;border-bottom:1px solid var(--border);box-shadow:var(--shadow-lg)}
  nav#mainNav.open{display:flex}
  .pd-grid{grid-template-columns:1fr}
  .hero h1{font-size:33px}
  .hero{padding:60px 0 48px}
  .stats{gap:28px}
  .contact-grid{grid-template-columns:1fr}
  .form-grid{grid-template-columns:1fr}
  .footer-wrap{grid-template-columns:1fr 1fr}
}
@media(max-width:560px){
  .footer-wrap{grid-template-columns:1fr}
  .section{padding:48px 0}
  .search-bar{flex-direction:column}
}