/*
Theme Name: Unistars
Theme URI: https://www.unistars.com.cn/
Author: Unistars Design Team
Description: Custom WordPress theme for Unistars Plastics Additives — professional methyl tin stabilizer manufacturer. B2B industrial design, fully responsive, English-first.
Version: 1.0.0
Text Domain: unistars
*/

/* ============================================
   RESET & BASE
   ============================================ */
*,*::before,*::after{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{font-family:'Inter','Helvetica Neue',Arial,sans-serif;color:#1A2332;background:#F5F7FA;line-height:1.6;-webkit-font-smoothing:antialiased}
img{max-width:100%;height:auto;display:block}
a{text-decoration:none;color:inherit;transition:color .2s}
ul,ol{list-style:none}
h1,h2,h3,h4,h5,h6{line-height:1.3;font-weight:700}
.container{max-width:1200px;margin:0 auto;padding:0 24px}

/* ============================================
   CSS VARIABLES
   ============================================ */
:root{
  --navy-900:#0B1F3A;--navy-800:#0F2B46;--navy-700:#163D63;--navy-600:#1E4D7E;
  --teal-500:#0D9488;--teal-400:#14B8A6;--teal-300:#5EEAD4;
  --bg-light:#F5F7FA;--bg-white:#FFF;--text-dark:#1A2332;--text-muted:#64748B;--text-light:#94A3B8;
  --border:#E2E8F0;--gold:#C9A961;
  --shadow-sm:0 1px 3px rgba(15,43,70,.08);
  --shadow-md:0 4px 16px rgba(15,43,70,.10);
  --shadow-lg:0 12px 40px rgba(15,43,70,.15);
  --radius:8px;--radius-lg:14px;
}

/* ============================================
   TOP BAR
   ============================================ */
.topbar{background:var(--navy-900);color:#94A3B8;font-size:13px;padding:6px 0}
.topbar .container{display:flex;justify-content:space-between;align-items:center;flex-wrap:wrap;gap:8px}
.topbar .contact-info span{margin-right:24px}
.topbar .lang a{color:#94A3B8;margin-left:16px}
.topbar .lang a.active,.topbar .lang a:hover{color:#fff}

/* ============================================
   HEADER
   ============================================ */
.site-header{background:#fff;box-shadow:var(--shadow-sm);position:sticky;top:0;z-index:1000}
.site-header .container{display:flex;justify-content:space-between;align-items:center;height:80px}
.site-logo{display:flex;align-items:center;gap:12px}
.site-logo .logo-icon{width:42px;height:42px;background:linear-gradient(135deg,var(--teal-500),var(--navy-700));border-radius:10px;display:flex;align-items:center;justify-content:center;color:#fff;font-weight:800;font-size:18px}
.site-logo .logo-text .name{font-size:20px;font-weight:800;color:var(--navy-800);letter-spacing:1px;line-height:1.2}
.site-logo .logo-text .sub{font-size:11px;color:var(--text-muted);letter-spacing:2px}

.main-nav ul{display:flex;gap:4px;align-items:center}
.main-nav>ul>li>a{padding:10px 18px;font-size:15px;color:var(--text-dark);font-weight:500;border-radius:6px;display:block}
.main-nav>ul>li>a:hover,.main-nav>ul>li.current-menu-item>a{color:var(--teal-500);background:rgba(20,184,166,.08)}
.main-nav li{position:relative}
.main-nav ul ul{display:none;position:absolute;top:100%;left:0;background:#fff;min-width:220px;border-radius:0 0 8px 8px;box-shadow:var(--shadow-md);padding:8px 0;flex-direction:column}
.main-nav li:hover>ul{display:flex}
.main-nav ul ul a{padding:10px 20px;font-size:14px;color:var(--text-dark);display:block}
.main-nav ul ul a:hover{background:var(--bg-light);color:var(--teal-500)}

.header-cta{background:var(--teal-500);color:#fff!important;padding:10px 24px;border-radius:6px;font-size:14px;font-weight:600}
.header-cta:hover{background:var(--navy-700)}

/* Mobile menu toggle */
.menu-toggle{display:none;background:none;border:none;cursor:pointer;padding:8px;flex-direction:column;gap:5px}
.menu-toggle span{display:block;width:26px;height:3px;background:var(--navy-800);border-radius:2px;transition:all .3s}

/* ============================================
   HERO
   ============================================ */
.hero{background:linear-gradient(135deg,var(--navy-900) 0%,var(--navy-700) 60%,var(--navy-600) 100%);color:#fff;padding:100px 0 120px;position:relative;overflow:hidden}
.hero::before{content:"";position:absolute;right:-100px;top:-100px;width:500px;height:500px;border-radius:50%;background:radial-gradient(circle,rgba(20,184,166,.15) 0%,transparent 70%)}
.hero::after{content:"";position:absolute;left:20%;bottom:-150px;width:400px;height:400px;border-radius:50%;background:radial-gradient(circle,rgba(201,169,97,.08) 0%,transparent 70%)}
.hero .container{position:relative;z-index:2;display:grid;grid-template-columns:1.2fr 1fr;gap:60px;align-items:center}
.hero-tag{display:inline-block;background:rgba(20,184,166,.15);color:var(--teal-300);padding:6px 16px;border-radius:20px;font-size:13px;margin-bottom:24px;border:1px solid rgba(20,184,166,.3)}
.hero h1{font-size:44px;line-height:1.2;font-weight:800;margin-bottom:20px}
.hero h1 .accent{color:var(--teal-400)}
.hero p{font-size:17px;color:#B8C5D6;margin-bottom:36px;max-width:520px}
.hero-btns{display:flex;gap:16px;flex-wrap:wrap}
.btn-primary{background:var(--teal-500);color:#fff;padding:14px 32px;border-radius:6px;font-weight:600;font-size:15px;display:inline-block;transition:all .2s;border:none;cursor:pointer}
.btn-primary:hover{background:#0F766E;transform:translateY(-2px);box-shadow:0 8px 20px rgba(20,184,166,.3);color:#fff}
.btn-outline{border:1px solid rgba(255,255,255,.3);color:#fff;padding:14px 32px;border-radius:6px;font-weight:500;font-size:15px;display:inline-block;transition:all .2s}
.btn-outline:hover{background:rgba(255,255,255,.1);color:#fff}
.hero-visual{background:rgba(255,255,255,.05);border:1px solid rgba(255,255,255,.1);border-radius:var(--radius-lg);padding:32px;backdrop-filter:blur(10px)}
.hero-visual .mol-title{font-size:13px;color:var(--teal-300);margin-bottom:16px;letter-spacing:1px}
.hero-visual .mol-formula{font-size:20px;color:#fff;font-family:'Courier New',monospace;padding:20px;background:rgba(11,31,58,.4);border-radius:8px;margin-bottom:20px;border-left:3px solid var(--teal-400);word-break:break-all}
.hero-visual .spec-row{display:flex;justify-content:space-between;padding:10px 0;border-bottom:1px solid rgba(255,255,255,.08);font-size:14px}
.hero-visual .spec-row .label{color:#94A3B8}
.hero-visual .spec-row .val{color:#fff;font-weight:600}

/* ============================================
   STATS
   ============================================ */
.stats{background:#fff;margin-top:-60px;position:relative;z-index:10;border-radius:var(--radius-lg);box-shadow:var(--shadow-lg);padding:40px 0}
.stats .container{display:grid;grid-template-columns:repeat(4,1fr);gap:0}
.stat{text-align:center;padding:0 20px;border-right:1px solid var(--border)}
.stat:last-child{border-right:none}
.stat .num{font-size:36px;font-weight:800;color:var(--navy-800)}
.stat .num span{color:var(--teal-500);font-size:20px}
.stat .label{font-size:14px;color:var(--text-muted);margin-top:6px}

/* ============================================
   SECTIONS
   ============================================ */
section{padding:90px 0}
.section-tag{text-align:center;color:var(--teal-500);font-size:14px;font-weight:600;letter-spacing:3px;margin-bottom:12px;text-transform:uppercase}
.section-title{text-align:center;font-size:32px;font-weight:800;color:var(--navy-800);margin-bottom:16px}
.section-desc{text-align:center;color:var(--text-muted);font-size:16px;max-width:600px;margin:0 auto 50px}

/* ============================================
   CATEGORY CARDS
   ============================================ */
.categories{background:#fff}
.cat-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:24px}
.cat-card{background:var(--bg-light);border-radius:var(--radius-lg);padding:36px 28px;transition:all .3s;border:1px solid transparent;display:block}
.cat-card:hover{background:#fff;box-shadow:var(--shadow-md);border-color:var(--border);transform:translateY(-4px)}
.cat-icon{width:56px;height:56px;border-radius:12px;background:linear-gradient(135deg,var(--teal-500),var(--teal-400));display:flex;align-items:center;justify-content:center;font-size:26px;color:#fff;margin-bottom:20px}
.cat-card h3{font-size:19px;font-weight:700;color:var(--navy-800);margin-bottom:10px}
.cat-card p{font-size:14px;color:var(--text-muted);margin-bottom:16px;line-height:1.6}
.cat-card .link{color:var(--teal-500);font-size:14px;font-weight:600}

/* ============================================
   PRODUCT CARDS
   ============================================ */
.featured{background:var(--bg-light)}
.prod-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:28px}
.prod-card{background:#fff;border-radius:var(--radius-lg);overflow:hidden;box-shadow:var(--shadow-sm);transition:all .3s;display:block}
.prod-card:hover{box-shadow:var(--shadow-lg);transform:translateY(-6px)}
.prod-img{height:200px;background:linear-gradient(135deg,var(--navy-700),var(--navy-900));display:flex;align-items:center;justify-content:center;position:relative}
.prod-img .badge{position:absolute;top:16px;left:16px;background:var(--gold);color:#fff;font-size:11px;padding:4px 12px;border-radius:12px;font-weight:600;z-index:2}
.prod-img .mol{font-size:15px;color:var(--teal-300);font-family:'Courier New',monospace;text-align:center;padding:0 20px}
.prod-body{padding:24px}
.prod-body .code{font-size:12px;color:var(--teal-500);font-weight:600;letter-spacing:1px;margin-bottom:6px}
.prod-body h3{font-size:18px;font-weight:700;color:var(--navy-800);margin-bottom:10px}
.prod-body p{font-size:14px;color:var(--text-muted);margin-bottom:18px;line-height:1.6}
.prod-body .spec-mini{display:flex;gap:16px;font-size:12px;color:var(--text-light);border-top:1px solid var(--border);padding-top:14px;flex-wrap:wrap}
.prod-body .spec-mini span b{color:var(--text-dark)}

/* ============================================
   ABOUT SECTION
   ============================================ */
.about{background:#fff}
.about .container{display:grid;grid-template-columns:1fr 1fr;gap:60px;align-items:center}
.about-visual{background:linear-gradient(135deg,var(--navy-800),var(--navy-900));border-radius:var(--radius-lg);padding:50px;min-height:400px;display:flex;flex-direction:column;justify-content:center;position:relative;overflow:hidden}
.about-visual::before{content:"";position:absolute;right:-60px;bottom:-60px;width:250px;height:250px;border-radius:50%;background:rgba(20,184,166,.15)}
.about-visual .big-num{font-size:72px;font-weight:800;color:var(--teal-400);line-height:1}
.about-visual .big-label{color:#B8C5D6;font-size:16px;margin-top:8px}
.about-text .section-tag{text-align:left}
.about-text h2{font-size:32px;font-weight:800;color:var(--navy-800);margin-bottom:20px;line-height:1.3}
.about-text>p{color:var(--text-muted);font-size:15px;margin-bottom:24px;line-height:1.7}
.feature-list{list-style:none}
.feature-list li{display:flex;gap:14px;margin-bottom:18px;align-items:flex-start}
.feature-list .check{width:24px;height:24px;border-radius:50%;background:var(--teal-500);color:#fff;display:flex;align-items:center;justify-content:center;font-size:13px;flex-shrink:0;margin-top:2px}
.feature-list .txt b{display:block;color:var(--navy-800);font-size:15px;margin-bottom:2px}
.feature-list .txt span{font-size:14px;color:var(--text-muted)}

/* ============================================
   CERTIFICATIONS
   ============================================ */
.certs{background:var(--navy-900);color:#fff;padding:60px 0}
.certs .container{display:flex;justify-content:space-around;align-items:center;flex-wrap:wrap;gap:30px}
.cert{text-align:center}
.cert .badge-circle{width:80px;height:80px;border-radius:50%;border:2px solid var(--teal-400);display:flex;align-items:center;justify-content:center;margin:0 auto 12px;font-weight:800;color:var(--teal-300);font-size:14px}
.cert .cert-name{font-size:14px;color:#B8C5D6}

/* ============================================
   NEWS CARDS
   ============================================ */
.news{background:var(--bg-light)}
.news-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:24px}
.news-card{background:#fff;border-radius:var(--radius-lg);overflow:hidden;box-shadow:var(--shadow-sm);display:block;transition:all .3s}
.news-card:hover{box-shadow:var(--shadow-md);transform:translateY(-4px)}
.news-img{height:180px;background:linear-gradient(135deg,var(--navy-600),var(--teal-500));display:flex;align-items:center;justify-content:center;color:rgba(255,255,255,.3);font-size:40px}
.news-img img{width:100%;height:100%;object-fit:cover}
.news-body{padding:22px}
.news-body .date{font-size:12px;color:var(--text-light);margin-bottom:8px}
.news-body h4{font-size:16px;font-weight:600;color:var(--navy-800);margin-bottom:8px;line-height:1.4}
.news-body p{font-size:13px;color:var(--text-muted)}

/* ============================================
   CTA BAND
   ============================================ */
.cta-band{background:linear-gradient(135deg,var(--teal-500),var(--navy-700));padding:70px 0;color:#fff;text-align:center}
.cta-band h2{font-size:30px;font-weight:800;margin-bottom:12px}
.cta-band p{color:rgba(255,255,255,.8);margin-bottom:28px;font-size:16px}
.btn-white{background:#fff;color:var(--navy-800);padding:14px 40px;border-radius:6px;font-weight:700;display:inline-block;transition:all .2s}
.btn-white:hover{transform:translateY(-2px);box-shadow:0 8px 24px rgba(0,0,0,.2);color:var(--navy-800)}

/* ============================================
   PAGE HERO (sub pages)
   ============================================ */
.page-hero{background:linear-gradient(135deg,var(--navy-900),var(--navy-700));color:#fff;padding:60px 0;text-align:center}
.page-hero h1{font-size:36px;font-weight:800;margin-bottom:10px}
.page-hero .breadcrumb{font-size:14px;color:#94A3B8}
.page-hero .breadcrumb a{color:var(--teal-300)}

/* ============================================
   FILTER BAR
   ============================================ */
.filter-bar{background:#fff;padding:20px 0;box-shadow:var(--shadow-sm);position:sticky;top:80px;z-index:50}
.filter-bar .container{display:flex;gap:12px;align-items:center;flex-wrap:wrap}
.filter-chip{padding:8px 20px;border-radius:20px;font-size:14px;background:var(--bg-light);color:var(--text-muted);transition:all .2s;border:1px solid transparent}
.filter-chip:hover{border-color:var(--teal-500);color:var(--teal-500)}
.filter-chip.active{background:var(--teal-500);color:#fff}

/* ============================================
   PRODUCT DETAIL
   ============================================ */
.detail{padding:40px 0}
.detail-grid{display:grid;grid-template-columns:1fr 1fr;gap:40px;margin-bottom:50px}
.prod-visual{background:linear-gradient(135deg,var(--navy-800),var(--navy-900));border-radius:var(--radius-lg);padding:50px;display:flex;flex-direction:column;justify-content:center;min-height:380px;position:relative;overflow:hidden}
.prod-visual::before{content:"";position:absolute;right:-40px;bottom:-40px;width:200px;height:200px;border-radius:50%;background:rgba(20,184,166,.15)}
.prod-visual .cat{font-size:13px;color:var(--teal-300);letter-spacing:2px;margin-bottom:12px}
.prod-visual .p-name{font-size:28px;font-weight:800;color:#fff;margin-bottom:16px}
.prod-visual .p-formula{font-family:'Courier New',monospace;font-size:16px;color:var(--teal-300);padding:16px;background:rgba(11,31,58,.5);border-radius:8px;border-left:3px solid var(--teal-400)}
.prod-info .tag-row{display:flex;gap:8px;margin-bottom:16px;flex-wrap:wrap}
.prod-info .tag{padding:4px 14px;border-radius:14px;font-size:12px;font-weight:600}
.tag-hot{background:#FEE2E2;color:#DC2626}
.tag-cert{background:#D1FAE5;color:#059669}
.tag-excl{background:#FEF3C7;color:#D97706}
.prod-info h1{font-size:30px;font-weight:800;color:var(--navy-800);margin-bottom:8px}
.prod-info .code-big{font-size:14px;color:var(--teal-500);font-weight:600;letter-spacing:1px;margin-bottom:16px}
.prod-info>p{color:var(--text-muted);font-size:15px;margin-bottom:24px;line-height:1.8}
.prod-actions{display:flex;gap:12px;flex-wrap:wrap}

.spec-section{background:#fff;border-radius:var(--radius-lg);padding:36px;box-shadow:var(--shadow-sm);margin-bottom:30px}
.spec-section h2{font-size:20px;font-weight:700;color:var(--navy-800);margin-bottom:20px;padding-bottom:12px;border-bottom:2px solid var(--teal-500);display:inline-block}
.spec-table{width:100%;border-collapse:collapse}
.spec-table th{background:var(--bg-light);text-align:left;padding:12px 16px;font-size:13px;color:var(--text-muted);font-weight:600;border:1px solid var(--border)}
.spec-table td{padding:12px 16px;font-size:14px;border:1px solid var(--border)}
.spec-table tr:nth-child(even) td{background:var(--bg-light)}

.info-grid{display:grid;grid-template-columns:1fr 1fr;gap:30px;margin-bottom:30px}
.info-card{background:#fff;border-radius:var(--radius-lg);padding:30px;box-shadow:var(--shadow-sm)}
.info-card h3{font-size:17px;font-weight:700;color:var(--navy-800);margin-bottom:14px}
.info-card p,.info-card li{font-size:14px;color:var(--text-muted);line-height:1.8}
.info-card ul{padding-left:18px}
.info-card ul li{list-style:disc}

.related{margin-top:40px}
.related h2{font-size:22px;font-weight:800;color:var(--navy-800);margin-bottom:24px}
.related-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:20px}

/* ============================================
   SINGLE NEWS / ARTICLE
   ============================================ */
.article-wrap{background:#fff;border-radius:var(--radius-lg);box-shadow:var(--shadow-sm);padding:50px;max-width:860px;margin:40px auto}
.article-wrap .article-date{font-size:13px;color:var(--text-light);margin-bottom:12px}
.article-wrap h1{font-size:28px;font-weight:800;color:var(--navy-800);margin-bottom:24px;line-height:1.3}
.article-wrap .article-content{font-size:16px;color:var(--text-dark);line-height:1.9}
.article-wrap .article-content img{border-radius:var(--radius);margin:20px 0}
.article-wrap .article-content p{margin-bottom:16px}
.article-nav{display:flex;justify-content:space-between;margin-top:40px;padding-top:20px;border-top:1px solid var(--border);font-size:14px}
.article-nav a{color:var(--teal-500)}

/* ============================================
   PAGINATION
   ============================================ */
.pagination{display:flex;justify-content:center;gap:8px;margin:40px 0}
.pagination .page-numbers{padding:8px 16px;border-radius:6px;background:#fff;box-shadow:var(--shadow-sm);font-size:14px;color:var(--text-dark)}
.pagination .current{background:var(--teal-500);color:#fff}
.pagination a:hover{background:var(--teal-500);color:#fff}

/* ============================================
   FOOTER
   ============================================ */
.site-footer{background:var(--navy-900);color:#94A3B8;padding:60px 0 0;font-size:14px}
.footer-grid{display:grid;grid-template-columns:2fr 1fr 1fr 1.5fr;gap:40px;padding-bottom:40px}
.site-footer h4{color:#fff;font-size:15px;margin-bottom:18px;font-weight:600}
.site-footer ul li{margin-bottom:10px}
.site-footer ul li a:hover{color:var(--teal-300)}
.footer-brand .site-logo{margin-bottom:16px}
.footer-brand p{line-height:1.8}
.footer-bottom{border-top:1px solid rgba(255,255,255,.1);padding:20px 0;text-align:center;font-size:13px;color:#64748B}

/* ============================================
   PAGE CONTENT (generic)
   ============================================ */
.page-content{padding:60px 0}
.page-content .container{max-width:900px}
.page-content h2{font-size:26px;color:var(--navy-800);margin:24px 0 12px}
.page-content p{margin-bottom:16px;color:var(--text-muted);line-height:1.8}

/* ============================================
   RESPONSIVE — TABLET
   ============================================ */
@media (max-width:1024px){
  .hero .container{grid-template-columns:1fr;gap:40px}
  .hero h1{font-size:36px}
  .about .container{grid-template-columns:1fr;gap:40px}
  .cat-grid,.prod-grid,.news-grid{grid-template-columns:repeat(2,1fr)}
  .footer-grid{grid-template-columns:1fr 1fr}
  .detail-grid{grid-template-columns:1fr}
  .info-grid{grid-template-columns:1fr}
  .related-grid{grid-template-columns:repeat(2,1fr)}
}

/* ============================================
   CONTACT PAGE
   ============================================ */
.contact-grid input:focus,.contact-grid textarea:focus,.contact-grid select:focus{
  outline:2px solid var(--teal-400);border-color:var(--teal-400)
}

/* ============================================
   RESPONSIVE — MOBILE
   ============================================ */
@media (max-width:768px){
  .contact-grid{grid-template-columns:1fr !important}
  .topbar .container{justify-content:center;text-align:center}
  .topbar .contact-info span{display:block;margin-right:0;margin-bottom:4px}
  .menu-toggle{display:flex}
  .main-nav{display:none;position:absolute;top:80px;left:0;right:0;background:#fff;box-shadow:var(--shadow-md);padding:16px}
  .main-nav.open{display:block}
  .main-nav ul{flex-direction:column;align-items:stretch;gap:0}
  .main-nav>ul>li>a{padding:14px 20px;border-bottom:1px solid var(--border)}
  .main-nav ul ul{position:static;box-shadow:none;padding-left:20px}
  .header-cta{display:none}
  .hero{padding:60px 0 80px}
  .hero h1{font-size:28px}
  .hero p{font-size:15px}
  .stats{margin-top:-40px;padding:24px 0}
  .stats .container{grid-template-columns:repeat(2,1fr);gap:20px}
  .stat{border-right:none;border-bottom:1px solid var(--border);padding-bottom:16px}
  .stat:nth-last-child(-n+2){border-bottom:none;padding-bottom:0}
  section{padding:50px 0}
  .section-title{font-size:24px}
  .cat-grid,.prod-grid,.news-grid{grid-template-columns:1fr}
  .footer-grid{grid-template-columns:1fr}
  .detail-grid{grid-template-columns:1fr}
  .info-grid{grid-template-columns:1fr}
  .related-grid{grid-template-columns:1fr}
  .article-wrap{padding:24px;margin:20px}
  .page-hero h1{font-size:26px}
  .filter-bar{position:static}
  .prod-visual{padding:30px;min-height:280px}
}