/* 军凯电采暖 · cn.sdjunkai.cn 零依赖 */
:root{--warm:#b3401f;--warm-d:#8c2f14;--warm-l:#fdf0ea;--warm-2:#e0603a;--ink:#2c211c;--muted:#7d6b63;--line:#f0e2db;--bg:#fdfaf8;--card:#ffffff;--radius:14px;--shadow:0 6px 24px rgba(150,60,30,.08)}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{font-family:"PingFang SC","Microsoft YaHei","Source Han Sans SC",system-ui,-apple-system,sans-serif;color:var(--ink);background:var(--bg);line-height:1.75}
img{max-width:100%;height:auto;display:block}
a{color:var(--warm);text-decoration:none}
.wrap{max-width:1160px;margin:0 auto;padding:0 20px}
/* header */
.site-header{position:sticky;top:0;z-index:50;background:rgba(255,255,255,.94);backdrop-filter:blur(6px);border-bottom:1px solid var(--line)}
.nav-row{display:flex;align-items:center;justify-content:space-between;height:64px}
.brand{display:flex;align-items:center;gap:10px;color:var(--ink)}
.brand-badge{width:38px;height:38px;border-radius:10px;background:linear-gradient(135deg,var(--warm),var(--warm-2));color:#fff;font-weight:700;font-size:20px;display:flex;align-items:center;justify-content:center}
.brand-txt{display:flex;flex-direction:column;line-height:1.2}
.brand-txt b{font-size:18px;letter-spacing:2px}
.brand-txt i{font-style:normal;font-size:11px;color:var(--muted);letter-spacing:1px}
.nav{display:flex;align-items:center;gap:24px}
.nav a{color:var(--ink);font-size:15px}
.nav a:hover{color:var(--warm)}
.nav-tel{background:var(--warm);color:#fff!important;padding:7px 16px;border-radius:20px;font-weight:600}
.nav-btn{display:none;background:none;border:0;cursor:pointer;padding:8px}
.nav-btn span{display:block;width:22px;height:2px;background:var(--ink);margin:5px 0;border-radius:2px}
/* hero */
.hero{background:linear-gradient(120deg,#5e1f0e 0%,#b3401f 55%,#e0603a 100%);color:#fff;padding:88px 0 96px;position:relative;overflow:hidden}
.hero::after{content:"";position:absolute;right:-120px;top:-120px;width:420px;height:420px;border-radius:50%;background:rgba(255,255,255,.07)}
.hero h1{font-size:38px;line-height:1.3;letter-spacing:1px;max-width:640px}
.hero p.sub{margin-top:16px;font-size:17px;opacity:.92;max-width:620px}
.hero .hero-cta{margin-top:32px;display:flex;gap:14px;flex-wrap:wrap}
.btn{display:inline-block;padding:12px 28px;border-radius:26px;font-size:15px;font-weight:600}
.btn-light{background:#fff;color:var(--warm-d)}
.btn-ghost{border:1px solid rgba(255,255,255,.65);color:#fff}
.hero-tags{margin-top:40px;display:flex;gap:10px;flex-wrap:wrap}
.hero-tags span{background:rgba(255,255,255,.14);border:1px solid rgba(255,255,255,.25);padding:6px 14px;border-radius:18px;font-size:13px}
/* sections */
section{padding:64px 0}
.sec-head{text-align:center;margin-bottom:40px}
.sec-head h2{font-size:28px;color:var(--warm-d)}
.sec-head p{color:var(--muted);margin-top:8px}
.alt{background:#fff}
/* cards */
.grid{display:grid;gap:22px}
.g3{grid-template-columns:repeat(3,1fr)}
.g2{grid-template-columns:repeat(2,1fr)}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow);transition:transform .2s}
.card:hover{transform:translateY(-4px)}
/* cover 是 <a>，必须显式块化，否则 aspect-ratio 不生效，
   容器会被 img 的 height:100% 撑成纵向，cover 裁掉图内两侧文字 */
.card .cover{display:block;aspect-ratio:4/3;background:var(--warm-l);overflow:hidden}
.card .cover img{width:100%;height:100%;object-fit:contain;transition:transform .35s}
.card:hover .cover img{transform:scale(1.05)}
.card .body{padding:18px 20px 22px}
.card h3{font-size:17px;color:var(--ink)}
.card .tag{display:inline-block;font-size:12px;color:var(--warm);background:var(--warm-l);padding:2px 10px;border-radius:12px;margin-bottom:8px}
.card p{font-size:14px;color:var(--muted);margin-top:8px}
.card .more{display:inline-block;margin-top:12px;font-size:14px;font-weight:600}
/* feature list */
.feats{display:grid;grid-template-columns:repeat(4,1fr);gap:20px}
.feat{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:26px 22px;text-align:center}
.feat .ic{width:54px;height:54px;margin:0 auto 14px;border-radius:14px;background:var(--warm-l);display:flex;align-items:center;justify-content:center;font-size:26px}
.feat h3{font-size:16px}
.feat p{font-size:13.5px;color:var(--muted);margin-top:8px;text-align:left}
/* steps */
.steps{counter-reset:s;max-width:860px;margin:0 auto}
.step{display:flex;gap:18px;padding:18px 0;border-bottom:1px dashed var(--line)}
.step:last-child{border-bottom:0}
.step b.no{flex:0 0 40px;height:40px;border-radius:50%;background:var(--warm);color:#fff;display:flex;align-items:center;justify-content:center;font-size:17px}
.step h3{font-size:16px}
.step p{font-size:14px;color:var(--muted)}
/* rich text */
.rich{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:34px 38px;box-shadow:var(--shadow)}
.rich p{margin:12px 0;font-size:15.5px;color:#3b2c25}
.rich img{margin:18px auto;border-radius:10px}
.rich strong,.rich b{color:var(--warm-d)}
.rich h2,.rich h3{color:var(--warm-d)}
/* hero 双栏 */
.hero-grid{display:grid;grid-template-columns:1.05fr .95fr;gap:44px;align-items:center}
.hero-visual{position:relative}
.hero-visual img{width:100%;aspect-ratio:16/10;object-fit:cover;border-radius:16px;box-shadow:0 24px 60px rgba(0,0,0,.32);border:1px solid rgba(255,255,255,.28)}
.hero-visual::after{content:"";position:absolute;right:-14px;bottom:-14px;width:120px;height:120px;border-radius:20px;background:rgba(255,255,255,.12)}
/* 产品详情 */
.prod-head{display:flex;align-items:center;gap:12px;flex-wrap:wrap;margin-bottom:18px}
.prod-head h2{font-size:22px;color:var(--warm-d)}
.album{display:grid;grid-template-columns:repeat(auto-fill,minmax(250px,1fr));gap:14px;margin-bottom:26px}
.ph{margin:0;background:#fff;border:1px solid var(--line);border-radius:12px;overflow:hidden;box-shadow:var(--shadow)}
.ph .im{display:block;aspect-ratio:4/3;overflow:hidden;background:var(--warm-l)}
.ph img{width:100%;height:100%;object-fit:cover;transition:transform .35s}
.ph:hover img{transform:scale(1.04)}
.ph figcaption{font-size:12.5px;color:var(--muted);padding:8px 12px;border-top:1px solid var(--line);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.article{max-width:880px;background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:30px 34px;box-shadow:var(--shadow)}
.article p{margin:10px 0;font-size:15.5px;color:#3b2c25;text-align:justify}
.article strong,.article b{color:var(--warm-d)}
/* 图文交替行 —— 图片侧略宽（1.06:1），配图更醒目、文字行宽更舒适 */
.media-row{display:grid;grid-template-columns:1.06fr 1fr;gap:32px;align-items:center;margin:0 0 34px}
.media-row.rev .media-img{order:2}
.media-img{display:grid;gap:12px;align-content:center}
.media-img.two{grid-template-columns:1fr 1fr}
/* 配图统一用 contain：宁可留白，不裁产品。
   4:3 与更宽的图会被容器自然填满（contain==cover 效果一致）；
   略窄的图（ratio 1.20~1.31）左右出极窄留白，视觉上几乎不可见。 */
.media-img img{width:100%;aspect-ratio:4/3;object-fit:contain;border-radius:12px;
  border:1px solid var(--line);box-shadow:var(--shadow);transition:transform .3s;
  background:var(--warm-l);box-sizing:border-box;padding:8px 10px}
/* 竖构图（ratio < 1.20，如 554x801 / 553x738 / 448x512）：
   取消固定比例，按自身比例完整显示 —— 主体一刀不裁。
   撑满所在栏宽（与同行横图等宽，观感平衡），高度由自身比例推出。 */
.media-img img.tall{aspect-ratio:auto;width:100%;height:auto;max-width:100%;
  max-height:560px;object-fit:contain;padding:0;background:transparent;
  justify-self:stretch;align-self:center}
/* 两列并排时：竖图同样撑满栏宽，只压高度上限，避免整行被拉爆 */
.media-img.two img.tall{width:100%;max-height:420px;object-fit:contain}
/* 纯图组里的竖图 */
.media-row.pure.two .media-img img.tall{width:100%;max-height:380px}
.media-img img:hover{transform:scale(1.02)}
.media-txt p{margin:0 0 13px;font-size:15.5px;color:#3b2c25;text-align:justify;
  line-height:1.85;letter-spacing:.1px}
.media-txt p:last-child{margin-bottom:0}
.media-txt strong,.media-txt b{color:var(--warm-d)}
/* 单图整宽：不参与左右交替，避免半屏留白 */
.media-row.wide{grid-template-columns:1fr;gap:0}
.media-row.wide .media-img img{aspect-ratio:16/9}
/* 纯图组：两列紧凑并排 */
.media-row.pure.two{grid-template-columns:1fr;gap:14px;margin-bottom:30px}
.media-row.pure.two .media-img.two{gap:14px}
/* 段间小标题（由语义切分产生的短行）微调 */
.media-txt p:first-child{color:#2a1e19}
.back{margin-top:14px;font-size:14px}
/* product sections */
.prod-sec{padding-top:30px}
.prod-anchor{scroll-margin-top:110px}
.cat-line{font-size:13px;color:var(--warm);font-weight:600;letter-spacing:2px;margin:34px 0 6px}
.cat-tabs{position:sticky;top:64px;z-index:40;background:rgba(255,255,255,.97);backdrop-filter:blur(6px);border-bottom:1px solid var(--line);margin-bottom:36px}
.cat-tabs .wrap{display:flex;gap:10px;overflow-x:auto;padding:12px 20px;-webkit-overflow-scrolling:touch}
.cat-tabs a{flex:0 0 auto;font-size:14px;color:var(--ink);padding:8px 18px;border-radius:20px;border:1px solid var(--line);background:#fff;white-space:nowrap}
.cat-tabs a:hover{color:var(--warm);border-color:var(--warm)}
.cat-sec{padding:56px 0}
.cat-sec .sec-head{margin-bottom:32px;position:relative}
.cat-no{position:absolute;left:50%;top:-26px;transform:translateX(-50%);font-size:46px;font-weight:700;color:var(--warm-l);line-height:1;pointer-events:none}
.cat-sec .sec-head h2{position:relative}
.cat-sec .prod-sec{background:#fff;border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow);padding:26px 28px;margin-bottom:22px}
/* 常见问题 */
.faq-list{display:grid;gap:12px;max-width:900px;margin:0 auto}
.faq-item{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:0 20px;box-shadow:var(--shadow)}
.faq-item summary{cursor:pointer;list-style:none;padding:16px 0;font-size:16px;font-weight:500;color:var(--ink);position:relative;padding-right:28px}
.faq-item summary::-webkit-details-marker{display:none}
.faq-item summary::after{content:"+";position:absolute;right:0;top:50%;transform:translateY(-50%);font-size:20px;color:var(--warm);font-weight:400;line-height:1}
.faq-item[open] summary::after{content:"−"}
.faq-a{padding:0 0 16px;border-top:1px solid var(--line);margin-top:-1px}
.faq-a p{margin:14px 0 0;font-size:15px;color:#3b2c25;text-align:justify;line-height:1.8}
/* cta */
.cta{background:linear-gradient(120deg,var(--warm-d),var(--warm));color:#fff;border-radius:var(--radius);padding:44px 40px;display:flex;justify-content:space-between;align-items:center;gap:20px;flex-wrap:wrap}
.cta h2{font-size:24px}
.cta p{opacity:.9;margin-top:6px}
.cta .btn{background:#fff;color:var(--warm-d)}
/* contact */
.contact-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:22px}
.contact-card{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:30px;text-align:center}
.contact-card .ic{font-size:30px}
.contact-card h3{margin-top:10px;font-size:16px}
.contact-card p{margin-top:8px;color:var(--muted);font-size:14.5px;word-break:break-all}
/* breadcrumb */
.crumb{font-size:13px;color:var(--muted);padding:18px 0 0}
.crumb a{color:var(--muted)}
/* page header */
.phead{background:var(--warm-l);padding:46px 0;margin-bottom:40px}
.phead h1{font-size:28px;color:var(--warm-d)}
.phead p{color:var(--muted);margin-top:6px}
/* 选型表 */
.tbl{width:100%;border-collapse:collapse;background:#fff;box-shadow:var(--shadow);border-radius:var(--radius);overflow:hidden;font-size:14.5px}
.tbl th,.tbl td{padding:12px 14px;border-bottom:1px solid var(--line);text-align:left;vertical-align:top}
.tbl th{background:var(--warm-l);color:var(--warm-d);font-weight:600;white-space:nowrap}
.tbl tr:last-child td{border-bottom:0}
.tbl-scroll{overflow-x:auto;-webkit-overflow-scrolling:touch}
/* footer */
.site-footer{background:#2a1a14;color:#e0cfc7;margin-top:70px}
.foot-grid{display:grid;grid-template-columns:1.4fr 1fr 1.2fr;gap:34px;padding:48px 20px 36px}
.foot-grid h4{color:#fff;font-size:16px;margin-bottom:10px}
.foot-grid p{font-size:13.5px;line-height:1.9}
.foot-grid a{color:#e0cfc7}
.foot-bar{border-top:1px solid rgba(255,255,255,.12);padding:16px 0;font-size:12.5px}
.foot-bar a{color:#e0cfc7}
/* responsive */
@media (max-width:900px){
 .g3{grid-template-columns:repeat(2,1fr)}
 .feats{grid-template-columns:repeat(2,1fr)}
 .foot-grid{grid-template-columns:1fr;gap:22px}
 .hero h1{font-size:30px}
 .hero-grid{grid-template-columns:1fr;gap:30px}
 .hero-visual{order:-1}
 /* 平板：图文行收窄间距，图片侧仍略宽 */
 .media-row{gap:22px;margin-bottom:28px}
 .media-txt p{font-size:15px;line-height:1.8}
}
@media (max-width:640px){
 .nav{display:none;position:absolute;top:64px;left:0;right:0;background:#fff;flex-direction:column;padding:18px 24px;gap:16px;border-bottom:1px solid var(--line);align-items:flex-start}
 .nav.open{display:flex}
 .nav-btn{display:block}
 .g3,.g2,.feats,.contact-grid{grid-template-columns:1fr}
 section{padding:46px 0}
 .hero{padding:60px 0 70px}
 .rich,.article{padding:22px 18px}
 /* 手机：图文改上下堆叠，图在上；两图并排仍保留 */
 .media-row{grid-template-columns:1fr;gap:14px;margin-bottom:24px}
 .media-row.rev .media-img{order:0}
 .media-row.pure.two{gap:10px;margin-bottom:22px}
 .media-row.pure.two .media-img.two{gap:10px}
 .media-row.wide .media-img img{aspect-ratio:16/10}
 /* 手机端竖图同样不裁切：保持自身比例、撑满栏宽、放开高度上限 */
 .media-img img.tall{aspect-ratio:auto;width:100%;max-width:100%;height:auto;max-height:none}
 .media-img.two img.tall{max-height:none}
 .media-txt p{font-size:15px;line-height:1.78;margin-bottom:11px}
 .cat-sec{padding:44px 0}
 .cat-sec .prod-sec{padding:20px 16px}
 .cat-no{font-size:36px;top:-20px}
}