/* ============ OhYeahSolar 公共样式 ============ */
:root{
  --navy:#0B2545; --navy-2:#13315C;
  --green:#2E9E4F; --green-l:#4CAF50;
  --orange:#F7941D; --red:#E8442E; --blue:#1E6FBA;
  --ink:#1a2a3a; --muted:#5b6b7b; --bg:#f6f9f6; --white:#fff;
  --grad:linear-gradient(135deg,#2E9E4F 0%,#F7941D 55%,#E8442E 100%);
  --grad-soft:linear-gradient(135deg,rgba(46,158,79,.12),rgba(247,148,29,.12));
  --shadow-sm:0 4px 14px rgba(11,37,69,.08);
  --shadow-md:0 12px 32px rgba(11,37,69,.12);
  --shadow-lg:0 24px 60px rgba(11,37,69,.18);
  --radius:18px;
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  font-family:"Segoe UI","PingFang SC","Microsoft YaHei","Helvetica Neue",Arial,"Be Vietnam Pro",sans-serif;
  color:var(--ink);background:var(--bg);line-height:1.7;overflow-x:hidden;
}
img{max-width:100%;display:block}
a{text-decoration:none;color:inherit}
.container{max-width:1240px;margin:0 auto;padding:0 28px}

/* 动画 */
.reveal{opacity:0;transform:translateY(36px);transition:opacity .9s cubic-bezier(.16,1,.3,1),transform .9s cubic-bezier(.16,1,.3,1)}
.reveal.in{opacity:1;transform:none}
.reveal-d1{transition-delay:.12s}.reveal-d2{transition-delay:.24s}
.reveal-d3{transition-delay:.36s}.reveal-d4{transition-delay:.48s}

.section-pad{padding:100px 0}
.eyebrow{display:inline-block;font-size:13px;letter-spacing:3px;font-weight:700;color:var(--green);text-transform:uppercase;margin-bottom:14px}
.eyebrow::before{content:"";display:inline-block;width:28px;height:2px;background:var(--grad);vertical-align:middle;margin-right:10px}
h2.sec-title{font-size:clamp(28px,4vw,42px);color:var(--navy);line-height:1.25;font-weight:800;margin-bottom:18px}
.sec-sub{color:var(--muted);font-size:16.5px;max-width:760px}
.center{text-align:center}.center .sec-sub{margin:0 auto}
.grad-text{background:linear-gradient(120deg,#2E9E4F,#F7941D,#E8442E);-webkit-background-clip:text;background-clip:text;color:transparent}

/* 按钮 */
.btn{display:inline-flex;align-items:center;gap:8px;padding:14px 30px;border-radius:999px;font-weight:600;font-size:15px;cursor:pointer;border:none;transition:all .3s;font-family:inherit}
.btn-primary{background:var(--grad);color:#fff;box-shadow:0 10px 30px rgba(247,148,29,.35)}
.btn-primary:hover{transform:translateY(-3px);box-shadow:0 16px 40px rgba(247,148,29,.5)}
.btn-ghost{background:rgba(255,255,255,.1);color:#fff;border:1px solid rgba(255,255,255,.3);backdrop-filter:blur(8px)}
.btn-ghost:hover{background:rgba(255,255,255,.2);transform:translateY(-3px)}
.btn-dark{background:var(--navy);color:#fff}
.btn-dark:hover{background:var(--navy-2);transform:translateY(-3px)}

/* 导航（通用） */
.nav{position:fixed;top:0;left:0;right:0;z-index:100;padding:16px 0;transition:all .35s ease}
.nav.scrolled{background:rgba(255,255,255,.9);backdrop-filter:blur(14px);box-shadow:0 2px 20px rgba(11,37,69,.08);padding:10px 0}
.nav-inner{display:flex;align-items:center;justify-content:space-between}
.brand{display:flex;align-items:center;gap:12px}
.brand img{height:46px;width:auto;transition:height .3s}
.nav.scrolled .brand img{height:38px}
.brand-text{line-height:1.15}
.brand-text b{display:block;color:#fff;font-size:16px;transition:color .3s}
.nav.scrolled .brand-text b{color:var(--navy)}
.brand-text small{font-size:10px;letter-spacing:2px;color:rgba(255,255,255,.75);transition:color .3s}
.nav.scrolled .brand-text small{color:var(--muted)}
.nav-links{display:flex;gap:28px;align-items:center}
.nav-links a{color:rgba(255,255,255,.92);font-size:14.5px;font-weight:500;position:relative;transition:color .3s}
.nav.scrolled .nav-links a{color:var(--ink)}
.nav-links a::after{content:"";position:absolute;left:0;bottom:-6px;width:0;height:2px;background:var(--grad);transition:width .3s}
.nav-links a:hover::after{width:100%}
.lang-switch{display:flex;gap:0;border:1px solid rgba(255,255,255,.4);border-radius:999px;overflow:hidden}
.nav.scrolled .lang-switch{border-color:rgba(11,37,69,.2)}
.lang-switch button{background:transparent;border:none;color:#fff;padding:6px 14px;font-size:13px;cursor:pointer;font-weight:600;transition:all .3s;font-family:inherit}
.nav.scrolled .lang-switch button{color:var(--ink)}
.lang-switch button.active{background:var(--grad);color:#fff}

/* 返回按钮（详情页） */
.back-bar{position:fixed;top:0;left:0;right:0;z-index:101;padding:14px 28px;background:rgba(11,37,69,.85);backdrop-filter:blur(12px);display:flex;align-items:center;justify-content:space-between}
.back-bar a{color:#fff;display:inline-flex;align-items:center;gap:8px;font-size:14px;font-weight:600;transition:all .3s}
.back-bar a:hover{color:var(--orange)}
.back-bar .lang-switch{border-color:rgba(255,255,255,.3)}

/* 详情页 Hero */
.detail-hero{position:relative;min-height:52vh;display:flex;align-items:center;color:#fff;overflow:hidden;padding-top:70px}
.detail-hero .bg{position:absolute;inset:0;z-index:-2;background-size:cover;background-position:center}
.detail-hero::before{content:"";position:absolute;inset:0;z-index:-1;background:linear-gradient(120deg,rgba(11,37,69,.9),rgba(11,37,69,.6) 60%,rgba(20,60,40,.5))}
.detail-hero h1{font-size:clamp(32px,5vw,54px);font-weight:800;line-height:1.15;margin-bottom:18px}
.detail-hero p{font-size:clamp(15px,1.6vw,18px);color:rgba(255,255,255,.85);max-width:680px}

/* 卡片 */
.card{background:#fff;border-radius:var(--radius);padding:32px;box-shadow:var(--shadow-sm);transition:all .4s;border:1px solid rgba(11,37,69,.05)}
.card:hover{transform:translateY(-6px);box-shadow:var(--shadow-md)}

/* 流程步骤 */
.steps{display:grid;grid-template-columns:repeat(4,1fr);gap:20px;margin-top:40px}
.step{position:relative;padding:28px 22px;background:#fff;border-radius:14px;box-shadow:var(--shadow-sm);text-align:center}
.step .num{width:44px;height:44px;border-radius:50%;background:var(--grad);color:#fff;display:flex;align-items:center;justify-content:center;font-weight:800;margin:0 auto 14px}
.step h4{color:var(--navy);margin-bottom:8px;font-size:16px}
.step p{font-size:13.5px;color:var(--muted)}

/* 特性网格 */
.feature-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:20px;margin-top:40px}
.feature{background:#fff;padding:28px;border-radius:14px;box-shadow:var(--shadow-sm);border-top:3px solid var(--green)}
.feature .ic{font-size:32px;margin-bottom:12px}
.feature h4{color:var(--navy);font-size:16px;margin-bottom:8px}
.feature p{font-size:13.5px;color:var(--muted)}

/* CTA */
.cta{padding:90px 0;text-align:center;color:#fff;position:relative;overflow:hidden;background:linear-gradient(135deg,#0B254F,#13315C 50%,#1a5f3a)}
.cta h2{font-size:clamp(26px,4vw,40px);margin-bottom:16px}
.cta p{color:rgba(255,255,255,.8);max-width:640px;margin:0 auto 32px}
.cta .contact-row{display:flex;gap:30px;justify-content:center;flex-wrap:wrap;margin-top:20px}
.cta .contact-item{display:flex;align-items:center;gap:10px;font-size:15px;color:#fff}
.cta .contact-item .ic{width:44px;height:44px;border-radius:50%;background:rgba(255,255,255,.15);display:flex;align-items:center;justify-content:center;font-size:18px}

/* Footer */
footer{background:#071a33;color:rgba(255,255,255,.7);padding:50px 0 24px;font-size:14px}
.foot-bottom{border-top:1px solid rgba(255,255,255,.1);padding-top:20px;text-align:center;font-size:12px;color:rgba(255,255,255,.4)}

/* 回到顶部 */
.to-top{position:fixed;right:28px;bottom:28px;width:48px;height:48px;border-radius:50%;background:var(--grad);color:#fff;display:flex;align-items:center;justify-content:center;cursor:pointer;opacity:0;pointer-events:none;transition:all .3s;z-index:99;border:none;font-size:18px;box-shadow:0 8px 24px rgba(247,148,29,.4)}
.to-top.show{opacity:1;pointer-events:auto}

/* 案例页 */
.case-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:24px;margin-top:50px}
.case-card{background:#fff;border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow-sm);transition:all .4s;cursor:pointer}
.case-card:hover{transform:translateY(-8px);box-shadow:var(--shadow-lg)}
.case-card .ph{height:220px;overflow:hidden;position:relative}
.case-card .ph img{width:100%;height:100%;object-fit:cover;transition:transform .6s}
.case-card:hover .ph img{transform:scale(1.08)}
.case-card .bd{padding:20px}
.case-card .bd .city{font-size:12px;color:var(--green);font-weight:700;letter-spacing:2px}
.case-card .bd h3{font-size:17px;color:var(--navy);margin:6px 0}
.case-card .bd p{font-size:13px;color:var(--muted)}

/* 灯箱 */
.lightbox{position:fixed;inset:0;background:rgba(0,0,0,.9);z-index:200;display:none;align-items:center;justify-content:center;cursor:zoom-out}
.lightbox.open{display:flex}
.lightbox img{max-width:92%;max-height:90%;border-radius:8px}

/* 响应式 */
@media (max-width:960px){
  .nav-links{display:none}
  .steps{grid-template-columns:repeat(2,1fr)}
  .feature-grid{grid-template-columns:1fr}
  .case-grid{grid-template-columns:1fr}
}