/* ============================================================
   HELIOCORE · Solar Panel Manufacturer
   设计语言: 暖阳工程风 (Warm Solar Engineering / Light)
   暖白 #FBF9F4 / 硅片深蓝 #14284B / 阳光金 #E89B18
   整版 banner hero / feature 大卡 + 3 列 / 照片压字应用卡
   全站小圆角 1.2rem / 阴影染深蓝 / HarmonyOS Sans
   ============================================================ */

:root{
    --c-bg:#FBF9F4;
    --c-white:#FFFFFF;
    --c-navy:#14284B;
    --c-navy-deep:#0D1C37;
    --c-text:#5A6474;
    --c-gold:#E89B18;
    --c-gold-deep:#C77F0A;
    --c-line:#E6E1D5;
    --sh:0 1rem 2.8rem rgba(20,40,75,.10);
    --r:1.2rem;
    --font:'HarmonyOS Sans',system-ui,-apple-system,'Segoe UI',sans-serif;
    --shell:min(144rem,calc(100% - 8rem));
    --nav-h:7.6rem;
}

*{margin:0;padding:0;box-sizing:border-box;}
html{scroll-behavior:smooth;font-size:clamp(9px,0.6945vw,11px);}
body{font-family:var(--font);font-size:1.6rem;line-height:1.7;color:var(--c-text);background:var(--c-bg);-webkit-font-smoothing:antialiased;}
img{display:block;max-width:100%;}
a{text-decoration:none;color:inherit;}
button{font-family:inherit;border:none;background:none;cursor:pointer;}
section{scroll-margin-top:calc(var(--nav-h) + 1rem);}
h1,h2,h3{color:var(--c-navy);}
::selection{background:var(--c-gold);color:var(--c-navy-deep);}

.index_shell{width:var(--shell);margin:0 auto;}

/* ---------- 按钮 ---------- */
.index_btn{display:inline-flex;align-items:center;justify-content:center;gap:1rem;padding:1.5rem 3rem;font-size:1.4rem;font-weight:700;letter-spacing:.04em;line-height:1;border-radius:var(--r);transition:all .3s;white-space:nowrap;}
.index_btn--navy{background:var(--c-navy);color:#fff;}
.index_btn--navy:hover{background:var(--c-navy-deep);transform:translateY(-2px);box-shadow:var(--sh);}
.index_btn--gold{background:var(--c-gold);color:var(--c-navy-deep);}
.index_btn--gold:hover{background:var(--c-gold-deep);color:#fff;transform:translateY(-2px);}
.index_btn--ghost{border:1px solid rgba(255,255,255,.55);color:#fff;background:rgba(255,255,255,.06);}
.index_btn--ghost:hover{background:#fff;color:var(--c-navy);}

/* ---------- 顶栏 ---------- */
.index_bar{position:fixed;top:0;left:0;right:0;z-index:90;background:rgba(251,249,244,.92);backdrop-filter:blur(10px);border-bottom:1px solid var(--c-line);}
.index_bar-inner{height:var(--nav-h);display:flex;align-items:center;justify-content:space-between;gap:3rem;}
.index_brand{display:flex;align-items:center;gap:1.1rem;}
.index_brand-mark{width:3.4rem;height:3.4rem;border-radius:var(--r);background:var(--c-navy);color:var(--c-gold);display:grid;place-items:center;font-size:2rem;}
.index_brand-text{font-size:1.9rem;font-weight:900;letter-spacing:.2em;color:var(--c-navy);}
.index_bar-nav{display:flex;gap:3rem;}
.index_bar-nav a{font-size:1.4rem;font-weight:500;color:var(--c-text);padding:.5rem 0;transition:color .25s;}
.index_bar-nav a:hover{color:var(--c-navy);}
.index_bar-actions{display:flex;align-items:center;gap:1.8rem;}
.index_bar-actions .index_btn{padding:1.1rem 2.2rem;}
.index_burger{display:none;flex-direction:column;gap:.6rem;padding:.8rem;}
.index_burger span{width:2.4rem;height:2px;background:var(--c-navy);}

.index_drawer{position:fixed;inset:0;z-index:80;background:var(--c-bg);padding:12rem 8% 4rem;}
.index_drawer-nav{display:flex;flex-direction:column;gap:2.4rem;}
.index_drawer-nav a{font-size:2.4rem;font-weight:700;color:var(--c-navy);}
.index_drawer-nav .index_btn{margin-top:2rem;max-width:max-content;font-size:1.4rem;color:#fff;}

/* ---------- Hero: 整版 banner ---------- */
.index_hero{height:calc(100vh - var(--nav-h));min-height:56rem;margin-top:var(--nav-h);background:url('../images/index_banner_main.webp') center/cover no-repeat,var(--c-navy-deep);display:flex;align-items:center;}
.index_hero-copy{max-width:56rem;}
.index_hero-copy h1{font-size:4.8rem;line-height:1.12;font-weight:900;color:#fff;letter-spacing:-.01em;}
.index_hero-copy p{margin-top:2.2rem;font-size:1.65rem;line-height:1.7;color:rgba(255,255,255,.82);max-width:48rem;}
.index_hero-actions{margin-top:3.6rem;display:flex;gap:1.6rem;flex-wrap:wrap;}

/* ---------- 数据条 ---------- */
.index_strip{background:var(--c-white);border-bottom:1px solid var(--c-line);}
.index_strip-inner{display:grid;grid-template-columns:repeat(4,1fr);}
.index_strip-item{padding:3.2rem 3rem;border-left:1px solid var(--c-line);}
.index_strip-item:first-child{border-left:none;padding-left:0;}
.index_strip-item strong{display:block;font-size:3.2rem;font-weight:900;color:var(--c-navy);font-variant-numeric:tabular-nums;}
.index_strip-item strong span{color:var(--c-gold-deep);}
.index_strip-item>span{display:block;margin-top:.4rem;font-size:1.35rem;}

/* ---------- 章节 ---------- */
.index_sec{padding:10rem 0;}
.index_sec--white{background:var(--c-white);border-top:1px solid var(--c-line);border-bottom:1px solid var(--c-line);}
.index_head{margin-bottom:5.2rem;max-width:72rem;}
.index_head h2{font-size:3.8rem;line-height:1.15;font-weight:900;}
.index_head p{margin-top:1.6rem;font-size:1.55rem;}

.index_link{display:inline-flex;align-items:center;gap:.8rem;font-size:1.4rem;font-weight:700;color:var(--c-navy);transition:color .25s;}
.index_link:hover{color:var(--c-gold-deep);}
.index_link i{transition:transform .25s;}
.index_link:hover i{transform:translateX(.4rem);}

/* ---------- 01 产品: feature 大卡 + 3 列 ---------- */
.index_feature{display:grid;grid-template-columns:1.05fr 1fr;background:var(--c-white);border:1px solid var(--c-line);border-radius:var(--r);overflow:hidden;box-shadow:var(--sh);}
.index_feature-media img{width:100%;height:100%;object-fit:cover;aspect-ratio:4/3;}
.index_feature-body{padding:4.6rem 4.8rem;display:flex;flex-direction:column;justify-content:center;}
.index_feature-body h3{font-size:2.6rem;font-weight:900;line-height:1.2;}
.index_feature-body>p{margin-top:1.6rem;font-size:1.5rem;}
.index_feature-specs{list-style:none;margin-top:2.8rem;display:grid;grid-template-columns:repeat(3,1fr);gap:2rem;padding-top:2.4rem;border-top:1px solid var(--c-line);}
.index_feature-specs strong{display:block;font-size:2rem;font-weight:900;color:var(--c-gold-deep);font-variant-numeric:tabular-nums;}
.index_feature-specs span{display:block;margin-top:.3rem;font-size:1.25rem;}
.index_feature-body .index_link{margin-top:3rem;}

.index_prod-grid{margin-top:2.8rem;display:grid;grid-template-columns:repeat(3,1fr);gap:2.8rem;}
.index_prod{background:var(--c-white);border:1px solid var(--c-line);border-radius:var(--r);overflow:hidden;transition:transform .3s,box-shadow .3s;}
.index_prod:hover{transform:translateY(-.5rem);box-shadow:var(--sh);}
.index_prod figure{overflow:hidden;}
.index_prod img{width:100%;aspect-ratio:4/3;object-fit:cover;transition:transform .6s;}
.index_prod:hover img{transform:scale(1.05);}
.index_prod-body{padding:2.6rem 2.8rem 3rem;}
.index_prod-body h3{font-size:1.9rem;font-weight:700;}
.index_prod-body p{margin-top:1rem;font-size:1.4rem;}
.index_prod-body .index_link{margin-top:1.8rem;}

/* ---------- 02 技术分栏 ---------- */
.index_tech{display:grid;grid-template-columns:1fr 1fr;gap:6.4rem;align-items:center;}
.index_tech-media{border-radius:var(--r);overflow:hidden;box-shadow:var(--sh);}
.index_tech-media img{width:100%;aspect-ratio:4/3;object-fit:cover;}
.index_tech-body .index_head{margin-bottom:2rem;}
.index_tech-text{font-size:1.55rem;}
.index_tech-list{margin-top:3rem;display:grid;gap:0;}
.index_tech-list div{display:flex;justify-content:space-between;gap:2.4rem;padding:1.6rem 0;border-top:1px solid var(--c-line);}
.index_tech-list div:last-child{border-bottom:1px solid var(--c-line);}
.index_tech-list dt{font-size:1.45rem;}
.index_tech-list dd{font-size:1.45rem;font-weight:700;color:var(--c-navy);text-align:right;font-variant-numeric:tabular-nums;}
.index_tech-body .index_btn{margin-top:3.2rem;}

/* ---------- 03 应用: 照片压字卡 ---------- */
.index_app-grid{display:grid;grid-template-columns:1fr 1fr;gap:2.8rem;}
.index_app{position:relative;border-radius:var(--r);overflow:hidden;display:block;box-shadow:var(--sh);}
.index_app img{width:100%;aspect-ratio:16/10;object-fit:cover;transition:transform .6s;}
.index_app:hover img{transform:scale(1.04);}
.index_app-cap{position:absolute;inset:auto 0 0 0;padding:6rem 3rem 2.6rem;background:linear-gradient(to top,rgba(13,28,55,.88) 30%,transparent);}
.index_app-cap h3{font-size:2.1rem;font-weight:700;color:#fff;}
.index_app-cap p{margin-top:.6rem;font-size:1.4rem;color:rgba(255,255,255,.8);max-width:44rem;}

/* ---------- 04 工厂 ---------- */
.index_factory{display:grid;grid-template-columns:1fr 1.1fr;gap:6.4rem;align-items:center;}
.index_factory-body>p{font-size:1.55rem;}
.index_factory-body .index_head{margin-bottom:2rem;}
.index_factory-facts{list-style:none;margin-top:3rem;display:grid;grid-template-columns:1fr 1fr;gap:2.4rem;}
.index_factory-facts strong{display:block;font-size:2.4rem;font-weight:900;color:var(--c-navy);font-variant-numeric:tabular-nums;}
.index_factory-facts span{display:block;margin-top:.3rem;font-size:1.3rem;}
.index_factory-body .index_btn{margin-top:3.4rem;}
.index_factory-media{position:relative;padding-bottom:6rem;}
.index_factory-main{border-radius:var(--r);overflow:hidden;box-shadow:var(--sh);}
.index_factory-main img{width:100%;aspect-ratio:4/3;object-fit:cover;}
.index_factory-sub{position:absolute;right:-2rem;bottom:0;width:44%;border:6px solid var(--c-white);border-radius:var(--r);overflow:hidden;box-shadow:var(--sh);}
.index_factory-sub img{width:100%;aspect-ratio:4/3;object-fit:cover;}

/* ---------- 05 质保横条 ---------- */
.index_warranty{background:url('../images/index_bg_cells.webp') center/cover no-repeat,var(--c-bg);}
.index_warranty .index_head{margin-bottom:4.4rem;}
.index_warranty-row{display:grid;grid-template-columns:repeat(3,1fr);gap:2.8rem;}
.index_warranty-item{background:var(--c-white);border:1px solid var(--c-line);border-radius:var(--r);padding:3.4rem 3.2rem;box-shadow:var(--sh);}
.index_warranty-item strong{display:block;font-size:4.2rem;font-weight:900;color:var(--c-gold-deep);font-variant-numeric:tabular-nums;line-height:1;}
.index_warranty-item span{display:block;margin-top:1.2rem;font-size:1.45rem;}

/* ---------- 06 案例 ---------- */
.index_case-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:2.8rem;}
.index_case{background:var(--c-white);border:1px solid var(--c-line);border-radius:var(--r);overflow:hidden;transition:transform .3s,box-shadow .3s;}
.index_case:hover{transform:translateY(-.5rem);box-shadow:var(--sh);}
.index_case figure{overflow:hidden;}
.index_case img{width:100%;aspect-ratio:3/2;object-fit:cover;transition:transform .6s;}
.index_case:hover img{transform:scale(1.05);}
.index_case-body{padding:2.6rem 2.8rem 3rem;}
.index_case-body h3{font-size:1.85rem;font-weight:700;line-height:1.3;}
.index_case-body p{margin-top:1rem;font-size:1.4rem;}

/* ---------- 07 FAQ ---------- */
.index_faq-item{background:var(--c-white);border:1px solid var(--c-line);border-radius:var(--r);margin-bottom:1.4rem;overflow:hidden;}
.index_faq-item summary{display:flex;align-items:center;justify-content:space-between;gap:2rem;padding:2.2rem 2.8rem;cursor:pointer;list-style:none;}
.index_faq-item summary::-webkit-details-marker{display:none;}
.index_faq-item summary h3{font-size:1.75rem;font-weight:700;}
.index_faq-item summary i{color:var(--c-gold-deep);font-size:1.9rem;transition:transform .3s;flex-shrink:0;}
.index_faq-item[open]{border-color:var(--c-gold);}
.index_faq-item[open] summary i{transform:rotate(45deg);}
.index_faq-item p{padding:0 2.8rem 2.4rem;font-size:1.45rem;max-width:78rem;}

/* ---------- 08 询盘: 暮色底 ---------- */
.index_contact{padding:10rem 0;background:url('../images/index_bg_cta_dark.webp') center/cover no-repeat,var(--c-navy-deep);}
.index_contact-grid{display:grid;grid-template-columns:1fr 1.1fr;gap:7rem;align-items:center;}
.index_contact-copy h2{font-size:3.8rem;font-weight:900;line-height:1.15;color:#fff;}
.index_contact-copy>p{margin-top:2rem;font-size:1.55rem;color:rgba(255,255,255,.8);}
.index_contact-list{list-style:none;margin-top:3.2rem;display:grid;gap:1.4rem;}
.index_contact-list li{display:flex;align-items:center;gap:1.4rem;font-size:1.55rem;color:rgba(255,255,255,.9);}
.index_contact-list i{color:var(--c-gold);font-size:1.9rem;}
.index_form{display:grid;gap:2rem;background:var(--c-white);border-radius:var(--r);padding:4rem;box-shadow:0 2rem 5rem rgba(0,0,0,.28);}
.index_form-row{display:grid;grid-template-columns:1fr 1fr;gap:2rem;}
.index_form label{display:grid;gap:.8rem;font-size:1.3rem;font-weight:600;color:var(--c-navy);}
.index_form input,.index_form textarea{border:1px solid var(--c-line);background:var(--c-bg);padding:1.3rem 1.6rem;font-family:var(--font);font-size:1.5rem;color:var(--c-navy);border-radius:calc(var(--r) - .4rem);transition:border-color .3s;}
.index_form input:focus,.index_form textarea:focus{outline:none;border-color:var(--c-gold);background:var(--c-white);}
.index_form textarea{resize:vertical;}
.index_form .index_btn{justify-self:start;margin-top:.6rem;}
.index_form-note{font-size:1.4rem;font-weight:600;color:#1D7A3F;}

/* ---------- Footer ---------- */
.index_footer{background:var(--c-navy-deep);color:rgba(255,255,255,.72);}
.index_footer .index_brand-mark{background:var(--c-gold);color:var(--c-navy-deep);}
.index_footer .index_brand-text{color:#fff;}
.index_footer-top{display:grid;grid-template-columns:1.4fr 1fr 1fr 1fr;gap:5rem;padding:7rem 0 5rem;}
.index_footer-brand p{margin-top:2rem;font-size:1.4rem;max-width:34rem;}
.index_footer-title{font-size:1.3rem;letter-spacing:.16em;text-transform:uppercase;color:#fff;font-weight:700;margin-bottom:2rem;}
.index_footer-col{display:flex;flex-direction:column;gap:1.3rem;}
.index_footer-col a{font-size:1.45rem;display:flex;align-items:center;gap:1rem;transition:color .3s;}
.index_footer-col a:hover{color:#fff;}
.index_footer-col i{color:var(--c-gold);}
.index_footer-bar{border-top:1px solid rgba(255,255,255,.12);}
.index_footer-bar-inner{display:flex;justify-content:space-between;gap:2rem;padding:2.2rem 0;font-size:1.3rem;flex-wrap:wrap;}

/* ---------- Reveal ---------- */
.index_reveal{opacity:0;transform:translateY(2.4rem);transition:opacity .7s ease,transform .7s ease;}
.index_reveal.is-visible{opacity:1;transform:none;}
@media (prefers-reduced-motion:reduce){
    html{scroll-behavior:auto;}
    .index_reveal{opacity:1;transform:none;transition:none;}
    .index_prod,.index_case,.index_btn,.index_app img,.index_prod img,.index_case img{transition:none;}
}

/* ============ 平板 ============ */
@media (max-width:1100px){
    .index_bar-nav{display:none;}
    .index_burger{display:flex;}
    .index_hero-copy h1{font-size:4rem;}
    .index_strip-inner{grid-template-columns:1fr 1fr;}
    .index_strip-item{padding:2.4rem 2.4rem;}
    .index_strip-item:nth-child(odd){border-left:none;padding-left:0;}
    .index_feature{grid-template-columns:1fr;}
    .index_feature-media img{aspect-ratio:16/9;}
    .index_prod-grid,.index_case-grid{grid-template-columns:1fr;}
    .index_tech,.index_factory,.index_contact-grid{grid-template-columns:1fr;gap:4.5rem;}
    .index_app-grid{grid-template-columns:1fr;}
    .index_warranty-row{grid-template-columns:1fr;}
}

/* ============ 手机 ============ */
@media (max-width:768px){
    .index_shell{width:calc(100% - 4rem);}
    .index_bar-actions .index_btn{display:none;}
    .index_hero{min-height:0;height:auto;padding:10rem 0 7rem;}
    .index_hero-copy h1{font-size:3.2rem;}
    .index_sec{padding:7rem 0;}
    .index_head h2{font-size:2.8rem;}
    .index_strip-inner{grid-template-columns:1fr;}
    .index_strip-item{border-left:none;padding:1.8rem 0;border-top:1px solid var(--c-line);}
    .index_strip-item:first-child{border-top:none;}
    .index_feature-body{padding:3rem 2.4rem;}
    .index_feature-specs{grid-template-columns:1fr;gap:1.4rem;}
    .index_factory-sub{right:0;}
    .index_app-cap{padding:5rem 2.2rem 2.2rem;}
    .index_form{padding:2.6rem;}
    .index_form-row{grid-template-columns:1fr;}
    .index_contact-copy h2{font-size:2.8rem;}
    .index_footer-top{grid-template-columns:1fr;gap:3.4rem;padding:5rem 0 4rem;}
    .index_footer-bar-inner{flex-direction:column;align-items:flex-start;gap:.6rem;}
}