/* === Reset & Base === */
*,*::before,*::after{margin:0;padding:0;box-sizing:border-box}
:root{
  --bg:#0f1123;
  --bg-2:#151833;
  --bg-3:#1a1f3d;
  --surface:rgba(30,36,70,.5);
  --surface-2:rgba(38,45,90,.7);
  --indigo:#6366f1;
  --indigo-bright:#818cf8;
  --teal:#22d3ee;
  --blue:#60a5fa;
  --gold:#f6b73c;
  --gold-bright:#ffce6b;
  --text:#f2f0ff;
  --text-2:#c7c6e8;
  --text-3:#8a88ad;
  --border:rgba(99,102,241,.25);
  --border-2:rgba(99,102,241,.12);
  --radius:16px;
  --radius-sm:10px;
  --maxw:1200px;
}
html{scroll-behavior:smooth;font-size:16px}
body{
  font-family:'Noto Sans SC',sans-serif;
  background:var(--bg);color:var(--text);line-height:1.65;overflow-x:hidden;
}
img{display:block;max-width:100%;height:auto}
a{text-decoration:none;color:inherit}
button{cursor:pointer;border:none;background:none;color:inherit;font-family:inherit}
ul{list-style:none}
input,select,textarea{font-family:inherit;color:inherit}

/* === 背景音乐 === */
.bg-music-control{position:fixed;right:22px;bottom:22px;z-index:200}
.music-btn{
  width:52px;height:52px;border-radius:50%;background:var(--bg-3);border:1px solid var(--border);
  display:flex;align-items:center;justify-content:center;color:var(--indigo-bright);cursor:pointer;
  box-shadow:0 6px 20px rgba(0,0,0,.4);transition:all .3s;
}
.music-btn:hover{border-color:var(--indigo);transform:scale(1.06)}
.icon-pause{display:none}
.music-btn.playing .icon-music{display:none}
.music-btn.playing .icon-pause{display:block}
.music-btn.playing{background:linear-gradient(135deg,var(--indigo),#8b5cf6);color:#fff}

/* === Nav === */
#nav{
  position:fixed;top:0;left:0;width:100%;z-index:100;
  background:rgba(15,17,35,.88);backdrop-filter:blur(20px);-webkit-backdrop-filter:blur(20px);
  border-bottom:1px solid var(--border-2);transition:all .3s;
}
#nav.scrolled{background:rgba(15,17,35,.96);border-bottom-color:var(--border)}
.nav-inner{
  max-width:var(--maxw);margin:0 auto;display:flex;align-items:center;justify-content:space-between;padding:.8rem 2rem;
}
.logo{display:flex;align-items:center;gap:.6rem;font-weight:900;font-size:1.3rem}
.logo-mark{
  width:40px;height:40px;border-radius:10px;background:linear-gradient(135deg,var(--indigo),#8b5cf6);color:#fff;
  display:flex;align-items:center;justify-content:center;font-size:1.2rem;box-shadow:0 0 16px rgba(99,102,241,.4);
}
.logo-text{color:var(--text)}
.logo-accent{color:var(--teal)}
.nav-links{display:flex;align-items:center;gap:1.8rem}
.nav-links a{font-size:.9rem;color:var(--text-2);font-weight:500;transition:color .2s}
.nav-links a:hover{color:var(--indigo-bright)}
.nav-links a.active{color:var(--teal);font-weight:700}
.nav-cta{padding:.5rem 1.3rem;background:linear-gradient(135deg,var(--indigo),#8b5cf6);color:#fff!important;border-radius:40px;transition:all .25s}
.nav-cta:hover{box-shadow:0 4px 16px rgba(99,102,241,.4)}
.menu-toggle{display:none;color:var(--indigo-bright)}
.nav-mobile{display:none;flex-direction:column;padding:0 2rem;background:rgba(15,17,35,.96);border-bottom:1px solid var(--border)}
.nav-mobile a{padding:.8rem 0;color:var(--text-2);border-bottom:1px solid var(--border-2)}
.nav-mobile a:last-child{border-bottom:none}

/* === Section head === */
.section-head{max-width:var(--maxw);margin:0 auto;padding:4.5rem 2rem 2.5rem;text-align:center}
.section-tag{display:inline-block;font-size:.78rem;color:var(--teal);letter-spacing:.16em;margin-bottom:.8rem;font-weight:700;text-transform:uppercase}
.section-head h2{
  font-family:'Noto Serif SC',serif;font-weight:900;font-size:clamp(1.8rem,4.5vw,2.5rem);line-height:1.2;margin-bottom:1rem;
  background:linear-gradient(135deg,#f6d78a,#ffffff 50%,#b9bdca);-webkit-background-clip:text;background-clip:text;-webkit-text-fill-color:transparent;
}
.section-head .sub{color:var(--text-2);max-width:600px;margin:0 auto;font-weight:300}
.page-hero{
  position:relative;padding:7rem 2rem 3rem;text-align:center;background:
    radial-gradient(ellipse at 20% 30%,rgba(99,102,241,.18),transparent 50%),
    radial-gradient(ellipse at 80% 70%,rgba(34,211,238,.12),transparent 50%);
}
.page-hero{padding-top:8.5rem}
.page-hero h1{
  font-family:'Noto Serif SC',serif;font-weight:900;font-size:clamp(2rem,5vw,3rem);margin-bottom:.8rem;
  background:linear-gradient(135deg,#f6d78a,#ffffff 45%,#c0c0c0);-webkit-background-clip:text;background-clip:text;-webkit-text-fill-color:transparent;
}
.page-hero p{color:var(--text-2);max-width:600px;margin:0 auto;font-weight:300}

/* === Buttons === */
.btn-primary{
  padding:.85rem 2.1rem;background:linear-gradient(135deg,var(--indigo),#8b5cf6);color:#fff;border-radius:40px;
  font-weight:700;transition:all .3s;display:inline-block;box-shadow:0 4px 24px rgba(99,102,241,.35);
}
.btn-primary:hover{transform:translateY(-2px);box-shadow:0 8px 32px rgba(99,102,241,.5)}
.btn-ghost{
  padding:.85rem 2.1rem;border:1px solid var(--border);color:var(--text);border-radius:40px;font-weight:500;transition:all .3s;display:inline-block;
}
.btn-ghost:hover{border-color:var(--teal);color:var(--teal)}

/* === Hero (home) === */
#hero{
  position:relative;min-height:100vh;display:flex;align-items:center;text-align:center;
  padding:6rem 2rem 3rem;overflow:hidden;
}
.hero-bg{
  position:absolute;inset:0;z-index:-1;
  background:
    radial-gradient(ellipse at 30% 20%,rgba(99,102,241,.2),transparent 50%),
    radial-gradient(ellipse at 75% 80%,rgba(34,211,238,.15),transparent 50%),
    linear-gradient(180deg,var(--bg) 0%,var(--bg-2) 100%);
}
.hero-bg::after{
  content:'';position:absolute;inset:0;opacity:.05;
  background-image:linear-gradient(rgba(255,255,255,.4) 1px,transparent 1px),linear-gradient(90deg,rgba(255,255,255,.4) 1px,transparent 1px);
  background-size:44px 44px;
}
.hero-content{max-width:820px;margin:0 auto}
.hero-tag{
  display:inline-block;padding:.45rem 1.3rem;border:1px solid var(--border);border-radius:40px;
  font-size:.85rem;color:var(--teal);letter-spacing:.1em;margin-bottom:1.4rem;background:rgba(34,211,238,.06);
}
#hero h1{font-family:'Noto Serif SC',serif;font-weight:900;font-size:clamp(2.4rem,6vw,4rem);line-height:1.1;margin-bottom:1.2rem}
.accent{
  background:linear-gradient(135deg,var(--teal),var(--indigo-bright),var(--gold));-webkit-background-clip:text;background-clip:text;-webkit-text-fill-color:transparent;
}
.hero-sub{font-size:clamp(.95rem,2vw,1.1rem);color:var(--text-2);max-width:600px;margin:0 auto 2.4rem;font-weight:300}
.hero-cta{display:flex;gap:1rem;justify-content:center;flex-wrap:wrap}
.hero-stats{display:grid;grid-template-columns:repeat(4,1fr);gap:1rem;margin-top:3rem;padding-top:2rem;border-top:1px solid var(--border-2)}
.hero-stat strong{display:block;font-size:1.4rem;color:var(--teal);font-family:'Noto Serif SC',serif}
.hero-stat span{font-size:.82rem;color:var(--text-3)}

/* === Portal (home 入口) === */
.portal-grid{max-width:var(--maxw);margin:0 auto;padding:0 2rem 4rem;display:grid;grid-template-columns:repeat(3,1fr);gap:1.4rem}
.portal-card{
  background:var(--surface);border:1px solid var(--border-2);border-radius:var(--radius);padding:1.8rem;text-align:center;
  transition:all .35s;display:block;
}
.portal-card:hover{transform:translateY(-6px);border-color:var(--border);box-shadow:0 20px 50px rgba(0,0,0,.4)}
.portal-card .p-icon{font-size:2.4rem;display:block;margin-bottom:.8rem}
.portal-card h4{font-family:'Noto Serif SC',serif;font-size:1.15rem;color:var(--indigo-bright);margin-bottom:.4rem}
.portal-card p{font-size:.85rem;color:var(--text-2);font-weight:300;margin-bottom:.8rem}
.portal-card .go{font-size:.85rem;color:var(--teal)}

/* === About / products 通用卡片 === */
.dark-card{background:var(--surface);border:1px solid var(--border-2);border-radius:var(--radius);padding:1.8rem;transition:all .3s}
.dark-card:hover{border-color:var(--border);transform:translateY(-4px)}

/* === Products grid === */
.products-grid{max-width:var(--maxw);margin:0 auto;padding:0 2rem 4rem;display:grid;grid-template-columns:repeat(3,1fr);gap:1.5rem}
.product-card{background:var(--surface);border:1px solid var(--border-2);border-radius:var(--radius);overflow:hidden;transition:all .35s}
.product-card:hover{transform:translateY(-6px);border-color:var(--border);box-shadow:0 20px 50px rgba(0,0,0,.4)}
.product-img{height:200px;overflow:hidden;background:var(--bg-2)}
.product-img img{width:100%;height:100%;object-fit:contain;transition:transform .5s;background:#0a0c1a}
.product-card:hover .product-img img{transform:scale(1.05)}
.product-info{padding:1.4rem}
.product-info h3{font-family:'Noto Serif SC',serif;font-size:1.05rem;color:var(--indigo-bright);margin-bottom:.5rem}
.product-info p{font-size:.85rem;color:var(--text-2);font-weight:300;margin-bottom:.8rem}
.tag{display:inline-block;font-size:.72rem;color:var(--teal);background:rgba(34,211,238,.08);padding:.15rem .6rem;border-radius:30px}

/* === Videos === */
.video-grid{max-width:var(--maxw);margin:0 auto;padding:0 2rem 4rem;display:grid;grid-template-columns:repeat(3,1fr);gap:1.4rem}
.video-item{background:var(--surface);border:1px solid var(--border-2);border-radius:var(--radius);overflow:hidden;transition:all .35s}
.video-item:hover{border-color:var(--border);transform:translateY(-6px);box-shadow:0 20px 50px rgba(0,0,0,.4)}
.video-item video{width:100%;height:200px;object-fit:cover;display:block;background:#05060f}
.video-item p{padding:.9rem 1.1rem;font-size:.9rem;color:var(--text)}

/* === Tech === */
.tech-grid{max-width:var(--maxw);margin:0 auto;padding:0 2rem 4rem;display:grid;grid-template-columns:repeat(3,1fr);gap:1.5rem}
.tech-card{background:var(--surface);border:1px solid var(--border-2);border-radius:var(--radius);padding:1.8rem;transition:all .3s}
.tech-card:hover{border-color:var(--indigo);transform:translateY(-4px)}
.tech-card.highlight{background:linear-gradient(135deg,var(--indigo),#8b5cf6);border:none}
.tech-card.highlight p{color:rgba(255,255,255,.9)}
.tech-num{font-family:'Noto Serif SC',serif;font-size:2.2rem;font-weight:900;color:rgba(129,140,248,.2);display:block;margin-bottom:.5rem}
.tech-card.highlight .tech-num{color:rgba(255,255,255,.3)}
.tech-card h4{font-size:1.1rem;margin-bottom:.6rem}
.tech-card p{font-size:.88rem;color:var(--text-2);font-weight:300}

/* === Applications === */
.app-grid{max-width:var(--maxw);margin:0 auto;padding:0 2rem 4rem;display:grid;grid-template-columns:repeat(3,1fr);gap:1.2rem}
.app-item{background:var(--surface);border:1px solid var(--border-2);border-radius:var(--radius);padding:2rem;text-align:center;transition:all .3s}
.app-item:hover{border-color:var(--indigo);transform:translateY(-4px)}
.app-icon{font-size:2.2rem;display:block;margin-bottom:.8rem}
.app-item h4{font-size:1.05rem}

/* === Contact === */
.contact-wrap{max-width:var(--maxw);margin:0 auto 4rem;padding:4rem 2rem;display:grid;grid-template-columns:1fr 1fr;gap:3rem;background:var(--surface);border:1px solid var(--border);border-radius:var(--radius)}
.contact-info .section-tag{margin-bottom:.8rem}
.contact-info h2{font-family:'Noto Serif SC',serif;font-weight:900;font-size:clamp(1.6rem,3.5vw,2.2rem);line-height:1.2;margin-bottom:1rem}
.contact-info>p{color:var(--text-2);font-weight:300;margin-bottom:1.5rem}
.contact-items{display:flex;flex-direction:column;gap:1.2rem}
.contact-item{display:flex;align-items:flex-start;gap:1rem}
.contact-item svg{color:var(--teal);flex-shrink:0}
.contact-item span{display:block;font-size:.75rem;color:var(--text-3)}
.contact-item p{margin:0;font-size:.92rem;color:var(--text)}
.contact-form{display:flex;flex-direction:column;gap:.8rem;background:var(--bg-3);padding:2rem;border-radius:var(--radius)}
.contact-form h3{font-family:'Noto Serif SC',serif;font-size:1.2rem;margin-bottom:.5rem;color:var(--teal)}
.contact-form input,.contact-form textarea{background:var(--bg-2);border:1px solid var(--border-2);border-radius:var(--radius-sm);padding:.8rem 1rem;color:var(--text);font-size:.9rem;transition:border-color .2s}
.contact-form input:focus,.contact-form textarea:focus{outline:none;border-color:var(--indigo)}
.contact-form textarea{resize:vertical}
.form-submit{width:100%;margin-top:.4rem;border:none}

/* === Footer === */
footer{border-top:1px solid var(--border-2);padding:3rem 2rem 1.5rem;background:var(--bg-2)}
.footer-inner{max-width:var(--maxw);margin:0 auto;display:grid;grid-template-columns:1.5fr 2fr;gap:3rem;padding-bottom:2rem}
.footer-brand .logo{margin-bottom:1rem}
.footer-brand p{font-size:.85rem;color:var(--text-2);max-width:320px;font-weight:300}
.footer-copy{margin-top:.6rem!important;color:var(--text-3)!important}
.footer-links{display:grid;grid-template-columns:repeat(3,1fr);gap:1.5rem}
.footer-col h4{font-size:.9rem;color:var(--teal);margin-bottom:.8rem;font-weight:700}
.footer-col a{display:block;font-size:.85rem;color:var(--text-3);padding:.25rem 0;transition:color .2s}
.footer-col a:hover{color:var(--text)}

/* === Animations === */
@keyframes fadeUp{from{opacity:0;transform:translateY(30px)}to{opacity:1;transform:translateY(0)}}
.fade-in{opacity:0}
.fade-in.visible{animation:fadeUp .7s cubic-bezier(.2,.8,.2,1) forwards}

/* === Responsive === */
@media(max-width:900px){
  .nav-links{display:none}.menu-toggle{display:block}
  .hero-stats{grid-template-columns:repeat(2,1fr)}
  .products-grid,.video-grid,.tech-grid{grid-template-columns:repeat(2,1fr)}
  .portal-grid,.app-grid{grid-template-columns:repeat(2,1fr)}
  .contact-wrap{grid-template-columns:1fr;gap:2rem}
  .footer-inner{grid-template-columns:1fr;gap:2rem}
}
@media(max-width:560px){
  .nav-inner{padding:.7rem 1.2rem}
  #hero{padding:5rem 1.2rem 2rem}
  .hero-stats{grid-template-columns:1fr;gap:.8rem}
  .products-grid,.video-grid,.tech-grid{grid-template-columns:1fr;padding:0 1.2rem}
  .portal-grid,.app-grid{grid-template-columns:1fr;padding:0 1.2rem}
  .contact-wrap{padding:1.5rem 1.2rem}
  .footer-links{grid-template-columns:1fr;gap:1.5rem}
  .hero-cta{flex-direction:column;align-items:center}
  .btn-primary,.btn-ghost{width:100%;text-align:center}
}

/* === 小达 AI 玻璃智能助手（内嵌） === */
.ai-section{max-width:var(--maxw);margin:0 auto;padding:0 2rem 2.5rem}
.ai-embed{
  max-width:860px;margin:0 auto;background:var(--bg-2);border:1px solid var(--border);
  border-radius:20px;overflow:hidden;box-shadow:0 20px 60px rgba(0,0,0,.4);
  display:flex;flex-direction:column;
}
.ai-embed-header{
  background:linear-gradient(135deg,var(--indigo),#8b5cf6);color:#fff;
  padding:1rem 1.2rem;display:flex;align-items:center;gap:.8rem;
}
.ai-avatar{width:44px;height:44px;border-radius:50%;background:rgba(255,255,255,.2);display:flex;align-items:center;justify-content:center;font-size:1.4rem}
.ai-embed-header strong{display:block;font-size:1.05rem}
.ai-embed-header small{opacity:.85;font-size:.72rem}
.ai-online{margin-left:auto;font-size:.72rem;background:rgba(255,255,255,.2);padding:.2rem .7rem;border-radius:20px}
.ai-messages{height:280px;overflow-y:auto;padding:1rem;display:flex;flex-direction:column;gap:.6rem;background:var(--bg)}
.ai-msg{max-width:85%;padding:.6rem .9rem;border-radius:12px;font-size:.88rem;line-height:1.5;white-space:pre-line}
.ai-user{align-self:flex-end;background:var(--indigo);color:#fff;border-bottom-right-radius:4px}
.ai-bot{align-self:flex-start;background:var(--surface-2);color:var(--text);border-bottom-left-radius:4px}
.ai-input-wrap{display:flex;gap:.5rem;padding:.8rem;border-top:1px solid var(--border-2);background:var(--bg-2)}
#aiInputEmbed{flex:1;background:var(--bg);border:1px solid var(--border-2);border-radius:20px;padding:.65rem 1rem;color:var(--text);font-size:.9rem}
#aiInputEmbed:focus{outline:none;border-color:var(--indigo)}
.ai-send{background:linear-gradient(135deg,var(--indigo),#8b5cf6);color:#fff;border:none;border-radius:20px;padding:.65rem 1.2rem;cursor:pointer;font-weight:600}
.ai-send:hover{opacity:.9}
@media(max-width:600px){
  .ai-section{padding:0 1.2rem 2rem}
  .ai-messages{height:240px}
}

/* === 中英文切换按钮 === */
.lang-btn{
  min-width:40px;padding:.4rem .8rem;border-radius:20px;border:1px solid var(--border);
  background:transparent;color:var(--text-2);font-size:.8rem;font-weight:700;cursor:pointer;transition:all .25s;
}
.lang-btn:hover{border-color:var(--teal);color:var(--teal)}


/* === 语言切换按钮（导航栏内，汉堡菜单旁） === */
.fixed-lang-btn{
  min-width:44px;padding:.4rem .8rem;border-radius:20px;
  background:linear-gradient(135deg,var(--indigo),#8b5cf6);color:#fff;
  border:none;font-size:.82rem;font-weight:700;cursor:pointer;margin-left:.5rem;
  box-shadow:0 3px 12px rgba(99,102,241,.4);transition:all .3s;
}
.fixed-lang-btn:hover{transform:scale(1.05)}
@media(max-width:900px){
  .fixed-lang-btn{position:absolute;right:56px;top:50%;transform:translateY(-50%)}
}

/* === 语言按钮响应式控制 === */
/* 桌面端：显示 nav-links 里的 lang-btn，隐藏汉堡旁的 fixed-lang-btn */
@media(min-width:901px){
  .nav-links .lang-btn{display:inline-block}
  .fixed-lang-btn{display:none}
}
/* 移动端：nav-links折叠，显示汉堡旁的 fixed-lang-btn */
@media(max-width:900px){
  .nav-links .lang-btn{display:none}
  .fixed-lang-btn{display:inline-flex;align-items:center;justify-content:center}
  .menu-toggle{margin-left:.4rem}
}