*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{font-size:16px;-webkit-text-size-adjust:100%}
body{font-family:"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;background:#041820;color:#a8c8d8;line-height:1.65}
img{max-width:100%;height:auto;display:block}
a{color:#00bcd4;text-decoration:none}
a:hover{text-decoration:underline}
ul{list-style:none}
.container{width:min(1140px,92vw);margin:0 auto}

.site-header{position:sticky;top:0;z-index:100;background:#062028;border-bottom:1px solid #0a3848}
.header-inner{display:flex;align-items:center;justify-content:space-between;padding:.65rem 0;gap:1rem}
.logo{font-weight:800;font-size:.95rem;color:#00bcd4;letter-spacing:.04em;display:flex;align-items:center;gap:.55rem}
.logo-mask{width:26px;height:18px;border:2px solid #00bcd4;border-radius:50% 50% 45% 45%;position:relative}
.logo-mask::after{content:"";position:absolute;bottom:-4px;left:50%;transform:translateX(-50%);width:12px;height:4px;background:#00bcd4;border-radius:0 0 4px 4px}
.nav-main{display:flex;flex-wrap:wrap;gap:.3rem 1.1rem;font-size:.82rem}
.nav-main a{color:#5a8898;font-weight:600}
.nav-main a.active,.nav-main a:hover{color:#00bcd4;text-decoration:none}
.btn-nav{display:inline-block;background:#0a3848;color:#00bcd4!important;border:1px solid #00bcd4;padding:.4rem 1rem;font-weight:800;font-size:.8rem;text-decoration:none!important}
.btn-nav:hover{background:#0e4858}

.section{padding:3.1rem 0}
.section-title{font-size:clamp(1.15rem,3vw,1.5rem);font-weight:800;margin-bottom:.35rem;color:#e0f4f8;letter-spacing:.02em}
.section-lead{color:#5a8898;font-size:.88rem;margin-bottom:1.65rem;max-width:640px}

.footer{background:#030f14;border-top:1px solid #0a3848;padding:2.3rem 0 0;font-size:.84rem}
.footer-grid{display:grid;grid-template-columns:1.4fr 1fr 1fr;gap:1.8rem;margin-bottom:1.6rem}
.footer h3{font-size:.88rem;color:#00bcd4;margin-bottom:.6rem;font-weight:800}
.footer a{color:#5a8898}
.footer-links{display:flex;flex-wrap:wrap;gap:.35rem .9rem}
.footer-bottom{border-top:1px solid #0a2838;padding-top:.9rem;text-align:center;color:#3a5868;font-size:.75rem}

.faq-list{display:flex;flex-direction:column;gap:.45rem}
.faq-item{background:#062028;border:1px solid #0a3848}
.faq-q{width:100%;text-align:left;padding:.95rem 1.1rem;font-weight:800;font-size:.88rem;background:transparent;border:none;cursor:pointer;color:#e0f4f8;display:flex;justify-content:space-between;align-items:center;font-family:inherit}
.faq-q::after{content:"+";font-size:1.1rem;color:#00bcd4;font-weight:400}
.faq-item.open .faq-q::after{content:"−"}
.faq-a{display:none;padding:0 1.1rem .95rem;font-size:.84rem;color:#5a8898;line-height:1.65}
.faq-item.open .faq-a{display:block}

.btn-dive{display:inline-block;background:#00bcd4;color:#041820;border:1px solid #00bcd4;padding:.58rem 1.2rem;font-weight:800;font-size:.86rem;text-decoration:none!important}
.btn-dive:hover{background:#26c6da}
.btn-surface{display:inline-block;color:#80deea;border:1px solid #0a3848;padding:.58rem 1.2rem;font-weight:700;font-size:.86rem;text-decoration:none!important}
.btn-surface:hover{border-color:#80deea}

@media(max-width:768px){
  .header-inner{flex-wrap:wrap}
  .footer-grid{grid-template-columns:1fr}
}