/* Bi Home & Legacy — brand palette */
:root{
  --green:#0F3D2E; --teal:#0E4A47; --ocean:#14324A; --mist:#7FA3B8;
  --gold:#CDB98A; --ivory:#F5F6F1; --sage:#EEF2EB;
  --ink:#1A2B26; --muted:#4F625C; --line:rgba(15,61,46,.14);
  --serif-en:"Playfair Display",Georgia,"Times New Roman",serif;
  --serif-zh:"Noto Serif SC","Songti SC","STSong",serif;
  --sans:"Montserrat","Noto Sans SC","PingFang SC","Microsoft YaHei",system-ui,sans-serif;
  --wrap:1180px; --radius:4px;
}
*,*::before,*::after{box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{margin:0;font-family:var(--sans);font-size:16px;line-height:1.75;color:var(--ink);background:var(--ivory);-webkit-font-smoothing:antialiased}
img{max-width:100%;display:block}
a{color:inherit}
h1,h2,h3{font-family:var(--serif-en),var(--serif-zh);font-weight:600;line-height:1.25;margin:0 0 .5em;color:var(--green);letter-spacing:.005em}
html[data-lang="zh"] h1,html[data-lang="zh"] h2,html[data-lang="zh"] h3{font-family:var(--serif-zh);font-weight:700;letter-spacing:.04em}
h1,h2{text-wrap:balance}
h1 em,h2 em{font-style:italic;color:var(--teal)}
p{margin:0 0 1em}

/* language toggle */
html[data-lang="zh"] body [lang="en"]{display:none!important}
html[data-lang="en"] body [lang="zh"]{display:none!important}

.wrap{max-width:var(--wrap);margin:0 auto;padding:0 32px}
.skip{position:absolute;left:-999px;top:0;background:var(--green);color:#fff;padding:8px 14px;z-index:100}
.skip:focus{left:8px}
.ph{color:#8a6d2b;background:rgba(205,185,138,.18);border:1px dashed rgba(160,130,60,.55);padding:1px 6px;border-radius:3px;font-size:.92em}
.section-dark .ph,.site-footer .ph,.hero .ph{color:#e6d7ad;background:rgba(205,185,138,.12);border-color:rgba(205,185,138,.5)}
p.ph{display:inline-block}

/* header */
.site-header{position:sticky;top:0;z-index:50;background:rgba(15,61,46,.97);backdrop-filter:saturate(140%) blur(8px);border-bottom:1px solid rgba(205,185,138,.25)}
.header-inner{display:flex;align-items:center;gap:28px;height:76px}
.brand{display:flex;align-items:center;gap:12px;text-decoration:none;color:var(--ivory);flex-shrink:0}
.brand-icon{width:44px;height:44px}
.brand-text{display:flex;flex-direction:column;line-height:1.15}
.brand-en{font-family:var(--serif-en);font-weight:600;font-size:19px;letter-spacing:.08em;text-transform:uppercase}
.brand-en em{color:var(--gold);font-style:italic;text-transform:none}
.brand-zh{font-family:var(--serif-zh);font-size:12.5px;letter-spacing:.18em;color:rgba(245,246,241,.78);margin-top:3px}
.nav{display:flex;align-items:center;gap:26px;margin-left:auto}
.nav a{text-decoration:none;color:rgba(245,246,241,.86);font-size:14px;font-weight:500;letter-spacing:.04em;white-space:nowrap;transition:color .2s}
.nav a:hover{color:var(--gold)}
.nav .nav-cta{border:1px solid var(--gold);color:var(--ivory);padding:8px 16px;border-radius:var(--radius)}
.nav .nav-cta:hover{background:var(--gold);color:var(--green)}
.header-tools{display:flex;align-items:center;gap:12px}
.lang-toggle{white-space:nowrap;flex-shrink:0;display:flex;align-items:center;gap:4px;color:rgba(245,246,241,.4);font-size:13px}
.lang-toggle button{background:none;border:0;color:rgba(245,246,241,.6);font:600 13px var(--sans);letter-spacing:.06em;cursor:pointer;padding:6px 4px}
.lang-toggle button[aria-pressed="true"]{color:var(--gold)}
.menu-btn{display:none;background:none;border:0;width:40px;height:40px;padding:9px;cursor:pointer}
.menu-btn span{display:block;height:1.5px;background:var(--ivory);margin:5px 0;transition:.25s}

/* buttons */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:10px;padding:15px 30px;border-radius:var(--radius);font:600 14px/1 var(--sans);letter-spacing:.1em;text-decoration:none;cursor:pointer;border:1px solid transparent;transition:all .2s}
html[data-lang="en"] .btn{text-transform:uppercase;font-size:13px}
.btn-primary{background:var(--ivory);color:var(--green);border-color:var(--gold)}
.btn-primary:hover{background:var(--gold);color:var(--green)}
.btn-ghost{color:var(--ivory);border-color:rgba(245,246,241,.45)}
.btn-ghost:hover{border-color:var(--gold);color:var(--gold)}
.btn-outline{color:var(--green);border-color:var(--green)}
.btn-outline:hover{background:var(--green);color:var(--ivory)}
.btn-block{width:100%}
.yt{width:20px;height:20px;fill:currentColor}

/* hero */
.hero{position:relative;color:var(--ivory);min-height:min(88vh,820px);display:flex;align-items:center;overflow:hidden;background:var(--green)}
.hero-bg{position:absolute;inset:0;background:
  linear-gradient(90deg,rgba(10,40,34,.94) 0%,rgba(14,74,71,.78) 38%,rgba(15,61,46,.2) 72%,rgba(15,61,46,.05) 100%),
  linear-gradient(0deg,rgba(20,50,74,.65) 0%,rgba(20,50,74,0) 40%),
  url("../img/hero.jpg") center right/cover no-repeat}
.hero-inner{position:relative;padding-top:110px;padding-bottom:110px;width:100%}
.hero h1{color:var(--ivory);font-size:clamp(36px,5.2vw,66px);max-width:780px;margin-bottom:24px}
html[data-lang="zh"] .hero h1{letter-spacing:.06em;line-height:1.3}
.hero h1 em{color:var(--gold)}
.hero-sub{font-size:clamp(16px,1.5vw,19px);max-width:560px;color:rgba(245,246,241,.88);margin-bottom:38px}
.hero-actions{display:flex;gap:16px;flex-wrap:wrap}
.hero-pillars{list-style:none;padding:0;margin:64px 0 0;display:flex;gap:0;max-width:560px;border-top:1px solid rgba(205,185,138,.45)}
.hero-pillars li{flex:1;padding:16px 0 0;font-family:var(--serif-zh);font-size:15px;letter-spacing:.3em;color:rgba(245,246,241,.85)}
html[data-lang="en"] .hero-pillars li{font-family:var(--serif-en);letter-spacing:.12em;font-style:italic}
.hero-pillars li+li{padding-left:18px;border-left:1px solid rgba(205,185,138,.3)}

/* sections */
.section{padding:120px 0}
.section-tint{background:var(--sage)}
.section-dark{background:linear-gradient(170deg,var(--teal) 0%,var(--green) 55%,var(--ocean) 100%);color:rgba(245,246,241,.88)}
.section-dark h2,.section-dark h3{color:var(--ivory)}
.section-dark h2 em{color:var(--gold)}
.section-head{text-align:center;max-width:720px;margin:0 auto 64px}
.section-head.left{text-align:left;margin:0}
.eyebrow{font:600 12px var(--sans);letter-spacing:.28em;text-transform:uppercase;color:var(--teal);margin-bottom:18px;display:inline-flex;align-items:center;gap:14px}
.eyebrow::before{content:"";width:32px;height:1px;background:var(--gold)}
.eyebrow.light{color:var(--gold)}
h2{font-size:clamp(28px,3.4vw,44px)}
.lead{font-size:17px;color:var(--muted)}
.section-dark .lead{color:rgba(245,246,241,.78)}
.center{text-align:center;margin-top:48px}

/* service cards */
.cards{display:grid;grid-template-columns:repeat(4,1fr);gap:24px}
.card{background:#fff;border:1px solid var(--line);border-top:2px solid var(--gold);padding:36px 28px 32px;border-radius:var(--radius);transition:transform .25s,box-shadow .25s}
.card:hover{transform:translateY(-4px);box-shadow:0 18px 40px -22px rgba(15,61,46,.35)}
.card-icon{width:52px;height:52px;margin-bottom:22px}
.card-icon svg{width:100%;height:100%;fill:none;stroke:var(--green);stroke-width:1.6;stroke-linecap:round;stroke-linejoin:round}
.card-kicker{font:600 11px var(--sans);letter-spacing:.24em;text-transform:uppercase;color:var(--mist);margin-bottom:8px}
.card h3{font-size:22px}
.card p{font-size:15px;color:var(--muted)}
.card .note{font-size:13px;color:var(--teal);border-top:1px solid var(--line);padding-top:12px;margin:0}
.card .ph{font-size:12.5px}

/* about */
.about{display:grid;grid-template-columns:5fr 7fr;gap:80px;align-items:center}
.portrait-frame{position:relative;aspect-ratio:4/5;border-radius:var(--radius);overflow:hidden;background:var(--ivory)}
.portrait-frame::after{content:"";position:absolute;inset:14px;border:1px solid var(--gold);pointer-events:none;border-radius:2px}
.portrait-frame>img{width:100%;height:100%;object-fit:cover}
.portrait-ph{height:100%;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:18px;background:linear-gradient(160deg,#fff,var(--ivory));color:#8a6d2b;font-size:14px}
.portrait-ph img{width:120px;opacity:.85}
.creds{list-style:none;padding:0;margin:28px 0 0;border-top:1px solid var(--line)}
.creds li{display:flex;justify-content:space-between;gap:20px;padding:14px 0;border-bottom:1px solid var(--line);font-size:14.5px}
.creds .k{color:var(--muted);font-weight:500}
.creds .v{text-align:right}

/* why */
.why-grid{display:grid;grid-template-columns:1fr;gap:56px}
.why-flow{display:flex;align-items:center;justify-content:center;gap:0}
.flow-step{display:flex;flex-direction:column;align-items:center;justify-content:center;width:120px;height:120px;border:1px solid rgba(205,185,138,.7);border-radius:50%;font-family:var(--serif-zh);font-size:20px;letter-spacing:.2em;color:var(--ivory);flex-shrink:0}
html[data-lang="en"] .flow-step{font-family:var(--serif-en);letter-spacing:.04em;font-style:italic}
.flow-step .n{font:600 11px var(--sans);letter-spacing:.2em;color:var(--gold);margin-bottom:4px;font-style:normal}
.flow-line{flex:1;max-width:110px;height:1px;background:linear-gradient(90deg,rgba(205,185,138,.7),rgba(127,163,184,.7))}
.why-items{display:grid;grid-template-columns:repeat(2,1fr);gap:0;border-top:1px solid rgba(205,185,138,.3)}
.why-item{padding:36px 40px 28px 0;border-bottom:1px solid rgba(205,185,138,.3)}
.why-item:nth-child(even){padding-left:40px;padding-right:0;border-left:1px solid rgba(205,185,138,.3)}
.why-item h3{font-size:22px}
.why-item p{font-size:15.5px;margin:0}

/* process */
.process{display:grid;grid-template-columns:1fr 1fr;gap:80px;align-items:center}
.process-img{margin:0;position:relative}
.process-img img{border-radius:var(--radius);width:100%;aspect-ratio:4/3;object-fit:cover}
.process-img::before{content:"";position:absolute;inset:-16px 16px 16px -16px;border:1px solid var(--gold);border-radius:var(--radius);z-index:-1}
.process{position:relative;z-index:0}
.steps{list-style:none;counter-reset:s;padding:0;margin:28px 0 0}
.steps li{counter-increment:s;position:relative;padding:0 0 22px 64px}
.steps li::before{content:"0" counter(s);position:absolute;left:0;top:2px;font:italic 600 26px var(--serif-en);color:var(--gold)}
.steps h3{font-size:19px;margin-bottom:4px}
.steps p{font-size:15px;color:var(--muted);margin:0}

/* videos */
.videos{display:grid;grid-template-columns:repeat(3,1fr);gap:28px}
.video h3{font-size:17px;margin-top:16px;line-height:1.5}
.video-frame{position:relative;aspect-ratio:16/9;border-radius:var(--radius);overflow:hidden;background:linear-gradient(150deg,var(--teal),var(--green) 60%,var(--ocean));cursor:pointer}
.video-frame img{width:100%;height:100%;object-fit:cover}
.video-frame iframe{position:absolute;inset:0;width:100%;height:100%;border:0}
.video-frame .play{position:absolute;inset:0;margin:auto;width:68px;height:68px;border-radius:50%;background:rgba(245,246,241,.92);display:flex;align-items:center;justify-content:center;border:0;cursor:pointer;transition:transform .2s;box-shadow:0 8px 24px rgba(0,0,0,.25)}
.video-frame .play::after{content:"";border-left:18px solid var(--green);border-top:11px solid transparent;border-bottom:11px solid transparent;margin-left:5px}
.video-frame:hover .play{transform:scale(1.07)}
.video-empty{position:absolute;inset:0;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:10px;color:rgba(245,246,241,.85);font-size:13px;text-align:center;padding:16px;cursor:default}
.video-empty img{width:64px;opacity:.9}
.video-empty code{font-size:11.5px;color:var(--gold)}

/* faq */
.faq-wrap{display:grid;grid-template-columns:4fr 8fr;gap:80px;align-items:start}
.faq details{border-bottom:1px solid var(--line)}
.faq details:first-child{border-top:1px solid var(--line)}
.faq summary{list-style:none;cursor:pointer;padding:24px 48px 24px 0;position:relative;font-family:var(--serif-zh);font-weight:700;font-size:18px;color:var(--green);letter-spacing:.03em}
html[data-lang="en"] .faq summary{font-family:var(--serif-en);font-weight:600;letter-spacing:0}
.faq summary::-webkit-details-marker{display:none}
.faq summary::after{content:"";position:absolute;right:6px;top:50%;width:12px;height:12px;border-right:1.5px solid var(--gold);border-bottom:1.5px solid var(--gold);transform:translateY(-70%) rotate(45deg);transition:transform .25s}
.faq details[open] summary::after{transform:translateY(-30%) rotate(-135deg)}
.faq details p{color:var(--muted);font-size:15.5px;padding:0 48px 24px 0;margin:0}

/* contact */
.contact{display:grid;grid-template-columns:5fr 7fr;gap:72px;align-items:start}
.contact-list{list-style:none;padding:0;margin:32px 0;border-top:1px solid rgba(205,185,138,.3)}
.contact-list li{display:flex;justify-content:space-between;gap:16px;padding:14px 0;border-bottom:1px solid rgba(205,185,138,.3);font-size:14.5px}
.contact-list .k{color:var(--gold);font-weight:500;letter-spacing:.06em;flex-shrink:0}
.contact-list .v{text-align:right}
.qr-ph{width:140px;height:140px;border:1px dashed rgba(205,185,138,.6);display:flex;align-items:center;justify-content:center;text-align:center;font-size:12.5px;color:#e6d7ad;border-radius:var(--radius);padding:10px}
.form{background:var(--ivory);color:var(--ink);padding:44px;border-radius:var(--radius);border-top:2px solid var(--gold);box-shadow:0 30px 60px -30px rgba(0,0,0,.45)}
.field-row{display:grid;grid-template-columns:1fr 1fr;gap:20px}
.field{display:block;margin:0 0 20px;border:0;padding:0;min-width:0}
.field>span,.field legend{display:block;font-size:13px;font-weight:600;letter-spacing:.06em;color:var(--green);margin-bottom:8px;padding:0}
.field i{color:#9b7b3a;font-style:normal}
.field input,.field textarea{width:100%;font:15px var(--sans);color:var(--ink);background:#fff;border:1px solid rgba(15,61,46,.2);border-radius:var(--radius);padding:12px 14px;transition:border-color .2s,box-shadow .2s}
.field input:focus,.field textarea:focus{outline:0;border-color:var(--teal);box-shadow:0 0 0 3px rgba(14,74,71,.12)}
.field input.invalid{border-color:#b04a3a}
.checks{display:flex;flex-wrap:wrap;gap:10px}
.checks label{cursor:pointer;position:relative}
.field .checks input{position:absolute;left:0;top:0;width:1px;height:1px;opacity:0;pointer-events:none}
.checks label>span{display:inline-block;padding:9px 16px;border:1px solid rgba(15,61,46,.25);border-radius:999px;font-size:14px;color:var(--green);background:#fff;transition:all .2s}
.checks input:checked+span{background:var(--green);color:var(--ivory);border-color:var(--green)}
.checks input:focus-visible+span{box-shadow:0 0 0 3px rgba(14,74,71,.25)}
.consent{display:flex;gap:10px;align-items:flex-start;font-size:13px;color:var(--muted);margin:4px 0 24px;line-height:1.6}
.consent input{margin-top:3px;accent-color:var(--green);flex-shrink:0}
.form .btn-primary{background:var(--green);color:var(--ivory);border-color:var(--green)}
.form .btn-primary:hover{background:var(--teal)}
.form-status{margin:14px 0 0;font-size:14px;min-height:1.5em}
.form-status.ok{color:var(--teal)}
.form-status.err{color:#b04a3a}

/* footer */
.site-footer{background:#0B2E23;color:rgba(245,246,241,.7);padding:72px 0 36px;font-size:13.5px}
.footer-top{display:flex;justify-content:space-between;align-items:center;gap:32px;padding-bottom:36px;border-bottom:1px solid rgba(205,185,138,.25)}
.footer-logo{width:380px;height:auto}
.footer-nav{display:flex;gap:26px;flex-wrap:wrap}
.footer-nav a{text-decoration:none;color:rgba(245,246,241,.8)}
.footer-nav a:hover{color:var(--gold)}
.licenses{padding:28px 0 8px}
.licenses p{margin:0 0 6px}
.licenses strong{color:var(--ivory)}
.disclaimer{padding:16px 0 24px;font-size:12.5px;line-height:1.75;color:rgba(245,246,241,.58);max-width:980px}
.disclaimer strong{color:rgba(245,246,241,.85)}
.disclaimer p{margin:0 0 10px}
.footer-bottom{display:flex;justify-content:space-between;align-items:center;gap:20px;padding-top:24px;border-top:1px solid rgba(205,185,138,.18)}
.eho{display:flex;align-items:center;gap:10px;color:rgba(245,246,241,.8);font:600 10.5px/1.25 var(--sans);letter-spacing:.1em}
.eho svg{width:34px;height:34px}
.copy{margin:0;font-size:12.5px}

/* ---------- responsive ---------- */
@media (max-width:1180px){
  .nav{gap:18px}
  .nav a{font-size:13px}
  .cards{grid-template-columns:repeat(2,1fr)}
}
@media (max-width:1024px){
  .menu-btn{display:block}
  .header-inner{gap:12px}
  .header-tools{margin-left:auto}
  .nav{position:fixed;top:76px;left:0;right:0;flex-direction:column;align-items:stretch;gap:0;background:var(--green);padding:8px 32px 28px;border-bottom:1px solid rgba(205,185,138,.3);transform:translateY(-12px);opacity:0;visibility:hidden;transition:all .25s;margin:0}
  .nav.open{transform:none;opacity:1;visibility:visible}
  .nav a{padding:15px 0;border-bottom:1px solid rgba(245,246,241,.1);font-size:15px}
  .nav .nav-cta{margin-top:18px;text-align:center;border-bottom:1px solid var(--gold)}
  .menu-btn[aria-expanded="true"] span:nth-child(1){transform:translateY(6.5px) rotate(45deg)}
  .menu-btn[aria-expanded="true"] span:nth-child(2){opacity:0}
  .menu-btn[aria-expanded="true"] span:nth-child(3){transform:translateY(-6.5px) rotate(-45deg)}
  .about,.process,.contact,.faq-wrap{grid-template-columns:1fr;gap:56px}
  .about .portrait{max-width:420px}
  .section-head.left{text-align:center;margin:0 auto 8px;max-width:720px}
}
@media (max-width:720px){
  .wrap{padding:0 22px}
  .section{padding:80px 0}
  .header-inner{height:66px}
  .nav{top:66px;padding:8px 22px 24px}
  .brand-icon{width:38px;height:38px}
  .brand-en{font-size:15px;letter-spacing:.06em}
  .brand-zh{font-size:11px;letter-spacing:.12em}
  .hero{min-height:auto}
  .hero-bg{background:
    linear-gradient(180deg,rgba(10,40,34,.55) 0%,rgba(14,74,71,.82) 45%,rgba(15,61,46,.96) 100%),
    url("../img/hero.jpg") 70% center/cover no-repeat}
  .hero-inner{padding-top:120px;padding-bottom:72px}
  .hero-actions .btn{flex:1 1 100%}
  .hero-pillars{margin-top:48px}
  .hero-pillars li{font-size:14px;letter-spacing:.18em}
  .hero-pillars li+li{padding-left:12px}
  .section-head{margin-bottom:44px}
  .cards,.videos{grid-template-columns:1fr}
  .why-flow{flex-wrap:wrap;gap:14px 0}
  .flow-step{width:74px;height:74px;font-size:15px;letter-spacing:.1em}
  .flow-line{max-width:none;min-width:8px}
  .why-items{grid-template-columns:1fr}
  .why-item,.why-item:nth-child(even){padding:28px 0 22px;border-left:0}
  .process-img::before{inset:-10px 10px 10px -10px}
  .form{padding:28px 22px}
  .field-row{grid-template-columns:1fr;gap:0}
  .footer-top,.footer-bottom{flex-direction:column;align-items:flex-start}
  .footer-logo{width:300px}
  .creds li,.contact-list li{flex-direction:column;gap:2px}
  .creds .v,.contact-list .v{text-align:left}
  .faq summary{font-size:16.5px}
}
@media (prefers-reduced-motion:reduce){*{transition:none!important;scroll-behavior:auto!important}}

/* fixes after preview review */
img{height:auto}
.brand-icon{height:44px}
html[data-lang="zh"] h1,html[data-lang="zh"] h2{word-break:keep-all;overflow-wrap:anywhere}
@media (max-width:720px){.brand-icon{height:38px}}
@media (max-width:720px){html[data-lang="en"] .hero-pillars li{font-size:12.5px;letter-spacing:.02em}}

/* v1.1 — brand panel (replaces portrait until a photo is added) */
.brand-panel{color:var(--green);gap:10px;text-align:center;padding:24px}
.brand-panel img{margin-bottom:10px}
.brand-panel .bp-name{font-family:var(--serif-en),serif;font-size:30px;font-weight:600;letter-spacing:.02em}
.brand-panel .bp-zh{font-family:var(--serif-zh),serif;font-size:18px;color:var(--teal)}
.brand-panel .bp-tag{margin-top:8px;font-size:12.5px;letter-spacing:.18em;color:#8a6d2b;text-transform:uppercase}
/* YouTube topics */
.topics{list-style:none;padding:0;margin:8px auto 0;display:flex;flex-wrap:wrap;justify-content:center;gap:12px;max-width:820px}
.topics li{padding:10px 22px;border:1px solid var(--gold);border-radius:999px;background:#fff;color:var(--green);font-weight:500;font-size:15px}
.section-tint .center{margin-top:36px}
/* contact links */
.contact-list a,.licenses a{color:inherit;text-decoration:none;border-bottom:1px solid rgba(205,185,138,.5)}
.contact-list a:hover,.licenses a:hover{color:var(--gold)}
.form-note{font-size:13px;line-height:1.6;opacity:.8;margin:12px 0 0}
.form-note a{color:inherit}