/* DALIAN HUIYING TECHNOLOGY — "The Sounding Chart" design system */
:root{
  --abyss:#0a1117;
  --panel:#0e1a22;
  --panel2:#10212c;
  --line:#1c3240;
  --foam:#e9eff2;
  --mut:#8ba6b3;
  --gold:#e0a94e;    /* signal gold */
  --chart:#55b8cc;   /* chart cyan */
  --buoy:#d4573f;    /* buoy red */
  --kelp:#63a877;    /* kelp green */
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{background:var(--abyss);color:var(--foam);font-family:'Noto Sans SC',system-ui,sans-serif;font-size:16px;line-height:1.6}
.mono{font-family:'Overpass Mono',monospace}
.mut{color:var(--mut)}

/* bilingual — English default, .zh flips */
.zh{display:none}
html.zh .zh{display:inline}
html.zh .en{display:none}

/* signal-flag pennant strips */
.flags{height:14px;
  background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='96' height='14'%3E%3Cpolygon points='2,0 14,0 8,14' fill='%23e0a94e'/%3E%3Cpolygon points='26,0 38,0 32,14' fill='%2355b8cc'/%3E%3Cpolygon points='50,0 62,0 56,14' fill='%23d4573f'/%3E%3Cpolygon points='74,0 86,0 80,14' fill='%2363a877'/%3E%3C/svg%3E");
  background-repeat:repeat-x;background-position:center}

/* centered masthead — like a chart title block */
.mast{position:relative;padding:46px 20px 0;text-align:center;border-bottom:1px solid var(--line)}
.mast .seal{display:block;margin:0 auto 14px}
.mast .cname{font-family:'Marcellus','Noto Sans SC',serif;font-size:1.5rem;letter-spacing:.06em}
.mast .cname .zh{display:none}
html.zh .mast .cname .zh{display:inline}
html.zh .mast .cname .en{display:none}
.mast .csub{font-family:'Overpass Mono',monospace;font-size:.64rem;letter-spacing:.34em;color:var(--mut);margin-top:8px}
.mnav{display:flex;justify-content:center;gap:6px;flex-wrap:wrap;padding:20px 0 0}
.mnav a{color:var(--mut);text-decoration:none;font-family:'Overpass Mono',monospace;font-size:.72rem;letter-spacing:.14em;padding:8px 14px;border:1px solid transparent;border-bottom-color:var(--line)}
.mnav a:hover{color:var(--foam);border-color:var(--line)}
.mnav a.cta{color:var(--gold);border:1px solid var(--gold)}
.mnav .langbtn{margin-left:8px}
.langbtn{background:none;border:1px solid var(--line);color:var(--mut);font-family:'Overpass Mono',monospace;font-size:.72rem;letter-spacing:.12em;padding:8px 14px;cursor:pointer}
.langbtn:hover{color:var(--foam);border-color:var(--mut)}

/* right-edge vertical channel rail */
.rail{position:fixed;right:0;top:50%;transform:translateY(-50%);z-index:40;
  display:flex;flex-direction:column;background:var(--abyss);border:1px solid var(--line);border-right:0}
.rail a{writing-mode:vertical-rl;font-family:'Overpass Mono',monospace;font-size:.6rem;letter-spacing:.3em;
  color:var(--mut);text-decoration:none;padding:16px 8px;border-bottom:1px solid var(--line)}
.rail a:last-child{border-bottom:0}
.rail a:hover{color:var(--foam)}
.rail a.ca{border-left:3px solid var(--chart)}
.rail a.cb{border-left:3px solid var(--gold)}
.rail a.cc{border-left:3px solid var(--buoy)}
.rail a.cd{border-left:3px solid var(--kelp)}
@media(max-width:1150px){.rail{display:none}}

.wrap{max-width:1060px;margin:0 auto;padding:0 24px}
@media(max-width:1150px){.wrap{max-width:1000px}}

/* hero sounding chart */
.hero{display:grid;grid-template-columns:1fr 1fr;gap:40px;align-items:center;padding:64px 0 54px}
.hero .chart svg{width:100%;height:auto;display:block}
.kick{font-family:'Overpass Mono',monospace;font-size:.68rem;letter-spacing:.3em;color:var(--mut);margin-bottom:14px}
h1{font-family:'Marcellus','Noto Sans SC',serif;font-weight:400;font-size:clamp(2rem,4.4vw,3rem);line-height:1.14}
h2{font-family:'Marcellus','Noto Sans SC',serif;font-weight:400;font-size:1.9rem;line-height:1.2}
h3{font-family:'Marcellus','Noto Sans SC',serif;font-weight:400}
.lede{color:var(--mut);font-size:1.02rem;margin-top:18px}
.stats{display:flex;gap:0;margin-top:28px;border:1px solid var(--line)}
.stats div{flex:1;padding:14px 18px;border-right:1px solid var(--line)}
.stats div:last-child{border-right:0}
.stats b{display:block;font-family:'Marcellus',serif;font-weight:400;font-size:1.6rem;color:var(--chart)}
.stats div:nth-child(2) b{color:var(--gold)}
.stats div:nth-child(3) b{color:var(--buoy)}
.stats div:nth-child(4) b{color:var(--kelp)}
.stats span{font-family:'Overpass Mono',monospace;font-size:.62rem;letter-spacing:.18em;color:var(--mut)}
.bts{display:flex;gap:14px;margin-top:28px;flex-wrap:wrap}
.btn{display:inline-block;font-family:'Overpass Mono',monospace;font-size:.74rem;letter-spacing:.14em;text-decoration:none;padding:13px 24px;border:1px solid var(--line);color:var(--foam)}
.btn.solid{background:var(--chart);border-color:var(--chart);color:var(--abyss);font-weight:700}
.btn:hover{filter:brightness(1.15)}

/* sections */
.sec{padding:56px 0;border-top:1px solid var(--line)}
.sec-head{max-width:720px;margin-bottom:34px}
.sec-head h2{margin-bottom:12px}
.sec-head p{color:var(--mut)}

/* channel cards on index */
.chgrid{display:grid;grid-template-columns:repeat(4,1fr);gap:16px}
.ch{background:var(--panel);border:1px solid var(--line);border-top:4px solid;padding:20px}
.ch .cl{font-family:'Overpass Mono',monospace;font-size:.6rem;letter-spacing:.26em;color:var(--mut)}
.ch h3{font-size:1.2rem;margin:8px 0 6px}
.ch .cn{font-family:'Overpass Mono',monospace;font-size:.68rem;color:var(--mut)}
.ch p{color:var(--mut);font-size:.86rem;margin-top:10px}
.ch.ca{border-top-color:var(--chart)}.ch.ca h3{color:var(--chart)}
.ch.cb{border-top-color:var(--gold)}.ch.cb h3{color:var(--gold)}
.ch.cc{border-top-color:var(--buoy)}.ch.cc h3{color:var(--buoy)}
.ch.cd{border-top-color:var(--kelp)}.ch.cd h3{color:var(--kelp)}

/* sounding rows */
.chan{scroll-margin-top:30px}
.chan-head{display:flex;align-items:baseline;gap:16px;padding:14px 0 10px;border-bottom:2px solid var(--line)}
.chan-head .cl{font-family:'Overpass Mono',monospace;font-size:.66rem;letter-spacing:.3em}
.chan-head h3{font-size:1.45rem}
.chan-head .cnt{margin-left:auto;font-family:'Overpass Mono',monospace;font-size:.68rem;color:var(--mut)}
.chan.a .chan-head{border-color:var(--chart)}.chan.a .cl,.chan.a h3{color:var(--chart)}
.chan.b .chan-head{border-color:var(--gold)}.chan.b .cl,.chan.b h3{color:var(--gold)}
.chan.c .chan-head{border-color:var(--buoy)}.chan.c .cl,.chan.c h3{color:var(--buoy)}
.chan.d .chan-head{border-color:var(--kelp)}.chan.d .cl,.chan.d h3{color:var(--kelp)}
.snd{display:flex;align-items:center;gap:18px;padding:13px 4px;border-bottom:1px dashed var(--line)}
.snd:hover{background:var(--panel)}
.snum{font-family:'Overpass Mono',monospace;font-size:.78rem;min-width:64px;display:flex;align-items:center;gap:8px}
.snum i{display:inline-block;width:9px;height:9px;transform:rotate(45deg);flex:none}
.chan.a .snum{color:var(--chart)}.chan.a .snum i{background:var(--chart)}
.chan.b .snum{color:var(--gold)}.chan.b .snum i{background:var(--gold)}
.chan.c .snum{color:var(--buoy)}.chan.c .snum i{background:var(--buoy)}
.chan.d .snum{color:var(--kelp)}.chan.d .snum i{background:var(--kelp)}
.sname{flex:1}
.sname .en{display:block;font-size:.94rem}
.sname .zh{display:none;font-size:.9rem}
html.zh .sname .en{display:none}
html.zh .sname .zh{display:block}
.sname small{color:var(--mut);font-size:.74rem;display:block}
.stag{font-family:'Overpass Mono',monospace;font-size:.6rem;letter-spacing:.14em;padding:4px 10px;border:1px solid var(--line);color:var(--mut);white-space:nowrap}

/* split / cards / faq */
.split{display:grid;grid-template-columns:1fr 1fr;gap:44px;align-items:center}
.ccard{background:var(--panel);border:1px solid var(--line);border-left:4px solid var(--chart);padding:18px 20px;margin-bottom:14px}
.clab{font-family:'Overpass Mono',monospace;font-size:.62rem;letter-spacing:.22em;color:var(--mut);margin-bottom:6px}
.cval{font-size:1rem}
.faq details{background:var(--panel);border:1px solid var(--line);margin-bottom:12px}
.faq summary{cursor:pointer;padding:16px 20px;font-family:'Marcellus','Noto Sans SC',serif;font-size:1.05rem;list-style:none}
.faq summary::-webkit-details-marker{display:none}
.faq summary::before{content:"+";font-family:'Overpass Mono',monospace;color:var(--chart);margin-right:12px}
.faq details[open] summary::before{content:"−"}
.faq .fa{padding:0 20px 18px 52px;color:var(--mut);font-size:.92rem}
.faq .fa .zh{display:none}
html.zh .faq .fa .zh{display:inline}
html.zh .faq .fa .en{display:none}

/* contact */
.cgrid{display:grid;grid-template-columns:5fr 7fr;gap:40px;align-items:start}
.req{background:var(--panel);border:1px solid var(--line);padding:26px}
.fhead{display:flex;justify-content:space-between;align-items:baseline;border-bottom:1px solid var(--line);padding-bottom:14px;margin-bottom:20px}
.frow{display:grid;grid-template-columns:1fr 1fr;gap:16px;margin-bottom:16px}
.frow.one{grid-template-columns:1fr}
label{display:block;font-family:'Overpass Mono',monospace;font-size:.62rem;letter-spacing:.2em;color:var(--mut);margin-bottom:7px}
input,select,textarea{width:100%;background:var(--abyss);border:1px solid var(--line);color:var(--foam);font-family:'Noto Sans SC',sans-serif;font-size:.92rem;padding:11px 13px;outline:none}
input:focus,select:focus,textarea:focus{border-color:var(--chart)}
textarea{min-height:130px;resize:vertical}
.fnote{font-size:.78rem;color:var(--mut);margin-top:14px}
.rules3{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}
.rule3{background:var(--panel);border:1px solid var(--line);border-top:3px solid var(--line);padding:18px}
.rule3 h3{font-size:1.05rem;margin-bottom:8px}
.rule3 p{color:var(--mut);font-size:.86rem}

/* legal */
.legal h2{font-size:2rem;margin-bottom:6px}
.legal .eff{font-family:'Overpass Mono',monospace;font-size:.68rem;letter-spacing:.22em;color:var(--mut);margin-bottom:26px}
.legal h3{font-size:1.2rem;margin:30px 0 10px;color:var(--chart)}
.legal p,.legal li{color:var(--mut);font-size:.93rem;margin-bottom:10px}
.legal strong{color:var(--foam)}
.legal ul{padding-left:22px}
.legal .box{background:var(--panel);border:1px solid var(--line);padding:18px 22px;margin:16px 0}

footer{border-top:1px solid var(--line);padding:44px 0 30px;margin-top:20px}
.fgrid{display:grid;grid-template-columns:2fr 1fr 1fr;gap:34px}
footer h4{font-family:'Overpass Mono',monospace;font-size:.66rem;letter-spacing:.26em;color:var(--mut);margin-bottom:14px}
footer a{display:block;color:var(--mut);text-decoration:none;font-size:.88rem;padding:3px 0}
footer a:hover{color:var(--foam)}
.fbot{display:flex;justify-content:space-between;gap:14px;flex-wrap:wrap;margin-top:34px;padding-top:18px;border-top:1px solid var(--line);font-size:.78rem;color:var(--mut)}

@media(max-width:900px){
  .hero{grid-template-columns:1fr;padding-top:36px}
  .chgrid{grid-template-columns:1fr 1fr}
  .split,.cgrid{grid-template-columns:1fr}
  .frow{grid-template-columns:1fr}
  .fgrid{grid-template-columns:1fr}
  .rules3{grid-template-columns:1fr}
  .sname small{display:none}
  .stag{display:none}
}