:root{
  --bg:#f6f8fb; --bg-alt:#eef2f7; --card:#ffffff; --ink:#15233b;
  --muted:#5c6b82; --line:#dfe6ef; --brand:#185fa5; --brand2:#0e3f73;
  --accent:#2f9e6b; --lg-cap:#2483e0; --lg-low:#15233b; --shadow:0 8px 24px rgba(20,40,80,.08);
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","Microsoft YaHei",Roboto,Helvetica,Arial,sans-serif;
  color:var(--ink);background:var(--bg);line-height:1.6;-webkit-font-smoothing:antialiased}
a{color:inherit;text-decoration:none}
.wrap{max-width:1080px;margin:0 auto;padding:0 24px}

/* nav */
.nav{position:sticky;top:0;z-index:20;background:rgba(255,255,255,.85);backdrop-filter:blur(10px);
  border-bottom:1px solid var(--line)}
.nav-in{display:flex;align-items:center;justify-content:space-between;height:64px}
.brand{font-weight:800;font-size:20px;letter-spacing:.5px}
.brand .cap{color:var(--lg-cap)}
.brand .low{color:var(--lg-low)}
.links{display:flex;gap:22px;color:var(--muted);font-size:14px}
.links a:hover{color:var(--brand)}
.links a.active{color:var(--brand);font-weight:600}
@media(max-width:720px){.links{display:none}}

/* buttons */
.btn{display:inline-block;background:var(--brand);color:#fff;font-weight:600;padding:12px 22px;border-radius:10px;
  transition:transform .08s ease,background .15s ease}
.btn:hover{background:var(--brand2);transform:translateY(-1px)}
.btn-sm{padding:8px 16px;font-size:14px}
.btn-lg{padding:16px 30px;font-size:17px}
.btn-ghost{background:transparent;color:var(--brand);border:1px solid var(--brand)}
.btn-ghost:hover{background:rgba(24,95,165,.08)}

/* hero */
.hero{background:linear-gradient(160deg,#ffffff 0%,#eaf1f9 100%);padding:72px 0 64px;border-bottom:1px solid var(--line)}
.tag{display:inline-block;font-size:12px;color:var(--brand);background:rgba(24,95,165,.1);
  padding:4px 12px;border-radius:999px;font-weight:600;margin-bottom:18px}
.hero h1{font-size:42px;line-height:1.2;margin:0 0 16px;font-weight:800}
.hero h1 span{color:var(--brand)}
.lead{font-size:17px;color:var(--muted);max-width:680px;margin:0 0 28px}
.hero-cta{display:flex;gap:14px;flex-wrap:wrap}

/* sections */
.section{padding:64px 0}
.section.alt{background:var(--bg-alt)}
.sec-title{font-size:28px;font-weight:800;margin:0 0 36px;text-align:center}
.grid{display:grid;grid-template-columns:repeat(3,1fr);gap:20px}
@media(max-width:880px){.grid{grid-template-columns:repeat(2,1fr)}}
@media(max-width:560px){.grid{grid-template-columns:1fr}}
.card{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:24px;box-shadow:var(--shadow)}
.card .ico{font-size:30px;margin-bottom:10px}
.card h3{margin:0 0 8px;font-size:18px}
.card p{margin:0;color:var(--muted);font-size:14px}

/* download */
.dl-card{display:flex;align-items:center;justify-content:space-between;gap:24px;flex-wrap:wrap;
  background:var(--card);border:1px solid var(--line);border-radius:16px;padding:32px;box-shadow:var(--shadow)}
.dl-ver{font-size:22px;margin-bottom:12px}
.dl-ver strong{color:var(--brand)}
.dl-meta{list-style:none;padding:0;margin:0 0 14px;color:var(--muted);font-size:14px}
.dl-meta li{padding:3px 0}
.dl-note{font-size:13px;color:var(--muted);max-width:460px;margin:0}
.dl-note a{color:var(--brand);text-decoration:underline}
.dl-action{display:flex;flex-direction:column;gap:12px;align-items:flex-start}

/* changelog */
.log{max-width:720px;margin:0 auto}
.log-item{background:var(--card);border:1px solid var(--line);border-radius:12px;padding:20px 24px;box-shadow:var(--shadow)}
.log-ver{display:inline-block;font-weight:800;color:var(--brand);margin-right:10px}
.log-date{color:var(--muted);font-size:13px}
.log-item ul{margin:12px 0 0;padding-left:20px;color:var(--muted);font-size:14px}
.log-item li{padding:3px 0}

/* footer */
.foot{border-top:1px solid var(--line);background:#fff;padding:24px 0;color:var(--muted);font-size:13px}
.foot-in{display:flex;justify-content:space-between;align-items:center;flex-wrap:wrap;gap:10px}
.foot nav a{margin-left:18px}
.foot nav a:hover{color:var(--brand)}

/* language selector: show native names only, never country flags */
.lang-select{position:relative;display:inline-block;margin-left:12px}
.lang-current{display:inline-flex;align-items:center;gap:6px;background:#fff;border:1px solid var(--line);
  color:var(--ink);border-radius:9px;padding:7px 11px;cursor:pointer;font-size:14px;line-height:1.25;
  transition:border-color .15s ease,color .15s ease}
.lang-current:hover{border-color:var(--brand);color:var(--brand)}
.lang-current:focus-visible{outline:2px solid var(--brand);outline-offset:1px}
.lang-caret{font-size:10px;opacity:.55}
.lang-list{position:absolute;right:0;top:calc(100% + 6px);min-width:190px;max-height:340px;overflow:auto;z-index:60;
  list-style:none;margin:0;padding:4px;background:#fff;border:1px solid var(--line);border-radius:10px;
  box-shadow:0 10px 30px rgba(20,40,80,.16)}
.lang-list[hidden]{display:none}
.lang-opt{display:flex;align-items:center;gap:8px;padding:8px 10px;border-radius:7px;cursor:pointer;
  color:var(--ink);font-size:14px;line-height:1.25}
.lang-opt:hover{background:var(--bg-alt)}
.lang-opt.active{background:rgba(24,95,165,.12);color:var(--brand)}
.lang-opt .lang-name{white-space:nowrap}
[dir="rtl"] .lang-list{left:0;right:auto}

/* guestbook */
.gb-desc{color:var(--muted);font-size:15px;margin:0 0 22px;text-align:center}
.gb-form{max-width:680px;margin:0 auto 30px;display:flex;flex-direction:column;gap:10px}
.gb-name,.gb-msg{width:100%;background:#fff;border:1px solid var(--line);color:var(--ink);
  border-radius:10px;padding:11px 13px;font-size:14px;font-family:inherit;resize:vertical}
.gb-name:focus,.gb-msg:focus{outline:none;border-color:var(--brand)}
.gb-row{display:flex;align-items:center;justify-content:space-between;gap:12px}
.gb-hint{font-size:13px;color:var(--muted);min-height:18px}
.gb-hint.ok{color:var(--accent)}
.gb-hint.err{color:#c0392b}
.gb-list{max-width:680px;margin:0 auto;display:flex;flex-direction:column;gap:12px}
.gb-item{background:var(--card);border:1px solid var(--line);border-radius:12px;padding:14px 16px;box-shadow:var(--shadow)}
.gb-meta{display:flex;align-items:baseline;gap:10px;margin-bottom:6px}
.gb-author{font-weight:600;color:var(--ink);font-size:14px}
.gb-time{color:var(--muted);font-size:12px}
.gb-body{color:var(--ink);font-size:14px;line-height:1.65;white-space:pre-wrap;word-break:break-word}
.gb-empty{text-align:center}

/* ICP filing link (compliance) */
.foot .beian{color:var(--muted);text-decoration:none}
.foot .beian:hover{color:var(--brand)}