:root{
  --bg:#FFFFFF;
  --bg-raised:#FFFFFF;
  --bg-raised-2:#EFF6FF;
  --line:#DBEAFE;
  --text:#0F172A;
  --text-dim:#475569;
  --text-faint:#94A3B8;
  --accent:#0098F0;
  --accent-dim:#0077CC;
  --accent-glow:#0098F0;
  --green:#0284C7;
  --mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  --sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --dotop:0.04;
  --shadow:0 30px 60px -30px rgba(0,0,0,0.1);
  --nav-bg:rgba(248,250,252,0.88);
}
*{box-sizing:border-box;margin:0;padding:0;}
html{scroll-behavior:smooth;}
body{
  background:var(--bg);color:var(--text);
  font-family:var(--sans);line-height:1.6;
  -webkit-font-smoothing:antialiased;
}
body::before{
  content:'';position:fixed;inset:0;
  background-image:radial-gradient(circle at 1px 1px, rgba(128,110,90,var(--dotop)) 1px, transparent 0);
  background-size:28px 28px;pointer-events:none;z-index:0;
}
a{color:inherit;text-decoration:none;}
.wrap{max-width:1080px;margin:0 auto;padding:0 32px;position:relative;z-index:1;}
::selection{background:var(--accent);color:#FFFFFF;}

/* NAV */
nav{
  position:sticky;top:0;z-index:50;
  background:var(--nav-bg);backdrop-filter:blur(10px);
  border-bottom:1px solid var(--line);
}
nav .wrap{display:flex;align-items:center;justify-content:space-between;height:64px;}
.logo{
  font-family:var(--mono);font-weight:700;font-size:16px;
  display:flex;align-items:center;gap:10px;
}
.logo-icon{
  width:36px;height:36px;border-radius:8px;
  background:#FFFFFF;border:1px solid var(--line);
  display:flex;align-items:center;justify-content:center;
  box-shadow:0 2px 8px rgba(0,0,0,0.08);
}
.logo-icon img{display:block;}
.navlinks{display:flex;gap:36px;font-size:14px;color:var(--text-dim);}
.navlinks a:hover{color:var(--text);}
.nav-cta{
  font-family:var(--mono);font-size:13px;font-weight:500;
  background:var(--accent);color:#FFFFFF;
  padding:9px 18px;border-radius:6px;
  transition:background .15s ease;
}
.nav-cta:hover{background:var(--accent-glow);}
.nav-right{display:flex;align-items:center;gap:16px;}
.nav-github{display:inline-flex;align-items:center;justify-content:center;width:36px;height:36px;border-radius:6px;color:var(--text-dim);transition:color .15s ease,background .15s ease;}
.nav-github:hover{color:var(--text);background:var(--bg-raised-2);}
.nav-toggle{display:none;background:none;border:1px solid var(--line);width:36px;height:36px;border-radius:6px;font-size:18px;color:var(--text);cursor:pointer;flex-shrink:0;line-height:1;}
.nav-toggle:hover{border-color:var(--text-faint);}
@media(max-width:760px){
  nav .wrap{position:relative;}
  .nav-toggle{display:flex;align-items:center;justify-content:center;}
  .navlinks{
    display:none;
    position:absolute;top:64px;left:0;right:0;z-index:40;
    background:var(--bg-raised);
    border-bottom:1px solid var(--line);
    flex-direction:column;gap:0;
    padding:4px 0;
    box-shadow:0 12px 24px -12px rgba(0,0,0,0.12);
  }
  .navlinks.open{display:flex;}
  .navlinks a{padding:14px 32px;border-bottom:1px solid var(--line);font-size:15px;}
  .navlinks a:last-child{border-bottom:none;}
  .navlinks a:hover{background:var(--bg-raised-2);}
}

/* PAGE HEADER */
.page-header{padding:48px 0 32px;text-align:center;}
.page-header h1{
  font-family:var(--mono);font-size:clamp(28px,4vw,42px);
  font-weight:800;letter-spacing:-0.02em;
}
.page-header h1 .hl{color:var(--accent);}
.page-header p{margin-top:12px;color:var(--text-dim);font-size:17px;max-width:520px;margin-left:auto;margin-right:auto;}

/* TABS */
.tabs{
  display:flex;gap:4px;justify-content:center;flex-wrap:wrap;
  margin-bottom:40px;
  background:var(--bg-raised);border:1px solid var(--line);
  border-radius:12px;padding:6px;
  max-width:640px;margin-left:auto;margin-right:auto;
}
.tab-btn{
  font-family:var(--mono);font-size:13px;font-weight:500;
  padding:10px 20px;border-radius:8px;cursor:pointer;
  color:var(--text-dim);background:transparent;border:none;
  transition:all .15s ease;
}
.tab-btn:hover{color:var(--text);background:var(--bg-raised-2);}
.tab-btn.active{background:var(--accent);color:#FFFFFF;}

/* TUTORIAL CONTENT */
.tutorial-panel{display:none;}
.tutorial-panel.active{display:block;}

.step-list{max-width:720px;margin:0 auto;}
.step{
  background:var(--bg-raised);border:1px solid var(--line);
  border-radius:12px;padding:28px 32px;margin-bottom:16px;
  position:relative;
  transition:border-color .15s ease;
}
.step:hover{border-color:var(--text-faint);}
.step-num{
  position:absolute;top:-12px;left:28px;
  background:var(--accent);color:#FFFFFF;
  font-family:var(--mono);font-size:12px;font-weight:700;
  width:28px;height:28px;border-radius:50%;
  display:flex;align-items:center;justify-content:center;
}
.step h3{
  font-size:17px;font-weight:600;margin-bottom:10px;margin-top:4px;
  display:flex;align-items:center;gap:10px;
}
.step h3 svg{width:18px;height:18px;color:var(--accent);opacity:0.9;flex-shrink:0;}
.step p{font-size:14px;color:var(--text-dim);line-height:1.7;}
.step .note{
  margin-top:12px;padding:12px 16px;
  background:var(--bg-raised-2);border:1px solid var(--line);
  border-radius:8px;font-size:13px;color:var(--text-dim);
  display:flex;align-items:flex-start;gap:8px;
}
.step .note svg{width:16px;height:16px;color:var(--accent);flex-shrink:0;margin-top:2px;}
.step .code{
  margin-top:12px;padding:12px 16px;
  background:var(--bg-raised-2);border:1px solid var(--line);
  border-radius:8px;font-family:var(--mono);font-size:13px;
  color:var(--green);overflow-x:auto;
  word-break:break-all;
}
.step .btn-row{display:flex;gap:10px;margin-top:14px;flex-wrap:wrap;}
.step .btn-sm{
  font-family:var(--mono);font-size:13px;font-weight:500;
  padding:9px 18px;border-radius:6px;
  display:inline-flex;align-items:center;gap:8px;
  background:var(--accent);color:#FFFFFF;
  transition:background .15s ease;
}
.step .btn-sm:hover{background:var(--accent-glow);}
.step .btn-outline{
  background:transparent;border:1px solid var(--line);color:var(--text);
}
.step .btn-outline:hover{border-color:var(--text-faint);background:var(--bg-raised-2);}

/* Download address dropdown */
.dl-menu{position:relative;display:inline-block;}
.dl-trigger{border:none;cursor:pointer;}
.dl-caret{width:14px;height:14px;transition:transform .2s ease;}
.dl-menu.open .dl-caret{transform:rotate(180deg);}
.dl-list{
  position:absolute;top:calc(100% + 8px);left:0;z-index:30;
  min-width:200px;
  background:var(--bg-raised);border:1px solid var(--line);
  border-radius:10px;padding:6px;
  box-shadow:var(--shadow);
  display:none;flex-direction:column;gap:2px;
}
.dl-menu.open .dl-list{display:flex;}
.dl-item{
  font-family:var(--mono);font-size:13px;color:var(--text-dim);
  padding:10px 14px;border-radius:6px;
  transition:background .15s ease,color .15s ease;
}
.dl-item:hover{background:var(--bg-raised-2);color:var(--accent);}

/* Install method sub-tabs */
.install-tabs{
  display:grid;grid-template-columns:1fr 1fr;gap:12px;
  margin-bottom:24px;
}
.install-tab{
  background:var(--bg-raised);border:1.5px solid var(--line);
  border-radius:10px;padding:18px 20px;cursor:pointer;
  text-align:left;transition:all .2s ease;
  display:flex;flex-direction:column;gap:6px;
}
.install-tab:hover{border-color:var(--text-faint);}
.install-tab.active{
  border-color:var(--accent);
  background:var(--bg-raised-2);
  box-shadow:0 0 0 1px var(--accent), 0 4px 12px rgba(0,152,240,0.1);
}
.install-tab .tab-title{
  font-family:var(--mono);font-size:14px;font-weight:600;color:var(--text);
  display:flex;align-items:center;gap:8px;
}
.install-tab.active .tab-title{color:var(--accent);}
.install-tab .tab-title .radio{
  width:16px;height:16px;border-radius:50%;border:2px solid var(--line);
  display:flex;align-items:center;justify-content:center;flex-shrink:0;
  transition:border-color .15s ease;
}
.install-tab.active .tab-title .radio{border-color:var(--accent);}
.install-tab.active .tab-title .radio::after{
  content:'';width:8px;height:8px;border-radius:50%;background:var(--accent);
}
.install-tab .tab-desc{
  font-size:12px;color:var(--text-dim);line-height:1.5;
  padding-left:0;
}
.install-tab:disabled,.install-tab.disabled{
  opacity:0.55;cursor:not-allowed;
  background:var(--bg-raised);
}
.install-tab:disabled:hover,.install-tab.disabled:hover{border-color:var(--line);}
.tab-badge{
  margin-left:8px;font-family:var(--sans);font-size:11px;font-weight:500;
  color:var(--text-faint);background:var(--bg-raised-2);
  border:1px solid var(--line);border-radius:4px;padding:1px 6px;
}
.install-panel{display:none;}
.install-panel.active{display:block;}

/* FAQ */
.faq-section{padding:64px 0;border-top:1px solid var(--line);}
.faq-head{text-align:center;margin-bottom:40px;}
.faq-head h2{font-family:var(--mono);font-size:24px;font-weight:700;}
.faq-head p{color:var(--text-dim);margin-top:8px;font-size:15px;}
.faq-list{max-width:720px;margin:0 auto;}
.faq-item{
  border:1px solid var(--line);border-radius:10px;
  margin-bottom:12px;overflow:hidden;
  transition:border-color .15s ease;
}
.faq-item:hover{border-color:var(--text-faint);}
.faq-q{
  padding:18px 24px;cursor:pointer;
  font-size:15px;font-weight:600;
  display:flex;align-items:center;justify-content:space-between;gap:12px;
  user-select:none;
}
.faq-q .arrow{
  font-family:var(--mono);font-size:18px;color:var(--text-faint);
  transition:transform .2s ease;flex-shrink:0;
}
.faq-item.open .faq-q .arrow{transform:rotate(45deg);}
.faq-a{
  max-height:0;overflow:hidden;transition:max-height .3s ease;
  padding:0 24px;
}
.faq-item.open .faq-a{max-height:300px;padding:0 24px 18px;}
.faq-a p{font-size:14px;color:var(--text-dim);line-height:1.7;}

/* FOOTER */
footer{padding:48px 0;border-top:1px solid var(--line);}
footer .wrap{display:flex;justify-content:space-between;align-items:center;flex-wrap:wrap;gap:16px;}
.footer-meta{font-family:var(--mono);font-size:12px;color:var(--text-faint);}
.footer-links{display:flex;gap:24px;font-size:13px;color:var(--text-dim);}
.footer-links a:hover{color:var(--text);}

@media(max-width:600px){
  .wrap{padding:0 20px;}
  .step{padding:24px 20px;}
  .tabs{gap:2px;padding:4px;}
  .tab-btn{padding:8px 14px;font-size:12px;}
  footer .wrap{flex-direction:column;justify-content:center;align-items:center;text-align:center;gap:12px;}
}