:root{
  --blue-900:#1E3A8A; --blue-600:#2563EB; --sky:#38BDF8;
  --ink:#0F172A; --muted:#64748B; --bg:#FFFFFF; --soft:#F1F5F9; --line:#E2E8F0;
  --radius:16px; --maxw:1080px;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0; background:var(--bg); color:var(--ink);
  font-family:Inter,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,"PingFang SC","Microsoft YaHei",sans-serif;
  line-height:1.65; font-size:17px;
}
a{color:var(--blue-600); text-decoration:none}
a:hover{text-decoration:underline}
.container{max-width:var(--maxw); margin:0 auto; padding:0 22px}

header.site{position:sticky; top:0; z-index:20; background:rgba(255,255,255,.88); backdrop-filter:blur(8px); border-bottom:1px solid var(--line)}
.nav{display:flex; align-items:center; justify-content:space-between; height:70px}
.nav img{height:34px; display:block}
.nav ul{display:flex; gap:26px; list-style:none; margin:0; padding:0}
.nav a{color:var(--ink); font-weight:600; font-size:15px}
.nav a:hover{color:var(--blue-600); text-decoration:none}
.btn{display:inline-block; background:var(--blue-600); color:#fff; padding:12px 22px; border-radius:999px; font-weight:700; border:none; cursor:pointer}
.btn:hover{background:var(--blue-900); text-decoration:none}
.btn.ghost{background:transparent; color:var(--blue-600); border:2px solid var(--blue-600)}

.hero{padding:78px 0 60px; background:linear-gradient(180deg,#F8FAFF 0%,#FFFFFF 100%)}
.hero h1{font-size:clamp(30px,4.6vw,52px); line-height:1.15; margin:0 0 18px; letter-spacing:-.5px}
.hero p.lead{font-size:20px; color:var(--muted); max-width:640px; margin:0 0 30px}
.hero .cta{display:flex; gap:14px; flex-wrap:wrap}
.eyebrow{color:var(--sky); font-weight:800; letter-spacing:2px; text-transform:uppercase; font-size:13px; margin:0 0 12px}

section{padding:64px 0}
section.soft{background:var(--soft)}
h2{font-size:30px; margin:0 0 10px; letter-spacing:-.3px}
.sub{color:var(--muted); margin:0 0 34px}
.grid{display:grid; gap:22px}
.grid.three{grid-template-columns:repeat(3,1fr)}
.grid.two{grid-template-columns:repeat(2,1fr)}
@media(max-width:820px){.grid.three,.grid.two{grid-template-columns:1fr}}
.card{background:#fff; border:1px solid var(--line); border-radius:var(--radius); padding:26px}
.card h3{margin:0 0 8px; font-size:20px}
.card p{margin:0; color:var(--muted)}
.price{font-weight:800; color:var(--blue-900); font-size:15px; margin-top:14px; display:block}
.tag{display:inline-block; background:#E0F2FE; color:#0369A1; border-radius:999px; padding:4px 12px; font-size:13px; font-weight:700; margin-bottom:14px}

article.post{max-width:760px; margin:0 auto; padding:56px 22px}
article.post h1{font-size:38px; line-height:1.2; letter-spacing:-.5px; margin:0 0 12px}
article.post .meta{color:var(--muted); font-size:15px; margin-bottom:32px}
article.post h2{font-size:24px; margin:38px 0 10px}
article.post h3{font-size:19px; margin:26px 0 8px}
article.post ul,article.post ol{padding-left:22px}
article.post li{margin:6px 0}
article.post code{background:var(--soft); padding:2px 6px; border-radius:6px; font-size:15px}
blockquote{border-left:4px solid var(--sky); margin:22px 0; padding:6px 18px; background:#F8FAFF; color:#334155}

.list-post{display:flex; gap:20px; padding:22px 0; border-bottom:1px solid var(--line)}
.list-post .thumb{flex:0 0 96px; height:96px; border-radius:12px; background:linear-gradient(135deg,var(--blue-900),var(--sky)); display:flex; align-items:center; justify-content:center; color:#fff; font-weight:800; font-size:26px}
.list-post h3{margin:0 0 6px; font-size:21px}
.list-post p{margin:0; color:var(--muted); font-size:15px}

.calc{background:#fff; border:1px solid var(--line); border-radius:var(--radius); padding:26px; display:grid; grid-template-columns:1fr 1fr; gap:14px 26px}
@media(max-width:720px){.calc{grid-template-columns:1fr}}
.calc label{display:flex; flex-direction:column; font-weight:600; font-size:14px; gap:6px; color:#334155}
.calc input{border:1px solid var(--line); border-radius:10px; padding:11px 13px; font-size:16px; width:100%}
.calc input:focus{outline:2px solid var(--sky); border-color:var(--sky)}
.result{margin-top:26px; display:grid; grid-template-columns:repeat(3,1fr); gap:16px}
@media(max-width:720px){.result{grid-template-columns:1fr}}
.metric{background:var(--soft); border-radius:14px; padding:20px; text-align:center}
.metric .k{color:var(--muted); font-size:14px; font-weight:600}
.metric .v{font-size:30px; font-weight:800; margin-top:6px}
.metric .v.good{color:#059669}.metric .v.bad{color:#DC2626}

form.subscribe{display:flex; gap:10px; max-width:460px; flex-wrap:wrap}
form.subscribe input{flex:1; min-width:220px; border:1px solid var(--line); border-radius:10px; padding:13px 15px; font-size:16px}

footer.site{border-top:1px solid var(--line); padding:40px 0; color:var(--muted); font-size:14px}
footer.site .row{display:flex; justify-content:space-between; gap:16px; flex-wrap:wrap; align-items:center}
.note{font-size:14px; color:var(--muted); background:#FFFBEB; border:1px solid #FDE68A; border-radius:12px; padding:12px 16px}