:root{--ink:#14213d;--blue:#1b4d8c;--sky:#e8f1fb;--teal:#0f8b8d;--bg:#ffffff;--muted:#5b6472;--line:#e3e8ef;--warn:#fff4e5}
*{box-sizing:border-box}html{scroll-behavior:smooth}
body{margin:0;font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;color:var(--ink);background:var(--bg);line-height:1.65;font-size:17px}
a{color:var(--blue)}a:hover{color:var(--teal)}
.wrap{max-width:1100px;margin:0 auto;padding:0 22px}
header{border-bottom:1px solid var(--line);background:#fff;position:sticky;top:0;z-index:10}
.top{display:flex;align-items:center;justify-content:space-between;gap:20px;padding:14px 22px}
.logo{font-family:Georgia,"Times New Roman",serif;font-weight:900;font-size:22px;text-decoration:none;color:var(--ink)}
.logo span{color:var(--teal)}
nav ul{list-style:none;margin:0;padding:0;display:flex;flex-wrap:wrap;gap:4px 16px}
nav a{text-decoration:none;font-size:15px;color:var(--ink);padding:4px 0;border-bottom:2px solid transparent}
nav a:hover,nav a.active{border-color:var(--teal);color:var(--teal)}
.hero{background:linear-gradient(120deg,var(--sky),#f6fbff);padding:52px 0 40px;border-bottom:1px solid var(--line)}
.hero h1{font-family:Georgia,"Times New Roman",serif;font-size:clamp(28px,4vw,42px);line-height:1.2;margin:0 0 14px;max-width:820px}
.hero p{max-width:760px;font-size:19px;color:var(--muted);margin:0 0 20px}
.btn{display:inline-block;background:var(--teal);color:#fff!important;text-decoration:none;font-weight:700;padding:12px 22px;border-radius:8px}
.btn.ghost{background:#fff;color:var(--teal)!important;border:2px solid var(--teal)}
main{padding:40px 0 60px}
.grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:18px}
.card{border:1px solid var(--line);border-radius:12px;padding:20px;background:#fff;box-shadow:0 2px 10px rgba(20,33,61,.04)}
.card h3{margin:0 0 6px;font-size:19px}.card p{margin:0;color:var(--muted);font-size:15px}
.card a.more{display:inline-block;margin-top:10px;font-weight:700;text-decoration:none}
article{max-width:800px}
article h2{font-family:Georgia,"Times New Roman",serif;font-size:26px;margin:40px 0 12px;line-height:1.25}
article h3{font-size:20px;margin:26px 0 8px}
article p{margin:0 0 16px}
.lead{font-size:19px;color:var(--muted)}
.box{background:var(--sky);border-left:4px solid var(--teal);padding:16px 20px;border-radius:0 10px 10px 0;margin:22px 0}
.warn{background:var(--warn);border-left-color:#e0a030}
table{width:100%;border-collapse:collapse;font-size:15px;margin:16px 0 24px}
th,td{text-align:left;padding:10px 12px;border-bottom:1px solid var(--line);vertical-align:top}
th{background:var(--sky);font-weight:700}
.tbl{overflow-x:auto}
.prod{display:flex;gap:16px;align-items:center;border:1px solid var(--line);border-radius:12px;padding:14px 16px;margin:12px 0;text-decoration:none;color:var(--ink);background:#fff}
.prod:hover{border-color:var(--teal)}
.prod .t{font-weight:700}.prod .d{font-size:14px;color:var(--muted)}.prod .pr{margin-left:auto;white-space:nowrap;font-weight:700;color:var(--teal)}
.toc{border:1px solid var(--line);border-radius:12px;padding:16px 22px;margin:20px 0 30px;background:#fafcff}
.toc ol{margin:8px 0 0;padding-left:20px;columns:2;column-gap:30px;font-size:15px}
.toc a{text-decoration:none}
.side{margin-top:50px;border-top:1px solid var(--line);padding-top:24px}
.side h4{margin:0 0 10px;font-size:14px;letter-spacing:.08em;text-transform:uppercase;color:var(--muted)}
.side ul{margin:0;padding-left:18px;font-size:15px}
.faq details{border:1px solid var(--line);border-radius:10px;padding:12px 16px;margin:8px 0}
.faq summary{font-weight:700;cursor:pointer}
footer{background:var(--ink);color:#c9d3e3;padding:36px 0;font-size:14px}
footer a{color:#fff}
footer .cols{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:24px}
footer h4{color:#fff;margin:0 0 8px}
footer ul{list-style:none;margin:0;padding:0}footer li{margin:4px 0}
.calc{background:#fafcff;border:1px solid var(--line);border-radius:12px;padding:20px}
.calc label{display:block;font-size:14px;color:var(--muted);margin:10px 0 4px}
.calc input,.calc select{width:100%;padding:9px 10px;border:1px solid var(--line);border-radius:8px;font-size:16px}
.calc .row{display:grid;grid-template-columns:repeat(auto-fit,minmax(160px,1fr));gap:12px}
.calc .res{margin-top:16px;font-size:20px;font-weight:700;color:var(--teal)}
.small{font-size:13px;color:var(--muted)}
.author{display:flex;gap:16px;align-items:flex-start;background:#fafcff;border:1px solid var(--line);border-radius:12px;padding:16px 18px;margin:36px 0 0;font-size:15px}.author img{width:64px;height:64px;border-radius:50%;object-fit:cover;background:#dfe7f1}

.crumbs{font-size:13px;color:var(--muted);margin:0 0 10px}.crumbs a{color:var(--muted);text-decoration:none}.crumbs a:hover{color:var(--teal)}
.meta{font-size:13px;color:var(--muted);margin:14px 0 0;display:flex;gap:14px;flex-wrap:wrap}
.hero{position:relative;overflow:hidden}.hero .art{position:absolute;right:22px;top:50%;transform:translateY(-50%);width:300px;opacity:.9}
@media(max-width:1000px){.hero .art{display:none}}
.hero .wrap{position:relative;z-index:1}
figure img{aspect-ratio:2/1;object-fit:cover;background:var(--sky)}
.card{transition:transform .15s,box-shadow .15s}.card:hover{transform:translateY(-2px);box-shadow:0 8px 24px rgba(20,33,61,.08)}
.card .ic{width:44px;height:44px;margin-bottom:10px}
.navtoggle{display:none}.burger{display:none;cursor:pointer;width:34px;height:34px;border:1px solid var(--line);border-radius:8px;align-items:center;justify-content:center}
.burger span{display:block;width:18px;height:2px;background:var(--ink);box-shadow:0 -6px 0 var(--ink),0 6px 0 var(--ink)}
@media(max-width:860px){.burger{display:flex}nav{display:none;width:100%}nav ul{flex-direction:column;gap:2px;padding:8px 0 12px}nav a{display:block;padding:8px 0;border-bottom:1px solid var(--line)}.navtoggle:checked~nav{display:block}.top{flex-wrap:wrap}}
.cta-box{background:var(--ink);color:#fff;border-radius:14px;padding:24px 26px;margin:36px 0 0}.cta-box a{color:#9fd8d9}.cta-box h3{margin:0 0 6px;color:#fff}
.skip{position:absolute;left:-9999px}.skip:focus{left:10px;top:10px;background:#fff;padding:8px;z-index:99}
@media(max-width:700px){.toc ol{columns:1}.prod{flex-wrap:wrap}.prod .pr{margin-left:0}.hero{padding:34px 0 28px}}
@media print{header,footer,.hero .btn{display:none}}