:root{--ink:#182433;--blue:#1f4e79;--blue2:#2e74b5;--pale:#eef4fa;--line:#d7e1ea;--muted:#5b6b7b;--white:#fff}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;font-family:Inter,Segoe UI,Arial,sans-serif;color:var(--ink);background:#f6f8fb;line-height:1.58}
a{color:var(--blue2)}.wrap{width:min(1180px,calc(100% - 32px));margin:auto}.hero{background:linear-gradient(135deg,#102f4d,#1f4e79 62%,#2e74b5);color:#fff;padding:64px 0 52px}
.eyebrow{letter-spacing:.12em;text-transform:uppercase;font-size:.78rem;font-weight:800;opacity:.78}.hero h1{font-size:clamp(2rem,5vw,4.1rem);line-height:1.05;margin:.35rem 0 1rem;max-width:980px}.hero p{max-width:820px;font-size:1.08rem;opacity:.94}
.actions{display:flex;gap:12px;flex-wrap:wrap;margin-top:24px}.btn{display:inline-block;padding:11px 17px;border-radius:9px;text-decoration:none;font-weight:750;background:#fff;color:var(--blue)}.btn.alt{background:transparent;color:#fff;border:1px solid rgba(255,255,255,.55)}
.meta{background:#fff;border-bottom:1px solid var(--line)}.meta .wrap{display:grid;grid-template-columns:repeat(4,1fr);gap:16px;padding:18px 0}.meta b{display:block;color:var(--blue)}.meta span{color:var(--muted);font-size:.92rem}
main{padding:38px 0 72px}.intro,.part{background:#fff;border:1px solid var(--line);border-radius:14px;padding:24px;margin-bottom:24px}.intro h2,.part h2{color:var(--blue);margin-top:0}.route{display:grid;grid-template-columns:repeat(4,1fr);gap:12px}.route a{background:var(--pale);border:1px solid var(--line);padding:12px;border-radius:9px;text-decoration:none;font-weight:700}
.chapters{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px}.chapter{background:#fff;border:1px solid var(--line);border-radius:12px;padding:20px;scroll-margin-top:20px}.chapter-top{display:flex;justify-content:space-between;gap:12px;align-items:center}.num{font-size:1.55rem;font-weight:900;color:var(--blue2)}.status{font-size:.78rem;color:var(--muted);background:var(--pale);padding:4px 8px;border-radius:999px;text-align:right}.chapter h3{font-size:1.2rem;line-height:1.25;color:var(--blue);margin:.45rem 0 1rem}.chapter p{margin:.55rem 0}.boundary{border-left:4px solid var(--blue2);padding-left:10px;background:var(--pale)}
.footer{background:#12283d;color:#dce8f2;padding:28px 0}.footer a{color:#fff}@media(max-width:820px){.meta .wrap,.route,.chapters{grid-template-columns:1fr}.hero{padding-top:42px}.chapter-top{align-items:flex-start}}

.example-steps{columns:2;column-gap:28px;padding-left:24px}.example-steps li{break-inside:avoid;margin:0 0 10px}
.example{margin-top:12px;border:1px solid #e3cf91;background:#fff8e7;border-radius:9px;padding:9px 12px}.example summary{cursor:pointer;color:#7a5a00;font-weight:800}.example p{margin:.65rem 0 0}
@media(max-width:820px){.example-steps{columns:1}}