:root{
  --bg:#f3f4fb;--card:#fff;--ink:#1e1b4b;--txt:#373557;--mut:#7c7a99;--line:#e4e5f2;
  --in:#4338ca;--in2:#6366f1;--am:#fbbf24;--am-bg:#fff7e0;--ok:#059669;--bad:#dc2626;
  --r:18px;--f:"Rubik",system-ui,sans-serif;--shadow:0 1px 2px rgba(30,27,75,.05),0 8px 24px rgba(30,27,75,.06)
}
*,*::before,*::after{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:80px}
body{margin:0;background:var(--bg);color:var(--txt);font:400 16.5px/1.68 var(--f)}
img{max-width:100%;height:auto;display:block}
a{color:var(--in)}
.db-app{display:grid;grid-template-columns:260px minmax(0,1fr);min-height:100vh}
/* left app sidebar */
.db-side{position:sticky;top:0;height:100vh;overflow-y:auto;background:linear-gradient(180deg,#312e81,#1e1b4b);color:#c7d2fe;padding:26px 18px;display:flex;flex-direction:column;gap:6px}
.db-logo svg{display:block;width:176px;height:auto;margin:0 0 26px 6px}
.db-side-cap{font-size:.7rem;letter-spacing:.14em;text-transform:uppercase;color:#818cf8;margin:0 0 6px 10px}
.db-side-nav{display:flex;flex-direction:column;gap:4px}
.db-side-link{display:flex;align-items:center;gap:12px;padding:11px 12px;border-radius:12px;color:#e0e7ff;text-decoration:none;font-weight:500;font-size:.95rem;transition:background .2s}
.db-side-link:hover{background:rgba(255,255,255,.08)}
.db-side-link[aria-current]{background:var(--am);color:var(--ink)}
.db-side-brand{margin-top:auto;background:rgba(255,255,255,.06);border-radius:14px;padding:14px;display:flex;flex-direction:column;gap:8px;font-size:.82rem}
.db-side-brand img{width:110px;background:#0b0b14;border-radius:8px;padding:6px}
.db-side-age{font-size:.8rem;margin:12px 0 0 6px}
.db-side-age b{background:var(--am);color:var(--ink);border-radius:6px;padding:2px 6px;margin-right:6px}
/* top bar */
.db-top{position:sticky;top:0;z-index:20;display:flex;align-items:center;gap:14px;padding:12px 32px;background:rgba(243,244,251,.9);backdrop-filter:blur(10px);border-bottom:1px solid var(--line)}
.db-top-logo{display:none}
.db-top-date{color:var(--mut);font-size:.88rem}
.db-top-age{margin-left:auto;font-weight:700;font-size:.8rem;color:var(--in);border:1.5px solid var(--in);border-radius:8px;padding:3px 8px}
.db-menu-btn{display:none;align-items:center;gap:6px;background:var(--in);color:#fff;border:0;border-radius:12px;padding:9px 14px;font:500 .9rem var(--f);cursor:pointer}
.db-mainwrap{min-width:0}
.db-main{max-width:980px;padding:26px 32px 40px}
/* cards */
.db-card{background:var(--card);border-radius:var(--r);box-shadow:var(--shadow);padding:26px 30px;margin-bottom:18px;border:1px solid var(--line)}
.db-crumbs{font-size:.85rem;color:var(--mut);margin:0 0 10px}
.db-crumbs a{color:var(--mut)}
.db-hero h1{font-size:clamp(1.6rem,3vw,2.35rem);line-height:1.2;color:var(--ink);margin:0 0 14px;font-weight:700}
.db-chips{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:18px}
.db-chip{font-size:.8rem;background:var(--bg);border:1px solid var(--line);border-radius:999px;padding:4px 12px;color:var(--mut)}
.db-chip--author{background:#eef2ff;color:var(--in);border-color:#c7d2fe;font-weight:500}
.db-chip--hot{background:var(--am-bg);color:#92400e;border-color:#fde68a}
.db-banner{margin:0 0 18px;border-radius:14px;overflow:hidden}
.db-banner img{width:100%;aspect-ratio:21/9;object-fit:cover;object-position:top}
.db-lead{font-size:1.1rem;color:var(--ink);margin:0;padding-left:16px;border-left:4px solid var(--am)}
/* sticky subnav */
.db-subnav{position:sticky;top:57px;z-index:10;display:flex;gap:6px;overflow-x:auto;background:var(--card);border:1px solid var(--line);border-radius:14px;padding:8px;margin-bottom:18px;box-shadow:var(--shadow);scrollbar-width:thin}
.db-subnav span{flex:none;font-size:.78rem;color:var(--mut);padding:6px 6px 6px 8px;text-transform:uppercase;letter-spacing:.06em}
.db-subnav a{flex:none;font-size:.82rem;text-decoration:none;color:var(--txt);background:var(--bg);border-radius:10px;padding:6px 12px;white-space:nowrap;transition:.2s}
.db-subnav a:hover,.db-subnav a.on{background:var(--in);color:#fff}
/* body */
.db-article{counter-reset:h}
.db-card h2{counter-increment:h;display:flex;gap:14px;align-items:center;font-size:1.4rem;line-height:1.3;color:var(--ink);margin:0 0 16px;font-weight:700}
.db-card h2::before{content:counter(h);flex:none;display:grid;place-items:center;width:38px;height:38px;border-radius:11px;background:linear-gradient(135deg,var(--in),var(--in2));color:#fff;font-size:1rem}
.db-card h3{font-size:1.08rem;color:var(--ink);margin:20px 0 8px;font-weight:600}
.db-card p{margin:0 0 .95em}
.db-card p:last-child{margin-bottom:0}
.db-card ul,.db-card ol{padding-left:1.25em;margin:0 0 1em}
.db-card li{margin-bottom:.35em}
.db-card li::marker{color:var(--in)}
.db-card strong{color:var(--ink);font-weight:600}
.tbl-wrap{overflow-x:auto;margin:0 0 1em;border-radius:12px;border:1px solid var(--line)}
.tbl-wrap table{width:100%;border-collapse:collapse;min-width:540px;font-size:.93rem}
.tbl-wrap th{background:#eef2ff;color:var(--ink);text-align:left;padding:10px 14px;font-weight:600}
.tbl-wrap td{padding:10px 14px;border-top:1px solid var(--line)}
.tbl-wrap tr:nth-child(even) td{background:#fafaff}
.db-fig{margin:18px 0 0}
.db-fig img{border-radius:12px;border:1px solid var(--line)}
.db-fig figcaption{font-size:.84rem;color:var(--mut);margin-top:8px}
/* calc */
.db-calc{margin:18px 0 0;background:var(--am-bg);border:1px solid #fde68a;border-radius:16px;padding:20px}
.db-calc-title{font-weight:700;color:var(--ink);font-size:1.15rem;margin:0 0 12px}
.db-calc-fields{display:grid;grid-template-columns:repeat(3,1fr);gap:12px}
.db-calc-f{display:flex;flex-direction:column;gap:5px;font-size:.82rem;color:#92400e}
.db-calc input{font:600 1.05rem var(--f);border:1.5px solid #fcd34d;border-radius:12px;padding:10px 12px;background:#fff;color:var(--ink);width:100%}
.db-calc input:focus{outline:3px solid rgba(67,56,202,.25);border-color:var(--in)}
.db-calc-out{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin:14px 0 10px}
.db-calc-out div{background:#fff;border-radius:12px;padding:12px 14px}
.db-calc-out span{display:block;font-size:.78rem;color:var(--mut)}
.db-calc-out b{font-size:1.3rem;color:var(--ok)}
.db-calc-out b.is-neg{color:var(--bad)}
.db-calc-note{font-size:.8rem;color:#92400e;margin:0}
/* FAQ */
.db-acc{border:1px solid var(--line);border-radius:14px;margin-bottom:10px;overflow:hidden;transition:box-shadow .2s}
.db-acc.open{box-shadow:0 6px 18px rgba(67,56,202,.12);border-color:#c7d2fe}
.db-acc button{width:100%;display:flex;justify-content:space-between;align-items:center;gap:14px;text-align:left;background:#fff;border:0;padding:15px 18px;font:500 1rem/1.4 var(--f);color:var(--ink);cursor:pointer}
.db-acc svg{flex:none;color:var(--in);transition:transform .25s}
.db-acc.open svg{transform:rotate(90deg)}
.db-acc-body{display:none;padding:0 18px 16px}
.db-acc.open .db-acc-body{display:block}
.db-acc-body p{margin:0}
.db-legal{font-size:.85rem;color:var(--mut);background:#fff;border:1px dashed var(--line);border-radius:14px;padding:14px 18px}
.db-legal p{margin:0}
/* bottom: chips + related */
.db-more{margin-top:30px}
.db-more-t{font-weight:700;color:var(--ink);font-size:1.2rem;margin:0 0 12px}
.db-chiprow{display:flex;flex-wrap:wrap;gap:10px;margin-bottom:18px}
.db-chiprow a{display:inline-flex;align-items:center;gap:8px;background:#fff;border:1.5px solid #c7d2fe;color:var(--in);text-decoration:none;border-radius:999px;padding:8px 16px;font-weight:500;font-size:.92rem}
.db-chiprow a:hover{background:var(--in);color:#fff;border-color:var(--in)}
.db-relgrid{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}
.db-rel{background:#fff;border-radius:14px;overflow:hidden;box-shadow:var(--shadow);text-decoration:none;color:var(--ink);font-weight:500;font-size:.93rem;line-height:1.35}
.db-rel img{aspect-ratio:16/10;object-fit:cover;object-position:top;width:100%}
.db-rel span{display:block;padding:12px 14px}
.db-rel:hover span{color:var(--in)}
/* footer 4-col */
.db-foot{background:#fff;border-top:1px solid var(--line);margin-top:20px}
.db-foot-grid{display:grid;grid-template-columns:1.3fr 1fr 1.2fr 1fr;gap:28px;padding:34px 32px 20px;font-size:.88rem;color:var(--mut)}
.db-foot-logo{width:150px;margin-bottom:10px}
.db-foot-t{font-weight:600;color:var(--ink);margin:0 0 10px}
.db-foot-grid a{display:block;color:var(--txt);text-decoration:none;margin-bottom:6px}
.db-foot-grid a:hover{color:var(--in)}
.db-foot-grid p{margin:0 0 8px}
.db-foot-bar{display:flex;justify-content:space-between;align-items:center;flex-wrap:wrap;gap:14px;padding:16px 32px 24px;border-top:1px solid var(--line);font-size:.85rem;color:var(--mut)}
.db-badges{display:flex;gap:8px;flex-wrap:wrap}
.db-badges img{height:32px;width:auto}
/* bottom sheet */
.db-sheet{position:fixed;inset:0;z-index:60;pointer-events:none}
.db-sheet-bg{position:absolute;inset:0;background:rgba(30,27,75,.4);opacity:0;transition:opacity .3s}
.db-sheet-panel{position:absolute;left:0;right:0;bottom:0;background:#fff;border-radius:24px 24px 0 0;padding:10px 20px 24px;transform:translateY(105%);transition:transform .35s cubic-bezier(.2,.8,.2,1);max-height:85vh;overflow-y:auto}
.db-sheet.open{pointer-events:auto}
.db-sheet.open .db-sheet-bg{opacity:1}
.db-sheet.open .db-sheet-panel{transform:none}
.db-sheet-handle{display:block;width:44px;height:5px;border-radius:3px;background:#d4d4e8;margin:0 auto 16px;cursor:pointer}
.db-sheet-t{font-size:.75rem;letter-spacing:.12em;text-transform:uppercase;color:var(--mut);margin:0 0 8px}
.db-sheet-nav{display:grid;grid-template-columns:1fr 1fr;gap:10px}
.db-sheet-link{display:flex;flex-direction:column;gap:8px;padding:16px;border-radius:16px;background:var(--bg);color:var(--ink);text-decoration:none;font-weight:500;font-size:.92rem}
.db-sheet-link svg{color:var(--in)}
.db-sheet-link[aria-current]{background:var(--in);color:#fff}
.db-sheet-link[aria-current] svg{color:var(--am)}
.db-sheet-x{margin-top:16px;width:100%;border:0;background:var(--bg);border-radius:14px;padding:12px;font:500 .95rem var(--f);color:var(--ink);cursor:pointer}
.db-up{position:fixed;right:20px;bottom:20px;z-index:30;width:48px;height:48px;border-radius:14px;border:0;background:var(--am);color:var(--ink);box-shadow:0 8px 20px rgba(251,191,36,.45);cursor:pointer;display:grid;place-items:center;opacity:0;visibility:hidden;transform:scale(.8);transition:.25s}
.db-up.show{opacity:1;visibility:visible;transform:none}
@media (max-width:1060px){
  .db-app{grid-template-columns:minmax(0,1fr)}
  .db-side{display:none}
  .db-top-logo{display:block}
  .db-top-logo img{width:140px}
  .db-top-date{display:none}
  .db-top-age{margin-left:auto}
  .db-menu-btn{display:inline-flex}
  .db-main{margin:0 auto}
}
@media (max-width:700px){
  .db-top{padding:10px 14px}
  .db-main{padding:16px 12px 30px}
  .db-card{padding:20px 18px;border-radius:16px}
  .db-subnav{top:53px}
  .db-calc-fields,.db-calc-out{grid-template-columns:1fr}
  .db-relgrid{grid-template-columns:1fr}
  .db-foot-grid{grid-template-columns:1fr 1fr;padding:26px 16px 14px}
  .db-foot-grid>div:first-child{grid-column:1/-1}
  .db-foot-bar{padding:14px 16px 22px}
  .db-card h2{font-size:1.22rem}
  .db-card h2::before{width:32px;height:32px;border-radius:9px;font-size:.9rem}
}