:root{--primary:#1769e0;--text:#172033;--muted:#667085;--border:#e5e7eb;--bg:#f7f9fc;--card:#fff;--shadow:0 10px 30px rgba(15,23,42,.07)}
*{box-sizing:border-box}html,body{margin:0;padding:0;overflow-x:hidden;font-family:Arial,Helvetica,sans-serif;color:var(--text);background:var(--bg)}
a{text-decoration:none;color:inherit}.container{width:min(1120px,92%);margin:auto}.site-header{background:#fff;border-bottom:1px solid var(--border);position:sticky;top:0;z-index:20}
.nav-wrap{min-height:72px;display:flex;align-items:center;gap:28px}.brand{font-size:1.2rem;font-weight:800;white-space:nowrap}.brand span{color:var(--primary)}
.nav-links{margin-left:auto;display:flex;align-items:center;gap:22px}.nav-links>a{font-weight:600;font-size:.92rem}.nav-links>a:hover,.nav-drop-btn:hover{color:var(--primary)}
.nav-dropdown{position:relative}.nav-drop-btn{border:0;background:transparent;color:var(--text);font:inherit;font-weight:600;cursor:pointer;padding:0}
.nav-dropdown-menu{position:absolute;top:calc(100% + 18px);left:50%;transform:translateX(-50%);min-width:235px;padding:8px;background:#fff;border:1px solid var(--border);border-radius:12px;box-shadow:var(--shadow);opacity:0;visibility:hidden;pointer-events:none}
.nav-dropdown-menu a{display:block;padding:9px 12px;border-radius:8px;font-size:.9rem}.nav-dropdown-menu a:hover{background:#edf3ff;color:var(--primary)}
.nav-dropdown:hover .nav-dropdown-menu,.nav-dropdown:focus-within .nav-dropdown-menu{opacity:1;visibility:visible;pointer-events:auto}.menu-toggle{display:none;border:0;background:none;font-size:1.5rem}
.article-hero{padding:54px 0 35px;background:linear-gradient(180deg,#eef5ff,#f7f9fc)}.article-hero h1{font-size:2.35rem;line-height:1.2;margin:0 0 12px}.meta{color:var(--muted);font-size:.9rem}
.layout{display:grid;grid-template-columns:minmax(0,1fr) 300px;gap:30px;padding:40px 0}.article,.side-card{background:#fff;border:1px solid var(--border);border-radius:15px;box-shadow:var(--shadow)}
.article{padding:30px}.article h2{font-size:1.35rem;margin:28px 0 10px}.article p,.article li{line-height:1.75;color:#334155}.article ul,.article ol{padding-left:23px}.tip{padding:18px;background:#f0f6ff;border-left:4px solid var(--primary);border-radius:8px;margin:24px 0}.ad{padding:28px;text-align:center;border:1px dashed #cfd6e2;color:#98a2b3;background:#fff;font-size:.75rem;letter-spacing:1.4px;margin:25px 0}
.side-card{padding:20px;margin-bottom:18px}.side-card h3{margin-top:0}.side-card a{display:block;padding:8px 0;color:#44506a;border-bottom:1px solid #f0f2f5;font-size:.9rem}.side-card a:hover{color:var(--primary)}
.site-footer{background:#111827;color:#cbd5e1;padding:40px 0}.footer-grid{display:grid;grid-template-columns:2fr 1fr 1fr 1fr;gap:30px}.site-footer h3{color:#fff;margin-top:0}.site-footer a{display:block;margin:8px 0;color:#cbd5e1;font-size:.9rem}.copyright{border-top:1px solid #2c3545;margin-top:28px;padding-top:18px;font-size:.85rem;color:#94a3b8}
@media(max-width:900px){.menu-toggle{display:block;margin-left:auto}.nav-links{display:none;position:absolute;top:64px;left:0;right:0;background:#fff;padding:18px;flex-direction:column;gap:14px;border-bottom:1px solid var(--border)}.nav-links.mobile-open{display:flex}.nav-dropdown{width:100%;text-align:center}.nav-drop-btn{padding:5px 0}.nav-dropdown-menu{position:static;transform:none;display:none;opacity:1;visibility:visible;pointer-events:auto;box-shadow:none;border:0}.nav-dropdown-menu.open{display:block}.layout{grid-template-columns:1fr}.article{padding:22px}.article-hero h1{font-size:2rem}.footer-grid{grid-template-columns:repeat(2,1fr)}}
@media(max-width:600px){.footer-grid{grid-template-columns:1fr}}

.article-nav{display:flex;justify-content:space-between;gap:15px;align-items:center;margin:24px 0;padding:14px 16px;border:1px solid var(--border);border-radius:10px;background:#f8fafc}.article-nav a{color:var(--primary);font-weight:700}.article-nav span{display:flex;gap:15px}@media(max-width:600px){.article-nav{flex-direction:column;align-items:flex-start}}