.zk-hub{--zk-accent:#0284c7}.zk-hero{background:linear-gradient(#eef2ff,#fff);border-bottom:1px solid #e2e8f0;padding:28px 0 24px}.zk-hero-inner{max-width:960px;margin:0 auto;padding:0 16px}.zk-hero-crumbs{align-items:center;gap:6px;margin-bottom:14px;font-size:12px;display:flex}.zk-hero-crumbs a{color:#4338ca;text-decoration:none}.zk-hero-crumbs a:hover{text-decoration:underline}.zk-hero-crumbs .sep{color:#94a3b8}.zk-hero-crumbs .here{color:#334155;font-weight:600}.zk-hero-trust{color:#4338ca;background:#e0e7ff;border-radius:9999px;align-items:center;gap:6px;margin-bottom:14px;padding:4px 12px;font-size:12px;font-weight:600;display:inline-flex}.zk-hero-trust svg{width:13px;height:13px}.zk-hero-main{align-items:flex-start;gap:18px;display:flex}.zk-hero-emoji{flex-shrink:0;margin-top:4px;font-size:40px;line-height:1}.zk-hero h1{color:#0f172a;letter-spacing:-.025em;margin-bottom:14px;font-size:36px;font-weight:800;line-height:1.1}.zk-hero p{color:#475569;line-height:1.7}.zk-hero p.lead{margin-bottom:10px;font-size:15.5px}.zk-hero p.sub{color:#64748b;font-size:14px}.zk-hero p strong{color:#0f172a}.zk-hero p a{color:#4338ca;font-weight:600;text-decoration:none}.zk-hero p a:hover{text-decoration:underline}.zk-hero-stats{background:#e2e8f0;border:1px solid #e2e8f0;border-radius:14px;grid-template-columns:repeat(4,1fr);gap:1px;margin-top:24px;display:grid;overflow:hidden}.zk-hero-stat{text-align:left;color:inherit;background:#fff;padding:14px 16px;text-decoration:none}.zk-hero-stat-num{letter-spacing:-.02em;font-size:22px;font-weight:800;line-height:1}.zk-hero-stat-label{color:#0f172a;margin-top:4px;font-size:12px;font-weight:600}.zk-hero-stat-sub{color:#94a3b8;margin-top:2px;font-size:11px}.zk-hero-stat--link{cursor:pointer;transition:background .15s}.zk-hero-stat--link:hover{background:color-mix(in srgb, var(--zk-accent) 7%, #fff)}.zk-hero-stat--link .zk-hero-stat-sub{color:#4338ca;font-weight:700}.zk-jumpnav{z-index:30;-webkit-backdrop-filter:blur(8px);background:#f8fafceb;border-bottom:1px solid #e2e8f0;position:sticky;top:64px}.zk-jumpnav-inner{scrollbar-width:none;gap:8px;max-width:1152px;margin:0 auto;padding:10px 16px;display:flex;overflow-x:auto}.zk-jumpnav-inner::-webkit-scrollbar{display:none}.zk-jumpnav-pill{color:#475569;white-space:nowrap;cursor:pointer;background:#fff;border:1px solid #e2e8f0;border-radius:9999px;flex-shrink:0;align-items:center;gap:6px;padding:6px 12px;font-size:12px;font-weight:600;text-decoration:none;transition:background-color .15s,color .15s,border-color .15s;display:inline-flex}.zk-jumpnav-pill:hover{color:#1e293b;border-color:#cbd5e1}.zk-jumpnav-pill.is-active{color:#fff;background:#4f46e5;border-color:#4f46e5}.zk-section{margin:0 0 56px}.zk-section[id]{scroll-margin-top:120px}.zk-fade-in{animation:.24s forwards zk-fade-in}@keyframes zk-fade-in{0%{opacity:0;transform:translateY(6px)}to{opacity:1;transform:none}}.zk-section-header{margin-bottom:28px}.zk-section-eyebrow{letter-spacing:.1em;color:var(--zk-accent);background:linear-gradient(90deg, color-mix(in srgb, var(--zk-accent) 14%, transparent), color-mix(in srgb, var(--zk-accent) 4%, transparent));border:1px solid color-mix(in srgb, var(--zk-accent) 24%, transparent);border-radius:9999px;align-items:center;gap:6px;margin-bottom:14px;padding:4px 10px;font-size:10.5px;font-weight:700;display:inline-flex}.zk-section-eyebrow .icon{font-size:12px}.zk-section-titlerow{flex-wrap:wrap;justify-content:space-between;align-items:baseline;gap:12px;display:flex}.zk-section-h2{color:#0f172a;letter-spacing:-.02em;margin:0;padding-bottom:10px;font-size:26px;font-weight:800;line-height:1.15;position:relative}.zk-section-h2:after{content:"";background:linear-gradient(90deg, var(--zk-accent), color-mix(in srgb, var(--zk-accent) 33%, transparent) 70%, transparent);border-radius:2px;width:44px;height:3px;position:absolute;bottom:0;left:0}.zk-section-meta{flex-wrap:wrap;gap:8px;display:flex}.zk-section-meta-badge{color:#475569;background:#fff;border:1px solid #e2e8f0;border-radius:9999px;align-items:center;gap:5px;padding:5px 10px;font-size:11.5px;font-weight:600;display:inline-flex}.zk-section-sub{color:#64748b;max-width:700px;margin-top:10px;font-size:14px;line-height:1.6}.zk-section-sub em{color:#4338ca;font-style:normal;font-weight:600}.zk-ad{margin:0 0 56px}.zk-clusters{flex-direction:column;gap:26px;display:flex}.zk-cluster-head{align-items:center;gap:9px;margin-bottom:12px;display:flex}.zk-cluster-icon{background:color-mix(in srgb, var(--zk-accent) 12%, #fff);border:1px solid color-mix(in srgb, var(--zk-accent) 22%, transparent);border-radius:10px;justify-content:center;align-items:center;width:34px;height:34px;font-size:19px;line-height:1;display:inline-flex}.zk-cluster-name{color:#0f172a;letter-spacing:-.01em;font-size:15px;font-weight:800}.zk-fn-grid{grid-template-columns:repeat(auto-fill,minmax(216px,1fr));gap:12px;display:grid}.zk-fn{background:#fff;border:1px solid #e2e8f0;border-radius:14px;min-height:152px;padding:16px;text-decoration:none;transition:transform .3s cubic-bezier(.4,0,.2,1),box-shadow .3s cubic-bezier(.4,0,.2,1),border-color .3s;display:block;position:relative;overflow:hidden}.zk-fn:hover{border-color:color-mix(in srgb, var(--zk-accent) 35%, #e2e8f0);box-shadow:0 18px 30px -12px color-mix(in srgb, var(--zk-accent) 32%, transparent);transform:translateY(-3px)}.zk-fn-accent{background:linear-gradient(90deg, var(--zk-accent), transparent);transform-origin:0;opacity:.4;pointer-events:none;height:3px;transition:transform .4s cubic-bezier(.4,0,.2,1),opacity .4s;position:absolute;top:0;left:0;right:0;transform:scaleX(.25)}.zk-fn:hover .zk-fn-accent{opacity:1;transform:scaleX(1)}.zk-fn-tint{background:radial-gradient(circle, color-mix(in srgb, var(--zk-accent) 14%, transparent) 0%, transparent 70%);opacity:.55;pointer-events:none;width:120px;height:120px;transition:opacity .3s;position:absolute;top:-30px;right:-30px}.zk-fn:hover .zk-fn-tint{opacity:1}.zk-fn-glow{background:radial-gradient(circle, color-mix(in srgb, var(--zk-accent) 20%, transparent) 0%, transparent 65%);opacity:0;pointer-events:none;width:120px;height:120px;transition:opacity .3s;position:absolute;bottom:-25px;left:-25px}.zk-fn:hover .zk-fn-glow{opacity:1}.zk-fn-inner{z-index:1;flex-direction:column;height:100%;display:flex;position:relative}.zk-fn-top{justify-content:space-between;align-items:center;margin-bottom:10px;display:flex}.zk-fn-icon{font-size:26px;line-height:1}.zk-fn-name{color:#0f172a;align-items:center;gap:5px;margin-bottom:8px;font-size:15px;font-weight:700;line-height:1.25;transition:color .2s;display:inline-flex}.zk-fn:hover .zk-fn-title{color:var(--zk-accent)}.zk-fn-arrow{opacity:0;transition:opacity .28s,transform .28s;transform:translate(-4px)}.zk-fn:hover .zk-fn-arrow{opacity:1;transform:translate(0)}.zk-fn-sig{background:color-mix(in srgb, var(--zk-accent) 6%, #f8fafc);border:1px solid color-mix(in srgb, var(--zk-accent) 14%, transparent);border-radius:9px;flex-direction:column;gap:2px;margin-top:auto;padding:9px 11px;display:flex}.zk-fn-sig-en{color:#0f172a;font-size:12.5px;font-style:italic;font-weight:600;line-height:1.3}.zk-fn-sig-cz{color:#94a3b8;font-size:11.5px}.zk-reg{background:#fff;border:1px solid #e2e8f0;border-radius:18px;overflow:hidden;box-shadow:0 1px 2px #0f172a0a}.zk-reg-tabs{background:color-mix(in srgb, var(--zk-accent) 5%, #fff);border-bottom:1px solid #e2e8f0;flex-wrap:wrap;gap:8px;padding:14px 16px;display:flex}.zk-reg-tab{color:#475569;cursor:pointer;background:#fff;border:1.5px solid #e2e8f0;border-radius:9999px;align-items:center;gap:6px;padding:7px 13px;font-size:12.5px;font-weight:600;transition:background-color .15s,color .15s,border-color .15s;display:inline-flex}.zk-reg-tab:hover{border-color:#cbd5e1}.zk-reg-tab.is-active{background:var(--zk-accent);border-color:var(--zk-accent);color:#fff}.zk-reg-stage{padding:18px 16px}.zk-reg-panel[hidden]{display:none!important}.zk-reg-cols{grid-template-columns:repeat(3,1fr);gap:12px;display:grid}.zk-reg-col{background:#f8fafc;border:1px solid #e2e8f0;border-radius:12px;flex-direction:column;gap:9px;padding:14px;display:flex}.zk-reg-col--formal{border-top:3px solid #7c3aed}.zk-reg-col--neutral{border-top:3px solid #0ea5e9}.zk-reg-col--informal{border-top:3px solid #f59e0b}.zk-reg-tier{letter-spacing:.05em;text-transform:uppercase;color:#64748b;align-items:center;gap:5px;font-size:10.5px;font-weight:800;display:inline-flex}.zk-reg-col--formal .zk-reg-tier{color:#6d28d9}.zk-reg-col--neutral .zk-reg-tier{color:#0369a1}.zk-reg-col--informal .zk-reg-tier{color:#b45309}.zk-reg-phrase{align-items:center;gap:8px;display:flex}.zk-reg-en{color:#0f172a;font-size:15px;font-style:italic;font-weight:700;line-height:1.3}.zk-reg-phrase .pronounce-btn{color:var(--zk-accent);flex-shrink:0}.zk-reg-note{color:#475569;background:color-mix(in srgb, var(--zk-accent) 5%, #f8fafc);border:1px solid color-mix(in srgb, var(--zk-accent) 14%, transparent);border-radius:10px;margin-top:14px;padding:11px 13px;font-size:13px;line-height:1.55}.zk-pp-grid{grid-template-columns:repeat(auto-fill,minmax(288px,1fr));gap:14px;display:grid}.zk-pp-card{background:#fff;border:1px solid #e2e8f0;border-radius:14px;padding:16px;transition:box-shadow .2s,transform .2s}.zk-pp-card:hover{box-shadow:0 12px 24px -16px color-mix(in srgb, var(--zk-accent) 45%, transparent);transform:translateY(-2px)}.zk-pp-prompt{margin-bottom:12px}.zk-pp-bubble{background:color-mix(in srgb, var(--zk-accent) 12%, #fff);border:1px solid color-mix(in srgb, var(--zk-accent) 22%, transparent);color:#0f172a;border-radius:14px 14px 14px 4px;align-items:center;gap:7px;padding:8px 13px;font-size:14.5px;font-weight:700;display:inline-flex}.zk-pp-bubble .pronounce-btn{color:var(--zk-accent)}.zk-pp-q-cz{color:#94a3b8;margin-top:5px;margin-left:4px;font-size:11.5px;display:block}.zk-pp-answers{flex-direction:column;gap:7px;display:flex}.zk-pp-answer{background:#f8fafc;border:1px solid #e2e8f0;border-radius:4px 12px 12px;margin-left:16px;padding:8px 11px}.zk-pp-a-en{color:#0f172a;align-items:center;gap:7px;font-size:13.5px;font-weight:600;display:flex}.zk-pp-a-en .pronounce-btn{color:#15803d;flex-shrink:0}.zk-pp-a-cz{color:#94a3b8;margin-top:2px;font-size:11.5px;display:block}.zk-quiz{border:1px solid color-mix(in srgb, var(--zk-accent) 28%, #e2e8f0);box-shadow:0 12px 30px -18px color-mix(in srgb, var(--zk-accent) 50%, transparent);background:linear-gradient(135deg,#fff,#fff7ed);border-radius:18px;margin-bottom:24px;padding:20px}.zk-quiz-head{justify-content:space-between;align-items:center;margin-bottom:14px;display:flex}.zk-quiz-title{letter-spacing:.03em;text-transform:uppercase;color:var(--zk-accent);align-items:center;gap:6px;font-size:13px;font-weight:800;display:inline-flex}.zk-quiz-progress{color:#94a3b8;font-size:12px;font-weight:700}.zk-quiz-q{color:#0f172a;margin-bottom:14px;font-size:16px;font-weight:700}.zk-quiz-options{grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:10px;display:grid}.zk-quiz-opt{text-align:left;color:#0f172a;cursor:pointer;background:#fff;border:1.5px solid #e2e8f0;border-radius:12px;padding:13px 15px;font-size:14.5px;font-style:italic;font-weight:600;transition:border-color .15s,background-color .15s,transform .1s}.zk-quiz-opt:hover:not(:disabled){border-color:var(--zk-accent);background:color-mix(in srgb, var(--zk-accent) 5%, #fff)}.zk-quiz-opt:disabled{cursor:default}.zk-quiz-opt.is-correct{color:#15803d;background:#f0fdf4;border-color:#16a34a}.zk-quiz-opt.is-wrong{color:#b91c1c;background:#fef2f2;border-color:#dc2626}.zk-quiz-feedback{color:#475569;background:#fff;border:1px solid #e2e8f0;border-radius:12px;margin-top:14px;padding:13px 15px;font-size:13.5px;line-height:1.6}.zk-quiz-feedback strong{color:#0f172a}.zk-quiz-link{color:var(--zk-accent);white-space:nowrap;font-weight:700;text-decoration:none}.zk-quiz-link:hover{text-decoration:underline}.zk-quiz-foot{justify-content:space-between;align-items:center;min-height:20px;margin-top:14px;display:flex}.zk-quiz-score{color:#64748b;font-size:12.5px;font-weight:700}.zk-quiz-next{background:var(--zk-accent);color:#fff;cursor:pointer;border:none;border-radius:9999px;padding:9px 18px;font-size:13px;font-weight:700;transition:filter .15s}.zk-quiz-next:hover{filter:brightness(1.07)}.zk-traps{grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:14px;display:grid}.zk-trap{border:1px solid #e2e8f0;border-left:4px solid var(--zk-accent);background:#fff;border-radius:12px;padding:15px 17px;text-decoration:none;transition:box-shadow .2s,transform .2s;display:block}.zk-trap:hover{box-shadow:0 10px 22px -14px color-mix(in srgb, var(--zk-accent) 45%, transparent);transform:translateY(-2px)}.zk-trap-wrong{color:#b91c1c;margin-bottom:5px;font-size:13.5px;font-style:italic;line-height:1.4}.zk-trap-right{color:#15803d;font-size:13.5px;font-style:italic;font-weight:600;line-height:1.4}.zk-trap-why{color:#64748b;border-top:1px solid #f1f5f9;margin-top:9px;padding-top:9px;font-size:12.5px;line-height:1.5}.zk-faq{flex-direction:column;gap:10px;display:flex}.zk-faq-item{background:#fff;border:1px solid #e2e8f0;border-radius:12px;overflow:hidden}.zk-faq-q{color:#0f172a;cursor:pointer;padding:16px 44px 16px 18px;font-size:14.5px;font-weight:700;list-style:none;position:relative}.zk-faq-q::-webkit-details-marker{display:none}.zk-faq-q:after{content:"+";color:#94a3b8;font-size:20px;font-weight:400;position:absolute;top:50%;right:18px;transform:translateY(-50%)}.zk-faq-item[open] .zk-faq-q:after{content:"−"}.zk-faq-a{color:#475569;padding:0 18px 16px;font-size:13.5px;line-height:1.65}.zk-articles-grid{grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:24px;display:grid}.zk-back{text-align:center;margin-top:8px}.zk-back a{color:#4338ca;align-items:center;gap:8px;font-size:14px;font-weight:600;text-decoration:none;display:inline-flex}.zk-back a:hover{text-decoration:underline}@media (max-width:680px){.zk-hero h1{font-size:28px}.zk-hero-stats{grid-template-columns:repeat(2,1fr)}.zk-section-h2{font-size:22px}.zk-reg-cols{grid-template-columns:1fr}}@media (prefers-reduced-motion:reduce){.zk-fade-in{animation:none!important}.zk-fn,.zk-pp-card,.zk-trap,.zk-quiz-opt{transition:none!important}}