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figcaption{margin:12px 4px 0;color:#94948e;font:9px Courier New,monospace;letter-spacing:.03em}.osi-explorer{display:grid;grid-template-columns:.9fr 1.4fr;gap:1px;margin-top:60px;border:1px solid var(--basic-line);background:var(--basic-line)}.layer-list{display:flex;flex-direction:column;gap:1px;background:var(--basic-line)}.layer-button{display:grid;grid-template-columns:34px 1fr auto;align-items:center;gap:10px;min-height:52px;padding:0 18px;border:0;color:var(--basic-ink);background:var(--basic-paper);text-align:left;cursor:pointer;font-family:inherit}.layer-button:hover,.layer-button.is-selected{color:#fff;background:var(--basic-orange)}.layer-button>span{color:#888880;font:10px Courier New,monospace}.layer-button:hover>span,.layer-button.is-selected>span{color:#76250f}.layer-button strong{font-size:13px}.layer-button small{color:#8a8a84;font:10px Courier New,monospace}.layer-button:hover small,.layer-button.is-selected 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button.is-active{color:#fff;background:var(--ipv4-orange);border-color:var(--ipv4-orange)}.bit-display{margin-top:42px}.bit-address{display:flex;justify-content:space-between;align-items:center;border-bottom:1px solid var(--ipv4-line);padding-bottom:10px}.bit-address span{color:#777770;font:9px Courier New,monospace}.bit-address strong{font:14px Courier New,monospace}.bit-octets{display:flex;align-items:center;justify-content:space-between;gap:5px;padding:26px 0 17px;overflow-x:auto}.bit-octet{display:grid;grid-template-columns:repeat(8,1fr);flex:1;min-width:100px}.bit-octet span{padding:8px 0;text-align:center;font:16px Courier New,monospace}.bit-octet .network-bit{color:#fff;background:var(--ipv4-orange)}.bit-octet .host-bit{color:#55554f;background:#deded9}.bit-octets>i{color:#777770;font-style:normal;font-size:18px}.bit-legend{display:flex;flex-wrap:wrap;gap:18px;align-items:center;color:#777770;font-size:10px}.bit-legend span{display:inline-flex;align-items:center;gap:5px}.bit-legend b{width:9px;height:9px;display:inline-block}.network-key{background:var(--ipv4-orange)}.host-key{background:#deded9}.bit-legend strong{margin-left:auto;color:var(--ipv4-orange);font:10px Courier New,monospace}.calculator-section{display:grid;grid-template-columns:.9fr 1.4fr;gap:80px;background:#ecece8}.calculator-panel{padding:24px;background:var(--ipv4-paper);border:1px solid var(--ipv4-line)}.calculator-panel label{display:block;margin-bottom:8px;color:#777770;font:9px Courier New,monospace;text-transform:uppercase}.calculator-input{display:flex;gap:8px}.calculator-input input{min-width:0;flex:1;padding:12px;border:1px solid var(--ipv4-line);color:var(--ipv4-ink);background:#fff;font:14px Courier New,monospace;outline-color:var(--ipv4-orange)}.calculator-input button{display:inline-flex;align-items:center;gap:7px;padding:0 15px;color:#fff;background:var(--ipv4-orange);border:0;font-size:11px;font-weight:700;cursor:pointer}.calculator-input button:hover{background:#d83d0c}.calculator-error{color:#b42318;font-size:11px}.result-summary{display:grid;grid-template-columns:repeat(3,1fr);gap:1px;margin-top:25px;background:var(--ipv4-line)}.result-summary div{padding:14px;background:#ecece8}.result-summary span{display:block;color:#777770;font:9px Courier New,monospace}.result-summary strong{display:block;margin-top:8px;font-size:22px;letter-spacing:-.05em}.result-table{margin-top:24px;border-top:1px solid var(--ipv4-line)}.result-table div{display:grid;grid-template-columns:110px 1fr 1.3fr;gap:12px;align-items:center;padding:11px 0;border-bottom:1px solid var(--ipv4-line)}.result-table span,.result-table small{color:#777770;font-size:10px}.result-table strong{color:var(--ipv4-orange);font:12px Courier New,monospace}.result-table small{line-height:1.25}.binary-mask{display:flex;justify-content:space-between;gap:12px;margin-top:20px;color:#777770;font-size:10px}.binary-mask code{color:var(--ipv4-ink);font:10px Courier New,monospace}.cidr-table{margin-top:70px;border-top:1px solid var(--ipv4-line)}.cidr-table-head,.cidr-row{display:grid;grid-template-columns:.6fr 1fr .8fr 1.6fr;gap:18px;align-items:center}.cidr-table-head{padding:12px 0;color:#777770;font:9px Courier New,monospace}.cidr-row{min-height:58px;border-top:1px solid var(--ipv4-line)}.cidr-row strong{color:var(--ipv4-orange);font:18px Courier New,monospace}.cidr-row code,.cidr-row span{font:11px Courier New,monospace}.cidr-row p{margin:0;color:#777770;font-size:11px}.vlsm-section{display:grid;grid-template-columns:.8fr 1.5fr;gap:90px;background:#ecece8}.vlsm-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:1px;background:var(--ipv4-line)}.vlsm-grid article{min-height:240px;padding:20px;background:var(--ipv4-paper)}.vlsm-grid article:nth-child(2){background:#e3e3de}.vlsm-grid article:nth-child(3){color:#fff;background:var(--ipv4-orange)}.vlsm-grid article>span{display:block;margin-bottom:48px;color:var(--ipv4-orange);font:9px Courier New,monospace}.vlsm-grid article:nth-child(3)>span{color:#76250f}.vlsm-grid svg{margin-bottom:18px;color:var(--ipv4-orange)}.vlsm-grid article:nth-child(3) svg{color:#fff}.vlsm-grid h3{margin:0 0 7px;font-size:17px;letter-spacing:-.04em}.vlsm-grid p{max-width:190px;margin:0;color:#6b6b64;font-size:11px;line-height:1.4}.vlsm-grid article:nth-child(3) p{color:#76250f}.vlsm-calculator{margin-top:50px;padding:24px;background:var(--ipv4-paper);border:1px solid var(--ipv4-line)}.vlsm-inputs>label{display:block;margin-bottom:8px;color:#777770;font:9px Courier New,monospace;text-transform:uppercase}.vlsm-inputs>input{width:100%;padding:11px;border:1px solid var(--ipv4-line);color:var(--ipv4-ink);background:#fff;font:13px Courier 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13px;border:0;font-size:11px;font-weight:700;cursor:pointer}.vlsm-add{color:var(--ipv4-ink);background:#e5e5e0}.vlsm-run{color:#fff;background:var(--ipv4-orange)}.vlsm-error{margin:14px 0 0;color:#b42318;font-size:11px}.vlsm-results{margin-top:26px;border-top:1px solid var(--ipv4-line)}.vlsm-results-head,.vlsm-result-row{display:grid;grid-template-columns:1.1fr .6fr 1.2fr 1.2fr;gap:14px;align-items:center}.vlsm-results-head{padding:11px 0;color:#777770;font:9px Courier New,monospace}.vlsm-result-row{min-height:66px;border-top:1px solid var(--ipv4-line)}.vlsm-result-row strong{font-size:12px}.vlsm-result-row strong small,.vlsm-result-row span small{display:block;margin-top:4px;color:#777770;font:9px Courier New,monospace}.vlsm-result-row code{color:var(--ipv4-orange);font:14px Courier New,monospace}.vlsm-result-row>span{color:#55554f;font:10px/1.4 Courier New,monospace}.drill-section{display:grid;grid-template-columns:.85fr 1.5fr;gap:80px}.drill-panel{padding:24px;background:#ecece8;border:1px solid var(--ipv4-line)}.drill-top{display:flex;align-items:center;gap:15px;color:#777770;font:9px Courier New,monospace}.drill-top strong{color:var(--ipv4-orange);font-size:12px}.drill-top button{display:inline-flex;align-items:center;gap:6px;margin-left:auto;padding:7px 10px;border:1px solid var(--ipv4-line);color:var(--ipv4-ink);background:transparent;font-size:10px;cursor:pointer}.drill-question{margin:38px 0 24px;font-size:18px;line-height:1.2;letter-spacing:-.03em}.drill-question strong{color:var(--ipv4-orange);font-family:Courier New,monospace}.drill-fields{display:grid;grid-template-columns:1fr 1fr;gap:14px}.drill-fields label{display:flex;flex-direction:column;gap:7px;color:#777770;font:9px Courier New,monospace;text-transform:uppercase}.drill-fields input{padding:10px;border:1px solid var(--ipv4-line);color:var(--ipv4-ink);background:#fff;font:12px Courier New,monospace;outline-color:var(--ipv4-orange)}.drill-check{display:inline-flex;align-items:center;gap:7px;margin-top:22px;padding:11px 14px;color:#fff;background:var(--ipv4-orange);border:0;font-size:11px;font-weight:700;cursor:pointer}.drill-feedback{margin:15px 0 0;color:#b42318;font-size:11px}.drill-feedback.correct{color:#14783c}.ipv4-next{display:flex;align-items:end;justify-content:space-between;padding:110px clamp(28px,6vw,100px) 130px;background:var(--ipv4-orange)}.ipv4-next h2{margin-bottom:0;font-size:clamp(3rem,6vw,6.5rem)}.ipv4-button{display:inline-flex;align-items:center;gap:24px;padding:14px 17px;color:#fff!important;background:var(--ipv4-ink);font-size:11px;font-weight:600}.ipv4-button svg{transition:transform .2s ease}.ipv4-button:hover svg{transform:translate(4px)}@media(max-width:720px){.ipv4-nav{padding:0 18px}.ipv4-nav>span:nth-child(2){display:none}.ipv4-hero{display:block;padding:76px 20px 70px}.ipv4-hero h1{font-size:clamp(3.2rem,15vw,5rem)}.ipv4-hero-illustration{margin-top:45px}.ipv4-hero-illustration img{min-height:220px}.ipv4-section{padding:70px 20px}.address-parts,.calculator-section,.vlsm-section,.bit-section,.drill-section{display:block}.address-parts article{min-height:170px;border-bottom:1px solid var(--ipv4-line)}.address-parts article:last-child{border-bottom:0}.address-parts strong{margin-bottom:35px}.binary-note{display:block}.binary-note code{display:block;margin:14px 0;font-size:11px}.calculator-panel,.bit-panel,.drill-panel{margin-top:35px;padding:17px}.bit-legend strong{width:100%;margin-left:0}.calculator-input{display:block}.calculator-input button{width:100%;justify-content:center;min-height:42px;margin-top:8px}.result-summary{grid-template-columns:1fr}.result-table div{grid-template-columns:1fr 1fr}.result-table small{grid-column:1 / -1}.binary-mask{display:block}.binary-mask code{display:block;margin-top:8px}.cidr-table{overflow-x:auto}.cidr-table-head,.cidr-row{min-width:650px}.vlsm-grid{display:block;margin-top:35px}.vlsm-grid article{min-height:170px;border-bottom:1px solid var(--ipv4-line)}.vlsm-grid article:last-child{border-bottom:0}.vlsm-grid article>span{margin-bottom:25px}.vlsm-calculator{margin-top:35px;padding:17px}.vlsm-requirement{grid-template-columns:1fr 82px 28px}.vlsm-actions{display:grid;grid-template-columns:1fr}.vlsm-add,.vlsm-run{justify-content:center}.vlsm-results{overflow-x:auto}.vlsm-results-head,.vlsm-result-row{min-width:620px}.ipv4-next{display:block;padding:80px 20px 90px}.ipv4-button{margin-top:35px}}.routing-page{--routing-ink: #171717;--routing-paper: #f7f7f4;--routing-line: #d9d9d4;--routing-orange: #ff4b12;min-height:100vh;color:var(--routing-ink);background:var(--routing-paper);font-family:Arial,Helvetica,sans-serif}.routing-page,.routing-page *{box-sizing:border-box}.routing-page a{color:inherit;text-decoration:none}.routing-nav{display:flex;align-items:center;justify-content:space-between;min-height:48px;padding:0 24px;border-bottom:1px solid var(--routing-line);color:#777770;font:9px Courier New,monospace}.routing-back{display:inline-flex;align-items:center;gap:8px;color:var(--routing-ink)!important;font:600 10px Arial,sans-serif}.routing-back:hover{color:var(--routing-orange)!important}.routing-eyebrow{display:block;color:#777770;font:9px/1.2 Courier New,monospace;letter-spacing:.04em}.routing-hero{display:grid;grid-template-columns:minmax(0,1fr) minmax(320px,380px);align-items:center;max-width:1440px;margin:0 auto;padding:100px clamp(28px,5vw,80px) 90px;border-bottom:1px solid var(--routing-line)}.routing-hero h1,.routing-heading h2,.routing-next h2{margin:22px 0 26px;font-size:clamp(3.4rem,7vw,7.2rem);line-height:.88;letter-spacing:-.075em}.routing-hero h1 em,.routing-heading h2 em,.routing-next h2 em{font-style:normal;font-weight:400}.routing-hero p,.routing-heading>p{max-width:400px;color:#63635d;font-size:14px;line-height:1.4}.routing-hero-illustration{margin:0;overflow:hidden;background:transparent}.routing-hero-illustration img{display:block;width:100%;min-height:360px;object-fit:contain}.routing-section{max-width:1440px;margin:0 auto;padding:100px clamp(28px,6vw,100px);border-bottom:1px solid var(--routing-line)}.routing-concept{background:#ecece8}.routing-concept-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:1px;margin-top:70px;background:var(--routing-line)}.routing-concept-grid article{min-height:235px;padding:22px;background:var(--routing-paper)}.routing-concept-grid article:nth-child(2){background:#e2e2dd}.routing-concept-grid article:nth-child(3){color:#fff;background:var(--routing-orange)}.routing-concept-grid article>span{display:block;margin-bottom:50px;color:var(--routing-orange);font:9px Courier New,monospace}.routing-concept-grid article:nth-child(3)>span{color:#76250f}.routing-concept-grid svg{margin-bottom:18px;color:var(--routing-orange)}.routing-concept-grid article:nth-child(3) svg{color:#fff}.routing-concept-grid h3{margin:0 0 8px;font-size:18px;letter-spacing:-.04em}.routing-concept-grid p{max-width:230px;margin:0;color:#6b6b64;font-size:11px;line-height:1.4}.routing-concept-grid article:nth-child(3) p{color:#76250f}.topology-section{display:flex;flex-direction:column;gap:36px;background:#f4f4f0}.topology-section .routing-heading>p{max-width:680px}.lab-topology-container{display:flex;flex-direction:column;border:1px solid var(--routing-line);background:var(--routing-paper);box-shadow:0 4px 20px #00000008}.lab-topo-toolbar{display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:16px;padding:16px 24px;border-bottom:1px solid var(--routing-line);background:#ebebe6}.lab-topo-group{display:flex;align-items:center;gap:12px;flex-wrap:wrap}.lab-topo-label{font:700 9px Courier New,monospace;color:#777770;letter-spacing:.06em}.lab-topo-btn-group{display:inline-flex;border:1px solid var(--routing-line);background:#fff}.lab-topo-btn{padding:7px 14px;border:0;border-right:1px solid var(--routing-line);background:transparent;font:600 11px Arial,sans-serif;color:var(--routing-ink);cursor:pointer;transition:all .15s ease}.lab-topo-btn:last-child{border-right:0}.lab-topo-btn:hover:not(:disabled){background:#f0f0ec}.lab-topo-btn.is-active{background:var(--routing-ink);color:#fff}.lab-topo-btn:disabled{opacity:.5;cursor:not-allowed}.lab-topo-status-badge{display:flex;align-items:center}.badge-route-wrapper{display:inline-flex;align-items:center;gap:10px;flex-wrap:wrap}.badge-route{display:inline-flex;align-items:center;gap:6px;padding:6px 12px;font:700 10px Courier New,monospace;letter-spacing:.02em;border:1px solid transparent}.badge-route.success{background:#e8f5e9;color:#1b5e20;border-color:#a5d6a7}.badge-route.danger{background:#ffebee;color:#c62828;border-color:#ef9a9a}.btn-quick-add-route{display:inline-flex;align-items:center;padding:6px 12px;background:var(--routing-orange);color:#fff;border:0;font:700 10px Arial,sans-serif;cursor:pointer;transition:opacity .15s ease}.btn-quick-add-route:hover{opacity:.88}.lab-topo-canvas{display:flex;flex-direction:column;gap:24px;padding:36px 28px 28px;background:#fafaf8;overflow-x:auto}.lab-topo-flow{display:flex;align-items:center;justify-content:space-between;gap:8px;min-width:860px}.lab-topo-flow.is-direct{min-width:640px;justify-content:flex-start}.topo-link-segment.link-direct{flex:1.2;min-width:110px}.topo-device-card{position:relative;display:flex;flex-direction:column;align-items:center;padding:20px 14px 16px;background:#fff;border:1px solid var(--routing-line);box-shadow:0 2px 8px #00000005;transition:all .25s ease}.device-pc1,.device-server{width:150px;flex-shrink:0}.device-r1,.device-r2{width:200px;flex-shrink:0}.topo-device-card.active-sender{border-color:var(--routing-orange);box-shadow:0 0 0 3px #ff4b122e}.topo-device-card.active-processing{border-color:var(--routing-orange);box-shadow:0 0 0 3px #ff4b1240;animation:pulseDevice 1.2s infinite}.topo-device-card.active-dropped{border-color:#c62828;box-shadow:0 0 0 3px #c6282840}.topo-device-card.active-target{border-color:#2e7d32;box-shadow:0 0 0 3px #2e7d3240}@keyframes pulseDevice{0%,to{transform:translateY(0)}50%{transform:translateY(-2px)}}.device-icon-box{display:flex;align-items:center;justify-content:center;width:48px;height:48px;margin-bottom:10px;background:#f5f5f0;border:1px solid var(--routing-line);color:var(--routing-ink)}.device-icon-box.router-box{background:#eef2ff;border-color:#c7d2fe;color:#3730a3}.device-icon-box.server-box{background:#f0fdf4;border-color:#bbf7d0;color:#166534}.device-name{font-size:13px;font-weight:700;color:var(--routing-ink);margin-bottom:3px}.device-ip{font:11px Courier New,monospace;color:var(--routing-orange);font-weight:600}.device-gw{margin-top:2px;font:9px Courier New,monospace;color:#777770}.device-network-tag{display:inline-block;margin-top:8px;padding:2px 6px;background:#f4f4f0;border:1px solid var(--routing-line);font:8px Courier New,monospace;color:#555550}.device-ports{display:flex;justify-content:space-between;width:100%;margin-top:10px;padding-top:8px;border-top:1px dashed var(--routing-line);font:9px Courier New,monospace;color:#666660}.port-item.left{text-align:left}.port-item.right{text-align:right}.device-routing-status{width:100%;margin-top:8px}.lookup-pill{display:inline-flex;align-items:center;justify-content:center;gap:5px;width:100%;padding:4px 6px;font:700 8px Courier New,monospace;background:#fff8e1;color:#b78103;border:1px solid #ffe082}.lookup-pill.drop{background:#ffebee;color:#c62828;border-color:#ef9a9a}.spin-fast{animation:spin .8s linear infinite}@keyframes spin{0%{transform:rotate(0)}to{transform:rotate(360deg)}}.route-info{display:block;padding:3px 6px;font:700 8px Courier New,monospace;text-align:center}.route-info.active{color:#166534;background:#dcfce7;border:1px solid #86efac}.route-info.inactive{color:#991b1b;background:#fee2e2;border:1px solid #fca5a5}.topo-link-segment{flex:1;min-width:80px;display:flex;flex-direction:column;align-items:center;gap:8px;padding:0 4px}.topo-link-segment.link-wan{flex:1.35;min-width:120px}.cable-line{position:relative;width:100%;height:3px;background:var(--routing-line);transition:background .3s ease}.cable-line.wan-cable{height:5px;background:#d4d4cb;border-top:1px dashed #888880;border-bottom:1px dashed #888880}.cable-line.cable-active{background:var(--routing-orange)}.link-label{font:8px Courier New,monospace;color:#777770;white-space:nowrap;letter-spacing:.02em}.flowing-packet{position:absolute;top:-14px;transform:translate(-50%);display:inline-flex;align-items:center;padding:3px 8px;border-radius:12px;font:700 9px Courier New,monospace;white-space:nowrap;pointer-events:none;z-index:10}.packet-forward{background:var(--routing-orange);color:#fff;animation:packetFlowForward .9s cubic-bezier(.4,0,.2,1) infinite;box-shadow:0 2px 8px #ff4b1266}.packet-reply{background:#15803d;color:#fff;animation:packetFlowReply .9s cubic-bezier(.4,0,.2,1) infinite;box-shadow:0 2px 8px #15803d66}@keyframes packetFlowForward{0%{left:0%;opacity:0}15%{opacity:1}85%{opacity:1}to{left:100%;opacity:0}}@keyframes packetFlowReply{0%{left:100%;opacity:0}15%{opacity:1}85%{opacity:1}to{left:0%;opacity:0}}.lab-packet-inspector{display:flex;flex-direction:column;gap:10px;padding:16px 20px;background:#171717;border:1px solid #333330;color:#fff}.inspector-header{display:flex;align-items:center;gap:8px;padding-bottom:8px;border-bottom:1px solid #292929;color:var(--routing-orange);font:700 10px Courier New,monospace;letter-spacing:.06em}.inspector-grid{display:grid;grid-template-columns:repeat(5,1fr);gap:16px}.insp-item{display:flex;flex-direction:column;gap:4px}.insp-item small{font:700 9px Courier New,monospace;color:#888880;letter-spacing:.04em;text-transform:uppercase}.insp-item code{font:11px Courier New,monospace;color:#38bdf8;word-break:break-all}.lab-cli-output{display:flex;flex-direction:column;border:1px solid #333330;background:#0d0d0d}.cli-bar{display:flex;align-items:center;gap:8px;padding:8px 16px;border-bottom:1px solid #262626;background:#1a1a1a;color:#b2b2aa;font:10px Courier New,monospace}.lab-cli-output pre{margin:0;padding:16px 20px;color:#deded8;font:11px/1.6 Courier New,monospace;white-space:pre-wrap;max-height:200px;overflow-y:auto}.lab-topo-footer{display:flex;align-items:center;justify-content:space-between;gap:20px;padding:18px 24px;border-top:1px solid var(--routing-line);background:#ebebe6;flex-wrap:wrap}.lab-topo-narration{display:flex;align-items:center;gap:12px;flex:1;min-width:280px}.status-dot{width:9px;height:9px;border-radius:50%;flex-shrink:0;background:#888880}.status-dot.active{background:var(--routing-orange);animation:pulseDot 1s infinite alternate}.status-dot.success{background:#16a34a}.status-dot.danger{background:#dc2626}@keyframes pulseDot{0%{transform:scale(.9);opacity:.6}to{transform:scale(1.3);opacity:1}}.lab-topo-narration p{margin:0;font-size:13px;line-height:1.45;color:var(--routing-ink);font-weight:500}.lab-topo-actions{display:flex;align-items:center;gap:10px}.lab-btn-primary{display:inline-flex;align-items:center;gap:8px;padding:11px 20px;border:0;background:var(--routing-orange);color:#fff;font:700 11px Arial,sans-serif;cursor:pointer;transition:all .15s ease}.lab-btn-primary:hover{background:#e03e09}.lab-btn-secondary{display:inline-flex;align-items:center;gap:8px;padding:11px 20px;border:0;background:#242422;color:#fff;font:700 11px Arial,sans-serif;cursor:pointer;transition:all .15s ease}.lab-btn-secondary:hover{background:#3b3b38}.interface-section{display:grid;grid-template-columns:.85fr 1.5fr;gap:80px;background:#ecece8}.interface-panel{padding:24px;background:var(--routing-paper);border:1px solid var(--routing-line)}.interface-form{display:grid;grid-template-columns:1fr 1fr;gap:12px}.interface-form label{display:flex;flex-direction:column;gap:7px;color:#777770;font:9px Courier New,monospace;text-transform:uppercase}.interface-form input{min-width:0;padding:10px;border:1px solid var(--routing-line);color:var(--routing-ink);background:#fff;font:12px Courier New,monospace;outline-color:var(--routing-orange)}.interface-form label:nth-child(3){grid-column:1 / 2}.interface-form button{align-self:end;display:inline-flex;align-items:center;justify-content:center;gap:7px;min-height:37px;padding:0 13px;color:#fff;background:var(--routing-orange);border:0;font-size:10px;font-weight:700;cursor:pointer}.interface-list{margin-top:28px;border-top:1px solid var(--routing-line)}.interface-row{display:grid;grid-template-columns:10px 1.1fr 1.1fr 1fr .7fr;gap:12px;align-items:center;min-height:56px;border-bottom:1px solid var(--routing-line);font-size:10px}.interface-row code{color:var(--routing-orange);font:10px Courier New,monospace}.interface-row>span:not(.interface-status){color:#777770}.interface-row small{color:#14783c;font:9px Courier New,monospace}.interface-status{width:7px;height:7px;border-radius:50%;background:#14783c}.interface-status.disabled{background:#b42318}.interface-toggle{justify-self:start;padding:5px 7px;color:#14783c;background:transparent;border:1px solid var(--routing-line);font:8px Courier New,monospace;cursor:pointer}.interface-toggle:hover{color:#fff;background:var(--routing-orange);border-color:var(--routing-orange)}.route-table-section{display:grid;grid-template-columns:.85fr 1.5fr;gap:80px;background:#ecece8}.route-panel{padding:24px;background:var(--routing-paper);border:1px solid var(--routing-line)}.route-form{display:grid;grid-template-columns:1fr 1fr 100px auto;gap:10px;align-items:end}.route-form label{display:flex;flex-direction:column;gap:7px;color:#777770;font:9px Courier New,monospace;text-transform:uppercase}.route-form input{min-width:0;padding:10px;border:1px solid var(--routing-line);color:var(--routing-ink);background:#fff;font:12px Courier New,monospace;outline-color:var(--routing-orange)}.route-form button{display:inline-flex;align-items:center;gap:7px;height:37px;padding:0 13px;color:#fff;background:var(--routing-orange);border:0;font-size:10px;font-weight:700;cursor:pointer}.route-table{margin-top:28px;border-top:1px solid var(--routing-line)}.route-table-head,.route-row{display:grid;grid-template-columns:1.3fr 1.1fr 1.1fr .8fr;gap:12px;align-items:center}.route-table-head{padding:10px 0;color:#777770;font:9px Courier New,monospace}.route-row{min-height:50px;border-top:1px solid var(--routing-line);color:#65655e;font-size:10px}.route-row code{color:var(--routing-orange);font:10px Courier New,monospace}.route-success{display:flex;align-items:center;gap:7px;margin:20px 0 0;color:#14783c;font-size:11px}.lookup-section{display:grid;grid-template-columns:.85fr 1.5fr;gap:80px}.lookup-panel{align-self:center;padding:24px;background:#ecece8;border:1px solid var(--routing-line)}.lookup-panel>label{display:block;margin-bottom:8px;color:#777770;font:9px Courier New,monospace;text-transform:uppercase}.lookup-input{display:flex;align-items:center;gap:12px}.lookup-input input{width:180px;padding:11px;border:1px solid var(--routing-line);color:var(--routing-ink);background:#fff;font:12px Courier New,monospace;outline-color:var(--routing-orange)}.lookup-input>span{color:var(--routing-orange);font-size:18px}.lookup-input strong{color:var(--routing-orange);font:12px Courier New,monospace}.lookup-result,.lookup-error{display:flex;align-items:flex-start;gap:8px;margin:24px 0 0;padding-top:18px;border-top:1px solid var(--routing-line);color:#14783c;font-size:12px;line-height:1.35}.lookup-result p{margin:0}.lookup-result svg{flex:0 0 auto}.lookup-error{color:#b42318}.terminal-section{background:#171717;color:#fff}.terminal-section .routing-eyebrow{color:#96968e}.terminal-section .routing-heading h2{color:#fff}.terminal-panel{max-width:760px;margin-top:65px;border:1px solid #3b3b38;background:#0d0d0d}.terminal-title{display:flex;align-items:center;gap:8px;padding:12px 15px;border-bottom:1px solid #3b3b38;color:#b2b2aa;font:10px Courier New,monospace}.terminal-title svg{color:var(--routing-orange)}.terminal-title span{margin-left:auto;color:#76250f}.terminal-panel pre{min-height:250px;max-height:350px;overflow:auto;margin:0;padding:18px;color:#deded8;font:11px/1.55 Courier New,monospace;white-space:pre-wrap}.terminal-input{display:flex;gap:9px;padding:12px 15px;border-top:1px solid #3b3b38;color:var(--routing-orange);font:12px Courier New,monospace}.terminal-input input{flex:1;min-width:0;color:#fff;background:transparent;border:0;outline:0;font:inherit}.terminal-input input::placeholder{color:#66665f}.command-chips{display:flex;flex-wrap:wrap;gap:8px;max-width:760px;margin-top:15px}.command-chips button{padding:7px 10px;color:#b2b2aa;background:#242422;border:1px solid #3b3b38;font:10px Courier New,monospace;cursor:pointer}.command-chips button:hover{color:#fff;border-color:var(--routing-orange)}.diagnostic-section{display:grid;grid-template-columns:.85fr 1.5fr;gap:80px;background:#ecece8}.diagnostic-panel{padding:24px;background:var(--routing-paper);border:1px solid var(--routing-line)}.diagnostic-steps{display:grid;grid-template-columns:repeat(3,1fr);gap:1px;background:var(--routing-line)}.diagnostic-steps button{display:flex;flex-direction:column;align-items:flex-start;min-height:150px;padding:17px;border:0;text-align:left;background:var(--routing-paper);cursor:pointer}.diagnostic-steps button:nth-child(2){background:#e3e3de}.diagnostic-steps button:nth-child(3){color:#fff;background:var(--routing-orange)}.diagnostic-steps button:hover{outline:2px solid var(--routing-orange);outline-offset:-2px}.diagnostic-steps span{margin-bottom:auto;color:var(--routing-orange);font:9px Courier New,monospace}.diagnostic-steps button:nth-child(3) span{color:#76250f}.diagnostic-steps strong{font-size:14px}.diagnostic-steps small{margin-top:7px;color:#777770;font:9px Courier New,monospace}.diagnostic-steps button:nth-child(3) small{color:#76250f}.diagnostic-output{display:flex;align-items:flex-start;gap:8px;margin-top:20px;padding:14px;color:#14783c;background:#e6f4eb;font-size:11px;line-height:1.35}.diagnostic-output.is-error{color:#b42318;background:#fcebea}.routing-next{display:flex;align-items:end;justify-content:space-between;padding:110px clamp(28px,6vw,100px) 130px;background:var(--routing-orange)}.routing-next h2{margin-bottom:0;font-size:clamp(3rem,6vw,6.5rem)}.routing-button{display:inline-flex;align-items:center;gap:24px;padding:14px 17px;color:#fff!important;background:var(--routing-ink);font-size:11px;font-weight:600}.routing-button svg{transition:transform .2s ease}.routing-button:hover svg{transform:translate(4px)}@media(prefers-reduced-motion:reduce){.routing-link.is-running i{animation:none}}@media(max-width:720px){.routing-nav{padding:0 18px}.routing-nav>span:nth-child(2){display:none}.routing-hero{display:block;padding:76px 20px 70px}.routing-hero h1{font-size:clamp(3.2rem,15vw,5rem)}.routing-hero-illustration{margin-top:45px}.routing-hero-illustration img{min-height:240px}.routing-section{padding:70px 20px}.routing-concept-grid,.interface-section,.route-table-section,.lookup-section,.diagnostic-section{display:block}.topology-section{display:flex;flex-direction:column;gap:24px}.lab-topo-toolbar{padding:14px 16px}.lab-topo-btn-group{width:100%;overflow-x:auto}.lab-topo-btn{flex:1;text-align:center;padding:7px 8px;font-size:10px;white-space:nowrap}.lab-topo-canvas{padding:20px 14px}.inspector-grid{grid-template-columns:repeat(2,1fr)}.lab-topo-footer{padding:14px 16px;flex-direction:column;align-items:stretch}.lab-topo-actions{width:100%}.lab-btn-primary,.lab-btn-secondary{width:100%;justify-content:center}.routing-concept-grid article{min-height:180px;border-bottom:1px solid var(--routing-line)}.routing-concept-grid article:last-child{border-bottom:0}.routing-concept-grid article>span{margin-bottom:30px}.interface-panel{margin-top:35px;padding:17px}.interface-form{grid-template-columns:1fr}.interface-form label:nth-child(3){grid-column:auto}.interface-form button{margin-top:3px}.interface-list{overflow-x:auto}.interface-row{min-width:620px}.route-panel{margin-top:35px;padding:17px}.route-form{grid-template-columns:1fr}.route-form button{justify-content:center}.route-table{overflow-x:auto}.route-table-head,.route-row{min-width:570px}.lookup-panel,.diagnostic-panel{margin-top:35px;padding:17px}.lookup-input{flex-wrap:wrap}.lookup-input input,.lookup-input strong{width:100%}.terminal-panel{margin-top:35px}.diagnostic-steps{display:block}.diagnostic-steps button{min-height:120px;border-bottom:1px solid var(--routing-line)}.diagnostic-steps button:last-child{border-bottom:0}.routing-next{display:block;padding:80px 20px 90px}.routing-button{margin-top:35px}}.vlan-page{--vlan-ink: #191a18;--vlan-paper: #f5f5f0;--vlan-muted: #70726b;--vlan-line: #d8d9d1;--vlan-orange: #ff4b12;min-height:100vh;color:var(--vlan-ink);background:var(--vlan-paper);font-family:Arial,Helvetica,sans-serif}.vlan-page,.vlan-page *{box-sizing:border-box}.vlan-page button,.vlan-page input,.vlan-page select{font:inherit}.vlan-page button{cursor:pointer}.vlan-page a{color:inherit;text-decoration:none}.vlan-nav{display:flex;align-items:center;justify-content:space-between;min-height:48px;padding:0 25px;border-bottom:1px solid var(--vlan-line);color:var(--vlan-muted);font:9px Courier New,monospace}.vlan-back{display:inline-flex;align-items:center;gap:8px;color:var(--vlan-ink)!important;font:600 10px Arial,sans-serif}.vlan-back:hover{color:var(--vlan-orange)!important}.vlan-nav-links{display:inline-flex;align-items:center;gap:16px}.vlan-nav-links a{color:var(--vlan-muted);font:9px Courier New,monospace;text-decoration:underline;text-underline-offset:3px}.vlan-nav-links a:hover{color:var(--vlan-orange)}.vlan-kicker{color:var(--vlan-muted);font:9px/1.3 Courier New,monospace;letter-spacing:.08em}.vlan-intro{display:grid;grid-template-columns:minmax(0,1fr) minmax(370px,500px);gap:80px;align-items:center;max-width:1440px;margin:auto;padding:108px clamp(28px,7vw,112px) 96px;border-bottom:1px solid var(--vlan-line)}.vlan-intro h1,.vlan-section-title h2,.quiz-section h2,.vlan-next h2{margin:22px 0 26px;font-size:clamp(3.1rem,6.5vw,7rem);line-height:.88;letter-spacing:-.08em}.vlan-intro h1 em,.vlan-section-title h2 em,.quiz-section h2 em,.vlan-next h2 em{font-style:normal;font-weight:400}.vlan-intro p,.vlan-section-title>p{max-width:450px;color:#62645e;font-size:14px;line-height:1.45}.segment-map{padding:19px;border:1px solid var(--vlan-line);background:#e9e9e3}.segment-map-title{margin-bottom:10px;color:var(--vlan-muted);font:9px Courier New,monospace;display:flex;justify-content:space-between;align-items:center}.segment-row{display:grid;grid-template-columns:83px 1.1fr 1.6fr;gap:10px;align-items:center;min-height:54px;padding:0 13px;border-bottom:1px solid rgba(0,0,0,.08);position:relative}.segment-row:last-child{border-bottom:0}.segment-row strong,.segment-row span{font:700 11px Courier New,monospace}.segment-row small{color:#6d6e67;font-size:10px}.segment-row small code{display:block;font-family:Courier New,monospace;font-size:9px;color:inherit;opacity:.85}.segment-row.green{color:#216942;background:#dcebdd}.segment-row.blue{color:#244f76;background:#dce5ef}.segment-row.purple{color:#624676;background:#e8dfef}.segment-row.orange{color:#864125;background:#f5dfd3}.segment-row.teal{color:#1e5a59;background:#d8eceb}.vlan-section{max-width:1440px;margin:auto;padding:105px clamp(28px,7vw,112px);border-bottom:1px solid var(--vlan-line)}.vlan-principles{display:grid;grid-template-columns:.75fr 1.5fr;gap:75px;background:#e9e9e3}.principle-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:1px;align-self:end;background:var(--vlan-line)}.principle-grid article{min-height:245px;padding:20px;background:var(--vlan-paper)}.principle-grid article:nth-child(2){background:#e0e1db}.principle-grid article:nth-child(3){color:#fff;background:var(--vlan-orange)}.principle-grid svg{width:23px;height:23px;margin:50px 0 17px;color:var(--vlan-orange);stroke-width:1.3}.principle-grid article:nth-child(3) svg{color:#fff}.principle-grid span{display:block;color:var(--vlan-muted);font:9px Courier New,monospace}.principle-grid article:nth-child(3) span{color:#76250f}.principle-grid h3{margin:0 0 8px;font-size:17px}.principle-grid p{max-width:210px;margin:0;color:#6c6e67;font-size:11px;line-height:1.4}.principle-grid article:nth-child(3) p{color:#76250f}.tag-section{display:grid;grid-template-columns:.75fr 1.5fr;gap:75px}.frame-inspector{padding:22px;background:#e9e9e3;border:1px solid var(--vlan-line)}.frame-selector{display:flex;flex-wrap:wrap;gap:6px;margin-bottom:25px}.frame-selector button{padding:10px 13px;color:var(--vlan-muted);background:transparent;border:1px solid var(--vlan-line);font:11px Courier New,monospace;transition:all .15s ease}.frame-selector button small{display:block;margin-top:4px;font-size:8px}.frame-selector button.is-selected{color:#fff;background:var(--vlan-ink);border-color:var(--vlan-ink)}.frame-visual-wrap{overflow-x:auto;margin-bottom:20px;border:1px solid var(--vlan-line);background:#fff}.frame-visual{display:grid;grid-template-columns:1fr 1fr 1fr 1.5fr 1fr 1.2fr .6fr;min-width:600px;min-height:90px}.frame-visual>*{display:flex;flex-direction:column;align-items:center;justify-content:center;padding:10px 6px;border-right:1px solid var(--vlan-line);text-align:center;font:9px Courier New,monospace;gap:3px}.frame-visual>*:last-child{border-right:0}.frame-visual>b{color:var(--vlan-orange);background:#fff0e9}.frame-visual strong{font-size:10px}.frame-visual span{color:var(--vlan-muted)}.frame-notes{display:grid;grid-template-columns:repeat(4,1fr);gap:15px;margin-top:20px}.frame-notes div{display:flex;flex-direction:column;gap:7px}.frame-notes strong{font:10px Courier New,monospace}.frame-notes span{color:var(--vlan-muted);font-size:10px;line-height:1.35}.frame-detail-box{margin-top:18px;padding:12px 16px;background:#fbfbf9;border:1px solid var(--vlan-line);font:10px Courier New,monospace;color:var(--vlan-ink);line-height:1.6}.frame-detail-box span.accent{color:var(--vlan-orange);font-weight:700}.lab-section{background:#ecece7}.lab-section .vlan-section-title{max-width:600px}.vlan-lab{margin-top:58px}.vlan-topology-stage{border:1px solid var(--vlan-line);background:#fbfbf9;margin-bottom:24px;overflow:hidden}.topo-narration-bar{padding:16px 20px;background:var(--vlan-ink);color:#fff;border-bottom:1px solid #333}.topo-step-indicator{display:flex;align-items:center;gap:10px;margin-bottom:6px}.step-badge{padding:3px 8px;background:var(--vlan-orange);color:#fff;font:700 9px Courier New,monospace;letter-spacing:.05em;border-radius:2px}.step-badge.is-success{background:#216942}.step-badge.is-drop{background:#c93b1b}.step-title{font:700 12px Courier New,monospace;color:#e5e7e0}.step-narrative{margin:0;font-size:12px;line-height:1.45;color:#b5b8ad}.topo-visual-canvas{padding:24px 20px 20px;position:relative;background:#f4f4ee;overflow-x:auto}.topo-canvas-inner{min-width:760px;display:flex;flex-direction:column;gap:14px}.topo-router-row{display:flex;justify-content:center}.topo-router-device{width:360px;padding:12px 16px;background:var(--vlan-ink);color:#fff;border:1px solid #3d4039;box-shadow:0 4px 12px #00000014;position:relative;transition:all .25s ease}.topo-router-device.is-active{border-color:var(--vlan-orange);box-shadow:0 0 16px #ff4b1266}.topo-router-device.is-dropped{border-color:#c93b1b;box-shadow:0 0 16px #c93b1b80}.topo-device-header{display:flex;align-items:center;gap:10px;margin-bottom:8px}.topo-device-header small{display:block;font-size:9px;color:#9da095}.topo-router-device svg{color:var(--vlan-orange)}.topo-subif-chips{display:flex;flex-wrap:wrap;gap:5px}.subif-chip{padding:2px 7px;font:9px Courier New,monospace;border-radius:2px}.subif-chip.is-up{background:#235c38;color:#c9efd3}.subif-chip.is-down{background:#472620;color:#f7a694;opacity:.7}.subif-chip.is-pulsing{animation:pulse-border .6s infinite alternate;box-shadow:0 0 8px #ff4b12}.topo-vertical-cable-wrap{display:flex;flex-direction:column;align-items:center;position:relative;height:46px;justify-content:center}.topo-v-cable{width:4px;height:100%;background:#c5c7be;position:relative;transition:background .25s ease}.topo-v-cable.is-cable-active{background:var(--vlan-orange);box-shadow:0 0 10px #ff4b1299}.cable-tag{position:absolute;right:calc(50% + 12px);font:9px Courier New,monospace;color:var(--vlan-muted);white-space:nowrap}.topo-switch-row{display:grid;grid-template-columns:240px 1fr 240px;gap:16px;align-items:center}.topo-switch-device{padding:14px;background:var(--vlan-paper);border:1px solid var(--vlan-line);box-shadow:0 2px 8px #0000000a;position:relative;transition:all .25s ease}.topo-switch-device.is-active{border-color:var(--vlan-orange);box-shadow:0 0 14px #ff4b124d}.topo-switch-device.is-dropped{border-color:#c93b1b;box-shadow:0 0 14px #c93b1b66}.topo-switch-device .topo-device-header strong{font-size:13px}.topo-switch-device .topo-device-header svg{color:var(--vlan-orange)}.topo-port-indicators{display:flex;flex-direction:column;gap:4px;margin-top:10px}.port-indicator{display:flex;justify-content:space-between;align-items:center;padding:4px 8px;background:#ebebe5;border:1px solid var(--vlan-line);font:9px Courier New,monospace;color:var(--vlan-ink);transition:all .2s ease}.port-indicator.trunk-ind{background:#e6ddd5}.port-indicator.is-traffic{background:var(--vlan-orange);color:#fff;border-color:var(--vlan-orange)}.topo-trunk-link-container{display:flex;flex-direction:column;align-items:center;padding:10px 14px;background:#eaeae4;border:1px dashed #cbccbe;position:relative}.trunk-line-header{display:flex;align-items:center;gap:8px;margin-bottom:8px;font:9px Courier New,monospace}.trunk-badge{padding:2px 7px;background:var(--vlan-ink);color:#fff;border-radius:2px}.topo-trunk-cable{width:100%;height:6px;background:#c3c5bc;position:relative;margin:6px 0;transition:background .25s ease}.topo-trunk-cable.is-cable-active{background:var(--vlan-orange);box-shadow:0 0 10px #ff4b1299}.trunk-meta-footer{display:flex;justify-content:space-between;width:100%;font:8px Courier New,monospace;color:var(--vlan-muted);margin-top:4px}.topo-endpoints-grid{display:grid;grid-template-columns:1fr 1fr;gap:40px;margin-top:10px}.endpoint-group{display:grid;grid-template-columns:1fr 1fr;gap:12px}.topo-endpoint-card{padding:12px;background:var(--vlan-paper);border:1px solid var(--vlan-line);position:relative;transition:all .25s ease}.topo-endpoint-card.is-src{border-color:var(--vlan-orange);background:#fff8f5}.topo-endpoint-card.is-dst{border-color:#216942;background:#f2f8f4}.topo-endpoint-card.is-active{box-shadow:0 0 12px #ff4b1259}.topo-endpoint-card.is-delivered{border-color:#216942;box-shadow:0 0 15px #21694280;background:#dceede}.ep-badge{display:inline-block;padding:1px 6px;background:var(--vlan-ink);color:#fff;font:700 8px Courier New,monospace;margin-bottom:6px;border-radius:2px}.topo-endpoint-card strong{display:block;font-size:12px;margin-bottom:2px}.topo-endpoint-card span{display:block;font:9px Courier New,monospace;color:var(--vlan-muted)}.topo-endpoint-card small{display:block;font-size:9px;color:#888;margin-top:4px}.topo-packet-pill{position:absolute;top:50%;left:50%;transform:translate(-50%,-50%);display:inline-flex;align-items:center;gap:6px;padding:5px 12px;background:var(--vlan-orange);color:#fff;border-radius:14px;font:700 9px Courier New,monospace;white-space:nowrap;box-shadow:0 3px 10px #ff4b1280;z-index:30;animation:pulse-packet .7s infinite alternate}.topo-packet-pill.is-untagged{background:#333630;box-shadow:0 3px 10px #0000004d}.topo-packet-pill.is-tagged{background:var(--vlan-orange)}.topo-packet-pill.is-routing{background:#624676;box-shadow:0 3px 10px #62467666}.topo-packet-pill.is-success{background:#216942;box-shadow:0 3px 10px #21694266}.topo-packet-pill.is-dropped{background:#c93b1b;box-shadow:0 3px 10px #c93b1b80}@keyframes pulse-packet{0%{transform:translate(-50%,-50%) scale(.96)}to{transform:translate(-50%,-50%) scale(1.04)}}@keyframes pulse-border{0%{opacity:.7}to{opacity:1}}.topo-control-bar{display:flex;justify-content:space-between;align-items:center;flex-wrap:wrap;gap:16px;padding:14px 20px;background:#e9e9e3;border-top:1px solid var(--vlan-line)}.topo-control-source-dest{display:flex;align-items:center;gap:12px;font:9px Courier New,monospace}.topo-control-source-dest label{display:flex;align-items:center;gap:6px;color:var(--vlan-ink)}.topo-control-source-dest select{padding:6px 10px;border:1px solid var(--vlan-line);background:#fff;font-size:11px}.topo-btn-actions{display:flex;align-items:center;gap:8px}.btn-start-anim{display:inline-flex;align-items:center;gap:6px;padding:9px 16px;background:var(--vlan-orange);color:#fff;border:0;font:700 10px Courier New,monospace;cursor:pointer;transition:opacity .15s ease}.btn-start-anim:hover:not(:disabled){opacity:.9}.btn-start-anim:disabled{opacity:.5;cursor:not-allowed}.btn-reset-anim{display:inline-flex;align-items:center;gap:5px;padding:9px 14px;background:var(--vlan-paper);border:1px solid var(--vlan-line);color:var(--vlan-ink);font:10px Courier New,monospace;cursor:pointer}.port-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:1px;background:var(--vlan-line)}.port-card{min-height:178px;padding:16px;background:var(--vlan-paper)}.port-card.trunk{background:#e6ddd5}.port-card-head{display:flex;justify-content:space-between;align-items:baseline;margin-bottom:12px}.port-card-head strong{font:11px Courier New,monospace}.port-card-head span{color:var(--vlan-orange);font:9px Courier New,monospace;text-transform:uppercase}.port-target-hint{color:#63655e;font:9px Courier New,monospace;margin-bottom:8px;display:block}.port-card label{display:flex;flex-direction:column;gap:5px;margin-top:9px;color:var(--vlan-muted);font:9px Courier New,monospace}.port-card select,.packet-test select{padding:7px;border:1px solid var(--vlan-line);background:#fff;color:var(--vlan-ink);font-size:11px}.allowed-vlans{margin-top:10px;color:var(--vlan-muted);font:9px Courier New,monospace}.allowed-vlans div{display:flex;flex-wrap:wrap;gap:5px;margin-top:6px}.allowed-vlans button{padding:5px 7px;border:1px solid var(--vlan-line);color:var(--vlan-muted);background:transparent;font:10px Courier New,monospace;transition:all .15s ease}.allowed-vlans button.allowed{color:#fff;background:var(--vlan-orange);border-color:var(--vlan-orange)}.vlan-create{display:flex;align-items:center;gap:8px;padding:12px 18px;background:#dfe0d9;color:var(--vlan-muted);font:9px Courier New,monospace}.vlan-create input{width:90px;padding:7px;border:1px solid #c5c6be;background:#fff;font:10px Courier New,monospace}.vlan-create input:nth-of-type(2){width:150px}.vlan-create button,.send-frame{padding:7px 11px;color:#fff;background:var(--vlan-orange);border:0;font:9px Courier New,monospace;transition:opacity .15s ease}.vlan-create button:hover,.send-frame:hover{opacity:.9}.vlan-create-msg{color:#a43a1b;margin-left:8px;font-size:9px}.gateway-controls{display:flex;flex-wrap:wrap;align-items:center;gap:7px;padding:13px 18px;background:#dbdcd5;color:var(--vlan-muted);font:9px Courier New,monospace}.gateway-controls button{padding:6px 9px;border:1px solid #c1c2ba;color:#70726b;background:transparent;font:9px Courier New,monospace;transition:all .15s ease}.gateway-controls button.is-on{color:#fff;background:var(--vlan-orange);border-color:var(--vlan-orange)}.gateway-quick-btn{margin-left:auto;padding:4px 8px;background:transparent;border:1px dashed #a5a79f;color:var(--vlan-ink);font:9px Courier New,monospace}.terminal-layout{display:grid;grid-template-columns:.75fr 1.5fr;gap:75px}.terminal-intro-desc{color:#63655e;font-size:13px;line-height:1.5}.terminal-sim-explain{margin-top:24px;padding:16px;background:#e9e9e3;border:1px solid var(--vlan-line);font:10px/1.6 Courier New,monospace;color:var(--vlan-ink)}.terminal-sim-explain strong{display:block;color:var(--vlan-orange);margin-bottom:6px;font-size:10px}.config-console{overflow:hidden;background:#20211f;color:#d4d6ce;border:1px solid #3b3d39;box-shadow:0 4px 16px #00000026}.platform-tabs{display:flex;align-items:center;flex-wrap:wrap;border-bottom:1px solid #3b3d39;background:#191a18}.platform-tabs button{padding:12px 18px;color:#92958d;background:transparent;border:0;font:10px Courier New,monospace;transition:all .15s ease}.platform-tabs button.active{color:#fff;background:var(--vlan-orange)}.terminal-port-selector{display:inline-flex;align-items:center;gap:8px;margin-left:auto;padding:6px 14px;color:#92958d;font:9px Courier New,monospace}.terminal-port-selector select{padding:5px 8px;color:#fff;background:#30322e;border:1px solid #494b45;font:9px Courier New,monospace}.terminal-verification-bar{display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:8px;padding:10px 16px;background:#161715;border-bottom:1px solid #333630;font:9px Courier New,monospace}.verify-item{display:inline-flex;align-items:center;gap:6px;color:#a2a69c}.verify-badge{padding:2px 7px;background:#292b26;color:#e5e7df;border:1px solid #41443c;border-radius:2px}.verify-badge.orange{background:#ff4b1240;color:#ff916d;border-color:#ff4b1280}.verify-badge.green{background:#2169424d;color:#9de5b7;border-color:#21694280}.verify-sync-pill{padding:2px 6px;background:#216942;color:#fff;font-size:8px;border-radius:2px}.config-console pre{display:block;min-height:180px;max-height:280px;overflow-y:auto;margin:0;padding:18px;white-space:pre-wrap;word-break:break-word;color:#c4c8bd;font:11px/1.65 Courier New,monospace}.config-console pre::-webkit-scrollbar{width:6px}.config-console pre::-webkit-scrollbar-thumb{background:#444740}.config-form-row{display:flex;align-items:center;gap:10px;padding:10px 16px;border-top:1px solid #3b3d39;background:#252723}.config-console form{display:flex;align-items:center;gap:10px;flex:1;color:var(--vlan-orange);font:11px Courier New,monospace}.config-console form input{width:100%;color:#fff;background:transparent;border:0;outline:0;font:11px Courier New,monospace}.terminal-run-btn{display:inline-flex;align-items:center;gap:6px;padding:7px 14px;background:var(--vlan-orange);color:#fff;border:0;font:700 9px Courier New,monospace;cursor:pointer;transition:opacity .15s ease}.terminal-run-btn:hover{opacity:.9}.terminal-command-palette{display:flex;flex-direction:column;gap:12px;padding:14px 18px 18px;background:#1e201d;border-top:1px solid #333630}.cmd-palette-group{display:flex;flex-direction:column;gap:6px}.cmd-palette-label{color:#81847a;font:700 9px Courier New,monospace;letter-spacing:.08em;display:flex;align-items:center;gap:6px}.cmd-palette-chips{display:flex;flex-wrap:wrap;gap:6px}.cmd-chip-action{display:inline-flex;align-items:center;gap:6px;padding:6px 10px;color:#cfd2c8;background:#2a2c28;border:1px solid #3d4037;font:9px Courier New,monospace;cursor:pointer;transition:all .15s ease}.cmd-chip-action:hover{background:#363932;border-color:var(--vlan-orange);color:#fff}.cmd-chip-action .chip-tag{font-size:8px;padding:1px 4px;border-radius:2px;background:#ff4b1233;color:#ff9473}.cmd-chip-action .chip-tag.verify{background:#2169424d;color:#92e0b1}.terminal-practice-missions{margin-top:24px;display:grid;grid-template-columns:repeat(2,1fr);gap:1px;background:var(--vlan-line)}.practice-mission-card{padding:18px;background:var(--vlan-paper);display:flex;flex-direction:column;justify-content:space-between;gap:10px}.mission-head{display:flex;justify-content:space-between;align-items:baseline;font:9px Courier New,monospace;color:var(--vlan-muted)}.practice-mission-card strong{font-size:13px;color:var(--vlan-ink)}.practice-mission-card p{margin:0;font-size:11px;color:#63655e;line-height:1.45}.practice-mission-card code{display:block;padding:4px 8px;background:#eaeae4;font:10px Courier New,monospace;color:var(--vlan-ink);margin-top:4px}.mission-action-btn{display:inline-flex;align-items:center;gap:6px;padding:7px 12px;background:var(--vlan-ink);color:#fff;border:0;font:700 9px Courier New,monospace;cursor:pointer;align-self:flex-start;margin-top:4px;transition:background .15s ease}.mission-action-btn:hover{background:var(--vlan-orange)}.diagnose-section{display:grid;grid-template-columns:.75fr 1.5fr;gap:75px;background:#e9e9e3}.diagnose-cases{display:grid;grid-template-columns:repeat(2,1fr);gap:1px;background:var(--vlan-line)}.diagnose-cases button{display:flex;align-items:center;gap:9px;min-height:80px;padding:13px;border:0;color:var(--vlan-ink);background:var(--vlan-paper);text-align:left;font-size:11px;transition:all .15s ease}.diagnose-cases button:hover{color:#fff;background:var(--vlan-orange)}.diagnose-cases button.is-active{background:var(--vlan-ink);color:#fff}.diagnose-cases button.is-active span{color:var(--vlan-orange)}.diagnose-cases span{margin-right:auto;color:var(--vlan-orange);font:9px Courier New,monospace}.diagnose-cases button:hover span{color:#76250f}.diagnostic-output{display:flex;gap:12px;margin-top:18px;padding:16px;font-size:12px;line-height:1.45;align-items:flex-start}.diagnostic-output.is-success{color:#1c6138;background:#dceede;border:1px solid #c2e2c7}.diagnostic-output.is-issue{color:#833118;background:#faeade;border:1px solid #f2c7b5}.diagnostic-output p{margin:0;flex:1}.diagnostic-quickfix{margin-top:10px;display:inline-flex;align-items:center;gap:6px;padding:6px 12px;background:var(--vlan-ink);color:#fff;border:0;font:9px Courier New,monospace;cursor:pointer;transition:opacity .15s ease}.diagnostic-quickfix:hover{opacity:.9}.security-note{display:flex;gap:11px;margin-top:18px;padding:16px;color:#7b391e;background:#f5ddd1;font-size:11px;line-height:1.4}.security-note p{margin:0}.security-note svg{flex:0 0 auto}.quiz-section{display:grid;grid-template-columns:.75fr 1.5fr;gap:75px}.quiz-card{padding:27px;background:#e6e6df;border:1px solid var(--vlan-line)}.quiz-top-bar{display:flex;justify-content:space-between;align-items:center;margin-bottom:16px;padding-bottom:10px;border-bottom:1px solid var(--vlan-line);font:9px Courier New,monospace;color:var(--vlan-muted)}.quiz-score-indicator{padding:3px 8px;background:#d4d6cd;color:var(--vlan-ink);font-weight:700}.quiz-question-text{margin:0 0 20px;font-size:15px;line-height:1.4;color:var(--vlan-ink);font-weight:500}.quiz-options-list{display:flex;flex-direction:column;gap:8px;margin-bottom:20px}.quiz-option-button{display:flex;align-items:center;gap:10px;padding:12px 15px;background:var(--vlan-paper);border:1px solid var(--vlan-line);color:var(--vlan-ink);font-size:11px;text-align:left;line-height:1.4;transition:all .15s ease}.quiz-option-button:hover{border-color:var(--vlan-ink)}.quiz-option-button.selected{background:var(--vlan-ink);color:#fff;border-color:var(--vlan-ink)}.quiz-option-button span.key{font:700 10px Courier New,monospace;opacity:.7}.quiz-actions-row{display:flex;align-items:center;gap:8px;flex-wrap:wrap}.quiz-actions-row button{padding:9px 14px;border:1px solid var(--vlan-line);color:var(--vlan-ink);background:var(--vlan-paper);font-size:11px;transition:all .15s ease}.quiz-actions-row button.btn-primary{color:#fff;background:var(--vlan-orange);border-color:var(--vlan-orange)}.quiz-actions-row button.btn-secondary{color:var(--vlan-ink);background:#d8dad2}.quiz-feedback-box{margin-top:18px;padding:14px;border:1px solid var(--vlan-line);font-size:11px;line-height:1.45}.quiz-feedback-box.is-correct{background:#dceede;color:#1c6138;border-color:#c2e2c7}.quiz-feedback-box.is-wrong{background:#faeade;color:#833118;border-color:#f2c7b5}.quiz-feedback-box strong{display:block;margin-bottom:4px;font:11px Courier New,monospace}.quiz-feedback-box p{margin:0}.vlan-next{display:flex;align-items:end;justify-content:space-between;padding:100px clamp(28px,7vw,112px) 120px;color:#fff;background:var(--vlan-orange)}.vlan-next .vlan-kicker{color:#76250f}.vlan-next h2{margin-bottom:0}.vlan-next-buttons{display:flex;align-items:center;gap:20px}.vlan-next-button{display:inline-flex;align-items:center;gap:15px;padding-bottom:7px;border-bottom:1px solid #76250f;color:#76250f!important;font-size:11px}@media(max-width:850px){.vlan-intro,.vlan-principles,.tag-section,.terminal-layout,.diagnose-section,.quiz-section{display:block}.segment-map,.principle-grid,.frame-inspector,.config-console,.diagnose-content,.quiz-card{margin-top:40px}.terminal-practice-missions{grid-template-columns:1fr}.vlan-next{display:block}.vlan-next-buttons{display:flex;flex-wrap:wrap;margin-top:45px}}@media(max-width:600px){.vlan-nav{padding:0 14px}.vlan-nav>span:last-child{display:none}.vlan-intro,.vlan-section{padding:70px 18px}.vlan-intro h1,.vlan-section-title h2,.quiz-section h2,.vlan-next h2{font-size:3.25rem}.principle-grid,.port-grid,.diagnose-cases{display:block}.principle-grid article,.port-card,.diagnose-cases button{border-bottom:1px solid var(--vlan-line)}.frame-selector{overflow-x:auto}.frame-notes{grid-template-columns:1fr 1fr}.gateway-controls{align-items:flex-start}.gateway-controls>span{width:100%}.vlan-create{flex-wrap:wrap}.vlan-create input:nth-of-type(2){width:100%}.terminal-port-selector{margin-left:0;width:100%;padding:8px 16px}}@media(prefers-reduced-motion:reduce){.vlan-page *{scroll-behavior:auto!important;transition:none!important}}.dhcp-page{--dhcp-ink:#18201d;--dhcp-paper:#f4f6f0;--dhcp-line:#d2d9d0;--dhcp-muted:#68736c;--dhcp-green:#1e8a58;--dhcp-lime:#dcedc8;--dhcp-yellow:#f1d66b;min-height:100vh;color:var(--dhcp-ink);background:var(--dhcp-paper);font-family:Arial,Helvetica,sans-serif}.dhcp-page,.dhcp-page *{box-sizing:border-box}.dhcp-page a{color:inherit;text-decoration:none}.dhcp-page button,.dhcp-page input,.dhcp-page select{font:inherit}.dhcp-page button{cursor:pointer}.dhcp-nav{display:flex;align-items:center;justify-content:space-between;min-height:48px;padding:0 25px;border-bottom:1px solid var(--dhcp-line);color:var(--dhcp-muted);font:9px Courier New,monospace}.dhcp-back{display:inline-flex;align-items:center;gap:8px;color:var(--dhcp-ink)!important;font:600 10px Arial,sans-serif}.dhcp-back:hover{color:var(--dhcp-green)!important}.dhcp-kicker{color:var(--dhcp-muted);font:9px/1.3 Courier New,monospace;letter-spacing:.08em}.dhcp-hero{display:grid;grid-template-columns:minmax(0,1fr) minmax(350px,500px);gap:80px;align-items:center;max-width:1440px;margin:auto;padding:110px clamp(28px,7vw,112px) 100px;border-bottom:1px solid var(--dhcp-line)}.dhcp-hero h1,.dhcp-section-title h2,.explain-block h2,.troubleshooting-section h2,.dhcp-next h2{margin:22px 0 27px;font-size:clamp(3.2rem,6.4vw,7rem);line-height:.86;letter-spacing:-.08em}.dhcp-hero h1 em,.dhcp-section-title h2 em,.explain-block h2 em,.troubleshooting-section h2 em,.dhcp-next h2 em{font-style:normal;font-weight:400}.dhcp-hero p,.dhcp-section-title>p{max-width:450px;color:#5d6962;font-size:14px;line-height:1.45}.service-orbit{position:relative;min-height:360px;border:1px solid var(--dhcp-line);background:#e8eee4}.orbit-center,.orbit-node{position:absolute;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:6px;border:1px solid var(--dhcp-line);background:var(--dhcp-paper);text-align:center}.orbit-center{top:124px;left:calc(50% - 55px);width:110px;height:110px;border-radius:50%;color:var(--dhcp-green)}.orbit-center strong{font:700 19px Courier New,monospace}.orbit-center small,.orbit-node small{color:var(--dhcp-muted);font:8px Courier New,monospace}.orbit-node{width:100px;height:74px}.orbit-node strong{font:11px Courier 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New,monospace}.dora-actions{display:flex;gap:6px;margin-top:19px}.dora-actions button{display:inline-flex;align-items:center;gap:5px;padding:9px 8px;border:0;color:#fff;background:var(--dhcp-green);font:9px Courier New,monospace}.dora-actions button+button{color:var(--dhcp-ink);background:#fff}.dora-actions button:disabled{opacity:.45;cursor:not-allowed}.form-error{display:block;margin-top:12px;color:#b63424;font:9px Courier New,monospace}.dora-flow{position:relative}.dora-step{display:grid;grid-template-columns:40px 1fr;gap:14px;align-items:start;padding:16px 0;border-bottom:1px solid var(--dhcp-line);opacity:.42}.dora-step.is-done,.dora-step.is-active{opacity:1}.dora-step.is-active{padding-left:13px;border-left:3px solid var(--dhcp-green);background:#e7f2df}.dora-badge{display:grid;place-items:center;width:33px;height:33px;color:var(--dhcp-muted);border:1px solid var(--dhcp-line);border-radius:50%;font:700 12px Courier New,monospace}.is-done .dora-badge{color:#fff;background:var(--dhcp-green);border-color:var(--dhcp-green)}.dora-step strong{display:block;margin-bottom:5px;font:700 12px Courier New,monospace}.dora-step small{display:block;color:var(--dhcp-muted);font-size:11px;line-height:1.35}.dora-step code{display:block;margin-top:9px;color:var(--dhcp-green);font:9px Courier New,monospace}.dora-packet{display:flex;align-items:center;gap:9px;margin:13px 0;color:var(--dhcp-green);font:9px Courier New,monospace}.dora-packet i{width:80px;height:1px;background:var(--dhcp-green);animation:packet-dash .7s linear infinite}.lease-card{display:flex;align-items:flex-start;gap:9px;margin-top:18px;padding:16px;color:#23663d;background:#d7ecd1;font-size:11px}.lease-card p{margin:6px 0 0;color:#56725b;font-size:10px}@keyframes packet-dash{0%{transform:scaleX(.3);transform-origin:left}to{transform:scaleX(1);transform-origin:left}}.nat-section{background:#e9eee8}.nat-lab{padding:21px;background:#dfe9dc;border:1px solid var(--dhcp-line)}.nat-controls{display:grid;grid-template-columns:1fr 1fr 1fr 1fr 100px;gap:10px;align-items:end}.nat-toggle{display:flex;flex-direction:column;gap:7px;color:var(--dhcp-muted);font:9px Courier New,monospace}.nat-toggle button{padding:9px;color:#9b3424;background:#f3d9d2;border:1px solid #dda699;font:9px Courier New,monospace}.nat-toggle button.is-on{color:#21633b;background:#d1ead0;border-color:#97c19c}.translate-button{display:inline-flex;align-items:center;justify-content:center;gap:4px;min-height:36px;padding:7px;color:#fff;background:var(--dhcp-green);border:0;font:9px Courier New,monospace}.nat-path{display:flex;align-items:center;justify-content:center;gap:16px;margin:19px 0;padding:18px;background:var(--dhcp-ink);color:#c8dbca;text-align:center;font:9px Courier New,monospace}.nat-path i{width:70px;height:1px;background:var(--dhcp-green)}.nat-path strong{padding:7px;color:var(--dhcp-ink);background:var(--dhcp-yellow);font:10px Courier New,monospace}.nat-path 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#7b4a2e;color:#7b4a2e}.nat-packet-pill.is-wan{border-color:var(--dhcp-green);box-shadow:0 2px 0 var(--dhcp-green);color:var(--dhcp-green)}.nat-packet-pill.is-reply{border-color:#1e8a58;box-shadow:0 2px #1e8a58;color:#1e8a58;background:#f0fdf4}.nat-packet-pill.is-drop{border-color:#dc2626;box-shadow:0 2px #dc2626;color:#dc2626;background:#fef2f2}.nat-port-inspector{display:grid;grid-template-columns:repeat(4,1fr);gap:1px;background:var(--dhcp-line);border:1px solid var(--dhcp-line);margin-top:16px}.inspector-col{padding:10px 14px;background:var(--dhcp-paper)}.inspector-col strong{display:block;font:700 9px Courier New,monospace;color:var(--dhcp-muted);text-transform:uppercase;margin-bottom:3px}.inspector-col code{font:11px Courier New,monospace;color:var(--dhcp-ink)}.inspector-col.is-highlight{background:#fff1e9}.inspector-col.is-highlight code{color:var(--dhcp-green);font-weight:700}.nat-presets-row{display:flex;align-items:center;flex-wrap:wrap;gap:6px;margin-top:12px;font:9px Courier 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ease}.nat-step-btn:hover:not(:disabled){border-color:var(--dhcp-ink);background:var(--dhcp-paper)}.nat-step-btn.is-primary{background:var(--dhcp-green);border-color:var(--dhcp-green);color:#fff}.nat-step-btn.is-primary:hover:not(:disabled){opacity:.9}.nat-step-btn:disabled{opacity:.45;cursor:not-allowed}.nat-row.is-active-mapping{background:#fff3ec;font-weight:700}.nat-row-badge{display:inline-block;padding:2px 5px;font:700 8px Courier New,monospace;text-transform:uppercase}.nat-row-badge.active{background:#d1ead0;color:#21633b}.nat-row-badge.returning{background:#fef3c7;color:#92400e}.nat-row-badge.established{background:#ffedd5;color:#c2410c}@media(max-width:900px){.nat-topology-grid{grid-template-columns:1fr;gap:12px}.nat-cable-track{height:36px}.nat-port-inspector{grid-template-columns:1fr 1fr}}.dora-interactive-stage{display:flex;flex-direction:column;gap:14px}.dora-pipeline-bar{display:grid;grid-template-columns:repeat(4,1fr);gap:1px;background:var(--dhcp-line);border:1px solid var(--dhcp-line)}.dora-pipeline-btn{display:flex;align-items:center;gap:8px;padding:10px 12px;background:var(--dhcp-paper);border:none;cursor:pointer;transition:all .15s ease;text-align:left}.dora-pipeline-btn:hover{background:#fdf5f0}.dora-pipeline-btn.is-active{background:#fff;box-shadow:inset 0 -3px 0 var(--dhcp-green)}.dora-pipeline-btn.is-done{background:#f4faf4}.dora-pipeline-badge{display:grid;place-items:center;width:26px;height:26px;font:700 12px Courier New,monospace;background:#fff;color:var(--dhcp-muted);border:1px solid var(--dhcp-line);border-radius:50%;flex-shrink:0}.dora-pipeline-btn.is-active .dora-pipeline-badge{background:var(--dhcp-green);color:#fff;border-color:var(--dhcp-green)}.dora-pipeline-btn.is-done .dora-pipeline-badge{background:#1e8a58;color:#fff;border-color:#1e8a58}.dora-pipeline-text strong{display:block;font-size:11px;font-family:Courier New,monospace;letter-spacing:-.02em;color:var(--dhcp-ink)}.dora-pipeline-text 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