.cable-btn.down{background:#fff0f2;color:#b93545;border-color:#e3aab1}

/* V7 · topology learning overlays */
.logical-chip rect{fill:#fff;stroke:#aabfce;stroke-width:1.4}
.logical-chip text{font-size:11px;font-weight:900;fill:#405a70}
.logical-chip.warn rect{fill:#fff7e9;stroke:#e0a84a}
.logical-chip.warn text{fill:#9b6410}
.logical-chip.bad rect{fill:#fff0f2;stroke:#d98691}
.logical-chip.bad text{fill:#a52f3e}

.trace-path{display:none;fill:none;stroke-width:7;stroke-linecap:round;stroke-linejoin:round;pointer-events:none}
.trace-path.show{display:block}
.trace-request{stroke:#12a57e;opacity:.75;marker-end:url(#arrowRequest)}
.trace-reply{stroke:#2f7fd0;opacity:.8;stroke-dasharray:13 9;marker-end:url(#arrowReply)}
.trace-label{display:none;pointer-events:none;font-size:11px;font-weight:1000}
.trace-label.show{display:block}
.trace-label.req{fill:#08765d}.trace-label.rep{fill:#175da8}

.link-ifdown{
  stroke:#d98a00 !important;stroke-width:5 !important;stroke-dasharray:none !important;opacity:.9;
  filter:drop-shadow(0 0 3px rgba(217,138,0,.2))
}
.link-badge.ifdown rect{fill:#fff7e9;stroke:#dfa548}
.link-badge.ifdown text{fill:#9d650b}
.port-led{stroke:#fff;stroke-width:2}
.port-led.up{fill:#0ea77d}.port-led.down{fill:#d64252}
.port-led-label{font-size:9px;font-weight:1000;fill:#526a7c}

.arp-branch{display:none;filter:drop-shadow(0 0 6px rgba(14,167,125,.55))}
.arp-branch.show{display:block}
.arp-broadcast-label{display:none;font-size:11px;font-weight:1000;fill:#08765d}
.arp-broadcast-label.show{display:block}

.route-lookup-card{
  display:none;position:absolute;z-index:20;left:50%;top:55%;transform:translate(-50%,-50%);
  width:min(360px,76%);background:rgba(7,19,31,.96);color:#e8f3fa;border:1px solid #44657d;
  border-radius:15px;padding:13px 14px;box-shadow:0 18px 50px rgba(0,0,0,.28)
}
.route-lookup-card.show{display:block;animation:routePop .18s ease-out}
@keyframes routePop{from{opacity:0;transform:translate(-50%,-46%) scale(.97)}to{opacity:1;transform:translate(-50%,-50%) scale(1)}}
.route-lookup-card .r-head{display:flex;justify-content:space-between;gap:10px;align-items:center}
.route-lookup-card .r-head b{font-size:12px}.route-lookup-card .r-head span{font-size:9px;color:#6ce0bb;font-weight:1000}
.route-lookup-card .r-dst{font:12px/1.45 ui-monospace,SFMono-Regular,Consolas,monospace;margin-top:8px;color:#cce6f6}
.route-lookup-steps{display:grid;grid-template-columns:repeat(3,1fr);gap:6px;margin-top:9px}
.route-lookup-step{border:1px solid #294156;background:#0d2031;border-radius:9px;padding:8px}
.route-lookup-step b{display:block;font-size:9px;color:#84a8bf}.route-lookup-step span{display:block;font-size:10px;font-weight:900;margin-top:3px}
.route-lookup-step.fail{border-color:#7b3b45;background:#27141a}.route-lookup-step.fail span{color:#ffb2bd}

.physical-logical-note{
  display:flex;gap:8px;flex-wrap:wrap;margin-top:7px;font-size:9px;color:#708697
}
.physical-logical-note b{color:#425d72}

.live-event-strip{
  min-height:74px;margin-top:10px;border:1px solid #d5e2ea;background:#fff;border-radius:14px;
  display:grid;grid-template-columns:auto minmax(0,1fr) auto;gap:12px;align-items:center;padding:11px 13px;
  transition:border-color .18s,background .18s
}
.live-event-icon{
  width:38px;height:38px;border-radius:11px;display:grid;place-items:center;background:#eef3f7;
  color:#597185;font-size:12px;font-weight:1000
}
.live-event-main b{display:block;font-size:13px}
.live-event-main p{margin:3px 0 0;color:#6a8092;font-size:11px;line-height:1.55}
.live-event-kind{
  border-radius:999px;padding:6px 9px;background:#eef3f7;color:#607587;font-size:9px;font-weight:1000;
  letter-spacing:.06em;white-space:nowrap
}
.live-event-strip.arp{border-color:#a9d8c8;background:#f5fcf9}
.live-event-strip.arp .live-event-icon,.live-event-strip.arp .live-event-kind{background:#dff5ed;color:#08765d}
.live-event-strip.icmp{border-color:#b8d2ed;background:#f5f9fe}
.live-event-strip.icmp .live-event-icon,.live-event-strip.icmp .live-event-kind{background:#e5f0ff;color:#175da8}
.live-event-strip.route{border-color:#c8d5e0;background:#f7fafc}
.live-event-strip.route .live-event-icon,.live-event-strip.route .live-event-kind{background:#e8eef4;color:#365a74}
.live-event-strip.reply{border-color:#b8d2ed;background:#f5f9fe}
.live-event-strip.reply .live-event-icon,.live-event-strip.reply .live-event-kind{background:#e5f0ff;color:#175da8}
.live-event-strip.error{border-color:#e4b1b8;background:#fff5f6}
.live-event-strip.error .live-event-icon,.live-event-strip.error .live-event-kind{background:#ffe7ea;color:#ad3443}

.arp-broadcast-label{display:none !important}

@media(max-width:1000px){
  .flow{grid-template-columns:1fr 1fr}.details-grid{grid-template-columns:1fr}
  .meaning-grid{grid-template-columns:1fr 1fr}.concept-strip{grid-template-columns:1fr 1fr}
}
@media(max-width:720px){
  .wrap{padding:10px}.hero{padding:20px;border-radius:18px}.start-guide{grid-template-columns:1fr}
  .topology-shell{overflow-x:auto;overscroll-behavior-x:contain}
  .topology-shell svg{width:980px;max-width:none}
  .topology-tip::after{content:" · 모바일에서는 토폴로지를 좌우로 밀어서 확인하세요.";font-weight:800;color:#175da8}
  .coach{grid-template-columns:auto 1fr}.coach-next{display:none}
  .controls{grid-template-columns:1fr}.dest-btn{min-width:0;flex:1}.ping-btn{width:100%}
  .flow{grid-template-columns:1fr}.packet-grid{grid-template-columns:1fr 1fr}
  .advanced-actions{grid-template-columns:1fr}
  .meaning-grid{grid-template-columns:1fr}.concept-strip{grid-template-columns:1fr 1fr}
  .course-progress{grid-template-columns:1fr}.check-list{grid-template-columns:1fr}.completion-grid{grid-template-columns:1fr}
  .device-form-grid,.device-form-grid.router{grid-template-columns:1fr 1fr}.device-quick-grid{grid-template-columns:1fr 1fr}.cable-grid{grid-template-columns:1fr 1fr}.live-event-strip{grid-template-columns:auto 1fr}
  .compare-box{overflow:auto}.compare-table{min-width:680px}
  .lesson-tabs{margin-left:-2px;margin-right:-2px}
}


/* V9 · beginner-first basic / advanced view modes */
.view-mode-card{
  display:flex;justify-content:space-between;gap:16px;align-items:center;
  margin:12px 0 0;padding:13px 15px;background:#f8fbfd;border:1px solid #d5e2ea;
  border-radius:16px;box-shadow:var(--shadow)
}
.view-mode-copy{min-width:0}
.view-mode-copy strong{display:block;font-size:13px;color:#173b58}
.view-mode-copy span{display:block;margin-top:3px;color:#667e91;font-size:10px;line-height:1.5}
.view-mode-actions{display:flex;gap:7px;flex:0 0 auto}
.view-mode-btn{
  min-width:132px;border:1px solid #cfdae4;background:#fff;color:#456176;border-radius:11px;
  padding:8px 11px;text-align:left;cursor:pointer
}
.view-mode-btn b{display:block;font-size:11px}
.view-mode-btn small{display:block;margin-top:2px;color:#8093a5;font-size:8px}
.view-mode-btn.active,.view-mode-btn[aria-pressed="true"]{
  border-color:#2c759c;background:#edf7fb;color:#154e6d;box-shadow:inset 0 0 0 1px rgba(44,117,156,.08)
}
.view-mode-btn.active small,.view-mode-btn[aria-pressed="true"] small{color:#4b7187}

.legend-direction-note{
  flex-basis:100%;padding-top:5px;border-top:1px dashed #d8e2e9;color:#61798c;line-height:1.5
}
.legend-direction-note b{color:#36576e}

.neighbor-table-head{
  display:flex;align-items:center;justify-content:space-between;gap:12px
}
.neighbor-table-head.spaced{margin-top:18px}
.neighbor-table-head strong{min-width:0}
.neighbor-clear-btn{
  flex:0 0 auto;border:1px solid #cfdce5;background:#fff;color:#536e82;border-radius:9px;
  padding:6px 8px;font-size:9px;font-weight:900;cursor:pointer
}
.neighbor-clear-btn:hover{background:#f1f6f9;border-color:#aabfce}
.neighbor-clear-btn:active{transform:translateY(1px)}

.packet-stage-btn{min-width:155px}
.packet-stage-order{
  display:block!important;margin:0 0 4px!important;color:#6b8396!important;
  font-size:8px!important;font-weight:1000!important;letter-spacing:.08em!important
}
.packet-stage-type{
  display:inline-flex!important;margin:0!important;border-radius:999px;padding:3px 6px;
  background:#e8f2f8;color:#315f79!important;font-size:8px!important;font-weight:1000!important;letter-spacing:.05em
}
.packet-stage-type.arp-request{background:#e0f5ed;color:#08765d!important}
.packet-stage-type.arp-reply{background:#e7f0ff;color:#175da8!important}
.packet-stage-type.icmp-request{background:#f4edff;color:#6945a2!important}
.packet-stage-type.icmp-reply{background:#eef0ff;color:#4a58a8!important}
.packet-stage-name{display:block!important;margin-top:5px!important;color:#1f3f56!important;font-size:11px!important;font-weight:900!important}
.packet-stage-hop{display:block!important;margin-top:2px!important;color:#8093a5!important;font-size:9px!important;font-weight:600!important}

.recovery-mode-btn{
  display:inline-flex;align-items:center;justify-content:center;margin-top:9px;border:1px solid #c89b50;
  background:#fff;color:#79551c;border-radius:9px;padding:7px 10px;font-size:10px;font-weight:1000;cursor:pointer
}

/* Basic is always the first-load experience. Advanced details and mutation controls stay hidden. */
body[data-sim-mode="basic"] .advanced-only,
body[data-sim-mode="basic"] .details-grid,
body[data-sim-mode="basic"] .topology-tip,
body[data-sim-mode="basic"] .physical-logical-note,
body[data-sim-mode="basic"] .route-lookup-card{display:none!important}
body[data-sim-mode="basic"] .config-tag,
body[data-sim-mode="basic"] .config-tag-text{display:none!important}
body[data-sim-mode="basic"] .device-config-hit,
body[data-sim-mode="basic"] .topology-link,
body[data-sim-mode="basic"] .link-badge{pointer-events:none!important;cursor:default!important}
body[data-sim-mode="basic"] #deviceDrawer{display:none!important}

/* Mobile topology keeps its visual links, but configuration/link mutation is advanced-only. */
body[data-sim-mode="basic"] [data-m-device]{display:none!important}
body[data-sim-mode="basic"] [data-m-link]{pointer-events:none!important;cursor:default!important}

@media(max-width:720px){
  .view-mode-card{display:grid;grid-template-columns:1fr;gap:9px;padding:11px}
  .view-mode-actions{display:grid;grid-template-columns:1fr 1fr;width:100%}
  .view-mode-btn{min-width:0;width:100%}
  .neighbor-table-head{align-items:flex-start}
}
@media(max-width:420px){
  .view-mode-actions{grid-template-columns:1fr}
  .view-mode-btn{text-align:center}
}


/* V10 · education-first basic mode */
.beginner-key{
  max-width:1500px;margin:0 auto 12px;padding:11px 14px;display:flex;gap:8px 14px;
  align-items:center;flex-wrap:wrap;border:1px solid #cfe0d9;border-radius:13px;
  background:#f5fbf8;color:#4f6a60;font-size:11px;line-height:1.55
}
.beginner-key>b{color:#08765d;white-space:nowrap}
.beginner-key strong{color:#173b58}

.prediction-card{
  margin:0 0 12px;padding:16px;border:2px solid #c6d8e5;border-radius:16px;background:#fff
}
.prediction-copy small{display:block;color:#175da8;font-size:10px;font-weight:1000;letter-spacing:.04em}
.prediction-copy h2{margin:5px 0 4px;font-size:18px;line-height:1.4;letter-spacing:-.02em}
.prediction-copy p{margin:0;color:#6d8192;font-size:11px;line-height:1.55}
.prediction-options{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:8px;margin-top:12px}
.prediction-options button{
  min-height:48px;padding:10px 12px;border:1px solid #ccd9e4;border-radius:12px;
  background:#f9fbfd;color:#29465e;font-weight:900;text-align:center
}
.prediction-options button.selected{
  border-color:#175da8;background:#eaf3ff;color:#174f88;
  box-shadow:inset 0 0 0 1px rgba(23,93,168,.1)
}
.prediction-options button:disabled{cursor:default}
.prediction-feedback{
  display:grid;gap:3px;margin-top:11px;padding:11px 12px;border-radius:11px;
  border:1px solid #cfe0e8;background:#f6fafc;color:#4f687b;font-size:10px;line-height:1.5
}
.prediction-feedback[hidden]{display:none!important}
.prediction-feedback.correct{border-color:#add8c8;background:#eef9f4;color:#356556}
.prediction-feedback.incorrect{border-color:#efd1a7;background:#fff8ed;color:#76572d}
.prediction-feedback b{font-size:11px}
.prediction-feedback span{display:block}
.prediction-feedback p{margin:4px 0 0}

body[data-sim-mode="basic"] .destination-choice,
body[data-sim-mode="basic"] .result-title,
body[data-sim-mode="basic"] .flow,
body[data-sim-mode="basic"] .lesson-status .check-list,
body[data-sim-mode="basic"] .link-legend{display:none!important}

body[data-sim-mode="basic"] .controls{
  display:flex;justify-content:center;align-items:center;margin-top:12px
}
body[data-sim-mode="basic"] .ping-btn{min-width:330px}
body[data-sim-mode="basic"] .lesson-status{padding:10px 12px;background:#f9fbfd}
body[data-sim-mode="basic"] .lesson-status-head strong::after{
  content:" · 세부 조건은 고급 모드에서 확인";
  color:#8799a8;font-size:9px;font-weight:600
}
body[data-sim-mode="basic"] .explain{font-size:12px;padding:12px 14px}

@media(max-width:720px){
  .beginner-key{display:grid;margin:0 0 10px}
  .prediction-card{padding:13px;margin-bottom:10px}
  .prediction-copy h2{font-size:16px}
  .prediction-options{grid-template-columns:1fr}
  .prediction-options button{min-height:46px}
  body[data-sim-mode="basic"] .controls{display:grid;grid-template-columns:1fr}
  body[data-sim-mode="basic"] .ping-btn{min-width:0;width:100%}
}

.prediction-feedback-title{
  margin-bottom:3px;color:#175da8;font-size:9px;font-weight:1000;letter-spacing:.04em
}
.prediction-feedback.correct .prediction-feedback-title{color:#08765d}
.prediction-feedback.incorrect .prediction-feedback-title{color:#9a620e}


/* mode13 · completion navigation without scrolling */
.quick-next-bar{
  position:fixed;
  left:50%;
  bottom:14px;
  transform:translateX(-50%);
  z-index:80;
  width:min(760px,calc(100% - 28px));
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:14px;
  padding:11px 12px 11px 15px;
  border:1px solid #a9d8c8;
  border-radius:15px;
  background:rgba(247,252,250,.97);
  box-shadow:0 14px 36px rgba(17,48,66,.18);
  backdrop-filter:blur(10px)
}
.quick-next-bar[hidden]{display:none!important}
.quick-next-copy{min-width:0}
.quick-next-copy small{
  display:block;color:#08765d;font-size:9px;font-weight:1000;letter-spacing:.05em
}
.quick-next-copy strong{
  display:block;margin-top:2px;color:#294a40;font-size:11px;line-height:1.4
}
.quick-next-btn{
  flex:0 0 auto;min-height:42px;border:0;border-radius:11px;padding:10px 16px;
  background:#173b58;color:#fff;font-weight:1000
}
body.quick-next-visible{padding-bottom:84px}
body[data-sim-mode="advanced"] .quick-next-bar{display:none!important}
@media(max-width:560px){
  .quick-next-bar{bottom:8px;width:calc(100% - 16px);padding:9px 9px 9px 11px;gap:8px}
  .quick-next-copy strong{font-size:10px}
  .quick-next-btn{min-height:44px;padding:10px 13px}
  body.quick-next-visible{padding-bottom:78px}
}


/* mode15 · prediction first, action second */
body[data-sim-mode="basic"]:not(.prediction-selected) .controls{
  display:none!important;
}
body[data-sim-mode="basic"].prediction-selected .controls{
  animation:primaryActionReveal .18s ease-out both;
}
@keyframes primaryActionReveal{
  from{opacity:0;transform:translateY(-5px)}
  to{opacity:1;transform:translateY(0)}
}


/* mode16 · prediction interaction hardening */
.prediction-card{
  position:relative;
  z-index:90;
  pointer-events:auto;
}
.prediction-options,
.prediction-options button{
  position:relative;
  z-index:91;
  pointer-events:auto!important;
  touch-action:manipulation;
}