/* ── SVG Canvas ──────────────────────────────────────────── */
.sim-svg {
  width: 100%;
  overflow: visible;
  display: block;
}

/* ── Edges / wires ──────────────────────────────────────── */
.edge {
  stroke: var(--gray-muted);
  stroke-linecap: round;
  fill: none;
  transition: stroke 0.3s;
}

.edge--active   { stroke: var(--green); }
.edge--inactive { stroke: var(--gray-muted); }
.edge--retrans  { stroke: var(--red); stroke-dasharray: 6 4; }
.edge--low      { stroke-width: 1.5; }
.edge--medium   { stroke-width: 2.5; }
.edge--high     { stroke-width: 4; }

.edge-hit-area {
  stroke: transparent;
  stroke-width: 16;
  fill: none;
  cursor: pointer;
}

/* Wire glow — applied briefly during L1 bit=1 transmission */
.wire--glow {
  stroke: var(--green);
  filter: drop-shadow(0 0 4px var(--green));
  transition: stroke 0.08s, filter 0.08s;
}

/* ── Nodes ───────────────────────────────────────────────── */
.node-group { cursor: pointer; }

/* Circle (end device) */
.node-circle {
  fill: #1a2035;
  stroke: var(--blue);
  stroke-width: 2;
  transition: stroke 0.3s, fill 0.3s;
  r: 26;
}

/* Hexagon (router) */
.node-hex {
  fill: #1a2035;
  stroke: var(--blue);
  stroke-width: 2;
  transition: stroke 0.3s, fill 0.3s;
}

/* Diamond (DNS) */
.node-diamond {
  fill: #1a2035;
  stroke: var(--blue);
  stroke-width: 2;
  transition: stroke 0.3s, fill 0.3s;
}

/* Rectangle (web server) */
.node-rect {
  fill: #1a2035;
  stroke: var(--blue);
  stroke-width: 2;
  transition: stroke 0.3s, fill 0.3s;
  rx: 5;
}

/* Active state */
.node-group.node--active .node-circle,
.node-group.node--active .node-hex,
.node-group.node--active .node-diamond,
.node-group.node--active .node-rect {
  stroke: var(--green);
  filter: drop-shadow(0 0 6px var(--green));
}

/* Killed state */
.node-group.node--killed .node-circle,
.node-group.node--killed .node-hex,
.node-group.node--killed .node-diamond,
.node-group.node--killed .node-rect {
  fill: #2a0a10;
  stroke: var(--red);
}

.node-group.node--killed .node-label {
  fill: var(--red);
}

/* Kill X overlay */
.node-kill-x {
  stroke: var(--red);
  stroke-width: 2.5;
  opacity: 0;
  transition: opacity 0.2s;
}
.node-group.node--killed .node-kill-x { opacity: 1; }

/* Highlight (SPOF) */
.node-group.node--spof .node-circle,
.node-group.node--spof .node-hex {
  stroke: var(--amber);
  filter: drop-shadow(0 0 8px var(--amber));
}

/* Pulse animation for active nodes */
@keyframes node-pulse {
  0%   { opacity: 0.6; r: 30; }
  100% { opacity: 0;   r: 42; }
}

.node-pulse-ring {
  fill: none;
  stroke: var(--green);
  stroke-width: 1.5;
  opacity: 0;
  pointer-events: none;
}

.node-group.node--active .node-pulse-ring {
  animation: node-pulse 1.8s ease-out infinite;
}

/* Node labels */
.node-label {
  fill: var(--text);
  font-family: var(--font-mono);
  font-size: 10px;
  text-anchor: middle;
  dominant-baseline: central;
  pointer-events: none;
  user-select: none;
}

.node-sublabel {
  fill: var(--text-muted);
  font-family: var(--font-mono);
  font-size: 9px;
  text-anchor: middle;
  dominant-baseline: central;
  pointer-events: none;
  user-select: none;
}

/* ── Packets ──────────────────────────────────────────────── */
.packet {
  rx: 3;
  width: 24px;
  height: 24px;
  transition: fill 0.1s;
  pointer-events: none;
}

.packet--blue   { fill: var(--blue);  filter: drop-shadow(0 0 4px var(--blue)); }
.packet--green  { fill: var(--green); filter: drop-shadow(0 0 4px var(--green)); }
.packet--red    { fill: var(--red);   filter: drop-shadow(0 0 4px var(--red)); }
.packet--yellow { fill: var(--yellow); filter: drop-shadow(0 0 4px var(--yellow)); }

.packet-label {
  fill: #0a0e1a;
  font-family: var(--font-mono);
  font-size: 7px;
  font-weight: 700;
  text-anchor: middle;
  dominant-baseline: central;
  pointer-events: none;
  user-select: none;
}

/* Drop X animation */
@keyframes packet-drop {
  0%   { opacity: 1; transform: scale(1); }
  50%  { opacity: 1; transform: scale(1.4); }
  100% { opacity: 0; transform: scale(0.5); }
}

.packet-drop {
  animation: packet-drop 0.45s ease-out forwards;
}

/* ── Flow dots on edges (L6) ────────────────────────────── */
@keyframes flow-dot {
  from { stroke-dashoffset: 20; }
  to   { stroke-dashoffset: 0; }
}

.edge--flowing {
  stroke-dasharray: 4 16;
  animation: flow-dot 0.6s linear infinite;
}

/* ── Handshake callout overlay ──────────────────────────── */
.handshake-callout {
  position: absolute;
  bottom: calc(100% + 8px);
  left: 50%;
  transform: translateX(-50%);
  background: #0d1120;
  border: 1px solid var(--blue);
  border-radius: var(--radius);
  padding: 0.5rem 0.75rem;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--blue);
  white-space: nowrap;
  pointer-events: none;
  z-index: 20;
  opacity: 0;
  transition: opacity 0.2s;
}
.handshake-callout.visible { opacity: 1; }

/* ── Banner overlay (connection established, etc.) ──────── */
.sim-banner {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  background: #00ff9d15;
  border: 1px solid var(--green);
  border-radius: var(--radius-lg);
  padding: 0.75rem 2rem;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--green);
  letter-spacing: 0.08em;
  text-align: center;
  pointer-events: none;
  z-index: 20;
  animation: banner-in 0.3s ease-out;
}

@keyframes banner-in {
  from { opacity: 0; transform: translate(-50%, -45%); }
  to   { opacity: 1; transform: translate(-50%, -50%); }
}

/* ── Bit stream display (L1) ────────────────────────────── */
.bit-stream {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  letter-spacing: 0.15em;
  color: var(--text-muted);
  min-height: 1.4em;
  word-break: break-all;
}

.bit-stream .bit-1 { color: var(--green); }
.bit-stream .bit-0 { color: var(--text-muted); }
.bit-stream .bit-pending { color: var(--gray-muted); }

/* ── Receiver panel ─────────────────────────────────────── */
.receiver-display {
  font-family: var(--font-mono);
  font-size: 1.1rem;
  color: var(--green);
  letter-spacing: 0.1em;
  min-height: 1.5em;
  word-break: break-all;
}

/* ── DNS hop timing ─────────────────────────────────────── */
.dns-hop-label {
  font-family: var(--font-mono);
  font-size: 9px;
  fill: var(--text-muted);
  text-anchor: middle;
  pointer-events: none;
}

.dns-timing {
  font-family: var(--font-mono);
  font-size: 9px;
  fill: var(--yellow);
  text-anchor: middle;
  pointer-events: none;
}

/* ── Fault tolerance result banner ──────────────────────── */
.ft-banner--ok   { border-color: var(--green); background: #00ff9d10; color: var(--green); }
.ft-banner--fail { border-color: var(--red);   background: #ff4d6d10; color: var(--red); }

/* ── L6 canvas wrapper ──────────────────────────────────── */
#l6-canvas-wrap {
  position: relative;
  flex: 1;
  overflow: hidden;
}

#l6-svg {
  width: 100%;
  height: 100%;
  cursor: crosshair;
}

/* Pending edge line (rubber-band) */
#pending-edge {
  stroke: var(--blue);
  stroke-width: 1.5;
  stroke-dasharray: 6 4;
  pointer-events: none;
}

/* ── ASCII table overlay ────────────────────────────────── */
.ascii-table-wrap {
  max-height: 260px;
  overflow-y: auto;
  border: 1px solid var(--gray-muted);
  border-radius: var(--radius-lg);
  background: #090d17;
}

/* ── Packet reorder animation ───────────────────────────── */
@keyframes packet-reorder {
  0%   { transform: translateY(0); }
  50%  { transform: translateY(-8px); }
  100% { transform: translateY(0); }
}

.reordering { animation: packet-reorder 0.4s ease; }

/* ── L4 reassembly display ──────────────────────────────── */
.reassembly-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0.5rem;
  margin-top: 0.5rem;
}

.reassembly-slot {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.25rem;
  padding: 0.5rem;
  border: 1px solid var(--gray-muted);
  border-radius: var(--radius);
  background: #0d1220;
  min-height: 56px;
}

.reassembly-slot.filled {
  border-color: var(--green);
  background: #00ff9d08;
}

.reassembly-slot-num {
  font-family: var(--font-mono);
  font-size: 0.6rem;
  color: var(--text-muted);
}

.reassembly-slot-content {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--green);
  word-break: break-all;
  text-align: center;
}