/* Network Simulator — theme + UI */
:root {
  --bg: #0f172a;
  --bg-2: #111c36;
  --panel: #1a2547;
  --panel-2: #243057;
  --ink: #e8eefc;
  --ink-dim: #9aa8c7;
  --accent: #5eead4;
  --accent-2: #818cf8;
  --warn: #fbbf24;
  --good: #34d399;
  --bad: #f87171;
  --line: rgba(255,255,255,0.08);
  --radius: 14px;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; height: 100%; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  overflow: hidden;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

button { font: inherit; color: inherit; }

.btn {
  background: var(--accent);
  color: var(--bg);
  border: none;
  padding: 8px 14px;
  font-weight: 600;
  border-radius: 8px;
  cursor: pointer;
  transition: transform 0.1s, opacity 0.2s;
  min-height: 36px;
}
.btn:hover { transform: translateY(-1px); }
.btn:active { transform: translateY(0); }
.btn.ghost {
  background: transparent;
  color: var(--ink);
  border: 1px solid var(--line);
}
.btn.ghost:hover { border-color: var(--accent); }
.btn.active { background: var(--bad); color: var(--bg); }
.btn:disabled { opacity: 0.4; cursor: not-allowed; }

/* App shell */
.app {
  display: grid;
  grid-template-rows: auto 1fr auto;
  height: 100vh;
}

.header {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 12px 20px 12px 62px;
  background: var(--bg-2);
  border-bottom: 1px solid var(--line);
}
.header h1 {
  font-size: 1.2rem;
  margin: 0;
  font-weight: 600;
}
.header h1 .accent { color: var(--accent); }
.header nav { margin-left: auto; display: flex; gap: 14px; align-items: center; }

.main {
  display: grid;
  grid-template-columns: 200px 1fr;
  overflow: hidden;
}
.main.main-with-tasks {
  grid-template-columns: 200px 1fr 300px;
}

.palette {
  background: var(--panel);
  border-right: 1px solid var(--line);
  padding: 12px;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.palette h3 {
  margin: 0 0 6px;
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--ink-dim);
}
.palette-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px 10px;
  background: var(--panel-2);
  border: 1px solid var(--line);
  border-radius: 8px;
  cursor: grab;
  user-select: none;
  touch-action: none;
  min-height: 48px;
}
.palette-item:hover { border-color: var(--accent); }
.palette-item.dragging { opacity: 0.5; }
.palette-item svg { width: 32px; height: 32px; flex-shrink: 0; }
.palette-item span { font-size: 0.9rem; }

.canvas-wrap {
  position: relative;
  overflow: hidden;
  background: var(--bg);
  display: flex;
  flex-direction: column;
  min-height: 0;
}
.canvas-scroll {
  flex: 1;
  overflow: auto;
  position: relative;
  min-height: 0;
}
.canvas-scroll #canvas { display: block; }
.toolbar {
  position: static;
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
  background: var(--panel);
  padding: 8px 12px;
  border-bottom: 1px solid var(--line);
  flex-shrink: 0;
}
.toolbar .btn { padding: 6px 12px; min-height: 32px; font-size: 0.88rem; }

#canvas {
  display: block;
  cursor: default;
  touch-action: none;
}
#canvas.delete-mode { cursor: crosshair; }
#canvas.lan-draw { cursor: crosshair; }

.statusbar {
  background: var(--bg-2);
  border-top: 1px solid var(--line);
  padding: 8px 16px;
  font-size: 0.88rem;
  color: var(--ink-dim);
  min-height: 36px;
  display: flex;
  align-items: center;
  gap: 12px;
}
.statusbar.good { color: var(--good); }
.statusbar.bad { color: var(--bad); }
.statusbar.warn { color: var(--warn); }

/* Empty state */
.empty-hint {
  position: absolute;
  top: 50%; left: 50%;
  transform: translate(-50%, -50%);
  color: var(--ink-dim);
  opacity: 0.5;
  font-size: 1rem;
  pointer-events: none;
  transition: opacity 0.5s;
  text-align: center;
}
.empty-hint.hidden { opacity: 0; }

/* Popups */
.popup {
  position: absolute;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 8px;
  min-width: 160px;
  z-index: 100;
  box-shadow: 0 8px 24px rgba(0,0,0,0.4);
  font-size: 0.9rem;
}
.popup button {
  display: block;
  width: 100%;
  text-align: left;
  background: transparent;
  border: none;
  color: var(--ink);
  padding: 8px 10px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.9rem;
}
.popup button:hover { background: var(--panel-2); }
.popup button.danger { color: var(--bad); }
.popup hr { border: none; border-top: 1px solid var(--line); margin: 4px 0; }
.popup label { display: block; padding: 4px 10px; color: var(--ink-dim); font-size: 0.8rem; }
.popup select, .popup input[type="text"] {
  width: 100%;
  background: var(--bg-2);
  color: var(--ink);
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 6px 8px;
  font: inherit;
  font-size: 0.9rem;
}

.tooltip {
  position: absolute;
  background: var(--panel-2);
  border: 1px solid var(--accent);
  color: var(--ink);
  padding: 6px 10px;
  border-radius: 6px;
  font-size: 0.82rem;
  pointer-events: none;
  z-index: 200;
  white-space: nowrap;
  box-shadow: 0 4px 12px rgba(0,0,0,0.4);
}

.explain-panel {
  position: absolute;
  right: 10px;
  bottom: 10px;
  width: 320px;
  background: var(--panel);
  border: 1px solid var(--bad);
  border-radius: 10px;
  padding: 14px;
  z-index: 50;
  box-shadow: 0 8px 24px rgba(0,0,0,0.5);
  transform: translateX(360px);
  transition: transform 0.3s;
}
.explain-panel.visible { transform: translateX(0); }
.explain-panel h4 { margin: 0 0 6px; color: var(--bad); font-size: 0.95rem; }
.explain-panel p { margin: 0 0 8px; font-size: 0.88rem; color: var(--ink-dim); }
.explain-panel .close {
  position: absolute;
  top: 8px; right: 8px;
  background: transparent;
  border: none;
  color: var(--ink-dim);
  cursor: pointer;
  font-size: 1.2rem;
}

/* Challenges page */
.canvas-column {
  display: flex;
  flex-direction: column;
  min-width: 0;
  min-height: 0;
  overflow: hidden;
}
.canvas-column > .canvas-wrap { flex: 1; min-height: 0; }
.task-panel {
  background: var(--panel);
  border-left: 1px solid var(--line);
  padding: 14px 16px;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 14px;
  min-width: 0;
}
.task-current {
  display: flex;
  align-items: flex-start;
  gap: 20px;
  padding: 12px 18px;
  background: var(--panel);
  border-bottom: 1px solid var(--line);
  flex-shrink: 0;
}
.task-current-text { flex: 1; min-width: 0; display: flex; flex-direction: column; gap: 4px; }
.task-current-text h2 { margin: 0; font-size: 1.05rem; }
.task-current-text .brief { color: var(--ink-dim); font-size: 0.88rem; margin: 0; line-height: 1.35; }
.task-reqs[hidden] { display: none; }
.task-reqs {
  margin-top: 6px;
  border: 1px solid var(--line);
  border-left: 3px solid var(--accent);
  border-radius: 8px;
  background: rgba(94, 234, 212, 0.05);
  padding: 6px 10px 8px;
  max-height: 168px;
  overflow-y: auto;
  /* Reserve the scrollbar track so the list text doesn't shift when a longer
     challenge makes the box scrollable. */
  scrollbar-gutter: stable;
}
.task-reqs summary {
  cursor: pointer;
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--accent);
  list-style: none;
  user-select: none;
}
.task-reqs summary::-webkit-details-marker { display: none; }
.task-reqs ul {
  margin: 6px 0 2px;
  padding-left: 18px;
  display: grid;
  gap: 3px;
}
.task-reqs li {
  color: var(--ink);
  font-size: 0.82rem;
  line-height: 1.35;
}
/* Fixed-width column so a long feedback message can never squeeze the brief
   and requirements checklist to a different width. */
.task-current-controls {
  display: flex;
  flex-direction: column;
  align-items: stretch;
  gap: 6px;
  flex: 0 0 260px;
  width: 260px;
}
.task-current .actions { display: flex; gap: 8px; align-items: center; }
.task-current .actions .btn { flex: 1; white-space: nowrap; }
.task-current .feedback {
  font-weight: 500;
  font-size: 0.85rem;
  line-height: 1.35;
  /* Reserve space for ~3 lines so the panel height stays steady as messages
     appear, disappear and change length. */
  min-height: 3.6em;
  max-height: 5.4em;
  overflow-y: auto;
  text-align: left;
  overflow-wrap: anywhere;
}
.task-current .feedback.good { color: var(--good); }
.task-current .feedback.bad  { color: var(--bad); }

.task-list { display: flex; flex-direction: column; gap: 2px; }
.task-list h2 { margin: 4px 0; font-size: 0.78rem; text-transform: uppercase; letter-spacing: 0.1em; color: var(--ink-dim); }
.task-list h3 { margin: 10px 0 4px; font-size: 0.72rem; text-transform: uppercase; letter-spacing: 0.1em; color: var(--accent-2); }

.challenge-link {
  display: block;
  padding: 8px 10px;
  border-radius: 8px;
  color: var(--ink);
  font-size: 0.88rem;
  cursor: pointer;
  border: 1px solid transparent;
  margin-bottom: 4px;
  text-decoration: none;
}
.challenge-link:hover { background: var(--panel-2); text-decoration: none; }
.challenge-link.active { background: var(--panel-2); border-color: var(--accent); }
.challenge-link .tick { color: var(--good); margin-right: 6px; }
.challenge-link .tick.empty { color: var(--ink-dim); opacity: 0.4; }

/* SVG element styles */
.device-group { cursor: grab; }
.device-group.dragging { cursor: grabbing; }
.device-body {
  fill: var(--panel-2);
  stroke: var(--accent);
  stroke-width: 1.5;
}
.device-icon { stroke: var(--accent); stroke-width: 1.5; fill: none; stroke-linecap: round; stroke-linejoin: round; }
.device-label {
  fill: var(--ink);
  font-family: -apple-system, sans-serif;
  font-size: 11px;
  text-anchor: middle;
  pointer-events: none;
}
.device-label.editing { display: none; }

.port {
  fill: var(--bg);
  stroke: var(--ink-dim);
  stroke-width: 1.2;
  cursor: crosshair;
}
.port.used { fill: var(--accent); stroke: var(--accent); }
.port.flash-bad { fill: var(--bad); stroke: var(--bad); }
.port.flash-active { fill: var(--good); stroke: var(--good); }

.status-light { stroke: rgba(0,0,0,0.4); stroke-width: 0.6; }
.status-light.off { fill: #44506b; }
.status-light.amber { fill: var(--warn); }
.status-light.green { fill: var(--good); }

.wire {
  fill: none;
  stroke: #6b7896;
  stroke-width: 2;
  pointer-events: stroke;
  cursor: pointer;
}
.wire.wireless { stroke: var(--accent); stroke-dasharray: 6 4; }
.wire.internet { stroke: var(--accent-2); stroke-dasharray: 8 5; }
.wire.success { stroke: var(--good); stroke-width: 3; }
.wire.fail { stroke: var(--bad); stroke-width: 3; }
.wire.rubber { pointer-events: none; opacity: 0.7; }

.lan-box {
  fill: rgba(94, 234, 212, 0.04);
  stroke: var(--accent);
  stroke-width: 1.2;
  rx: 10;
  cursor: move;
}
.lan-label-bg {
  fill: var(--accent);
}
.lan-label {
  fill: var(--bg);
  font-size: 11px;
  font-weight: 600;
  pointer-events: none;
}
.lan-handle {
  fill: var(--accent);
  stroke: var(--bg);
  stroke-width: 1;
  cursor: nwse-resize;
}

.wan-box {
  fill: rgba(129, 140, 248, 0.03);
  stroke: var(--accent-2);
  stroke-width: 1.5;
  stroke-dasharray: 10 6;
  rx: 14;
  cursor: move;
  pointer-events: stroke;
}
.wan-label-bg { fill: var(--accent-2); cursor: move; }
.wan-label { fill: var(--bg); font-size: 11px; font-weight: 700; pointer-events: none; }

.wap-coverage {
  fill: rgba(94, 234, 212, 0.08);
  stroke: var(--accent);
  stroke-width: 1;
  stroke-dasharray: 3 3;
  pointer-events: none;
}

.cloud-group { cursor: grab; }
.cloud-group:active { cursor: grabbing; }
.cloud-body {
  fill: rgba(129, 140, 248, 0.10);
  stroke: var(--accent-2);
  stroke-width: 2.5;
  filter: drop-shadow(0 0 12px rgba(129, 140, 248, 0.35));
}
.globe-lines * {
  fill: none;
  stroke: var(--accent-2);
  stroke-width: 1.6;
  opacity: 0.85;
}
.cloud-label {
  fill: var(--ink);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-anchor: middle;
  pointer-events: none;
}

.uplink-halo  { fill: none; stroke: var(--accent-2); stroke-width: 6;   opacity: 0.18; stroke-linecap: round; }
.uplink-line  { fill: none; stroke: var(--accent-2); stroke-width: 2.5; stroke-linecap: round; stroke-dasharray: 10 6; }
.uplink-line.uplink-flow { animation: uplinkFlow 1.4s linear infinite; }
@keyframes uplinkFlow { to { stroke-dashoffset: -16; } }

.internet-toggle { cursor: pointer; }
.internet-toggle .track {
  fill: var(--good);
  stroke: none;
  transition: fill 0.2s ease;
}
.internet-toggle.off .track { fill: #4b5563; }
.internet-toggle .knob {
  fill: #ffffff;
  stroke: rgba(0,0,0,0.15);
  stroke-width: 0.5;
  filter: drop-shadow(0 1px 1.5px rgba(0,0,0,0.35));
  transition: cx 0.2s ease;
}

.packet-dot {
  fill: var(--good);
  stroke: white;
  stroke-width: 1.5;
  filter: drop-shadow(0 0 6px var(--good));
  pointer-events: none;
}
.packet-dot.request  { fill: #a78bfa; filter: drop-shadow(0 0 8px #a78bfa); }
.packet-dot.response { fill: var(--good); filter: drop-shadow(0 0 8px var(--good)); }

.pulse-success {
  animation: pulse-good 0.6s ease-out;
}
@keyframes pulse-good {
  0% { transform: scale(1); }
  50% { transform: scale(1.2); }
  100% { transform: scale(1); }
}

.label-edit-input {
  position: absolute;
  background: var(--bg-2);
  color: var(--ink);
  border: 1px solid var(--accent);
  border-radius: 4px;
  padding: 2px 6px;
  font: inherit;
  font-size: 11px;
  text-align: center;
  z-index: 50;
}

/* Port-count dialog */
.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.5);
  z-index: 500;
  display: flex;
  align-items: center;
  justify-content: center;
}
.modal {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 20px;
  min-width: 240px;
  box-shadow: 0 12px 32px rgba(0,0,0,0.5);
}
.modal h3 { margin: 0 0 12px; font-size: 1rem; }
.modal .opts { display: flex; gap: 6px; flex-wrap: wrap; margin-bottom: 12px; }
.modal .opts button {
  flex: 1;
  background: var(--panel-2);
  color: var(--ink);
  border: 1px solid var(--line);
  padding: 10px;
  border-radius: 8px;
  cursor: pointer;
  font-weight: 600;
}
.modal .opts button:hover { border-color: var(--accent); }
.modal .actions { display: flex; gap: 8px; justify-content: flex-end; }

svg.dragging-device,
svg.dragging-device .device-group { cursor: grabbing !important; }

.palette-ghost {
  position: fixed;
  pointer-events: none;
  width: 56px;
  height: 56px;
  transform: translate(-50%, -50%);
  opacity: 0.8;
  z-index: 1000;
  filter: drop-shadow(0 4px 8px rgba(0,0,0,0.4));
}
.palette-ghost svg { width: 100%; height: 100%; }
body.palette-dragging,
body.palette-dragging .palette-item { cursor: grabbing !important; }

.packet-dot.copy { fill: var(--warn, #f59e0b); opacity: 0.85; }

.reject-x line {
  stroke: var(--bad);
  stroke-width: 4;
  stroke-linecap: round;
  filter: drop-shadow(0 0 6px var(--bad));
  transform-origin: center;
  transform-box: fill-box;
  animation: rejectXIn 1s ease-out forwards;
  opacity: 0;
}
@keyframes rejectXIn {
  0%   { opacity: 0; transform: scale(0.4); }
  20%  { opacity: 1; transform: scale(1.15); }
  60%  { opacity: 1; transform: scale(1); }
  100% { opacity: 0; transform: scale(1); }
}
.reject-tag rect { fill: var(--bad); filter: drop-shadow(0 2px 4px rgba(0,0,0,0.35)); }
.reject-tag text {
  fill: #fff;
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.04em;
  pointer-events: none;
}
.device-group.rejecting .dev-inner {
  animation: rejectShake 0.45s ease-in-out;
  transform-origin: center;
  transform-box: fill-box;
}
@keyframes rejectShake {
  0%, 100% { transform: translate(0, 0); }
  15% { transform: translate(-3px, 0); }
  35% { transform: translate(4px, 0); }
  55% { transform: translate(-3px, 0); }
  80% { transform: translate(2px, 0); }
}

.zoom-controls {
  position: absolute;
  bottom: 14px;
  right: 14px;
  display: flex;
  align-items: center;
  gap: 4px;
  background: var(--panel);
  padding: 4px;
  border: 1px solid var(--line);
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.3);
  z-index: 20;
}
.zoom-controls .btn {
  padding: 2px 10px;
  min-width: 32px;
  min-height: 28px;
  font-size: 1.1rem;
  font-weight: 600;
}
.zoom-controls .zoom-level {
  min-width: 44px;
  text-align: center;
  font-size: 0.82rem;
  color: var(--ink-dim);
  font-variant-numeric: tabular-nums;
}

.sim-toast {
  position: absolute;
  left: 50%;
  top: 70px;
  transform: translate(-50%, -8px);
  background: var(--panel-2, #1f2937);
  color: var(--ink, #f9fafb);
  padding: 10px 16px;
  border-radius: 8px;
  font-weight: 600;
  font-size: 0.95rem;
  box-shadow: 0 6px 18px rgba(0,0,0,0.35);
  border: 1px solid var(--line, #374151);
  opacity: 0;
  transition: opacity 0.2s ease, transform 0.2s ease;
  pointer-events: none;
  z-index: 50;
  white-space: nowrap;
}
.sim-toast.good { background: var(--good, #34d399); color: #0b1220; border-color: transparent; }
.sim-toast.bad  { background: var(--bad, #f87171); color: #0b1220; border-color: transparent; }
.sim-toast.warn { background: var(--warn, #f59e0b); color: #0b1220; border-color: transparent; }
.sim-toast.request { background: #a78bfa; color: #0b1220; border-color: transparent; }
.sim-toast.show { opacity: 1; transform: translate(-50%, 0); }

@media (max-width: 900px) {
  .main.main-with-tasks { grid-template-columns: 200px 1fr; }
  .task-panel { display: none; }
}
@media (max-width: 700px) {
  .main { grid-template-columns: 1fr; }
  .main.main-with-tasks { grid-template-columns: 1fr; }
  .palette { flex-direction: row; overflow-x: auto; }
  /* Stack the task header on narrow screens rather than keeping a fixed
     260px column that would crowd out the brief. */
  .task-current { flex-direction: column; align-items: stretch; gap: 10px; }
  .task-current-controls { flex: 1 1 auto; width: auto; }
  .task-current .feedback { min-height: 1.2em; max-height: none; }
}