:root {
  --sim-bg: var(--bg-main, #050A07);
  --sim-panel: var(--bg-card, #0D1811);
  --sim-panel-2: var(--bg-surface-2, #14241B);
  --sim-line: var(--line-base, #1B3224);
  --sim-accent: var(--accent-primary, #00E676);
  --sim-volt: var(--accent-secondary, #00FF87);
  --brand-primary: var(--accent-primary, #00E676);
  --brand-volt: var(--accent-secondary, #00FF87);
  --brand-forest: var(--bg-surface-3, #0D2616);
  --text-dim: var(--text-dim, #94A3B8);
  --text-light: var(--text-main, #E2E8F0);
  --font-editorial: 'Oswald', sans-serif;
  --font-display: 'Plus Jakarta Sans', sans-serif;
  --font-mono: 'JetBrains Mono', monospace;
}

body.sim-center-body {
  background: var(--sim-bg);
  color: var(--text-contrast, #FFFFFF);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
  font-family: var(--font-display);
}

/* Top Universal Hub Header */
.sim-hub-header {
  background: var(--header-bg, #08110B);
  border-bottom: 2px solid var(--sim-line);
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(12px);
}

.sim-hub-topbar {
  max-width: 1600px;
  margin: 0 auto;
  padding: 8px 16px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: nowrap;
}

.sim-hub-brand {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  flex-shrink: 0;
}

.sim-hub-crest {
  width: 34px;
  height: 40px;
  background: linear-gradient(145deg, #0D2616, #061109);
  border: 1.5px solid var(--sim-accent);
  clip-path: polygon(0 0, 100% 0, 100% 75%, 50% 100%, 0 75%);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 0 12px rgba(0, 230, 118, 0.35);
  flex-shrink: 0;
}

.sim-hub-crest svg {
  width: 17px;
  height: 17px;
  fill: var(--sim-accent);
}

.sim-hub-title {
  font-family: var(--font-editorial);
  font-size: 18px;
  font-weight: 800;
  color: #FFF;
  text-transform: uppercase;
  letter-spacing: 1px;
  line-height: 1.1;
  white-space: nowrap;
}

.sim-hub-title span {
  color: var(--sim-accent);
}

.sim-hub-subtitle {
  font-size: 10px;
  color: var(--text-dim);
  font-weight: 600;
  letter-spacing: 0.8px;
  text-transform: uppercase;
  white-space: nowrap;
}

/* Tabs Navigation */
.sim-tabs-strip {
  display: flex;
  gap: 4px;
  background: var(--bg-surface-2, #050D07);
  padding: 4px;
  border: 1px solid var(--sim-line);
  border-radius: 6px;
  overflow-x: auto;
  max-width: 100%;
  flex-shrink: 1;
  min-width: 0;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
}
.sim-tabs-strip::-webkit-scrollbar { display: none; }

.hub-tab-btn {
  background: transparent;
  border: 1px solid transparent;
  color: var(--text-dim);
  font-family: var(--font-editorial);
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  padding: 7px 12px;
  border-radius: 4px;
  cursor: pointer;
  white-space: nowrap;
  transition: all 0.2s ease;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  flex-shrink: 0;
}

.hub-tab-btn:hover {
  background: var(--sim-panel-2);
  color: var(--text-contrast, #FFF);
}

.hub-tab-btn.active {
  background: var(--sim-accent);
  color: var(--btn-text, #03140A);
  border-color: var(--sim-accent);
  box-shadow: 0 0 14px rgba(var(--accent-rgb, 0, 230, 118), 0.4);
}

.hub-tab-btn .badge-count {
  font-family: var(--font-mono);
  font-size: 9px;
  background: rgba(0,0,0,0.3);
  color: inherit;
  padding: 1px 5px;
  border-radius: 3px;
}

.hub-actions {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-shrink: 0;
}

.hub-btn {
  background: var(--sim-panel);
  border: 1px solid var(--sim-line);
  color: #FFF;
  font-family: var(--font-display);
  font-size: 11.5px;
  font-weight: 700;
  padding: 6px 12px;
  border-radius: 4px;
  cursor: pointer;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: all 0.15s ease;
  white-space: nowrap;
}

.hub-btn:hover {
  border-color: var(--sim-accent);
  color: var(--sim-accent);
}

/* Hub Responsive Breakpoints */
@media (max-width: 1200px) {
  .sim-hub-topbar { padding: 6px 12px; gap: 8px; }
  .hub-tab-btn { padding: 6px 10px; font-size: 11px; }
  .sim-hub-title { font-size: 16px; }
  .sim-hub-subtitle { display: none; }
}

@media (max-width: 900px) {
  .sim-hub-crest { width: 28px; height: 32px; }
  .sim-hub-crest svg { width: 14px; height: 14px; }
  .sim-hub-title { font-size: 14px; }
  .hub-btn .hub-btn-lbl { display: none; }
  .hub-btn { padding: 6px 8px; }
  .hub-tab-btn { padding: 5px 8px; font-size: 10.5px; }
}

@media (max-width: 640px) {
  .sim-hub-brand div { display: none; }
  .sim-hub-topbar { padding: 4px 6px; gap: 6px; }
}

/* Main Tab Content Viewport */
.sim-viewport-container {
  flex: 1;
  width: 100%;
  position: relative;
  background: #020603;
  display: flex;
  flex-direction: column;
}

.sim-tab-panel {
  display: none;
  width: 100%;
  height: 100%;
  flex: 1;
  animation: fadeIn 0.25s ease;
}

.sim-tab-panel.active {
  display: flex;
  flex-direction: column;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(4px); }
  to { opacity: 1; transform: translateY(0); }
}

/* 3D Embed Iframe */
.sim-fullscreen-frame {
  width: 100%;
  height: calc(100vh - 65px);
  min-height: 600px;
  border: none;
  display: block;
  background: #050A07;
}

/* 2D Interactive Tools Layout inside Tab Panels */
.tool-tab-content {
  max-width: 1200px;
  width: 100%;
  margin: 0 auto;
  padding: 40px 20px 80px;
}

.tool-tab-header {
  margin-bottom: 28px;
  border-bottom: 1px solid var(--sim-line);
  padding-bottom: 16px;
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  flex-wrap: wrap;
  gap: 12px;
}

.tool-tab-header h2 {
  font-family: var(--font-editorial);
  font-size: 28px;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: #FFF;
}

.tool-tab-header p {
  font-size: 13px;
  color: var(--text-dim);
  margin-top: 4px;
}

.arena-badge-live {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  color: var(--sim-accent);
  background: rgba(0, 230, 118, 0.1);
  border: 1px solid rgba(0, 230, 118, 0.3);
  padding: 4px 10px;
  border-radius: 4px;
}

.status-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--sim-accent);
  box-shadow: 0 0 6px var(--sim-accent);
}

.tool-card {
  background: var(--sim-panel);
  border: 1px solid var(--sim-line);
  border-top: 3px solid var(--sim-accent);
  border-radius: 8px;
  padding: 24px;
  box-shadow: 0 10px 30px rgba(0,0,0,0.5);
}

.subnet-form .input-row {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.form-field {
  display: flex;
  flex-direction: column;
  gap: 6px;
  flex: 1;
}

.form-label {
  font-size: 12px;
  font-weight: 700;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.arsenal-input {
  background: #060B08;
  border: 1px solid var(--sim-line);
  border-radius: 4px;
  color: #FFF;
  font-family: var(--font-mono);
  font-size: 14px;
  padding: 10px 12px;
  outline: none;
  transition: border-color 0.2s;
}

.arsenal-input:focus {
  border-color: var(--sim-accent);
  box-shadow: 0 0 8px rgba(0, 230, 118, 0.3);
}

.preset-pills {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-top: 14px;
}

.preset-pill {
  background: var(--sim-panel-2);
  border: 1px solid var(--sim-line);
  color: var(--text-dim);
  font-family: var(--font-mono);
  font-size: 11px;
  padding: 5px 10px;
  border-radius: 4px;
  cursor: pointer;
  transition: all 0.15s;
}

.preset-pill:hover {
  border-color: var(--sim-accent);
  color: var(--sim-accent);
}

.calc-result-box {
  display: flex;
  flex-direction: column;
  gap: 8px;
  background: #060B08;
  border: 1px solid var(--sim-line);
  border-radius: 6px;
  padding: 16px;
}

.result-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 13px;
  padding: 4px 0;
  border-bottom: 1px solid rgba(255,255,255,0.04);
}

.result-row:last-child {
  border-bottom: none;
}

.result-row .k {
  color: var(--text-dim);
}

.result-row .v {
  font-family: var(--font-mono);
  font-weight: 700;
  color: #FFF;
}

/* Ping Controls & Terminal */
.ping-controls {
  display: flex;
  gap: 14px;
  align-items: flex-end;
  flex-wrap: wrap;
}

.btn-arsenal-primary {
  background: var(--sim-accent);
  color: #03140A;
  font-family: var(--font-editorial);
  font-size: 13px;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.8px;
  padding: 0 20px;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  transition: all 0.2s;
}

.btn-arsenal-primary:hover {
  background: var(--sim-volt);
  box-shadow: 0 0 14px rgba(0, 230, 118, 0.4);
}

.terminal-screen {
  background: #030704;
  border: 1px solid var(--sim-line);
  border-radius: 6px;
  padding: 16px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: #A3E635;
  overflow-y: auto;
  line-height: 1.6;
}

.terminal-line.system {
  color: var(--text-dim);
}

.terminal-line.prompt {
  color: #FBBF24;
}

.terminal-line.success {
  color: #00FF87;
}

/* OSI Model Layout */
.osi-container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}

.osi-layers-stack {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.osi-layer-row {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 16px;
  background: var(--sim-panel);
  border: 1px solid var(--sim-line);
  border-radius: 6px;
  cursor: pointer;
  transition: all 0.2s;
}

.osi-layer-row:hover {
  background: var(--sim-panel-2);
  border-color: var(--sim-accent);
}

.osi-layer-row.active {
  background: var(--sim-panel-2);
  border-color: var(--sim-accent);
  box-shadow: inset 3px 0 0 var(--sim-accent);
}

.osi-layer-row .layer-num {
  font-family: var(--font-editorial);
  font-size: 16px;
  font-weight: 800;
  color: var(--sim-accent);
  width: 24px;
}

.osi-layer-row .layer-name {
  flex: 1;
  font-weight: 700;
  font-size: 13.5px;
  color: #FFF;
}

.osi-layer-row .layer-unit {
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--text-dim);
  background: rgba(255,255,255,0.06);
  padding: 2px 6px;
  border-radius: 3px;
}

.osi-details-panel {
  background: var(--sim-panel);
  border: 1px solid var(--sim-line);
  border-top: 3px solid var(--sim-accent);
  border-radius: 6px;
  padding: 24px;
}

.osi-info-box {
  font-size: 13px;
  color: var(--text-dim);
  line-height: 1.8;
}

.osi-info-box b {
  color: #FFF;
}

/* Toast Notification */
#hubToast {
  position: fixed;
  bottom: 24px;
  right: 24px;
  background: #0D1C13;
  border: 1px solid var(--sim-accent);
  color: #FFF;
  padding: 10px 18px;
  border-radius: 6px;
  font-size: 12.5px;
  font-weight: 700;
  box-shadow: 0 8px 24px rgba(0,0,0,0.8), 0 0 15px rgba(0,230,118,0.3);
  z-index: 1000;
  transform: translateY(120%);
  transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1);
  pointer-events: none;
}

#hubToast.show {
  transform: translateY(0);
}

@media (max-width: 900px) {
  .sim-fullscreen-frame {
    height: calc(100vh - 110px);
  }
  .sim-hub-topbar {
    padding: 8px 12px;
    gap: 10px;
  }
  .hub-tab-btn {
    font-size: 11px;
    padding: 6px 10px;
  }
  .osi-container {
    grid-template-columns: 1fr;
  }
}

/* ==========================================================================
   FULLSCREEN SIMULATOR MODE & FLOATING EXIT CONTROLS
   ========================================================================== */
body.is-fullscreen-sim .sim-hub-header {
  display: none !important;
}

body.is-fullscreen-sim .sim-fullscreen-frame {
  height: 100vh !important;
  min-height: 100vh !important;
}

body.is-fullscreen-sim .tool-tab-content {
  padding-top: 30px;
}

#exitFsFloatBtn {
  position: fixed;
  top: 14px;
  right: 14px;
  z-index: 99999;
  background: rgba(8, 17, 11, 0.92);
  border: 1.5px solid var(--sim-accent);
  color: #FFF;
  font-family: var(--font-display);
  font-size: 12px;
  font-weight: 700;
  padding: 8px 16px;
  border-radius: 30px;
  cursor: pointer;
  display: none;
  align-items: center;
  gap: 8px;
  box-shadow: 0 4px 24px rgba(0,0,0,0.85), 0 0 14px rgba(0,230,118,0.35);
  backdrop-filter: blur(10px);
  transition: all 0.2s ease;
}

#exitFsFloatBtn:hover {
  background: var(--sim-accent);
  color: #03140A;
  box-shadow: 0 0 20px rgba(0,230,118,0.6);
  transform: scale(1.03);
}

body.is-fullscreen-sim #exitFsFloatBtn {
  display: inline-flex;
  animation: fadeIn 0.3s ease;
}