:root {
  --bg-primary: #0f141c;
  --bg-secondary: #171f2d;
  --bg-panel: rgba(23, 31, 45, 0.85);
  --bg-input: #0b0f15;
  --border-color: #2b384e;
  --border-focus: #3b82f6;
  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --accent-blue: #38bdf8;
  --accent-cyan: #06b6d4;
  --accent-amber: #f59e0b;
  --accent-rose: #f43f5e;
  --accent-emerald: #10b981;
  --accent-purple: #a855f7;
  --bar-a-color: #38bdf8;
  --bar-b-color: #f43f5e;
  --axis-color: #f59e0b;
  --joint-color: #10b981;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body, html {
  width: 100%;
  height: 100%;
  overflow: hidden;
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  user-select: none;
}

#app-container {
  display: flex;
  flex-direction: column;
  width: 100vw;
  height: 100vh;
}

/* Header & Top Dashboard */
header {
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
  padding: 10px 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  z-index: 10;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
}

.brand h1 {
  font-size: 1.15rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  background: linear-gradient(135deg, #38bdf8, #818cf8);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.brand .badge {
  font-size: 0.7rem;
  font-weight: 600;
  padding: 2px 8px;
  border-radius: 9999px;
  background: rgba(56, 189, 248, 0.15);
  color: var(--accent-blue);
  border: 1px solid rgba(56, 189, 248, 0.3);
}

.top-dashboard {
  display: flex;
  align-items: center;
  gap: 12px;
}

.param-pill {
  display: flex;
  align-items: center;
  gap: 6px;
  background: rgba(11, 15, 21, 0.6);
  padding: 4px 10px;
  border-radius: 6px;
  border: 1px solid var(--border-color);
  font-family: var(--font-mono);
  font-size: 0.78rem;
}

.param-pill .label {
  color: var(--text-secondary);
}

.param-pill .val {
  font-weight: 700;
  color: var(--accent-cyan);
}

.status-pill {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.78rem;
  font-weight: 600;
  padding: 4px 10px;
  border-radius: 6px;
  background: rgba(16, 185, 129, 0.12);
  color: var(--accent-emerald);
  border: 1px solid rgba(16, 185, 129, 0.3);
  transition: all 0.2s ease;
}

.status-pill.paused {
  background: rgba(245, 158, 11, 0.12);
  color: var(--accent-amber);
  border-color: rgba(245, 158, 11, 0.3);
}

.status-pill .indicator-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: currentColor;
  box-shadow: 0 0 8px currentColor;
}

/* Main Workspace */
#workspace {
  flex: 1;
  display: flex;
  position: relative;
  overflow: hidden;
}

/* Canvas Area */
#canvas-container {
  flex: 1;
  position: relative;
  background-color: var(--bg-primary);
  background-image: 
    radial-gradient(circle at 1px 1px, rgba(255, 255, 255, 0.04) 1px, transparent 0);
  background-size: 24px 24px;
}

canvas {
  width: 100%;
  height: 100%;
  display: block;
  cursor: default;
}

/* On-Canvas Floating Alerts/Guides */
.canvas-floating-hud {
  position: absolute;
  top: 14px;
  left: 20px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  pointer-events: none;
  z-index: 5;
}

.hud-notice {
  background: rgba(15, 20, 28, 0.85);
  backdrop-filter: blur(8px);
  border: 1px solid var(--border-color);
  padding: 6px 12px;
  border-radius: 6px;
  font-size: 0.78rem;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  gap: 8px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.4);
}

.hud-notice .icon {
  font-size: 0.9rem;
}

.hud-alert-auto-pause {
  background: rgba(244, 63, 94, 0.15);
  border: 1px solid rgba(244, 63, 94, 0.4);
  color: #fda4af;
  padding: 6px 12px;
  border-radius: 6px;
  font-size: 0.8rem;
  font-weight: 600;
  display: none;
  animation: fadeInOut 2s ease forwards;
}

@keyframes fadeInOut {
  0% { opacity: 0; transform: translateY(-4px); }
  15% { opacity: 1; transform: translateY(0); }
  85% { opacity: 1; transform: translateY(0); }
  100% { opacity: 0; transform: translateY(-4px); }
}

.canvas-controls-overlay {
  position: absolute;
  bottom: 16px;
  left: 20px;
  display: flex;
  gap: 8px;
  z-index: 5;
}

.mini-tool-btn {
  background: rgba(23, 31, 45, 0.85);
  backdrop-filter: blur(8px);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  padding: 6px 10px;
  border-radius: 6px;
  font-size: 0.75rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 6px;
  transition: all 0.15s ease;
}

.mini-tool-btn:hover {
  background: var(--bg-secondary);
  color: var(--text-primary);
  border-color: var(--text-muted);
}

/* Sidebar / Control Panel */
#sidebar {
  width: 360px;
  background: var(--bg-panel);
  backdrop-filter: blur(12px);
  border-left: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  z-index: 10;
  box-shadow: -4px 0 16px rgba(0, 0, 0, 0.4);
  overflow-y: auto;
}

.panel-section {
  padding: 16px 18px;
  border-bottom: 1px solid rgba(43, 56, 78, 0.6);
}

.section-title {
  font-size: 0.85rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-secondary);
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.section-title .badge-num {
  font-size: 0.68rem;
  background: rgba(56, 189, 248, 0.15);
  color: var(--accent-blue);
  padding: 2px 6px;
  border-radius: 4px;
}

/* Form Controls & Inputs */
.input-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}

.input-group {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.input-group.full-width {
  grid-column: span 2;
}

.input-label-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

label {
  font-size: 0.78rem;
  color: var(--text-secondary);
  font-weight: 500;
}

.input-hint {
  font-size: 0.7rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
}

input[type="number"], select {
  background: var(--bg-input);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  font-family: var(--font-mono);
  font-size: 0.85rem;
  padding: 7px 10px;
  border-radius: 6px;
  outline: none;
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
  width: 100%;
}

input[type="number"]:focus, select:focus {
  border-color: var(--border-focus);
  box-shadow: 0 0 0 2px rgba(59, 130, 246, 0.25);
}

.color-indicator {
  display: inline-block;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  margin-right: 4px;
}

/* Action Buttons */
.btn-group {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-top: 12px;
}

.btn-row {
  display: flex;
  gap: 8px;
}

button {
  cursor: pointer;
  border: none;
  border-radius: 6px;
  font-weight: 600;
  font-size: 0.82rem;
  padding: 8px 14px;
  transition: all 0.15s ease;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
}

.btn-primary {
  background: linear-gradient(135deg, #0284c7, #2563eb);
  color: #fff;
  box-shadow: 0 2px 8px rgba(37, 99, 235, 0.3);
}

.btn-primary:hover {
  background: linear-gradient(135deg, #0369a1, #1d4ed8);
  box-shadow: 0 4px 12px rgba(37, 99, 235, 0.4);
}

.btn-accent {
  background: linear-gradient(135deg, #059669, #10b981);
  color: #fff;
  box-shadow: 0 2px 8px rgba(16, 185, 129, 0.3);
}

.btn-accent:hover {
  background: linear-gradient(135deg, #047857, #059669);
}

.btn-accent.stop {
  background: linear-gradient(135deg, #e11d48, #f43f5e);
  box-shadow: 0 2px 8px rgba(244, 63, 94, 0.3);
}

.btn-secondary {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
}

.btn-secondary:hover {
  background: rgba(43, 56, 78, 0.8);
  border-color: var(--text-muted);
}

.btn-danger {
  background: rgba(244, 63, 94, 0.15);
  border: 1px solid rgba(244, 63, 94, 0.3);
  color: #fda4af;
}

.btn-danger:hover {
  background: rgba(244, 63, 94, 0.25);
  border-color: rgba(244, 63, 94, 0.5);
}

/* Checkbox Toggle */
.toggle-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 6px 0;
}

.toggle-label {
  font-size: 0.8rem;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  gap: 8px;
}

input[type="checkbox"] {
  width: 16px;
  height: 16px;
  accent-color: var(--accent-blue);
  cursor: pointer;
}

/* Legend & Color Guide */
.legend-list {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-top: 6px;
  font-size: 0.76rem;
}

.legend-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 4px 8px;
  border-radius: 4px;
  background: rgba(11, 15, 21, 0.4);
}

.legend-color-sample {
  display: flex;
  align-items: center;
  gap: 8px;
}

.color-bar-thick {
  width: 24px;
  height: 6px;
  border-radius: 3px;
  background: var(--bar-a-color);
}

.color-bar-thin {
  width: 24px;
  height: 2px;
  border-radius: 1px;
  background: var(--bar-b-color);
}

.color-dot-axis {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--axis-color);
  border: 2px solid #fff;
}

.color-dot-joint {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--joint-color);
  box-shadow: 0 0 6px var(--joint-color);
}

.color-dot-q {
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--accent-purple);
  box-shadow: 0 0 8px var(--accent-purple);
}

/* Guide Accordion */
.guide-content {
  font-size: 0.77rem;
  line-height: 1.5;
  color: var(--text-secondary);
  display: flex;
  flex-direction: column;
  gap: 8px;
  background: rgba(11, 15, 21, 0.4);
  padding: 10px;
  border-radius: 6px;
  border: 1px solid rgba(43, 56, 78, 0.4);
}

.guide-step {
  display: flex;
  align-items: flex-start;
  gap: 8px;
}

.guide-step .step-idx {
  font-weight: 700;
  color: var(--accent-cyan);
  font-family: var(--font-mono);
}

/* Scrollbar */
#sidebar::-webkit-scrollbar {
  width: 6px;
}
#sidebar::-webkit-scrollbar-track {
  background: transparent;
}
#sidebar::-webkit-scrollbar-thumb {
  background: rgba(255, 255, 255, 0.1);
  border-radius: 3px;
}
#sidebar::-webkit-scrollbar-thumb:hover {
  background: rgba(255, 255, 255, 0.2);
}