/* ==========================================================================
   Conservation of Linear Momentum - Virtual Physics Laboratory Styling
   ========================================================================== */

:root {
  /* Color Palette - University Technical Theme */
  --bg-main: #f8fafc;
  --bg-card: #ffffff;
  --bg-sidebar: #f1f5f9;
  
  --text-main: #0f172a;
  --text-muted: #64748b;
  --text-inverse: #ffffff;

  --border-color: #e2e8f0;
  --border-focus: #3b82f6;

  /* Primary Brand Colors */
  --primary-blue: #1e40af;
  --primary-hover: #1d4ed8;
  --primary-light: #eff6ff;

  /* Object 1 Theme (Blue/Teal) */
  --obj1-color: #2563eb;
  --obj1-light: #dbeafe;
  --obj1-dark: #1e3a8a;
  --obj1-gradient: linear-gradient(135deg, #3b82f6 0%, #1d4ed8 100%);

  /* Object 2 Theme (Amber/Coral) */
  --obj2-color: #d97706;
  --obj2-light: #fef3c7;
  --obj2-dark: #78350f;
  --obj2-gradient: linear-gradient(135deg, #f59e0b 0%, #d97706 100%);

  /* UI Status Colors */
  --accent-green: #10b981;
  --accent-green-bg: #ecfdf5;
  --accent-red: #ef4444;
  --accent-purple: #8b5cf6;

  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(15, 23, 42, 0.08);
  --shadow-md: 0 4px 12px rgba(15, 23, 42, 0.08);
  --shadow-lg: 0 10px 25px rgba(15, 23, 42, 0.12);

  /* Fonts */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', monospace;
}

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-main);
  color: var(--text-main);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

/* Lab Header */
.lab-header {
  background: #ffffff;
  border-bottom: 1px solid var(--border-color);
  padding: 1.25rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
  box-shadow: var(--shadow-sm);
}

.lab-title-area {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.lab-badge {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--primary-blue);
  background: var(--primary-light);
  padding: 0.2rem 0.6rem;
  border-radius: 4px;
  width: fit-content;
}

.lab-header h1 {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--text-main);
  letter-spacing: -0.02em;
}

.lab-subtitle {
  font-size: 0.9rem;
  color: var(--text-muted);
  font-weight: 500;
}

/* Mode Selector Pills */
.mode-selector {
  display: flex;
  background: #f1f5f9;
  padding: 4px;
  border-radius: 8px;
  border: 1px solid var(--border-color);
}

.mode-btn {
  background: transparent;
  border: none;
  padding: 0.5rem 1rem;
  font-family: var(--font-sans);
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--text-muted);
  border-radius: 6px;
  cursor: pointer;
  transition: all 0.2s ease;
}

.mode-btn.active {
  background: #ffffff;
  color: var(--primary-blue);
  box-shadow: var(--shadow-sm);
}

/* Main Layout Grid */
.lab-main {
  max-width: 1400px;
  margin: 1.5rem auto;
  padding: 0 1.5rem;
}

.lab-grid {
  display: grid;
  grid-template-columns: 1fr 360px;
  gap: 1.5rem;
}

.full-width-card {
  grid-column: 1 / -1;
}

/* Cards System */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 1.25rem;
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.card-header {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  border-bottom: 1px solid #f1f5f9;
  padding-bottom: 0.75rem;
}

.flex-between {
  justify-content: space-between;
}

.title-with-icon {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.card-header h2 {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-main);
}

.card-header svg {
  color: var(--primary-blue);
}

/* Collision Type Toggle */
.collision-type-toggle {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.label-text {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-muted);
}

.toggle-group {
  display: flex;
  background: #f1f5f9;
  padding: 3px;
  border-radius: 8px;
  border: 1px solid var(--border-color);
}

.toggle-btn {
  background: transparent;
  border: none;
  padding: 0.4rem 0.8rem;
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--text-muted);
  border-radius: 5px;
  cursor: pointer;
  transition: all 0.2s ease;
}

.toggle-btn.active {
  background: var(--primary-blue);
  color: #ffffff;
  box-shadow: var(--shadow-sm);
}

/* Hero Canvas Container */
.sim-container {
  position: relative;
  width: 100%;
  height: 380px;
  background: linear-gradient(180deg, #f8fafc 0%, #e2e8f0 100%);
  border: 1px solid var(--border-color);
  border-radius: 10px;
  overflow: hidden;
}

#simCanvas {
  width: 100%;
  height: 100%;
  display: block;
}

/* Verification Badge Overlay */
.verification-badge {
  position: absolute;
  top: 16px;
  right: 16px;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  background: rgba(16, 185, 129, 0.95);
  color: #ffffff;
  padding: 0.6rem 1rem;
  border-radius: 8px;
  box-shadow: var(--shadow-md);
  backdrop-filter: blur(4px);
  border: 1px solid rgba(255, 255, 255, 0.3);
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  transform: translateY(0);
  opacity: 1;
}

.verification-badge.hidden {
  opacity: 0;
  transform: translateY(-10px);
  pointer-events: none;
}

.badge-icon {
  font-size: 1.25rem;
  font-weight: 900;
  line-height: 1;
}

.badge-content {
  display: flex;
  flex-direction: column;
}

.badge-title {
  font-size: 0.85rem;
  font-weight: 800;
  letter-spacing: 0.05em;
}

.badge-sub {
  font-size: 0.75rem;
  font-family: var(--font-mono);
  opacity: 0.9;
}

/* Controls Bar */
.sim-controls-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
  background: #f8fafc;
  padding: 0.75rem 1rem;
  border-radius: 8px;
  border: 1px solid var(--border-color);
}

.btn-group {
  display: flex;
  gap: 0.5rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.6rem 1.25rem;
  font-family: var(--font-sans);
  font-size: 0.85rem;
  font-weight: 700;
  border-radius: 6px;
  border: none;
  cursor: pointer;
  transition: all 0.15s ease;
}

.btn-primary {
  background: var(--primary-blue);
  color: #ffffff;
}

.btn-primary:hover {
  background: var(--primary-hover);
  box-shadow: 0 4px 8px rgba(37, 99, 235, 0.3);
}

.btn-secondary {
  background: #ffffff;
  color: var(--text-main);
  border: 1px solid var(--border-color);
}

.btn-secondary:hover {
  background: #f1f5f9;
  border-color: #cbd5e1;
}

.btn-accent {
  background: #059669;
  color: #ffffff;
}

.btn-accent:hover {
  background: #047857;
  box-shadow: 0 4px 8px rgba(16, 185, 129, 0.3);
}

.btn-danger {
  background: #fee2e2;
  color: #b91c1c;
  border: 1px solid #fca5a5;
}

.btn-danger:hover {
  background: #fecaca;
}

.btn-sm {
  padding: 0.4rem 0.8rem;
  font-size: 0.78rem;
}

/* Speed Controls */
.speed-control {
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.speed-label {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-muted);
}

.speed-btn {
  background: #ffffff;
  border: 1px solid var(--border-color);
  padding: 0.3rem 0.6rem;
  font-size: 0.75rem;
  font-family: var(--font-mono);
  font-weight: 700;
  color: var(--text-muted);
  border-radius: 4px;
  cursor: pointer;
}

.speed-btn.active {
  background: var(--primary-blue);
  color: #ffffff;
  border-color: var(--primary-blue);
}

/* Presets Bar */
.presets-bar {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-wrap: wrap;
  padding-top: 0.25rem;
}

.preset-title {
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--text-muted);
}

.preset-buttons {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.preset-chip {
  background: #f1f5f9;
  border: 1px solid var(--border-color);
  color: var(--text-main);
  font-size: 0.75rem;
  font-weight: 600;
  padding: 0.3rem 0.7rem;
  border-radius: 16px;
  cursor: pointer;
  transition: all 0.15s ease;
}

.preset-chip:hover {
  background: var(--primary-light);
  border-color: var(--primary-blue);
  color: var(--primary-blue);
}

/* Controls Sidebar */
.sidebar-card {
  background: var(--bg-card);
}

.controls-wrapper {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.object-control-block {
  padding: 1rem;
  border-radius: 8px;
  border: 1px solid var(--border-color);
  background: #fafafa;
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}

.object1-theme {
  border-left: 4px solid var(--obj1-color);
  background: linear-gradient(180deg, #f0f7ff 0%, #fafafa 100%);
}

.object2-theme {
  border-left: 4px solid var(--obj2-color);
  background: linear-gradient(180deg, #fffbeb 0%, #fafafa 100%);
}

.block-header {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.obj-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
}

.obj1-dot { background: var(--obj1-color); }
.obj2-dot { background: var(--obj2-color); }

.block-header h3 {
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--text-main);
}

.control-group {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

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

.control-label-row label {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-main);
}

.input-with-unit {
  display: flex;
  align-items: center;
  gap: 0.2rem;
  background: #ffffff;
  border: 1px solid var(--border-color);
  padding: 0.15rem 0.4rem;
  border-radius: 4px;
}

.input-with-unit input {
  width: 55px;
  border: none;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--text-main);
  text-align: right;
  outline: none;
}

.input-with-unit .unit {
  font-size: 0.75rem;
  color: var(--text-muted);
  font-weight: 600;
}

/* Custom Range Sliders */
input[type=range] {
  -webkit-appearance: none;
  width: 100%;
  background: transparent;
}

input[type=range]:focus {
  outline: none;
}

input[type=range]::-webkit-slider-runnable-track {
  width: 100%;
  height: 6px;
  cursor: pointer;
  background: #cbd5e1;
  border-radius: 3px;
}

input[type=range]::-webkit-slider-thumb {
  height: 18px;
  width: 18px;
  border-radius: 50%;
  background: #ffffff;
  border: 2px solid var(--primary-blue);
  cursor: pointer;
  -webkit-appearance: none;
  margin-top: -6px;
  box-shadow: var(--shadow-sm);
  transition: transform 0.1s ease;
}

.object1-theme input[type=range]::-webkit-slider-thumb { border-color: var(--obj1-color); }
.object2-theme input[type=range]::-webkit-slider-thumb { border-color: var(--obj2-color); }

input[type=range]::-webkit-slider-thumb:hover {
  transform: scale(1.15);
}

.slider-ticks {
  display: flex;
  justify-content: space-between;
  font-size: 0.68rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
}

/* Analytics Diagnostics Grid */
.diagnostics-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1rem;
}

.diag-block {
  background: #f8fafc;
  border: 1px solid var(--border-color);
  padding: 0.85rem 1rem;
  border-radius: 8px;
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
}

.diag-subtitle {
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
}

.readout-metrics {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.metric-box {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.4rem 0.65rem;
  background: #ffffff;
  border-radius: 6px;
  border: 1px solid var(--border-color);
}

.obj1-border { border-left: 3px solid var(--obj1-color); }
.obj2-border { border-left: 3px solid var(--obj2-color); }
.total-border { border-left: 3px solid var(--primary-blue); background: var(--primary-light); }

.metric-label {
  font-size: 0.8rem;
  font-family: var(--font-mono);
  font-weight: 600;
  color: var(--text-main);
}

.metric-val {
  font-size: 0.88rem;
  font-family: var(--font-mono);
  font-weight: 700;
  color: var(--text-main);
}

.highlight-val {
  color: var(--primary-blue);
}

/* KE Block */
.ke-block {
  background: #fdf4ff;
  border-color: #f5d0fe;
}

.ke-block .diag-subtitle {
  color: var(--accent-purple);
}

.ke-readout-row {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
}

.ke-item {
  display: flex;
  justify-content: space-between;
  font-size: 0.82rem;
}

.ke-label {
  font-weight: 600;
  color: #4c1d95;
}

.ke-val {
  font-family: var(--font-mono);
  font-weight: 700;
  color: #581c87;
}

.ke-note {
  font-size: 0.73rem;
  color: #6b21a8;
  font-style: italic;
}

/* Visual Momentum Bars Section */
.momentum-bar-section {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  background: #f1f5f9;
  padding: 1rem;
  border-radius: 8px;
  border: 1px solid var(--border-color);
}

.bar-section-title {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.82rem;
  font-weight: 700;
  color: var(--text-main);
}

.dir-indicator {
  font-size: 0.75rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
}

.bar-container {
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}

.bar-row {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.bar-row-label {
  width: 60px;
  font-size: 0.75rem;
  font-weight: 800;
  color: var(--text-muted);
}

.bar-track {
  position: relative;
  flex: 1;
  height: 28px;
  background: #ffffff;
  border-radius: 6px;
  border: 1px solid var(--border-color);
  overflow: hidden;
}

.zero-axis {
  position: absolute;
  left: 50%;
  top: 0;
  bottom: 0;
  width: 2px;
  background: #94a3b8;
  z-index: 2;
}

.bar-fill {
  position: absolute;
  top: 3px;
  bottom: 3px;
  height: calc(100% - 6px);
  border-radius: 4px;
  display: flex;
  align-items: center;
  padding: 0 0.5rem;
  transition: all 0.3s ease;
  z-index: 1;
}

.before-bar {
  background: var(--obj1-gradient);
}

.after-bar {
  background: linear-gradient(135deg, #10b981 0%, #059669 100%);
}

.bar-text {
  font-size: 0.72rem;
  font-family: var(--font-mono);
  font-weight: 700;
  color: #ffffff;
  white-space: nowrap;
  text-shadow: 0 1px 2px rgba(0,0,0,0.4);
}

/* Graph Canvas Card */
.graph-tab-toggle {
  display: flex;
  background: #f1f5f9;
  padding: 3px;
  border-radius: 6px;
}

.tab-btn {
  background: transparent;
  border: none;
  padding: 0.3rem 0.7rem;
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--text-muted);
  border-radius: 4px;
  cursor: pointer;
}

.tab-btn.active {
  background: #ffffff;
  color: var(--primary-blue);
  box-shadow: var(--shadow-sm);
}

.graph-container {
  position: relative;
  width: 100%;
  height: 260px;
  background: #0f172a;
  border-radius: 8px;
  overflow: hidden;
  border: 1px solid var(--border-color);
}

#graphCanvas {
  width: 100%;
  height: 100%;
  display: block;
}

.graph-legend {
  position: absolute;
  top: 10px;
  right: 15px;
  display: flex;
  gap: 1rem;
  background: rgba(15, 23, 42, 0.85);
  padding: 0.35rem 0.75rem;
  border-radius: 6px;
  border: 1px solid rgba(255, 255, 255, 0.15);
}

.legend-item {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  font-size: 0.72rem;
  color: #cbd5e1;
  font-family: var(--font-mono);
}

.legend-color {
  width: 10px;
  height: 10px;
  border-radius: 2px;
}

.legend-p1 { background: #3b82f6; }
.legend-p2 { background: #f59e0b; }
.legend-total { background: #10b981; }

/* Table Section */
.table-responsive {
  overflow-x: auto;
  border: 1px solid var(--border-color);
  border-radius: 8px;
}

.obs-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.8rem;
  text-align: center;
}

.obs-table th {
  background: #f1f5f9;
  color: var(--text-main);
  font-weight: 700;
  padding: 0.6rem 0.75rem;
  border-bottom: 2px solid var(--border-color);
  white-space: nowrap;
}

.obs-table td {
  padding: 0.55rem 0.75rem;
  border-bottom: 1px solid var(--border-color);
  font-family: var(--font-mono);
  white-space: nowrap;
}

.obs-table tbody tr:nth-child(even) {
  background: #f8fafc;
}

.obs-table tbody tr:hover {
  background: var(--primary-light);
}

.empty-row td {
  color: var(--text-muted);
  font-family: var(--font-sans);
  font-style: italic;
  padding: 1.5rem;
}

/* Theory Card */
.theory-card {
  background: #ffffff;
}

.theory-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.25rem;
}

.theory-block {
  background: #f8fafc;
  border: 1px solid var(--border-color);
  padding: 1rem;
  border-radius: 8px;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.theory-block h3 {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--primary-blue);
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 0.35rem;
}

.theory-block p {
  font-size: 0.83rem;
  color: #334155;
  line-height: 1.6;
}

.theory-block ul {
  padding-left: 1.25rem;
  font-size: 0.83rem;
  color: #334155;
}

.theory-block li {
  margin-bottom: 0.4rem;
}

.formula-box {
  background: #ffffff;
  border: 1px solid var(--border-color);
  padding: 0.5rem;
  border-radius: 6px;
  text-align: center;
  font-family: var(--font-mono);
  font-weight: 700;
  color: var(--primary-blue);
  font-size: 0.9rem;
  box-shadow: var(--shadow-sm);
}

.formula-box-sm {
  background: #ffffff;
  border: 1px solid var(--border-color);
  padding: 0.4rem;
  border-radius: 4px;
  font-family: var(--font-mono);
  font-size: 0.74rem;
  color: var(--text-main);
  margin-top: 0.3rem;
}

/* Footer */
.lab-footer {
  text-align: center;
  padding: 1.5rem;
  color: var(--text-muted);
  font-size: 0.8rem;
  border-top: 1px solid var(--border-color);
  background: #ffffff;
  margin-top: 2rem;
}

/* Responsive Media Queries */
@media (max-width: 1024px) {
  .lab-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 640px) {
  .lab-header {
    flex-direction: column;
    align-items: flex-start;
  }
  
  .sim-container {
    height: 300px;
  }

  .sim-controls-bar {
    flex-direction: column;
    align-items: stretch;
  }

  .btn-group {
    flex-direction: column;
  }

  .preset-buttons {
    flex-direction: column;
  }
}