/* ===== CSS Custom Properties (matched to bits-and-electrons/bloch-sphere-simulator) ===== */
:root {
  --bg-primary: #0d1117;
  --bg-secondary: #161b22;
  --bg-tertiary: #1c2333;
  --bg-surface: rgba(22, 27, 34, 0.85);
  --border-color: rgba(255, 255, 255, 0.08);
  --border-hover: rgba(255, 255, 255, 0.15);
  --text-primary: #e6edf3;
  --text-secondary: #8b949e;
  --text-muted: #6e7681;
  --accent: #58a6ff;
  --accent-hover: #79bbff;
  --accent-active: #388bfd;
  --accent-glow: rgba(88, 166, 255, 0.15);
  --danger: #f85149;
  --warning: #d29922;
  --success: #3fb950;
  --info: #58a6ff;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.5);
  --transition: 0.2s ease;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, sans-serif;
  --font-mono: 'JetBrains Mono', 'SF Mono', 'Fira Code', 'Cascadia Code', monospace;
  --navbar-height: 56px;
}

/* ===== Base ===== */
html, body {
  font-family: var(--font-sans);
  color: var(--text-primary);
  background-color: var(--bg-primary);
  height: 100%;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  margin: 0;
}

body {
  padding-top: var(--navbar-height);
}

*, *::before, *::after {
  box-sizing: border-box;
}

button {
  font-family: inherit;
  cursor: pointer;
}

/* ===== Navbar ===== */
.navbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--navbar-height);
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--bg-surface);
  backdrop-filter: blur(16px) saturate(180%);
  -webkit-backdrop-filter: blur(16px) saturate(180%);
  border-bottom: 1px solid var(--border-color);
  padding: 0.5rem 1.25rem;
  z-index: 1030;
}

.navbar-brand {
  font-weight: 700;
  font-size: 1.1rem;
  letter-spacing: -0.01em;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.brand-icon {
  width: 28px;
  height: 28px;
  border-radius: var(--radius-sm);
  display: block;
}

.navbar-controls {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.btn-nav {
  background: transparent;
  border: none;
  color: var(--text-secondary);
  font-size: 0.8rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 0.4rem 0.75rem;
  border-radius: var(--radius-sm);
  text-decoration: none;
  display: inline-block;
  transition: color var(--transition), background var(--transition);
}

.btn-nav:hover {
  color: var(--text-primary);
  background: rgba(255, 255, 255, 0.06);
}

.version-badge {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--text-secondary);
  padding: 0.4rem 0.5rem;
  border-radius: var(--radius-sm);
  text-decoration: none;
  display: inline-block;
  transition: color var(--transition), background var(--transition);
}

.version-badge:hover {
  color: var(--text-primary);
  background: rgba(255, 255, 255, 0.06);
}

.qubit-stepper {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-secondary);
  padding: 0 0.5rem;
  border-right: 1px solid var(--border-color);
  margin-right: 0.25rem;
}

.stepper-label {
  text-transform: uppercase;
  letter-spacing: 0.05em;
  font-family: var(--font-sans);
  font-size: 0.75rem;
}

.btn-stepper {
  padding: 0.15rem 0.55rem;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  border: 1px solid var(--border-color);
}

#qubit-count {
  min-width: 1.2rem;
  text-align: center;
  color: var(--accent);
  font-weight: 600;
}

.shots-control {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-secondary);
  padding: 0 0.5rem;
  border-right: 1px solid var(--border-color);
  margin-right: 0.25rem;
}

.shots-input {
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-family: var(--font-mono);
  font-size: 0.8rem;
  padding: 0.2rem 0.4rem;
  width: 5.5rem;
}

.shots-input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-glow);
}

.dropdown {
  position: relative;
}

.dropdown-menu {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  min-width: 190px;
  padding: 0.35rem;
  z-index: 1040;
}

.dropdown-item {
  padding: 0.5rem 0.7rem;
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  color: var(--text-primary);
  transition: background var(--transition);
  cursor: pointer;
}

.dropdown-item:hover {
  background: rgba(88, 166, 255, 0.12);
  color: var(--accent);
}

/* ===== App Shell ===== */
.app-shell {
  display: flex;
  height: calc(100vh - var(--navbar-height));
}

.main-col {
  flex: 1 1 auto;
  display: flex;
  flex-direction: column;
  min-width: 0;
}

#toolbox {
  width: 25vw;
  flex: 0 0 auto;
  overflow-y: auto;
  background: var(--bg-secondary);
  border-left: 1px solid var(--border-color);
  scrollbar-width: thin;
  scrollbar-color: var(--border-hover) transparent;
}

#toolbox::-webkit-scrollbar { width: 6px; }
#toolbox::-webkit-scrollbar-track { background: transparent; }
#toolbox::-webkit-scrollbar-thumb { background: var(--border-hover); border-radius: 3px; }

.toolbox-inner { padding: 1.25rem 1rem 2rem; }

.toolbox-header h4 {
  font-weight: 700;
  font-size: 1.2rem;
  letter-spacing: -0.01em;
  text-align: center;
  margin: 0 0 1.25rem;
  color: var(--text-primary);
  position: relative;
}

.toolbox-header h4::after {
  content: '';
  display: block;
  width: 40px;
  height: 2px;
  background: var(--accent);
  margin: 0.5rem auto 0;
  border-radius: 1px;
}

.gate-category { margin-bottom: 1.75rem; }
.gate-category:last-child { margin-bottom: 0; }

.gate-category-title {
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-primary);
  margin-bottom: 0.9rem;
  padding-bottom: 0.4rem;
  border-bottom: 2px solid var(--accent);
}

.gate-subsection { margin-bottom: 0.85rem; }
.gate-subsection:last-child { margin-bottom: 0; }

.gate-subsection-title {
  font-size: 0.68rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-secondary);
  margin-bottom: 0.45rem;
}

.gate-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.gate-row {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.quantum-gate.btn-custom {
  min-width: 56px;
  text-align: center;
  border-radius: var(--radius-sm);
  font-size: 0.8rem;
  padding: 0.5rem 0.7rem;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  transition: all var(--transition);
}

.quantum-gate.btn-custom:hover {
  background: rgba(88, 166, 255, 0.12);
  border-color: var(--accent);
  color: var(--accent);
  box-shadow: 0 0 12px var(--accent-glow);
}

.quantum-gate.btn-custom:active {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

.form-control {
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-size: 0.85rem;
  padding: 0.45rem 0.6rem;
  width: 100%;
  font-family: var(--font-mono);
}

.form-control:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-glow);
}

/* ===== Circuit Panel ===== */
.circuit-panel {
  flex: 1 1 auto;
  min-height: 0;
  display: flex;
  flex-direction: column;
  padding: 1.25rem 1.5rem 0.75rem;
  overflow: hidden;
}

.panel-header {
  display: flex;
  align-items: baseline;
  gap: 0.75rem;
  margin-bottom: 0.75rem;
  flex-wrap: wrap;
}

.panel-title {
  font-weight: 700;
  font-size: 1rem;
  letter-spacing: -0.01em;
}

.panel-hint {
  font-size: 0.75rem;
  color: var(--text-muted);
}

.circuit-body {
  flex: 1 1 auto;
  min-height: 0;
  display: flex;
  flex-direction: row;
  gap: 0.75rem;
}

.circuit-scroll {
  flex: 1 1 auto;
  min-width: 0;
  min-height: 0;
  overflow: auto;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1rem 1.25rem;
}

.circuit-grid-inner {
  position: relative;
  display: grid;
  width: 100%;
  height: 100%;
}

.connector-layer {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 1;
}

.qubit-label {
  display: flex;
  align-items: center;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.wire-line {
  align-self: center;
  width: 100%;
  height: 2px;
  background: var(--border-hover);
  z-index: 0;
}

.cell {
  position: relative;
  z-index: 2;
  transition: background var(--transition);
  border-radius: var(--radius-sm);
}

.cell.drag-over {
  background: rgba(88, 166, 255, 0.1);
}

.cell.link-target {
  background: var(--accent-glow);
  outline: 2px dashed var(--accent);
  outline-offset: -2px;
  cursor: pointer;
}

.cell.link-source {
  outline: 2px solid var(--accent);
  outline-offset: -2px;
  border-radius: 50%;
}

/* ===== Gate Chips ===== */
.gate-chip {
  position: absolute;
  inset: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 0.8rem;
  cursor: pointer;
  user-select: none;
  transition: box-shadow var(--transition), border-color var(--transition);
}

.gate-single, .gate-rotation, .gate-measure {
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
}

.gate-single:hover, .gate-rotation:hover, .gate-measure:hover {
  border-color: var(--accent);
  box-shadow: 0 0 10px var(--accent-glow);
}

.gate-rotation {
  color: var(--accent);
  border-color: rgba(88, 166, 255, 0.3);
}

.gate-measure {
  color: var(--warning);
  border-color: rgba(210, 153, 34, 0.3);
}

.gate-random {
  color: var(--success);
  border-color: rgba(63, 185, 80, 0.3);
}

.gate-snapshot {
  background: var(--bg-tertiary);
  border: 1px solid rgba(255, 209, 102, 0.35);
  padding: 3px;
}

.gate-snapshot:hover {
  border-color: #ffd166;
  box-shadow: 0 0 10px rgba(255, 209, 102, 0.25);
}

.gate-snapshot-sphere {
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #ffd166;
  font-size: 0.9rem;
  line-height: 1;
}

.gate-snapshot-sphere svg {
  width: 100%;
  height: 100%;
  display: block;
}

.gate-control {
  inset: auto;
  width: 14px;
  height: 14px;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 8px var(--accent-glow);
}

.gate-dot {
  inset: auto;
  width: 14px;
  height: 14px;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 8px var(--accent-glow);
}

.gate-target {
  inset: auto;
  width: 26px;
  height: 26px;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
  border-radius: 50%;
  border: 2px solid var(--accent);
  background: var(--bg-secondary);
}

.gate-target::before, .gate-target::after {
  content: '';
  position: absolute;
  background: var(--accent);
}

.gate-target::before {
  width: 2px;
  height: 16px;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
}

.gate-target::after {
  width: 16px;
  height: 2px;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
}

.gate-swap-x {
  inset: auto;
  width: 22px;
  height: 22px;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
}

.gate-swap-x::before, .gate-swap-x::after {
  content: '';
  position: absolute;
  width: 2px;
  height: 22px;
  background: var(--accent);
  left: 50%;
  top: 50%;
}

.gate-swap-x::before { transform: translate(-50%, -50%) rotate(45deg); }
.gate-swap-x::after { transform: translate(-50%, -50%) rotate(-45deg); }

.gate-delete {
  position: absolute;
  top: -6px;
  right: -6px;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--danger);
  color: #fff;
  font-size: 11px;
  line-height: 16px;
  text-align: center;
  opacity: 0;
  transition: opacity var(--transition), transform var(--transition);
  z-index: 3;
}

.cell:hover .gate-delete {
  opacity: 1;
}

.gate-delete:hover {
  transform: scale(1.15);
}

/* ===== Angle Popover ===== */
.angle-popover {
  position: absolute;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  padding: 0.9rem 1rem;
  width: 220px;
  z-index: 1050;
}

.angle-popover-title {
  font-size: 0.8rem;
  color: var(--text-secondary);
  margin-bottom: 0.6rem;
  font-weight: 500;
}

.angle-value {
  margin-top: 0.5rem;
  font-family: var(--font-mono);
  color: var(--accent);
  font-size: 0.85rem;
  font-weight: 600;
  text-align: center;
}

.custom-range {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 4px;
  background: var(--bg-tertiary);
  border-radius: 2px;
  outline: none;
}

.custom-range::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 16px;
  height: 16px;
  background: var(--accent);
  border-radius: 50%;
  cursor: pointer;
}

.custom-range::-moz-range-thumb {
  width: 16px;
  height: 16px;
  background: var(--accent);
  border: none;
  border-radius: 50%;
  cursor: pointer;
}

/* ===== Results Panel ===== */
.results-panel {
  flex: 0 0 25vh;
  height: 25vh;
  overflow-y: auto;
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  padding: 1rem 1.5rem 1.5rem;
  scrollbar-width: thin;
  scrollbar-color: var(--border-hover) transparent;
}

.results-summary {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 1rem;
}

.results-section {
  margin-bottom: 1.5rem;
}

.results-section-title {
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-primary);
  margin-bottom: 0.6rem;
  position: relative;
  padding-left: 0.6rem;
}

.results-section-title::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0.15rem;
  bottom: 0.15rem;
  width: 3px;
  background: var(--accent);
  border-radius: 2px;
}

.results-note {
  font-size: 0.7rem;
  color: var(--text-muted);
  margin-top: 0.4rem;
}

.bar-list {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.bar-row {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-family: var(--font-mono);
  font-size: 0.78rem;
}

.bar-label {
  flex: 0 0 auto;
  min-width: 4.5rem;
  color: var(--text-secondary);
  text-align: right;
}

.bar-track {
  flex: 1 1 auto;
  height: 14px;
  background: var(--bg-tertiary);
  border-radius: 3px;
  overflow: hidden;
}

.bar-fill {
  display: block;
  height: 100%;
  background: linear-gradient(90deg, var(--accent-active), var(--accent));
  border-radius: 3px;
  transition: width 0.4s ease;
}

.bar-value {
  flex: 0 0 auto;
  min-width: 5.5rem;
  color: var(--text-primary);
}

.state-table {
  display: flex;
  flex-direction: column;
  gap: 2px;
  font-family: var(--font-mono);
  font-size: 0.78rem;
}

.state-row {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 0.15rem 0;
  border-bottom: 1px solid var(--border-color);
}

.state-label-cell {
  min-width: 4.5rem;
  color: var(--text-secondary);
  text-align: right;
}

.state-value-cell {
  flex: 1 1 auto;
  color: var(--accent);
}

.state-prob-cell {
  min-width: 4rem;
  color: var(--text-muted);
  text-align: right;
}

.bloch-rail {
  flex: 0 0 auto;
  width: 96px;
  overflow-y: auto;
  overflow-x: hidden;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1rem 0.3rem;
  scrollbar-width: thin;
  scrollbar-color: var(--border-hover) transparent;
}

.bloch-rail::-webkit-scrollbar { width: 6px; }
.bloch-rail::-webkit-scrollbar-track { background: transparent; }
.bloch-rail::-webkit-scrollbar-thumb { background: var(--border-hover); border-radius: 3px; }

.bloch-rail-inner {
  display: grid;
  width: 100%;
  height: 100%;
}

.bloch-row-cell {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 0;
}

.bloch-row-svg {
  width: 100%;
  height: 100%;
  max-width: 84px;
  max-height: 84px;
  display: block;
}

/* ===== Toast ===== */
#toast-container {
  position: fixed;
  bottom: 1.5rem;
  left: 50%;
  transform: translateX(-50%);
  z-index: 2000;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
}

.toast {
  background: var(--bg-tertiary);
  border: 1px solid var(--border-hover);
  color: var(--text-primary);
  font-size: 0.82rem;
  padding: 0.6rem 1rem;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  animation: toast-in 0.2s ease;
}

@keyframes toast-in {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

.no-display {
  display: none !important;
}

/* ===== Responsive ===== */
@media (max-width: 900px) {
  .app-shell {
    flex-direction: column;
    height: auto;
    overflow: visible;
  }
  body {
    overflow-y: auto;
    height: auto;
  }
  #toolbox {
    width: 100%;
    border-left: none;
    border-top: 1px solid var(--border-color);
  }
  .navbar {
    flex-wrap: wrap;
    height: auto;
    padding: 0.6rem 1rem;
  }
  body {
    padding-top: 96px;
  }
}