/* ============================================================
   Full Adder Virtual Laboratory — Style Sheet
   PrayogSetu Interactive Digital Electronics Laboratory
   ============================================================ */

/* ── Reset & Base ──────────────────────────────────────────── */
*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  /* Laboratory Colour Palette (Light Mode Default) */
  --lab-bg: #f8fafc;
  --panel-bg: #ffffff;
  --panel-border: #e2e8f0;
  --header-bg: #0f172a;
  --header-text: #ffffff;
  --accent: #0284c7;
  --accent-light: #e0f2fe;
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #64748b;
  --success: #16a34a;
  --success-bg: #dcfce7;
  --danger: #dc2626;
  --wire-off: #94a3b8;
  --wire-on: #16a34a;
  --led-off: #64748b;
  --led-on: #22c55e;
  --led-glow: rgba(34, 197, 94, 0.5);
  --switch-track-off: #cbd5e1;
  --switch-track-on: #16a34a;
  --switch-knob: #ffffff;
  --gate-fill: #f1f5f9;
  --gate-stroke: #0f172a;
  --gate-active: #dcfce7;
  --submodule-fill: rgba(241, 245, 249, 0.65);
  --submodule-stroke: #cbd5e1;
  --submodule-title: #475569;
  --terminal-bg: #e2e8f0;
  --terminal-stroke: #cbd5e1;
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.10);
  --radius: 8px;
  --radius-lg: 12px;
  --font-sans: 'Inter', 'Segoe UI', -apple-system, sans-serif;
  --font-mono: 'JetBrains Mono', 'Cascadia Code', 'Consolas', monospace;
}

/* ── Dark Theme Overrides (Black Theme) ───────────────────── */
[data-theme="dark"],
html.dark {
  --lab-bg: #080d18;
  --panel-bg: #0f172a;
  --panel-border: #1e293b;
  --header-bg: #0b1120;
  --header-text: #f8fafc;
  --accent: #38bdf8;
  --accent-light: #1e3a5f;
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --success: #22c55e;
  --success-bg: #062d1f;
  --danger: #ef4444;
  --wire-off: #475569;
  --wire-on: #22c55e;
  --led-off: #334155;
  --led-on: #22c55e;
  --led-glow: rgba(34, 197, 94, 0.6);
  --switch-track-off: #334155;
  --switch-track-on: #22c55e;
  --switch-knob: #f8fafc;
  --gate-fill: #162036;
  --gate-stroke: #38bdf8;
  --gate-active: #064e3b;
  --submodule-fill: rgba(22, 32, 54, 0.45);
  --submodule-stroke: #263550;
  --submodule-title: #38bdf8;
  --terminal-bg: #162036;
  --terminal-stroke: #263550;
  --shadow-sm: 0 2px 6px rgba(0, 0, 0, 0.4);
  --shadow-md: 0 6px 18px rgba(0, 0, 0, 0.55);
}

html {
  font-size: 15px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  background: var(--lab-bg);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  transition: background-color 0.3s ease, color 0.3s ease;
}

/* ── Laboratory Title Bar ──────────────────────────────────── */
.lab-title-bar {
  background: var(--header-bg);
  color: var(--header-text);
  padding: 14px 28px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  position: sticky;
  top: 0;
  z-index: 100;
  border-bottom: 1px solid var(--panel-border);
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.25);
}

.lab-title-bar h1 {
  font-size: 1.2rem;
  font-weight: 700;
  letter-spacing: 0.3px;
  color: var(--header-text);
}

.lab-title-bar .lab-subtitle {
  font-size: 0.8rem;
  color: var(--text-muted);
  font-weight: 400;
  display: block;
}

.lab-badge {
  background: var(--accent);
  color: #fff;
  font-size: 0.68rem;
  padding: 4px 12px;
  border-radius: 999px;
  font-weight: 700;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  white-space: nowrap;
}

/* ── Main Layout ──────────────────────────────────────────── */
.lab-main {
  max-width: 1140px;
  margin: 0 auto;
  padding: 24px 20px 48px;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

/* ── Lab Panel ────────────────────────────────────────────── */
.lab-panel {
  background: var(--panel-bg);
  border: 1px solid var(--panel-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: background-color 0.3s ease, border-color 0.3s ease;
}

.lab-panel__header {
  background: var(--header-bg);
  color: var(--header-text);
  padding: 12px 20px;
  font-size: 0.88rem;
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 8px;
  border-bottom: 1px solid var(--panel-border);
}

.lab-panel__header .icon {
  font-size: 1rem;
}

.lab-panel__body {
  padding: 20px;
}

/* ── Input Controls Panel ─────────────────────────────────── */
.input-controls-body {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.input-control-group {
  display: flex;
  gap: 28px;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
}

.input-control {
  display: flex;
  align-items: center;
  gap: 14px;
  background: #ffffff;
  padding: 10px 20px;
  border-radius: var(--radius);
  border: 1px solid var(--panel-border);
  box-shadow: var(--shadow-sm);
  transition: all 0.3s ease;
}

[data-theme="dark"] .input-control {
  background: #111827;
  border-color: #263550;
}

.input-label {
  font-weight: 600;
  font-size: 1rem;
  color: var(--text-primary);
  min-width: 75px;
}

/* Toggle Switch Widget */
.toggle-btn {
  background: none;
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 0;
  outline: none;
  -webkit-tap-highlight-color: transparent;
}

.toggle-btn__track {
  width: 52px;
  height: 28px;
  background-color: var(--switch-track-off);
  border-radius: 14px;
  position: relative;
  transition: background-color 0.3s ease, box-shadow 0.3s ease;
  box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.2);
}

.toggle-btn__knob {
  width: 22px;
  height: 22px;
  background-color: var(--switch-knob);
  border-radius: 50%;
  position: absolute;
  top: 3px;
  left: 3px;
  transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.3);
}

.toggle-btn.high .toggle-btn__track {
  background-color: var(--switch-track-on);
  box-shadow: inset 0 1px 3px rgba(0, 0, 0, 0.1), 0 0 10px rgba(34, 197, 94, 0.4);
}

.toggle-btn.high .toggle-btn__knob {
  transform: translateX(24px);
}

.toggle-btn__state {
  font-family: var(--font-mono);
  font-size: 1.15rem;
  font-weight: 700;
  width: 24px;
  text-align: center;
  transition: color 0.3s ease;
}

.toggle-btn.low .toggle-btn__state {
  color: var(--danger);
}

.toggle-btn.high .toggle-btn__state {
  color: var(--success);
}

/* Control Buttons */
.lab-controls-row {
  display: flex;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
}

.btn {
  font-family: var(--font-sans);
  font-size: 0.88rem;
  font-weight: 600;
  padding: 8px 18px;
  border-radius: var(--radius);
  border: 1px solid var(--panel-border);
  background: #ffffff;
  color: var(--text-primary);
  cursor: pointer;
  transition: all 0.2s ease;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  box-shadow: var(--shadow-sm);
}

[data-theme="dark"] .btn {
  background: #1e293b;
  border-color: #334155;
  color: #f8fafc;
}

.btn:active {
  transform: translateY(1px);
}

.btn--primary {
  background: #0284c7 !important;
  color: #ffffff !important;
  border-color: #0284c7 !important;
}

.btn--primary:hover {
  background: #0369a1 !important;
  border-color: #0369a1 !important;
}

.btn--danger {
  background: #dc2626 !important;
  color: #ffffff !important;
  border-color: #dc2626 !important;
}

.btn--danger:hover {
  background: #b91c1c !important;
  border-color: #b91c1c !important;
}

/* ── Logic Circuit Canvas & SVG ────────────────────────────── */
.circuit-canvas {
  width: 100%;
  background: #ffffff;
  border: 1px solid var(--panel-border);
  border-radius: var(--radius);
  padding: 16px;
  overflow-x: auto;
  display: flex;
  justify-content: center;
  transition: background-color 0.3s ease, border-color 0.3s ease;
}

[data-theme="dark"] .circuit-canvas {
  background: #0b1222;
  border-color: #1e293b;
}

.circuit-canvas svg {
  width: 100%;
  height: auto;
  max-width: 940px;
  display: block;
}

/* SVG Circuit Elements */
.submodule-box {
  fill: var(--submodule-fill);
  stroke: var(--submodule-stroke);
  stroke-width: 1.5;
  stroke-dasharray: 6 4;
  transition: fill 0.3s ease, stroke 0.3s ease;
}

.submodule-title {
  font-family: var(--font-sans);
  font-size: 11px;
  font-weight: 700;
  fill: var(--submodule-title);
  letter-spacing: 1px;
  text-anchor: middle;
  transition: fill 0.3s ease;
}

.terminal-bg {
  fill: var(--terminal-bg);
  stroke: var(--terminal-stroke);
  stroke-width: 1.5;
  transition: fill 0.3s ease, stroke 0.3s ease;
}

.svg-label {
  font-family: var(--font-sans);
  font-size: 14px;
  font-weight: 700;
  fill: var(--text-primary);
  transition: fill 0.3s ease;
}

[data-theme="dark"] .svg-label {
  fill: #f8fafc;
}

.svg-value {
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  transition: fill 0.3s ease;
}

.svg-value.low {
  fill: var(--danger);
}

.svg-value.high {
  fill: var(--success);
  filter: drop-shadow(0 0 3px var(--success));
}

.wire {
  fill: none;
  stroke: var(--wire-off);
  stroke-width: 3.2;
  stroke-linecap: round;
  stroke-linejoin: round;
  transition: stroke 0.3s ease;
}

.wire.active {
  stroke: var(--wire-on);
  filter: drop-shadow(0 0 4px rgba(34, 197, 94, 0.6));
}

/* Animated Wire Signal Pulse */
.wire.animating {
  stroke-dasharray: 8 6;
  animation: wireFlow 0.8s linear infinite;
}

@keyframes wireFlow {
  to {
    stroke-dashoffset: -28;
  }
}

.junction-dot {
  fill: var(--wire-off);
  transition: fill 0.3s ease, filter 0.3s ease;
}

.junction-dot.active {
  fill: var(--wire-on);
  filter: drop-shadow(0 0 4px var(--wire-on));
}

.gate-body {
  fill: var(--gate-fill);
  stroke: var(--gate-stroke);
  stroke-width: 2.2;
  transition: fill 0.3s ease, stroke 0.3s ease, filter 0.3s ease;
}

.gate-group.active .gate-body {
  fill: var(--gate-active);
  stroke: var(--success);
  filter: drop-shadow(0 0 8px rgba(34, 197, 94, 0.35));
}

.gate-text {
  font-family: var(--font-sans);
  font-size: 11px;
  font-weight: 700;
  fill: var(--text-primary);
  text-anchor: middle;
  dominant-baseline: middle;
  pointer-events: none;
  transition: fill 0.3s ease;
}

[data-theme="dark"] .gate-text {
  fill: #f8fafc;
}

.signal-tag-bg {
  fill: var(--terminal-bg);
  stroke: var(--terminal-stroke);
  stroke-width: 1.2;
  transition: fill 0.3s ease, stroke 0.3s ease;
}

.signal-tag-text {
  font-family: var(--font-sans);
  font-size: 11px;
  font-weight: 600;
  fill: var(--text-secondary);
  text-anchor: middle;
  transition: fill 0.3s ease;
}

[data-theme="dark"] .signal-tag-text {
  fill: #94a3b8;
}

.val-highlight {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 12px;
}

.val-highlight.low {
  fill: var(--danger);
}

.val-highlight.high {
  fill: var(--success);
}

/* LEDs */
.led-housing {
  fill: var(--terminal-bg);
  stroke: var(--terminal-stroke);
  stroke-width: 1.5;
  transition: fill 0.3s ease, stroke 0.3s ease;
}

.led {
  fill: var(--led-off);
  transition: fill 0.3s ease, filter 0.3s ease;
}

.led.high {
  fill: var(--led-on);
  filter: drop-shadow(0 0 10px var(--led-glow));
}

.output-label {
  font-family: var(--font-sans);
  font-size: 13px;
  font-weight: 700;
  fill: var(--text-primary);
  transition: fill 0.3s ease;
}

[data-theme="dark"] .output-label {
  fill: #f8fafc;
}

.output-value {
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  transition: fill 0.3s ease;
}

.output-value.low {
  fill: var(--danger);
}

.output-value.high {
  fill: var(--success);
}

/* ── Output & Intermediate Values Panel ─────────────────────── */
.outputs-grid {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 16px;
  margin-bottom: 16px;
}

.output-card {
  background: #ffffff;
  border: 1px solid var(--panel-border);
  border-radius: var(--radius);
  padding: 14px 16px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  transition: all 0.3s ease;
}

[data-theme="dark"] .output-card {
  background: #111827;
  border-color: #263550;
}

.card-label {
  font-size: 0.78rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--text-secondary);
  letter-spacing: 0.5px;
  border-bottom: 1px solid var(--panel-border);
  padding-bottom: 6px;
}

.main-indicators-row {
  display: flex;
  gap: 16px;
  justify-content: space-around;
  align-items: center;
  height: 100%;
}

.indicator-box {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
}

.ind-name {
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.ind-val {
  font-family: var(--font-mono);
  font-size: 1.8rem;
  font-weight: 800;
  width: 52px;
  height: 52px;
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  background: #f1f5f9;
  color: var(--danger);
  border: 1px solid var(--panel-border);
  transition: all 0.3s ease;
}

[data-theme="dark"] .ind-val {
  background: #162036;
  border-color: #263550;
  color: var(--danger);
}

.ind-val.high {
  background: var(--success-bg) !important;
  color: var(--success) !important;
  border-color: var(--success) !important;
  box-shadow: 0 0 12px rgba(34, 197, 94, 0.25);
}

.internal-indicators-row {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.sub-indicator {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.85rem;
  background: #f8fafc;
  border: 1px solid var(--panel-border);
  padding: 6px 10px;
  border-radius: 4px;
  transition: all 0.3s ease;
}

[data-theme="dark"] .sub-indicator {
  background: #162036;
  border-color: #263550;
}

.sub-name {
  color: var(--text-secondary);
  font-weight: 500;
}

.sub-val {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 0.95rem;
  padding: 2px 8px;
  border-radius: 4px;
  background: #e2e8f0;
  color: var(--danger);
  transition: all 0.3s ease;
}

[data-theme="dark"] .sub-val {
  background: #0f172a;
  color: var(--danger);
}

.sub-val.high {
  background: var(--success-bg) !important;
  color: var(--success) !important;
}

.equations-list {
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-size: 0.8rem;
}

.eq-item code {
  font-family: var(--font-mono);
  background: #f1f5f9;
  border: 1px solid var(--panel-border);
  padding: 3px 6px;
  border-radius: 4px;
  color: var(--text-primary);
  display: block;
}

[data-theme="dark"] .eq-item code {
  background: #162036;
  border-color: #263550;
  color: #38bdf8;
}

/* Verification Banner */
.verification-bar {
  background: var(--success-bg);
  border: 1px solid var(--success);
  color: #14532d;
  padding: 12px 18px;
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  gap: 12px;
  font-weight: 600;
  font-size: 0.92rem;
  box-shadow: var(--shadow-sm);
  transition: all 0.3s ease;
}

[data-theme="dark"] .verification-bar {
  background: #062d1f;
  border-color: #22c55e;
  color: #86efac;
}

.ver-icon {
  font-size: 1.2rem;
  font-weight: 800;
}

/* ── Truth Table Panel ─────────────────────────────────────── */
.tt-wrapper {
  overflow-x: auto;
}

.truth-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
  background: #ffffff;
  transition: all 0.3s ease;
}

[data-theme="dark"] .truth-table {
  background: #111827;
}

.truth-table th,
.truth-table td {
  padding: 10px 16px;
  text-align: center;
  border: 1px solid var(--panel-border);
}

.truth-table th {
  background: var(--header-bg);
  color: var(--header-text);
  font-weight: 700;
}

.truth-table th.col-highlight {
  background: #0284c7;
  color: #ffffff;
}

[data-theme="dark"] th.col-highlight {
  background: #1e3a5f;
  color: #38bdf8;
}

.truth-table td {
  font-family: var(--font-mono);
  color: var(--text-primary);
}

.truth-table tbody tr {
  background: #ffffff;
  transition: background 0.3s ease;
}

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

[data-theme="dark"] .truth-table tbody tr {
  background: #111827;
  color: #f8fafc;
}

[data-theme="dark"] .truth-table tbody tr:nth-child(even) {
  background: #0e1526;
}

.truth-table tr.active-row {
  background: #dcfce7 !important;
  font-weight: 700;
}

[data-theme="dark"] .truth-table tr.active-row {
  background: #062d1f !important;
}

.truth-table tr.active-row td {
  border-color: var(--success);
  color: var(--success);
  font-weight: 700;
}

.truth-table tr.active-row .status-cell::after {
  content: "◄ Active";
  font-family: var(--font-sans);
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--success);
}

/* ── Educational Theory Panel ──────────────────────────────── */
.theory-content {
  font-size: 0.92rem;
  color: var(--text-primary);
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.theory-content h3 {
  font-size: 1.05rem;
  color: var(--text-primary);
  margin-top: 8px;
}

.theory-list {
  padding-left: 20px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.theory-submodules-grid {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 16px;
  margin-top: 10px;
}

.theory-card {
  background: #ffffff;
  border: 1px solid var(--panel-border);
  border-radius: var(--radius);
  padding: 14px;
  transition: all 0.3s ease;
}

[data-theme="dark"] .theory-card {
  background: #111827;
  border-color: #263550;
}

.theory-card h4 {
  font-size: 0.9rem;
  color: var(--accent);
  margin-bottom: 6px;
}

.theory-card ul {
  padding-left: 18px;
  font-size: 0.85rem;
  margin-top: 6px;
}

/* ── Responsive Layout Adaptations ─────────────────────────── */
@media (max-width: 900px) {

  .outputs-grid,
  .theory-submodules-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 600px) {
  .input-control-group {
    flex-direction: column;
    gap: 12px;
  }

  .lab-title-bar {
    padding: 12px 16px;
  }

  .lab-title-bar h1 {
    font-size: 1.05rem;
  }
}