:root {
  --bg1: linear-gradient(135deg, #f5f7fa 0%, #e6eef8 100%);
  --panel-bg: rgba(255, 255, 255, 0.98);
  --glass-bg: rgba(230, 235, 245, 0.65); /* Glassmorphism background */
  --accent1: #667eea;
  --accent2: #764ba2;
  --muted: #94a3b8;
  --success: #38a169;
  --danger: #e53e3e;
}

body[data-theme="ocean"] {
  --bg1: linear-gradient(135deg, #e0f2fe 0%, #dbeafe 100%);
  --accent1: #0284c7;
  --accent2: #0f766e;
}

body[data-theme="forest"] {
  --bg1: linear-gradient(135deg, #ecfdf5 0%, #dcfce7 100%);
  --accent1: #15803d;
  --accent2: #166534;
}

body[data-theme="sunset"] {
  --bg1: linear-gradient(135deg, #fff7ed 0%, #ffedd5 100%);
  --accent1: #ea580c;
  --accent2: #c2410c;
}

* {
  box-sizing: border-box;
}

html,
body {
  height: 100%;
  margin: 0;
  font-family: Inter, system-ui, -apple-system, Segoe UI, Roboto, Arial;
  background: var(--bg1);
  color: #0b1220;
  -webkit-font-smoothing: antialiased;
}

html[data-font-scale="large"] {
  font-size: 17px;
}

html[data-font-scale="xlarge"] {
  font-size: 19px;
}

body[data-motion="reduced"] *,
body[data-motion="reduced"] *::before,
body[data-motion="reduced"] *::after {
  animation-duration: 0.01ms !important;
  animation-iteration-count: 1 !important;
  transition-duration: 0.01ms !important;
  scroll-behavior: auto !important;
}

.app-container {
  max-width: 1400px;
  margin: 12px auto;
  padding: 18px;
  display: flex;
  flex-direction: column;
  gap: 14px;
  height: calc(100vh - 24px); /* Make app container fill the height */
}

.header {
  background: linear-gradient(90deg, var(--accent1), var(--accent2));
  padding: 8px 14px;
  border-radius: 12px;
  color: #fff;
  box-shadow: 0 6px 20px rgba(2, 6, 23, 0.4);
  display: flex;
  justify-content: space-between;
  align-items: center;
  position: relative; 
  flex-shrink: 0; /* Prevent header from shrinking */
}
.header h1 {
  font-size: 1.2rem;
  margin: 0;
}

.main-content {
  display: flex;
  gap: 20px;
  align-items: flex-start;
  position: relative;
  flex-grow: 1; /* Allow main content to grow */
  min-height: 0; /* Flexbox bug fix */
}

.control-panel {
  width: 280px;
  flex-shrink: 0;
  position: sticky;
  top: 20px; /* Adjust sticky position */
  display: flex;
  flex-direction: column;
  gap: 12px;
  max-height: calc(100vh - 120px); /* Ensure it doesn't overflow */
  overflow-y: auto; /* Allow scrolling if needed */
}

/* --- NEW: Main column for canvas and log --- */
.main-column {
    flex-grow: 1;
    display: flex;
    flex-direction: column;
    gap: 12px;
    min-width: 0; /* Flexbox bug fix */
}


/* --- NEW SECTION STYLING --- */
details.control-section {
    background: transparent;
    border: none;
    padding: 0;
}

.control-section summary {
    list-style: none;
    display: flex;
    align-items: center;
    gap: 8px;
    font-weight: 600;
    color: #4a5568; /* Dark text */
    padding: 10px 4px;
    cursor: pointer;
}
.control-section summary::-webkit-details-marker {
    display: none;
}

/* The content area that gets the background when open */
.control-section .control-section-content {
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border-radius: 14px;
    padding: 18px;
    border: 1px solid rgba(255, 255, 255, 0.2);
    box-shadow: 0 4px 12px rgba(0,0,0,0.05);
}
/* --- END NEW SECTION STYLING --- */


.control-panel select,
.control-panel input,
.control-panel textarea,
.control-panel .icon-btn,
.control-panel #practiceBox,
.control-panel #bulkTestOutput,
#libraryList > div {
    background: #fff;
    border: 1px solid #e6eef8;
    border-radius: 10px;
    padding: 10px;
    width: 100%;
}
#randomStringBox, #testOptionsCollapse summary {
    margin: 6px 0; font-size: 0.9em; 
    background: linear-gradient(90deg,#fff,#f7fafc); 
    padding: 6px 8px; border-radius: 8px;
}
#bulkTestOutput, #practiceBox, .output-display {
    margin-top: 10px;
    padding: 10px;
    border-radius: 10px;
    background: linear-gradient(180deg,#fff,#fbfdff);
    border: 1px solid #eef2ff;
    min-height: 60px;
}


.visualization-panel {
  flex-grow: 1; /* Allow canvas to take up available space */
  background: var(--panel-bg);
  border-radius: 14px;
  padding: 16px;
  border: 1px solid rgba(255, 255, 255, 0.12);
  display: flex;
  flex-direction: column;
  gap: 12px;
  min-height: 300px; /* Ensure it doesn't collapse */
}

.icon-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 10px;
  cursor: pointer;
  font-weight: 600;
}

.toolbar-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 46px;
  height: 46px;
  border-radius: 10px;
  border: 1px solid rgba(0, 0, 0, 0.06);
  background: linear-gradient(180deg, #fff, #f7fafc);
  cursor: pointer;
  transition: transform 0.2s, box-shadow 0.2s;
}
.toolbar-icon svg {
    width: 24px;
    height: 24px;
    stroke-width: 2.5;
}


.toolbar-icon.active {
  background: linear-gradient(90deg, var(--accent1), var(--accent2));
  color: #fff;
  box-shadow: 0 6px 18px rgba(99, 102, 241, 0.18);
  transform: translateY(-2px);
}
.toolbar-icon.active svg { stroke: #fff !important; }

/* --- Colorful Toolbar Icons --- */
.toolbar-icon#tool-addclick svg { stroke: #4caf50; }
.toolbar-icon#tool-move svg { stroke: #2196f3; }
.toolbar-icon#tool-transition svg { stroke: #9c27b0; }
.toolbar-icon#tool-rename svg { stroke: #009688; }
.toolbar-icon#tool-delete svg { stroke: #f44336; }
.toolbar-icon#tool-stateprops svg { stroke: #607d8b; }
.toolbar-icon#clearCanvasBtn svg { stroke: #f44336; }
.toolbar-icon#undoBtn svg, .toolbar-icon#redoBtn svg { stroke: #607d8b; }
.toolbar-icon#validateBtn svg {stroke: #4caf50;}

/* --- Colorful Control Panel Section Icons --- */
.control-section summary [data-lucide='sliders-horizontal'] { stroke: #2196f3; }
.control-section summary [data-lucide='puzzle'] { stroke: #9c27b0; }
.control-section summary [data-lucide='flask-conical'] { stroke: #009688; }
.control-section summary [data-lucide='folder'] { stroke: #ff9800; }
.control-section summary [data-lucide='library'] { stroke: #e91e63; }
.control-section summary [data-lucide='wand-2'] { stroke: #7c3aed; }


.toolbar-icon:hover {
  transform: scale(1.15);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

.canvas-wrapper {
  background: #fff;
  border-radius: 12px;
  padding: 12px;
  border: 1px solid #e6eef8;
  flex: 1;
  display: flex;
  flex-direction: column;
}

.canvas-toolbar {
  display: flex;
  gap: 8px;
  margin-bottom: 8px;
  z-index: 30;
  background: linear-gradient(180deg, #ffffff, #fbfdff);
  padding: 8px;
  box-shadow: 0 6px 18px rgba(0, 0, 0, 0.06);
  border-bottom: 1px solid rgba(0, 0, 0, 0.04);
  position: relative;
  flex-wrap: wrap;
}

.canvas-area {
  flex: 1;
  display: flex;
  overflow: auto;
}

.svg-canvas {
  flex: 1;
  border-radius: 10px;
  border: 1px dashed #e6eef8;
  overflow: hidden;
  padding: 8px;
  background: linear-gradient(180deg, #ffffff, #fbfdff);
}

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

.zoom-controls {
  position: absolute;
  right: 30px;
  top: 150px;
  z-index: 50;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
}
.zoom-controls button { all: unset; }
.zoom-controls .toolbar-icon { width: 40px; height: 40px; margin: 2px; }

.test-panel { display: flex; gap: 12px; align-items: center; }
.input { flex: 1; display: flex; gap: 8px; }
.input input { flex: 1; }

.run-btn {
  padding: 10px 12px;
  border: none;
  background: linear-gradient(90deg, var(--accent1), var(--accent2));
  color: #fff;
  cursor: pointer;
  font-weight: 700;
}

.state-circle {
  fill: #fff;
  stroke: var(--accent1);
  stroke-width: 3;
  cursor: pointer;
}
.state-label {
  font-weight: 700;
  fill: #0b1220;
  text-anchor: middle;
  dominant-baseline: central;
  font-size: 14px;
  pointer-events: none;
}

.transition-path {
  fill: none;
  stroke: var(--accent1);
  stroke-width: 2;
  marker-end: url(#arrowhead);
}

.transition-label-text {
    stroke: white;
    stroke-width: 4px;
    stroke-linejoin: round;
    fill: none; 
    pointer-events: all;
    cursor: default;
    text-anchor: middle;
    font-size: 13px;
    font-weight: 700;
}

.transition-label {
    font-weight: 700;
    fill: #0b1220; 
    text-anchor: middle;
    font-size: 13px;
    pointer-events: none; 
}

.mode-delete .transition-label-text {
    cursor: pointer;
}
.mode-delete .transition-label-text:hover + .transition-label {
    fill: var(--danger);
}


.kv { font-size: 13px; color: var(--muted); }

.canvas-wrapper::-webkit-scrollbar { height: 10px; width: 10px; }
.canvas-wrapper::-webkit-scrollbar-thumb { background: linear-gradient(90deg, var(--accent1), var(--accent2)); border-radius: 10px; }

@keyframes pulseState {
    0% { stroke-width: 3; filter: drop-shadow(0 0 2px gold); }
    50% { stroke-width: 6; filter: drop-shadow(0 0 10px orange); }
    100% { stroke-width: 3; filter: drop-shadow(0 0 2px gold); }
}
@keyframes pulseTransition {
    0% { stroke-width: 2; filter: drop-shadow(0 0 2px gold); }
    50% { stroke-width: 5; filter: drop-shadow(0 0 8px orange); }
    100% { stroke-width: 2; filter: drop-shadow(0 0 2px gold); }
}
.state-animating { animation: pulseState 0.8s ease-in-out forwards; }
.transition-animating { animation: pulseTransition 0.8s ease-in-out forwards; }

@keyframes drawState {
  0% { opacity: 0; transform: scale(0); }
  60% { opacity: 1; transform: scale(1.15); }
  100% { opacity: 1; transform: scale(1); }
}
@keyframes drawTransition {
  0% { stroke-dashoffset: 1000; opacity: 0; }
  100% { stroke-dashoffset: 0; opacity: 1; }
}
.state-drawing { animation: drawState 0.6s ease-out forwards; transform-origin: center; }
.transition-drawing { stroke-dasharray: 1000; animation: drawTransition 0.8s ease-out forwards; }

.state-selected { stroke: gold !important; stroke-width: 6 !important; filter: drop-shadow(0 0 6px gold); }
.initial-arrow { stroke: black !important; stroke-width: 3 !important; marker-end: url(#arrowhead); }

#zoomSlider {
  writing-mode: vertical-lr;
  direction: rtl;
  width: 8px;
  height: 120px;
}
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.4);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 200;
}
.modal-box {
  background: rgba(255, 255, 255, 0.95);
  border-radius: 18px;
  padding: 20px;
  max-width: 360px;
  width: 92%;
  backdrop-filter: blur(10px) saturate(180%);
  box-shadow: 0 8px 28px rgba(0, 0, 0, 0.4);
  animation: modalPop 0.35s ease-out;
  border: 1px solid rgba(255, 255, 255, 0.2);
}
.modal-actions { display: flex; gap: 8px; justify-content: flex-end; }
.modal-input {
  width: 100%;
  padding: 10px 12px;
  border-radius: 12px;
  border: 2px solid rgba(102, 126, 234, 0.5);
  background: rgba(255, 255, 255, 0.7);
  font-size: 0.95rem;
  margin-bottom: 14px;
  transition: all 0.25s ease;
}
.modal-input:focus {
  border-color: var(--accent1);
  background: #f0f5ff;
  box-shadow: 0 0 8px rgba(102, 126, 234, 0.5);
  outline: none;
}
.final-ring {
  fill: none;
  stroke: #ff9800;
  stroke-width: 4;
  filter: drop-shadow(0 0 8px rgba(255, 152, 0, 0.7));
  vector-effect: non-scaling-stroke;
}
.control-row { display: flex; gap: 6px; margin: 4px 0; }
.control-row button {
  flex: 1;
  padding: 8px;
  border-radius: 8px;
  border: none;
  background: var(--accent2);
  color: #fff;
  cursor: pointer;
}
.control-row button:hover { opacity: 0.85; }

.validation-box {
  border: 1px solid #cbd5e1;
  padding: 6px 10px;
  border-radius: 8px;
  font-size: 13px;
  margin-left: 8px;
  display: none;
  transition: opacity 0.25s ease, transform 0.25s ease;
}
.validation-box.show { display: inline-block; }
.validation-box.success { border-color: #38a169; color: #065f46; background: #ecfdf5; }
.validation-box.error { border-color: #e53e3e; color: #7f1d1d; background: #fef2f2; }

#stepLog {
  max-height: 10em;
  overflow-y: auto;
  border-radius: 8px;
  padding: 8px 12px;
  font-family: monospace;
  font-size: 0.9em;
  background: linear-gradient(180deg, #1e293b, #0f172a);
  color: #f8fafc;
  box-shadow: inset 0 0 6px rgba(0, 0, 0, 0.4);
  flex-shrink: 0; /* Prevent log from shrinking */
}
#stepLog div { padding: 4px 6px; border-bottom: 1px solid rgba(255, 255, 255, 0.1); display: flex; align-items: center; gap: 6px; }
#stepLog div:last-child { border-bottom: none; }
#stepLog svg { color: #38bdf8; }

button:disabled { opacity: 0.5; cursor: not-allowed; }

.modal-box h3 {
  margin: 0 0 12px 0;
  font-size: 1.25rem;
  font-weight: 700;
  background: linear-gradient(90deg, var(--accent1), var(--accent2));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}
.modal-actions button {
  padding: 8px 14px;
  border-radius: 10px;
  font-weight: 600;
  border: none;
  cursor: pointer;
  transition: all 0.25s ease;
}
.modal-actions button:first-child { background: #e5e7eb; color: #111827; }
.modal-actions button:first-child:hover { background: #d1d5db; }
.modal-actions button:last-child { background: linear-gradient(90deg, var(--accent1), var(--accent2)); color: #fff; }
.modal-actions button:last-child:hover { opacity: 0.9; transform: scale(1.05); }

@keyframes modalPop {
  0% { transform: scale(0.85) translateY(20px); opacity: 0; }
  100% { transform: scale(1) translateY(0); opacity: 1; }
}

.svg-canvas { transition: transform 0.22s cubic-bezier(.2, .9, .2, 1); }
.state-circle { transition: stroke-width 0.18s ease, transform 0.18s ease; }

.panel-toggle-btn {
    display: none;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    border: none;
    background: rgba(255, 255, 255, 0.2);
    backdrop-filter: blur(8px);
    color: white;
    cursor: pointer;
    align-items: center;
    justify-content: center;
}

.drawer-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, 0.45);
  backdrop-filter: blur(2px);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.25s ease;
  z-index: 90;
}

.drawer-backdrop.open {
  opacity: 1;
  pointer-events: auto;
}

@media (max-width: 1024px) {
  .app-container {
      margin: 0;
      padding: 12px;
      height: 100dvh;
      max-width: 100%;
      border-radius: 0;
  }
  .header {
      position: sticky;
      top: 0;
      z-index: 200;
  }
  .header h1 {
      font-size: 1.05rem;
      line-height: 1.2;
  }
  .panel-toggle-btn { display: flex; }
  .main-content { flex-direction: column; }
  .control-panel {
    position: fixed;
    top: 78px;
    left: 12px;
    width: 320px;
    height: auto;
    max-height: calc(100dvh - 92px);
    z-index: 100;
    transform: scale(0.95) translateX(-120%);
    opacity: 0;
    pointer-events: none;
    transition: transform 0.3s ease-in-out, opacity 0.3s ease-in-out;
    background: transparent;
    border: none;
    padding: 0;
    overflow-y: auto;
    overflow-x: hidden;
  }
  .control-panel.open {
    transform: scale(1) translateX(0);
    opacity: 1;
    pointer-events: auto;
  }
  
  .control-panel.open .control-section {
    background: transparent;
    border: none;
    padding: 0;
    margin-bottom: 12px;
  }

  .control-panel.open .control-section-header,
  .control-panel.open details {
      background: rgba(15, 23, 42, 0.75);
      backdrop-filter: blur(12px);
      border: 1px solid rgba(255, 255, 255, 0.2);
      color: #f1f5f9;
      border-radius: 14px;
      padding: 18px;
  }

  .control-panel.open summary {
      width: fit-content;
  }
  
  .control-panel.open .control-section-header,
  .control-panel.open summary {
      color: #f8fafc;
      padding: 0;
  }
    
  .control-panel.open select,
  .control-panel.open input,
  .control-panel.open textarea,
  .control-panel.open .icon-btn,
  .control-panel.open #practiceBox,
  .control-panel.open #bulkTestOutput,
  .control-panel.open #libraryList > div {
      background: rgba(30, 41, 59, 0.8);
      border-color: rgba(255, 255, 255, 0.3);
      color: #f8fafc;
  }
  .control-panel.open #practiceBox, .control-panel.open #bulkTestOutput {
      color: #cbd5e1;
  }

  /* On smaller screens, the main column takes full width */
  .main-column {
      width: 100%;
  }
  .visualization-panel {
      width: 100%;
      height: calc(100dvh - 150px);
  }
}

@media (max-width: 768px) {
  .header {
      padding: 8px 10px;
      gap: 8px;
  }
  .header h1 {
      font-size: 0.98rem;
  }
  .panel-toggle-btn {
      width: 36px;
      height: 36px;
  }
  .zoom-controls {
      right: 12px;
      top: auto;
      bottom: 12px;
      flex-direction: row;
      background: rgba(255, 255, 255, 0.92);
      border: 1px solid #e2e8f0;
      border-radius: 12px;
      padding: 6px;
  }
  .canvas-wrapper {
      padding: 8px;
  }
  .toolbar-icon {
      width: 42px;
      height: 42px;
  }
  #pdaStackHeader,
  #tmTapeHeader {
      display: none;
  }
}


@media (max-width: 600px) {
  .app-container {
      padding: 10px;
  }
  .control-panel {
      width: calc(100% - 24px);
      left: 12px;
      top: 72px;
      max-height: calc(100dvh - 86px);
  }
  .visualization-panel {
      height: calc(100dvh - 140px);
      padding: 10px;
  }
  .canvas-toolbar {
      padding: 6px;
      gap: 6px;
  }
}

@media (min-width: 1025px) {
  .drawer-backdrop {
      display: none;
  }
}

.splash-screen {
  position: fixed;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 28px;
  color: #fff;
  z-index: 9999;
  overflow: hidden;
  background:
    radial-gradient(circle at 20% 20%, rgba(56, 189, 248, 0.35), transparent 35%),
    radial-gradient(circle at 82% 30%, rgba(45, 212, 191, 0.28), transparent 40%),
    linear-gradient(150deg, #0f172a 0%, #1d4ed8 45%, #0f766e 100%);
  transition: opacity 0.5s ease;
}

.splash-shell {
  width: min(1060px, 100%);
  border: 1px solid rgba(255, 255, 255, 0.25);
  border-radius: 24px;
  background: rgba(15, 23, 42, 0.35);
  backdrop-filter: blur(14px);
  padding: clamp(18px, 3vw, 34px);
  box-shadow: 0 24px 70px rgba(2, 6, 23, 0.38);
  display: grid;
  gap: 14px;
  position: relative;
}

.splash-kicker {
  width: fit-content;
  padding: 5px 10px;
  border-radius: 999px;
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  font-weight: 700;
  text-transform: uppercase;
  color: #ecfeff;
  background: rgba(6, 182, 212, 0.28);
  border: 1px solid rgba(255, 255, 255, 0.32);
}

.splash-title {
  margin: 0;
  font-size: clamp(1.7rem, 5vw, 3.2rem);
  line-height: 1.1;
}

.splash-student {
  margin: 0;
  width: fit-content;
  max-width: 100%;
  padding: 7px 12px;
  border-radius: 999px;
  border: 1px solid rgba(255, 255, 255, 0.28);
  background: rgba(255, 255, 255, 0.12);
  font-weight: 600;
  font-size: 0.94rem;
}

.splash-tabs {
  width: 100%;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
  gap: 10px;
}

.splash-nav-btn {
  border: 1px solid rgba(255, 255, 255, 0.35);
  border-radius: 14px;
  padding: 14px 12px;
  background: rgba(255, 255, 255, 0.13);
  color: #fff;
  font-size: 0.98rem;
  font-weight: 700;
  cursor: pointer;
  transition: transform 0.2s ease, background 0.2s ease, border-color 0.2s ease;
}

.splash-nav-btn:hover {
  transform: translateY(-1px);
  background: rgba(255, 255, 255, 0.2);
  border-color: rgba(255, 255, 255, 0.55);
}

.splash-nav-btn:disabled {
  opacity: 0.55;
  cursor: not-allowed;
}

#splashUtilityRow {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.splash-utility-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 999px;
  padding: 10px 14px;
  border: 1px solid rgba(255, 255, 255, 0.35);
  background: rgba(15, 23, 42, 0.35);
  color: #f8fafc;
  font-weight: 700;
  font-size: 0.92rem;
  text-decoration: none;
  transition: background 0.2s ease, transform 0.2s ease;
}

.splash-utility-btn:hover {
  background: rgba(255, 255, 255, 0.18);
  transform: translateY(-1px);
}

.splash-orb {
  position: absolute;
  border-radius: 999px;
  filter: blur(1px);
  opacity: 0.4;
}

.splash-orb-1 {
  width: 280px;
  height: 280px;
  left: -70px;
  top: -50px;
  background: radial-gradient(circle, #67e8f9, transparent 70%);
}

.splash-orb-2 {
  width: 280px;
  height: 280px;
  right: -90px;
  bottom: -70px;
  background: radial-gradient(circle, #2dd4bf, transparent 70%);
}

.splash-dialog {
  max-width: 620px;
}

.help-step-content {
  background: #f8fafc;
  border: 1px solid #e2e8f0;
  border-radius: 12px;
  padding: 12px;
  min-height: 150px;
  line-height: 1.5;
  font-size: 0.95rem;
}

.help-step-progress {
  margin-top: 10px;
  font-size: 0.85rem;
  color: #64748b;
}

.integration-status {
  background: #f8fafc;
  border: 1px solid #e2e8f0;
  border-radius: 10px;
  padding: 10px;
  margin-bottom: 14px;
  font-size: 0.85rem;
  display: grid;
  gap: 6px;
}

#localModeNotice {
  position: fixed;
  top: 10px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 10001;
  max-width: min(920px, 92vw);
  background: #fff7ed;
  border: 1px solid #fdba74;
  color: #7c2d12;
  padding: 10px 14px;
  border-radius: 10px;
  font-size: 0.9rem;
  box-shadow: 0 8px 18px rgba(0, 0, 0, 0.12);
}

@media (max-width: 520px) {
  .splash-screen {
      padding: 14px;
  }
  .splash-shell {
      gap: 12px;
      padding: 16px;
  }
  .splash-tabs {
      grid-template-columns: 1fr;
  }
  #splashUtilityRow {
      display: grid;
      grid-template-columns: 1fr 1fr;
  }
}

.modal-description { margin: 4px 0 12px 0; font-size: 0.9em; color: #555; line-height: 1.5; }
.danger-btn { background: #e53e3e !important; color: #fff !important; }
.danger-btn:hover { background: #c53030 !important; }

.modal-prop-row { margin-bottom: 12px; }
.modal-prop-row label { display: flex; align-items: center; gap: 8px; font-size: 1rem; }
.modal-prop-row input[type="checkbox"] { width: 1.3em; height: 1.3em; accent-color: var(--accent1); }

@keyframes pulseInitial {
  0%, 100% {
    filter: drop-shadow(0 0 6px rgba(59, 130, 246, 0.6)) 
            drop-shadow(0 0 12px rgba(59, 130, 246, 0.3));
  }
  50% {
    filter: drop-shadow(0 0 10px rgba(96, 165, 250, 1)) 
            drop-shadow(0 0 22px rgba(96, 165, 250, 0.6));
  }
}

.initial-pulse {
  animation: pulseInitial 2.2s infinite ease-in-out;
}

/* --- ENHANCED TOOLBAR & UX --- */

/* Base style for icons to ensure they are visible and crisp */
.toolbar-icon i, .toolbar-icon svg {
    width: 20px;
    height: 20px;
    stroke-width: 2.5px;
    transition: stroke 0.2s;
}

/* THE FIX: Active state - Colorful and distinct */
.toolbar-icon.active {
    background: linear-gradient(90deg, var(--accent1), var(--accent2)) !important;
    color: #fff !important;
    box-shadow: 0 6px 18px rgba(99, 102, 241, 0.3);
    transform: translateY(-2px);
    border-color: transparent;
}

/* Ensure Lucide icons turn white when the button is active */
.toolbar-icon.active i, .toolbar-icon.active svg {
    stroke: #ffffff !important;
}

/* Delete/Clear button hover specialty */
.delete-btn:hover {
    background: #fee2e2 !important; /* Soft red bg */
}
.delete-btn:hover i {
    stroke: #ef4444 !important;
}

/* Disabled icons for Undo/Redo */
.toolbar-icon:disabled {
    opacity: 0.3;
    cursor: not-allowed;
    background: #f1f5f9;
}

/* --- Live Stack Visualizer --- */
.stack-visualizer {
    display: flex;
    flex-direction: column-reverse; /* Items added to top */
    align-items: center;
    gap: 4px;
    padding: 10px;
    background: #f1f5f9;
    border-radius: 8px;
    min-height: 200px;
    max-height: 400px;
    overflow-y: auto;
    border: 2px inset rgba(0,0,0,0.05);
}

.stack-item {
    width: 80%;
    padding: 8px;
    background: white;
    border: 1px solid #e2e8f0;
    border-radius: 4px;
    text-align: center;
    font-weight: 700;
    font-family: monospace;
    color: var(--accent2);
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
    transition: transform 0.2s;
}

/* Highlight the top-most item */
.stack-item.stack-top {
    background: var(--accent1);
    color: white;
    border-color: var(--accent1);
    transform: scale(1.05);
    box-shadow: 0 4px 10px rgba(99, 102, 241, 0.3);
}

/* --- Control Panel Button Optimization --- */

/* Fix for side-by-side buttons in control-row */
.control-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 8px; /* Slightly wider gap for clarity */
    margin-bottom: 8px;
}

.control-row .icon-btn {
    width: auto !important; /* Allow buttons to fit the grid column */
    min-width: 0;           /* Prevent flex-clipping */
    justify-content: center; /* Center content horizontally */
    font-size: 0.85rem;     /* Slightly smaller text for better fit */
    padding: 10px 5px;      /* Tighter horizontal padding */
}

/* Ensure icons in control buttons are consistently sized */
.icon-btn i, .icon-btn svg {
    width: 16px;
    height: 16px;
    flex-shrink: 0;
}

/* Hover effect for the File buttons to match the colorful theme */
#savePdaBtn:hover, #loadPdaBtn:hover {
    background: #f0f4ff;
    border-color: var(--accent1);
    color: var(--accent1);
}

#pdaExportPngBtn:hover {
    background: #fff7ed;
    border-color: #ff9800;
    color: #ff9800;
}

/* --- PRACTICE GLOW SYSTEM --- */

/* Turing Machine: Emerald */
.practice-tm-active {
  border: 2px solid #10b981 !important;
  box-shadow: 0 0 15px rgba(16, 185, 129, 0.4);
  background: #f0fdf4 !important;
}

/* PDA: Indigo */
.practice-pda-active {
  border: 2px solid #6366f1 !important;
  box-shadow: 0 0 15px rgba(99, 102, 241, 0.4);
  background: #f5f3ff !important;
}

/* Finite Automata: Blue */
.practice-fa-active {
  border: 2px solid #3b82f6 !important;
  box-shadow: 0 0 15px rgba(59, 130, 246, 0.4);
  background: #eff6ff !important;
}

/* Mealy/Moore: Orange */
.practice-mm-active {
  border: 2px solid #f59e0b !important;
  box-shadow: 0 0 15px rgba(245, 158, 11, 0.4);
  background: #fffbeb !important;
}

/* --- TM SPECIFIC FILE HOVER EFFECTS --- */

/* Emerald highlight for Save/Load buttons */
.tm-file-btn:hover {
    background: #f0fdf4 !important; /* Soft Emerald tint */
    border-color: #10b981 !important;
    color: #065f46 !important;
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(16, 185, 129, 0.15);
}

.tm-file-btn:hover i {
    stroke: #10b981 !important;
}

/* Emerald highlight for PNG Export */
.tm-export-btn:hover {
    background: #f0fdf4 !important;
    border-color: #059669 !important;
    color: #059669 !important;
}

.tm-export-btn:hover i {
    stroke: #059669 !important;
}

/* Ensure TM icons follow the Emerald theme in the toolbar */
.toolbar-icon#tm-tool-add svg,
.toolbar-icon#tm-tool-trans svg {
    stroke: #10b981;
}

/* Grammar Studio */
.grammar-page {
  background:
    radial-gradient(circle at 12% 15%, rgba(14, 165, 233, 0.22), transparent 30%),
    radial-gradient(circle at 86% 8%, rgba(20, 184, 166, 0.2), transparent 32%),
    var(--bg1);
}

.grammar-app {
  height: auto;
  min-height: calc(100vh - 24px);
}

.grammar-header {
  background: linear-gradient(90deg, #0ea5e9, #0f766e);
  padding: 12px 16px;
}

.grammar-subtitle {
  margin: 4px 0 0 0;
  font-size: 0.86rem;
  opacity: 0.92;
}

.grammar-back-btn {
  background: rgba(15, 23, 42, 0.24);
  border-color: rgba(255, 255, 255, 0.5);
}

.grammar-main {
  align-items: stretch;
}

.grammar-panel {
  width: 320px;
}

.grammar-visual {
  border: 1px solid #dbeafe;
  box-shadow: 0 10px 30px rgba(2, 6, 23, 0.08);
}

.grammar-tab-strip {
  background: linear-gradient(180deg, #ffffff, #f8fafc);
  border: 1px solid #e2e8f0;
  border-radius: 12px;
  padding: 8px;
}

.grammar-tab-btn {
  border: 1px solid #dbeafe !important;
  border-radius: 10px;
  background: #eff6ff !important;
  color: #0c4a6e !important;
  font-weight: 700;
}

.grammar-tab-btn.active {
  background: linear-gradient(90deg, #0284c7, #0f766e) !important;
  color: #fff !important;
  border-color: transparent !important;
}

.grammar-tab-panel h3 {
  color: #0f172a;
}

@media (max-width: 1024px) {
  .grammar-panel {
    width: calc(100% - 24px);
  }
}