:root {
  --primary-color: #141414;
  --primary-dark: #C90000;
  --secondary-color: #757575;
  --background-color: #f8f8f8;
  --panel-background: #ffffff;
  --text-color: #333333;
  --border-radius: 6px;
  --spacing-unit: 16px;
  --shadow: 0 1px 2px rgba(0,0,0,0.1);
}

body {
  font-family: 'Inter', 'Helvetica', -apple-system, BlinkMacSystemFont, sans-serif;
  background-color: var(--background-color);
  color: var(--text-color);
  margin: 0;
  padding: 0;
  min-height: 100vh;
}

a:link, a { color: var(--secondary-color);}
a:hover { color:var(--primary-dark); }

header, footer {
  padding: var(--spacing-unit);
  background-color: var(--panel-background);
  box-shadow: var(--shadow);
  margin: 0;
}

footer {
  position: relative;
  bottom: 0px;
  right: 0px;
  left:0px;
  z-index: 100;
}
footer p { font-size:13px; font-weight:normal; }

/* Floating Dark Mode Toggle Button */
.dark-mode-toggle {
  position: absolute;
  bottom: 20px;
  right: 20px;
  z-index: 1000;
}

header h1 {
  margin: 0;
  text-align: left;
  letter-spacing:-0.9px;
}


.app-container {
  max-width: 100%;
  margin: 0 auto;
  padding: var(--spacing-unit);
}

.container {
  display: flex;
  gap: calc(var(--spacing-unit) * 2);
}

/* Sidebar Styles */
.sidebar {
  width: 420px;
  flex-shrink: 0;
}

.panel {
  background: var(--panel-background);
  border-radius: var(--border-radius);
  padding: var(--spacing-unit);
  margin-bottom: var(--spacing-unit);
  box-shadow: var(--shadow);
}

.panel h3 {
  font-size: 16px;
  text-transform: uppercase;
  color: var(--secondary-color);
  margin: calc(var(--spacing-unit) * 1.5) 0 var(--spacing-unit) 0;
  letter-spacing: 0px;
}

/* Upload Area Styles */
.upload-area {
  border: 2px dashed #e0e0e0;
  border-radius: var(--border-radius);
  padding: calc(var(--spacing-unit) * 1.5);
  text-align: center;
  transition: all 0.3s ease;
}

.upload-area:hover {
  border-color: var(--primary-color);
  background-color: rgba(33, 150, 243, 0.05);
}

.upload-label {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  cursor: pointer;
  color: var(--secondary-color);
}

.upload-icon {
  font-size: 24px;
}

.upload-input {
  display: none;
}

/* Control Groups */
.control-group {
  margin-bottom: var(--spacing-unit);
}

.control-group label {
  display: block;
  margin-bottom: 8px;
  font-weight: 400;
  font-size: 13px;
}

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

input[type="range"] {
  flex: 1;
  height: 4px;
  -webkit-appearance: none;
  background: #e0e0e0;
  border-radius: 2px;
  outline: none;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 16px;
  height: 16px;
  background: var(--secondary-color);
  border-radius: 50%;
  cursor: pointer;
  box-shadow: var(--shadow);
  transition: all 0.2s ease;
}

input[type="range"]::-webkit-slider-thumb:hover {
  transform: scale(1.1);
}

.value-display {
  min-width: 40px;
  text-align: right;
  font-size: 14px;
  color: var(--secondary-color);
}

/* Select Styles */
.dither-select {
  width: 100%;
  padding: 8px 12px;
  border: 1px solid #e0e0e0;
  border-radius: 4px;
  background-color: white;
  font-size: 14px;
  color: var(--text-color);
  cursor: pointer;
}

/* Button Styles */
.action-panel {
  display: flex;
  gap: var(--spacing-unit);
}

.btn {
  flex: 1;
  padding: 12px 24px;
  border: none;
  border-radius: 4px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
}

.btn-primary {
  background-color: var(--primary-color);
  color: white;
}

.btn-primary:hover {
  background-color: var(--primary-dark);
}

.btn-secondary {
  background-color: #f5f5f5;
  color: var(--secondary-color);
}

.btn-secondary:hover {
  background-color: #e0e0e0;
}

/* Main Content Area */
.main-content {
  flex: 1;
  min-height: 600px;
  background: var(--panel-background);
  border-radius: var(--border-radius);
  box-shadow: var(--shadow);
  overflow: hidden;
}

.canvas-container {
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  background: #fff;
  padding: var(--spacing-unit);
  box-sizing: border-box;
}

canvas {
  max-width: 100%;
  max-height: 100%;
  object-fit: contain;
}

.action-panel { margin-bottom:var(--spacing-unit);}

/* Responsive Design */
@media (max-width: 1024px) {
  .container {
    flex-direction: column;
  }
  .sidebar {
    width: 100%;
  }
  .main-content {
    min-height: 400px;
  }
}

/* Dark Mode Styles */
body.dark-mode {
  --background-color: #121212;
  --panel-background: #1e1e1e;
  --text-color: #ffffff;
  --secondary-color: #bbbbbb;
}

body.dark-mode .upload-area {
  border-color: #333;
}

body.dark-mode .upload-area:hover {
  background-color: rgba(255, 255, 255, 0.05);
}

body.dark-mode .upload-label {
  color: var(--secondary-color);
}

body.dark-mode .value-display {
  color: var(--secondary-color);
}

body.dark-mode .dither-select {
  background-color: #333;
  color: #ffffff;
}
body.dark-mode .btn-primary {
  background-color: #777;
    color: white;
}
body.dark-mode .btn-primary:hover { background-color: var(--primary-dark); }
body.dark-mode .btn-secondary {
  background-color: #444;
  color: #ffffff;
}

body.dark-mode .btn-secondary:hover {
  background-color: #555;
}

body.dark-mode .canvas-container {
  background: #1e1e1e;
}