/* ==========================================================================
   Grayscale Converter Online - Modern Dark Theme
   PicDriver Design System
   ========================================================================== */

:root {
  --primary-gray: #64748b;
  --primary-light: #94a3b8;
  --mono-accent: #38bdf8;
}

/* Tool Hero */
.tool-hero {
  text-align: center;
  padding: 48px 24px 32px;
  background: radial-gradient(circle at 50% 20%, rgba(100, 116, 139, 0.12) 0%, transparent 70%);
}

.tool-hero h1 {
  font-size: clamp(2rem, 4vw, 2.75rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  background: linear-gradient(135deg, #f8fafc 30%, #94a3b8 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  margin-bottom: 12px;
}

.tool-hero p {
  color: var(--text-secondary);
  max-width: 680px;
  margin: 0 auto;
  font-size: 1.05rem;
  line-height: 1.6;
}

/* Workspace Layout */
.tool-workspace {
  max-width: 1440px;
  margin: 0 auto;
  padding: 0 24px 60px;
}

.workspace-card {
  display: grid;
  grid-template-columns: 1fr 380px;
  gap: 24px;
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  overflow: hidden;
  box-shadow: 0 20px 40px -15px rgba(0, 0, 0, 0.5);
}

@media (max-width: 1024px) {
  .workspace-card {
    grid-template-columns: 1fr;
  }
}

/* Viewport Column */
.viewport-col {
  display: flex;
  flex-direction: column;
  background: #020617;
  position: relative;
  min-height: 600px;
  border-right: 1px solid var(--border-color);
  overflow: hidden;
}

@media (max-width: 1024px) {
  .viewport-col {
    border-right: none;
    border-bottom: 1px solid var(--border-color);
  }
}

/* Floating Toolbar */
.viewport-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 18px;
  background: rgba(15, 23, 42, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  z-index: 20;
}

.toolbar-group {
  display: flex;
  align-items: center;
  gap: 8px;
}

.tool-btn {
  background: var(--bg-surface-elevated);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 6px 12px;
  font-size: 0.82rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.15s ease;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.tool-btn:hover {
  background: var(--bg-surface-hover);
  border-color: var(--primary-light);
  color: #fff;
}

.tool-btn.active {
  background: rgba(56, 189, 248, 0.15);
  border-color: var(--mono-accent);
  color: var(--mono-accent);
}

.zoom-display {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--text-muted);
  min-width: 48px;
  text-align: center;
}

/* Canvas Viewport */
.canvas-container {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  overflow: hidden;
  padding: 24px;
  background-image: 
    linear-gradient(45deg, #090d16 25%, transparent 25%),
    linear-gradient(-45deg, #090d16 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, #090d16 75%),
    linear-gradient(-45deg, transparent 75%, #090d16 75%);
  background-size: 20px 20px;
  background-position: 0 0, 0 10px, 10px -10px, -10px 0px;
}

/* Zero Lag Canvas */
.grayscale-canvas {
  max-width: 100%;
  max-height: 100%;
  box-shadow: 0 10px 35px rgba(0, 0, 0, 0.65);
  border-radius: 4px;
  transform-origin: center center;
  transition: none !important;
  user-select: none;
  touch-action: none;
}

/* Before / After Wipe Overlay Bar */
.split-handle-line {
  position: absolute;
  top: 0;
  bottom: 0;
  width: 3px;
  background: #fff;
  box-shadow: 0 0 12px rgba(0,0,0,0.8);
  pointer-events: none;
  z-index: 10;
}

.split-handle-knob {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 32px;
  height: 32px;
  background: #fff;
  color: #0f172a;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  font-weight: 800;
  box-shadow: 0 2px 10px rgba(0,0,0,0.5);
  cursor: ew-resize;
  pointer-events: auto;
}

.split-label-left, .split-label-right {
  position: absolute;
  bottom: 20px;
  padding: 4px 10px;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  border-radius: 4px;
  background: rgba(15, 23, 42, 0.75);
  backdrop-filter: blur(6px);
  color: #fff;
  pointer-events: none;
  z-index: 10;
}

.split-label-left { left: 24px; }
.split-label-right { right: 24px; }

/* Controls Column */
.controls-col {
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 20px;
  max-height: 900px;
  overflow-y: auto;
  background: var(--bg-surface);
}

.controls-col::-webkit-scrollbar {
  width: 6px;
}
.controls-col::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: 3px;
}

.panel-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--border-color);
}

.panel-header h3 {
  font-size: 1.1rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  gap: 8px;
}

.sub-panel {
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 16px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.panel-section-title {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.84rem;
  font-weight: 700;
  color: var(--text-primary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.panel-icon-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 26px;
  height: 26px;
  background: rgba(100, 116, 139, 0.15);
  color: var(--primary-light);
  border-radius: 6px;
}

/* Film Stock Presets Grid */
.film-presets-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 8px;
}

.film-preset-btn {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 10px 8px;
  color: var(--text-secondary);
  font-size: 0.8rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.15s ease;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 4px;
  text-align: left;
}

.film-preset-btn:hover {
  background: var(--bg-surface-hover);
  border-color: var(--primary-light);
  color: var(--text-primary);
}

.film-preset-btn.active {
  background: rgba(100, 116, 139, 0.2);
  border-color: #f1f5f9;
  color: #fff;
  box-shadow: 0 0 0 1px #f1f5f9;
}

.film-preset-desc {
  font-size: 0.68rem;
  font-weight: 400;
  color: var(--text-muted);
}

/* Sliders & Inputs */
.control-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

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

.control-label {
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.control-value {
  font-size: 0.78rem;
  font-family: var(--font-mono);
  color: var(--text-muted);
}

.slider {
  width: 100%;
  height: 6px;
  background: #1e293b;
  border-radius: 3px;
  outline: none;
  accent-color: #94a3b8;
  cursor: pointer;
}

.select-input, .text-input {
  width: 100%;
  padding: 8px 12px;
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-size: 0.84rem;
  outline: none;
  transition: border-color 0.15s ease;
}

.select-input:focus, .text-input:focus {
  border-color: var(--mono-accent);
}

/* Channel Mixer Bar */
.channel-row {
  display: grid;
  grid-template-columns: 24px 1fr 44px;
  align-items: center;
  gap: 8px;
}

.channel-tag {
  font-size: 0.75rem;
  font-weight: 800;
  text-align: center;
  border-radius: 4px;
  padding: 2px 0;
}
.channel-tag.red { background: rgba(239, 68, 68, 0.2); color: #ef4444; }
.channel-tag.green { background: rgba(34, 197, 94, 0.2); color: #22c55e; }
.channel-tag.blue { background: rgba(59, 130, 246, 0.2); color: #3b82f6; }

/* Photo Queue Strip */
.queue-strip {
  display: flex;
  gap: 8px;
  overflow-x: auto;
  padding: 4px 2px;
}

.queue-strip::-webkit-scrollbar {
  height: 4px;
}
.queue-strip::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: 2px;
}

.queue-thumb-item {
  position: relative;
  width: 60px;
  height: 60px;
  border-radius: var(--radius-sm);
  overflow: hidden;
  border: 2px solid transparent;
  flex-shrink: 0;
  cursor: pointer;
  background: #020617;
}

.queue-thumb-item.active {
  border-color: #38bdf8;
}

.queue-thumb-item img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.queue-item-delete {
  position: absolute;
  top: 2px;
  right: 2px;
  width: 18px;
  height: 18px;
  background: rgba(0, 0, 0, 0.75);
  color: #ef4444;
  border: none;
  border-radius: 50%;
  font-size: 11px;
  line-height: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
}

/* Action Buttons */
.btn-primary {
  background: linear-gradient(135deg, #475569, #334155);
  color: #fff;
  border: 1px solid #64748b;
  border-radius: var(--radius-md);
  padding: 12px 18px;
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  transition: all 0.2s ease;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

.btn-primary:hover {
  background: linear-gradient(135deg, #64748b, #475569);
  border-color: #94a3b8;
  transform: translateY(-1px);
}

.btn-zip-export {
  background: transparent;
  color: var(--mono-accent);
  border: 1px solid rgba(56, 189, 248, 0.4);
  border-radius: var(--radius-md);
  padding: 10px 16px;
  font-weight: 600;
  font-size: 0.86rem;
  cursor: pointer;
  transition: all 0.15s ease;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
}

.btn-zip-export:hover {
  background: rgba(56, 189, 248, 0.12);
  border-color: var(--mono-accent);
}

.btn-subtle {
  background: transparent;
  border: none;
  color: var(--text-muted);
  font-size: 0.8rem;
  cursor: pointer;
  transition: color 0.15s ease;
}

.btn-subtle:hover {
  color: #ef4444;
}

/* Dropzone Styling */
.dropzone-container {
  padding: 40px 0;
}

.mono-uploader-box {
  background: var(--bg-surface);
  border: 2px dashed var(--border-color);
  border-radius: var(--radius-xl);
  padding: 60px 24px;
  text-align: center;
  transition: all 0.2s ease;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

.mono-uploader-box.drag-over {
  border-color: var(--mono-accent);
  background: rgba(56, 189, 248, 0.05);
}

.dropzone-icon {
  width: 64px;
  height: 64px;
  color: var(--primary-light);
  margin-bottom: 16px;
}

.dropzone-title {
  font-size: 1.4rem;
  font-weight: 700;
  margin-bottom: 6px;
}

.dropzone-subtitle {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin-bottom: 24px;
}

.btn-upload {
  background: linear-gradient(135deg, #475569, #334155);
  color: #fff;
  border: 1px solid #64748b;
  border-radius: var(--radius-md);
  padding: 12px 28px;
  font-weight: 600;
  font-size: 0.95rem;
  cursor: pointer;
  transition: all 0.2s ease;
}

.btn-upload:hover {
  background: linear-gradient(135deg, #64748b, #475569);
  transform: translateY(-1px);
}

.btn-sample-demo {
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  border-radius: var(--radius-sm);
  padding: 4px 10px;
  font-size: 0.78rem;
  cursor: pointer;
  transition: all 0.15s ease;
}

.btn-sample-demo:hover {
  background: var(--bg-surface-hover);
  color: #fff;
}

.paste-hint {
  font-size: 0.78rem;
  color: var(--text-muted);
}
.kbd {
  background: #1e293b;
  border: 1px solid #334155;
  border-radius: 4px;
  padding: 1px 5px;
  font-family: var(--font-mono);
  font-size: 0.74rem;
}