/* -------------------------------------------------------------
 * EZ-Stitch: Professional 3-Panel Photo Merger CSS Design System
 * Modern Dark Mode, Glassmorphism, and Fluent Micro-interactions
 * ------------------------------------------------------------- */

:root {
  /* Color Palette */
  --bg-primary: #0a0e17;
  --bg-secondary: #121824;
  --bg-tertiary: #1b2336;
  --bg-card: rgba(20, 28, 45, 0.7);
  --bg-input: #0e1320;
  
  --border-color: rgba(255, 255, 255, 0.08);
  --border-focus: #3b82f6;
  --border-hover: rgba(255, 255, 255, 0.15);
  
  --accent-color: #3b82f6;
  --accent-gradient: linear-gradient(135deg, #3b82f6 0%, #6366f1 100%);
  --accent-glow: rgba(59, 130, 246, 0.3);
  
  --text-primary: #f3f4f6;
  --text-secondary: #9ca3af;
  --text-muted: #6b7280;
  --text-success: #10b981;
  --text-danger: #ef4444;
  
  /* Layout Constants */
  --sidebar-width: 380px;
  --header-height: 70px;
  --border-radius-lg: 16px;
  --border-radius-md: 10px;
  --border-radius-sm: 6px;
  
  /* Fonts */
  --font-display: 'Outfit', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-sans: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  
  /* Transitions */
  --transition-fast: 0.15s ease;
  --transition-normal: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Base resets & scrollbars */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  background-color: var(--bg-primary);
  color: var(--text-primary);
  font-family: var(--font-sans);
  min-height: 100vh;
  overflow-x: hidden;
  display: flex;
  flex-direction: column;
}

/* Custom Scrollbar */
::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}
::-webkit-scrollbar-track {
  background: var(--bg-primary);
}
::-webkit-scrollbar-thumb {
  background: var(--bg-tertiary);
  border-radius: 4px;
}
::-webkit-scrollbar-thumb:hover {
  background: var(--text-muted);
}

/* Main Layout Structure */
.app-container {
  display: flex;
  flex-direction: column;
  height: 100vh;
  min-height: 600px;
}

/* Header Styling */
.app-header {
  height: var(--header-height);
  background-color: rgba(10, 14, 23, 0.8);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  padding: 0 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  z-index: 100;
}

.logo-area {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.logo-icon {
  width: 28px;
  height: 28px;
  color: var(--border-focus);
}

.logo-text {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.5rem;
  letter-spacing: -0.02em;
}

.logo-highlight {
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.app-tagline {
  font-family: var(--font-display);
  font-size: 0.95rem;
  color: var(--text-secondary);
  font-weight: 400;
  display: none;
}

@media (min-width: 768px) {
  .app-tagline {
    display: block;
  }
}

.privacy-badge {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  background-color: rgba(16, 185, 129, 0.1);
  border: 1px solid rgba(16, 185, 129, 0.2);
  color: var(--text-success);
  padding: 0.4rem 0.8rem;
  border-radius: 50px;
  font-size: 0.75rem;
  font-weight: 600;
}

.privacy-badge svg {
  width: 14px;
  height: 14px;
}

/* Workspace Layout */
.app-workspace {
  display: flex;
  flex: 1;
  overflow: hidden;
  height: calc(100vh - var(--header-height));
  position: relative;
}

@media (max-width: 1024px) {
  .app-workspace {
    flex-direction: column;
    overflow-y: auto;
    height: auto;
  }
}

/* Sidebar / Controls Styling */
.controls-panel {
  width: var(--sidebar-width);
  background-color: var(--bg-secondary);
  border-right: 1px solid var(--border-color);
  padding: 1.5rem;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  flex-shrink: 0;
  box-shadow: 10px 0 30px rgba(0, 0, 0, 0.15);
}

@media (max-width: 1024px) {
  .controls-panel {
    width: 100%;
    border-right: none;
    border-bottom: 1px solid var(--border-color);
    overflow-y: visible;
  }
}

.panel-section {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-lg);
  padding: 1.25rem;
  backdrop-filter: blur(10px);
}

.panel-section h2 {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 1rem;
  color: var(--text-primary);
  letter-spacing: -0.01em;
  border-left: 3px solid var(--border-focus);
  padding-left: 0.6rem;
}

/* Input Fields and Selects */
.control-group {
  margin-bottom: 1.25rem;
}

.control-group:last-child {
  margin-bottom: 0;
}

.control-group label {
  display: block;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-secondary);
  margin-bottom: 0.5rem;
}

.form-select, .form-input {
  width: 100%;
  background-color: var(--bg-input);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-md);
  color: var(--text-primary);
  padding: 0.75rem 1rem;
  font-size: 0.9rem;
  font-family: var(--font-sans);
  outline: none;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.form-select {
  cursor: pointer;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%239ca3af' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 1rem center;
  background-size: 16px;
  padding-right: 2.5rem;
}

.form-select:focus, .form-input:focus {
  border-color: var(--border-focus);
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.2);
}

.control-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
}

.custom-dims-row, .custom-ratios-row {
  margin-top: 0.75rem;
  background: rgba(0, 0, 0, 0.15);
  padding: 0.75rem;
  border-radius: var(--border-radius-md);
  border: 1px solid rgba(255, 255, 255, 0.04);
}

.custom-ratios-row {
  grid-template-columns: 1fr 1fr 1fr;
}

.hidden {
  display: none !important;
}

/* Color Picker Customization */
.color-picker-container {
  display: flex;
  gap: 0.5rem;
}

.color-picker-container input[type="color"] {
  width: 45px;
  height: 42px;
  border: 1px solid var(--border-color);
  background: none;
  border-radius: var(--border-radius-md);
  cursor: pointer;
  padding: 2px;
}

.color-picker-container input[type="color"]::-webkit-color-swatch {
  border-radius: 6px;
  border: none;
}

.color-text {
  font-family: monospace;
}

/* Range Inputs */
.range-container {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.form-range {
  flex: 1;
  height: 5px;
  background: var(--bg-input);
  border-radius: 5px;
  outline: none;
  cursor: pointer;
  appearance: none;
}

.form-range::-webkit-slider-thumb {
  appearance: none;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--border-focus);
  cursor: pointer;
  transition: transform var(--transition-fast);
}

.form-range::-webkit-slider-thumb:hover {
  transform: scale(1.2);
}

.range-val {
  font-size: 0.85rem;
  font-family: monospace;
  color: var(--text-secondary);
  min-width: 40px;
  text-align: right;
}

/* Button Stylings */
.btn {
  width: 100%;
  padding: 0.85rem 1.25rem;
  font-family: var(--font-display);
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: var(--border-radius-md);
  border: none;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  transition: all var(--transition-normal);
}

.btn svg {
  width: 18px;
  height: 18px;
}

.btn-primary {
  background: var(--accent-gradient);
  color: white;
  box-shadow: 0 4px 15px rgba(99, 102, 241, 0.2);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(99, 102, 241, 0.35);
  filter: brightness(1.1);
}

.btn-primary:active {
  transform: translateY(0);
}

.btn-secondary {
  background-color: transparent;
  color: var(--text-secondary);
  border: 1px solid var(--border-color);
}

.btn-secondary:hover {
  background-color: var(--bg-tertiary);
  color: var(--text-primary);
  border-color: var(--border-hover);
}

.action-buttons {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  margin-top: auto;
}

/* Preview Area (Right Pane) */
.preview-area {
  flex: 1;
  background-color: var(--bg-primary);
  background-image: radial-gradient(circle at 50% 50%, rgba(18, 24, 36, 0.8) 0%, rgba(10, 14, 23, 1) 100%);
  display: flex;
  flex-direction: column;
  padding: 2rem;
  overflow: auto;
  align-items: center;
  justify-content: center;
  gap: 1.5rem;
}

@media (max-width: 1024px) {
  .preview-area {
    padding: 1.5rem;
    overflow: visible;
  }
}

.preview-container-wrapper {
  width: 100%;
  max-width: 1000px;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.workspace-hint {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.8rem;
  color: var(--text-secondary);
  align-self: flex-start;
}

.workspace-hint svg {
  width: 16px;
  height: 16px;
  color: var(--border-focus);
}

/* Stitching Container Grid */
.stitch-preview-container {
  display: flex;
  width: 100%;
  aspect-ratio: 3 / 1;
  background-color: #ffffff; /* Default background of output image */
  border-radius: var(--border-radius-lg);
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.4);
  overflow: hidden;
  border: 1px solid var(--border-color);
  position: relative;
  transition: gap var(--transition-normal), background-color var(--transition-normal);
}

/* Individual Slot Layout */
.preview-slot {
  flex: 1;
  height: 100%;
  position: relative;
  background-color: var(--bg-tertiary);
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  user-select: none;
  transition: background-color var(--transition-normal), box-shadow var(--transition-fast);
}

.preview-slot:hover {
  background-color: #232d45;
}

/* Highlighting slots on dragover */
.preview-slot.drag-over {
  background-color: rgba(59, 130, 246, 0.15);
  box-shadow: inset 0 0 0 3px var(--border-focus);
}

.preview-slot.drag-over .placeholder-icon {
  color: var(--border-focus);
  transform: scale(1.1);
}

/* Placeholder inside slots */
.upload-placeholder {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 1.5rem;
  color: var(--text-secondary);
  pointer-events: none;
  transition: transform var(--transition-normal);
  z-index: 2;
}

.placeholder-icon {
  width: 48px;
  height: 48px;
  color: var(--text-muted);
  margin-bottom: 1rem;
  transition: all var(--transition-normal);
}

.placeholder-title {
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.25rem;
}

.placeholder-subtitle {
  font-size: 0.8rem;
  margin-bottom: 0.5rem;
}

.placeholder-desc {
  font-size: 0.7rem;
  color: var(--text-muted);
  background-color: rgba(0, 0, 0, 0.2);
  padding: 0.25rem 0.5rem;
  border-radius: 4px;
}

/* Image styling in slots */
.image-wrapper {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  z-index: 1;
}

.slot-image {
  position: absolute;
  transform-origin: center center;
  max-width: none;
  max-height: none;
  display: block;
  user-select: none;
  -webkit-user-drag: none;
}

/* Overlay controls on loaded slot */
.slot-overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(to bottom, rgba(10, 14, 23, 0.4) 0%, rgba(10, 14, 23, 0) 40%, rgba(10, 14, 23, 0.6) 100%);
  opacity: 0;
  transition: opacity var(--transition-normal);
  z-index: 10;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  padding: 0.75rem;
  pointer-events: none; /* Let clicks pass to dragging unless they hit buttons */
}

.preview-slot:hover .slot-overlay {
  opacity: 1;
}

.slot-title-badge {
  background-color: rgba(10, 14, 23, 0.85);
  border: 1px solid var(--border-color);
  backdrop-filter: blur(8px);
  color: var(--text-primary);
  padding: 0.35rem 0.65rem;
  border-radius: 50px;
  font-size: 0.75rem;
  font-weight: 600;
  align-self: flex-start;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.slot-controls {
  display: flex;
  gap: 0.4rem;
  justify-content: center;
  pointer-events: auto; /* Enable clicks on controls */
  align-self: center;
  background-color: rgba(10, 14, 23, 0.85);
  border: 1px solid var(--border-color);
  backdrop-filter: blur(8px);
  padding: 0.4rem;
  border-radius: 50px;
  box-shadow: 0 8px 16px rgba(0, 0, 0, 0.2);
  transform: translateY(10px);
  transition: transform var(--transition-normal);
}

.preview-slot:hover .slot-controls {
  transform: translateY(0);
}

.slot-btn {
  background: none;
  border: none;
  color: var(--text-secondary);
  width: 30px;
  height: 30px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.slot-btn:hover {
  background-color: var(--bg-tertiary);
  color: var(--text-primary);
}

.slot-btn.btn-remove:hover {
  background-color: rgba(239, 68, 68, 0.15);
  color: var(--text-danger);
}

.slot-btn svg {
  width: 16px;
  height: 16px;
}

/* File Input */
.file-input {
  display: none;
}

/* Guide Section */
.guide-card {
  width: 100%;
  max-width: 1000px;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-lg);
  padding: 1.5rem;
  margin-top: 1.5rem;
}

.guide-card h3 {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 1rem;
}

.guide-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.25rem;
}

@media (min-width: 768px) {
  .guide-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (min-width: 1200px) {
  .guide-grid {
    grid-template-columns: 1fr 1fr 1fr 1fr;
  }
}

.guide-item {
  display: flex;
  gap: 0.75rem;
}

.guide-num {
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background-color: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  color: var(--border-focus);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.8rem;
  font-weight: 700;
  flex-shrink: 0;
}

.guide-item strong {
  display: block;
  font-size: 0.85rem;
  color: var(--text-primary);
  margin-bottom: 0.2rem;
}

.guide-item p {
  font-size: 0.75rem;
  color: var(--text-secondary);
  line-height: 1.4;
}

/* Draggable mouse helper style */
.preview-slot.has-image {
  cursor: grab;
}

.preview-slot.has-image:active {
  cursor: grabbing;
}

/* Spinner Animation */
@keyframes spin {
  from {
    transform: rotate(0deg);
  }
  to {
    transform: rotate(360deg);
  }
}

.animate-spin {
  animation: spin 1s linear infinite;
}