/* Modern Design System & Variables */
:root {
  /* Branding Colors */
  --primary: #5e97cc;
  --primary-hover: #4880b5;
  --primary-light: rgba(94, 151, 204, 0.15);
  --secondary: #494292;
  --secondary-hover: #37307a;
  --secondary-light: rgba(73, 66, 146, 0.15);
  --success: #10b981;
  --success-light: rgba(16, 185, 129, 0.1);
  --error: #ef4444;

  /* Fonts */
  --font-sans: 'Lato', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;

  /* Light Theme Variables */
  --bg-color: #f3f7fa;
  --surface-color: #ffffff;
  --text-color: #1e293b;
  --text-muted: #64748b;
  --border-color: #e2e8f0;
  --shadow-sm: 0 4px 6px -1px rgba(73, 66, 146, 0.04), 0 2px 4px -1px rgba(73, 66, 146, 0.04);
  --shadow-md: 0 10px 20px -3px rgba(73, 66, 146, 0.06), 0 4px 6px -2px rgba(73, 66, 146, 0.05);
  --shadow-lg: 0 20px 25px -5px rgba(73, 66, 146, 0.08), 0 10px 10px -5px rgba(73, 66, 146, 0.04);
  --card-bg: rgba(255, 255, 255, 0.85);
  --glass-border: rgba(255, 255, 255, 0.6);
  --header-bg: rgba(255, 255, 255, 0.8);
}

/* Dark Theme Overrides */
.dark-mode {
  --bg-color: #0b0f19;
  --surface-color: #161e2e;
  --text-color: #f8fafc;
  --text-muted: #94a3b8;
  --border-color: #1e293b;
  --shadow-sm: 0 4px 6px -1px rgba(0, 0, 0, 0.2);
  --shadow-md: 0 10px 20px -3px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 20px 25px -5px rgba(0, 0, 0, 0.4);
  --card-bg: rgba(22, 30, 46, 0.8);
  --glass-border: rgba(30, 41, 59, 0.5);
  --header-bg: rgba(11, 15, 25, 0.8);
}

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-color);
  color: var(--text-color);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  transition: background-color 0.4s cubic-bezier(0.4, 0, 0.2, 1), 
              color 0.4s cubic-bezier(0.4, 0, 0.2, 1);
  overflow-x: hidden;
}

/* Google Fonts Import Link is in HTML */

/* Layout Containers */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* Header */
header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: var(--header-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  padding: 0.85rem 0;
  transition: background-color 0.4s, border-color 0.4s;
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
}

.brand-logo {
  height: 42px;
  width: 42px;
  object-fit: contain;
  transition: transform 0.3s ease;
}

.brand:hover .brand-logo {
  transform: rotate(5deg) scale(1.05);
}

.brand-text {
  display: flex;
  flex-direction: column;
}

.brand-name {
  font-size: 1.15rem;
  font-weight: 800;
  color: var(--secondary);
  letter-spacing: 0.5px;
  line-height: 1.2;
  transition: color 0.4s;
}

.dark-mode .brand-name {
  color: var(--primary);
}

.brand-tagline {
  font-size: 0.75rem;
  color: var(--text-muted);
  font-weight: 500;
}

/* Theme Toggle Button */
.theme-toggle-btn {
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-color);
  cursor: pointer;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.3s ease;
  background-color: var(--surface-color);
}

.theme-toggle-btn:hover {
  transform: scale(1.08);
  border-color: var(--primary);
  box-shadow: 0 0 10px var(--primary-light);
}

.theme-toggle-btn svg {
  width: 20px;
  height: 20px;
  fill: currentColor;
  transition: transform 0.5s ease;
}

/* Spin dark mode icon on click */
.theme-toggle-btn:active svg {
  transform: rotate(45deg);
}

/* Hero Section */
.hero {
  text-align: center;
  padding: 4rem 1.5rem 3rem 1.5rem;
}

.hero h1 {
  font-size: 2.75rem;
  font-weight: 900;
  color: var(--secondary);
  margin-bottom: 0.75rem;
  letter-spacing: -0.5px;
  transition: color 0.4s;
}

.dark-mode .hero h1 {
  color: var(--primary);
}

.hero p {
  font-size: 1.15rem;
  color: var(--text-muted);
  max-width: 600px;
  margin: 0 auto;
  font-weight: 400;
}

/* Main Workspace Grid (Desktop Side-by-Side) */
.workspace-grid {
  display: grid;
  grid-template-columns: 1fr 1.1fr;
  gap: 2rem;
  align-items: start;
  margin-bottom: 2rem;
}

/* Cards (Glassmorphism design) */
.card {
  background-color: var(--card-bg);
  border: 1px solid var(--glass-border);
  border-radius: 24px;
  padding: 2rem;
  box-shadow: var(--shadow-lg);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  transition: transform 0.3s ease, box-shadow 0.3s ease, background-color 0.4s, border-color 0.4s;
}

.card:hover {
  box-shadow: var(--shadow-lg), 0 15px 30px -10px var(--primary-light);
}

.card-title {
  font-size: 1.25rem;
  font-weight: 800;
  margin-bottom: 1.25rem;
  color: var(--secondary);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.dark-mode .card-title {
  color: var(--primary);
}

.card-title svg {
  width: 22px;
  height: 22px;
  stroke: currentColor;
  stroke-width: 2;
  fill: none;
}

/* Upload Container */
.upload-zone {
  border: 2.5px dashed var(--border-color);
  border-radius: 18px;
  padding: 3rem 1.5rem;
  text-align: center;
  cursor: pointer;
  background-color: rgba(94, 151, 204, 0.02);
  transition: all 0.3s ease;
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 250px;
}

.upload-zone:hover, .upload-zone.dragover {
  border-color: var(--primary);
  background-color: var(--primary-light);
  transform: scale(1.01);
}

.upload-zone.success {
  border-color: var(--success);
  background-color: var(--success-light);
}

.upload-icon {
  width: 56px;
  height: 56px;
  color: var(--primary);
  margin-bottom: 1.25rem;
  transition: transform 0.3s ease, color 0.3s ease;
}

.upload-zone:hover .upload-icon {
  transform: translateY(-5px);
}

.upload-zone.success .upload-icon {
  color: var(--success);
  transform: scale(1.1);
}

.upload-text {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.upload-subtext {
  font-size: 0.8rem;
  color: var(--text-muted);
}

.file-input {
  display: none;
}

/* Preview Card */
.preview-container {
  display: flex;
  justify-content: center;
  align-items: center;
  position: relative;
  width: 100%;
}

.canvas-wrapper {
  position: relative;
  width: 100%;
  aspect-ratio: 1 / 1;
  max-width: 500px;
  border-radius: 18px;
  overflow: hidden;
  box-shadow: var(--shadow-md);
  border: 1px solid var(--border-color);
  background-color: #ffffff;
  transition: border-color 0.4s;
}

.dark-mode .canvas-wrapper {
  background-color: #111827;
}

canvas {
  width: 100%;
  height: 100%;
  display: block;
  cursor: grab;
}

canvas:active {
  cursor: grabbing;
}

/* Status Indicator */
.status-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.4rem 1rem;
  border-radius: 50px;
  font-size: 0.85rem;
  font-weight: 700;
  margin-top: 1rem;
  transition: all 0.3s ease;
}

.status-badge.empty {
  background-color: var(--border-color);
  color: var(--text-muted);
}

.status-badge.ready {
  background-color: var(--success-light);
  color: var(--success);
  animation: pulse-badge 2s infinite;
}

@keyframes pulse-badge {
  0% { box-shadow: 0 0 0 0 rgba(16, 185, 129, 0.4); }
  70% { box-shadow: 0 0 0 8px rgba(16, 185, 129, 0); }
  100% { box-shadow: 0 0 0 0 rgba(16, 185, 129, 0); }
}

/* Controls Card & Subsections (Positioned below columns on desktop) */
.controls-card {
  grid-column: 1 / -1; /* spans full grid width */
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.controls-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
}

.control-group {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.control-label {
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--text-muted);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.control-val {
  font-family: monospace;
  font-size: 0.85rem;
  font-weight: bold;
  color: var(--primary);
}

/* Premium Range Sliders */
.slider {
  -webkit-appearance: none;
  width: 100%;
  height: 8px;
  border-radius: 99px;
  background: var(--border-color);
  outline: none;
  transition: background 0.3s;
}

.slider::-webkit-slider-runnable-track {
  width: 100%;
  height: 8px;
  cursor: pointer;
  border-radius: 99px;
}

.slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  height: 20px;
  width: 20px;
  border-radius: 50%;
  background: var(--primary);
  cursor: pointer;
  margin-top: -6px;
  box-shadow: 0 2px 5px rgba(0,0,0,0.15);
  transition: transform 0.1s ease, background 0.3s;
}

.slider:hover::-webkit-slider-thumb {
  transform: scale(1.15);
  background: var(--primary-hover);
}

.slider::-moz-range-track {
  width: 100%;
  height: 8px;
  cursor: pointer;
  border-radius: 99px;
  background: var(--border-color);
}

.slider::-moz-range-thumb {
  height: 20px;
  width: 20px;
  border-radius: 50%;
  background: var(--primary);
  cursor: pointer;
  border: none;
  box-shadow: 0 2px 5px rgba(0,0,0,0.15);
  transition: transform 0.1s ease, background 0.3s;
}

.slider:hover::-moz-range-thumb {
  transform: scale(1.15);
  background: var(--primary-hover);
}

/* Action Buttons */
.buttons-group {
  display: flex;
  gap: 1rem;
  justify-content: flex-end;
  margin-top: 0.5rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.6rem;
  font-family: var(--font-sans);
  font-size: 0.95rem;
  font-weight: 700;
  padding: 0.85rem 1.75rem;
  border-radius: 14px;
  cursor: pointer;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  border: none;
  box-shadow: var(--shadow-sm);
}

.btn svg {
  width: 18px;
  height: 18px;
  fill: none;
  stroke: currentColor;
  stroke-width: 2.2;
}

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

.btn-primary:hover:not(:disabled) {
  background-color: var(--secondary-hover);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md), 0 5px 15px var(--secondary-light);
}

.btn-accent {
  background-color: var(--primary);
  color: #ffffff;
}

.btn-accent:hover:not(:disabled) {
  background-color: var(--primary-hover);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md), 0 5px 15px var(--primary-light);
}

.btn-outline {
  background-color: transparent;
  color: var(--text-color);
  border: 1.5px solid var(--border-color);
  background-color: var(--surface-color);
}

.btn-outline:hover:not(:disabled) {
  border-color: var(--text-color);
  transform: translateY(-2px);
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none !important;
  box-shadow: none !important;
}

/* Footer */
footer {
  margin-top: auto;
  padding: 2.5rem 0;
  border-top: 1px solid var(--border-color);
  text-align: center;
  transition: border-color 0.4s;
}

.footer-text {
  font-size: 0.9rem;
  color: var(--text-muted);
  font-weight: 500;
}

/* Responsive Breakpoints */
@media (max-width: 900px) {
  .workspace-grid {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }
  
  .controls-card {
    grid-column: span 1;
  }
  
  .hero {
    padding: 3rem 1rem 2rem 1rem;
  }
  
  .hero h1 {
    font-size: 2.2rem;
  }
  
  .hero p {
    font-size: 1rem;
  }
}

@media (max-width: 600px) {
  .card {
    padding: 1.25rem;
    border-radius: 18px;
  }

  .controls-row {
    grid-template-columns: 1fr;
    gap: 1.25rem;
  }

  .buttons-group {
    flex-direction: column-reverse;
  }

  .btn {
    width: 100%;
  }

  .header-content {
    flex-direction: column;
    gap: 1rem;
    text-align: center;
  }
}