:root {
  --primary-color: hsl(220, 70%, 55%);
  --primary-hover: hsl(220, 70%, 60%);
  --accent-color: hsl(340, 80%, 60%);
  --bg-gradient-start: hsl(220, 25%, 10%);
  --bg-gradient-end: hsl(220, 20%, 16%);
  --card-bg: hsla(220, 25%, 20%, 0.6);
  --card-border: hsla(220, 25%, 40%, 0.3);
  --text-main: hsl(220, 10%, 95%);
  --text-muted: hsl(220, 10%, 70%);
  --canvas-bg: #808080;
  --danger-color: hsl(0, 70%, 55%);
  
  --radius-card: 12px;
  --radius-item: 8px;
  --font-main: 'Inter', system-ui, sans-serif;
  --transition-speed: 300ms;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--font-main);
  background: linear-gradient(135deg, var(--bg-gradient-start), var(--bg-gradient-end));
  background-attachment: fixed;
  color: var(--text-main);
  min-height: 100vh;
  display: flex;
  justify-content: center;
  padding: 2rem 1rem;
  line-height: 1.5;
}

#app {
  width: 100%;
  max-width: 800px;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

/* Header */
#appHeader {
  text-align: center;
  margin-bottom: 0.5rem;
}

h1 {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 0.25rem;
  background: linear-gradient(90deg, var(--text-main), var(--primary-color));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.subtitle {
  color: var(--text-muted);
  font-size: 1.1rem;
}

/* Glassmorphism Cards */
.card {
  background: var(--card-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-card);
  padding: 1.25rem;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.2);
  transition: opacity var(--transition-speed) ease, transform var(--transition-speed) ease;
}

.card[hidden] {
  display: none;
  opacity: 0;
  transform: translateY(10px);
}

/* Focus styles */
:focus-visible {
  outline: 2px solid var(--primary-color);
  outline-offset: 2px;
}

/* Buttons */
button {
  font-family: var(--font-main);
  border: none;
  border-radius: var(--radius-item);
  cursor: pointer;
  font-size: 1rem;
  font-weight: 600;
  transition: transform 0.2s ease, background-color 0.2s ease;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
}

button:active {
  transform: scale(0.98);
}

button:hover {
  transform: scale(1.02);
}

#selectImagesBtn {
  background-color: var(--primary-color);
  color: white;
  padding: 0.75rem 1.5rem;
  width: 100%;
  margin-top: 1rem;
}

#selectImagesBtn:hover {
  background-color: var(--primary-hover);
}

.secondary-btn {
  background-color: transparent;
  color: var(--text-main);
  border: 1px solid var(--card-border);
  padding: 0.5rem 1rem;
}

.secondary-btn:hover {
  background-color: hsla(220, 25%, 40%, 0.2);
}

/* Settings Layout */
.settings-layout {
  display: flex;
  gap: 2rem;
  align-items: center;
}

.diagram-container {
  flex: 0 0 250px;
  display: flex;
  justify-content: center;
  align-items: center;
}

.settings-inputs {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.inputs-row {
  display: flex;
  gap: 1rem;
}

.input-group {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

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

input[type="number"] {
  background: hsla(220, 20%, 10%, 0.5);
  border: 1px solid var(--card-border);
  color: var(--text-main);
  padding: 0.5rem 0.75rem;
  border-radius: var(--radius-item);
  font-family: var(--font-main);
  font-size: 1rem;
  transition: border-color 0.2s;
}

input[type="number"]:focus {
  outline: none;
  border-color: var(--primary-color);
}

.error-msg {
  color: var(--accent-color);
  font-size: 0.85rem;
  margin-top: 0.25rem;
}

.file-hint {
  font-size: 0.8rem;
  color: var(--text-muted);
  text-align: center;
}

/* Crop Section */
.empty-state {
  text-align: center;
  padding: 4rem 2rem;
  color: var(--text-muted);
}

.empty-icon {
  font-size: 4rem;
  margin-bottom: 1rem;
  opacity: 0.5;
}

.canvas-wrapper {
  position: relative;
  width: 100%;
  aspect-ratio: 1 / 1;
  max-width: 600px;
  margin: 0 auto;
  border-radius: var(--radius-item);
  overflow: hidden;
  box-shadow: inset 0 0 20px rgba(0,0,0,0.5);
}

#cropCanvas {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: var(--canvas-bg);
  cursor: grab;
  touch-action: none;
  display: block;
}

#cropCanvas:active {
  cursor: grabbing;
}

.bleed-tooltip {
  position: absolute;
  top: 1rem;
  left: 50%;
  transform: translateX(-50%);
  background: rgba(0, 0, 0, 0.8);
  color: white;
  padding: 0.5rem 1rem;
  border-radius: 20px;
  font-size: 0.85rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  pointer-events: auto;
  z-index: 10;
  backdrop-filter: blur(4px);
}

.bleed-tooltip[hidden] {
  display: none;
}

#bleedTooltipClose {
  background: none;
  border: none;
  color: var(--text-muted);
  padding: 0;
  margin: 0;
  font-size: 1rem;
  min-width: 20px;
}

#bleedTooltipClose:hover {
  color: white;
  transform: scale(1.1);
}

.crop-controls {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 1.5rem;
  flex-wrap: wrap;
  gap: 1rem;
}

.zoom-control {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex: 1;
  min-width: 250px;
}

.zoom-btn {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--card-border);
  color: var(--text-main);
  padding: 0;
}

.zoom-btn:hover {
  background: hsla(220, 25%, 50%, 0.5);
}

input[type="range"] {
  flex: 1;
  accent-color: var(--primary-color);
}

.zoom-label {
  font-variant-numeric: tabular-nums;
  min-width: 3rem;
  text-align: right;
  color: var(--text-muted);
}

/* Thumbnail Strip */
#thumbnailSection {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1rem;
}

.thumbnail-strip {
  display: flex;
  gap: 1rem;
  overflow-x: auto;
  padding-bottom: 0.5rem;
  flex: 1;
  scrollbar-width: thin;
  scrollbar-color: var(--card-border) transparent;
}

.thumbnail-strip::-webkit-scrollbar {
  height: 6px;
}

.thumbnail-strip::-webkit-scrollbar-thumb {
  background-color: var(--card-border);
  border-radius: 3px;
}

.thumb-item {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  min-width: 80px;
}

.thumb-btn {
  width: 80px;
  height: 80px;
  border-radius: var(--radius-item);
  padding: 0;
  overflow: hidden;
  border: 2px solid transparent;
  position: relative;
  background: var(--canvas-bg);
}

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

.thumb-btn.active {
  border-color: var(--primary-color);
}

.thumb-status {
  position: absolute;
  bottom: 4px;
  right: 4px;
  background: rgba(0,0,0,0.7);
  border-radius: 4px;
  padding: 2px 4px;
  font-size: 0.7rem;
}

.thumb-remove {
  position: absolute;
  top: -6px;
  right: -6px;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--danger-color);
  color: white;
  font-size: 12px;
  line-height: 1;
  padding: 0;
  z-index: 2;
  box-shadow: 0 2px 4px rgba(0,0,0,0.3);
}

.thumb-copies {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.thumb-copies input {
  width: 40px;
  padding: 0.25rem;
  text-align: center;
}

.add-more-btn {
  flex-shrink: 0;
  width: 80px;
  height: 80px;
  border: 2px dashed var(--card-border);
  background: transparent;
  color: var(--text-muted);
  flex-direction: column;
  font-size: 0.9rem;
  margin-bottom: auto; /* Align with thumbs, not inputs */
}

.add-more-btn:hover {
  border-color: var(--primary-color);
  color: var(--primary-color);
  background: hsla(220, 70%, 55%, 0.1);
}

/* Generate Section */
.generate-section {
  text-align: center;
  padding-bottom: 2rem;
  animation: fadeIn 0.3s ease;
}

#generatePdfBtn {
  background: linear-gradient(135deg, var(--primary-color), hsl(250, 70%, 60%));
  color: white;
  padding: 1rem 2rem;
  font-size: 1.25rem;
  border-radius: 50px;
  box-shadow: 0 4px 15px hsla(220, 70%, 55%, 0.4);
}

#generatePdfBtn:hover {
  box-shadow: 0 6px 20px hsla(220, 70%, 55%, 0.6);
}

.progress-container {
  margin-top: 1rem;
}

.progress-track {
  height: 6px;
  background: var(--card-border);
  border-radius: 3px;
  overflow: hidden;
  max-width: 300px;
  margin: 0 auto 0.5rem;
}

.progress-fill {
  height: 100%;
  background: var(--primary-color);
  width: 0%;
  transition: width 0.2s ease;
}

.completion-msg {
  margin-top: 1rem;
  color: hsl(120, 60%, 60%);
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.completion-msg a {
  color: var(--primary-color);
  text-decoration: underline;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Responsive tweaks */
@media (max-width: 600px) {
  .settings-layout {
    flex-direction: column;
  }
  .inputs-row {
    flex-direction: column;
    gap: 0.5rem;
  }
  .diagram-container {
    flex: 0 0 auto;
  }
  .crop-controls {
    flex-direction: column;
    align-items: stretch;
  }
  .zoom-control {
    margin-bottom: 1rem;
  }
}