:root {
  --ink: #0b0c0f;
  --ink-2: #1c1e25;
  --ink-3: #2a2d38;
  --muted: #6b7080;
  --muted-2: #9499aa;
  --surface: #f5f4f0;
  --surface-2: #eceae4;
  --surface-3: #e2dfd7;
  --line: rgba(11,12,15,0.1);
  --accent: #3d4cff;
  --accent-dim: rgba(61,76,255,0.12);
  --accent-glow: rgba(61,76,255,0.06);
  --white: #fff;
  --radius: 16px;
  --radius-sm: 8px;
  --radius-pill: 100px;
  --mono: 'Space Mono', monospace;
  --sans: 'DM Sans', sans-serif;
}

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

html { 
  scroll-behavior: smooth; 
}

body {
  font-family: var(--sans);
  background: var(--surface);
  color: var(--ink);
  min-height: 100vh;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

/* Grain overlay */
body::after {
  content: '';
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 9999;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.035'/%3E%3C/svg%3E");
  background-size: 180px 180px;
  opacity: .55;
}

/* Layout */
.wrap {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 2rem;
}

/* Header */
header {
  padding: 2rem 0 1.5rem;
  border-bottom: 1px solid var(--line);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  flex-wrap: wrap;
}

.brand {
  display: flex;
  align-items: baseline;
  gap: 12px;
}

.brand-name {
  font-family: var(--mono);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--ink);
  letter-spacing: -0.03em;
}

.brand-name span {
  color: var(--accent);
}

.brand-tag {
  font-size: 0.72rem;
  font-weight: 500;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  background: var(--surface-2);
  border: 1px solid var(--line);
  padding: 3px 10px;
  border-radius: var(--radius-pill);
}

.header-meta {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.meta-item {
  font-size: 0.8rem;
  color: var(--muted);
  display: flex;
  align-items: center;
  gap: 6px;
}

.meta-item a {
  color: var(--ink);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.15s;
}

.meta-item a:hover { 
  color: var(--accent); 
}

.meta-dot {
  width: 3px;
  height: 3px;
  border-radius: 50%;
  background: var(--muted-2);
}

/* Hero section */
.hero {
  padding: 4rem 0 3rem;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  align-items: center;
}

.hero-text h2 {
  font-size: clamp(2rem, 4vw, 3.2rem);
  font-weight: 300;
  line-height: 1.15;
  letter-spacing: -0.03em;
  color: var(--ink);
  margin-bottom: 1rem;
}

.hero-text h2 em {
  font-style: italic;
  font-weight: 300;
  color: var(--accent);
}

.hero-text p {
  font-size: 0.95rem;
  color: var(--muted);
  line-height: 1.7;
  max-width: 380px;
}

.hero-stats {
  display: flex;
  gap: 2rem;
  margin-top: 2.5rem;
  padding-top: 2rem;
  border-top: 1px solid var(--line);
}

.stat-val {
  font-family: var(--mono);
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--ink);
  letter-spacing: -0.04em;
}

.stat-label {
  font-size: 0.72rem;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-top: 2px;
}

/* Upload zone */
.upload-zone {
  border: 1.5px dashed var(--surface-3);
  border-radius: var(--radius);
  padding: 2.5rem 2rem;
  text-align: center;
  cursor: pointer;
  transition: border-color 0.2s, background 0.2s;
  position: relative;
  overflow: hidden;
  background: var(--white);
}

.upload-zone::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse at center, var(--accent-glow) 0%, transparent 70%);
  opacity: 0;
  transition: opacity 0.3s;
  pointer-events: none;
}

.upload-zone:hover::before,
.upload-zone.drag-over::before { 
  opacity: 1; 
}

.upload-zone:hover,
.upload-zone.drag-over {
  border-color: var(--accent);
  border-style: solid;
}

.upload-zone.has-image {
  border-style: solid;
  border-color: var(--line);
  padding: 0;
}

.upload-icon-wrap {
  width: 56px;
  height: 56px;
  border-radius: var(--radius-sm);
  background: var(--surface);
  border: 1px solid var(--line);
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 1rem;
  transition: transform 0.2s, background 0.2s;
}

.upload-zone:hover .upload-icon-wrap {
  transform: translateY(-2px);
  background: var(--accent-dim);
}

.upload-icon-wrap svg {
  width: 24px;
  height: 24px;
  color: var(--muted);
  transition: color 0.2s;
}

.upload-zone:hover .upload-icon-wrap svg { 
  color: var(--accent); 
}

.upload-title {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--ink);
  margin-bottom: 4px;
}

.upload-sub {
  font-size: 0.78rem;
  color: var(--muted-2);
}

.upload-sub kbd {
  font-family: var(--mono);
  font-size: 0.7rem;
  background: var(--surface-2);
  border: 1px solid var(--line);
  border-radius: 4px;
  padding: 1px 5px;
  color: var(--muted);
}

#preview {
  width: 100%;
  max-height: 280px;
  object-fit: contain;
  border-radius: var(--radius);
  display: none;
}

#fileInput { 
  display: none; 
}

/* Main workspace */
.workspace {
  padding: 3rem 0 4rem;
  border-top: 1px solid var(--line);
}

.workspace-layout {
  display: grid;
  grid-template-columns: 1fr 320px;
  gap: 3rem;
  align-items: start;
}

/* Controls panel */
.panel {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  position: sticky;
  top: 2rem;
}

.panel-header {
  padding: 1.25rem 1.5rem;
  border-bottom: 1px solid var(--line);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.panel-title {
  font-size: 0.78rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--muted);
}

.panel-body { 
  padding: 1.5rem; 
}

.field {
  margin-bottom: 1.25rem;
}

.field label {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--ink-3);
  margin-bottom: 8px;
}

.field label span {
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--accent);
  background: var(--accent-dim);
  padding: 2px 8px;
  border-radius: var(--radius-pill);
}

.stepper {
  display: flex;
  align-items: center;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  overflow: hidden;
  background: var(--surface);
}

.stepper button {
  width: 40px;
  height: 40px;
  border: none;
  background: transparent;
  cursor: pointer;
  font-size: 1.1rem;
  color: var(--muted);
  transition: background 0.15s, color 0.15s;
  flex-shrink: 0;
}

.stepper button:hover {
  background: var(--surface-2);
  color: var(--ink);
}

.stepper input {
  flex: 1;
  height: 40px;
  border: none;
  background: transparent;
  text-align: center;
  font-family: var(--mono);
  font-size: 1rem;
  font-weight: 700;
  color: var(--ink);
  outline: none;
  -moz-appearance: textfield;
}

.stepper input::-webkit-outer-spin-button,
.stepper input::-webkit-inner-spin-button { 
  -webkit-appearance: none; 
}

.grid-preview {
  display: grid;
  gap: 3px;
  margin: 1.25rem 0;
  height: 72px;
}

.grid-cell {
  background: var(--accent-dim);
  border-radius: 3px;
  border: 1px solid rgba(61,76,255,0.2);
  transition: background 0.3s;
  animation: gridCellFade 0.3s ease both;
}

@keyframes gridCellFade {
  from {
    opacity: 0;
    transform: scale(0.9);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}

.btn-split {
  width: 100%;
  padding: 0.85rem;
  background: var(--accent);
  color: white;
  border: none;
  border-radius: var(--radius-sm);
  font-family: var(--sans);
  font-size: 0.9rem;
  font-weight: 500;
  cursor: pointer;
  letter-spacing: -0.01em;
  transition: background 0.15s, transform 0.1s, opacity 0.2s;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
}

.btn-split:hover:not(:disabled) { 
  background: #2836ff; 
}

.btn-split:active:not(:disabled) { 
  transform: scale(0.98); 
}

.btn-split:disabled { 
  opacity: 0.45; 
  cursor: not-allowed; 
}

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

.hint-text {
  font-size: 0.72rem;
  color: var(--muted-2);
  text-align: center;
  margin-top: 12px;
  line-height: 1.5;
}

/* Results area */
.results-area { 
  min-height: 200px; 
}

.results-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.5rem;
}

.results-title {
  font-size: 1.1rem;
  font-weight: 500;
  letter-spacing: -0.02em;
}

.results-count {
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--muted);
  background: var(--surface-2);
  border: 1px solid var(--line);
  padding: 4px 12px;
  border-radius: var(--radius-pill);
}

.btn-dl-all {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 16px;
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius-pill);
  font-family: var(--sans);
  font-size: 0.78rem;
  font-weight: 500;
  color: var(--ink);
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s;
}

.btn-dl-all:hover {
  border-color: var(--accent);
  background: var(--accent-dim);
  color: var(--accent);
}

.pieces-grid {
  display: grid;
  gap: 6px;
}

.piece-item {
  position: relative;
  border-radius: var(--radius-sm);
  overflow: hidden;
  cursor: pointer;
  background: var(--white);
  border: 1px solid var(--line);
  aspect-ratio: 1;
  transition: transform 0.15s, box-shadow 0.15s;
}

.piece-item:hover { 
  transform: scale(1.03); 
  box-shadow: 0 8px 24px rgba(0,0,0,0.1); 
}

.piece-item img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.piece-overlay {
  position: absolute;
  inset: 0;
  background: rgba(61,76,255,0.85);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 4px;
  opacity: 0;
  transition: opacity 0.2s;
}

.piece-item:hover .piece-overlay { 
  opacity: 1; 
}

.piece-overlay svg { 
  width: 20px; 
  height: 20px; 
  color: white; 
}

.piece-overlay span {
  font-size: 0.7rem;
  font-weight: 500;
  color: rgba(255,255,255,0.8);
  font-family: var(--mono);
}

.piece-badge {
  position: absolute;
  bottom: 6px;
  left: 6px;
  font-family: var(--mono);
  font-size: 0.6rem;
  background: rgba(0,0,0,0.5);
  color: white;
  padding: 2px 6px;
  border-radius: 4px;
  backdrop-filter: blur(4px);
}

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

.empty-state svg {
  width: 48px;
  height: 48px;
  margin: 0 auto 1rem;
  opacity: 0.3;
}

.empty-state p { 
  font-size: 0.88rem; 
}

/* Toast notification */
.toast {
  position: fixed;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%) translateY(120%);
  background: var(--ink);
  color: white;
  padding: 0.6rem 1.25rem;
  border-radius: var(--radius-pill);
  font-size: 0.82rem;
  font-weight: 500;
  z-index: 9998;
  transition: transform 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
  max-width: 90vw;
  white-space: normal;
  text-align: center;
  pointer-events: none;
}

.toast.show { 
  transform: translateX(-50%) translateY(0); 
}

/* Footer */
footer {
  border-top: 1px solid var(--line);
  padding: 2rem 0;
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
}

.footer-copy {
  font-family: var(--mono);
  font-size: 0.7rem;
  color: var(--muted-2);
}

.footer-links {
  display: flex;
  gap: 1.5rem;
}

.footer-links a {
  font-size: 0.75rem;
  color: var(--muted);
  text-decoration: none;
  transition: color 0.15s;
}

.footer-links a:hover { 
  color: var(--accent); 
}

/* Animations */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(16px); }
  to   { opacity: 1; transform: translateY(0); }
}

.anim-1 { animation: fadeUp 0.4s ease both; }
.anim-2 { animation: fadeUp 0.4s 0.08s ease both; }
.anim-3 { animation: fadeUp 0.4s 0.16s ease both; }

.piece-item {
  animation: fadeUp 0.3s ease both;
}

/* Responsive */
@media (max-width: 900px) {
  .hero { 
    grid-template-columns: 1fr; 
    gap: 2.5rem; 
  }
  .workspace-layout { 
    grid-template-columns: 1fr; 
    gap: 2rem; 
  }
  .panel { 
    position: static; 
  }
  .hero-text h2 { 
    font-size: 2rem; 
  }
}

@media (max-width: 600px) {
  .wrap { 
    padding: 0 1.25rem; 
  }
  .header-meta { 
    display: none; 
  }
  .hero { 
    padding: 2.5rem 0 2rem; 
  }
  .hero-stats { 
    gap: 1.5rem; 
  }
  .toast { 
    white-space: normal; 
    max-width: 85vw; 
  }
}