* { box-sizing: border-box; }
:root {
  --bg: #fafbfc;
  --panel: #ffffff;
  --border: #e1e5e9;
  --border-hover: #c1c8cd;
  --text: #1c2025;
  --text-secondary: #636b74;
  --accent: #0969da;
  --accent-hover: #0860ca;
  --success: #1a7f37;
  --danger: #d1242f;
  --shadow: 0 1px 3px rgba(16, 24, 40, 0.1), 0 1px 2px rgba(16, 24, 40, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(16, 24, 40, 0.1), 0 4px 6px -2px rgba(16, 24, 40, 0.05);
  --radius: 8px;
  --radius-lg: 12px;
}
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans", Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
  font-size: 14px;
}
header {
  padding: 24px;
  background: var(--panel);
  border-bottom: 1px solid var(--border);
  box-shadow: var(--shadow);
}
header h1 { 
  margin: 0 0 8px; 
  font-size: 24px; 
  font-weight: 600;
  letter-spacing: -0.025em;
}
header p { 
  margin: 0; 
  color: var(--text-secondary); 
  font-size: 15px;
}

main {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  padding: 24px;
  max-width: 1400px;
  margin: 0 auto;
}

.controls {
  background: var(--panel);
  padding: 24px;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
  height: fit-content;
}

.field { 
  display: flex; 
  flex-direction: column; 
  gap: 8px; 
  margin-bottom: 20px; 
}
.field label { 
  color: var(--text); 
  font-size: 13px; 
  font-weight: 500;
  letter-spacing: 0.01em;
}
.field input[type="text"],
.field input[type="number"],
.field input[type="color"] {
  background: var(--panel);
  color: var(--text);
  border: 1px solid var(--border);
  padding: 10px 12px;
  border-radius: var(--radius);
  font-size: 14px;
  transition: all 0.2s ease;
}
.field input[type="text"]:focus,
.field input[type="number"]:focus,
.field input[type="color"]:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(9, 105, 218, 0.1);
}
.field input[type="file"] { 
  font-size: 13px;
  padding: 8px 0;
}
.field input[type="color"] {
  width: 60px;
  height: 40px;
  padding: 4px;
  cursor: pointer;
}
.field.checkbox { 
  flex-direction: row;
  align-items: center;
  gap: 8px;
}
.field.checkbox input[type="checkbox"] {
  margin: 0;
}

.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.grid-3 { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 16px; align-items: end; }

.actions { display: flex; gap: 12px; margin-top: 8px; }
button {
  background: var(--accent);
  color: white;
  padding: 12px 20px;
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  font-weight: 500;
  font-size: 14px;
  transition: all 0.2s ease;
  box-shadow: var(--shadow);
}
button:hover {
  background: var(--accent-hover);
  transform: translateY(-1px);
  box-shadow: var(--shadow-lg);
}
button:active {
  transform: translateY(0);
}
button:disabled { 
  opacity: 0.5; 
  cursor: not-allowed;
  transform: none;
}
button[type="button"] {
  background: var(--panel);
  color: var(--text-secondary);
  border: 1px solid var(--border);
  padding: 8px 12px;
  font-size: 16px;
  min-width: 32px;
  height: 32px;
}
button[type="button"]:hover {
  background: #f6f8fa;
  border-color: var(--border-hover);
  color: var(--danger);
}

.errors { 
  color: var(--danger); 
  background: rgba(209, 36, 47, 0.05);
  border: 1px solid rgba(209, 36, 47, 0.2);
  border-radius: var(--radius);
  padding: 12px;
  margin-top: 16px; 
  font-size: 13px;
  min-height: 20px;
  display: none;
}
.errors:not(:empty) {
  display: block;
}

.preview { 
  background: var(--panel); 
  border: 1px solid var(--border); 
  border-radius: var(--radius-lg); 
  padding: 24px;
  box-shadow: var(--shadow);
}
.preview h2 { 
  margin: 0 0 20px; 
  font-size: 18px; 
  font-weight: 600;
  color: var(--text);
  letter-spacing: -0.025em;
}
.preview-container { 
  position: relative; 
  overflow: auto; 
  background: #f8f9fa; 
  border: 1px solid var(--border);
  border-radius: var(--radius); 
  padding: 20px;
}

.preview-stage {
  position: relative;
  width: min(100%, calc(var(--canvas-w) * 1px));
  height: calc(var(--canvas-h) * 1px);
  margin: 0 auto;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  background: repeating-conic-gradient(#ffffff 0 25%, #f6f8fa 0 50%);
  background-size: 16px 16px;
  box-shadow: var(--shadow);
}

.preview-svg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
}

.preview-overlay {
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
  transform-origin: center center;
  max-width: none;
  max-height: none;
  pointer-events: none;
  filter: drop-shadow(0 2px 8px rgba(16, 24, 40, 0.15));
  z-index: 2;
}

fieldset {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  margin: 0 0 20px;
  background: #fafbfc;
}
fieldset legend {
  padding: 0 8px;
  font-weight: 600;
  color: var(--text);
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

@media (max-width: 1024px) {
  main { 
    grid-template-columns: 1fr; 
    gap: 20px;
    padding: 20px;
  }
  header {
    padding: 20px;
  }
  .controls,
  .preview {
    padding: 20px;
  }
}