:root {
  --primary-color: #3b82f6;
  --bg-light: #0f172a;
  --bg-card: #1a2332;
  --text-light: #cbd5e1;
  --text-primary: #fff;
  --border-color: #334155;
}

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

body {
  font-family: 'DM Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: linear-gradient(135deg, var(--bg-light) 0%, #1a2332 100%);
  color: var(--text-light);
  line-height: 1.6;
  min-height: 100vh;
}

.container { max-width: 900px; margin: 0 auto; padding: 20px; }

.header {
  text-align: center;
  margin-bottom: 40px;
  padding: 30px 20px;
  background: linear-gradient(135deg, rgba(59, 130, 246, 0.1) 0%, rgba(59, 130, 246, 0.05) 100%);
  border-radius: 12px;
  border: 1px solid var(--border-color);
}

.header h1 { font-size: 2.5rem; color: var(--text-primary); margin-bottom: 10px; font-weight: 700; }
.subtitle { font-size: 1.1rem; color: var(--text-light); margin-top: 10px; }

.tool-wrapper { display: grid; gap: 20px; }

.card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 30px;
  backdrop-filter: blur(10px);
}

.card h2 { color: var(--text-primary); margin-bottom: 20px; font-size: 1.5rem; }

.input-group {
  margin-bottom: 20px;
}

.input-group label {
  display: block;
  color: var(--text-primary);
  margin-bottom: 8px;
  font-weight: 500;
}

.input-group select,
.input-group input {
  width: 100%;
  padding: 12px;
  background: var(--bg-light);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  color: var(--text-light);
  font-size: 1rem;
  transition: all 0.3s ease;
}

.input-group select:focus,
.input-group input:focus {
  outline: none;
  border-color: var(--primary-color);
}

.size-group {
  display: flex;
  align-items: center;
  gap: 15px;
  margin-bottom: 20px;
}

.size-group label { color: var(--text-primary); }
.size-group input { flex: 1; }
.size-group span { color: var(--primary-color); font-weight: 600; min-width: 50px; }

.btn-primary,
.btn-secondary {
  padding: 12px 24px;
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  margin-right: 10px;
  margin-bottom: 10px;
}

.btn-primary {
  background: var(--primary-color);
  color: white;
}

.btn-primary:hover {
  background: #2563eb;
  transform: translateY(-2px);
}

.btn-secondary {
  background: transparent;
  border: 2px solid var(--border-color);
  color: var(--text-light);
}

.btn-secondary:hover {
  border-color: var(--primary-color);
  color: var(--primary-color);
}

.results-card { display: none; }

.qr-output {
  background: var(--bg-light);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 20px;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 350px;
  margin-bottom: 20px;
}

.qr-output canvas {
  max-width: 100%;
  height: auto;
}

.download-group {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 10px;
}

.info-card {
  background: rgba(59, 130, 246, 0.05);
  border-color: var(--border-color);
}

.info-card ul {
  list-style: none;
  padding: 0;
  margin-top: 15px;
}

.info-card li {
  padding: 8px 0;
  color: var(--text-light);
  border-bottom: 1px solid var(--border-color);
}

.info-card li:last-child {
  border-bottom: none;
}

@media (max-width: 768px) {
  .header h1 { font-size: 1.8rem; }
  .card { padding: 20px; }
  .btn-primary, .btn-secondary { width: 100%; margin-right: 0; }
  .size-group { flex-direction: column; align-items: flex-start; }
}