:root {
  --bg: #f4f5f7;
  --card-bg: #ffffff;
  --text: #1c1e21;
  --subtle: #6b7280;
  --accent: #4f46e5;
  --accent-hover: #4338ca;
  --border: #e5e7eb;
  --error: #dc2626;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #14151a;
    --card-bg: #1e2027;
    --text: #f2f3f5;
    --subtle: #9ca3af;
    --accent: #6366f1;
    --accent-hover: #818cf8;
    --border: #2d2f38;
    --error: #f87171;
  }
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  padding: 2rem 1rem;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
}

.card {
  width: 100%;
  max-width: 440px;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 2rem;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
}

h1 {
  margin: 0 0 0.25rem;
  font-size: 1.5rem;
}

.subtitle {
  margin: 0 0 1.5rem;
  color: var(--subtle);
  font-size: 0.9rem;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
}

textarea {
  width: 100%;
  padding: 0.75rem;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--bg);
  color: var(--text);
  font-family: inherit;
  font-size: 0.95rem;
  resize: vertical;
}

textarea:focus,
select:focus,
input[type="color"]:focus,
button:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.controls {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-top: 1rem;
  flex-wrap: wrap;
}

.controls label {
  font-size: 0.85rem;
  color: var(--subtle);
}

.controls select {
  padding: 0.4rem 0.6rem;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--card-bg);
  color: var(--text);
}

.controls input[type="color"] {
  width: 40px;
  height: 32px;
  padding: 0;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: none;
  cursor: pointer;
}

button {
  width: 100%;
  margin-top: 1.25rem;
  padding: 0.75rem;
  border: none;
  border-radius: 10px;
  background: var(--accent);
  color: #fff;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s ease;
}

button:hover {
  background: var(--accent-hover);
}

#download-btn {
  background: transparent;
  border: 1px solid var(--accent);
  color: var(--accent);
}

#download-btn:hover {
  background: var(--accent);
  color: #fff;
}

.qr-output {
  margin-top: 1.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 200px;
  border: 1px dashed var(--border);
  border-radius: 12px;
  padding: 1rem;
  background: var(--bg);
}

.qr-output canvas {
  max-width: 100%;
  height: auto;
  border-radius: 4px;
}

.placeholder {
  color: var(--subtle);
  font-size: 0.9rem;
  text-align: center;
}

.error {
  margin-top: 0.75rem;
  color: var(--error);
  font-size: 0.85rem;
  text-align: center;
}

.hidden {
  display: none;
}

footer {
  color: var(--subtle);
  font-size: 0.8rem;
}