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

:root {
  --bg: #0d0d0d;
  --surface: #161616;
  --surface-2: #1e1e1e;
  --border: #2a2a2a;
  --accent: #d4f400;
  --text: #f0f0f0;
  --text-muted: #666;
  --font-mono: 'IBM Plex Mono', monospace;
  --font-sans: 'IBM Plex Sans Thai', sans-serif;
  --radius: 12px;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  font-weight: 300;
  min-height: 100vh;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding: 3rem 1rem;
  position: relative;
}

.bg-grid {
  position: fixed;
  inset: 0;
  background-image: linear-gradient(var(--border) 1px, transparent 1px), linear-gradient(90deg, var(--border) 1px, transparent 1px);
  background-size: 40px 40px;
  opacity: 0.4;
  pointer-events: none;
}

main {
  width: 100%;
  max-width: 480px;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  position: relative;
  z-index: 1;
}

.logo { font-family: var(--font-mono); font-size: 28px; font-weight: 500; letter-spacing: 0.1em; color: var(--accent); }
.tagline { font-size: 13px; color: var(--text-muted); margin-top: 4px; font-family: var(--font-mono); }

.card, .preview-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
}

.input-group { display: flex; flex-direction: column; gap: 6px; margin-bottom: 1.25rem; }

label { font-family: var(--font-mono); font-size: 11px; letter-spacing: 0.12em; color: var(--text-muted); text-transform: uppercase; }

input[type="text"] {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text);
  font-family: var(--font-mono);
  font-size: 14px;
  padding: 10px 14px;
  width: 100%;
  outline: none;
  transition: border-color 0.15s;
}
input[type="text"]:focus { border-color: var(--accent); }

.controls { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; }
.control-item { display: flex; flex-direction: column; gap: 8px; }

select {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text);
  font-family: var(--font-mono);
  font-size: 13px;
  padding: 8px 10px;
  outline: none;
  cursor: pointer;
}

.color-wrap {
  display: flex;
  align-items: center;
  gap: 8px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 6px 10px;
}
input[type="color"] { width: 24px; height: 24px; border: none; border-radius: 4px; cursor: pointer; padding: 0; background: none; }
.color-wrap span { font-family: var(--font-mono); font-size: 12px; color: var(--text-muted); }

input[type="range"] { width: 100%; accent-color: var(--accent); cursor: pointer; }

.preview-card { display: flex; flex-direction: column; align-items: center; gap: 1.25rem; }

.canvas-wrap {
  background: repeating-conic-gradient(#2a2a2a 0% 25%, #1e1e1e 0% 50%) 0 0 / 16px 16px;
  border-radius: 8px;
  display: inline-flex;
  overflow: hidden;
}
#qr-canvas { display: block; image-rendering: pixelated; }

.preview-meta { width: 100%; display: flex; align-items: center; justify-content: space-between; gap: 12px; }

#qr-label { font-family: var(--font-mono); font-size: 12px; color: var(--text-muted); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; flex: 1; }

.action-btn {
  background: var(--accent);
  color: #000;
  border: none;
  border-radius: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 500;
  padding: 8px 16px;
  cursor: pointer;
  white-space: nowrap;
  transition: opacity 0.15s, transform 0.1s;
  flex-shrink: 0;
}
.action-btn:hover { opacity: 0.85; }
.action-btn:active { transform: scale(0.97); }
.action-btn:disabled { background: var(--border); color: var(--text-muted); cursor: not-allowed; }