/* ===== DESIGN TOKENS ===== */
:root {
  --bg: #fafbfc;
  --bg-subtle: #f3f4f6;
  --surface: #ffffff;
  --surface-hover: #f9fafb;
  --ink: #111827;
  --ink-secondary: #4b5563;
  --ink-muted: #9ca3af;
  --accent: #4f46e5;
  --accent-light: #eef2ff;
  --accent-hover: #4338ca;
  --accent-glow: rgba(79, 70, 229, 0.15);
  --success: #10b981;
  --border: #e5e7eb;
  --border-subtle: #f3f4f6;
  --ring: rgba(79, 70, 229, 0.3);
  --shadow-xs: 0 1px 2px rgba(0,0,0,0.04);
  --shadow-sm: 0 2px 8px rgba(0,0,0,0.06);
  --shadow-md: 0 8px 24px rgba(0,0,0,0.08);
  --shadow-lg: 0 24px 48px rgba(0,0,0,0.12);
  --shadow-glow: 0 0 40px rgba(79, 70, 229, 0.08);
  --radius-sm: 8px;
  --radius: 14px;
  --radius-lg: 20px;
  --radius-xl: 24px;
  --transition: 200ms cubic-bezier(0.4, 0, 0.2, 1);
  --font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

[data-theme="dark"] {
  --bg: #09090b;
  --bg-subtle: #18181b;
  --surface: #1c1c22;
  --surface-hover: #27272a;
  --ink: #fafafa;
  --ink-secondary: #a1a1aa;
  --ink-muted: #71717a;
  --accent: #818cf8;
  --accent-light: rgba(129, 140, 248, 0.1);
  --accent-hover: #6366f1;
  --accent-glow: rgba(129, 140, 248, 0.2);
  --border: #27272a;
  --border-subtle: #1c1c22;
  --ring: rgba(129, 140, 248, 0.4);
  --shadow-xs: 0 1px 2px rgba(0,0,0,0.2);
  --shadow-sm: 0 2px 8px rgba(0,0,0,0.3);
  --shadow-md: 0 8px 24px rgba(0,0,0,0.4);
  --shadow-lg: 0 24px 48px rgba(0,0,0,0.5);
  --shadow-glow: 0 0 40px rgba(129, 140, 248, 0.1);
}

/* ===== RESET ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--ink);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  min-height: 100vh;
}
button { font-family: inherit; cursor: pointer; }
input, textarea, select { font-family: inherit; }

/* ===== HEADER ===== */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: color-mix(in srgb, var(--surface) 80%, transparent);
  backdrop-filter: blur(12px) saturate(1.5);
  -webkit-backdrop-filter: blur(12px) saturate(1.5);
  border-bottom: 1px solid var(--border);
}
.header__inner {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0.75rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  text-decoration: none;
  color: var(--ink);
}
.logo__icon { color: var(--accent); }
.logo__text {
  font-weight: 800;
  font-size: 1.15rem;
  letter-spacing: -0.03em;
}
.header__nav { display: flex; align-items: center; gap: 1rem; }
.nav-link {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--ink-secondary);
  text-decoration: none;
  transition: color var(--transition);
}
.nav-link:hover { color: var(--accent); }
.theme-btn {
  width: 36px;
  height: 36px;
  display: grid;
  place-items: center;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--surface);
  color: var(--ink-secondary);
  transition: all var(--transition);
}
.theme-btn:hover { border-color: var(--accent); color: var(--accent); }
.icon-moon { display: none; }
[data-theme="dark"] .icon-sun { display: none; }
[data-theme="dark"] .icon-moon { display: block; }

/* ===== HERO ===== */
.hero {
  text-align: center;
  padding: 3rem 1.5rem 1.5rem;
}
.hero__title {
  font-size: clamp(1.75rem, 4vw, 2.75rem);
  font-weight: 900;
  letter-spacing: -0.04em;
  line-height: 1.1;
}
.gradient-text {
  background: linear-gradient(135deg, var(--accent) 0%, #ec4899 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero__sub {
  margin-top: 0.5rem;
  color: var(--ink-muted);
  font-size: 1rem;
}

/* ===== APP LAYOUT ===== */
.app {
  padding: 0 1.5rem 4rem;
}
.app__inner {
  max-width: 1280px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1fr 400px;
  gap: 2rem;
  align-items: start;
}
.app__left { display: flex; flex-direction: column; gap: 1.5rem; }
.app__right {}

/* ===== CARD ===== */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition);
}
.card:hover { box-shadow: var(--shadow-md); }
.card--sticky {
  position: sticky;
  top: 80px;
}
.card__header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 1.25rem;
}
.card__step {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--accent);
  color: #fff;
  font-size: 0.8rem;
  font-weight: 700;
  display: grid;
  place-items: center;
  flex-shrink: 0;
}
.card__title {
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

/* ===== TYPE GRID ===== */
.type-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(90px, 1fr));
  gap: 0.5rem;
}
.type-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.3rem;
  padding: 0.7rem 0.4rem;
  border: 1.5px solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
  color: var(--ink-secondary);
  font-size: 0.75rem;
  font-weight: 600;
  transition: all var(--transition);
}
.type-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-light);
  transform: translateY(-1px);
}
.type-btn.active {
  border-color: var(--accent);
  background: var(--accent-light);
  color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-glow);
}
.type-btn__icon { font-size: 1.3rem; line-height: 1; }
.type-btn__label { letter-spacing: 0.01em; }

/* ===== FORM ===== */
.form-container { min-height: 120px; }
.form-group { margin-bottom: 1rem; }
.form-group label {
  display: block;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--ink-secondary);
  margin-bottom: 0.35rem;
  letter-spacing: 0.01em;
}
.form-group input,
.form-group textarea,
.form-group select {
  width: 100%;
  padding: 0.65rem 0.85rem;
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--bg-subtle);
  color: var(--ink);
  font-size: 0.9rem;
  transition: all var(--transition);
}
.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--ring);
  background: var(--surface);
}
.form-group textarea {
  resize: vertical;
  min-height: 80px;
  line-height: 1.5;
}
.form-group input::placeholder,
.form-group textarea::placeholder {
  color: var(--ink-muted);
}
.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
}

/* ===== QR PREVIEW ===== */
.qr-preview {
  position: relative;
  display: grid;
  place-items: center;
  min-height: 300px;
  border-radius: var(--radius);
  background: var(--bg-subtle);
  border: 2px dashed var(--border);
  padding: 1.5rem;
  margin-bottom: 1.25rem;
  transition: all var(--transition);
}
.qr-preview.has-qr {
  border-style: solid;
  border-color: var(--accent-glow);
  box-shadow: var(--shadow-glow);
}
.qr-preview canvas {
  display: none;
  max-width: 100%;
  border-radius: var(--radius-sm);
  transition: transform var(--transition);
}
.qr-preview canvas.visible {
  display: block;
  animation: fadeScale 300ms ease forwards;
}
.qr-placeholder {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.75rem;
  color: var(--ink-muted);
  font-size: 0.9rem;
}
.qr-placeholder.hidden { display: none; }

@keyframes fadeScale {
  from { opacity: 0; transform: scale(0.92); }
  to { opacity: 1; transform: scale(1); }
}

/* ===== CUSTOMIZE ===== */
.customize {
  margin-bottom: 1.25rem;
  padding: 1rem;
  background: var(--bg-subtle);
  border-radius: var(--radius);
  border: 1px solid var(--border-subtle);
}
.customize__title {
  font-size: 0.78rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--ink-muted);
  margin-bottom: 0.85rem;
}
.customize__grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
}
.customize__item { display: flex; flex-direction: column; gap: 0.35rem; }
.customize__item--full { grid-column: 1 / -1; }
.customize__item label {
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--ink-secondary);
}
.color-pick {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.color-pick input[type="color"] {
  width: 36px;
  height: 30px;
  border: 1.5px solid var(--border);
  border-radius: 6px;
  padding: 2px;
  cursor: pointer;
  background: var(--surface);
}
.color-pick__val {
  font-size: 0.78rem;
  font-family: 'SF Mono', 'Fira Code', monospace;
  color: var(--ink-muted);
}
input[type="range"] {
  width: 100%;
  accent-color: var(--accent);
  height: 6px;
  border-radius: 3px;
  cursor: pointer;
}

/* ===== DOWNLOAD BUTTONS ===== */
.download-actions {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.6rem;
}
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.7rem 1rem;
  border: none;
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  font-weight: 600;
  transition: all var(--transition);
  text-decoration: none;
}
.btn--download {
  background: var(--accent);
  color: #ffffff;
  box-shadow: 0 2px 8px var(--accent-glow);
}
.btn--download:hover:not(:disabled) {
  background: var(--accent-hover);
  transform: translateY(-1px);
  box-shadow: 0 4px 16px var(--accent-glow);
}
.btn--outline {
  background: var(--surface);
  color: var(--ink);
  border: 1.5px solid var(--border);
  box-shadow: none;
}
.btn--outline:hover:not(:disabled) {
  border-color: var(--accent);
  color: var(--accent);
  transform: translateY(-1px);
}
.btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
  transform: none !important;
  box-shadow: none !important;
}

/* ===== FOOTER ===== */
.footer {
  border-top: 1px solid var(--border);
  padding: 1.5rem;
  margin-top: 2rem;
}
.footer__inner {
  max-width: 1280px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.82rem;
  color: var(--ink-muted);
}
.footer__link {
  color: var(--accent);
  text-decoration: none;
  font-weight: 500;
}
.footer__link:hover { text-decoration: underline; }

/* ===== RESPONSIVE ===== */
@media (max-width: 920px) {
  .app__inner {
    grid-template-columns: 1fr;
  }
  .card--sticky {
    position: static;
  }
  .hero { padding: 2rem 1rem 1rem; }
}
@media (max-width: 600px) {
  .header__inner { padding: 0.6rem 1rem; }
  .app { padding: 0 1rem 3rem; }
  .card { padding: 1.25rem; }
  .type-grid { grid-template-columns: repeat(auto-fill, minmax(75px, 1fr)); gap: 0.4rem; }
  .type-btn { padding: 0.55rem 0.3rem; font-size: 0.7rem; }
  .type-btn__icon { font-size: 1.1rem; }
  .customize__grid { grid-template-columns: 1fr; }
  .download-actions { grid-template-columns: 1fr; }
  .hero__title { font-size: 1.5rem; }
  .footer__inner { flex-direction: column; gap: 0.5rem; text-align: center; }
}