:root {
  --background: #fbfffd;
  --surface: #f1fbf6;
  --muted: #e6f5ec;
  --primary: #527d52;
  --primary-dark: #3d653f;
  --text: #1c1b1f;
  --secondary: #4f5c50;
  --border: #b7c8b9;
  --white: #ffffff;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  min-width: 320px;
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 24px;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: var(--text);
  background:
    radial-gradient(circle at top left, #def8eb 0, transparent 38%),
    var(--background);
}
button, input, textarea { font: inherit; }
button { cursor: pointer; }

.app-card {
  width: min(100%, 980px);
  padding: clamp(24px, 4vw, 42px);
  border: 1px solid var(--border);
  border-radius: 24px;
  background: rgba(251, 255, 253, 0.95);
  box-shadow: 0 22px 60px rgba(48, 83, 52, 0.12);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 22px;
  color: var(--primary-dark);
  font-weight: 800;
  letter-spacing: .02em;
}
.logo {
  width: 38px;
  height: 38px;
  display: grid;
  place-items: center;
  border-radius: 12px;
  background: var(--primary);
  color: var(--white);
  font-size: 20px;
}

h1 {
  margin: 0 0 10px;
  font-size: clamp(30px, 5vw, 46px);
  line-height: 1.03;
}
.subtitle {
  max-width: 700px;
  margin: 0 0 30px;
  color: var(--secondary);
  line-height: 1.55;
}

.workspace {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(290px, .85fr);
  gap: 28px;
  align-items: stretch;
}
.form-column, .preview-column {
  min-width: 0;
}
.field { margin-bottom: 18px; }
label, .preview-heading strong, .history-heading strong {
  display: block;
  margin: 0 0 8px;
  font-weight: 700;
}
.label-row, .preview-heading, .history-heading {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}
.label-row small, .history-heading span {
  color: var(--secondary);
  font-size: 12px;
}

textarea, input[type="text"] {
  width: 100%;
  border: 1px solid var(--border);
  border-radius: 13px;
  background: var(--surface);
  color: var(--text);
  padding: 14px 15px;
  outline: none;
  resize: vertical;
}
textarea { min-height: 116px; }
textarea:focus, input[type="text"]:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 4px rgba(82, 125, 82, .13);
}
.color-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
}
.color-control {
  display: grid;
  grid-template-columns: 52px 1fr;
  gap: 9px;
}
input[type="color"] {
  width: 52px;
  height: 52px;
  padding: 5px;
  border: 1px solid var(--border);
  border-radius: 13px;
  background: var(--surface);
}
input[type="range"] {
  width: 100%;
  accent-color: var(--primary);
}
#sizeOutput {
  color: var(--primary-dark);
  font-weight: 800;
  font-size: 13px;
}

.preview-column {
  padding: 18px;
  border: 1px solid var(--border);
  border-radius: 18px;
  background: var(--surface);
}
.preview-heading { margin-bottom: 14px; }
.preview-heading strong { margin: 0; }
.live-badge {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 7px 10px;
  border-radius: 999px;
  background: var(--muted);
  color: var(--primary-dark);
  font-size: 12px;
  font-weight: 700;
}
.live-badge i {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--primary);
  box-shadow: 0 0 0 4px rgba(82, 125, 82, .13);
}
.qr-stage {
  min-height: 330px;
  display: grid;
  place-items: center;
  padding: 24px;
  border-radius: 16px;
  background: var(--white);
  border: 1px solid rgba(82, 125, 82, .12);
  transition: background .2s ease;
}
#qrCanvas {
  display: block;
  width: min(100%, 300px);
  height: auto;
  border-radius: 10px;
}
#qrCanvas[hidden], .empty-state[hidden] { display: none; }
.empty-state {
  display: grid;
  place-items: center;
  gap: 12px;
  color: var(--secondary);
  font-size: 42px;
  text-align: center;
}
.empty-state span { font-size: 14px; }

.button-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  margin-top: 5px;
}
.primary-button, .secondary-button, .reset-button {
  width: 100%;
  min-height: 52px;
  border-radius: 13px;
  padding: 0 18px;
  font-weight: 800;
  transition: transform .15s ease, background .15s ease, border-color .15s ease;
}
.primary-button {
  border: 0;
  background: var(--primary);
  color: var(--white);
}
.primary-button:hover { background: var(--primary-dark); }
.secondary-button, .reset-button {
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--primary-dark);
}
.secondary-button:hover, .reset-button:hover { border-color: var(--primary); }
.reset-button {
  min-height: 44px;
  margin-top: 10px;
  background: transparent;
  font-size: 13px;
}
button:active { transform: translateY(1px); }
button:disabled { cursor: not-allowed; opacity: .55; }
button:focus-visible, textarea:focus-visible, input:focus-visible {
  outline: 3px solid rgba(82, 125, 82, .24);
  outline-offset: 2px;
}

.history-section {
  margin-top: 28px;
  padding-top: 22px;
  border-top: 1px solid var(--muted);
}
.history-heading { margin-bottom: 14px; }
.history-heading strong { margin: 0; }
.history-grid {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 10px;
}
.history-card {
  min-width: 0;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 11px;
  border: 1px solid var(--border);
  border-radius: 13px;
  background: var(--surface);
  text-align: left;
}
.history-card:hover { border-color: var(--primary); }
.history-swatch {
  flex: 0 0 auto;
  width: 34px;
  height: 34px;
  border-radius: 9px;
}
.history-content { min-width: 0; display: grid; gap: 3px; }
.history-content strong {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  font-size: 12px;
}
.history-content small { color: var(--secondary); font-size: 10px; }

footer {
  display: flex;
  justify-content: space-between;
  gap: 18px;
  margin-top: 25px;
  padding-top: 18px;
  border-top: 1px solid var(--muted);
  color: var(--secondary);
  font-size: 12px;
  line-height: 1.5;
}

@media (max-width: 800px) {
  .workspace { grid-template-columns: 1fr; }
  .history-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (max-width: 560px) {
  body { padding: 12px; align-items: start; }
  .app-card { padding: 22px 18px; border-radius: 20px; }
  .color-grid, .button-row { grid-template-columns: 1fr; }
  .qr-stage { min-height: 280px; padding: 18px; }
  .history-grid { grid-template-columns: 1fr; }
  footer, .history-heading { align-items: flex-start; flex-direction: column; }
}
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { transition-duration: .01ms !important; }
}