:root {
  --radius: 16px;
  --max-width: 1250px;
  --font: system-ui,-apple-system,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  --mono: ui-monospace,SFMono-Regular,Menlo,Consolas,"Liberation Mono",monospace;
  --transition: 0.18s ease;
  --shadow-sm: 0 2px 4px -1px rgba(0,0,0,0.25);
  --shadow: 0 6px 24px -8px rgba(0,0,0,0.35);
  --grid-gap: 4px;
}

@media (prefers-color-scheme: light) {
  :root {
    --bg: #f5f7fa;
    --bg-alt: #ffffff;
    --panel: #ffffff;
    --text: #1f2933;
    --text-dim: #556270;
    --border: #d6dde5;
    --accent: #2563eb;
    --accent-ring: rgba(37,99,235,0.35);
    --green: #16a34a;
    --green-hover: #12813d;
    --orange: #ea580c;
    --orange-hover: #c94c0a;
    --grid-bg: #eef2f6;
    --cell-border: #cfd8e0;
    --cell-bg: #ffffff;
    --cell-hover: #2563eb;
    --danger: #dc2626;
  }
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #12181e;
    --bg-alt: #1d252c;
    --panel: #222c34;
    --text: #e5edf3;
    --text-dim: #96a9b9;
    --border: #2e3a46;
    --accent: #3b82f6;
    --accent-ring: rgba(59,130,246,0.4);
    --green: #22c55e;
    --green-hover: #16a34a;
    --orange: #f97316;
    --orange-hover: #ea580c;
    --grid-bg: #1a2229;
    --cell-border: #364652;
    --cell-bg: #1f272e;
    --cell-hover: #3b82f6;
    --danger: #ef4444;
  }
}

* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  font-family: var(--font);
  background: linear-gradient(140deg,var(--bg-alt),var(--bg));
  color: var(--text);
  -webkit-font-smoothing: antialiased;
}

.app {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: clamp(1rem,2.2vw,2.3rem);
  display: flex;
  flex-direction: column;
  gap: 1.4rem;
  min-height: 100dvh;
}

header {
  text-align: center;
  padding: 0.5rem 1rem 1.1rem;
  border-radius: var(--radius);
}

h1 {
  margin: 0;
  font-size: clamp(2rem,5vw,2.85rem);
  letter-spacing: -0.75px;
}

.subtitle {
  margin: 0.7rem 0 0;
  font-size: clamp(0.9rem,1.9vw,1.1rem);
  color: var(--text-dim);
}

.panel {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.2rem 1.4rem 1.7rem;
  box-shadow: var(--shadow);
  display: flex;
  flex-direction: column;
  gap: 1.2rem;
}

form { display: flex; flex-direction: column; gap: 1.2rem; }

.row.duo {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

.field {
  flex: 1 1 220px;
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

label {
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.55px;
  text-transform: uppercase;
  color: var(--text-dim);
}

input[type="number"] {
  font: inherit;
  padding: 0.7rem 0.9rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-alt);
  color: var(--text);
  box-shadow: var(--shadow-sm);
  outline: none;
  transition: var(--transition);
}

input[type="number"]:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 4px var(--accent-ring);
}

.row.checks {
  display: flex;
  flex-wrap: wrap;
  gap: 1.4rem;
}

.check-group {
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
  min-width: 220px;
  background: var(--bg-alt);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.9rem 1rem;
  box-shadow: var(--shadow-sm) inset;
}

.group-title {
  font-size: 0.65rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.75px;
  color: var(--text-dim);
  margin-bottom: 0.2rem;
}

.check-group label {
  font-size: 0.85rem;
  font-weight: 500;
  text-transform: none;
  letter-spacing: 0.25px;
  display: flex;
  align-items: center;
  gap: 0.55rem;
  cursor: pointer;
}

.check-group input[type="checkbox"] {
  width: 18px;
  height: 18px;
  accent-color: var(--accent);
  cursor: pointer;
}

.actions {
  display: flex;
  justify-content: center;
  gap: 1rem;
  margin-top: 0.5rem;
}

.btn {
  font: inherit;
  font-weight: 650;
  letter-spacing: 0.6px;
  text-transform: uppercase;
  padding: 0.85rem 1.55rem;
  border-radius: var(--radius);
  border: none;
  cursor: pointer;
  color: #fff;
  position: relative;
  transition: var(--transition);
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  box-shadow: var(--shadow);
}

.btn.generate { background: linear-gradient(135deg,var(--green),var(--green-hover)); }
.btn.generate:hover { filter: brightness(1.06); }
.btn.reset { background: linear-gradient(135deg,var(--orange),var(--orange-hover)); }
.btn.reset:hover { filter: brightness(1.06); }
.btn:active { transform: translateY(1px); }

.hidden { display: none !important; }

#outputArea { display: flex; flex-direction: column; gap: 1.3rem; }

.matrix-wrapper {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.05rem 1.1rem 1.25rem;
  box-shadow: var(--shadow);
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
  animation: fadeIn 0.4s ease;
}

.matrix-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 0.9rem;
  flex-wrap: wrap;
}

.matrix-title {
  font-size: 1rem;
  margin: 0;
  font-weight: 700;
  letter-spacing: 0.4px;
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.badge {
  background: var(--accent);
  color: #fff;
  font-size: 0.65rem;
  font-weight: 700;
  padding: 0.25rem 0.7rem;
  border-radius: 999px;
  letter-spacing: 0.6px;
  box-shadow: var(--shadow-sm);
}

.copy-btn {
  font: inherit;
  font-size: 0.72rem;
  font-weight: 600;
  text-transform: uppercase;
  padding: 0.55rem 0.95rem;
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  letter-spacing: 0.5px;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}
.copy-btn:hover { filter: brightness(1.08); }
.copy-btn:active { transform: translateY(1px); }

.matrix-meta {
  font-size: 0.7rem;
  color: var(--text-dim);
  letter-spacing: 0.4px;
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.meta-item {
  background: var(--bg-alt);
  padding: 0.35rem 0.75rem;
  border: 1px solid var(--border);
  border-radius: 999px;
  font-weight: 500;
  font-size: 0.7rem;
  letter-spacing: 0.3px;
}

.matrix-scroll {
  background: var(--grid-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.75rem;
  position: relative;
  max-height: 65vh;
  overflow: auto;
}

.matrix-grid {
  display: grid;
  gap: var(--grid-gap);
  align-content: start;
}

.cell {
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--mono);
  font-weight: 600;
  background: var(--cell-bg);
  border: 1px solid var(--cell-border);
  border-radius: 6px;
  line-height: 1;
  user-select: none;
  font-size: 0.78rem;
  width: var(--cell-size);
  height: var(--cell-size);
  min-width: var(--cell-size);
  aspect-ratio: 1 / 1;
  box-shadow: inset 0 1px 2px rgba(0,0,0,0.15);
  transition: background 0.15s, color 0.15s;
}

.cell:hover {
  background: var(--cell-hover);
  color: #fff;
}

.matrix-scroll::-webkit-scrollbar {
  width: 10px;
  height: 10px;
}
.matrix-scroll::-webkit-scrollbar-track { background: transparent; }
.matrix-scroll::-webkit-scrollbar-thumb {
  background: var(--border);
  border-radius: 999px;
}

footer {
  margin-top: auto;
  font-size: 0.7rem;
  opacity: 0.65;
  text-align: center;
  padding: 1rem 0 0.3rem;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes shake {
  0%,100% { transform: translateX(0); }
  20% { transform: translateX(-6px); }
  40% { transform: translateX(6px); }
  60% { transform: translateX(-4px); }
  80% { transform: translateX(4px); }
}

input.invalid {
  animation: shake 0.4s ease;
  border-color: var(--danger);
  box-shadow: 0 0 0 4px rgba(220,38,38,0.35);
}

/* Responsive */
@media (max-width: 780px) {
  .row.duo { flex-direction: column; }
  .check-group { flex: 1 1 100%; }
  .matrix-header { flex-direction: column; align-items: stretch; }
  .cell { font-size: 0.68rem; }
}