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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: #0f172a;
  color: #e2e8f0;
  min-height: 100vh;
  padding: 2rem 1rem;
}

.container {
  max-width: 900px;
  margin: 0 auto;
}

header {
  text-align: center;
  margin-bottom: 2rem;
}

h1 {
  font-size: 1.75rem;
  font-weight: 700;
  color: #f8fafc;
  margin-bottom: 0.5rem;
}

h1 span { color: #38bdf8; }

.subtitle {
  color: #94a3b8;
  font-size: 0.95rem;
}

.panel {
  background: #1e293b;
  border: 1px solid #334155;
  border-radius: 12px;
  overflow: hidden;
  margin-bottom: 1.5rem;
}

.panel-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 1.25rem;
  background: #1e293b;
  border-bottom: 1px solid #334155;
}

.panel-title {
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: #94a3b8;
}

textarea {
  width: 100%;
  min-height: 220px;
  padding: 1.25rem;
  background: #0f172a;
  color: #e2e8f0;
  border: none;
  outline: none;
  font-family: "JetBrains Mono", "Fira Code", "Cascadia Code", Consolas, monospace;
  font-size: 0.875rem;
  line-height: 1.6;
  resize: vertical;
  tab-size: 2;
}

textarea::placeholder { color: #475569; }

.actions {
  display: flex;
  gap: 0.75rem;
  align-items: center;
  flex-wrap: wrap;
}

button {
  padding: 0.6rem 1.5rem;
  border-radius: 8px;
  border: none;
  font-size: 0.875rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.15s ease;
}

.btn-primary {
  background: #2563eb;
  color: #fff;
}
.btn-primary:hover { background: #1d4ed8; }
.btn-primary:active { transform: scale(0.97); }

.btn-secondary {
  background: #334155;
  color: #cbd5e1;
}
.btn-secondary:hover { background: #475569; }

.panel-tools {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.btn-copy {
  padding: 0.25rem 0.6rem;
  border-radius: 5px;
  border: 1px solid #475569;
  background: #1e293b;
  color: #94a3b8;
  font-size: 0.7rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.15s ease;
  text-transform: uppercase;
  letter-spacing: 0.03em;
}
.btn-copy:hover { background: #334155; color: #e2e8f0; border-color: #64748b; }
.btn-copy.copied { background: #065f46; color: #6ee7b7; border-color: #065f46; }

.panel-tools select {
  appearance: none;
  padding: 0.35rem 2rem 0.35rem 0.75rem;
  border-radius: 6px;
  border: 1px solid #475569;
  background: #1e293b url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' fill='%2394a3b8' viewBox='0 0 16 16'%3E%3Cpath d='M8 11L3 6h10z'/%3E%3C/svg%3E") no-repeat right 0.5rem center;
  color: #cbd5e1;
  font-size: 0.8rem;
  font-family: inherit;
  cursor: pointer;
  outline: none;
}
.panel-tools select:hover { border-color: #64748b; }

.output-area {
  padding: 1.25rem;
  background: #0f172a;
  font-family: "JetBrains Mono", "Fira Code", "Cascadia Code", Consolas, monospace;
  font-size: 0.875rem;
  line-height: 1.6;
  white-space: pre-wrap;
  word-break: break-all;
  min-height: 80px;
  color: #a5f3fc;
}

.output-area.error {
  color: #fca5a5;
}

.output-area.empty {
  color: #475569;
  font-style: italic;
  font-family: inherit;
}

.verify-area {
  padding: 1.25rem;
  background: #0f172a;
  font-family: "JetBrains Mono", "Fira Code", "Cascadia Code", Consolas, monospace;
  font-size: 0.875rem;
  line-height: 1.6;
  white-space: pre-wrap;
  word-break: break-all;
  min-height: 60px;
  color: #86efac;
}

.verify-area.error { color: #fca5a5; }
.verify-area.empty { color: #475569; font-style: italic; font-family: inherit; }

.badge {
  display: inline-block;
  font-size: 0.7rem;
  padding: 0.2rem 0.5rem;
  border-radius: 4px;
  font-weight: 600;
  text-transform: uppercase;
}

.badge-success { background: #065f46; color: #6ee7b7; }
.badge-error { background: #7f1d1d; color: #fca5a5; }
.badge-info { background: #1e3a5f; color: #93c5fd; }

.panel-output { margin-top: 1.5rem; }

.panel-options { margin-bottom: 1rem; }

.options-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0;
}

.option-item {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.65rem 1.25rem;
  cursor: pointer;
  transition: background 0.1s ease;
  border-bottom: 1px solid #1e293b;
  border-right: 1px solid #1e293b;
}
.option-item:hover { background: #1a2536; }

.option-item input[type="checkbox"] {
  width: 16px;
  height: 16px;
  accent-color: #2563eb;
  cursor: pointer;
  flex-shrink: 0;
}

.option-info {
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
  min-width: 0;
}

.option-name {
  font-family: "JetBrains Mono", "Fira Code", "Cascadia Code", Consolas, monospace;
  font-size: 0.78rem;
  color: #e2e8f0;
  font-weight: 500;
}

.option-desc {
  font-size: 0.7rem;
  color: #64748b;
}

.option-number {
  cursor: default;
}

.option-number input[type="number"] {
  width: 80px;
  padding: 0.3rem 0.5rem;
  border-radius: 5px;
  border: 1px solid #475569;
  background: #0f172a;
  color: #e2e8f0;
  font-family: "JetBrains Mono", "Fira Code", "Cascadia Code", Consolas, monospace;
  font-size: 0.8rem;
  outline: none;
  text-align: center;
  flex-shrink: 0;
}
.option-number input[type="number"]:focus { border-color: #2563eb; }
.option-number input[type="number"]::placeholder { color: #475569; font-style: italic; }

.btn-reset {
  padding: 0.25rem 0.6rem;
  border-radius: 5px;
  border: 1px solid #475569;
  background: #1e293b;
  color: #94a3b8;
  font-size: 0.7rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.15s ease;
  text-transform: uppercase;
  letter-spacing: 0.03em;
}
.btn-reset:hover { background: #334155; color: #e2e8f0; border-color: #64748b; }

.hidden { display: none; }

footer {
  text-align: center;
  margin-top: 2rem;
  color: #64748b;
  font-size: 0.8rem;
}

footer a {
  color: #38bdf8;
  text-decoration: none;
}
footer a:hover { text-decoration: underline; }

@media (max-width: 600px) {
  body { padding: 1rem 0.5rem; }
  h1 { font-size: 1.3rem; }
  textarea { min-height: 180px; font-size: 0.8rem; }
  .actions { flex-direction: column; }
  button, .examples-dropdown select { width: 100%; }
  .options-grid { grid-template-columns: 1fr; }
  .option-item { border-right: none; }
}