.dev-tool {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: clamp(1rem, 3vw, 1.75rem);
  box-shadow: var(--shadow-sm);
  margin-bottom: var(--space-8);
}

.dev-form {
  display: grid;
  gap: var(--space-4);
  grid-template-columns: 1fr;
}
@media (min-width: 640px) { .dev-form { grid-template-columns: repeat(2, 1fr); } }
@media (min-width: 900px) { .dev-form { grid-template-columns: repeat(3, 1fr); } }

.dev-field { display: flex; flex-direction: column; gap: 0.35rem; }
.dev-field label {
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--color-text);
}
.dev-field input,
.dev-field select,
.dev-field textarea {
  padding: 0.6rem 0.75rem;
  font-size: 0.9375rem;
  color: var(--color-text);
  background: var(--color-bg);
  border: 1px solid var(--color-border-strong);
  border-radius: var(--radius-md);
  min-height: 42px;
  transition: border-color var(--transition), box-shadow var(--transition);
}
.dev-field input:focus,
.dev-field select:focus,
.dev-field textarea:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px var(--color-primary-light);
}
.dev-field textarea { min-height: 100px; font-family: var(--font-mono); font-size: 0.875rem; }
.dev-field-hint {
  font-size: 0.75rem;
  color: var(--color-text-muted);
  line-height: 1.5;
}

.dev-output-heading {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  margin-top: var(--space-5);
  margin-bottom: var(--space-3);
  padding-bottom: var(--space-2);
  border-bottom: 1px solid var(--color-border);
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--color-text);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.dev-code {
  background: #0F172A;
  border-radius: var(--radius-md);
  overflow: hidden;
  margin-bottom: var(--space-4);
}
.dev-code-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  padding: 0.6rem 1rem;
  background: rgba(255, 255, 255, 0.03);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}
.dev-code-lang {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 600;
  color: rgba(255, 255, 255, 0.5);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}
.dev-code-copy {
  padding: 0.3rem 0.75rem;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--color-teal);
  background: rgba(13, 148, 136, 0.15);
  border-radius: var(--radius-xs);
  cursor: pointer;
  min-height: 28px;
  transition: background var(--transition), color var(--transition);
}
.dev-code-copy:hover { background: var(--color-teal); color: #fff; }
.dev-code-copy.is-copied { background: var(--color-teal); color: #fff; }
.dev-code-body {
  padding: 1rem 1.25rem;
  margin: 0;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  line-height: 1.7;
  color: #E2E8F0;
  overflow-x: auto;
  white-space: pre;
}

.dev-preview {
  margin-top: var(--space-4);
  padding: clamp(1rem, 3vw, 1.75rem);
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
}
.dev-preview-text {
  color: var(--color-text);
  word-break: break-word;
  line-height: 1.5;
}

.dev-tabs {
  display: flex;
  gap: 0.25rem;
  border-bottom: 1px solid var(--color-border);
  margin-bottom: var(--space-4);
  flex-wrap: wrap;
}
.dev-tab {
  padding: 0.6rem 1rem;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--color-text-secondary);
  background: transparent;
  border: none;
  border-bottom: 2px solid transparent;
  cursor: pointer;
  margin-bottom: -1px;
  min-height: 40px;
  transition: color var(--transition), border-color var(--transition);
}
.dev-tab:hover { color: var(--color-text); }
.dev-tab.is-active {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
}
.dev-tab-panel { display: none; }
.dev-tab-panel.is-active { display: block; }

.dev-result-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: var(--space-3);
  padding: 0.6rem 0;
  border-bottom: 1px solid var(--color-border);
  font-size: 0.875rem;
}
.dev-result-row:last-child { border-bottom: none; }
.dev-result-key {
  font-weight: 600;
  color: var(--color-text-secondary);
  font-size: 0.8125rem;
}
.dev-result-val {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  color: var(--color-text);
  background: var(--color-surface);
  padding: 0.2rem 0.55rem;
  border-radius: var(--radius-xs);
  border: 1px solid var(--color-border);
}
.dev-result-val.good { color: var(--color-teal); border-color: var(--color-teal-light); background: var(--color-teal-light); }
.dev-result-val.warn { color: #92400E; border-color: #FEF3C7; background: #FEF3C7; }
.dev-result-val.bad { color: #991B1B; border-color: #FEE2E2; background: #FEE2E2; }

.dev-status {
  padding: var(--space-3) var(--space-4);
  border-radius: var(--radius-md);
  font-size: 0.9rem;
  font-weight: 500;
  line-height: 1.5;
  margin-block: var(--space-3);
}
.dev-status-success {
  background: var(--color-teal-light);
  color: var(--color-teal);
  border-left: 3px solid var(--color-teal);
}
.dev-status-error {
  background: #FEE2E2;
  color: #991B1B;
  border-left: 3px solid var(--color-danger);
}
.dev-status-info {
  background: var(--color-primary-light);
  color: var(--color-primary);
  border-left: 3px solid var(--color-primary);
}

.dev-callout {
  padding: var(--space-4) var(--space-5);
  background: var(--color-teal-light);
  border-left: 3px solid var(--color-teal);
  border-radius: var(--radius-md);
  font-size: 0.9375rem;
  color: var(--color-text-secondary);
  line-height: 1.65;
  margin-block: var(--space-4);
}
.dev-callout strong { color: var(--color-teal); }
.dev-callout-warn {
  background: #FEF3C7;
  border-left-color: #D97706;
}
.dev-callout-warn strong { color: #92400E; }

.dev-checklist {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  margin-block: var(--space-4);
  padding: var(--space-3);
  background: var(--color-bg);
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
}
.dev-checklist-item {
  display: flex;
  align-items: flex-start;
  gap: 0.6rem;
  font-size: 0.9rem;
  color: var(--color-text-secondary);
  line-height: 1.6;
}
.dev-checklist-item strong { color: var(--color-text); }
.dev-checklist-item::before {
  content: "";
  flex-shrink: 0;
  width: 18px;
  height: 18px;
  margin-top: 2px;
  border-radius: var(--radius-full);
  background: var(--color-teal-light);
  border: 2px solid var(--color-teal);
}
.dev-checklist-item.is-done::before {
  background: var(--color-teal);
}

.dev-table {
  width: 100%;
  border-collapse: collapse;
  margin-block: var(--space-4);
  font-size: 0.875rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
}
.dev-table th,
.dev-table td {
  padding: 0.7rem 0.9rem;
  text-align: left;
  border-bottom: 1px solid var(--color-border);
}
.dev-table th {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--color-text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  background: var(--color-bg);
}
.dev-table td {
  color: var(--color-text);
  vertical-align: top;
}
.dev-table tr:last-child td { border-bottom: none; }
.dev-table code {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  padding: 0.1rem 0.35rem;
  background: var(--color-primary-light);
  color: var(--color-primary);
  border-radius: var(--radius-xs);
}

.dev-file-upload {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--space-3);
  padding: clamp(1.5rem, 4vw, 2.5rem) var(--space-4);
  text-align: center;
  background: var(--color-bg);
  border: 2px dashed var(--color-border-strong);
  border-radius: var(--radius-lg);
  cursor: pointer;
  transition: border-color var(--transition), background var(--transition);
  min-height: 160px;
}
.dev-file-upload:hover,
.dev-file-upload.is-dragover {
  border-color: var(--color-primary);
  background: var(--color-primary-light);
}
.dev-file-upload.has-file {
  border-style: solid;
  border-color: var(--color-teal);
  background: var(--color-teal-light);
}
.dev-file-upload input[type="file"] {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  opacity: 0;
  cursor: pointer;
}
.dev-file-upload svg { color: var(--color-primary); }
.dev-file-title {
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--color-text);
}
.dev-file-hint {
  font-size: 0.8125rem;
  color: var(--color-text-secondary);
}

.dev-playground-editor {
  width: 100%;
  min-height: 200px;
  padding: var(--space-4);
  font-family: var(--font-mono);
  font-size: 0.875rem;
  line-height: 1.7;
  color: #E2E8F0;
  background: #0F172A;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  resize: vertical;
}
.dev-playground-editor:focus {
  outline: none;
  border-color: var(--color-primary);
}

.dev-select-row {
  display: flex;
  gap: var(--space-2);
}
.dev-select-row select { flex: 1; }

.dev-guide-section { margin-top: var(--space-10); }
.dev-guide-section h2 {
  font-size: clamp(1.25rem, 1vw + 1rem, 1.75rem);
  margin-bottom: var(--space-3);
  color: var(--color-text);
}
.dev-guide-section h3 {
  font-size: 1.0625rem;
  margin-top: var(--space-5);
  margin-bottom: var(--space-2);
  color: var(--color-text);
}
.dev-guide-section p,
.dev-guide-section li {
  font-size: 0.975rem;
  line-height: 1.7;
  color: var(--color-text-secondary);
}
.dev-guide-section ul,
.dev-guide-section ol {
  padding-left: 1.4rem;
  margin-block: var(--space-3);
}
.dev-guide-section ul { list-style: disc; }
.dev-guide-section ol { list-style: decimal; }
.dev-guide-section li { margin-bottom: 0.4rem; }
.dev-guide-section code {
  font-family: var(--font-mono);
  font-size: 0.875em;
  padding: 0.1em 0.35em;
  background: var(--color-primary-light);
  color: var(--color-primary);
  border-radius: var(--radius-xs);
}