/* ── Design tokens ─────────────────────────────────────────── */
:root {
  --bg: #f8f9fa;
  --surface: #ffffff;
  --surface2: #f1f3f5;
  --border: #dee2e6;
  --text: #212529;
  --text-muted: #6c757d;
  --accent: #228be6;
  --accent-hover: #1971c2;
  --valid: #2f9e44;
  --invalid: #e03131;
  --warn: #f59f00;
  --valid-bg: #ebfbee;
  --invalid-bg: #fff5f5;
  --keyword-color: #7048e8;
  --path-color: #228be6;
  --shadow: 0 1px 3px rgba(0,0,0,.08), 0 1px 2px rgba(0,0,0,.04);
  --radius: 6px;
  --font-mono: 'SF Mono', 'Fira Code', 'Cascadia Code', Consolas, monospace;
  --transition: 0.15s ease;
}

:root.dark {
  --bg: #1a1b1e;
  --surface: #25262b;
  --surface2: #2c2e33;
  --border: #373a40;
  --text: #c1c2c5;
  --text-muted: #909296;
  --accent: #4dabf7;
  --accent-hover: #74c0fc;
  --valid: #69db7c;
  --invalid: #ff8787;
  --warn: #ffd43b;
  --valid-bg: #132b1a;
  --invalid-bg: #2b1313;
  --keyword-color: #b197fc;
  --path-color: #74c0fc;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  font-size: 14px;
  line-height: 1.5;
}

/* ── Header ────────────────────────────────────────────────── */
header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 0 1rem;
  display: flex;
  align-items: center;
  gap: 1rem;
  height: 52px;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow);
}

.header-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--accent);
  white-space: nowrap;
  flex-shrink: 0;
}

.header-spacer { flex: 1; }

.header-controls {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-shrink: 0;
}

/* ── Buttons ────────────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.3rem 0.75rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
  color: var(--text);
  font-size: 0.8rem;
  font-weight: 500;
  cursor: pointer;
  transition: background var(--transition), border-color var(--transition), color var(--transition);
  white-space: nowrap;
}

.btn:hover {
  background: var(--surface2);
  border-color: var(--accent);
}

.btn-icon {
  padding: 0.3rem 0.5rem;
  font-size: 1rem;
  border-radius: var(--radius);
}

.btn-primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}
.btn-primary:hover {
  background: var(--accent-hover);
  border-color: var(--accent-hover);
  color: #fff;
}

/* ── Select ─────────────────────────────────────────────────── */
select.btn {
  padding-right: 1.5rem;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='6' fill='none'%3E%3Cpath d='M1 1l4 4 4-4' stroke='%236c757d' stroke-width='1.5' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 0.5rem center;
}

/* ── Main layout ────────────────────────────────────────────── */
main {
  flex: 1;
  display: flex;
  flex-direction: column;
  padding: 1rem;
  gap: 1rem;
  max-width: 1400px;
  width: 100%;
  margin: 0 auto;
}

/* ── Editors ────────────────────────────────────────────────── */
.editor-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  flex: 1;
  min-height: 0;
}

.editor-pane {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.editor-label {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

textarea.code-editor {
  flex: 1;
  min-height: 300px;
  padding: 0.75rem;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  line-height: 1.6;
  background: var(--surface);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  resize: vertical;
  outline: none;
  tab-size: 2;
  transition: border-color var(--transition), box-shadow var(--transition);
  box-shadow: var(--shadow);
}

textarea.code-editor:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent) 20%, transparent);
}

/* ── Result panel ───────────────────────────────────────────── */
.result-panel {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: border-color var(--transition);
}

.result-panel.valid  { border-color: var(--valid); }
.result-panel.invalid { border-color: var(--invalid); }
.result-panel.error  { border-color: var(--warn); }

.result-header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.5rem 0.75rem;
  background: var(--surface2);
  border-bottom: 1px solid var(--border);
}

.result-title {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.status-badge {
  font-size: 0.7rem;
  font-weight: 700;
  padding: 0.15rem 0.5rem;
  border-radius: 20px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.status-badge.valid {
  background: var(--valid-bg);
  color: var(--valid);
}

.status-badge.invalid {
  background: var(--invalid-bg);
  color: var(--invalid);
}

.error-count {
  font-size: 0.8rem;
  color: var(--text-muted);
  flex: 1;
}

/* ── Error list ─────────────────────────────────────────────── */
.error-list {
  list-style: none;
  max-height: 260px;
  overflow-y: auto;
  padding: 0.5rem;
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
}

.error-item {
  display: grid;
  grid-template-columns: minmax(120px, 220px) 1fr auto;
  gap: 0.5rem;
  align-items: center;
  padding: 0.4rem 0.6rem;
  border-radius: 4px;
  background: var(--surface2);
  border: 1px solid var(--border);
  font-size: 0.78rem;
  font-family: var(--font-mono);
  transition: background var(--transition);
}

.error-item:hover {
  background: color-mix(in srgb, var(--invalid) 8%, var(--surface2));
}

.error-item.parse-error {
  border-color: var(--warn);
  background: color-mix(in srgb, var(--warn) 8%, var(--surface2));
}

.error-path {
  color: var(--path-color);
  font-weight: 600;
  word-break: break-all;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.error-message {
  color: var(--text);
  word-break: break-word;
}

.error-keyword {
  color: var(--keyword-color);
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  white-space: nowrap;
}

.result-panel.valid .error-list::after {
  content: '✓ ' attr(data-msg);
  display: block;
  text-align: center;
  padding: 1rem;
  color: var(--valid);
  font-size: 0.9rem;
  font-weight: 600;
}

/* ── Footer ─────────────────────────────────────────────────── */
footer {
  text-align: center;
  padding: 0.75rem;
  font-size: 0.75rem;
  color: var(--text-muted);
  border-top: 1px solid var(--border);
}

footer a {
  color: var(--accent);
  text-decoration: none;
}

footer a:hover { text-decoration: underline; }

/* ── Scrollbar ──────────────────────────────────────────────── */
.error-list::-webkit-scrollbar { width: 6px; }
.error-list::-webkit-scrollbar-track { background: transparent; }
.error-list::-webkit-scrollbar-thumb {
  background: var(--border);
  border-radius: 3px;
}

/* ── Responsive ─────────────────────────────────────────────── */
@media (max-width: 768px) {
  .editor-row {
    grid-template-columns: 1fr;
  }

  .header-title { font-size: 0.85rem; }

  textarea.code-editor { min-height: 200px; }

  .error-item {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 480px) {
  header { gap: 0.5rem; padding: 0 0.5rem; }
  main { padding: 0.5rem; gap: 0.5rem; }
  .header-controls { gap: 0.25rem; }
}