:root,
:root[data-theme="light"] {
  --bg: #ffffff;
  --bg-muted: #f6f8fa;
  --bg-elevated: #ffffff;
  --border: #d0d7de;
  --border-muted: #eaeef2;
  --text: #1f2328;
  --text-muted: #656d76;
  --accent: #0969da;
  --accent-hover: #0860c9;
  --accent-text: #ffffff;
  --added-bg: #dafbe1;
  --added-bg-strong: #aceebb;
  --added-text: #116329;
  --removed-bg: #ffebe9;
  --removed-bg-strong: #ffcecb;
  --removed-text: #82071e;
  --modified-bg: #fff8c5;
  --modified-bg-strong: #fae17d;
  --modified-text: #7d4e00;
  --unchanged-badge-bg: #d0d7de;
  --unchanged-badge-text: #424a53;
  --gutter: #f6f8fa;
  --empty-cell: #f6f8fa;
  --kbd-bg: rgba(175, 184, 193, 0.2);
  --button-secondary-bg: #f6f8fa;
  --button-secondary-hover: #eef1f4;
  --indent-guide: #afb8c1;
  --composite-tag: #656d76;
  --composite-tag-bg: rgba(175, 184, 193, 0.25);
  --focus-ring: rgba(9, 105, 218, 0.3);
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
}

:root[data-theme="dark"] {
  --bg: #0d1117;
  --bg-muted: #161b22;
  --bg-elevated: #161b22;
  --border: #30363d;
  --border-muted: #21262d;
  --text: #e6edf3;
  --text-muted: #8b949e;
  --accent: #2f81f7;
  --accent-hover: #4493f8;
  --accent-text: #ffffff;
  --added-bg: #0f3a1f;
  --added-bg-strong: #196c2e;
  --added-text: #aff5b4;
  --removed-bg: #4a1313;
  --removed-bg-strong: #82071e;
  --removed-text: #ffcecb;
  --modified-bg: #4a3a06;
  --modified-bg-strong: #7d5e00;
  --modified-text: #ffea7f;
  --unchanged-badge-bg: #30363d;
  --unchanged-badge-text: #c9d1d9;
  --gutter: #161b22;
  --empty-cell: #0d1117;
  --kbd-bg: rgba(110, 118, 129, 0.4);
  --button-secondary-bg: #21262d;
  --button-secondary-hover: #30363d;
  --indent-guide: #484f58;
  --composite-tag: #8b949e;
  --composite-tag-bg: rgba(110, 118, 129, 0.3);
  --focus-ring: rgba(47, 129, 247, 0.4);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
  transition: background-color 0.15s, color 0.15s;
}

.app-header {
  border-bottom: 1px solid var(--border);
  padding: 20px 32px;
  background: var(--bg-muted);
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
}

.header-left { min-width: 0; }

.app-header h1 {
  margin: 0;
  font-size: 22px;
  font-weight: 600;
}

.subtitle {
  margin: 4px 0 0;
  color: var(--text-muted);
  font-size: 14px;
}

.subtitle code {
  background: var(--kbd-bg);
  padding: 2px 6px;
  border-radius: 4px;
  font-family: var(--mono);
  font-size: 12px;
}

.theme-toggle {
  background: var(--button-secondary-bg);
  color: var(--text);
  border: 1px solid var(--border);
  padding: 6px 12px;
  font-size: 13px;
  border-radius: 6px;
  cursor: pointer;
  white-space: nowrap;
}

.theme-toggle:hover { background: var(--button-secondary-hover); }

.container {
  max-width: 1400px;
  margin: 0 auto;
  padding: 24px 32px 64px;
}

.inputs {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.input-group { display: flex; flex-direction: column; }

.input-group label {
  font-size: 13px;
  font-weight: 600;
  margin-bottom: 6px;
}

textarea {
  width: 100%;
  min-height: 180px;
  padding: 10px 12px;
  font-family: var(--mono);
  font-size: 13px;
  border: 1px solid var(--border);
  border-radius: 6px;
  resize: vertical;
  background: var(--bg-elevated);
  color: var(--text);
}

textarea:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--focus-ring);
}

.actions {
  display: flex;
  gap: 8px;
  margin: 16px 0 24px;
}

button {
  padding: 6px 16px;
  font-size: 14px;
  font-weight: 500;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: var(--accent);
  color: var(--accent-text);
  cursor: pointer;
  transition: background 0.15s;
}

button:hover { background: var(--accent-hover); }

button.secondary {
  background: var(--button-secondary-bg);
  color: var(--text);
}

button.secondary:hover { background: var(--button-secondary-hover); }

.summary {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 16px;
  padding: 12px 16px;
  background: var(--bg-muted);
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 13px;
}

.summary-item { display: flex; align-items: center; gap: 6px; }

.summary-item .badge {
  display: inline-block;
  min-width: 24px;
  text-align: center;
  padding: 2px 8px;
  border-radius: 10px;
  font-weight: 600;
  font-family: var(--mono);
}

.badge.added { background: var(--added-bg-strong); color: var(--added-text); }
.badge.removed { background: var(--removed-bg-strong); color: var(--removed-text); }
.badge.modified { background: var(--modified-bg-strong); color: var(--modified-text); }
.badge.unchanged { background: var(--unchanged-badge-bg); color: var(--unchanged-badge-text); }

.diff {
  border: 1px solid var(--border);
  border-radius: 6px;
  overflow: hidden;
  font-family: var(--mono);
  font-size: 12.5px;
  background: var(--bg-elevated);
}

.diff-header {
  display: grid;
  grid-template-columns: 1fr 1fr;
  background: var(--bg-muted);
  border-bottom: 1px solid var(--border);
}

.diff-side {
  padding: 8px 12px;
  font-weight: 600;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: 13px;
}

.diff-side + .diff-side { border-left: 1px solid var(--border); }

.diff-body { display: grid; grid-template-columns: 1fr 1fr; }

.diff-cell {
  display: grid;
  grid-template-columns: 40px 16px 1fr;
  align-items: start;
  padding: 0;
  border-top: 1px solid var(--border-muted);
  min-height: 22px;
  word-break: break-word;
}

.diff-cell.right { border-left: 1px solid var(--border); }

.diff-cell .ln {
  color: var(--text-muted);
  text-align: right;
  padding: 2px 8px;
  user-select: none;
  background: var(--gutter);
  font-size: 11px;
}

.diff-cell .sign {
  text-align: center;
  padding: 2px 0;
  user-select: none;
  color: var(--text-muted);
  font-weight: 600;
}

.diff-cell .code {
  padding: 2px 8px;
  white-space: pre-wrap;
}

.diff-cell.added { background: var(--added-bg); }
.diff-cell.added .sign { color: var(--added-text); }
.diff-cell.added .ln { background: color-mix(in srgb, var(--added-bg) 70%, var(--gutter)); }

.diff-cell.removed { background: var(--removed-bg); }
.diff-cell.removed .sign { color: var(--removed-text); }
.diff-cell.removed .ln { background: color-mix(in srgb, var(--removed-bg) 70%, var(--gutter)); }

.diff-cell.modified { background: var(--modified-bg); }
.diff-cell.modified .sign { color: var(--modified-text); }
.diff-cell.modified .ln { background: color-mix(in srgb, var(--modified-bg) 70%, var(--gutter)); }

.diff-cell.empty { background: var(--empty-cell); }

.token-diff {
  border-radius: 2px;
  padding: 0 2px;
}

.diff-cell.added .token-diff,
.diff-cell.modified.right .token-diff { background: var(--added-bg-strong); color: var(--added-text); }

.diff-cell.removed .token-diff,
.diff-cell.modified.left .token-diff { background: var(--removed-bg-strong); color: var(--removed-text); }

/* Indentation guides for nested struct/array fields */
.indent-guide {
  color: var(--indent-guide);
  user-select: none;
  white-space: pre;
}

.col-name { color: var(--text); font-weight: 500; }

.composite-tag {
  display: inline-block;
  margin-left: 6px;
  padding: 0 6px;
  border-radius: 10px;
  font-size: 10.5px;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-weight: 500;
  color: var(--composite-tag);
  background: var(--composite-tag-bg);
  vertical-align: 1px;
}

.hidden { display: none; }

.empty-state {
  text-align: center;
  padding: 32px;
  color: var(--text-muted);
}

@media (max-width: 800px) {
  .inputs { grid-template-columns: 1fr; }
  .diff-header, .diff-body { grid-template-columns: 1fr; }
  .diff-cell.right { border-left: none; border-top: 1px dashed var(--border); }
  .app-header { flex-direction: column; align-items: flex-start; }
}