:root {
  --color-paper: #f4f1e8;
  --color-paper-deep: #ece7d9;
  --color-ink: #1c1b18;
  --color-ink-soft: #6b665b;
  --color-line: #d9d3c3;
  --color-accent: #d8442a;
  --color-accent-deep: #b0331d;
  --color-mark: #e0a92e;
  --font-display: Inter, Noto Sans TC, sans-serif;
  --font-body: Inter, Noto Sans TC, sans-serif;
  --font-mono: Inter, Noto Sans TC, sans-serif;
  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
}

.tool-intro {
  max-width: 68ch;
  margin-block: 24px 40px;
  color: #6b665b;
}

.diff-tool {
  max-width: 100%;
}

.diff-controls {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 8px;
  margin-bottom: 24px;
}

.diff-columns {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  margin-bottom: 24px;
}

.editor-pane {
  display: flex;
  flex-direction: column;
  gap: 16px;
  min-width: 0;
}

.editor-toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
}

.editor-toolbar-label {
  font-family: "Inter", "Noto Sans TC", sans-serif;
  font-size: 1rem;
  letter-spacing: 0.04em;
  color: #6b665b;
  font-variant-numeric: tabular-nums;
}

.text-area {
  width: 100%;
  min-height: 280px;
  padding: 24px;
  font-family: "Inter", "Noto Sans TC", sans-serif;
  font-size: 1rem;
  line-height: 1.85;
  color: #1c1b18;
  background: #f4f1e8;
  border: 1.5px solid #1c1b18;
  border-radius: 2px;
  box-shadow: 6px 6px 0 rgba(28, 27, 24, 0.12);
  resize: vertical;
  transition: border-color 0.4s cubic-bezier(0.22, 0.61, 0.36, 1);
}
.text-area::placeholder {
  color: #6b665b;
}
.text-area:focus {
  outline: none;
  border-color: #d8442a;
}

.copy-hint {
  min-height: 1.4em;
  margin: 8px 0 0;
  font-family: "Inter", "Noto Sans TC", sans-serif;
  font-size: 1rem;
  color: #d8442a;
}

.unit-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 24px;
}

.unit-tab {
  font-family: "Inter", "Noto Sans TC", sans-serif;
  font-size: 1rem;
  letter-spacing: 0.04em;
  padding: 8px 16px;
  color: #6b665b;
  background: #f4f1e8;
  border: 1px solid #d9d3c3;
  border-radius: 2px;
  cursor: pointer;
  transition: color 0.4s cubic-bezier(0.22, 0.61, 0.36, 1), border-color 0.4s cubic-bezier(0.22, 0.61, 0.36, 1), background-color 0.4s cubic-bezier(0.22, 0.61, 0.36, 1);
}
.unit-tab:hover {
  color: #1c1b18;
  border-color: #1c1b18;
}
.unit-tab.is-active {
  color: #f4f1e8;
  background: #d8442a;
  border-color: #d8442a;
}

.diff-result-head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 16px;
}

.diff-stat {
  display: flex;
  flex-wrap: wrap;
  gap: 24px;
  margin: 0;
  font-family: "Inter", "Noto Sans TC", sans-serif;
  font-size: 1rem;
  letter-spacing: 0.03em;
}

.diff-stat-add {
  color: #d8442a;
}

.diff-stat-del {
  color: #e0a92e;
}

.diff-result {
  border: 1.5px solid #1c1b18;
  border-radius: 2px;
  background: #f4f1e8;
  overflow: auto;
  max-height: 640px;
}

.diff-empty {
  margin: 0;
  padding: 40px 24px;
  text-align: center;
  font-family: "Inter", "Noto Sans TC", sans-serif;
  font-size: 1rem;
  color: #6b665b;
}

.diff-line {
  display: grid;
  grid-template-columns: 96px 1.5em 1fr;
  align-items: start;
  font-family: "Inter", "Noto Sans TC", sans-serif;
  font-size: 1rem;
  line-height: 1.7;
  border-bottom: 1px solid rgba(28, 27, 24, 0.06);
}
.diff-line:last-child {
  border-bottom: 0;
}
.diff-line[data-type=add] {
  background: color-mix(in srgb, #d8442a 10%, #f4f1e8);
}
.diff-line[data-type=del] {
  background: color-mix(in srgb, #e0a92e 16%, #f4f1e8);
}

.diff-gutter {
  display: flex;
  gap: 4px;
  padding: 2px 8px;
  color: #6b665b;
  font-variant-numeric: tabular-nums;
  user-select: none;
  border-right: 1px solid #d9d3c3;
}

.diff-gutter-old,
.diff-gutter-new {
  width: 2.4em;
  text-align: right;
}

.diff-marker {
  padding: 2px 0;
  text-align: center;
  user-select: none;
  color: #6b665b;
}

.diff-line[data-type=add] .diff-marker {
  color: #d8442a;
}

.diff-line[data-type=del] .diff-marker {
  color: #e0a92e;
}

.diff-content {
  padding: 2px 8px 2px 0;
  white-space: pre-wrap;
  word-break: break-word;
  color: #1c1b18;
}

.diff-line[data-type=del] .diff-content {
  color: #6b665b;
  text-decoration: line-through;
  text-decoration-color: color-mix(in srgb, #e0a92e 70%, #1c1b18);
}

.diff-charflow {
  padding: 24px;
  font-family: "Inter", "Noto Sans TC", sans-serif;
  font-size: 1rem;
  line-height: 1.85;
  white-space: pre-wrap;
  word-break: break-word;
  color: #1c1b18;
}

.diff-run[data-type=add] {
  background: color-mix(in srgb, #d8442a 18%, transparent);
  color: #b0331d;
  text-decoration: underline;
  text-decoration-color: #d8442a;
}

.diff-run[data-type=del] {
  background: color-mix(in srgb, #e0a92e 22%, transparent);
  color: #6b665b;
  text-decoration: line-through;
}

@media (max-width: 760px) {
  .diff-columns {
    grid-template-columns: minmax(0, 1fr);
  }
  .text-area {
    min-height: 220px;
  }
  .diff-line {
    grid-template-columns: 72px 1.25em 1fr;
  }
  .diff-gutter-old,
  .diff-gutter-new {
    width: 2em;
  }
}