:root {
  color-scheme: light dark;
  --bg: #f5f6f8;
  --panel: #ffffff;
  --border: #d9dce1;
  --text: #1c1f24;
  --muted: #6b7280;
  --accent: #3562ff;
  --danger: #e0433d;
  --add: #1f9d55;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #14161a;
    --panel: #1e2126;
    --border: #33373f;
    --text: #ecedee;
    --muted: #9aa0aa;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: "Segoe UI", "Hiragino Sans", "Noto Sans JP", system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
}

.app-header {
  padding: 24px 32px 8px;
}

.app-header h1 {
  margin: 0;
  font-size: 1.6rem;
}

.subtitle {
  color: var(--muted);
  margin: 4px 0 0;
  font-size: 0.9rem;
}

main {
  max-width: 1100px;
  margin: 0 auto;
  padding: 16px 32px 48px;
}

.upload-panel {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  align-items: stretch;
  margin-bottom: 20px;
}

.drop-zone {
  flex: 1 1 260px;
  background: var(--panel);
  border: 1px dashed var(--border);
  border-radius: 10px;
  padding: 16px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.drop-zone label {
  font-weight: 600;
}

.file-name {
  font-size: 0.85rem;
  color: var(--muted);
  word-break: break-all;
}

button {
  cursor: pointer;
  border: none;
  border-radius: 8px;
  padding: 10px 18px;
  font-size: 0.95rem;
  background: var(--accent);
  color: white;
  transition: opacity 0.15s;
}

button:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

button:not(:disabled):hover {
  opacity: 0.9;
}

#compareBtn {
  align-self: center;
}

.status {
  padding: 12px 16px;
  border-radius: 8px;
  background: var(--panel);
  border: 1px solid var(--border);
  margin-bottom: 16px;
  font-size: 0.9rem;
}

.controls {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 16px;
}

.view-mode {
  display: flex;
  gap: 12px;
  margin-left: auto;
  font-size: 0.85rem;
  flex-wrap: wrap;
}

.view-mode label {
  display: flex;
  align-items: center;
  gap: 4px;
}

.result {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 16px;
}

.canvas-wrap h3 {
  margin: 0 0 8px;
  font-size: 0.9rem;
  color: var(--muted);
}

.side-by-side-view {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

canvas {
  max-width: 100%;
  border: 1px solid var(--border);
  border-radius: 4px;
  background: white;
}

.text-view pre {
  white-space: pre-wrap;
  word-break: break-word;
  font-size: 0.85rem;
  line-height: 1.6;
}

.diff-del {
  background: rgba(224, 67, 61, 0.25);
  color: var(--danger);
  text-decoration: line-through;
}

.diff-add {
  background: rgba(31, 157, 85, 0.25);
  color: var(--add);
}

.legend-del { color: var(--danger); font-weight: 600; }
.legend-add { color: var(--add); font-weight: 600; }