:root {
  --bg: #0f172a;
  --panel: #1e293b;
  --panel-border: #334155;
  --text: #e2e8f0;
  --text-dim: #94a3b8;
  --accent: #3b82f6;
  --accent-hover: #2563eb;
  --danger: #ef4444;
  --radius: 10px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, "Segoe UI", "PingFang TC", "Microsoft JhengHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
}

.app {
  max-width: 960px;
  margin: 0 auto;
  padding: 24px 16px 64px;
}

header h1 { margin: 0 0 4px; font-size: 1.6rem; }
.subtitle { color: var(--text-dim); margin: 0 0 24px; font-size: 0.9rem; }

.panel {
  background: var(--panel);
  border: 1px solid var(--panel-border);
  border-radius: var(--radius);
  padding: 20px;
  margin-bottom: 20px;
}

.file-drop {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 140px;
  border: 2px dashed var(--panel-border);
  border-radius: var(--radius);
  cursor: pointer;
  text-align: center;
  color: var(--text-dim);
  transition: border-color 0.15s, color 0.15s, background 0.15s;
  padding: 16px;
}
.file-drop:hover, .file-drop.drag-over {
  border-color: var(--accent);
  color: var(--text);
  background: rgba(59, 130, 246, 0.08);
}

.options-row {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
  justify-content: space-between;
  align-items: flex-start;
}

.mode-select {
  border: none;
  padding: 0;
  margin: 0;
}
.mode-select legend {
  font-weight: 600;
  margin-bottom: 8px;
  padding: 0;
}
.mode-select label {
  display: block;
  margin-bottom: 6px;
  color: var(--text-dim);
  cursor: pointer;
}
.mode-select input { margin-right: 6px; }

.actions {
  display: flex;
  flex-direction: column;
  gap: 12px;
  align-items: flex-start;
}

.quick-rotate {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
  color: var(--text-dim);
  font-size: 0.85rem;
}

.btn {
  appearance: none;
  border: 1px solid var(--panel-border);
  background: #334155;
  color: var(--text);
  padding: 10px 16px;
  border-radius: 8px;
  cursor: pointer;
  font-size: 0.9rem;
  transition: background 0.15s, border-color 0.15s;
}
.btn:hover { background: #475569; }
.btn:disabled { opacity: 0.5; cursor: not-allowed; }
.btn.primary { background: var(--accent); border-color: var(--accent); }
.btn.primary:hover { background: var(--accent-hover); }
.btn.small { padding: 6px 10px; font-size: 0.8rem; }
.btn.large { width: 100%; padding: 14px; font-size: 1rem; }

.progress-wrap { margin-top: 16px; }
.progress-bar {
  height: 8px;
  background: #0b1220;
  border-radius: 4px;
  overflow: hidden;
  margin-bottom: 6px;
}
.progress-fill {
  height: 100%;
  width: 0%;
  background: var(--accent);
  transition: width 0.2s;
}
#progress-label { font-size: 0.8rem; color: var(--text-dim); }

.pages-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
  gap: 16px;
}

.page-card {
  background: #0b1220;
  border: 1px solid var(--panel-border);
  border-radius: 8px;
  padding: 10px;
  text-align: center;
}
.page-thumb-wrap {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 160px;
  overflow: hidden;
  margin-bottom: 8px;
}
.page-thumb-wrap canvas,
.page-thumb-wrap img {
  max-width: 100%;
  max-height: 100%;
  transition: transform 0.15s;
}
.page-label { font-size: 0.75rem; color: var(--text-dim); margin-bottom: 6px; }
.page-controls { display: flex; justify-content: center; gap: 6px; }
.page-controls .btn { padding: 4px 8px; font-size: 0.75rem; }

footer {
  margin-top: 32px;
  color: var(--text-dim);
  font-size: 0.8rem;
  text-align: center;
}
footer a { color: var(--text-dim); }

@media (max-width: 640px) {
  .options-row { flex-direction: column; }
}