:root {
  --bg: #f5f6f8;
  --surface: #ffffff;
  --text: #1c1f24;
  --muted: #5f6672;
  --border: #d9dde3;
  --primary: #2357d9;
  --primary-hover: #1b47b5;
  --primary-text: #ffffff;
  --focus: #2357d9;
  --error-bg: #fdecec;
  --error-text: #a3201b;
  --warn-bg: #fff6e0;
  --warn-text: #7a5400;
  --info-bg: #e9f0ff;
  --info-text: #1b3f99;
  --checker-a: #e6e8ec;
  --checker-b: #ffffff;
  --radius: 10px;
  color-scheme: light dark;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #15171b;
    --surface: #1f2228;
    --text: #e8eaee;
    --muted: #a0a7b3;
    --border: #353a43;
    --primary: #5b8cff;
    --primary-hover: #7aa2ff;
    --primary-text: #0d1120;
    --focus: #7aa2ff;
    --error-bg: #3a1a1a;
    --error-text: #ffb3ad;
    --warn-bg: #3a2f12;
    --warn-text: #ffd98a;
    --info-bg: #18264a;
    --info-text: #b8ccff;
    --checker-a: #2a2e35;
    --checker-b: #353a43;
  }
}

*, *::before, *::after { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, "Segoe UI", "Noto Sans TC", "PingFang TC", "Microsoft JhengHei", sans-serif;
  font-size: 16px;
  line-height: 1.55;
  overflow-x: hidden;
}

.page {
  max-width: 880px;
  margin: 0 auto;
  padding: 24px 16px 48px;
}

.page-header h1 { font-size: 1.5rem; margin: 0 0 4px; }
.page-header p { margin: 0 0 16px; }
.page-footer { margin-top: 24px; }

h2 { font-size: 1.1rem; margin: 0 0 12px; }

.muted { color: var(--muted); }
.small { font-size: 0.875rem; }
.break { overflow-wrap: anywhere; word-break: break-word; }

.visually-hidden {
  position: absolute !important;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0 0 0 0);
  white-space: nowrap; border: 0;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  margin-bottom: 16px;
  min-width: 0;
}

/* 上傳區 */
.drop-zone {
  border: 2px dashed var(--border);
  border-radius: var(--radius);
  padding: 28px 16px;
  text-align: center;
  transition: border-color 0.15s, background-color 0.15s;
}
.drop-zone p { margin: 4px 0; }
.drop-zone .drop-title { font-weight: 600; font-size: 1.05rem; }
.drop-zone.is-dragover { border-color: var(--primary); background: var(--info-bg); }
.drop-zone.is-busy { opacity: 0.6; }

/* 狀態列 */
.status {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-top: 12px;
  color: var(--muted);
  min-height: 1.5em;
}
.spinner {
  display: none;
  width: 16px; height: 16px;
  border: 2px solid var(--border);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  flex: none;
}
.status.is-busy .spinner { display: inline-block; }
.status.is-done { color: var(--text); }
@keyframes spin { to { transform: rotate(360deg); } }
@media (prefers-reduced-motion: reduce) { .spinner { animation-duration: 2s; } }

/* 訊息 */
.alert {
  border-radius: 8px;
  padding: 10px 12px;
  margin: 12px 0 0;
  overflow-wrap: anywhere;
}
.alert-error { background: var(--error-bg); color: var(--error-text); }
.alert-warn { background: var(--warn-bg); color: var(--warn-text); }
.alert-info { background: var(--info-bg); color: var(--info-text); }
[hidden] { display: none !important; }

/* 預覽與資訊 */
.media-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 20px;
  align-items: start;
}
@media (max-width: 640px) {
  .media-row { grid-template-columns: minmax(0, 1fr); }
}
.preview-box {
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 8px;
  min-height: 120px;
  max-height: 360px;
  overflow: hidden;
  background-color: var(--checker-b);
  background-image:
    linear-gradient(45deg, var(--checker-a) 25%, transparent 25%),
    linear-gradient(-45deg, var(--checker-a) 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, var(--checker-a) 75%),
    linear-gradient(-45deg, transparent 75%, var(--checker-a) 75%);
  background-size: 16px 16px;
  background-position: 0 0, 0 8px, 8px -8px, -8px 0;
}
.preview {
  display: block;
  max-width: 100%;
  max-height: 340px;
  width: auto;
  height: auto;
  object-fit: contain;
}

.info-list { margin: 0; display: grid; gap: 6px; }
.info-list > div { display: grid; grid-template-columns: 4em minmax(0, 1fr); gap: 8px; }
.info-list dt { color: var(--muted); }
.info-list dd { margin: 0; font-variant-numeric: tabular-nums; }

/* 表單 */
form { margin: 0; }
.group { border: 0; padding: 0; margin: 0 0 20px; min-width: 0; }
.group legend { font-weight: 600; padding: 0; margin-bottom: 8px; }
.field { min-width: 0; }
.field label { display: block; font-size: 0.9rem; margin-bottom: 4px; }

.size-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr);
  gap: 10px;
  align-items: start;
}

input[type="text"] {
  width: 100%;
  font: inherit;
  font-size: 1.1rem;
  font-variant-numeric: tabular-nums;
  padding: 10px 12px;
  color: var(--text);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
}
input[type="text"][aria-invalid="true"] { border-color: var(--error-text); }
.field-error { color: var(--error-text); font-size: 0.85rem; margin: 4px 0 0; min-height: 1.2em; }

.lock-button {
  margin-top: 28px;
  width: 44px; height: 44px;
  display: inline-flex; align-items: center; justify-content: center;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--surface);
  color: var(--muted);
  cursor: pointer;
}
.lock-button[aria-pressed="true"] { color: var(--primary); border-color: var(--primary); }
.lock-button .icon-unlocked { display: none; }
.lock-button[aria-pressed="false"] .icon-locked { display: none; }
.lock-button[aria-pressed="false"] .icon-unlocked { display: inline; }

.presets { display: flex; flex-wrap: wrap; align-items: center; gap: 8px; margin-top: 12px; }

.format-options { display: flex; flex-wrap: wrap; gap: 8px; }
.format-option {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 8px 14px;
  border: 1px solid var(--border);
  border-radius: 8px;
  cursor: pointer;
}
.format-option:has(input:checked) { border-color: var(--primary); background: var(--info-bg); }
.format-option:has(input:disabled) { opacity: 0.5; cursor: not-allowed; }
.format-option input { margin: 0; }

.quality-field, .background-field { margin-top: 14px; }
input[type="range"] { width: 100%; max-width: 420px; }
.color-row { display: flex; align-items: center; gap: 10px; }
input[type="color"] { width: 48px; height: 36px; padding: 2px; border: 1px solid var(--border); border-radius: 6px; background: var(--surface); }

/* 按鈕 */
.button {
  display: inline-flex; align-items: center; justify-content: center;
  font: inherit;
  padding: 8px 16px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  text-decoration: none;
  cursor: pointer;
  min-height: 40px;
}
.button:hover { border-color: var(--primary); }
.button-primary { background: var(--primary); color: var(--primary-text); border-color: var(--primary); font-weight: 600; }
.button-primary:hover { background: var(--primary-hover); border-color: var(--primary-hover); }
.button-small { padding: 4px 12px; min-height: 36px; font-variant-numeric: tabular-nums; }
.button-large { padding: 12px 28px; font-size: 1.05rem; }
.button:disabled, .button[aria-disabled="true"] { opacity: 0.5; cursor: not-allowed; pointer-events: none; }
.actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 8px; }

:focus-visible { outline: 3px solid var(--focus); outline-offset: 2px; }

/* ---------- 多張圖片（輪播） ---------- */
.section-head { display: flex; align-items: center; justify-content: space-between; gap: 12px; margin-bottom: 12px; }
.section-head h2 { margin: 0; }
.button-quiet { background: transparent; }

.carousel { min-width: 0; outline: none; border-radius: 8px; }
.carousel:focus-visible { outline: 3px solid var(--focus); outline-offset: 2px; }

/* 固定高度的舞台：不同比例的圖片切換時版面不跳動 */
.stage {
  position: relative;
  height: 300px;
  max-height: none;
  touch-action: pan-y;
  user-select: none;
  -webkit-user-select: none;
}
.stage .preview {
  width: 100%;
  height: 100%;
  max-height: none;
  object-fit: contain;
}
.stage .preview:not([src]) { visibility: hidden; }
.stage-note {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 12px;
  background: color-mix(in srgb, var(--surface) 70%, transparent);
}
@media (max-width: 640px) { .stage { height: 240px; } }

.carousel-bar {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  margin-top: 8px;
}
.nav-button {
  width: 44px;
  height: 36px;
  font-size: 1.4rem;
  line-height: 1;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--surface);
  color: var(--text);
  cursor: pointer;
}
.nav-button:hover { border-color: var(--primary); }
.nav-button:disabled { opacity: 0.4; cursor: default; }
.position { min-width: 5em; text-align: center; font-variant-numeric: tabular-nums; color: var(--muted); }

.info-col { min-width: 0; }
.info-col .actions { margin-top: 12px; }

.presets .button[aria-pressed="true"] { border-color: var(--primary); background: var(--info-bg); color: var(--info-text); }

/* ---------- 結果 ---------- */
.batch-progress {
  margin: 0 0 12px;
  padding: 10px 12px;
  border-radius: 8px;
  background: var(--info-bg);
  color: var(--info-text);
  font-variant-numeric: tabular-nums;
}
.item-status { margin: 0 0 8px; font-weight: 600; }
.item-status.is-ok { color: var(--text); }
.item-status.is-error { color: var(--error-text); }
.item-status.is-pending { color: var(--muted); font-weight: normal; }

.bulk-actions { border-top: 1px solid var(--border); margin-top: 16px; padding-top: 12px; }
.bulk-actions p { margin: 0 0 8px; }
.stage.is-stale .preview { opacity: 0.45; }

#loadError { white-space: pre-line; }