*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --accent: #e8192c;
  --accent-hover: #c8152a;
  --accent-light: #fff0f1;
  --border: #dde1e7;
  --bg: #f5f7fa;
  --card-bg: #ffffff;
  --text: #1a1a2e;
  --text-muted: #6b7280;
  --radius: 12px;
  --shadow: 0 2px 12px rgba(0,0,0,0.08);
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Hiragino Sans', sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* ── Header ── */
header {
  background: #fff;
  border-bottom: 1px solid var(--border);
  padding: 24px 20px;
}

.header-inner {
  max-width: 860px;
  margin: 0 auto;
  text-align: center;
}

h1 {
  font-size: 2rem;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: -0.5px;
}

h1 .arrow {
  color: var(--text);
  font-weight: 300;
}

header p {
  margin-top: 6px;
  color: var(--text-muted);
  font-size: 0.875rem;
}

/* ── Main ── */
main {
  flex: 1;
  max-width: 860px;
  width: 100%;
  margin: 32px auto;
  padding: 0 16px;
}

/* ── Drop Zone ── */
.drop-zone {
  background: var(--card-bg);
  border: 2.5px dashed var(--border);
  border-radius: var(--radius);
  padding: 52px 20px;
  text-align: center;
  cursor: pointer;
  transition: border-color 0.2s, background 0.2s;
}

.drop-zone:hover,
.drop-zone.drag-over {
  border-color: var(--accent);
  background: var(--accent-light);
}

.drop-zone-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
}

.drop-icon {
  width: 56px;
  height: 56px;
  color: var(--accent);
  margin-bottom: 4px;
}

.drop-text {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text);
}

.drop-subtext {
  color: var(--text-muted);
  font-size: 0.875rem;
}

.btn-select {
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 8px;
  padding: 10px 28px;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s;
  margin-top: 4px;
}

.btn-select:hover {
  background: var(--accent-hover);
}

.drop-hint {
  color: var(--text-muted);
  font-size: 0.78rem;
  margin-top: 4px;
}

/* ── Workspace ── */
.workspace {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.workspace.hidden {
  display: none;
}

/* ── File List ── */
.file-list {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 14px;
}

.file-card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 10px;
  overflow: hidden;
  box-shadow: var(--shadow);
  position: relative;
  cursor: grab;
  transition: transform 0.15s, box-shadow 0.15s;
  user-select: none;
}

.file-card:active {
  cursor: grabbing;
}

.file-card.sortable-ghost {
  opacity: 0.35;
}

.file-card.sortable-chosen {
  transform: scale(1.03);
  box-shadow: 0 6px 24px rgba(0,0,0,0.14);
}

.file-card-thumb {
  width: 100%;
  aspect-ratio: 1;
  object-fit: cover;
  display: block;
  background: #f0f0f0;
}

.file-card-info {
  padding: 8px 10px;
}

.file-card-name {
  font-size: 0.75rem;
  color: var(--text-muted);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.file-card-num {
  position: absolute;
  top: 7px;
  left: 8px;
  background: rgba(0,0,0,0.55);
  color: #fff;
  font-size: 0.7rem;
  font-weight: 700;
  padding: 2px 7px;
  border-radius: 20px;
}

.file-card-delete {
  position: absolute;
  top: 6px;
  right: 7px;
  background: rgba(0,0,0,0.55);
  color: #fff;
  border: none;
  border-radius: 50%;
  width: 22px;
  height: 22px;
  font-size: 14px;
  line-height: 1;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.15s;
}

.file-card-delete:hover {
  background: var(--accent);
}

/* ── Add More ── */
.add-more-row {
  display: flex;
  justify-content: flex-start;
}

.btn-add-more {
  background: transparent;
  border: 2px dashed var(--border);
  border-radius: 8px;
  padding: 9px 22px;
  font-size: 0.9rem;
  color: var(--text-muted);
  cursor: pointer;
  transition: border-color 0.15s, color 0.15s;
}

.btn-add-more:hover {
  border-color: var(--accent);
  color: var(--accent);
}

/* ── Options Panel ── */
.options-panel {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px 24px;
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
}

.option-group {
  display: flex;
  flex-direction: column;
  gap: 8px;
  flex: 1;
  min-width: 180px;
}

.option-label {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.option-buttons {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
}

.opt-btn {
  background: #f3f4f6;
  border: 1.5px solid var(--border);
  border-radius: 7px;
  padding: 7px 14px;
  font-size: 0.85rem;
  color: var(--text);
  cursor: pointer;
  transition: all 0.15s;
  display: flex;
  align-items: center;
  gap: 5px;
}

.opt-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.opt-btn.active {
  background: var(--accent-light);
  border-color: var(--accent);
  color: var(--accent);
  font-weight: 600;
}

/* portrait / landscape icons */
.icon-portrait,
.icon-landscape {
  display: inline-block;
  border: 1.5px solid currentColor;
  border-radius: 2px;
}

.icon-portrait {
  width: 9px;
  height: 13px;
}

.icon-landscape {
  width: 13px;
  height: 9px;
}

/* ── Convert Button ── */
.convert-row {
  display: flex;
  justify-content: center;
}

.btn-convert {
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 10px;
  padding: 15px 52px;
  font-size: 1.05rem;
  font-weight: 700;
  cursor: pointer;
  transition: background 0.15s, transform 0.1s;
  min-width: 200px;
}

.btn-convert:hover:not(:disabled) {
  background: var(--accent-hover);
}

.btn-convert:active:not(:disabled) {
  transform: scale(0.98);
}

.btn-convert:disabled {
  opacity: 0.65;
  cursor: not-allowed;
}

.btn-convert.loading::after {
  content: '';
  display: inline-block;
  width: 14px;
  height: 14px;
  border: 2px solid rgba(255,255,255,0.4);
  border-top-color: #fff;
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
  margin-left: 10px;
  vertical-align: middle;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* ── Status ── */
.status {
  text-align: center;
  padding: 14px 20px;
  border-radius: 8px;
  font-size: 0.95rem;
  font-weight: 500;
}

.status.hidden {
  display: none;
}

.status.success {
  background: #ecfdf5;
  color: #065f46;
  border: 1px solid #a7f3d0;
}

.status.error {
  background: #fff0f1;
  color: #9b1c1c;
  border: 1px solid #fca5a5;
}

/* ── Footer ── */
footer {
  text-align: center;
  padding: 20px;
  color: var(--text-muted);
  font-size: 0.8rem;
  border-top: 1px solid var(--border);
  background: #fff;
}

/* ── Hidden utility ── */
.hidden {
  display: none !important;
}

/* ── Responsive ── */
@media (max-width: 600px) {
  h1 { font-size: 1.5rem; }

  .drop-zone { padding: 36px 16px; }

  .file-list {
    grid-template-columns: repeat(auto-fill, minmax(110px, 1fr));
  }

  .options-panel {
    padding: 16px;
    flex-direction: column;
  }

  .btn-convert {
    width: 100%;
    padding: 14px;
  }
}