:root {
  --slate: #475569;
  --slate-dark: #334155;
  --slate-light: #64748b;
  --green: #16a34a;
  --green-dark: #15803d;
  --green-soft: #dcfce7;

  --bg: #f1f5f9;
  --surface: #ffffff;
  --surface-2: #f8fafc;
  --text: #1e293b;
  --text-soft: #475569;
  --border: #cbd5e1;
  --border-soft: #e2e8f0;
  --danger: #dc2626;
  --danger-soft: #fee2e2;
  --shadow: 0 1px 3px rgba(15, 23, 42, .12), 0 1px 2px rgba(15, 23, 42, .08);
  --radius: 12px;
  --focus: 0 0 0 3px rgba(22, 163, 74, .45);
}

[data-theme="dark"] {
  --bg: #0f172a;
  --surface: #1e293b;
  --surface-2: #273449;
  --text: #e2e8f0;
  --text-soft: #cbd5e1;
  --border: #475569;
  --border-soft: #334155;
  --green-soft: #14532d;
  --danger-soft: #7f1d1d;
  --shadow: 0 1px 3px rgba(0, 0, 0, .45);
}

* { box-sizing: border-box; }

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

body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
  padding: env(safe-area-inset-top) env(safe-area-inset-right) env(safe-area-inset-bottom) env(safe-area-inset-left);
}

.skip-link {
  position: absolute;
  left: -999px;
  top: 0;
  background: var(--green);
  color: #fff;
  padding: .6rem 1rem;
  border-radius: 0 0 8px 0;
  z-index: 50;
}
.skip-link:focus { left: 0; }

/* Header */
.app-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  background: linear-gradient(135deg, var(--slate), var(--slate-dark));
  color: #fff;
  padding: 1rem clamp(1rem, 4vw, 2rem);
  flex-wrap: wrap;
}
.brand { display: flex; align-items: center; gap: .75rem; min-width: 0; }
.brand-icon { border-radius: 8px; flex: none; }
.app-header h1 { font-size: clamp(1.1rem, 4vw, 1.4rem); margin: 0; }
.tagline { margin: 0; font-size: .8rem; opacity: .85; }
.header-actions { display: flex; align-items: center; gap: .5rem; }

main {
  max-width: 880px;
  margin: 0 auto;
  padding: clamp(1rem, 4vw, 2rem);
  display: grid;
  gap: 1.25rem;
}

/* Notice */
.notice {
  background: var(--green-soft);
  border: 1px solid var(--green);
  color: var(--text);
  padding: .85rem 1rem;
  border-radius: var(--radius);
  font-size: .9rem;
  margin: 0;
}
[data-theme="dark"] .notice { color: var(--text); }

/* Cards */
.card {
  background: var(--surface);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: clamp(1rem, 3vw, 1.5rem);
}
.card h2 {
  margin: 0 0 1rem;
  font-size: 1.05rem;
  color: var(--slate);
  display: flex;
  align-items: center;
  gap: .5rem;
}
[data-theme="dark"] .card h2 { color: var(--text); }

/* Dropzone */
.dropzone {
  border: 2px dashed var(--border);
  border-radius: var(--radius);
  background: var(--surface-2);
  padding: clamp(1.25rem, 5vw, 2.25rem);
  text-align: center;
  cursor: pointer;
  color: var(--text-soft);
  transition: border-color .15s, background .15s, transform .15s;
}
.dropzone:hover { border-color: var(--green); }
.dropzone:focus-visible { outline: none; box-shadow: var(--focus); border-color: var(--green); }
.dropzone.dragover {
  border-color: var(--green);
  background: var(--green-soft);
  transform: scale(1.01);
}
.drop-illu { color: var(--slate); margin-bottom: .25rem; }
[data-theme="dark"] .drop-illu { color: var(--green); }
.drop-main { margin: .25rem 0 0; font-weight: 600; color: var(--text); }
.drop-sub { margin: .2rem 0 0; font-size: .85rem; }

.file-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  margin-top: .85rem;
  font-size: .9rem;
  flex-wrap: wrap;
}

/* Form */
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 1rem;
}
.field { display: flex; flex-direction: column; gap: .35rem; }
.field label { font-weight: 600; font-size: .88rem; }
.field-group {
  border: 1px solid var(--border-soft);
  border-radius: var(--radius);
  padding: 1rem;
  margin: 1.25rem 0 0;
  display: grid;
  gap: .85rem;
}
.field-group legend {
  font-weight: 700;
  color: var(--slate);
  padding: 0 .4rem;
  font-size: .9rem;
}
[data-theme="dark"] .field-group legend { color: var(--text); }

input[type="text"],
input[type="number"],
select {
  width: 100%;
  font: inherit;
  padding: .55rem .7rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--surface-2);
  color: var(--text);
}
input[type="text"]:focus-visible,
input[type="number"]:focus-visible,
select:focus-visible {
  outline: none;
  border-color: var(--green);
  box-shadow: var(--focus);
}

.check {
  display: flex;
  align-items: center;
  gap: .55rem;
  font-size: .9rem;
  cursor: pointer;
}
.check input { width: 1.1rem; height: 1.1rem; accent-color: var(--green); flex: none; }
.check input:focus-visible { outline: none; box-shadow: var(--focus); border-radius: 4px; }

.hint { font-size: .82rem; color: var(--text-soft); margin: 0; }

.form-actions {
  display: flex;
  gap: .75rem;
  margin-top: 1.25rem;
  flex-wrap: wrap;
}

/* Buttons */
.btn {
  font: inherit;
  font-weight: 600;
  border: 1px solid transparent;
  border-radius: 8px;
  padding: .6rem 1.1rem;
  cursor: pointer;
  background: var(--surface-2);
  color: var(--text);
  transition: background .15s, transform .05s, box-shadow .15s;
}
.btn:active { transform: translateY(1px); }
.btn:focus-visible { outline: none; box-shadow: var(--focus); }
.btn:disabled { opacity: .5; cursor: not-allowed; }

.btn-primary { background: var(--green); color: #fff; border-color: var(--green-dark); }
.btn-primary:hover:not(:disabled) { background: var(--green-dark); }

.btn-ghost { background: transparent; border-color: var(--border); color: var(--text-soft); }
.btn-ghost:hover:not(:disabled) { background: var(--surface-2); color: var(--text); }

.btn-block { width: 100%; }

.btn-icon {
  background: rgba(255, 255, 255, .15);
  color: #fff;
  border-color: rgba(255, 255, 255, .3);
  padding: .5rem .65rem;
  line-height: 1;
}
.btn-icon:hover { background: rgba(255, 255, 255, .28); }
.header-actions .btn-ghost {
  background: rgba(255, 255, 255, .15);
  color: #fff;
  border-color: rgba(255, 255, 255, .3);
}
.header-actions .btn-ghost:hover { background: rgba(255, 255, 255, .28); color: #fff; }

.theme-icon { font-size: 1.1rem; }

/* Conflict banner */
.conflict-banner {
  background: var(--danger-soft);
  border: 1px solid var(--danger);
  color: var(--text);
  padding: .65rem .9rem;
  border-radius: 8px;
  font-size: .88rem;
  margin: 0 0 1rem;
}

/* Table */
.table-wrap { overflow-x: auto; -webkit-overflow-scrolling: touch; }
.preview-table {
  width: 100%;
  border-collapse: collapse;
  font-size: .88rem;
  table-layout: fixed;
}
.preview-table th,
.preview-table td {
  text-align: left;
  padding: .55rem .6rem;
  border-bottom: 1px solid var(--border-soft);
  vertical-align: top;
  overflow-wrap: anywhere;
  word-break: break-word;
}
.preview-table thead th {
  color: var(--text-soft);
  font-size: .78rem;
  text-transform: uppercase;
  letter-spacing: .03em;
  border-bottom: 2px solid var(--border);
}
.col-order { width: 3rem; }
.col-move { width: 5.5rem; }
.preview-table .new-name { color: var(--green-dark); font-weight: 600; }
[data-theme="dark"] .preview-table .new-name { color: #4ade80; }
.preview-table tr.conflict td { background: var(--danger-soft); }
.preview-table tr.conflict .new-name { color: var(--danger); }
.empty-row td { text-align: center; color: var(--text-soft); padding: 1.5rem; }

.conflict-tag {
  display: inline-block;
  font-size: .72rem;
  font-weight: 700;
  color: #fff;
  background: var(--danger);
  border-radius: 4px;
  padding: .05rem .35rem;
  margin-left: .35rem;
  vertical-align: middle;
}

.move-cell { display: flex; gap: .3rem; }
.move-btn {
  font: inherit;
  border: 1px solid var(--border);
  background: var(--surface-2);
  color: var(--text);
  border-radius: 6px;
  width: 2rem;
  height: 2rem;
  cursor: pointer;
  line-height: 1;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}
.move-btn:hover:not(:disabled) { border-color: var(--green); color: var(--green); }
.move-btn:focus-visible { outline: none; box-shadow: var(--focus); }
.move-btn:disabled { opacity: .35; cursor: not-allowed; }
.row-remove {
  border: none;
  background: transparent;
  color: var(--danger);
  cursor: pointer;
  font-size: 1rem;
  padding: .1rem .35rem;
  border-radius: 6px;
}
.row-remove:hover { background: var(--danger-soft); }
.row-remove:focus-visible { outline: none; box-shadow: var(--focus); }

.old-name-cell { display: flex; align-items: flex-start; justify-content: space-between; gap: .4rem; }

/* Footer */
.app-footer {
  text-align: center;
  color: var(--text-soft);
  font-size: .82rem;
  padding: .5rem 0 1rem;
}

/* Toast */
.toast-wrap {
  position: fixed;
  left: 50%;
  bottom: calc(1rem + env(safe-area-inset-bottom));
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  gap: .5rem;
  z-index: 100;
  width: min(92vw, 420px);
  pointer-events: none;
}
.toast {
  background: var(--slate-dark);
  color: #fff;
  padding: .7rem 1rem;
  border-radius: 10px;
  box-shadow: 0 6px 20px rgba(0, 0, 0, .3);
  font-size: .9rem;
  animation: toast-in .2s ease;
}
.toast.toast-success { background: var(--green-dark); }
.toast.toast-error { background: var(--danger); }

@keyframes toast-in {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Utilities */
.visually-hidden,
.btn[hidden] { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0; }
.btn[hidden] { display: none; }
[hidden] { display: none !important; }

@media (max-width: 480px) {
  .form-actions .btn { flex: 1 1 auto; }
  .preview-table { font-size: .82rem; }
  .col-move { width: 4.5rem; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
  }
}