:root {
  --bg: #f6f8fa;
  --panel: #ffffff;
  --ink: #1c2530;
  --muted: #5b6b7b;
  --accent: #0e7a5f;
  --accent-dark: #0a5d49;
  --accent-soft: #e3f3ee;
  --border: #dde4ea;
  --error: #c0392b;
  --radius: 12px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.55;
}

.site-header {
  display: flex;
  align-items: center;
  padding: 14px 24px;
  background: var(--panel);
  border-bottom: 1px solid var(--border);
  flex-wrap: wrap;
  gap: 10px 24px;
}
/* brand + nav sit together on the left; pill + language picker group right */
.privacy-pill { margin-left: auto; }

.brand { display: flex; align-items: center; gap: 8px; font-weight: 700; font-size: 18px; color: inherit; text-decoration: none; }
.brand-mark { font-size: 20px; }

.tool-nav { display: flex; gap: 4px; flex-wrap: wrap; }
.tool-nav a {
  color: var(--muted);
  text-decoration: none;
  font-size: 14px;
  font-weight: 600;
  padding: 5px 12px;
  border-radius: 999px;
}
.tool-nav a:hover { color: var(--ink); background: var(--bg); }
.tool-nav a.active { color: var(--accent-dark); background: var(--accent-soft); }

.privacy-pill {
  font-size: 13px;
  background: var(--accent-soft);
  color: var(--accent-dark);
  border: 1px solid var(--accent);
  padding: 4px 12px;
  border-radius: 999px;
  font-weight: 600;
}

main { max-width: 760px; margin: 0 auto; padding: 32px 20px 64px; }

.hero { text-align: center; margin-bottom: 28px; }
.hero h1 { font-size: 36px; margin: 0 0 8px; }
.hero .sub { color: var(--muted); max-width: 560px; margin: 0 auto; font-size: 16px; }

.panel {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  margin-bottom: 28px;
}

/* Dropzone */
.dropzone {
  border: 2px dashed var(--border);
  border-radius: var(--radius);
  padding: 48px 24px;
  text-align: center;
  transition: border-color 0.15s, background 0.15s;
  cursor: pointer;
}
.dropzone.dragover { border-color: var(--accent); background: var(--accent-soft); }
.dropzone-icon { font-size: 40px; margin-bottom: 12px; }
.drop-hint { color: var(--muted); margin: 12px 0 0; font-size: 14px; }

/* Buttons */
.btn {
  display: inline-block;
  border: none;
  border-radius: 8px;
  padding: 10px 22px;
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
  text-decoration: none;
  font-family: inherit;
}
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: var(--accent-dark); }
.btn-big { width: 100%; padding: 14px; font-size: 17px; margin-top: 18px; text-align: center; }
.btn-ghost {
  background: transparent;
  color: var(--muted);
  border: 1px solid var(--border);
}
.btn-ghost:hover { color: var(--ink); border-color: var(--muted); }

/* File info */
.file-info {
  display: flex;
  align-items: center;
  gap: 12px;
  padding-bottom: 18px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 18px;
}
.file-icon { font-size: 28px; }
.file-name { font-weight: 600; word-break: break-all; }
.file-meta { color: var(--muted); font-size: 13px; }
.file-info .btn-ghost { margin-left: auto; white-space: nowrap; }

/* Tabs */
.tabs { display: flex; gap: 8px; margin-bottom: 18px; }
.tab {
  flex: 1;
  padding: 10px;
  border: 1px solid var(--border);
  background: var(--bg);
  border-radius: 8px;
  font-size: 15px;
  font-weight: 600;
  color: var(--muted);
  cursor: pointer;
  font-family: inherit;
}
.tab.active { background: var(--accent-soft); border-color: var(--accent); color: var(--accent-dark); }

.mode-switch { display: flex; gap: 20px; margin-bottom: 16px; }
.radio, .check { display: flex; align-items: center; gap: 7px; font-size: 15px; cursor: pointer; }
.check { margin-top: 14px; }

/* Range rows */
.range-row {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 10px;
  flex-wrap: wrap;
}
.range-row .range-label { font-weight: 600; font-size: 14px; color: var(--muted); min-width: 64px; }
.range-row input[type="number"] {
  width: 90px;
  padding: 8px 10px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 15px;
  font-family: inherit;
}
.range-row .remove-range {
  background: none;
  border: none;
  color: var(--muted);
  font-size: 16px;
  cursor: pointer;
  padding: 4px 8px;
}
.range-row .remove-range:hover { color: var(--error); }

.field-label { display: block; font-weight: 600; font-size: 14px; margin-bottom: 6px; }
.inline-field { display: flex; align-items: center; gap: 8px; }
.inline-field input {
  width: 90px;
  padding: 8px 10px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 15px;
  font-family: inherit;
}
.text-input {
  width: 100%;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 15px;
  font-family: inherit;
}

.hint { color: var(--muted); font-size: 14px; margin: 10px 0 0; }
.error { color: var(--error); font-size: 14px; font-weight: 600; margin: 12px 0 0; }

/* Result */
#result-panel { text-align: center; }
.result-icon { font-size: 44px; }
#result-panel h2 { margin: 8px 0 4px; }
#again-btn { margin-top: 14px; }

/* Landing tool cards */
.tools-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
  margin-bottom: 12px;
}
@media (max-width: 560px) {
  .tools-grid { grid-template-columns: 1fr; }
}
.tool-card {
  display: block;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px;
  text-decoration: none;
  color: inherit;
  transition: border-color 0.15s, transform 0.1s, box-shadow 0.15s;
}
.tool-card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: 0 6px 18px rgba(14, 122, 95, 0.12);
}
.tool-icon { font-size: 32px; margin-bottom: 10px; }
.tool-card h2 { margin: 0 0 6px; font-size: 18px; }
.tool-card p { margin: 0; color: var(--muted); font-size: 14px; }

/* Merge list */
.merge-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 12px 14px;
  border: 1px solid var(--border);
  border-radius: 8px;
  margin-bottom: 10px;
  background: var(--bg);
}
.merge-row-info { min-width: 0; }
.merge-row-controls { display: flex; gap: 6px; flex-shrink: 0; }
.row-btn {
  border: 1px solid var(--border);
  background: var(--panel);
  border-radius: 6px;
  padding: 5px 10px;
  font-size: 14px;
  cursor: pointer;
  color: var(--ink);
}
.row-btn:hover:not(:disabled) { border-color: var(--accent); color: var(--accent-dark); }
.row-btn:disabled { opacity: 0.35; cursor: default; }
.merge-actions { display: flex; gap: 10px; margin-top: 6px; flex-wrap: wrap; }

/* Language picker */
.lang-picker { display: flex; gap: 2px; border: 1px solid var(--border); border-radius: 999px; padding: 2px; }
.lang-picker button {
  border: none;
  background: transparent;
  font: inherit;
  font-size: 12px;
  font-weight: 700;
  color: var(--muted);
  padding: 3px 10px;
  border-radius: 999px;
  cursor: pointer;
}
.lang-picker button.active { background: var(--accent); color: #fff; }

/* Thumbnail page picker */
.thumb-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(132px, 1fr));
  gap: 12px;
  margin: 14px 0;
  max-height: 420px;
  overflow-y: auto;
  padding: 10px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--bg);
}
.thumb {
  position: relative;
  text-align: center;
  border-radius: 8px;
  padding: 8px 8px 26px;
  border: 2px solid transparent;
  transition: border-color 0.12s, background 0.12s, transform 0.12s;
}
.thumb-selectable { cursor: pointer; }
.thumb-selectable:hover { transform: translateY(-2px); background: #fff; border-color: var(--border); }
.thumb-frame {
  display: inline-block;
  transition: transform 0.25s ease;
  line-height: 0;
}
.thumb canvas {
  background: #fff;
  box-shadow: 0 1px 4px rgba(28, 37, 48, 0.18);
  border-radius: 3px;
  min-height: 40px;
}
.thumb-num {
  position: absolute;
  bottom: 5px;
  left: 0;
  right: 0;
  font-size: 12px;
  font-weight: 600;
  color: var(--muted);
}
.thumb.selected { border-color: var(--accent); background: var(--accent-soft); }
.thumb.selected .thumb-num { color: var(--accent-dark); }
.thumb.selected::after {
  content: '✓';
  position: absolute;
  top: 4px;
  right: 4px;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--accent);
  color: #fff;
  font-size: 13px;
  font-weight: 700;
  line-height: 22px;
  text-align: center;
}
.thumb-remove.selected { border-color: var(--error); background: #fdeceb; }
.thumb-remove.selected .thumb-num { color: var(--error); }
.thumb-remove.selected::after { content: '✕'; background: var(--error); }
.thumb-remove.selected canvas { opacity: 0.45; }

/* Range grouping colors (range picker + fixed-size preview) */
.thumb-g0 { --grp: #0e7a5f; --grp-soft: #e3f3ee; }
.thumb-g1 { --grp: #2563ab; --grp-soft: #e5eef8; }
.thumb-g2 { --grp: #c2620a; --grp-soft: #fbeedd; }
.thumb-g3 { --grp: #7c3aad; --grp-soft: #f1e8f9; }
.thumb-g4 { --grp: #b52e5b; --grp-soft: #fae7ee; }
.thumb-g5 { --grp: #0d7d86; --grp-soft: #e2f4f5; }
.thumb-grp { border-color: var(--grp); background: var(--grp-soft); }
.thumb-grp .thumb-num { color: var(--grp); }
.thumb-grp-active { box-shadow: 0 0 0 3px var(--grp-soft), 0 0 0 4px var(--grp); }

.range-dot {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  flex-shrink: 0;
}
.dot-g0 { background: #0e7a5f; }
.dot-g1 { background: #2563ab; }
.dot-g2 { background: #c2620a; }
.dot-g3 { background: #7c3aad; }
.dot-g4 { background: #b52e5b; }
.dot-g5 { background: #0d7d86; }
.range-row.active .range-label { color: var(--ink); }
.range-row { border-left: 3px solid transparent; padding-left: 8px; margin-left: -11px; }
.range-row.active { border-left-color: var(--accent); }

.thumb-toolbar {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
  margin-top: 8px;
}
.thumb-toolbar .hint { margin: 0; }
.thumb-actions { display: flex; gap: 14px; }
.link-btn {
  background: none;
  border: none;
  padding: 0;
  font: inherit;
  font-size: 14px;
  font-weight: 600;
  color: var(--accent-dark);
  cursor: pointer;
  text-decoration: underline;
}

/* Merge cover thumbnails */
.merge-row-left { display: flex; align-items: center; gap: 12px; min-width: 0; }
.merge-cover {
  background: #fff;
  box-shadow: 0 1px 3px rgba(28, 37, 48, 0.2);
  border-radius: 2px;
  flex-shrink: 0;
}

/* Trust section */
.trust h2 { text-align: center; font-size: 22px; margin: 40px 0 18px; }
.trust-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(210px, 1fr)); gap: 16px; }
.trust-card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px 20px;
}
.trust-card h3 { margin: 0 0 8px; font-size: 16px; }
.trust-card p { margin: 0; color: var(--muted); font-size: 14px; }

.site-footer {
  text-align: center;
  color: var(--muted);
  font-size: 13px;
  padding: 24px;
  border-top: 1px solid var(--border);
}

@media (max-width: 560px) {
  .hero h1 { font-size: 28px; }
  .panel { padding: 18px; }
  .site-header { justify-content: center; }
  .privacy-pill { margin-left: 0; }
}