:root {
  --bg: #f6f7fb;
  --card: #ffffff;
  --text: #111827;
  --muted: #6b7280;
  --border: #e5e7eb;
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --danger: #dc2626;
  --soft: #eef2ff;
  --shadow: 0 18px 45px rgba(15, 23, 42, 0.08);
}

body.dark {
  --bg: #0b1220;
  --card: #111827;
  --text: #f9fafb;
  --muted: #9ca3af;
  --border: #263244;
  --primary: #60a5fa;
  --primary-dark: #3b82f6;
  --danger: #f87171;
  --soft: #172554;
  --shadow: 0 18px 45px rgba(0, 0, 0, 0.25);
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial, sans-serif;
  background: radial-gradient(circle at top left, var(--soft), var(--bg) 36%);
  color: var(--text);
}
.app {
  width: min(980px, 100%);
  margin: 0 auto;
  padding: 20px 14px 36px;
}
.hero {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  align-items: flex-start;
  padding: 10px 2px 16px;
}
.eyebrow { margin: 0 0 6px; color: var(--primary); font-weight: 700; letter-spacing: .08em; text-transform: uppercase; font-size: 12px; }
h1 { margin: 0; font-size: clamp(26px, 6vw, 44px); line-height: 1.05; }
.subtitle { margin: 10px 0 0; color: var(--muted); font-size: 15px; }
.card {
  background: color-mix(in srgb, var(--card) 94%, transparent);
  border: 1px solid var(--border);
  border-radius: 22px;
  padding: 16px;
  box-shadow: var(--shadow);
  margin: 14px 0;
}
h2 { margin: 0 0 12px; font-size: 18px; }
.section-title { display: flex; justify-content: space-between; align-items: center; gap: 12px; }
textarea {
  width: 100%; min-height: 185px; resize: vertical;
  border: 1px solid var(--border); border-radius: 16px;
  padding: 14px; font-size: 18px; line-height: 1.55;
  color: var(--text); background: transparent; outline: none;
}
textarea:focus, select:focus, input:focus { border-color: var(--primary); box-shadow: 0 0 0 3px color-mix(in srgb, var(--primary) 20%, transparent); }
body.dark textarea, body.dark select, body.dark input[type="number"] {
  background: #0f172a;
  color: #f9fafb;
}
body.dark input[type="color"] {
  background: #0f172a;
}
.mini-row { display: flex; justify-content: space-between; align-items: center; margin-top: 8px; color: var(--muted); }
.mode-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; }
.mode-option {
  border: 1px solid var(--border); border-radius: 16px; padding: 14px;
  cursor: pointer; display: grid; gap: 5px; color: var(--muted);
}
.mode-option input { display: none; }
.mode-option strong { color: var(--text); }
.mode-option.active { border-color: var(--primary); background: color-mix(in srgb, var(--primary) 10%, transparent); }
.form-grid { display: grid; grid-template-columns: 1.4fr 1fr 0.8fr 1fr 0.8fr 0.8fr 1fr; gap: 12px; }
label { display: grid; gap: 7px; color: var(--muted); font-size: 14px; }
select, input[type="number"], input[type="color"] {
  width: 100%; border: 1px solid var(--border); border-radius: 14px;
  padding: 12px; font-size: 16px; color: var(--text); background: transparent;
}
input[type="range"] { width: 100%; accent-color: var(--primary); }
.toggles { display: flex; flex-wrap: wrap; gap: 12px 18px; margin-top: 14px; }
.toggles label { display: flex; flex-direction: row; align-items: center; }
.button-row { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 10px; }
button { border: 0; border-radius: 15px; padding: 13px 15px; font-weight: 700; font-size: 16px; cursor: pointer; }
button:disabled { opacity: .45; cursor: not-allowed; }
.primary-btn { background: var(--primary); color: white; }
.primary-btn:hover { background: var(--primary-dark); }
.secondary-btn { background: color-mix(in srgb, var(--primary) 12%, var(--card)); color: var(--text); border: 1px solid var(--border); }
.danger-btn { background: color-mix(in srgb, var(--danger) 14%, var(--card)); color: var(--danger); border: 1px solid color-mix(in srgb, var(--danger) 30%, var(--border)); }
.ghost-btn, .icon-btn, .link-btn { background: transparent; border: 1px solid var(--border); color: var(--text); }
.link-btn { padding: 8px 10px; font-size: 14px; color: var(--primary); border: 0; }
.icon-btn { width: 44px; height: 44px; padding: 0; border-radius: 50%; }
.progress-wrap { margin-top: 14px; }
.progress-head { display: flex; justify-content: space-between; color: var(--muted); margin-bottom: 8px; font-size: 14px; }
progress { width: 100%; height: 12px; accent-color: var(--primary); }
#modeBadge { font-size: 13px; color: var(--primary); font-weight: 700; }
input[type="color"] { height: 46px; padding: 6px; cursor: pointer; }
.preview {
  min-height: 160px;
  height: var(--preview-height, 280px);
  max-height: 78vh;
  overflow: auto;
  resize: none;
  border: 1px dashed var(--border); border-radius: 16px;
  padding: 15px; font-size: 20px; line-height: 1.75; white-space: pre-wrap;
  background: color-mix(in srgb, var(--card) 88%, var(--bg));
}
.output-card .layout-body::after {
  content: "↕ Kéo thanh Resize dưới Preview để chỉnh cao/thấp";
  display: block;
  margin-top: 8px;
  color: var(--muted);
  font-size: 12px;
  text-align: right;
}
.preview::-webkit-resizer {
  background: color-mix(in srgb, var(--primary) 26%, var(--card));
  border-radius: 8px;
}
body.dark .preview {
  background: #0f172a;
}
.preview.empty { color: var(--muted); }
.preview .chunk { padding: 2px 0; border-radius: 8px; color: var(--reader-normal, var(--text)); }
.preview .active { color: var(--reader-normal, var(--text)); }
.preview .segment { display: inline; border-radius: 8px; padding: 1px 2px; transition: color .22s ease, text-shadow .22s ease, opacity .22s ease, filter .22s ease, transform .22s ease; }
.preview .done-segment {
  color: color-mix(in srgb, var(--reader-karaoke, #22c55e) 55%, var(--reader-normal, var(--text)));
  font-weight: 620;
  opacity: .76;
}
.preview .active-segment {
  color: var(--reader-karaoke, #22c55e);
  font-weight: 850;
  opacity: 1;
  filter: brightness(1.12);
  transform: translateY(-1px);
  text-shadow: 0 0 7px color-mix(in srgb, var(--reader-karaoke, #22c55e) 32%, transparent);
}
footer { color: var(--muted); text-align: center; font-size: 13px; padding: 5px 12px; }
@media (max-width: 740px) {
  .mode-grid, .form-grid, .button-row { grid-template-columns: 1fr; }
  .card { border-radius: 18px; padding: 14px; }
  textarea { min-height: 220px; font-size: 17px; }
  .preview { font-size: 18px; height: var(--preview-height-mobile, var(--preview-height, 300px)); max-height: 72vh; }
}

.preview .next-segment {
  color: var(--reader-normal, var(--text));
  opacity: .95;
}
.preview .active-segment::selection,
.preview .done-segment::selection,
.preview .next-segment::selection {
  background: color-mix(in srgb, var(--reader-karaoke, #22c55e) 22%, transparent);
}

.library-grid {
  display: grid;
  grid-template-columns: 1fr 1.25fr;
  gap: 12px;
}
.library-actions {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
  margin-top: 12px;
}
.library-actions.secondary-line {
  grid-template-columns: 1.2fr 1fr 1fr;
}
input[type="text"] {
  width: 100%;
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 12px;
  font-size: 16px;
  color: var(--text);
  background: transparent;
}
body.dark input[type="text"] {
  background: #0f172a;
  color: #f9fafb;
}
.file-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  border-radius: 15px;
  padding: 13px 15px;
  font-weight: 700;
  font-size: 16px;
  cursor: pointer;
  color: var(--text);
  background: color-mix(in srgb, var(--primary) 12%, var(--card));
  border: 1px solid var(--border);
  text-align: center;
}
.file-btn input[type="file"] {
  display: none;
}
.library-help {
  margin: 10px 0 0;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.45;
}
#libraryCount {
  font-size: 13px;
  color: var(--primary);
  font-weight: 700;
}
@media (max-width: 740px) {
  .library-grid,
  .library-actions,
  .library-actions.secondary-line {
    grid-template-columns: 1fr;
  }
}


/* v13 collapsible layouts */
.layout-title,
.card > .section-title {
  min-height: 36px;
}
.layout-body {
  overflow: hidden;
  animation: layoutOpen .16s ease-out;
}
@keyframes layoutOpen {
  from { opacity: 0; transform: translateY(-4px); }
  to { opacity: 1; transform: translateY(0); }
}
.collapse-btn {
  margin-left: auto;
  padding: 8px 12px;
  border-radius: 999px;
  font-size: 13px;
  line-height: 1;
  background: color-mix(in srgb, var(--primary) 10%, var(--card));
  color: var(--primary);
  border: 1px solid color-mix(in srgb, var(--primary) 24%, var(--border));
  white-space: nowrap;
}
.card.collapsed {
  padding-bottom: 12px;
}
.card.collapsed .section-title {
  margin-bottom: 0;
}
.card.collapsed .collapse-btn {
  background: var(--primary);
  color: white;
  border-color: var(--primary);
}
@media (max-width: 740px) {
  .section-title {
    align-items: flex-start;
  }
  .collapse-btn {
    padding: 9px 12px;
    min-width: 68px;
  }
}


/* v15 fixed Reading Preview resize handle */
.preview-resize-bar {
  margin-top: 10px;
  height: 34px;
  border-radius: 14px;
  border: 1px dashed color-mix(in srgb, var(--primary) 34%, var(--border));
  background: color-mix(in srgb, var(--primary) 9%, var(--card));
  color: var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-weight: 800;
  font-size: 13px;
  cursor: ns-resize;
  user-select: none;
  touch-action: none;
}
.preview-resize-bar::before {
  content: "↕";
  font-size: 18px;
  line-height: 1;
}
.preview-resize-bar.dragging {
  background: color-mix(in srgb, var(--primary) 18%, var(--card));
  box-shadow: 0 10px 24px rgba(37, 99, 235, .18);
}
.preview-size-actions {
  display: flex;
  gap: 8px;
  justify-content: flex-end;
  margin-top: 8px;
}
.preview-size-actions button {
  padding: 8px 10px;
  border-radius: 12px;
  font-size: 13px;
}
@media (max-width: 740px) {
  .preview-resize-bar { height: 42px; font-size: 14px; }
  .preview-size-actions { justify-content: stretch; }
  .preview-size-actions button { flex: 1; }
}