/* ==========================================================================
   FLARE-Lab / merge_pdf — stylesheet
   Light + dark themes. `data-theme="light|dark"` on <html> overrides the
   OS preference; `auto` follows prefers-color-scheme.
   ========================================================================== */

:root {
  --flame-1: #ff6a2b;
  --flame-2: #f3372b;
  --flame-ink: #ffffff;

  --bg: #f6f7f9;
  --bg-elev: #ffffff;
  --bg-sunk: #eef0f4;
  --ink: #15181d;
  --ink-2: #4c5563;
  --ink-3: #808b9b;
  --line: #e0e4ea;
  --line-strong: #cbd2dc;
  --accent: #f3372b;
  --accent-soft: rgba(243, 55, 43, 0.09);
  --danger: #d92d20;
  --ok: #12855b;
  --shadow-sm: 0 1px 2px rgba(16, 24, 40, .06), 0 1px 3px rgba(16, 24, 40, .07);
  --shadow-md: 0 4px 6px -2px rgba(16, 24, 40, .05), 0 12px 16px -4px rgba(16, 24, 40, .10);
  --shadow-lg: 0 8px 8px -4px rgba(16, 24, 40, .04), 0 20px 24px -4px rgba(16, 24, 40, .12);
  --r-sm: 8px;
  --r-md: 12px;
  --r-lg: 16px;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0e1116;
    --bg-elev: #171b22;
    --bg-sunk: #11151b;
    --ink: #eef1f6;
    --ink-2: #aab3c0;
    --ink-3: #7b8593;
    --line: #262c36;
    --line-strong: #38404d;
    --accent: #ff6a4d;
    --accent-soft: rgba(255, 106, 77, 0.14);
    --danger: #f97066;
    --ok: #47c496;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, .5);
    --shadow-md: 0 8px 20px rgba(0, 0, 0, .45);
    --shadow-lg: 0 18px 40px rgba(0, 0, 0, .55);
    color-scheme: dark;
  }
}

:root[data-theme="dark"] {
  --bg: #0e1116;
  --bg-elev: #171b22;
  --bg-sunk: #11151b;
  --ink: #eef1f6;
  --ink-2: #aab3c0;
  --ink-3: #7b8593;
  --line: #262c36;
  --line-strong: #38404d;
  --accent: #ff6a4d;
  --accent-soft: rgba(255, 106, 77, 0.14);
  --danger: #f97066;
  --ok: #47c496;
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, .5);
  --shadow-md: 0 8px 20px rgba(0, 0, 0, .45);
  --shadow-lg: 0 18px 40px rgba(0, 0, 0, .55);
  color-scheme: dark;
}

* { box-sizing: border-box; }

html, body { height: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 15px/1.55 -apple-system, BlinkMacSystemFont, "Segoe UI", Inter, Roboto, "Helvetica Neue", Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
}

code, kbd { font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace; }

h1, h2, h3 { margin: 0; line-height: 1.2; letter-spacing: -0.02em; }

/* ── Top bar ─────────────────────────────────────────────────────────── */
.topbar {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 12px clamp(14px, 4vw, 40px);
  background: color-mix(in srgb, var(--bg-elev) 88%, transparent);
  backdrop-filter: saturate(150%) blur(10px);
  border-bottom: 1px solid var(--line);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--ink);
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 32px;
  height: 32px;
  border-radius: 9px;
  color: var(--flame-ink);
  background: linear-gradient(150deg, var(--flame-1), var(--flame-2));
  box-shadow: var(--shadow-sm);
}

.brand-text { display: flex; align-items: baseline; gap: 6px; font-size: 15px; }
.brand-text strong { letter-spacing: -0.015em; }
.brand-slash { color: var(--ink-3); }
.brand-text code { font-size: 13.5px; color: var(--ink-2); }

.topbar-actions { display: flex; align-items: center; gap: 10px; }

.badge-private {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 4px 9px;
  font-size: 12px;
  font-weight: 600;
  color: var(--ok);
  background: color-mix(in srgb, var(--ok) 12%, transparent);
  border: 1px solid color-mix(in srgb, var(--ok) 28%, transparent);
  border-radius: 999px;
  white-space: nowrap;
}

.icon-btn {
  display: grid;
  place-items: center;
  width: 34px;
  height: 34px;
  color: var(--ink-2);
  background: transparent;
  border: 1px solid var(--line);
  border-radius: 9px;
  cursor: pointer;
}
.icon-btn:hover { color: var(--ink); border-color: var(--line-strong); background: var(--bg-sunk); }
.ico-moon { display: none; }
:root[data-theme="dark"] .ico-sun { display: none; }
:root[data-theme="dark"] .ico-moon { display: block; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .ico-sun { display: none; }
  :root:not([data-theme="light"]) .ico-moon { display: block; }
  :root[data-theme="dark"] .ico-sun { display: none; }
}

/* ── Layout ──────────────────────────────────────────────────────────── */
main {
  flex: 1;
  width: 100%;
  max-width: 1180px;
  margin: 0 auto;
  padding: clamp(24px, 5vw, 56px) clamp(14px, 4vw, 32px) 64px;
}

.stage[hidden] { display: none; }

/* ── Hero + dropzone ─────────────────────────────────────────────────── */
.hero { text-align: center; margin-bottom: 30px; }
.hero h1 { font-size: clamp(30px, 5.5vw, 46px); font-weight: 700; }
.hero-sub { margin: 12px auto 0; max-width: 46ch; color: var(--ink-2); font-size: clamp(15px, 2vw, 17px); }

.dropzone {
  position: relative;
  display: grid;
  place-items: center;
  min-height: clamp(230px, 34vh, 320px);
  padding: 28px;
  background: var(--bg-elev);
  border: 2px dashed var(--line-strong);
  border-radius: var(--r-lg);
  cursor: pointer;
  transition: border-color .15s, background .15s, transform .15s;
}
.dropzone:hover { border-color: var(--accent); }
.dropzone:focus-visible { outline: 3px solid var(--accent-soft); outline-offset: 3px; border-color: var(--accent); }
.dropzone.is-over {
  border-color: var(--accent);
  background: var(--accent-soft);
  transform: scale(1.006);
}
.dz-inner { display: grid; justify-items: center; gap: 14px; text-align: center; pointer-events: none; }
.dz-inner .btn { pointer-events: auto; }
.dz-icon { color: var(--accent); }
.dz-hint { margin: 0; color: var(--ink-3); font-size: 14px; }

.feature-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(215px, 1fr));
  gap: 14px;
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
}
.feature-row li {
  padding: 14px 16px;
  font-size: 13.5px;
  color: var(--ink-2);
  background: var(--bg-elev);
  border: 1px solid var(--line);
  border-radius: var(--r-md);
}
.feature-row b { color: var(--ink); font-weight: 600; }

/* ── Buttons ─────────────────────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 9px 15px;
  font: inherit;
  font-size: 14px;
  font-weight: 600;
  color: var(--ink);
  background: var(--bg-elev);
  border: 1px solid var(--line-strong);
  border-radius: 10px;
  cursor: pointer;
  text-decoration: none;
  white-space: nowrap;
  transition: filter .15s, background .15s, border-color .15s, transform .06s;
}
.btn:hover { background: var(--bg-sunk); }
.btn:active { transform: translateY(1px); }
.btn:focus-visible { outline: 3px solid var(--accent-soft); outline-offset: 2px; }
.btn:disabled { opacity: .5; cursor: not-allowed; }

.btn-primary {
  color: var(--flame-ink);
  background: linear-gradient(150deg, var(--flame-1), var(--flame-2));
  border-color: transparent;
  box-shadow: var(--shadow-sm);
}
.btn-primary:hover { filter: brightness(1.06); background: linear-gradient(150deg, var(--flame-1), var(--flame-2)); }
.btn-lg { padding: 12px 24px; font-size: 15.5px; border-radius: 11px; }
.btn-block { width: 100%; }
.btn-ghost { background: transparent; border-color: var(--line); color: var(--ink-2); }
.btn-ghost:hover { color: var(--ink); background: var(--bg-sunk); border-color: var(--line-strong); }
.btn-ghost.danger:hover { color: var(--danger); border-color: color-mix(in srgb, var(--danger) 40%, transparent); }

/* ── Work stage ──────────────────────────────────────────────────────── */
.work-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 312px;
  gap: 26px;
  align-items: start;
}

.toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 6px;
}
.toolbar-left { display: flex; align-items: baseline; gap: 10px; }
.toolbar-title { font-size: 20px; font-weight: 700; display: inline-flex; align-items: center; gap: 8px; }
.count-chip {
  padding: 1px 8px;
  font-size: 12.5px;
  font-weight: 700;
  color: var(--accent);
  background: var(--accent-soft);
  border-radius: 999px;
}
.toolbar-right { display: flex; flex-wrap: wrap; gap: 8px; }
.muted-sm { font-size: 13px; color: var(--ink-3); }
.drag-hint { margin: 0 0 16px; font-size: 12.5px; color: var(--ink-3); }
.drag-hint kbd {
  padding: 1px 5px;
  font-size: 11px;
  border: 1px solid var(--line-strong);
  border-bottom-width: 2px;
  border-radius: 5px;
  background: var(--bg-elev);
}

/* ── File cards ──────────────────────────────────────────────────────── */
.file-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(188px, 1fr));
  gap: 16px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.card {
  position: relative;
  display: flex;
  flex-direction: column;
  background: var(--bg-elev);
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  box-shadow: var(--shadow-sm);
  transition: box-shadow .15s, border-color .15s, opacity .15s;
}
.card:hover { box-shadow: var(--shadow-md); border-color: var(--line-strong); }
.card.dragging { opacity: .35; }
.card.drop-target { border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-soft); }
.card.is-error { border-color: color-mix(in srgb, var(--danger) 45%, transparent); }

.card-index {
  position: absolute;
  top: 8px;
  left: 8px;
  z-index: 2;
  min-width: 22px;
  height: 22px;
  padding: 0 6px;
  display: grid;
  place-items: center;
  font-size: 11.5px;
  font-weight: 700;
  color: var(--flame-ink);
  background: linear-gradient(150deg, var(--flame-1), var(--flame-2));
  border-radius: 999px;
}

.card-remove {
  position: absolute;
  top: 6px;
  right: 6px;
  z-index: 2;
  width: 24px;
  height: 24px;
  display: grid;
  place-items: center;
  color: var(--ink-2);
  background: var(--bg-elev);
  border: 1px solid var(--line);
  border-radius: 7px;
  cursor: pointer;
  opacity: 0;
  transition: opacity .12s;
}
.card:hover .card-remove,
.card-remove:focus-visible { opacity: 1; }
.card-remove:hover { color: var(--danger); border-color: color-mix(in srgb, var(--danger) 45%, transparent); }

.thumb {
  position: relative;
  aspect-ratio: 3 / 4;
  display: grid;
  place-items: center;
  overflow: hidden;
  background: var(--bg-sunk);
  border-radius: calc(var(--r-md) - 1px) calc(var(--r-md) - 1px) 0 0;
  border-bottom: 1px solid var(--line);
  cursor: grab;
}
.thumb:active { cursor: grabbing; }
.thumb canvas, .thumb img {
  max-width: 100%;
  max-height: 100%;
  display: block;
  box-shadow: 0 1px 6px rgba(0, 0, 0, .18);
}
.thumb-fallback { color: var(--ink-3); display: grid; justify-items: center; gap: 6px; font-size: 11px; }
.thumb-skeleton {
  position: absolute;
  inset: 0;
  background: linear-gradient(100deg, transparent 20%, color-mix(in srgb, var(--ink-3) 12%, transparent) 50%, transparent 80%);
  background-size: 220% 100%;
  animation: sweep 1.1s linear infinite;
}
@keyframes sweep { from { background-position: 120% 0; } to { background-position: -120% 0; } }

/* `minmax(0, 1fr)` + `min-width: 0` keep long file names and the control row
   from widening the column past the card (a -webkit-box has a very large
   min-content width). */
.card-body {
  padding: 9px 10px 10px;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 8px;
}
.card-body > * { min-width: 0; }
.card-name {
  font-size: 12.5px;
  font-weight: 600;
  line-height: 1.35;
  overflow-wrap: anywhere;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.card-meta { font-size: 11.5px; color: var(--ink-3); display: flex; flex-wrap: wrap; gap: 5px; }
.card-meta .err { color: var(--danger); font-weight: 600; }

/* Wraps the page-range box onto its own line in narrow cards instead of
   squeezing it down to a truncated placeholder. */
.card-ctl { display: flex; align-items: center; gap: 5px; flex-wrap: wrap; }
.mini {
  display: grid;
  place-items: center;
  width: 26px;
  height: 26px;
  flex: none;
  font-size: 11px;
  font-weight: 700;
  color: var(--ink-2);
  background: transparent;
  border: 1px solid var(--line);
  border-radius: 7px;
  cursor: pointer;
}
.mini:hover:not(:disabled) { color: var(--ink); background: var(--bg-sunk); border-color: var(--line-strong); }
.mini:disabled { opacity: .35; cursor: not-allowed; }
.mini.on { color: var(--accent); border-color: color-mix(in srgb, var(--accent) 45%, transparent); background: var(--accent-soft); }

.range-input {
  flex: 1 1 66px;
  min-width: 0;
  padding: 4px 7px;
  font: inherit;
  font-size: 11.5px;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  color: var(--ink);
  background: var(--bg-sunk);
  border: 1px solid var(--line);
  border-radius: 7px;
}
.range-input::placeholder { color: var(--ink-3); }
.range-input:focus { outline: 2px solid var(--accent-soft); border-color: var(--accent); }
.range-input.bad { border-color: var(--danger); color: var(--danger); }

/* ── Side panel ──────────────────────────────────────────────────────── */
.work-side { position: sticky; top: 74px; }
.panel {
  display: grid;
  gap: 16px;
  padding: 18px;
  background: var(--bg-elev);
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  box-shadow: var(--shadow-sm);
}
.panel-title { font-size: 15px; font-weight: 700; }

.field { display: grid; gap: 6px; }
.field-label { font-size: 12.5px; font-weight: 600; color: var(--ink-2); }
.field-input-wrap {
  display: flex;
  align-items: center;
  background: var(--bg-sunk);
  border: 1px solid var(--line);
  border-radius: 9px;
  padding-right: 10px;
}
.field-input-wrap:focus-within { border-color: var(--accent); outline: 2px solid var(--accent-soft); }
.field-input {
  flex: 1;
  min-width: 0;
  padding: 9px 10px;
  font: inherit;
  font-size: 14px;
  color: var(--ink);
  background: transparent;
  border: 0;
  outline: none;
}
.field-suffix { font-size: 13px; color: var(--ink-3); }

.check { display: flex; gap: 10px; align-items: start; cursor: pointer; }
.check input { margin: 2px 0 0; width: 15px; height: 15px; accent-color: var(--accent); flex: none; }
.check b { display: block; font-size: 13px; font-weight: 600; }
.check em { display: block; margin-top: 2px; font-size: 11.5px; font-style: normal; color: var(--ink-3); line-height: 1.45; }

.summary {
  display: grid;
  gap: 4px;
  padding: 11px 12px;
  font-size: 12.5px;
  color: var(--ink-2);
  background: var(--bg-sunk);
  border: 1px solid var(--line);
  border-radius: 9px;
}
.summary .row { display: flex; justify-content: space-between; gap: 10px; }
.summary .row b { color: var(--ink); font-weight: 600; }
.panel-foot { margin: -4px 0 0; font-size: 11.5px; color: var(--ink-3); text-align: center; }

/* ── Done stage ──────────────────────────────────────────────────────── */
.done-card {
  max-width: 520px;
  margin: clamp(10px, 4vh, 40px) auto;
  padding: 34px 28px;
  display: grid;
  justify-items: center;
  gap: 14px;
  text-align: center;
  background: var(--bg-elev);
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  box-shadow: var(--shadow-lg);
}
.done-icon {
  display: grid;
  place-items: center;
  width: 62px;
  height: 62px;
  color: var(--ok);
  background: color-mix(in srgb, var(--ok) 13%, transparent);
  border-radius: 50%;
}
.done-card h2 { font-size: 24px; }
.done-meta { margin: 0; font-size: 13.5px; color: var(--ink-2); }
.done-links { display: flex; gap: 8px; margin-top: 6px; }

/* ── Overlay / spinner ───────────────────────────────────────────────── */
.overlay {
  position: fixed;
  inset: 0;
  z-index: 60;
  display: grid;
  place-items: center;
  background: color-mix(in srgb, var(--bg) 78%, transparent);
  backdrop-filter: blur(4px);
}
.overlay[hidden] { display: none; }
.overlay-box {
  display: grid;
  justify-items: center;
  gap: 14px;
  width: min(320px, 84vw);
  padding: 26px;
  background: var(--bg-elev);
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  box-shadow: var(--shadow-lg);
  text-align: center;
}
.overlay-box p { margin: 0; font-size: 14px; font-weight: 600; }
.spinner {
  width: 34px;
  height: 34px;
  border: 3px solid var(--line);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin .8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }
.bar { width: 100%; height: 6px; background: var(--bg-sunk); border-radius: 999px; overflow: hidden; }
.bar-fill {
  height: 100%;
  width: 0;
  background: linear-gradient(90deg, var(--flame-1), var(--flame-2));
  border-radius: 999px;
  transition: width .2s;
}

/* ── Toasts ──────────────────────────────────────────────────────────── */
.toasts {
  position: fixed;
  right: 16px;
  bottom: 16px;
  z-index: 80;
  display: grid;
  gap: 8px;
  max-width: min(360px, calc(100vw - 32px));
}
.toast {
  padding: 10px 13px;
  font-size: 13px;
  color: var(--ink);
  background: var(--bg-elev);
  border: 1px solid var(--line-strong);
  border-left: 3px solid var(--accent);
  border-radius: 10px;
  box-shadow: var(--shadow-md);
  animation: rise .18s ease-out;
}
.toast.err { border-left-color: var(--danger); }
.toast.ok { border-left-color: var(--ok); }
@keyframes rise { from { opacity: 0; transform: translateY(8px); } }

/* ── Footer ──────────────────────────────────────────────────────────── */
.sitefoot {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 8px;
  padding: 20px 16px 26px;
  font-size: 12.5px;
  color: var(--ink-3);
  border-top: 1px solid var(--line);
}
.sitefoot .dot { opacity: .5; }

/* ── Responsive ──────────────────────────────────────────────────────── */
@media (max-width: 900px) {
  .work-layout { grid-template-columns: minmax(0, 1fr); }
  .work-side { position: static; order: -1; }
}
@media (max-width: 520px) {
  .file-grid { grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); gap: 12px; }
  .badge-private { display: none; }
  .toolbar-right { width: 100%; }
  .toolbar-right .btn { flex: 1; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: .01ms !important; transition-duration: .01ms !important; }
}
