:root {
  --bg: #f6f7f9;
  --card: #fff;
  --sunk: #eef0f4;
  --ink: #16181d;
  --muted: #6b7280;
  --line: #d9dde3;
  --accent: #2563eb;
  --accent-ink: #fff;
  --err: #b42318;
  --radius: 12px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #14161a;
    --card: #1c1f25;
    --sunk: #23272e;
    --ink: #e9ecf1;
    --muted: #9aa3af;
    --line: #333842;
    --accent: #4b82f6;
  }
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  padding: 0 max(12px, env(safe-area-inset-left)) calc(24px + env(safe-area-inset-bottom));
  background: var(--bg);
  color: var(--ink);
  font: 16px/1.5 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  overflow-wrap: anywhere;
}

header, main, footer { max-width: 1040px; margin: 0 auto; }

header { padding: 22px 4px 6px; }
.topbar { display: flex; align-items: center; justify-content: space-between; gap: 14px; }
.lang { flex: none; }
.lang select { width: auto; min-height: 40px; padding: 7px 10px; }
h1 { margin: 0; font-size: 1.6rem; letter-spacing: -0.02em; }
h2 { margin: 0 0 14px; font-size: 1.05rem; }
.sub { margin: 6px 0 0; color: var(--muted); font-size: 0.95rem; }

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 18px;
  margin: 14px 0;
}

fieldset {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 14px 16px 16px;
  margin: 0 0 14px;
  min-width: 0;
}
.grid2 fieldset { margin: 0; }
legend { padding: 0 8px; color: var(--muted); font-size: 0.9rem; }
legend b { color: var(--ink); }

.grid2 { display: grid; gap: 14px; grid-template-columns: 1fr; margin-bottom: 14px; }

.row { display: flex; gap: 14px; align-items: center; flex-wrap: wrap; }
.row.tight { gap: 10px; flex-wrap: nowrap; align-items: center; }
.row.tight input[type="range"] { flex: 1 1 auto; width: auto; min-width: 0; }
.row.tight .mono { flex: none; min-width: 2.5ch; text-align: right; white-space: nowrap; }
.between { justify-content: space-between; }

/* Controls laid out as a responsive grid: each keeps its label above it, so
   nothing gets squeezed into an unreadable strip on narrow screens. */
.field-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(132px, 1fr));
  gap: 14px 18px;
  align-items: end;
}
/* A bare button has no caption above it, so give it its own full-width row
   rather than letting a two-line label out-grow the inputs beside it. */
.field-grid > button { grid-column: 1 / -1; justify-self: start; padding: 9px 18px; }

.field {
  display: flex;
  flex-direction: column;
  align-items: stretch;
  gap: 5px;
  min-width: 0;
  font-size: 0.82rem;
  color: var(--muted);
}
.field > input, .field > select, .field > button { width: 100%; }
/* Match the 44px height of a plain control so captions line up across the row */
.field > .row.tight { min-height: 44px; }
.field input[type="number"], .field input[type="text"] { width: 100%; }
.field input[type="color"] { width: 92px; height: 44px; }
.field .lbl { display: block; }

label { font-size: 0.92rem; color: var(--muted); min-width: 0; max-width: 100%; }
label.check { display: inline-flex; align-items: center; gap: 9px; color: var(--ink); font-size: 0.95rem; }
label.check.spaced { margin-top: 14px; }

input, select, button {
  font: inherit;
  font-size: 16px;
  color: var(--ink);
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 9px 10px;
  min-height: 44px;
}
select { max-width: 100%; min-width: 0; }
input[type="checkbox"] { min-height: 0; width: 20px; height: 20px; flex: none; accent-color: var(--accent); }
input[type="color"] { padding: 4px; }
input[type="range"] { min-height: 0; padding: 0; width: 100%; border: 0; accent-color: var(--accent); }
input:disabled { opacity: 0.45; }
input:focus-visible, select:focus-visible, button:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

button { cursor: pointer; -webkit-tap-highlight-color: transparent; }
button:disabled { opacity: 0.5; cursor: not-allowed; }
.primary { background: var(--accent); color: var(--accent-ink); border-color: transparent; font-weight: 600; }
.ghost { background: transparent; color: var(--muted); font-size: 0.85rem; }
.big { padding: 12px 22px; min-height: 50px; font-size: 1rem; }

.drop {
  border: 2px dashed var(--line);
  border-radius: var(--radius);
  padding: 24px 12px;
  text-align: center;
  transition: border-color .15s, background .15s;
}
.drop.over { border-color: var(--accent); background: color-mix(in srgb, var(--accent) 8%, transparent); }
.drop p { margin: 6px 0; }

#listBar {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 18px;
  align-items: end;
  justify-content: space-between;
  margin-top: 16px;
}
#listBar .row { align-items: end; }
/* sits beside a 44px select, so it needs the same box to read as aligned */
#listBar label.check { min-height: 44px; }
#count { font-size: 0.95rem; padding-bottom: 10px; }

.hint { color: var(--muted); font-size: 0.85rem; margin: 10px 0 0; line-height: 1.45; }
.mono { font-family: ui-monospace, SFMono-Regular, Menlo, monospace; font-size: 0.85rem; color: var(--muted); }
.err { color: var(--err); font-size: 0.85rem; white-space: pre-wrap; }

.thumbs {
  list-style: none;
  margin: 14px 0 0;
  padding: 0;
  display: grid;
  gap: 10px;
  grid-template-columns: repeat(auto-fill, minmax(96px, 1fr));
}
.thumbs li {
  position: relative;
  /* mirrors the real collage cell shape, set from the detected cell size */
  aspect-ratio: var(--tile-aspect, 3 / 4);
  border-radius: 9px;
  overflow: hidden;
  background: var(--sunk);
  border: 1px solid var(--line);
}
/* contain, not cover: the tile should show the real shape of the photo */
.thumbs img { width: 100%; height: 100%; object-fit: contain; display: block; }
.thumbs .idx {
  position: absolute; top: 4px; left: 4px;
  background: #000b; color: #fff;
  font: 600 11px/1 ui-monospace, monospace;
  padding: 4px 6px; border-radius: 5px;
}
.thumbs .tools { position: absolute; inset: auto 0 0 0; display: flex; opacity: 0.9; }
.thumbs .tools button {
  flex: 1; min-height: 32px; padding: 0;
  border: 0; border-radius: 0;
  background: #000b; color: #fff;
  font-size: 15px; line-height: 32px;
}
.thumbs .tools button:hover { background: var(--accent); }
.thumbs .tools button:disabled { opacity: 0.35; background: #000b; }
.thumbs li.dragging { opacity: 0.4; }
.thumbs li.dropTarget { outline: 2px solid var(--accent); outline-offset: -2px; }

.actions { display: flex; gap: 14px; align-items: center; flex-wrap: wrap; margin-top: 4px; }
.bar { height: 6px; background: var(--line); border-radius: 99px; overflow: hidden; margin-top: 14px; }
.bar > div { height: 100%; width: 0; background: var(--accent); transition: width .15s; }

.results { list-style: none; margin: 14px 0 0; padding: 0; display: grid; gap: 12px; grid-template-columns: 1fr; }
.results li { display: flex; gap: 14px; align-items: center; border: 1px solid var(--line); border-radius: var(--radius); padding: 10px; }
.results img { width: 88px; height: 88px; object-fit: contain; background: var(--sunk); border-radius: 6px; flex: none; }
.results .meta { min-width: 0; flex: 1; }
.results .meta b { display: block; font-size: 0.95rem; }
.results a.dl {
  display: inline-flex; align-items: center; min-height: 44px; padding: 0 16px;
  border-radius: 8px; background: var(--accent); color: var(--accent-ink);
  text-decoration: none; font-weight: 600; font-size: 0.9rem; flex: none;
}

footer { padding: 4px 4px 20px; color: var(--muted); font-size: 0.85rem; }
footer p { margin: 4px 0; }

@media (min-width: 720px) {
  body { padding-left: 20px; padding-right: 20px; }
  h1 { font-size: 2rem; }
  .card { padding: 22px; }
  .grid2 { grid-template-columns: 1fr 1fr; }
  .thumbs { grid-template-columns: repeat(auto-fill, minmax(120px, 1fr)); }
  .results { grid-template-columns: 1fr 1fr; }
}

/* Keep the main action reachable with one thumb on phones */
@media (max-width: 719px) {
  #generate { flex: 1; }
  .actions {
    position: sticky;
    bottom: calc(env(safe-area-inset-bottom) + 8px);
    background: var(--card);
    padding: 10px 0 8px;
    box-shadow: 0 -10px 14px -10px #0004, 0 -1px 0 var(--line);
    z-index: 5;
  }
}