:root {
  color-scheme: light dark;
  --bg: #ffffff;
  --fg: #18181b;
  --muted: #71717a;
  --border: #e4e4e7;
  --border-strong: #d4d4d8;
  --border-stronger: #a1a1aa;
  --hover: #f4f4f5;
  --err: #dc2626;
}

/* Dark palette: same monochrome scale, inverted. An explicit choice
   (data-theme) always wins over the OS-level media query below — see the
   :root[data-theme="dark"] block, which applies regardless of OS setting. */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --bg: #09090b;
    --fg: #f4f4f5;
    --muted: #a1a1aa;
    --border: #3f3f46;
    --border-strong: #52525b;
    --border-stronger: #71717a;
    --hover: #27272a;
    --err: #f87171;
  }
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --bg: #09090b;
  --fg: #f4f4f5;
  --muted: #a1a1aa;
  --border: #3f3f46;
  --border-strong: #52525b;
  --border-stronger: #71717a;
  --hover: #27272a;
  --err: #f87171;
}

:root[data-theme="light"] {
  color-scheme: light;
}

*, *::before, *::after { box-sizing: border-box; }

html, body { margin: 0; }

body {
  color: var(--fg);
  background: var(--bg);
  line-height: 1.6;
  font-size: 16px;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Apple SD Gothic Neo", "Noto Sans KR", sans-serif;
  -webkit-font-smoothing: antialiased;
  word-break: keep-all;
  overflow-wrap: break-word;
}

a { color: inherit; }

/* header */
header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  max-width: 960px;
  margin: 0 auto;
  padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--border);
}

.wordmark {
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--fg);
  text-decoration: none;
}

.langtoggle {
  display: flex;
  align-items: center;
  gap: .3rem;
}
.langsel {
  font: inherit;
  font-size: .85rem;
  color: var(--muted);
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: .15rem .4rem;
  cursor: pointer;
}

.themetoggle {
  font: inherit;
  font-size: .85rem;
  line-height: 1;
  color: var(--muted);
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: .2rem .45rem;
  cursor: pointer;
}
.themetoggle:hover {
  background: var(--hover);
  border-color: var(--border-strong);
}

/* main */
main {
  max-width: 720px;
  margin: 0 auto;
  padding: 2.5rem 1.25rem 4rem;
}
main.wide { max-width: 960px; }

/* hero (landing) */
.hero h1 {
  font-size: clamp(1.75rem, 4vw, 2.25rem);
  font-weight: 600;
  letter-spacing: -0.02em;
  margin: 0 0 .5rem;
}
.hero p {
  color: var(--muted);
  font-size: 1.05rem;
  margin: 0;
}

/* landing groups */
.groups { max-width: 960px; margin: 0 auto; }
.group { margin-top: 2.5rem; }
.group h2 {
  font-size: .8rem;
  text-transform: uppercase;
  letter-spacing: .08em;
  color: var(--muted);
  font-weight: 600;
  margin: 0 0 .75rem;
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(210px, 1fr));
  gap: .75rem;
}

.card-link {
  display: flex;
  flex-direction: column;
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: .9rem 1rem;
  text-decoration: none;
  color: var(--fg);
  transition: background .12s, border-color .12s;
}
.card-link:hover {
  background: var(--hover);
  border-color: var(--border-strong);
}
.card-link .name {
  font-weight: 550;
  display: block;
}
.card-link .desc {
  color: var(--muted);
  font-size: .875rem;
  display: block;
  margin-top: .15rem;
}

/* tool page */
main h1 {
  font-size: 1.5rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  margin: 0 0 .35rem;
}
main .desc {
  color: var(--muted);
  margin: 0 0 1.5rem;
}

/* dropzone */
.drop {
  border: 1.5px dashed var(--border);
  border-radius: 12px;
  padding: 2.25rem 1.25rem;
  text-align: center;
  color: var(--muted);
  cursor: pointer;
  transition: .12s;
}
.drop:hover,
.drop.over {
  border-color: var(--border-stronger);
  background: var(--hover);
}
.drop:focus-visible {
  outline: 2px solid var(--fg);
  outline-offset: 2px;
}
.drop .filelist {
  list-style: none;
  padding: 0;
  margin: .75rem 0 0;
  font-size: .85rem;
  color: var(--fg);
}
.drop .filelist li { margin-top: .15rem; }
.drop input[type="file"] {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

/* signature pad */
.signpad { display: inline-block; max-width: 100%; }
.signcanvas {
  display: block;
  width: 400px;
  max-width: 100%;
  height: 160px;
  background: #ffffff;
  border: 1.5px dashed var(--border);
  border-radius: 12px;
  touch-action: none;
  cursor: crosshair;
}
.signcanvas:hover { border-color: var(--border-stronger); }
#drawFields button.secondary { margin-top: .75rem; }

/* controls */
label {
  display: block;
  font-weight: 600;
  font-size: .88rem;
  margin: 1rem 0 .35rem;
}
label:first-of-type { margin-top: 0; }

input[type="text"],
input[type="number"],
select,
textarea {
  font: inherit;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: .5rem .6rem;
  background: var(--bg);
  color: var(--fg);
  width: auto;
}
textarea { width: 100%; resize: vertical; }

input[type="text"]:focus-visible,
input[type="number"]:focus-visible,
select:focus-visible,
textarea:focus-visible {
  outline: 2px solid var(--fg);
  outline-offset: 1px;
}

input[type="checkbox"],
input[type="radio"],
input[type="range"] {
  accent-color: var(--fg);
}

.checkline {
  display: flex;
  gap: .5rem;
  align-items: center;
  margin: 1rem 0;
}
.checkline label { margin: 0; font-weight: 400; }

.hint {
  color: var(--muted);
  font-size: .82rem;
  margin: .3rem 0 0;
}

/* buttons */
button.primary {
  margin-top: 1.5rem;
  background: var(--fg);
  color: var(--bg);
  border: none;
  border-radius: 8px;
  padding: .6rem 1.25rem;
  font: inherit;
  font-weight: 550;
  cursor: pointer;
}
button.primary:hover { opacity: .88; }
button.primary:disabled { opacity: .45; cursor: default; }

button.secondary {
  background: none;
  border: 1px solid var(--border);
  color: var(--fg);
  border-radius: 8px;
  padding: .4rem .8rem;
  font: inherit;
  font-size: .85rem;
  cursor: pointer;
}
button.secondary:hover { background: var(--hover); }
button.secondary:disabled { opacity: .45; cursor: default; }

:focus-visible {
  outline: 2px solid var(--fg);
  outline-offset: 2px;
}

/* status / errors / links */
#status { color: var(--muted); font-size: .9rem; }
.err { color: var(--err); margin-top: 1rem; min-height: 1.2em; }
.back { color: var(--muted); text-decoration: none; font-size: .9rem; }
.back:hover { color: var(--fg); }

.result {
  font-size: .85rem;
  color: var(--muted);
  margin-top: 1rem;
}

dl.info { margin: 0; }
dl.info dt { font-size: .78rem; color: var(--muted); margin-top: .75rem; }
dl.info dd { margin: .1rem 0 0; font-size: .98rem; }
.pagesizes {
  font-size: .8rem;
  color: var(--muted);
  white-space: pre-wrap;
  margin: .75rem 0 0;
}

/* footer */
footer {
  max-width: 720px;
  margin: 0 auto;
  padding: 2rem 1.25rem;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: .85rem;
  text-align: center;
}

@media (max-width: 480px) {
  main { padding: 1.75rem 1rem 3rem; }
}

@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; }
}

.page-info { margin-top: 3rem; border-top: 1px solid var(--border); padding-top: 1.5rem; }
.page-info h2 { font-size: 1.05rem; font-weight: 600; margin: 1.5rem 0 .5rem; }
.page-info ol { padding-left: 1.25rem; margin: 0; } .page-info li { margin: .35rem 0; }
.page-info h3 { font-size: .95rem; font-weight: 600; margin: 1rem 0 .25rem; }
.page-info p { margin: 0; color: var(--muted); }

/* page-thumbnail grid (progressive enhancement — Reorder/Remove/Split) */
.thumbgrid { margin: 1.25rem 0; }
.thumbgrid .thumbhint,
.thumbgrid .thumbnotice { margin: 0 0 .5rem; }
.thumbcells {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: .6rem;
}
.thumbcell {
  position: relative;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: .35rem;
  background: var(--bg);
  cursor: pointer;
  user-select: none;
  transition: border-color .12s, opacity .12s, box-shadow .12s;
}
.thumbcell:hover { border-color: var(--border-stronger); }
.thumbcell canvas { display: block; width: 100%; height: auto; border-radius: 4px; }
.thumbcell .thumbnum {
  display: block;
  text-align: center;
  font-size: .75rem;
  color: var(--muted);
  margin-top: .3rem;
}
.thumbcell[draggable="true"] { cursor: grab; }
.thumbcell.dragging { opacity: .4; }
.thumbcell.dragover-before { box-shadow: -3px 0 0 var(--fg); }
.thumbcell.dragover-after { box-shadow: 3px 0 0 var(--fg); }
.thumbcell.removed { opacity: .35; }
.thumbcell.removed::after {
  content: "\2715";
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.75rem;
  color: var(--err);
  pointer-events: none;
}
.thumbcell.selected { border-color: var(--fg); box-shadow: 0 0 0 2px var(--fg) inset; }

/* PWA "Open with which tool?" chooser (file-handler launch on the index page) */
.launch-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, .4);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1.25rem;
  z-index: 100;
}
.launch-box {
  background: var(--bg);
  color: var(--fg);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.5rem;
  max-width: 420px;
  width: 100%;
}
.launch-box h2 {
  font-size: 1.1rem;
  font-weight: 600;
  margin: 0 0 1rem;
}
.launch-list {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
  gap: .6rem;
}
.launch-cancel { margin-top: 1.25rem; }