:root {
  --bg: #f6f7f9;
  --surface: #ffffff;
  --text: #191a1f;
  --muted: #5f6470;
  --border: #dfe2e8;
  --accent: #1d4ed8;
  --accent-contrast: #ffffff;
  --danger: #b91c1c;
  --focus: #1d4ed8;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #131316;
    --surface: #1e1f24;
    --text: #ececf1;
    --muted: #a2a7b3;
    --border: #35373f;
    --accent: #60a5fa;
    --accent-contrast: #0b1c36;
    --danger: #f87171;
    --focus: #93c5fd;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.4);
  }
}

* { box-sizing: border-box; }

html { height: 100%; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
}

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

/* ---------- Header / nav ---------- */

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  padding: 0.65rem 1rem;
  border-bottom: 1px solid var(--border);
  background: var(--surface);
}

.brand {
  font-weight: 700;
  text-decoration: none;
  color: var(--text);
  font-size: 1.05rem;
  white-space: nowrap;
}

.site-nav { display: flex; gap: 0.25rem; }

.site-nav a {
  text-decoration: none;
  color: var(--muted);
  font-weight: 600;
  font-size: 0.95rem;
  padding: 0.45rem 0.75rem;
  border-radius: 8px;
}

.site-nav a:hover { color: var(--text); }
.site-nav a[aria-current="page"] { color: var(--accent); }

.container {
  width: 100%;
  max-width: 760px;
  margin: 0 auto;
  padding: 1.25rem 1rem 3rem;
  flex: 1;
}

/* ---------- Landing ---------- */

.hero { text-align: center; padding: 1.5rem 0 0.5rem; }
.hero h1 { margin: 0 0 0.5rem; font-size: clamp(1.5rem, 4vw, 2.25rem); }
.hero p { margin: 0; color: var(--muted); }

.tool-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1rem;
  margin-top: 1.5rem;
}

.tool-card {
  display: block;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.25rem;
  text-decoration: none;
  color: var(--text);
  box-shadow: var(--shadow);
}

.tool-card:hover { border-color: var(--accent); }
.tool-card .tool-icon { font-size: 2rem; }
.tool-card h2 { margin: 0.5rem 0 0.25rem; font-size: 1.15rem; }
.tool-card p { margin: 0 0 0.75rem; color: var(--muted); font-size: 0.92rem; }
.tool-card .tool-cta { color: var(--accent); font-weight: 600; font-size: 0.92rem; }

.site-footer {
  text-align: center;
  padding: 1rem;
  color: var(--muted);
  font-size: 0.85rem;
  border-top: 1px solid var(--border);
}

.site-footer p { margin: 0; }
.site-footer .footer-credit { margin-top: 0.25rem; }
.site-footer a { color: var(--accent); font-weight: 600; text-decoration: none; }
.site-footer a:hover { text-decoration: underline; }

/* ---------- Shared tool UI ---------- */

.page-title { margin: 0.5rem 0 0.25rem; font-size: 1.4rem; }
.page-sub { margin: 0 0 1.25rem; color: var(--muted); font-size: 0.95rem; }

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  font: inherit;
  font-weight: 600;
  font-size: 0.95rem;
  min-height: 2.75rem;
  padding: 0.5rem 1rem;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  cursor: pointer;
  text-decoration: none;
  -webkit-tap-highlight-color: transparent;
}

.btn:hover { filter: brightness(0.97); }
.btn:disabled { opacity: 0.5; cursor: not-allowed; }

.btn-primary {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--accent-contrast);
}

.btn-compact {
  min-height: 2.4rem;
  min-width: 2.4rem;
  padding: 0.3rem 0.55rem;
  font-size: 0.92rem;
  line-height: 1;
}

.btn.toggled {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--accent-contrast);
}

.dropzone {
  display: block;
  width: 100%;
  font: inherit;
  color: var(--text);
  border: 2px dashed var(--border);
  border-radius: 12px;
  background: var(--surface);
  padding: 2rem 1rem;
  text-align: center;
  cursor: pointer;
}

.dropzone.dragover { border-color: var(--accent); background: color-mix(in srgb, var(--accent) 6%, var(--surface)); }
.dropzone .dz-icon { font-size: 2rem; }
.dropzone p { margin: 0.5rem 0 0; color: var(--muted); font-size: 0.92rem; }
.dropzone strong { color: var(--text); }

.visually-hidden {
  position: absolute;
  width: 1px; height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

.status-line {
  color: var(--muted);
  font-size: 0.92rem;
  min-height: 1.4em;
  margin: 0.9rem 0 0;
}

.status-line.error { color: var(--danger); font-weight: 600; }

.spinner {
  display: inline-block;
  width: 0.9em;
  height: 0.9em;
  border: 2px solid currentColor;
  border-right-color: transparent;
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
  vertical-align: -0.1em;
  margin-right: 0.35em;
}

@keyframes spin { to { transform: rotate(360deg); } }

@media (prefers-reduced-motion: reduce) {
  .spinner { animation-duration: 1.5s; }
}

/* ---------- Merge tool ---------- */

.file-list { list-style: none; margin: 1rem 0 0; padding: 0; display: flex; flex-direction: column; gap: 0.5rem; }

.file-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 0.5rem 0.6rem;
  box-shadow: var(--shadow);
}

.file-item.dragging { opacity: 0.4; }
.file-item.drop-target { border-color: var(--accent); }

.drag-handle {
  cursor: grab;
  color: var(--muted);
  font-size: 1.05rem;
  padding: 0.5rem 0.4rem;
  border: none;
  background: none;
  touch-action: none;
  user-select: none;
  -webkit-user-select: none;
}

.file-info { flex: 1; min-width: 0; }
.file-name { font-weight: 600; font-size: 0.92rem; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.file-meta { color: var(--muted); font-size: 0.8rem; }
.file-actions { display: flex; gap: 0.3rem; }

.merge-actions { display: flex; flex-wrap: wrap; gap: 0.6rem; margin-top: 1.25rem; }

/* ---------- Editor ---------- */

.editor-main {
  max-width: none;
  padding: 0;
  display: flex;
  flex-direction: column;
}

.editor-intro { max-width: 640px; margin: 0 auto; padding: 1.25rem 1rem; width: 100%; }

.editor-toolbar {
  position: sticky;
  top: 0;
  z-index: 40;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.35rem;
  padding: 0.45rem 0.6rem;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
}

.editor-toolbar select,
.editor-toolbar input[type="number"] {
  font: inherit;
  font-size: 0.9rem;
  min-height: 2.4rem;
  padding: 0.3rem 0.35rem;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
}

.editor-toolbar input[type="number"] { width: 4.4rem; }

.editor-toolbar input[type="color"] {
  width: 2.4rem;
  height: 2.4rem;
  padding: 0.15rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--surface);
  cursor: pointer;
}

.tb-group { display: flex; align-items: center; gap: 0.3rem; }
.tb-sep { width: 1px; align-self: stretch; background: var(--border); margin: 0 0.2rem; }
.tb-spacer { flex: 1; }

.editor-stage {
  flex: 1;
  padding: 1rem 0.5rem 5rem;
}

.editor-stage.placing .page-overlay { cursor: crosshair; }

.editor-hint {
  color: var(--muted);
  font-size: 0.85rem;
  text-align: center;
  margin: 0 auto 0.75rem;
  max-width: 640px;
  padding: 0 0.5rem;
}

.pdf-page {
  position: relative;
  margin: 0 auto 1.25rem;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.25);
  background: #fff;
}

.pdf-page canvas { display: block; width: 100%; height: 100%; }

.page-label {
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  text-align: center;
  color: var(--muted);
  font-size: 0.75rem;
  padding-top: 0.15rem;
}

.page-overlay { position: absolute; inset: 0; }

.tbox {
  position: absolute;
  line-height: 1.2;
  white-space: pre;
  min-width: 0.5em;
  min-height: 1em;
  margin: 0;
  padding: 0;
  outline: none;
  cursor: grab;
  touch-action: none;
  border: 1px dashed transparent;
  user-select: none;
  -webkit-user-select: none;
}

.tbox.selected { border-color: #1d4ed8; }
.tbox.editing {
  cursor: text;
  touch-action: auto;
  user-select: text;
  -webkit-user-select: text;
  border-style: solid;
}

@media (max-width: 600px) {
  .editor-toolbar { padding: 0.35rem 0.4rem; }
  .btn { font-size: 0.9rem; }
}