:root {
  color-scheme: dark;
  --bg: #0b1220;
  --bg-elev: #131c2e;
  --bg-elev-2: #1b2640;
  --fg: #e6edf7;
  --fg-dim: #9aa7bd;
  --accent: #7dd3fc;
  --accent-warm: #fbbf24;
  --danger: #f87171;
  --border: #23304a;
  --radius: 10px;

  /* Semantic button colours so theme swaps never leave a hex literal behind (ADR-0012 B6). */
  --button-hover-bg: #243456;
  --button-hover-border: #324264;
  --button-primary-text: #06223a;
  --button-primary-hover-bg: #a3dcfd;
  --danger-border: #5b2a2a;

  font-family: system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
}

/* Light theme follows the OS preference. CSS-only, no JS, no persistence (ADR-0012 B1). */
@media (prefers-color-scheme: light) {
  :root {
    color-scheme: light;
    --bg: #f6f5f1;
    --bg-elev: #ffffff;
    --bg-elev-2: #ecebe6;
    --fg: #18222f;
    --fg-dim: #5a6677;
    --accent: #0e6dd1;
    --accent-warm: #b45309;
    --danger: #b91c1c;
    --border: #d6d3cb;

    --button-hover-bg: #e8e6df;
    --button-hover-border: #c3c0b6;
    --button-primary-text: #ffffff;
    --button-primary-hover-bg: #0c5fb8;
    --danger-border: #e2c2c2;
  }
}

* { box-sizing: border-box; }
html, body, #root { height: 100%; margin: 0; }
body {
  background: var(--bg);
  color: var(--fg);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--accent); }
a:hover { text-decoration: underline; }

button {
  font: inherit;
  color: var(--fg);
  background: var(--bg-elev-2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.55rem 0.95rem;
  cursor: pointer;
  transition: background 0.15s ease, border-color 0.15s ease;
}
button:hover:not(:disabled) { background: var(--button-hover-bg); border-color: var(--button-hover-border); }
button:disabled { opacity: 0.45; cursor: not-allowed; }
button.primary { background: var(--accent); color: var(--button-primary-text); border-color: transparent; font-weight: 600; }
button.primary:hover:not(:disabled) { background: var(--button-primary-hover-bg); }
button.danger { color: var(--danger); border-color: var(--danger-border); }

input, select, textarea {
  font: inherit;
  color: var(--fg);
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.45rem 0.6rem;
}
input[type='range'] { padding: 0; }
input[type='checkbox'] { accent-color: var(--accent); }
input[type='color'] { padding: 0.1rem; height: 2rem; }
label { color: var(--fg-dim); font-size: 0.9rem; }

.app-shell { display: flex; flex-direction: column; min-height: 100%; }
.topbar {
  display: flex; align-items: center; gap: 0.75rem;
  padding: 0.8rem 1.2rem;
  border-bottom: 1px solid var(--border);
  background: var(--bg-elev);
}
.topbar .brand { font-weight: 700; font-size: 1.05rem; letter-spacing: 0.02em; }
.topbar .brand .accent { color: var(--accent); }
.topbar nav { display: flex; gap: 0.4rem; flex-wrap: wrap; margin-left: 0.6rem; }
.topbar nav a {
  padding: 0.3rem 0.65rem;
  border-radius: 7px;
  text-decoration: none;
  font-size: 0.88rem;
  color: var(--fg-dim);
}
.topbar nav a.active { background: var(--bg-elev-2); color: var(--fg); }
.topbar .badge {
  margin-left: auto; font-size: 0.72rem; color: var(--fg-dim);
  border: 1px solid var(--border); padding: 0.25rem 0.55rem; border-radius: 999px;
}

main { padding: 1.5rem; max-width: 1080px; margin: 0 auto; width: 100%; }

/* Hero (ADR-0012 A1–A5) — Hub-only, headline + animated SVG illustration. */
.hero {
  display: grid;
  grid-template-columns: 1.4fr 1fr;
  align-items: center;
  gap: 1.4rem;
  padding: 2rem 1.5rem;
  margin-bottom: 1.6rem;
  background: linear-gradient(135deg, var(--bg-elev) 0%, var(--bg-elev-2) 100%);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}
.hero h1 {
  margin: 0 0 0.5rem;
  font-size: clamp(1.6rem, 3vw, 2.2rem);
  line-height: 1.15;
  letter-spacing: -0.01em;
}
.hero h1 .accent { color: var(--accent); }
.hero p {
  margin: 0;
  color: var(--fg-dim);
  max-width: 38ch;
  font-size: 1rem;
}
.hero-illustration {
  display: grid;
  place-items: center;
  min-height: 96px;
}
.hero-svg {
  width: 100%;
  max-width: 320px;
  height: auto;
  color: var(--fg);  /* currentColor for the file glyphs */
}
.hero-svg .file { stroke: currentColor; fill: none; stroke-width: 1.5; stroke-linecap: round; stroke-linejoin: round; }
.hero-svg .file-fold { fill: var(--bg-elev); }
.hero-svg .connector { stroke: var(--fg-dim); stroke-width: 1; stroke-dasharray: 3 4; }
.hero-svg .padlock-body { stroke: var(--accent); fill: var(--bg-elev); stroke-width: 1.5; }
.hero-svg .padlock-shackle { stroke: var(--accent); fill: none; stroke-width: 1.5; stroke-linecap: round; }
.hero-svg .padlock-keyhole { fill: var(--accent); }
.hero-svg .padlock { transform-origin: center; }

/* Gentle 'breathing' opacity pulse on the padlock (ADR-0012 A5 / B7).
   Gated by prefers-reduced-motion so disabled-motion users see static frames. */
@keyframes hero-breathe {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.7; }
}
@media (prefers-reduced-motion: no-preference) {
  .hero-svg .padlock { animation: hero-breathe 4s ease-in-out infinite; }
}

.hub-grid { display: grid; gap: 1rem; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); }
.hub-card {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.1rem;
  text-decoration: none;
  color: inherit;
  display: flex; flex-direction: column; gap: 0.5rem;
  transition: transform 0.1s ease, border-color 0.15s ease, background 0.15s ease;
}
.hub-card:hover { transform: translateY(-2px); border-color: var(--accent); background: var(--bg-elev-2); }
.hub-card .icon { font-size: 1.6rem; }
.hub-card .title { font-weight: 600; }
.hub-card .desc { color: var(--fg-dim); font-size: 0.88rem; min-height: 2.5em; }

.workbench { display: grid; gap: 1.4rem; }
.workbench header h1 { margin: 0 0 0.2rem; font-size: 1.25rem; }
.workbench header p { margin: 0; color: var(--fg-dim); }

.dropzone {
  border: 2px dashed var(--border);
  border-radius: var(--radius);
  padding: 2rem;
  text-align: center;
  background: var(--bg-elev);
  color: var(--fg-dim);
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s;
}
.dropzone.dragover { background: var(--bg-elev-2); border-color: var(--accent); color: var(--fg); }
.dropzone input[type='file'] { display: none; }

.filelist { display: flex; flex-direction: column; gap: 0.3rem; }
.filelist .row {
  display: flex; gap: 0.6rem; align-items: center;
  padding: 0.5rem 0.7rem; background: var(--bg-elev); border: 1px solid var(--border); border-radius: 8px;
  font-size: 0.9rem;
}
.filelist .row .name { flex: 1; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.filelist .row .size { color: var(--fg-dim); font-variant-numeric: tabular-nums; font-size: 0.8rem; }
.filelist .row .rm { background: transparent; border: none; color: var(--fg-dim); padding: 0 0.4rem; }
.filelist .row .rm:hover { color: var(--danger); }

.panel {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem 1.1rem;
  display: grid; gap: 0.85rem;
}
.panel h2 { margin: 0; font-size: 1rem; }
.panel .row { display: grid; gap: 0.3rem; }
.panel .row.two { grid-template-columns: 1fr 1fr; }
.panel .grid2 { display: grid; grid-template-columns: 1fr 1fr; gap: 0.6rem; }

.actions { display: flex; gap: 0.6rem; align-items: center; }
.actions .result { color: var(--fg-dim); font-size: 0.88rem; }
.actions .error { color: var(--danger); }

.preview {
  background: var(--bg-elev); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 1rem; display: grid; place-items: center; min-height: 200px;
}
.preview canvas, .preview img { max-width: 100%; max-height: 50vh; border-radius: 6px; }
.preview .placeholder { color: var(--fg-dim); font-size: 0.9rem; }

.notice {
  border-left: 3px solid var(--accent);
  background: var(--bg-elev);
  padding: 0.7rem 0.9rem;
  border-radius: 6px;
  color: var(--fg-dim);
  font-size: 0.88rem;
}
.notice strong { color: var(--fg); }

.category { margin-top: 0.4rem; font-size: 0.78rem; color: var(--fg-dim); text-transform: uppercase; letter-spacing: 0.06em; }

@media (max-width: 720px) {
  .hero { grid-template-columns: 1fr; padding: 1.4rem 1.1rem; }
  .hero-illustration { order: -1; min-height: 80px; }
  .hero-svg { max-width: 240px; }
}
@media (max-width: 600px) {
  .panel .row.two { grid-template-columns: 1fr; }
  .panel .grid2 { grid-template-columns: 1fr; }
  main { padding: 1rem; }
}

/* Clickable page-number grid for SplitPdf (ADR-0008). */
.page-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(2.4rem, 1fr));
  gap: 0.3rem;
  max-height: 280px;
  overflow-y: auto;
  padding: 0.3rem;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
}
.page-chip {
  font-variant-numeric: tabular-nums;
  font-size: 0.82rem;
  padding: 0.3rem 0;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--fg-dim);
  text-align: center;
  cursor: pointer;
  transition: background 0.1s, border-color 0.1s, color 0.1s;
}
.page-chip:hover { border-color: var(--accent); color: var(--fg); }
.page-chip.selected {
  background: var(--accent);
  color: var(--button-primary-text);
  border-color: var(--accent);
  font-weight: 600;
}