:root {
  color-scheme: light dark;
  --bg: #fff;
  --fg: #1a1a1a;
  --muted: #666;
  --border: #ddd;
  --accent: #2563eb;
  --accent-fg: #fff;
  --card-bg: #f7f7f8;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #14161a;
    --fg: #e8e8e8;
    --muted: #9a9a9a;
    --border: #2c2f36;
    --accent: #5b8def;
    --accent-fg: #0b0d10;
    --card-bg: #1b1e24;
  }
}

* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font: 15px/1.5 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

.site-header {
  display: flex;
  align-items: baseline;
  gap: 1rem;
  padding: 1rem 1.5rem;
  border-bottom: 1px solid var(--border);
  flex-wrap: wrap;
}
.brand { font-weight: 700; font-size: 1.1rem; color: var(--fg); text-decoration: none; }
.tagline { color: var(--muted); font-size: 0.85rem; }

.site-footer {
  padding: 2rem 1.5rem;
  color: var(--muted);
  font-size: 0.8rem;
  border-top: 1px solid var(--border);
  margin-top: 3rem;
}

main.home, main.tool {
  max-width: 760px;
  margin: 0 auto;
  padding: 2rem 1.5rem;
}

.back { color: var(--muted); text-decoration: none; font-size: 0.85rem; }
.back:hover { color: var(--accent); }

h1 { font-size: 1.5rem; margin: 0.75rem 0 0.25rem; }
.tool-desc { color: var(--muted); margin-top: 0; }

.category { margin-top: 2rem; }
.category h2 { font-size: 1rem; text-transform: uppercase; letter-spacing: 0.04em; color: var(--muted); border-bottom: 1px solid var(--border); padding-bottom: 0.4rem; }
.tool-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); gap: 0.5rem; list-style: none; margin: 0.75rem 0 0; padding: 0; }
.tool-grid li a {
  display: block;
  padding: 0.6rem 0.8rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--fg);
  text-decoration: none;
  font-size: 0.9rem;
}
.tool-grid li a:hover { border-color: var(--accent); color: var(--accent); }

.tool-body { margin-top: 1.5rem; }

.dropzone {
  border: 2px dashed var(--border);
  border-radius: 10px;
  padding: 2rem 1rem;
  text-align: center;
  color: var(--muted);
  cursor: pointer;
}
.dropzone.drag { border-color: var(--accent); color: var(--accent); }
.dropzone input[type="file"] { display: none; }

.btn {
  background: var(--accent);
  color: var(--accent-fg);
  border: none;
  border-radius: 6px;
  padding: 0.6rem 1.1rem;
  font-size: 0.9rem;
  cursor: pointer;
}
.btn:disabled { opacity: 0.5; cursor: not-allowed; }
.btn.secondary { background: transparent; color: var(--fg); border: 1px solid var(--border); }

textarea, input[type="text"], input[type="number"], select {
  width: 100%;
  padding: 0.6rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--bg);
  color: var(--fg);
  font-family: inherit;
  font-size: 0.9rem;
}
textarea { min-height: 160px; font-family: ui-monospace, SFMono-Regular, Menlo, monospace; resize: vertical; }

.row { display: flex; gap: 0.6rem; align-items: center; flex-wrap: wrap; margin: 0.75rem 0; }

.output {
  margin-top: 1rem;
  padding: 1rem;
  background: var(--card-bg);
  border-radius: 8px;
  overflow: auto;
}
.output img, .output video, .output audio { max-width: 100%; }

.error { color: #dc2626; font-size: 0.85rem; }
.hint { color: var(--muted); font-size: 0.8rem; }

.thumb-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(120px, 1fr)); gap: 0.6rem; }
.thumb-grid figure { margin: 0; }
.thumb-grid img { width: 100%; border-radius: 6px; border: 1px solid var(--border); }
.thumb-grid figcaption { font-size: 0.75rem; color: var(--muted); text-align: center; margin-top: 0.25rem; }