:root {
  --bg: #f4f5f7;
  --card: #ffffff;
  --ink: #1f2937;
  --muted: #6b7280;
  --primary: #4f46e5;
  --primary-dark: #4338ca;
  --border: #e5e7eb;
  --danger: #dc2626;
}
* { box-sizing: border-box; }
body {
  margin: 0; font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  background: var(--bg); color: var(--ink);
}
.hidden { display: none !important; }
.muted { color: var(--muted); }
.small { font-size: .85rem; }
.error { color: var(--danger); font-weight: 600; }

/* ---------- auth ---------- */
#view-auth { display: flex; justify-content: center; padding: 4rem 1rem; }
.auth-card {
  background: var(--card); border: 1px solid var(--border); border-radius: 12px;
  padding: 2rem; max-width: 420px; width: 100%;
}
.auth-card h1 { margin-top: 0; }
.tabs { display: flex; gap: .5rem; margin: 1rem 0; }
.tab {
  flex: 1; padding: .6rem; border: 1px solid var(--border); background: #f9fafb;
  border-radius: 8px; cursor: pointer; font-weight: 600;
}
.tab.active { background: var(--primary); color: #fff; border-color: var(--primary); }

/* ---------- layout ---------- */
.topbar {
  display: flex; justify-content: space-between; align-items: center;
  background: var(--card); border-bottom: 1px solid var(--border);
  padding: .8rem 1.2rem; position: sticky; top: 0; z-index: 10;
}
.layout {
  display: grid; grid-template-columns: 1fr 340px; gap: 1rem;
  max-width: 1200px; margin: 0 auto; padding: 1rem;
}
@media (max-width: 900px) { .layout { grid-template-columns: 1fr; } }
.card {
  background: var(--card); border: 1px solid var(--border); border-radius: 12px;
  padding: 1.2rem; margin-bottom: 1rem;
}
.card h2 { margin: 0 0 .8rem; font-size: 1.1rem; }

/* ---------- forms ---------- */
label { display: block; margin: .6rem 0; font-weight: 600; }
input[type="text"], input[type="password"], input[type="search"], textarea {
  width: 100%; padding: .6rem; margin-top: .3rem;
  border: 1px solid var(--border); border-radius: 8px; font: inherit;
}
textarea { resize: vertical; }
input[type="file"] { margin: .4rem 0; }
.btn {
  display: inline-block; padding: .6rem 1.1rem; border-radius: 8px;
  border: 1px solid var(--border); background: #fff; cursor: pointer;
  font: inherit; font-weight: 600; text-decoration: none; color: var(--ink);
}
.btn.primary { background: var(--primary); border-color: var(--primary); color: #fff; }
.btn.primary:hover { background: var(--primary-dark); }
.btn.big { width: 100%; padding: .9rem; font-size: 1.05rem; margin-bottom: 1rem; }
.btn.small { padding: .35rem .7rem; font-size: .85rem; }
.row { display: flex; gap: .6rem; flex-wrap: wrap; margin-top: .8rem; }

/* ---------- presets ---------- */
#preset-search { margin-bottom: .8rem; }
.preset-cat { border: 1px solid var(--border); border-radius: 8px; margin-bottom: .5rem; overflow: hidden; }
.preset-cat > button {
  width: 100%; text-align: left; padding: .7rem .9rem; background: #f9fafb;
  border: 0; cursor: pointer; font: inherit; font-weight: 700;
  display: flex; justify-content: space-between; align-items: center;
}
.preset-cat > button::after { content: "▸"; color: var(--muted); }
.preset-cat.open > button::after { content: "▾"; }
.preset-list { display: none; padding: .5rem; }
.preset-cat.open .preset-list { display: block; }
.preset-btn {
  display: block; width: 100%; text-align: left; margin: .3rem 0;
  padding: .55rem .7rem; border: 1px solid var(--border); border-radius: 8px;
  background: #fff; cursor: pointer; font: inherit;
}
.preset-btn:hover { border-color: var(--primary); background: #eef2ff; }
.preset-btn .mask-hint { color: var(--muted); font-size: .8rem; }

/* ---------- preview / result ---------- */
#preview-wrap img, .compare img {
  max-width: 100%; border-radius: 8px; border: 1px solid var(--border);
}
#preview-wrap { margin-top: .6rem; }
.compare { display: grid; grid-template-columns: 1fr 1fr; gap: .8rem; }
.compare figure { margin: 0; }
.compare figcaption { text-align: center; color: var(--muted); font-size: .85rem; margin-top: .3rem; }
@media (max-width: 600px) { .compare { grid-template-columns: 1fr; } }

/* ---------- history ---------- */
.history-grid { display: grid; grid-template-columns: 1fr 1fr; gap: .6rem; }
.hist-item {
  border: 1px solid var(--border); border-radius: 8px; overflow: hidden;
  cursor: pointer; background: #fff;
}
.hist-item img { width: 100%; aspect-ratio: 1; object-fit: cover; display: block; }
.hist-item .hist-meta { padding: .4rem .5rem; font-size: .75rem; color: var(--muted); }
.hist-item.failed { opacity: .55; }

/* ---------- loading ---------- */
#loading { text-align: center; padding: 1.5rem; }
.spinner {
  width: 40px; height: 40px; margin: 0 auto .8rem;
  border: 4px solid var(--border); border-top-color: var(--primary);
  border-radius: 50%; animation: spin 1s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }