:root {
  --bg: #f4f6fb;
  --panel: #ffffff;
  --ink: #1f2430;
  --muted: #6b7280;
  --accent: #2563eb;
  --accent-dark: #1d4ed8;
  --border: #d7dbe3;
  --error-bg: #fdecea;
  --error-ink: #b3261e;
  --radius: 12px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.5;
}

header {
  padding: 2rem 1.5rem 1rem;
  text-align: center;
}

header h1 { margin: 0; font-size: 1.8rem; }

.subtitle { color: var(--muted); margin: 0.5rem auto 0; max-width: 640px; }

main {
  max-width: 960px;
  margin: 0 auto;
  padding: 1rem 1.5rem 3rem;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.panel {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.04);
}

.row {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-bottom: 1.25rem;
}

.row label {
  display: flex;
  flex-direction: column;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--muted);
  gap: 0.35rem;
  flex: 1 1 160px;
}

.row select,
.row input {
  font-size: 1rem;
  padding: 0.5rem 0.6rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #fff;
  color: var(--ink);
}

.dropzone {
  border: 2px dashed var(--border);
  border-radius: var(--radius);
  padding: 2.5rem 1rem;
  text-align: center;
  transition: border-color 0.15s, background 0.15s;
  cursor: pointer;
}

.dropzone.dragover {
  border-color: var(--accent);
  background: #eef4ff;
}

.dz-title { font-size: 1.1rem; font-weight: 600; margin: 0 0 0.25rem; }
.dz-or { color: var(--muted); margin: 0.25rem 0; }
.dz-file { margin: 0.75rem 0 0; font-weight: 600; color: var(--accent-dark); }

.actions {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-top: 1.25rem;
}

.status { color: var(--muted); font-size: 0.95rem; }

.btn {
  display: inline-block;
  font-size: 0.95rem;
  font-weight: 600;
  padding: 0.6rem 1.1rem;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: #fff;
  color: var(--ink);
  cursor: pointer;
  text-decoration: none;
  transition: background 0.15s, border-color 0.15s;
}

.btn:hover { background: #f0f2f7; }

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

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

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.error {
  margin-top: 1rem;
  padding: 0.85rem 1rem;
  background: var(--error-bg);
  color: var(--error-ink);
  border-radius: 8px;
  white-space: pre-wrap;
}

.result-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
  margin-bottom: 1rem;
}

.result-header h2 { margin: 0; font-size: 1.3rem; }
.result-actions { display: flex; gap: 0.75rem; }

.groups {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1rem;
}

.group-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.85rem;
  padding: 0.3rem 0.6rem;
  border-radius: 999px;
  border: 1px solid var(--border);
}

.swatch {
  width: 0.9rem;
  height: 0.9rem;
  border-radius: 3px;
  border: 1px solid rgba(0, 0, 0, 0.2);
}

.preview {
  width: 100%;
  height: 75vh;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #fff;
}

.spinner {
  display: inline-block;
  width: 1rem;
  height: 1rem;
  border: 2px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
  vertical-align: -2px;
  margin-right: 0.4rem;
}

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