:root {
  color-scheme: dark;
  font-family: Inter, system-ui, -apple-system, Segoe UI, Roboto, sans-serif;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: radial-gradient(circle at top, #1e293b, #020617 60%);
  color: #e2e8f0;
  min-height: 100vh;
}

.app {
  width: min(1000px, 92vw);
  margin: 0 auto;
  padding: 2rem 0 3rem;
}

h1 { margin: 0 0 0.3rem; }
.subtitle { color: #94a3b8; margin: 0 0 1rem; }

.upload {
  display: inline-block;
  padding: 0.65rem 1rem;
  border-radius: 10px;
  background: #334155;
  cursor: pointer;
  font-weight: 600;
}

input[type="file"] { display: none; }

.actions {
  margin-top: 0.8rem;
  display: flex;
  gap: 0.6rem;
  flex-wrap: wrap;
}

button {
  border: 0;
  border-radius: 10px;
  padding: 0.65rem 1rem;
  background: #2563eb;
  color: white;
  font-weight: 600;
  cursor: pointer;
}
button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.status { margin: 0.9rem 0 1rem; color: #cbd5e1; min-height: 1.4rem; }

.preview-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1rem;
}

.panel {
  background: rgba(15, 23, 42, 0.9);
  border: 1px solid rgba(148, 163, 184, 0.25);
  border-radius: 14px;
  padding: 0.9rem;
}

.panel h2 {
  margin: 0 0 0.7rem;
  font-size: 1rem;
  color: #cbd5e1;
}

.panel img {
  width: 100%;
  min-height: 220px;
  object-fit: contain;
  border-radius: 10px;
  background: #0b1220;
}

.checkered img {
  background-image:
    linear-gradient(45deg, #111827 25%, transparent 25%),
    linear-gradient(-45deg, #111827 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, #111827 75%),
    linear-gradient(-45deg, transparent 75%, #111827 75%);
  background-size: 20px 20px;
  background-position: 0 0, 0 10px, 10px -10px, -10px 0px;
}