:root {
  --primary: #3498db;
  --secondary: #2c3e50;
  --bg: #f4f6f8;
  --card-bg: #fff;
  --radius: 8px;
}

body {
  font-family: 'Segoe UI', Roboto, sans-serif;
  margin: 0;
  background: var(--bg);
  color: var(--secondary);
  line-height: 1.5;
}

/* Header with hero background */
.header {
  background: var(--secondary);
  color: #fff;
  text-align: center;
  padding: 2rem 1rem;
  position: relative;
}

.brand-logo {
  height: 60px;
  margin-bottom: 1rem;
}

/* Full-width hero banner */
.hero-banner {
  width: 100%;
  height: auto;
  display: block;
  margin: 0;
  border-radius: 0;
}

/* Main container */
.container {
  max-width: 900px;
  margin: auto;
  padding: 2rem;
}

h2 {
  margin-bottom: 1rem;
  border-bottom: 2px solid #ddd;
  padding-bottom: 0.5rem;
}

.upload {
  margin-bottom: 2rem;
}

/* Drag & drop zone */
.drop-zone {
  border: 2px dashed var(--primary);
  border-radius: var(--radius);
  padding: 2rem;
  text-align: center;
  cursor: pointer;
  background: #eaf4fc;
  transition: background 0.3s, border-color 0.3s;
}

.drop-zone.dragover {
  background: #d0e9ff;
  border-color: #2980b9;
}

/* Primary button */
.btn-primary {
  background: var(--primary);
  color: #fff;
  border: none;
  padding: 0.8rem 1.5rem;
  border-radius: var(--radius);
  cursor: pointer;
  margin-top: 1rem;
  font-size: 1rem;
  transition: background 0.3s, transform 0.2s;
}

.btn-primary:hover {
  background: #2980b9;
  transform: translateY(-2px);
}

/* Report grid */
.report-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  gap: 1rem;
}

.report-card {
  background: var(--card-bg);
  border-radius: var(--radius);
  padding: 1rem;
  box-shadow: 0 2px 6px rgba(0,0,0,0.1);
  transition: transform 0.2s, box-shadow 0.2s;
}

.report-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}

.report-card h3 {
  margin-top: 0;
  color: var(--primary);
}

.timestamp {
  font-size: 0.8rem;
  color: #888;
}

/* Empty state for reports */
.report-grid:empty::before {
  content: "No reports generated yet.";
  display: block;
  text-align: center;
  color: #666;
  font-style: italic;
  padding: 1rem;
}

/* Footer */
.footer {
  text-align: center;
  padding: 1rem;
  background: #eee;
  margin-top: 2rem;
  font-size: 0.9rem;
  color: #555;
}

/* Responsive tweaks */
@media (max-width: 600px) {
  .container {
    padding: 1rem;
  }
  .drop-zone {
    padding: 1.5rem;
  }
  .btn-primary {
    width: 100%;
  }
}