body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  margin: 0;
  padding: 16px;
  line-height: 1.6;
  background: #f5f5f5;
}
.container {
  max-width: 640px;
  margin: 0 auto;
  background: #fff;
  padding: 16px 16px 24px;
  box-shadow: 0 2px 6px rgba(0,0,0,0.08);
  box-sizing: border-box;
}
h1 {
  font-size: 1.2rem;
  margin-top: 0;
  border-bottom: 2px solid #eee;
  padding-bottom: .4em;
}
.label-row {
  margin-bottom: 14px;
}
.label-row label {
  display: block;
  margin-bottom: 4px;
  font-size: 0.9rem;
}
input[type="text"], input[type="file"] {
  width: 100%;
  box-sizing: border-box;
  padding: 6px 8px;
  font-size: 1rem;
}
input[type="submit"] {
  margin-top: 10px;
  padding: 8px 20px;
  font-size: 1rem;
}
small {
  color: #666;
}
#file-info {
  margin-top: 4px;
  font-size: 0.9rem;
}
#file-warning {
  margin-top: 2px;
  font-size: 0.9rem;
  color: red;
}