body {
  font-family: 'Zen Maru Gothic', sans-serif;
  margin: 0;
  padding: 0;
  background-color: #fffef6;
  color: #333;
  transition: background 0.3s ease;
}
@media (prefers-color-scheme: dark) {
  body {
    background-color: #1c1c1e;
    color: #f0f0f0;
  }
}
.container {
  max-width: 600px;
  margin: 80px auto;
  background: rgba(255,255,255,0.5);
  backdrop-filter: blur(2px);
  border-radius: 16px;
  padding: 24px;
  position: relative;
  z-index: 10;
  box-shadow: 0 10px 30px rgba(0,0,0,0.1);
}
.bg-layer {
  background: url('/images/hero-illustration.png') no-repeat center center / cover;
  position: fixed;
  top: 0; left: 0; width: 100%; height: 100%;
  opacity: 0.12;
  z-index: 1;
  pointer-events: none;
  animation: moveBg 60s linear infinite;
}
@keyframes moveBg {
  from { background-position: center top; }
  to { background-position: center bottom; }
}
.upload-btn {
  margin-top: 12px;
  padding: 10px 20px;
  font-size: 15px;
  border: none;
  border-radius: 8px;
  background-color: #28a745;
  color: #fff;
  cursor: pointer;
  display: block;
  width: 100%;
  box-sizing: border-box;
}
.upload-btn:hover {
  background-color: #218838;
}
.drop-zone {
  border: 2px dashed #28a745;
  border-radius: 12px;
  padding: 30px;
  text-align: center;
  background-color: #f6fff8;
  cursor: pointer;
  transition: background-color 0.3s ease;
}
input[type="password"] {
  margin-top: 12px;
  padding: 10px;
  font-size: 14px;
  border-radius: 8px;
  border: 1px solid #ccc;
  width: 100%;
  box-sizing: border-box;
}
.progress {
  margin-top: 10px;
  height: 14px;
  width: 100%;
  background: #e9ecef;
  border-radius: 8px;
  overflow: hidden;
}
.progress-bar {
  height: 100%;
  background: #28a745;
  width: 0%;
  transition: width 0.3s ease;
}
.message {
  margin-top: 20px;
  font-size: 14px;
}
.link-box {
  word-break: break-word;
  background: #f8f9fa;
  padding: 10px;
  border-radius: 6px;
  margin-top: 15px;
}
.usage-guide {
  margin-top: 60px;
  padding: 20px;
  background: #f8f9fa;
  border-radius: 12px;
  box-shadow: 0 0 10px rgba(0,0,0,0.05);
}
.usage-guide h2 {
  margin-top: 0;
  font-size: 20px;
}
.usage-guide ol {
  padding-left: 20px;
}