body {
  font-family: system-ui, -apple-system, sans-serif;
  max-width: 640px;
  margin: 0 auto;
  padding: 16px;
  line-height: 1.6;
  color: #1f2937;
}
header { text-align: center; padding: 24px 0; }
h1 { font-size: 24px; margin: 0 0 8px; }
h2 { font-size: 18px; margin: 0 0 12px; }
h3 { font-size: 16px; margin: 16px 0 8px; }
section {
  margin: 32px 0;
  padding: 16px;
  border: 1px solid #e5e7eb;
  border-radius: 8px;
}
.hidden { display: none; }
.board { background: #f6f8fa; padding: 16px; border-radius: 8px; font-size: 18px; }
fieldset { border: none; margin: 12px 0; padding: 0; }
legend { font-weight: 600; margin-bottom: 8px; }
label { display: block; padding: 6px 0; cursor: pointer; }
input[type="text"], input:not([type]) {
  padding: 6px 8px;
  border: 1px solid #d1d5db;
  border-radius: 4px;
  font-size: 16px;
  width: 160px;
}
button {
  padding: 10px 16px;
  font-size: 16px;
  cursor: pointer;
  background: #2563eb;
  color: #fff;
  border: none;
  border-radius: 6px;
  margin-top: 12px;
}
button:hover { background: #1d4ed8; }
button:disabled { background: #9ca3af; cursor: not-allowed; }
.result { margin-top: 12px; padding: 8px 12px; background: #eef2ff; border-radius: 6px; }
audio { width: 100%; margin: 12px 0; }

table { width: 100%; border-collapse: collapse; margin: 12px 0; }
th, td { padding: 8px; border: 1px solid #e5e7eb; text-align: center; }
.cta {
  display: inline-block;
  margin-top: 16px;
  padding: 12px 20px;
  background: #2563eb;
  color: #fff;
  text-decoration: none;
  border-radius: 6px;
}
table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 16px;
}
th, td {
  padding: 10px;
  text-align: left;
  border-bottom: 1px solid #e5e7eb;
}
th {
  background-color: #f9fafb;
  font-weight: 600;
  color: #374151;
}
/* 让每个 section 变成独立的一页 */
section {
  display: none; /* 默认全隐藏，由 JS 控制显示 */
  min-height: 80vh; /* 最少占屏幕 80% 高度，垂直居中 */
  display: flex;
  flex-direction: column;
  justify-content: center;
  animation: fadeIn 0.5s ease-in-out;
}

/* 当 JS 移除了 hidden 类，才显示 */
section:not(.hidden) {
  display: flex;
}

/* 丝滑的淡入动画 */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}