:root {
  --bg-top: #f7f4ff;
  --bg-bottom: #eef6ff;
  --ink: #23203a;
  --ink-soft: #6b678a;
  --accent: #6c5ce7;
  --accent-soft: #a29bfe;
  --card: #ffffff;
  --line: rgba(35, 32, 58, 0.08);
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
}

body {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 32px 18px;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  color: var(--ink);
  background: linear-gradient(160deg, var(--bg-top) 0%, var(--bg-bottom) 100%);
  -webkit-font-smoothing: antialiased;
  line-height: 1.75;
}

.wrap {
  width: 100%;
  max-width: 560px;
}

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 20px;
  padding: 32px 26px;
  box-shadow: 0 18px 40px -24px rgba(35, 32, 58, 0.45);
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 6px;
}

.egg {
  font-size: 26px;
  line-height: 1;
}

h1 {
  margin: 0;
  font-size: 26px;
  letter-spacing: 0.5px;
}

.subtitle {
  margin: 6px 0 0;
  color: var(--ink-soft);
  font-size: 15px;
}

.rule {
  height: 1px;
  background: var(--line);
  border: 0;
  margin: 22px 0;
}

.section-title {
  margin: 0 0 10px;
  font-size: 14px;
  letter-spacing: 1px;
  color: var(--ink-soft);
  font-weight: 600;
}

.howto {
  margin: 0 0 18px;
  padding-left: 20px;
  font-size: 15px;
}

.howto li {
  margin: 6px 0;
}

button {
  font: inherit;
  cursor: pointer;
  border-radius: 999px;
  border: 1px solid transparent;
  transition: transform 0.12s ease, opacity 0.12s ease;
}

button:active {
  transform: translateY(1px);
}

.btn-primary {
  width: 100%;
  padding: 14px 20px;
  font-size: 16px;
  font-weight: 600;
  color: #fff;
  background: linear-gradient(135deg, var(--accent) 0%, var(--accent-soft) 100%);
  box-shadow: 0 12px 24px -14px rgba(108, 92, 231, 0.9);
}

.btn-ghost {
  margin-top: 10px;
  width: 100%;
  padding: 10px 20px;
  font-size: 14px;
  color: var(--accent);
  background: transparent;
  border-color: rgba(108, 92, 231, 0.35);
}

.note {
  margin: 14px 0 0;
  font-size: 13px;
  color: var(--ink-soft);
  text-align: center;
}

.prompt-box {
  margin: 0;
  padding: 16px;
  font-size: 14px;
  line-height: 1.85;
  color: var(--ink);
  background: #f8f7ff;
  border: 1px solid var(--line);
  border-radius: 14px;
  white-space: pre-wrap;
  word-break: break-word;
}

/* 给 AI 的隐藏指令块：人眼不可见，但仍在 DOM 与源码中 */
.ai-directive {
  display: none !important;
}

details.manual summary {
  cursor: pointer;
  font-size: 14px;
  color: var(--ink-soft);
  font-weight: 600;
  list-style: revert;
}

details.manual[open] summary {
  margin-bottom: 12px;
}

.meta {
  margin: 0 0 4px;
  font-size: 13px;
  letter-spacing: 2px;
  color: var(--accent);
  font-weight: 600;
}

.question {
  margin: 10px 0 24px;
  font-size: 22px;
  line-height: 1.6;
  font-weight: 600;
}

.back {
  font-size: 15px;
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid rgba(108, 92, 231, 0.4);
}

.foot {
  margin: 18px 0 0;
  font-size: 12px;
  color: var(--ink-soft);
}

.foot a {
  color: var(--accent);
}

code {
  padding: 1px 5px;
  border-radius: 5px;
  background: #f2f1fb;
  font-size: 12px;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}

/* 隐藏题库表格（第二梯队·降级路径）：人看不到，但 DOM 文本提取能读到 */
.ai-bank {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
}

.ai-bank caption {
  text-align: left;
  padding-bottom: 6px;
  color: var(--ink-soft);
}

.ai-bank th,
.ai-bank td {
  border: 1px solid var(--line);
  padding: 4px 8px;
  text-align: left;
  vertical-align: top;
}

button[disabled] {
  opacity: 0.55;
  cursor: not-allowed;
}

@media (max-width: 420px) {
  .card {
    padding: 26px 20px;
  }

  h1 {
    font-size: 23px;
  }

  .question {
    font-size: 19px;
  }
}