/* MortonLearner 教辅书样式（书页风格：发丝线/留白/页码，无渐变无阴影堆砌） */
* { margin: 0; padding: 0; box-sizing: border-box; }
body {
  font-family: -apple-system, "PingFang SC", "Songti SC", serif;
  background: #eee; color: #1a1a1a; line-height: 1.7;
}
.page {
  background: #fff; border: 1px solid #ccc;
  max-width: 720px; min-height: 90vh;
  margin: 24px auto; padding: 40px 44px;
  box-shadow: 0 1px 3px rgba(0,0,0,.12);
  position: relative;
}
.header { border-bottom: 1px solid #444; padding-bottom: 6px; margin-bottom: 18px; }
.book-title { font-size: 12px; color: #666; }
.chapter { font-size: 19px; font-weight: 700; margin-top: 2px; }
/* 复盘块：五件套 */
.kblock { margin-bottom: 22px; border-top: 1px solid #eee; padding-top: 12px; }
.kblock h3 { font-size: 15px; margin-bottom: 6px; }
.kblock .label { font-weight: 700; font-size: 13px; }
.kblock .kinterp, .kblock .kcheck, .kblock .kexample,
.kblock .kstyle, .kblock .kstandard { margin-bottom: 6px; font-size: 13.5px; }
.kcheck ul { list-style: none; padding-left: 4px; }
.kcheck li { margin: 2px 0; }
.kcheck input[type="checkbox"] { margin-right: 6px; }
.q { border: 1px solid #ddd; padding: 8px 10px; background: #fcfcfc; margin: 4px 0; }
/* 答案折叠：屏幕点开才见 */
details.answer-inline { margin-top: 4px; font-size: 13px; }
details.answer-inline summary { cursor: pointer; color: #555; font-size: 12.5px; }
.expl { color: #666; font-size: 12.5px; margin-top: 2px; }
.boundary { color: #999; font-size: 12px; }
/* 页末答案区：默认隐藏，仅打印显示 */
.appendix { display: none; }
/* 打印样式：答案不直出、勾选恒空白、答案区尾置 */
@media print {
  body { background: #fff; }
  .page { border: none; box-shadow: none; max-width: 100%; margin: 0; padding: 1.2cm; min-height: auto; }
  details.answer-inline { display: none; }        /* 屏幕折叠答案不打印 */
  .appendix { display: block; page-break-before: always; font-size: 12px; }
  .appendix .a-item { margin-bottom: 8px; }
  .kcheck input[type="checkbox"] { -webkit-appearance: none; appearance: none; width: 10px; height: 10px; border: 1px solid #444; display: inline-block; margin-right: 6px; }
  /* 打印时勾选框恒渲染为空白框（屏幕勾选态不打印） */
  .kcheck input[type="checkbox"]:checked { background: #fff; }
}
.footer {
  margin-top: 26px; border-top: 1px solid #ddd; padding-top: 5px;
  font-size: 11px; color: #999; display: flex; justify-content: space-between;
}
.nav { display: flex; justify-content: space-between; margin-top: 10px; font-size: 13px; }
.nav a { color: #333; text-decoration: none; border-bottom: 1px dotted #999; }