:root {
  color-scheme: light;
  --ink: #16231f;
  --muted: #586560;
  --paper: #f7f7f3;
  --white: #ffffff;
  --line: #d9ded9;
  --forest: #1f5142;
  --coral: #bc5b3c;
  --marine: #176b7a;
  --gold: #b78527;
  --focus: #0b63ce;
  --radius: 6px;
  --content: 1160px;
  font-family: "Microsoft YaHei", "PingFang SC", "Noto Sans CJK SC", sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; color: var(--ink); background: var(--paper); }
img { display: block; max-width: 100%; }
a { color: inherit; }

.site-header {
  display: flex;
  min-height: 68px;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 10px max(20px, calc((100% - var(--content)) / 2));
  color: #fff;
  background: var(--ink);
}

.site-header > p { margin: 0; color: #dce6e1; font-size: 14px; }
.site-brand { display: inline-flex; align-items: center; gap: 11px; text-decoration: none; }
.site-brand-mark {
  display: grid;
  width: 40px;
  height: 40px;
  place-items: center;
  color: var(--ink);
  background: #f4d77b;
  border-radius: 50%;
  font-family: "STKaiti", "KaiTi", serif;
  font-size: 24px;
  font-weight: 700;
}
.site-brand > span:last-child { display: grid; gap: 2px; }
.site-brand strong { font-family: Georgia, "Times New Roman", serif; font-size: 17px; }
.site-brand small { color: #dce6e1; font-size: 12px; }

main { width: min(100%, var(--content)); margin-inline: auto; padding: 0 20px 72px; }
.catalog-intro {
  display: grid;
  grid-template-columns: minmax(0, 1.25fr) minmax(260px, .75fr);
  gap: 56px;
  align-items: end;
  padding: 64px 0 42px;
  border-bottom: 1px solid var(--line);
}
.eyebrow { margin: 0 0 12px; color: var(--forest); font-size: 13px; font-weight: 800; }
h1, h2, h3 { margin: 0; letter-spacing: 0; }
h1 { max-width: 760px; font-family: "STKaiti", "KaiTi", serif; font-size: 52px; line-height: 1.2; }
.catalog-intro > p { margin: 0; color: var(--muted); font-size: 17px; line-height: 1.9; }

.book { padding-top: 34px; }
.book-heading { display: flex; align-items: end; justify-content: space-between; gap: 24px; margin-bottom: 22px; }
.book-heading h2 { font-size: 28px; }
.book-heading > p { margin: 0; color: var(--muted); font-size: 14px; }
.book-heading > p strong { margin-right: 5px; color: var(--ink); font-size: 24px; }

.lesson-list { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 18px; }
.lesson {
  display: grid;
  grid-template-columns: minmax(160px, .82fr) minmax(0, 1.18fr);
  min-height: 250px;
  overflow: hidden;
  text-decoration: none;
  background: var(--white);
  border: 1px solid var(--line);
  border-top: 5px solid var(--lesson-accent, var(--forest));
  border-radius: var(--radius);
  transition: transform 160ms ease, border-color 160ms ease;
}
.lesson:hover { transform: translateY(-2px); border-color: var(--lesson-accent, var(--forest)); }
.lesson:focus-visible { outline: 3px solid var(--focus); outline-offset: 3px; }
.lesson figure { min-height: 0; margin: 0; background: #e4e8e5; }
.lesson figure img { width: 100%; height: 100%; object-fit: cover; }
.lesson-copy { display: flex; min-width: 0; flex-direction: column; padding: 24px 22px 20px; }
.lesson-meta { display: flex; justify-content: space-between; gap: 12px; margin: 0 0 14px; color: var(--lesson-accent, var(--forest)); font-size: 12px; font-weight: 800; }
.lesson h3 { font-family: "STKaiti", "KaiTi", serif; font-size: 29px; line-height: 1.25; }
.lesson-copy > p:not(.lesson-meta) { margin: 13px 0 22px; color: var(--muted); font-size: 15px; line-height: 1.75; }
.lesson-action { display: flex; justify-content: space-between; gap: 16px; margin-top: auto; font-size: 13px; font-weight: 800; }
.lesson-action b { color: var(--lesson-accent, var(--forest)); font-size: 20px; line-height: 1; }
.lesson-school { --lesson-accent: #285c4c; }
.lesson-flower { --lesson-accent: #bc5b3c; }
.lesson-question { --lesson-accent: #9a6817; }
.lesson-autumn { --lesson-accent: #b85e38; }
.lesson-sea { --lesson-accent: #176b7a; }

.site-footer {
  display: flex;
  justify-content: space-between;
  gap: 30px;
  padding: 24px max(20px, calc((100% - var(--content)) / 2));
  color: #dce6e1;
  background: var(--ink);
  font-size: 12px;
  line-height: 1.7;
}
.site-footer p { max-width: 620px; margin: 0; }
.lesson-sound { --lesson-accent: #526474; }
.lesson-oldhouse { --lesson-accent: #7a5848; }
.lesson-turtle { --lesson-accent: #b66543; }

@media (max-width: 900px) {
  .catalog-intro { grid-template-columns: 1fr; gap: 22px; }
  h1 { font-size: 44px; }
  .lesson-list { grid-template-columns: 1fr; }
}

@media (max-width: 600px) {
  .site-header { min-height: 60px; padding-inline: 16px; }
  .site-header > p { display: none; }
  main { padding-inline: 16px; padding-bottom: 48px; }
  .catalog-intro { padding: 40px 0 30px; }
  h1 { font-size: 38px; }
  .catalog-intro > p { font-size: 16px; }
  .book-heading { align-items: start; }
  .lesson { grid-template-columns: 1fr; min-height: 0; }
  .lesson figure { aspect-ratio: 16 / 9; }
  .lesson-copy { padding: 20px 18px; }
  .lesson h3 { font-size: 27px; }
  .site-footer { display: block; padding-inline: 16px; }
  .site-footer p + p { margin-top: 8px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .lesson { transition: none; }
}