/* 三个内页共用的书页：纸色、墨色、页眉与版心。画面保留自己的颜色。 */
:root {
  color-scheme: light dark;
  --page-bg: #f3efe6;
  --page-ink: #302e29;
  --page-muted: #706b60;
  --page-line: #c9c1b2;
  --page-accent: #874f3e;
  --page-surface: #e9e3d8;
}
* { box-sizing: border-box; }
html { background: var(--page-bg); color: var(--page-ink); }
body.page { margin: 0; background: var(--page-bg); font-family: var(--font-serif); font-size: var(--text-m); line-height: var(--leading); -webkit-font-smoothing: antialiased; }
a { color: inherit; text-underline-offset: 0.25em; text-decoration-thickness: 1px; }
a:hover { color: var(--page-accent); }
button, input, select { font: inherit; }
img { max-width: 100%; }
[hidden] { display: none !important; }
:focus-visible { outline: var(--focus-width) solid currentColor; outline-offset: var(--focus-offset); }
::selection { color: var(--page-bg); background: var(--page-ink); }
.skip-link { position: absolute; left: 1.5rem; top: -6rem; z-index: 20; padding: 0.75rem 1rem; color: var(--page-bg); background: var(--page-ink); font-family: var(--font-sans); }
.skip-link:focus { top: 1rem; }
.page-head, main, .page-foot { width: 100%; max-width: 76rem; margin: 0 auto; padding-inline: 1.5rem; }
.page-masthead { min-height: 6.5rem; display: flex; align-items: center; justify-content: space-between; gap: 1.5rem; border-bottom: 1px solid var(--page-line); }
.site-name { font-size: 1.125rem; letter-spacing: 0.08em; text-decoration: none; white-space: nowrap; }
.site-name span { display: block; font: 0.5625rem/1.6 var(--font-sans); letter-spacing: 0.2em; }
.page-nav { display: flex; align-items: center; flex-wrap: wrap; gap: 0.5rem 1.75rem; font: 0.8125rem/1.5 var(--font-sans); }
.page-nav a { display: inline-block; padding-block: 0.625rem; color: var(--page-muted); text-decoration: none; }
/* 两组：先回到窗前（你这里 · 窗那边），再是三页；中间一道很淡的竖线 */
.nav-group { display: flex; align-items: center; flex-wrap: wrap; gap: 0.5rem 1.75rem; }
.nav-sky { padding-right: 1.75rem; border-right: 1px solid var(--page-line); }
.page-nav a:hover, .page-nav a[aria-current="page"] { color: var(--page-ink); text-decoration: underline; text-underline-offset: 0.6em; }
.page-intro { padding-block: 3.5rem 3rem; }
.eyebrow { margin: 0 0 0.75rem; color: var(--page-muted); font: 0.6875rem/1.6 var(--font-sans); letter-spacing: 0.14em; }
.page-title { margin: 0; font-size: clamp(2.25rem, 4vw, 3.25rem); font-weight: 500; line-height: 1.4; letter-spacing: 0.06em; text-wrap: balance; }
.lede { max-width: 38rem; margin: 1rem 0 0; color: var(--page-muted); line-height: 1.9; }
.page-status { margin: 0; color: var(--page-muted); font: 0.75rem/1.8 var(--font-sans); }
.page-foot { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 0.75rem 2rem; margin-top: 4rem; padding-block: 1.5rem 2.5rem; color: var(--page-muted); font: 0.75rem/1.8 var(--font-sans); }
.page-foot::before { content: ""; width: 100%; border-top: 1px solid var(--page-line); margin-bottom: 0.75rem; }
.page-foot p { margin: 0; }
.page-foot a { text-decoration: none; }
.page-foot a:hover { text-decoration: underline; }
.offscreen { position: fixed; left: -5000px; top: 0; width: 1200px; height: 1500px; overflow: hidden; pointer-events: none; }
@media (prefers-color-scheme: dark) {
  :root { --page-bg: #252622; --page-ink: #e6e0d4; --page-muted: #b5b0a4; --page-line: #57584f; --page-accent: #d6a691; --page-surface: #31332d; }
}
@media (max-width: 620px) {
  .page-masthead { min-height: 6rem; gap: 1rem; }
  .site-name { font-size: 1rem; }
  .site-name span { font-size: 0.5rem; }
  .page-nav { flex-direction: column; align-items: flex-end; gap: 0; font-size: 0.75rem; }
  .page-nav a { padding-block: 0.5rem; }
  .nav-group { gap: 0.375rem 1rem; }
  .nav-sky { padding-right: 0; border-right: 0; }
  .page-intro { padding-block: 2.5rem 2rem; }
  .lede { font-size: 0.9375rem; }
  .page-foot { margin-top: 3rem; }
}
@media (max-width: 359px) {
  .page-head, main, .page-foot { padding-inline: 1rem; }
  .page-masthead { flex-wrap: wrap; justify-content: flex-start; gap: 0; padding-block: 1rem; }
  .page-nav { width: 100%; margin-top: 0.25rem; flex-direction: row; flex-wrap: wrap; justify-content: flex-start; gap: 0 1rem; }
  .nav-sky { padding-right: 1rem; border-right: 1px solid var(--page-line); }
}
@media (prefers-reduced-motion: reduce) { *, *::before, *::after { scroll-behavior: auto !important; } }