/* Atlas of Physics: shared tokens (Anatomy light theme). */
:root {
  --page: #f2f2ef; --card: #fbfbfa; --text: #57575a; --strong: #18181a; --muted: #8c8c90;
  --hi: #26262a; --mid: #8a8a8f; --lo: #b4b4b8; --faint: #d4d4d6; --lit: #000;
  --red: #e5484d;
  --serif: 'EB Garamond', Georgia, 'Songti SC', 'Noto Serif SC', 'Source Han Serif SC', serif; --sans: 'Inter', system-ui, 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', 'Noto Sans SC', sans-serif; --mono: 'JetBrains Mono', ui-monospace, 'PingFang SC', 'Microsoft YaHei', monospace;
  --lift: inset 0 1px 0 0 #fff, 0 0 0 1px #0000000f, 0 1px 1px -.5px #0000000a, 0 3px 3px -1.5px #0000000a, 0 6px 6px -3px #0000000a, 0 12px 12px -6px #0000000a, 0 24px 24px -12px #0000000a;
}
* { box-sizing: border-box; margin: 0; }
html { background: var(--page); color: var(--text); font: 15px/1.6 var(--sans); -webkit-font-smoothing: antialiased; }
/* 中文字体没有斜体，不让浏览器把汉字压成假斜体 */
html { font-synthesis-style: none; }
body { background: var(--page); }
a { color: inherit; }
:focus-visible { outline: 2px solid var(--hi); outline-offset: 3px; }

/* Page to page: a soft crossfade, under the book opening from its card and closing into it (engine/cover.js). */
@view-transition { navigation: auto; }
@media (prefers-reduced-motion: reduce) { @view-transition { navigation: none; } }
/* The book and the contents page around it move with engine/cover.js, which animates these itself. The cover (the
   card's picture) and the pages swing about the spine, showing one side; the cover sits over the opening book. */
html.book-vt::view-transition-old(root), html.book-vt::view-transition-new(root), ::view-transition-new(book),
::view-transition-old(cover), ::view-transition-new(cover), ::view-transition-old(left), ::view-transition-old(right) { animation: none; mix-blend-mode: normal; backface-visibility: hidden; }
html.book-vt::view-transition-old(root), html.book-vt::view-transition-new(root) { transform-origin: 0 0; }
::view-transition-old(cover), ::view-transition-new(cover), ::view-transition-old(right) { transform-origin: 0 50%; }
::view-transition-old(left) { transform-origin: 100% 50%; }
::view-transition-group(cover) { z-index: 1; }