:root {
 --color-paper: oklch(98.8% .008 233); /* #F8FCFF */
 --color-book: oklch(95.6% .015 83); /* ivory paper */
 --color-ink: oklch(39.9% .091 244); /* #0F4C75 */
 --color-heading: oklch(26% .04 250);
 --color-muted: oklch(43% .048 245);
 --color-accent: oklch(75.3% .139 233); /* #38BDF8 */
 --color-accent-ink: oklch(25% .055 245);
 --color-yellow: oklch(92.4% .12 95); /* #FDE68A */
 --color-red: oklch(52% .16 29);
 --color-rule: oklch(83% .027 238);
 --color-dark: oklch(24% .051 247);
 --color-dark-rule: oklch(45% .04 246);
 --color-white: oklch(99% .004 230);
 --color-overlay: oklch(19% .04 248 / .84);
 --color-image-shade: oklch(19% .04 248 / .13);
 --color-shadow: oklch(27% .04 247 / .13);
 --color-error: oklch(46% .17 28);
 --color-success: oklch(37% .085 155);
 --color-focus: oklch(30% .085 245);
 --font-display: 'Noto Serif SC','Songti SC','STSong',serif;
 --font-body: 'Noto Sans SC','PingFang SC','Microsoft YaHei',sans-serif;
 --space-xs: 4px; --space-sm: 8px; --space-md: 16px; --space-lg: 24px; --space-xl: 32px; --space-2xl: 48px; --space-3xl: 80px; --space-4xl: 112px;
 --text-small: .875rem; --text-body: 1rem; --text-display: clamp(3.2rem,6.3vw,6.1rem);
 --ease-out: cubic-bezier(.16,1,.3,1); --ease-in: cubic-bezier(.7,0,.84,0); --ease-in-out: cubic-bezier(.65,0,.35,1);
 --dur-fast: 160ms; --dur-normal: 300ms; --rule-hair: 1px; --radius-sm: 3px;
}