:root {
  color-scheme: light;

  /* 色彩 —— 暖纸 / 墨绿 / 陶土橙 */
  --color-paper: oklch(96% 0.014 90);
  --color-paper-2: oklch(92% 0.018 95);
  --color-paper-3: oklch(88% 0.02 95);
  --color-ink: oklch(22% 0.018 145);
  --color-ink-soft: oklch(36% 0.018 145);
  --color-muted: oklch(45% 0.016 145);
  --color-rule: oklch(80% 0.018 100);
  --color-rule-soft: oklch(86% 0.016 100);
  --color-accent: oklch(48% 0.14 50);
  --color-accent-soft: oklch(90% 0.04 50);
  --color-accent-ink: oklch(40% 0.12 45);
  --color-focus: oklch(48% 0.16 50);
  --color-selection: oklch(86% 0.055 50);

  /* 字体 */
  --font-display: "Songti SC", "STSong", "Noto Serif CJK SC", "Source Han Serif SC", serif;
  --font-body: -apple-system, BlinkMacSystemFont, "SF Pro Text", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;

  /* 间距 */
  --space-3xs: 0.125rem;
  --space-2xs: 0.25rem;
  --space-xs: 0.5rem;
  --space-sm: 0.75rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2.5rem;
  --space-2xl: 4rem;
  --space-3xl: 6rem;
  --space-4xl: 9rem;

  /* 字号 */
  --text-xs: 0.8rem;
  --text-sm: 0.9rem;
  --text-base: 1rem;
  --text-md: 1.15rem;
  --text-lg: 1.4rem;
  --text-xl: 1.75rem;
  --text-2xl: 2.2rem;
  --text-display: clamp(2.6rem, 7vw, 4.6rem);

  /* 动效 */
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-in-out: cubic-bezier(0.65, 0, 0.35, 1);
  --dur-micro: 120ms;
  --dur-short: 220ms;
  --dur-long: 420ms;

  /* 形状与布局 */
  --rule-hairline: 1px;
  --radius-small: 0.25rem;
  --radius-medium: 0.75rem;
  --radius-large: 1.25rem;
  --page-gutter: clamp(1.1rem, 4vw, 4rem);
  --page-width: 74rem;
  --prose-width: 42rem;
  --content-width: 60rem;

  --z-base: 1;
  --z-sticky: 200;
  --z-modal: 300;
}

@media (prefers-color-scheme: dark) {
  :root {
    color-scheme: dark;
    --color-paper: oklch(16% 0.018 145);
    --color-paper-2: oklch(19% 0.02 145);
    --color-paper-3: oklch(23% 0.022 145);
    --color-ink: oklch(93% 0.012 90);
    --color-ink-soft: oklch(82% 0.014 90);
    --color-muted: oklch(72% 0.014 110);
    --color-rule: oklch(33% 0.02 145);
    --color-rule-soft: oklch(28% 0.02 145);
    --color-accent: oklch(70% 0.12 50);
    --color-accent-soft: oklch(28% 0.04 50);
    --color-accent-ink: oklch(78% 0.11 50);
    --color-focus: oklch(74% 0.13 50);
    --color-selection: oklch(36% 0.06 50);
  }
}