@import "tailwindcss";

/* Dark mode: class-based (for @wrksz/themes) */
@custom-variant dark (&:where(.dark, .dark *));

/* === Design Tokens === */
@theme {
  /* Colors — Light mode defaults */
  --color-canvas: oklch(1 0 0);
  --color-surface: oklch(0.98 0 0);
  --color-ink: oklch(0.08 0 0);
  --color-ink-soft: oklch(0.40 0 0);
  --color-border: oklch(0.92 0 0);
  --color-accent: oklch(0.45 0.18 250);

  /* Fonts — override defaults */
  --font-sans: "Inter", ui-sans-serif, system-ui, sans-serif;
  --font-serif: 'Inter', -apple-system, system-ui, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, monospace;

  /* Typography scale */
  --text-xs: 0.75rem; --text-xs--line-height: 1.2;
  --text-sm: 0.875rem; --text-sm--line-height: 1.4;
  --text-base: 1rem; --text-base--line-height: 1.5;
  --text-lg: 1.125rem; --text-lg--line-height: 1.6;
  --text-xl: 1.25rem; --text-xl--line-height: 1.6;
  --text-2xl: 1.5rem; --text-2xl--line-height: 2rem;
  --text-3xl: 1.875rem; --text-3xl--line-height: 2.25rem;
  --text-4xl: 2.25rem; --text-4xl--line-height: 2.5rem;
  --text-5xl: 3rem; --text-5xl--line-height: 1.1;

  /* Shadows */
  --shadow-card: 0 1px 3px oklch(0 0 0 / 0.08);

  /* Animations */
  --animate-fade-in: fade-in 0.3s ease-out;
  --animate-fade-in-up: fade-in-up 0.4s ease-out;
  --animate-slide-up: slide-up 0.5s ease-out;

  @keyframes fade-in {
    from { opacity: 0; }
    to { opacity: 1; }
  }
  @keyframes fade-in-up {
    from { opacity: 0; transform: translateY(12px); }
    to { opacity: 1; transform: translateY(0); }
  }
  @keyframes slide-up {
    from { opacity: 0; transform: translateY(24px); }
    to { opacity: 1; transform: translateY(0); }
  }
}

@layer base {
  body {
    font-family: var(--font-serif);
    font-weight: 400;
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
  }
  h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-sans);
    font-weight: 700;
    line-height: 1.25;
    letter-spacing: -0.015em;
  }
  h1 { line-height: 1.15; letter-spacing: -0.025em; }
  h2 { line-height: 1.2; letter-spacing: -0.02em; }
  code, pre, kbd, samp {
    font-family: var(--font-mono);
    font-feature-settings: 'liga' 1, 'calt' 1;
  }
  a {
    text-underline-offset: 3px;
    text-decoration-thickness: 1px;
    transition: text-decoration-thickness 0.15s ease;
  }
  a:hover {
    text-decoration-thickness: 3px;
  }
}

/* === Dark mode token overrides === */
.dark {
  --color-canvas: oklch(0 0 0);
  --color-surface: oklch(0.07 0 0);
  --color-ink: oklch(1 0 0);
  --color-ink-soft: oklch(0.72 0 0);
  --color-border: oklch(0.17 0 0);
  --color-accent: oklch(0.68 0.20 250);
  --shadow-card: 0 1px 4px oklch(1 0 0 / 0.06);
}

/* === Blog typography === */
@plugin "@tailwindcss/typography";

@utility prose {
  --tw-prose-body: var(--color-ink-soft);
  --tw-prose-headings: var(--color-ink);
  --tw-prose-links: var(--color-accent);
  --tw-prose-bold: var(--color-ink);
  --tw-prose-quote-borders: var(--color-border);
  --tw-prose-code: var(--color-accent);
  --tw-prose-pre-bg: var(--color-surface);
}

/* === KaTeX dark mode overrides === */
.dark .katex,
.dark .katex * {
  color: currentColor !important;
}
.prose .katex-display {
  color: currentColor !important;
}
.prose .katex-display .katex .base {
  color: currentColor !important;
}
.katex .mfrac .frac-line,
.katex .sqrt .sqrt-line,
.katex .overline .overline-line,
.katex .underline .underline-line {
  border-color: currentColor !important;
}
.katex {
  font-size: 1.1em !important;
}
.katex-display {
  margin: 1.5rem 0;
  overflow-x: auto;
}
.katex .katex-mathml {
  position: absolute;
  clip: rect(1px, 1px, 1px, 1px);
  padding: 0;
  border: 0;
}

/* === Heading utilities === */
@utility heading-xl {
  font-size: 2.25rem;
  font-weight: 800;
  letter-spacing: -0.025em;
  line-height: 1.1;
}

@utility heading-lg {
  font-size: 1.875rem;
  font-weight: 600;
  letter-spacing: -0.025em;
  line-height: 1.2;
}

@utility heading-md {
  font-size: 1.5rem;
  font-weight: 600;
  letter-spacing: -0.025em;
  line-height: 1.3;
}

@utility heading-sm {
  font-size: 1.25rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  line-height: 1.4;
}

/* === Scroll progress bar (CSS animation-timeline + JS fallback) === */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  height: 2px;
  width: 0%;
  background: var(--color-ink);
  z-index: 9999;
  will-change: width;
}

@supports (animation-timeline: scroll()) {
  .scroll-progress {
    width: 0%;
    animation: scroll-progress linear forwards;
    animation-timeline: scroll(root block);
  }
  @keyframes scroll-progress {
    from { width: 0%; }
    to { width: 100%; }
  }
}

/* === Scroll-to-top button === */
.scroll-to-top {
  position: fixed;
  bottom: 24px;
  right: 24px;
  width: 40px;
  height: 40px;
  border: 1px solid var(--color-border);
  border-radius: 50%;
  background: var(--color-canvas);
  color: var(--color-ink);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transform: translateY(10px);
  pointer-events: none;
  transition: opacity 0.3s ease, transform 0.3s ease, border-color 0.2s ease;
  z-index: 9997;
  will-change: opacity, transform;
}
.scroll-to-top.visible {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}
.scroll-to-top:hover {
  border-color: var(--color-ink);
}

/* === Reading progress vertical bar === */
.reading-progress {
  position: fixed;
  right: 12px;
  top: 50%;
  transform: translateY(-50%);
  width: 3px;
  height: 60px;
  background: rgba(0, 0, 0, 0.08);
  border-radius: 2px;
  z-index: 9998;
  overflow: hidden;
}
.reading-progress-fill {
  width: 100%;
  height: 0%;
  background: var(--color-ink);
  border-radius: 2px;
}
@supports (animation-timeline: scroll()) {
  .reading-progress-fill {
    animation: reading-progress linear forwards;
    animation-timeline: scroll(root block);
  }
  @keyframes reading-progress {
    from { height: 0%; }
    to { height: 100%; }
  }
}

/* === Global transition for theme switch === */
* {
  transition: background-color 0.3s ease, color 0.3s ease, border-color 0.3s ease;
}

/* === Reduced motion === */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
  .scroll-progress { display: none; }
}