/* ============================================================
   Cascade layers — order determines specificity priority
   ============================================================ */
@layer reset, base, layout, components, utilities;

/* ============================================================
   Design tokens
   ============================================================ */
:root {
  /* Colours — light scheme */
  --color-bg: oklch(99% 0 0);
  --color-surface: oklch(96% 0.005 250);
  --color-text: oklch(15% 0.01 250);
  --color-text-muted: oklch(45% 0.01 250);
  --color-accent: oklch(55% 0.18 250);
  --color-accent-hover: oklch(45% 0.18 250);
  --color-border: oklch(85% 0.01 250);
  --color-code-bg: oklch(93% 0.005 250);

  /* Typography */
  --font-sans: system-ui, sans-serif;
  --font-mono: ui-monospace, "Cascadia Code", "Source Code Pro", monospace;
  --font-size-sm: clamp(0.8rem, 0.17vw + 0.76rem, 0.89rem);
  --font-size-base: clamp(1rem, 0.34vw + 0.91rem, 1.19rem);
  --font-size-lg: clamp(1.25rem, 0.61vw + 1.1rem, 1.58rem);
  --font-size-xl: clamp(1.56rem, 1vw + 1.31rem, 2.11rem);
  --font-size-2xl: clamp(1.95rem, 1.56vw + 1.56rem, 2.81rem);
  --line-height: 1.65;
  --line-height-heading: 1.2;

  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 2rem;
  --space-xl: 4rem;

  /* Layout */
  --content-width: 68ch;
  --site-padding: clamp(1rem, 4vw, 2rem);

  /* Transitions */
  --transition-fast: 150ms ease;
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: oklch(12% 0.01 250);
    --color-surface: oklch(18% 0.01 250);
    --color-text: oklch(92% 0.005 250);
    --color-text-muted: oklch(65% 0.01 250);
    --color-accent: oklch(72% 0.18 250);
    --color-accent-hover: oklch(82% 0.18 250);
    --color-border: oklch(30% 0.01 250);
    --color-code-bg: oklch(20% 0.01 250);
  }
}

/* ============================================================
   Reset
   ============================================================ */
@layer reset {
  *,
  *::before,
  *::after {
    box-sizing: border-box;
  }

  html {
    -webkit-text-size-adjust: none;
    text-size-adjust: none;
  }

  body {
    margin: 0;
  }

  img,
  video,
  svg {
    display: block;
    max-inline-size: 100%;
  }

  h1,
  h2,
  h3,
  h4,
  p,
  figure,
  blockquote,
  dl,
  dd {
    margin: 0;
  }

  ul[role="list"],
  ol[role="list"] {
    list-style: none;
    padding: 0;
    margin: 0;
  }

  input,
  button,
  textarea,
  select {
    font: inherit;
  }
}

/* ============================================================
   Base
   ============================================================ */
@layer base {
  html {
    color-scheme: light dark;
    scroll-behavior: smooth;
    font-size: 100%;
  }

  body {
    font-family: var(--font-sans);
    font-size: var(--font-size-base);
    line-height: var(--line-height);
    color: var(--color-text);
    background-color: var(--color-bg);
    min-block-size: 100dvh;
    display: grid;
    grid-template-rows: auto 1fr auto;
  }

  h1,
  h2,
  h3,
  h4,
  h5,
  h6 {
    line-height: var(--line-height-heading);
    text-wrap: balance;
  }

  p {
    text-wrap: pretty;
  }

  a {
    color: var(--color-accent);
    transition: color var(--transition-fast);

    &:hover {
      color: var(--color-accent-hover);
    }

    &:focus-visible {
      outline: 2px solid var(--color-accent);
      outline-offset: 3px;
      border-radius: 2px;
    }
  }

  code {
    font-family: var(--font-mono);
    font-size: 0.875em;
    background-color: var(--color-code-bg);
    padding-block: 0.1em;
    padding-inline: 0.35em;
    border-radius: 4px;
  }

  pre {
    background-color: var(--color-code-bg);
    border: 1px solid var(--color-border);
    border-radius: 8px;
    padding: var(--space-md);
    overflow-x: auto;

    & code {
      background: none;
      padding: 0;
      font-size: var(--font-size-sm);
    }
  }

  blockquote {
    border-inline-start: 3px solid var(--color-accent);
    padding-inline-start: var(--space-lg);
    color: var(--color-text-muted);
    font-style: italic;
  }

  hr {
    border: none;
    border-block-start: 1px solid var(--color-border);
    margin-block: var(--space-xl);
  }
}

/* ============================================================
   Layout
   ============================================================ */
@layer layout {
  .site-header {
    border-block-end: 1px solid var(--color-border);
    padding-block: var(--space-md);
    padding-inline: var(--site-padding);
  }

  main {
    padding-block: var(--space-xl);
    padding-inline: var(--site-padding);
    max-inline-size: calc(var(--content-width) + 2 * var(--site-padding));
    margin-inline: auto;
    inline-size: 100%;
  }

  .site-footer {
    border-block-start: 1px solid var(--color-border);
    padding-block: var(--space-lg);
    padding-inline: var(--site-padding);
    color: var(--color-text-muted);
    font-size: var(--font-size-sm);
    text-align: center;
  }
}

/* ============================================================
   Components
   ============================================================ */
@layer components {
  /* Navigation */
  .site-nav {
    display: flex;
    align-items: center;
    gap: var(--space-lg);
    max-inline-size: calc(var(--content-width) + 2 * var(--site-padding));
    margin-inline: auto;
  }

  .site-nav__home {
    font-weight: 600;
    text-decoration: none;
    color: var(--color-text);
    margin-inline-end: auto;

    &:hover {
      color: var(--color-accent);
    }
  }

  .site-nav__links {
    display: flex;
    gap: var(--space-lg);
    list-style: none;
    margin: 0;
    padding: 0;
  }

  /* Hero */
  .hero {
    margin-block-end: var(--space-xl);
  }

  .hero__title {
    font-size: var(--font-size-2xl);
    margin-block-end: var(--space-sm);
  }

  .hero__lead {
    font-size: var(--font-size-lg);
    color: var(--color-text-muted);
  }

  /* Post list */
  .post-list {
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
  }

  .post-list--full {
    gap: var(--space-lg);
  }

  .post-list__item {
    display: contents;
  }

  .post-list--full .post-list__item {
    display: flex;
    flex-direction: column;
    gap: var(--space-xs);
  }

  .post-list__link {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    gap: var(--space-md);
    text-decoration: none;
    padding-block: var(--space-xs);

    &:hover .post-list__title {
      text-decoration: underline;
    }

    &:focus-visible {
      outline: 2px solid var(--color-accent);
      outline-offset: 3px;
      border-radius: 2px;
    }
  }

  .post-list__title {
    color: var(--color-text);
    font-weight: 500;
  }

  .post-list__date {
    color: var(--color-text-muted);
    font-size: var(--font-size-sm);
    white-space: nowrap;
    flex-shrink: 0;
  }

  .post-list__description {
    color: var(--color-text-muted);
    font-size: var(--font-size-sm);
    margin: 0;
  }

  .link-more {
    display: inline-block;
    margin-block-start: var(--space-md);
    font-size: var(--font-size-sm);
  }

  /* Blog post */
  .post__header {
    margin-block-end: var(--space-xl);
  }

  .post__title {
    font-size: var(--font-size-2xl);
    margin-block-end: var(--space-sm);
  }

  .post__meta {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: var(--space-sm);
    color: var(--color-text-muted);
    font-size: var(--font-size-sm);
  }

  .post__description {
    margin-block-start: var(--space-md);
    font-size: var(--font-size-lg);
    color: var(--color-text-muted);
  }

  .post__tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-xs);
  }

  .tag {
    background-color: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: 4px;
    padding-block: 0.1em;
    padding-inline: 0.5em;
    font-size: var(--font-size-sm);
  }

  /* Prose — rich text body */
  .prose {
    container-type: inline-size;

    & > * + * {
      margin-block-start: var(--space-md);
    }

    & h2 {
      font-size: var(--font-size-xl);
      margin-block-start: var(--space-xl);
      margin-block-end: var(--space-sm);
    }

    & h3 {
      font-size: var(--font-size-lg);
      margin-block-start: var(--space-lg);
      margin-block-end: var(--space-sm);
    }

    & ul,
    & ol {
      padding-inline-start: var(--space-lg);
    }

    & li + li {
      margin-block-start: var(--space-xs);
    }

    & blockquote {
      margin-inline: 0;
      margin-block: var(--space-lg);
    }

    & pre {
      margin-block: var(--space-lg);
    }

    & a {
      text-decoration: underline;
      text-underline-offset: 0.2em;
    }

    & img {
      border-radius: 8px;
      margin-inline: auto;
    }

    & figure {
      margin-inline: 0;

      & figcaption {
        text-align: center;
        color: var(--color-text-muted);
        font-size: var(--font-size-sm);
        margin-block-start: var(--space-xs);
      }
    }

    @container (width > 40ch) {
      & blockquote {
        padding-inline-start: var(--space-xl);
      }
    }
  }

  /* Page header */
  .page-header {
    margin-block-end: var(--space-xl);

    & h1 {
      font-size: var(--font-size-2xl);
    }
  }

  /* Recent posts section */
  /* 404 page */
  .error-page {
    text-align: center;
    padding-block: var(--space-xl);

    & h1 {
      font-size: var(--font-size-2xl);
      margin-block-end: var(--space-md);
    }

    & p {
      color: var(--color-text-muted);
      margin-block-end: var(--space-lg);
    }
  }

  .recent-posts {
    & h2 {
      font-size: var(--font-size-lg);
      margin-block-end: var(--space-md);
      color: var(--color-text-muted);
      text-transform: uppercase;
      letter-spacing: 0.05em;
      font-size: var(--font-size-sm);
    }
  }
}

/* ============================================================
   Utilities
   ============================================================ */
@layer utilities {
  .visually-hidden {
    clip: rect(0 0 0 0);
    clip-path: inset(50%);
    block-size: 1px;
    inline-size: 1px;
    overflow: hidden;
    white-space: nowrap;
    position: absolute;
  }
}