/* ==========================================================================
   mitchellcook.dev — implements docs/design-system.md
   Monochrome, system-font, auto light/dark. Tokens → base → components.
   ========================================================================== */

/* --------------------------------------------------------------------------
   Tokens
   -------------------------------------------------------------------------- */
:root {
  /* Color — light defaults; dark overrides in the media query below.
     Referenced by role only (--fg/--bg/…), never by raw value. */
  --bg: #ffffff;
  --fg: #111111;
  --muted: #6a6a6a;
  --border: rgba(0, 0, 0, 0.12);

  /* Type — system stacks only, no web fonts */
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica,
    Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas,
    monospace;
  --text-hero: clamp(2.5rem, 8vw, 4rem);
  --text-h2: 1.4rem;
  --text-lg: 1.2rem;
  --text-base: 1rem;
  --text-sm: 0.9rem;

  /* Spacing scale */
  --space-1: 0.5rem;
  --space-2: 1rem;
  --space-3: 1.5rem;
  --space-4: 2rem;
  --space-6: 3rem;
  --space-8: 5rem;

  /* Primitives */
  --radius: 0.5rem;
  --radius-sm: 0.25rem;
  --measure: 44rem; /* prose reading column (~70–80ch) */
  --measure-wide: 60rem; /* opt-in wide content */
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0a0a0a;
    --fg: #f2f2f2;
    --muted: #9a9a9a;
    --border: rgba(255, 255, 255, 0.14);
  }
}

/* --------------------------------------------------------------------------
   Base
   -------------------------------------------------------------------------- */
* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font);
  font-size: var(--text-base);
  line-height: 1.65;
  color: var(--fg);
  background: var(--bg); /* flat — no gradient */
  min-height: 100vh;
}

/* Reading column — header, main, footer, and any .container share the measure */
.container,
.site-header,
main,
.site-footer {
  max-width: var(--measure);
  margin-inline: auto;
}

/* Opt-in wide variant for demos / media / code output */
.container--wide {
  max-width: var(--measure-wide);
}

h1,
h2,
h3 {
  line-height: 1.2;
}

h2 {
  font-size: var(--text-h2);
  margin: 0 0 0.75rem;
}

h3 {
  font-size: var(--text-lg);
  margin: 0 0 var(--space-1);
}

p {
  margin: 0 0 var(--space-2);
}

/* --------------------------------------------------------------------------
   Utilities
   -------------------------------------------------------------------------- */
.muted {
  color: var(--muted);
}

/* Skip-to-content — visually hidden until focused */
.skip-link {
  position: absolute;
  left: var(--space-3);
  top: -4rem;
  z-index: 10;
  padding: var(--space-1) var(--space-2);
  color: var(--bg);
  background: var(--fg);
  border-radius: var(--radius-sm);
  text-decoration: none;
  transition: top 150ms ease;
}

.skip-link:focus {
  top: var(--space-3);
}

/* --------------------------------------------------------------------------
   Link
   -------------------------------------------------------------------------- */
a {
  color: var(--fg); /* monochrome — same as body text */
  text-decoration: underline;
  text-underline-offset: 0.15em;
  text-decoration-thickness: 1px;
  transition: text-decoration-thickness 150ms ease;
}

a:hover {
  text-decoration-thickness: 2px; /* emphasis via weight of the line, not hue */
}

/* Visible focus for every interactive element */
a:focus-visible,
button:focus-visible,
.btn:focus-visible,
input:focus-visible,
textarea:focus-visible,
select:focus-visible {
  outline: 2px solid var(--fg);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

/* --------------------------------------------------------------------------
   Code
   -------------------------------------------------------------------------- */
code,
pre {
  font-family: var(--font-mono);
  font-size: 0.95em;
}

/* Inline code — subtle hairline chip */
:not(pre) > code {
  padding: 0.1rem 0.35rem;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
}

/* Code block */
pre {
  margin: var(--space-3) 0;
  padding: var(--space-2);
  overflow-x: auto;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  line-height: 1.5;
}

pre code {
  padding: 0;
  border: 0;
}

/* --------------------------------------------------------------------------
   Header + Nav
   -------------------------------------------------------------------------- */
.site-header {
  padding: var(--space-4) var(--space-3) 0;
}

.nav__list {
  display: flex;
  flex-wrap: wrap; /* collapses gracefully — wraps on narrow screens, no JS */
  gap: var(--space-1) var(--space-3);
  margin: 0;
  padding: 0;
  list-style: none;
}

.nav__link {
  display: inline-flex;
  align-items: center;
  min-height: 44px; /* comfortable touch target */
  color: var(--fg);
  text-decoration: none;
}

.nav__link:hover {
  text-decoration: underline;
  text-decoration-thickness: 2px;
}

.nav__link--active,
.nav__link[aria-current="page"] {
  font-weight: 700;
  text-decoration: underline;
}

/* --------------------------------------------------------------------------
   Hero
   -------------------------------------------------------------------------- */
.hero {
  /* horizontal padding comes from .site-header; pad vertically only so the
     title lines up with the nav above it */
  padding: var(--space-6) 0 var(--space-4);
}

.hero__title {
  margin: 0 0 var(--space-1);
  font-size: var(--text-hero);
  letter-spacing: -0.02em; /* tight tracking on large display text only */
}

.hero__tagline {
  margin: 0;
  font-size: var(--text-lg);
  color: var(--muted);
}

/* --------------------------------------------------------------------------
   Main + Section
   -------------------------------------------------------------------------- */
main {
  padding: var(--space-2) var(--space-3) var(--space-6);
}

section {
  padding: var(--space-3) 0;
  border-top: 1px solid var(--border); /* hairline divider, not a box */
}

/* --------------------------------------------------------------------------
   Button
   -------------------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: var(--space-1) var(--space-3);
  font: inherit;
  color: var(--bg);
  background: var(--fg);
  border: 1px solid var(--fg);
  border-radius: var(--radius);
  text-decoration: none;
  cursor: pointer;
  transition: opacity 150ms ease, background 150ms ease, color 150ms ease;
}

.btn:hover {
  opacity: 0.85;
}

.btn--outline {
  color: var(--fg);
  background: transparent;
}

.btn--outline:hover {
  color: var(--bg);
  background: var(--fg);
  opacity: 1;
}

/* --------------------------------------------------------------------------
   Card
   -------------------------------------------------------------------------- */
.card {
  padding: var(--space-3);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.card__title {
  margin: 0 0 var(--space-1);
  font-size: var(--text-lg);
}

.card__body {
  margin: 0 0 var(--space-3);
}

.card__body:last-child {
  margin-bottom: 0;
}

/* Responsive card grid — one column on mobile, two once there's room */
.cards {
  display: grid;
  gap: var(--space-3);
}

@media (min-width: 40rem) {
  .cards {
    grid-template-columns: repeat(2, 1fr);
  }
}

/* --------------------------------------------------------------------------
   Tag / badge
   -------------------------------------------------------------------------- */
.tag {
  display: inline-block;
  padding: 0.15rem var(--space-1);
  font-size: var(--text-sm);
  color: var(--muted);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
}

.tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1);
  margin: 0;
  padding: 0;
  list-style: none;
}

/* --------------------------------------------------------------------------
   Form
   -------------------------------------------------------------------------- */
.form__field {
  margin-bottom: var(--space-3);
}

.form__label {
  display: block;
  margin-bottom: var(--space-1);
  font-weight: 700;
}

.form__input {
  display: block;
  width: 100%;
  min-height: 44px;
  padding: var(--space-1) var(--space-2);
  font: inherit;
  color: var(--fg);
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
}

textarea.form__input {
  min-height: 8rem;
  resize: vertical;
}

.form__help {
  margin: var(--space-1) 0 0;
  font-size: var(--text-sm);
  color: var(--muted);
}

/* Errors are conveyed as text + weight, never color alone (no accent to lean on) */
.form__error {
  margin: var(--space-1) 0 0;
  font-size: var(--text-sm);
  font-weight: 700;
}

/* --------------------------------------------------------------------------
   Post layout
   -------------------------------------------------------------------------- */
.post__header {
  margin-bottom: var(--space-4);
}

.post__title {
  margin: 0 0 var(--space-2);
  font-size: var(--text-hero);
  letter-spacing: -0.02em;
}

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

/* Prose rhythm inside the article body */
.post__body > * + * {
  margin-top: var(--space-3);
}

.post__body h2 {
  margin-top: var(--space-4);
}

.post__body ul,
.post__body ol {
  padding-left: var(--space-3);
}

.post__body li + li {
  margin-top: var(--space-1);
}

.post__body blockquote {
  margin: 0;
  padding-left: var(--space-3);
  border-left: 2px solid var(--border);
  color: var(--muted);
}

.post__body figure {
  margin: 0;
}

.post__body img {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius);
}

.post__body figcaption {
  margin-top: var(--space-1);
  font-size: var(--text-sm);
  color: var(--muted);
}

/* --------------------------------------------------------------------------
   Footer
   -------------------------------------------------------------------------- */
.site-footer {
  padding: var(--space-4) var(--space-3) var(--space-6);
  color: var(--muted);
  font-size: var(--text-sm);
  border-top: 1px solid var(--border);
}

/* --------------------------------------------------------------------------
   Motion — respect reduced-motion
   -------------------------------------------------------------------------- */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
  }
}