/* felixgeelhaar.com — site-local CSS. Brand tokens carry the weight;
   this file only adds layout glue specific to the site frame. Keep small.

   Token names (from brand/tokens.css v0):
     --color-bg, --color-bg-elevated, --color-bg-muted, --color-bg-inverse
     --color-fg, --color-fg-muted, --color-fg-subtle, --color-fg-inverse
     --font-sans, --font-mono
     --ink-100..1000 (raw neutral ramp)
     --blue-500, --blue-400, ... (raw accent ramp)
*/

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: var(--font-sans, system-ui, sans-serif);
  background: var(--color-bg, #FAFAFA);
  color: var(--color-fg, #0A0A0A);
  line-height: 1.55;
  font-size: 18px;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--color-fg, #0A0A0A);
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}
a:hover { color: var(--blue-500, #0050F5); }

/* --- skip link (a11y) --- */
.skip-link {
  position: absolute; left: -9999px; top: auto;
  background: var(--color-fg, #0A0A0A);
  color: var(--color-bg, #FAFAFA);
  padding: 0.5rem 0.75rem; z-index: 999;
}
.skip-link:focus { left: 1rem; top: 1rem; }

/* --- site header --- */
.site-header {
  max-width: 64rem; margin: 0 auto;
  padding: 1.5rem;
  display: flex; align-items: baseline; justify-content: space-between;
  gap: 1.5rem; flex-wrap: wrap;
  border-bottom: 1px solid var(--ink-200, #E5E5E5);
}
.wordmark {
  display: inline-flex;
  align-items: center;
  text-decoration: none;
  color: var(--color-fg, #0A0A0A);
}
.wordmark-logotype { display: block; }
.site-header nav ul {
  list-style: none; padding: 0; margin: 0;
  display: flex; gap: 1.25rem; flex-wrap: wrap;
}
.site-header nav a {
  text-decoration: none;
  font-size: 0.95rem;
  color: var(--color-fg-muted, #525252);
}
.site-header nav a:hover { color: var(--color-fg, #0A0A0A); }
.site-header nav a[aria-current="page"] {
  color: var(--color-fg, #0A0A0A); font-weight: 600;
  border-bottom: 2px solid var(--color-fg, #0A0A0A);
  padding-bottom: 2px;
}

/* --- page frame --- */
main { max-width: 64rem; margin: 0 auto; padding: 0 1.5rem; }

.page-header {
  padding: 3rem 0 2rem;
  border-bottom: 1px solid var(--ink-200, #E5E5E5);
  margin-bottom: 2.5rem;
}
.page-header h1 {
  font-size: clamp(2rem, 5vw, 3.25rem);
  line-height: 1.1;
  margin: 0 0 1rem;
  letter-spacing: -0.01em;
  font-weight: 700;
}
.page-header .lede {
  font-size: 1.15rem;
  color: var(--color-fg-muted, #525252);
  max-width: 48rem;
  margin: 0;
}

/* --- mermaid diagrams (writing) --- */
.prose .mermaid {
  display: block;
  margin: 1.5rem 0;
  padding: 1rem;
  border: 1px solid var(--ink-200, #E5E5E5);
  background: var(--color-bg-elevated, #FFFFFF);
  font-family: var(--font-mono, ui-monospace, monospace);
  font-size: 0.85rem;
  color: var(--color-fg-muted, #525252);
  white-space: pre;
  overflow-x: auto;
}
.prose .mermaid svg {
  display: block;
  max-width: 100%;
  height: auto;
}

/* --- post hero (writing) --- */
.post-hero {
  display: block;
  margin: 1.5rem 0 2.5rem;
  border: 1px solid var(--ink-200, #E5E5E5);
  background: var(--color-bg-elevated, #FFFFFF);
}
.post-hero img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
}

/* --- prose --- */
.prose { max-width: 42rem; }
.prose h2 { font-size: 1.5rem; margin-top: 2.5rem; line-height: 1.2; }
.prose h3 { font-size: 1.15rem; margin-top: 2rem; }
.prose p  { margin: 1rem 0; }
.prose ul { padding-left: 1.25rem; margin: 1rem 0; }
.prose li + li { margin-top: 0.4rem; }

/* --- entry listing (writing, lab, talks) --- */
.entry-list { list-style: none; padding: 0; margin: 0; }
.entry {
  padding: 1.5rem 0;
  border-bottom: 1px solid var(--ink-200, #E5E5E5);
}
.entry h2 {
  margin: 0 0 0.35rem;
  font-size: 1.4rem; line-height: 1.25;
}
.entry h2 a { text-decoration: none; }
.entry h2 a:hover { text-decoration: underline; }
.entry-meta {
  display: flex; gap: 0.75rem; flex-wrap: wrap;
  font-size: 0.825rem; color: var(--color-fg-muted, #525252);
  font-family: var(--font-mono, ui-monospace, monospace);
  text-transform: uppercase; letter-spacing: 0.04em;
  margin-bottom: 0.5rem;
}
.entry-summary {
  color: var(--color-fg-muted, #525252);
  margin: 0.5rem 0 0;
}

/* --- tag chip --- */
.tag {
  display: inline-block;
  font-family: var(--font-mono, ui-monospace, monospace);
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  padding: 0.18rem 0.5rem;
  border: 1px solid var(--ink-200, #E5E5E5);
  border-radius: 999px;
  color: var(--color-fg-muted, #525252);
}

/* --- contact / work CTAs --- */
.cta-grid {
  display: grid;
  gap: 1rem;
  grid-template-columns: repeat(auto-fit, minmax(16rem, 1fr));
  margin: 2rem 0;
}
.cta {
  display: block;
  padding: 1.5rem;
  border: 1px solid var(--ink-200, #E5E5E5);
  border-radius: 0.5rem;
  text-decoration: none;
  transition: border-color 0.15s, background 0.15s;
}
.cta:hover {
  border-color: var(--color-fg, #0A0A0A);
  background: var(--color-bg-elevated, #FFFFFF);
}
.cta h3 { margin: 0 0 0.3rem; font-size: 1.05rem; }
.cta p  { margin: 0; color: var(--color-fg-muted, #525252); font-size: 0.9rem; }

/* --- footer --- */
.site-footer {
  max-width: 64rem;
  margin: 4rem auto 2rem;
  padding: 1.5rem;
  border-top: 1px solid var(--ink-200, #E5E5E5);
  font-size: 0.875rem;
  color: var(--color-fg-muted, #525252);
}
.site-footer p { margin: 0.25rem 0; }
.site-footer .muted { color: var(--color-fg-subtle, #A3A3A3); }
.site-footer__signup { margin: 0 0 1.5rem; max-width: 32rem; }

/* --- responsive --- */
@media (max-width: 600px) {
  .site-header { padding: 1rem; }
  .page-header { padding: 2rem 0 1.5rem; margin-bottom: 1.5rem; }
}