/* ===========================================================
   Between the Layers — design tokens
   Source: Claude design-canvas export, imported 2026-08-17
   =========================================================== */

:root {
  --bg: #100F0E;
  --panel: #181614;
  --panel2: #1E1B18;
  --text: #EBE6DD;
  --muted: #A09A90;
  --border: rgba(255,255,255,.10);
  --accent: #E8483F;   /* red   */
  --accent2: #2FBFA8;  /* teal  */
  --accent3: #F2A83B;  /* amber */
  --code-bg: #08090B;
  --code-text: #D7D9DE;
  --rule: rgba(255,255,255,.07);

  --tag-bronze: #C08A2E;
  --tag-silver: #9AA5B1;
  --tag-gold: #D4AF37;
  --tag-reflectie: var(--accent);
}

html[data-theme="light"] {
  --bg: #F5F0E6;
  --panel: #FFFDF8;
  --panel2: #FAF6EC;
  --text: #191612;
  --muted: #635C52;
  --border: rgba(0,0,0,.11);
  --accent: #C63A31;
  --accent2: #12756A;
  --accent3: #B87716;
  --code-bg: #0B0D10;
  --code-text: #D7D9DE;
  --rule: rgba(0,0,0,.08);
}

html, body { margin: 0; padding: 0; background: var(--bg); }
* { box-sizing: border-box; }
body {
  font-family: 'IBM Plex Sans', system-ui, sans-serif;
  color: var(--text);
  -webkit-font-smoothing: antialiased;
}
a { color: var(--accent); text-decoration: none; border-bottom: 1px solid color-mix(in oklch, var(--accent) 40%, transparent); }
a:hover { color: var(--accent2); border-bottom-color: var(--accent2); }
::selection { background: var(--accent); color: #fff; }

.mono { font-family: 'IBM Plex Mono', monospace; }

/* ---------- progress bar ---------- */
#btl-progress-track { position: fixed; top: 0; left: 0; right: 0; height: 3px; background: transparent; z-index: 60; }
#btl-progress-bar { height: 100%; width: 0%; background: linear-gradient(90deg, var(--accent), var(--accent2)); transition: width .1s linear; }

/* ---------- header ---------- */
header.btl-header {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in oklch, var(--bg) 88%, transparent);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--rule);
}
.btl-header-inner {
  max-width: 1180px; margin: 0 auto; padding: 14px clamp(18px,4vw,32px);
  display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 14px 24px;
}
.btl-logo { display: flex; align-items: baseline; gap: 10px; cursor: pointer; }
.btl-logo-mark {
  width: 30px; height: 30px; border-radius: 999px; overflow: hidden; flex: none;
  display: flex; flex-direction: column; align-self: center;
  box-shadow: 0 0 0 1px var(--border);
}
.btl-logo-mark span { flex: 1; }
.btl-logo-mark span.sep { flex: none; height: 3px; background: var(--bg); }
.btl-logo-title {
  display: block; font-family: 'Instrument Serif', serif; font-size: 24px;
  line-height: 1; letter-spacing: -.02em; align-self: center;
}
.btl-header-right { display: flex; align-items: center; gap: 20px; }
.btl-kicker {
  font-family: 'IBM Plex Mono', monospace; font-size: 11px; letter-spacing: .14em;
  text-transform: uppercase; color: var(--muted);
}
.btl-theme-toggle {
  font-family: 'IBM Plex Mono', monospace; font-size: 11px; letter-spacing: .12em;
  text-transform: uppercase; color: var(--muted); background: var(--panel);
  border: 1px solid var(--border); border-radius: 999px; padding: 7px 14px; cursor: pointer;
}
.btl-theme-toggle:hover { color: var(--text); border-color: var(--accent); }

main.btl-main { max-width: 1180px; margin: 0 auto; padding: 0 clamp(18px,4vw,32px) 100px; }
main.btl-main.is-post { padding-bottom: 120px; }

/* ---------- index / hero ---------- */
.btl-hero {
  padding: clamp(48px,9vw,96px) 0 clamp(40px,7vw,72px); border-bottom: 1px solid var(--rule);
}
.btl-hero > div { max-width: 820px; }
.btl-hero-kicker {
  font-family: 'IBM Plex Mono', monospace; font-size: 11px; letter-spacing: .18em;
  text-transform: uppercase; color: var(--accent2); margin: 0 0 22px;
}
.btl-hero h1 {
  font-family: 'Instrument Serif', serif; font-size: clamp(40px,7.4vw,76px); line-height: 1.03;
  letter-spacing: -.025em; margin: 0 0 24px; font-weight: 400;
}
.btl-hero h1 .accent { color: var(--accent); }
.btl-hero p { font-size: clamp(17px,2vw,19px); line-height: 1.6; color: var(--muted); max-width: 52ch; margin: 0; text-wrap: pretty; }

/* ---------- cards ---------- */
.btl-latest-card {
  cursor: pointer; display: flex; flex-direction: column; gap: 22px;
  padding: clamp(24px,4vw,40px); background: var(--panel); border: 1px solid var(--border); border-radius: 4px;
  margin-top: 56px;
}
.btl-latest-card:hover { border-color: var(--accent); }
.btl-latest-meta { display: flex; flex-wrap: wrap; align-items: center; gap: 10px 18px; }
.btl-eyebrow { font-family: 'IBM Plex Mono', monospace; font-size: 11px; letter-spacing: .16em; text-transform: uppercase; color: var(--accent2); }
.btl-date { font-family: 'IBM Plex Mono', monospace; font-size: 12px; color: var(--muted); }
.btl-tag {
  display: inline-block; width: fit-content; font-family: 'IBM Plex Mono', monospace; font-size: 10px;
  letter-spacing: .12em; text-transform: uppercase; border-radius: 999px; padding: 5px 10px;
  border: 1px solid var(--border); color: var(--text);
}
.btl-tag[data-tag="bronze"] { color: var(--tag-bronze); border-color: color-mix(in oklch, var(--tag-bronze) 55%, transparent); }
.btl-tag[data-tag="silver"] { color: var(--tag-silver); border-color: color-mix(in oklch, var(--tag-silver) 55%, transparent); }
.btl-tag[data-tag="gold"]   { color: var(--tag-gold);   border-color: color-mix(in oklch, var(--tag-gold) 55%, transparent); }
.btl-tag[data-tag="reflectie"] { color: var(--tag-reflectie); border-style: dashed; font-style: italic; }

.btl-latest-card h2 {
  font-family: 'Instrument Serif', serif; font-size: clamp(28px,4.4vw,44px); line-height: 1.12;
  letter-spacing: -.02em; margin: 0 0 18px; font-weight: 400;
}
.btl-latest-card p {
  font-size: 17px; line-height: 1.65; color: var(--muted); margin: 0 0 24px; max-width: 64ch; text-wrap: pretty;
}
.btl-readmore { font-family: 'IBM Plex Mono', monospace; font-size: 12px; letter-spacing: .1em; text-transform: uppercase; color: var(--accent); }

.btl-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(min(100%,280px), 1fr)); gap: 24px; margin-top: 24px;
}
.btl-card {
  cursor: pointer; padding: 32px; border: 1px solid var(--rule); border-radius: 4px; background: var(--panel2);
}
.btl-card:hover { border-color: var(--accent); }
.btl-card .btl-eyebrow-muted {
  font-family: 'IBM Plex Mono', monospace; font-size: 11px; letter-spacing: .14em;
  text-transform: uppercase; color: var(--muted);
}
.btl-card h3 {
  font-family: 'Instrument Serif', serif; font-size: 28px; line-height: 1.15; margin: 14px 0 12px; font-weight: 400;
}
.btl-card p { font-size: 15px; line-height: 1.6; color: var(--muted); margin: 0; }

/* ---------- post view ---------- */
.btl-back {
  cursor: pointer; font-family: 'IBM Plex Mono', monospace; font-size: 11px; letter-spacing: .14em;
  text-transform: uppercase; color: var(--muted); display: inline-block; padding: 72px 0 0;
}
.btl-article-grid {
  display: flex; flex-wrap: wrap; gap: 48px; align-items: flex-start; padding-top: 40px;
}
@media (max-width: 900px) {
  .btl-toc { display: none; }
}
.btl-article { flex: 1 1 440px; max-width: 680px; min-width: 0; }
.btl-article-kicker { font-family: 'IBM Plex Mono', monospace; font-size: 11px; letter-spacing: .18em; text-transform: uppercase; color: var(--accent2); margin: 0 0 22px; }
.btl-article h1 { font-family: 'Instrument Serif', serif; font-size: clamp(34px,6vw,60px); line-height: 1.05; letter-spacing: -.025em; margin: 0 0 26px; font-weight: 400; }
.btl-article-dek { font-size: clamp(18px,2.3vw,21px); line-height: 1.55; color: var(--muted); margin: 0 0 40px; text-wrap: pretty; }
.btl-byline { display: flex; align-items: center; gap: 16px; padding: 20px 0; border-top: 1px solid var(--rule); border-bottom: 1px solid var(--rule); margin-bottom: 56px; }
.btl-avatar { width: 44px; height: 44px; border-radius: 999px; background: linear-gradient(140deg, var(--accent), var(--accent2)); flex: none; }
.btl-byline-name { font-size: 15px; font-weight: 600; }
.btl-byline-meta { font-family: 'IBM Plex Mono', monospace; font-size: 12px; color: var(--muted); }

.btl-article h2 { font-family: 'Instrument Serif', serif; font-size: clamp(26px,3.4vw,34px); line-height: 1.22; letter-spacing: -.02em; margin: 48px 0 20px; font-weight: 400; scroll-margin-top: 90px; }
.btl-article h2:first-of-type { margin-top: 0; }
.btl-article p { font-size: 18px; line-height: 1.75; margin: 0 0 22px; text-wrap: pretty; }
.btl-article blockquote {
  margin: 0 0 34px; padding: 22px 26px; border-left: 3px solid var(--accent);
  background: var(--panel2); font-style: italic; font-size: 19px; line-height: 1.6; color: var(--text);
}

.btl-code-block { background: var(--code-bg); border: 1px solid rgba(255,255,255,.08); border-radius: 4px; padding: 22px 24px; margin: 0 0 34px; overflow-x: auto; }
.btl-code-caption { font-family: 'IBM Plex Mono', monospace; font-size: 10px; letter-spacing: .14em; text-transform: uppercase; color: var(--muted); margin-bottom: 14px; }
.btl-code-block pre { margin: 0; font-family: 'IBM Plex Mono', monospace; font-size: 13.5px; line-height: 1.75; color: var(--code-text); white-space: pre; }

.btl-mermaid { background: var(--panel2); border: 1px solid var(--rule); border-radius: 4px; padding: 28px; margin: 0 0 34px; overflow-x: auto; }

.btl-takeaways { border: 1px solid var(--accent); border-radius: 4px; padding: 34px; background: color-mix(in oklch, var(--accent) 8%, transparent); margin: 40px 0; }
.btl-takeaways-title { font-family: 'IBM Plex Mono', monospace; font-size: 10px; letter-spacing: .16em; text-transform: uppercase; color: var(--accent); margin-bottom: 22px; }
.btl-takeaways-list { display: flex; flex-direction: column; gap: 18px; }
.btl-takeaway { display: grid; grid-template-columns: 28px 1fr; gap: 14px; align-items: start; }
.btl-takeaway-num { font-family: 'IBM Plex Mono', monospace; font-size: 13px; color: var(--muted); }
.btl-takeaway-text { font-size: 17px; line-height: 1.6; }

.btl-article-footer { display: flex; align-items: center; gap: 18px; margin-top: 56px; padding-top: 32px; border-top: 1px solid var(--rule); }
.btl-article-footer-bio { font-size: 14px; line-height: 1.55; color: var(--muted); max-width: 56ch; }

.btl-toc { flex: 0 1 200px; min-width: 170px; position: sticky; top: 104px; }
.btl-toc-title { font-family: 'IBM Plex Mono', monospace; font-size: 10px; letter-spacing: .16em; text-transform: uppercase; color: var(--muted); margin-bottom: 18px; }
.btl-toc nav { display: flex; flex-direction: column; gap: 12px; border-left: 1px solid var(--rule); padding-left: 18px; }
.btl-toc nav a { font-size: 14px; line-height: 1.45; color: var(--muted); border: none; }
.btl-toc nav a:hover { color: var(--accent); }

/* ---------- footer ---------- */
footer.btl-footer { border-top: 1px solid var(--rule); padding: 28px clamp(18px,4vw,32px); }
.btl-footer-inner {
  max-width: 1180px; margin: 0 auto; display: flex; flex-wrap: wrap; gap: 8px 20px; justify-content: space-between;
  font-family: 'IBM Plex Mono', monospace; font-size: 11px; letter-spacing: .1em; text-transform: uppercase; color: var(--muted);
}