/* ═══════════════════════════════════════════════════════════════
   Ascendion Engineering — Design System v4
   Changes from v3:
   1. Single --max shell — hero + content share same left edge
   2. Grid ghost boxes removed — cards own their borders
   3. Diagrams — Figma/Gliffy light theme, centered, no dead space
   4. Section hero — expanded two-column SVG illustration
   5. Footer text — full white, fully readable
   6. Base font size raised to 18px across all content
   ═══════════════════════════════════════════════════════════════ */

@import url('https://fonts.googleapis.com/css2?family=IBM+Plex+Sans:ital,wght@0,300;0,400;0,500;0,600;1,400&family=IBM+Plex+Mono:wght@400;500&display=swap');

/* ── TOKENS ── */
:root {
  --bg:           #FFFFFF;
  --bg-subtle:    #F9F8F6;
  --ink:          #0E0E0E;
  --ink-2:        #3C3C3C;
  --ink-3:        #6E6E6E;
  --ink-4:        #B0B0AA;
  --border:       #E8E8E4;
  --border-md:    #C4C4BE;
  --accent:       #C96330;
  --nav-bg:       #0E0E0E;
  --nav-text:     rgba(255,255,255,0.58);
  --nav-hover:    #FFFFFF;
  --nav-border:   rgba(255,255,255,0.07);
  --font:         'IBM Plex Sans', -apple-system, BlinkMacSystemFont, sans-serif;
  --mono:         'IBM Plex Mono', 'Courier New', monospace;
  --r:            6px;
  --r-lg:         10px;
  --max:          1140px;   /* ONE width used everywhere */
  --prose:        760px;    /* article reading column */
  --t:            0.18s ease;

  /* Diagram light-theme — Figma/Gliffy palette */
  --dg-bg:        #F4F7FB;
  --dg-border:    #D8E2F0;
  --dg-node:      #FFFFFF;
  --dg-stroke:    #4A72A8;
  --dg-text:      #1A2840;
  --dg-line:      #7AAAD8;
  --dg-accent:    #C96330;
}

/* ── RESET ── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font);
  font-size: 18px;                 /* FIX 6: raised from 17px */
  background: var(--bg);
  color: var(--ink);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ── WORDMARK ANIMATION ── */
@keyframes wm-char {
  from { opacity: 0; transform: translateY(4px); }
  to   { opacity: 1; transform: translateY(0); }
}
.wm-char { display: inline-block; animation: wm-char 0.4s ease both; }

/* ── NAV ── */
.nav {
  position: sticky; top: 0; z-index: 100;
  background: var(--nav-bg); border-bottom: 1px solid var(--nav-border);
  height: 58px; display: flex; align-items: center; padding: 0 2.5rem;
}
.nav-wordmark {
  font-size: 1rem; font-weight: 600; color: #FFFFFF;
  text-decoration: none; letter-spacing: 0.01em; flex-shrink: 0;
  font-family: var(--font); display: flex; align-items: center; gap: 0.5rem;
}
.nav-sep { width: 1px; height: 18px; background: rgba(255,255,255,0.1); margin: 0 1.5rem; }
.nav-links { display: flex; align-items: center; flex: 1; overflow: hidden; }
.nav-links a {
  font-size: 0.88rem; font-weight: 400; color: var(--nav-text);
  text-decoration: none; padding: 0.32rem 0.7rem; border-radius: var(--r);
  transition: color var(--t); white-space: nowrap;
}
.nav-links a:hover { color: var(--nav-hover); }
.nav-links a.active { color: #FFFFFF; font-weight: 500; }
.nav-cta {
  margin-left: auto; flex-shrink: 0; font-size: 0.84rem; font-weight: 500;
  color: var(--ink); background: #FFFFFF; padding: 0.38rem 1.1rem;
  border-radius: 99px; text-decoration: none; transition: opacity var(--t); font-family: var(--font);
}
.nav-cta:hover { opacity: 0.8; }

/* ── SHELL ────────────────────────────────────────────────────────
   FIX 1: every element on every page uses this one container.
   Hero left edge = filter bar left edge = content left edge.
   ─────────────────────────────────────────────────────────────── */
.shell {
  max-width: var(--max);
  margin: 0 auto;
  padding-left: 2.5rem;
  padding-right: 2.5rem;
}

/* ── BREADCRUMB ── */
.breadcrumb {
  display: flex; align-items: center; gap: 0.45rem;
  font-size: 0.84rem; color: var(--ink-3);
  margin-bottom: 1.25rem; font-family: var(--mono);
}
.breadcrumb a { color: var(--ink-3); text-decoration: none; transition: color var(--t); }
.breadcrumb a:hover { color: var(--ink); }
.breadcrumb .sep { color: var(--ink-4); }
.breadcrumb .curr { color: var(--ink-2); }

/* ── HERO: LANDING ── */
.hero { border-bottom: 1px solid var(--border); padding: 4.5rem 0 4rem; }
.hero-label {
  font-family: var(--mono); font-size: 0.78rem; font-weight: 500;
  letter-spacing: 0.1em; text-transform: uppercase;
  color: var(--accent); margin-bottom: 1rem;
}
.hero h1 {
  font-size: clamp(2.2rem, 4vw, 3.2rem); font-weight: 300;
  letter-spacing: -0.025em; color: var(--ink); line-height: 1.12; margin-bottom: 1.1rem;
}
.hero h1 strong { font-weight: 600; }
.hero-desc { font-size: 1.1rem; color: var(--ink-2); line-height: 1.72; max-width: 600px; }

/* ── HERO: SECTION ────────────────────────────────────────────────
   FIX 4: two-column layout — text left, expanded SVG art right.
   SVG is 3× the card size, vertically centered on the title.
   ─────────────────────────────────────────────────────────────── */
.hero-section { border-bottom: 1px solid var(--border); padding: 4.5rem 0 4rem; }
.hero-section-inner {
  display: flex; align-items: center; gap: 4rem;
}
.hero-section-text { flex: 1; min-width: 0; }
.hero-section-art {
  flex-shrink: 0; width: 240px; height: 180px;
  display: flex; align-items: center; justify-content: center;
}
.hero-section-art svg { width: 100%; height: 100%; overflow: visible; }

/* ── HERO: ARTICLE ── */
.hero-article { border-bottom: 1px solid var(--border); padding: 4rem 0 3.5rem; }
.hero-article h1 {
  font-size: clamp(1.8rem, 3vw, 2.5rem); font-weight: 500;
  letter-spacing: -0.02em; color: var(--ink); line-height: 1.2; margin-bottom: 0.75rem;
}
.hero-desc { font-size: 1.1rem; color: var(--ink-2); line-height: 1.72; max-width: 600px; }
.hero-tags { display: flex; flex-wrap: wrap; gap: 0.4rem; margin-top: 1.5rem; }
.hero-tag {
  font-family: var(--mono); font-size: 0.74rem;
  padding: 0.24rem 0.7rem; border: 1px solid var(--border-md);
  border-radius: 99px; color: var(--ink-3);
}

/* ── FILTER BAR ── */
.filter-bar { border-bottom: 1px solid var(--border); overflow-x: auto; scrollbar-width: none; }
.filter-bar::-webkit-scrollbar { display: none; }
.filter-bar .shell { display: flex; align-items: stretch; white-space: nowrap; padding-top: 0; padding-bottom: 0; }
.filter-tag {
  font-size: 0.86rem; color: var(--ink-3); padding: 0.9rem 0.85rem;
  border: none; background: none; cursor: pointer; font-family: var(--font);
  text-decoration: none; border-bottom: 2px solid transparent; display: inline-block;
  transition: color var(--t), border-color var(--t);
}
.filter-tag:hover { color: var(--ink); }
.filter-tag.active { color: var(--accent); border-bottom-color: var(--accent); font-weight: 500; }

/* ── STATS ROW ── */
.stats-row {
  padding-top: 2.5rem; padding-bottom: 2rem;
  display: flex; gap: 4rem; border-bottom: 1px solid var(--border);
}
.stat-n { font-size: 2.2rem; font-weight: 300; color: var(--ink); letter-spacing: -0.04em; line-height: 1; }
.stat-l { font-size: 0.78rem; color: var(--ink-3); margin-top: 0.3rem; font-family: var(--mono); text-transform: uppercase; letter-spacing: 0.07em; }

/* ── GROUP LABEL ── */
.group-section { padding-top: 2.5rem; }
.group-section:last-of-type { padding-bottom: 5rem; }
.group-label {
  font-family: var(--mono); font-size: 0.74rem; font-weight: 500;
  letter-spacing: 0.12em; text-transform: uppercase; color: var(--ink-3);
  margin-bottom: 1rem; padding-bottom: 0.65rem; border-bottom: 1px solid var(--border);
  display: flex; align-items: baseline; justify-content: space-between;
}
.group-label-desc {
  color: var(--ink-4); font-weight: 400; letter-spacing: 0;
  text-transform: none; font-size: 0.84rem; font-family: var(--font);
}

/* ── SECTION CARD GRID ────────────────────────────────────────────
   FIX 2: no background on grid container — cards own every border.
   Empty grid cells = transparent. Zero ghost boxes.
   ─────────────────────────────────────────────────────────────── */
.section-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  /* outer border on container top + left only */
  border-top: 1px solid var(--border);
  border-left: 1px solid var(--border);
  border-radius: var(--r-lg);
  overflow: hidden;
  margin-bottom: 2.5rem;
  background: transparent;  /* NO background — kills ghost boxes */
}
.section-card {
  background: var(--bg); display: block; text-decoration: none;
  padding: 1.75rem 1.75rem 1.5rem; position: relative; overflow: hidden;
  /* Each card closes its own right + bottom edge */
  border-right: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  transition: background var(--t);
}
.section-card:hover { background: var(--bg-subtle); }
.section-card:hover .sc-arrow { opacity: 1; transform: translateX(0); }

.sc-illustration {
  position: absolute; top: 1.25rem; right: 1.25rem;
  width: 82px; height: 58px; opacity: 0.68; pointer-events: none;
}
.sc-path { font-family: var(--mono); font-size: 0.74rem; color: var(--accent); letter-spacing: 0.02em; margin-bottom: 0.5rem; }
.sc-title { font-size: 1.02rem; font-weight: 600; color: var(--ink); line-height: 1.35; margin-bottom: 0.45rem; padding-right: 92px; }
.sc-desc { font-size: 0.88rem; color: var(--ink-3); line-height: 1.62; margin-bottom: 1rem; }
.sc-footer { display: flex; align-items: center; justify-content: flex-end; }
.sc-arrow { font-size: 0.9rem; color: var(--accent); opacity: 0; transform: translateX(-5px); transition: opacity var(--t), transform var(--t); }

/* ── ARTICLE LIST ── */
.article-list { padding-top: 2.5rem; padding-bottom: 5rem; }
.list-label {
  font-family: var(--mono); font-size: 0.74rem; letter-spacing: 0.1em;
  text-transform: uppercase; color: var(--ink-3);
  padding-bottom: 0.75rem; border-bottom: 1px solid var(--border);
}
.article-row {
  display: grid; grid-template-columns: 1fr 1.5rem;
  align-items: center; gap: 1rem;
  padding: 1.6rem 0; border-bottom: 1px solid var(--border);
  text-decoration: none; max-width: var(--prose);
}
.article-row:hover .ar-arrow { opacity: 1; transform: translateX(0); }
.ar-label { font-family: var(--mono); font-size: 0.73rem; color: var(--accent); margin-bottom: 0.3rem; }
.ar-title { font-size: 1.08rem; font-weight: 600; color: var(--ink); margin-bottom: 0.3rem; line-height: 1.3; }
.ar-desc { font-size: 0.9rem; color: var(--ink-3); line-height: 1.6; }
.ar-arrow { font-size: 1rem; color: var(--accent); opacity: 0; transform: translateX(-4px); transition: opacity var(--t), transform var(--t); align-self: center; }

/* ── ARTICLE BODY ── */
.article-body { max-width: var(--prose); padding-top: 3rem; padding-bottom: 3rem; }
.article-body h2 { font-size: 1.35rem; font-weight: 600; color: var(--ink); margin: 2.75rem 0 0.75rem; padding-bottom: 0.5rem; border-bottom: 1px solid var(--border); }
.article-body h3 { font-size: 1.1rem; font-weight: 600; color: var(--ink); margin: 2rem 0 0.55rem; }
.article-body h4 { font-family: var(--mono); font-size: 0.78rem; font-weight: 500; color: var(--ink-3); text-transform: uppercase; letter-spacing: 0.08em; margin: 1.5rem 0 0.4rem; }
.article-body p { font-size: 1rem; color: var(--ink-2); line-height: 1.82; margin-bottom: 1.2rem; }
.article-body p:first-of-type { color: var(--ink); font-size: 1.05rem; }
.article-body a { color: var(--accent); text-underline-offset: 3px; }
.article-body a:hover { opacity: 0.75; }
.article-body ul, .article-body ol { margin: 0 0 1.1rem 1.5rem; }
.article-body li { font-size: 0.98rem; color: var(--ink-2); line-height: 1.78; margin-bottom: 0.4rem; }
.article-body code { font-family: var(--mono); font-size: 0.84em; background: var(--bg-subtle); padding: 0.12em 0.42em; border-radius: 3px; color: var(--ink); border: 1px solid var(--border); }
.article-body pre { background: var(--bg-subtle); border-radius: var(--r-lg); padding: 1.5rem; overflow-x: auto; margin: 1.5rem 0; border: 1px solid var(--border); }
.article-body pre code { background: none; border: none; padding: 0; font-size: 0.86rem; color: var(--ink); line-height: 1.65; }
.article-body blockquote { border-left: 2px solid var(--border-md); margin: 1.5rem 0; padding: 0.7rem 1.2rem; background: var(--bg-subtle); border-radius: 0 var(--r) var(--r) 0; }
.article-body blockquote p { margin: 0; font-size: 0.94rem; color: var(--ink-3); }
.article-body blockquote strong { color: var(--ink-2); }
.article-body table { width: 100%; border-collapse: collapse; margin: 1.5rem 0; font-size: 0.9rem; border: 1px solid var(--border); border-radius: var(--r); overflow: hidden; }
.article-body th { background: var(--bg-subtle); color: var(--ink); font-weight: 600; font-size: 0.79rem; letter-spacing: 0.04em; text-transform: uppercase; padding: 0.75rem 1rem; text-align: left; border-bottom: 1px solid var(--border-md); }
.article-body td { padding: 0.7rem 1rem; color: var(--ink-2); border-bottom: 1px solid var(--border); vertical-align: top; line-height: 1.58; }
.article-body tr:last-child td { border-bottom: none; }

/* ── DIAGRAM — LIGHT THEME ────────────────────────────────────────
   FIX 3: Figma/Gliffy aesthetic — light blue-grey canvas,
   white nodes, dark text, muted steel connectors.
   FIX 3b: flex centering removes ALL Mermaid top dead-space.
   ─────────────────────────────────────────────────────────────── */
.diagram-label {
  font-family: var(--mono); font-size: 0.74rem; font-weight: 500;
  letter-spacing: 0.1em; text-transform: uppercase; color: var(--ink-3);
  margin-bottom: 0.75rem; padding-bottom: 0.65rem; border-bottom: 1px solid var(--border);
}
.diagram-wrap {
  background: var(--dg-bg);
  border: 1px solid var(--dg-border);
  border-radius: var(--r-lg);
  padding: 2.5rem 2rem;
  margin: 0 0 2.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  min-height: 300px;
}
/* Mermaid renders into a child div — flex it to fill + center */
.diagram-wrap > div {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
}
/* Strip Mermaid's injected top margin/padding from the SVG */
.diagram-wrap svg {
  max-width: 100%;
  height: auto !important;
  margin-top: 0 !important;
  padding-top: 0 !important;
  display: block;
}

/* ── RELATED ── */
.related { max-width: var(--prose); padding-top: 1.75rem; padding-bottom: 3.5rem; border-top: 1px solid var(--border); }
.related h4 { font-family: var(--mono); font-size: 0.74rem; letter-spacing: 0.1em; text-transform: uppercase; color: var(--ink-3); margin-bottom: 0.85rem; }
.related-links { display: flex; flex-wrap: wrap; gap: 0.5rem; }
.related-link { font-family: var(--mono); font-size: 0.8rem; padding: 0.42rem 0.9rem; border: 1px solid var(--border-md); border-radius: 99px; text-decoration: none; color: var(--ink-2); transition: background var(--t), border-color var(--t), color var(--t); }
.related-link:hover { background: var(--ink); border-color: var(--ink); color: #FFF; }

/* ── FOOTER ────────────────────────────────────────────────────────
   FIX 5: all footer text is pure white — fully readable for
   engineers working in any lighting condition.
   ─────────────────────────────────────────────────────────────── */
.footer { background: var(--nav-bg); border-top: 1px solid rgba(255,255,255,0.08); padding: 2.75rem 0; }
.footer .shell { display: flex; align-items: center; justify-content: space-between; gap: 2rem; }
.footer-brand { font-size: 0.95rem; font-weight: 600; color: #FFFFFF; }
.footer-meta {
  font-family: var(--mono); font-size: 0.78rem;
  color: rgba(255,255,255,0.82);  /* FIX 5: near-white, fully legible */
  text-align: right; line-height: 1.8;
}

/* ── RESPONSIVE ── */
@media (max-width: 960px) {
  .section-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 680px) {
  body { font-size: 17px; }
  .nav { padding: 0 1.25rem; }
  .nav-links { display: none; }
  .shell { padding-left: 1.5rem; padding-right: 1.5rem; }
  .section-grid { grid-template-columns: 1fr; }
  .section-card { border-right: none; }
  .hero-section-inner { flex-direction: column; gap: 2rem; }
  .hero-section-art { width: 100%; height: 160px; }
  .sc-illustration { display: none; }
  .sc-title { padding-right: 0; }
  .footer .shell { flex-direction: column; text-align: center; }
  .footer-meta { text-align: center; }
}