/* The Three-Box Solution — threebox.donbarger.com */

:root {
  --bg: #0f172a;
  --bg-soft: #1e293b;
  --surface: #ffffff;
  --surface-soft: #f8fafc;
  --ink: #0f172a;
  --ink-soft: #475569;
  --ink-faint: #94a3b8;
  --line: #e2e8f0;
  --line-strong: #cbd5e1;

  /* Box color system */
  --framework: #6366f1;
  --box1: #2563eb;   /* Present · Preserve */
  --box2: #d97706;   /* Past · Destroy */
  --box3: #059669;   /* Future · Create */
  --integration: #0d9488;
  --leadership: #7c3aed;

  --maxw: 1120px;
  --radius: 14px;
  --shadow: 0 1px 2px rgba(15,23,42,.04), 0 8px 24px rgba(15,23,42,.06);
  --shadow-lg: 0 12px 40px rgba(15,23,42,.12);
  --font: "Source Sans 3", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --serif: "Spectral", Georgia, "Times New Roman", serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font);
  color: var(--ink);
  background: var(--surface-soft);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; }
img { max-width: 100%; }

.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }

/* ---------- Top bar ---------- */
.topbar {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255,255,255,.85);
  backdrop-filter: saturate(150%) blur(10px);
  border-bottom: 1px solid var(--line);
}
.topbar .wrap { display: flex; align-items: center; justify-content: space-between; height: 62px; }
.brand { display: flex; align-items: center; gap: 12px; text-decoration: none; font-weight: 700; letter-spacing: -.01em; }
.brand .mark {
  display: grid; grid-template-columns: 1fr 1fr; grid-template-rows: 1fr 1fr; gap: 2px;
  width: 26px; height: 26px;
}
.brand .mark span { border-radius: 3px; }
.brand .mark span:nth-child(1){ background: var(--box1); }
.brand .mark span:nth-child(2){ background: var(--box2); }
.brand .mark span:nth-child(3){ background: var(--box3); }
.brand .mark span:nth-child(4){ background: var(--framework); }
.brand b { font-size: 17px; }
.brand small { display:block; font-weight: 500; color: var(--ink-faint); font-size: 11px; letter-spacing: .02em; margin-top: -3px; }
.topbar nav a { text-decoration: none; color: var(--ink-soft); font-weight: 600; font-size: 14px; margin-left: 22px; }
.topbar nav a:hover { color: var(--ink); }
@media (max-width: 640px){ .topbar nav { display: none; } }

/* ---------- Hero ---------- */
.hero {
  background:
    radial-gradient(1200px 400px at 80% -10%, rgba(99,102,241,.25), transparent 60%),
    radial-gradient(900px 400px at 0% 0%, rgba(5,150,105,.18), transparent 55%),
    linear-gradient(180deg, #0f172a, #111c33);
  color: #e2e8f0;
  padding: 78px 0 90px;
}
.hero .eyebrow { color: #a5b4fc; font-weight: 700; letter-spacing: .14em; text-transform: uppercase; font-size: 12px; }
.hero h1 { font-family: var(--serif); font-weight: 800; font-size: clamp(34px, 6vw, 60px); line-height: 1.02; margin: 14px 0 6px; letter-spacing: -.02em; color: #fff; }
.hero .sub { font-size: clamp(17px, 2.4vw, 21px); color: #cbd5e1; max-width: 720px; }
.hero .byline { margin-top: 10px; color: var(--ink-faint); font-size: 14px; }
.hero .pull {
  margin-top: 30px; max-width: 760px; padding: 18px 22px; border-left: 3px solid #a5b4fc;
  background: rgba(255,255,255,.04); border-radius: 0 10px 10px 0; font-family: var(--serif);
  font-size: 18px; font-style: italic; color: #e9eef7;
}
.hero .pull span { display:block; margin-top: 8px; font-style: normal; font-family: var(--font); font-size: 13px; color: var(--ink-faint); }

/* ---------- Three-box visual ---------- */
.boxes { margin-top: -52px; }
.boxes .grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; }
@media (max-width: 820px){ .boxes .grid { grid-template-columns: 1fr; } }
.box {
  background: var(--surface); border-radius: var(--radius); padding: 22px 22px 24px;
  box-shadow: var(--shadow-lg); border-top: 5px solid var(--line);
}
.box.b1 { border-top-color: var(--box1); }
.box.b2 { border-top-color: var(--box2); }
.box.b3 { border-top-color: var(--box3); }
.box .tag { font-weight: 800; font-size: 12px; letter-spacing: .1em; text-transform: uppercase; }
.box.b1 .tag { color: var(--box1); }
.box.b2 .tag { color: var(--box2); }
.box.b3 .tag { color: var(--box3); }
.box h3 { margin: 6px 0 4px; font-size: 20px; letter-spacing: -.01em; }
.box .verb { font-family: var(--serif); font-style: italic; color: var(--ink-soft); margin-bottom: 8px; }
.box p { margin: 0; color: var(--ink-soft); font-size: 14.5px; }

/* ---------- Sections ---------- */
section { padding: 56px 0; }
.section-head { margin-bottom: 26px; }
.section-head h2 { font-family: var(--serif); font-size: clamp(26px, 4vw, 36px); margin: 0 0 6px; letter-spacing: -.02em; }
.section-head p { margin: 0; color: var(--ink-soft); max-width: 680px; }

/* Framework table */
.matrix { overflow-x: auto; border: 1px solid var(--line); border-radius: var(--radius); background: var(--surface); box-shadow: var(--shadow); }
table.fw { width: 100%; border-collapse: collapse; min-width: 640px; }
table.fw th, table.fw td { text-align: left; padding: 14px 16px; border-bottom: 1px solid var(--line); font-size: 14.5px; vertical-align: top; }
table.fw thead th { font-size: 12px; text-transform: uppercase; letter-spacing: .08em; color: var(--ink-faint); }
table.fw thead th.h1 { color: var(--box1); }
table.fw thead th.h2 { color: var(--box2); }
table.fw thead th.h3 { color: var(--box3); }
table.fw tbody tr:last-child td { border-bottom: none; }
table.fw td:first-child, table.fw th:first-child { font-weight: 700; color: var(--ink); background: var(--surface-soft); }

/* ---------- Article cards ---------- */
.cards { display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px; }
@media (max-width: 760px){ .cards { grid-template-columns: 1fr; } }
.card {
  display: flex; flex-direction: column; text-decoration: none; color: inherit;
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 22px; box-shadow: var(--shadow); transition: transform .15s ease, box-shadow .15s ease, border-color .15s ease;
  border-left: 4px solid var(--line-strong);
}
.card:hover { transform: translateY(-3px); box-shadow: var(--shadow-lg); }
.card .meta { display: flex; align-items: center; gap: 10px; margin-bottom: 10px; }
.badge { font-size: 11px; font-weight: 800; letter-spacing: .06em; text-transform: uppercase; padding: 4px 9px; border-radius: 999px; color: #fff; }
.card .chapter { color: var(--ink-faint); font-size: 13px; font-weight: 600; }
.card h3 { margin: 0 0 8px; font-size: 21px; letter-spacing: -.01em; font-family: var(--serif); }
.card p { margin: 0 0 16px; color: var(--ink-soft); font-size: 14.5px; }
.card .more { margin-top: auto; font-weight: 700; font-size: 14px; }
.card .more::after { content: " →"; }

/* Box color accents (shared by cards + article header) */
.k-framework { --c: var(--framework); }
.k-box1 { --c: var(--box1); }
.k-box2 { --c: var(--box2); }
.k-box3 { --c: var(--box3); }
.k-integration { --c: var(--integration); }
.k-leadership { --c: var(--leadership); }
.card[class*="k-"] { border-left-color: var(--c); }
.card[class*="k-"] .badge { background: var(--c); }
.card[class*="k-"] .more { color: var(--c); }

/* ---------- Applied callout ---------- */
.applied {
  background: linear-gradient(180deg, #0f172a, #14213d); color: #e2e8f0;
  border-radius: var(--radius); padding: 34px; box-shadow: var(--shadow-lg);
}
.applied h2 { font-family: var(--serif); color: #fff; margin: 0 0 10px; font-size: 28px; }
.applied p { color: #cbd5e1; max-width: 760px; }
.applied .pills { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 16px; }
.applied .pill { background: rgba(255,255,255,.07); border: 1px solid rgba(255,255,255,.12); border-radius: 999px; padding: 7px 14px; font-size: 13px; font-weight: 600; }

/* ---------- Article page ---------- */
.article-hero { padding: 48px 0 0; }
.article-hero .back { text-decoration: none; color: var(--ink-soft); font-weight: 600; font-size: 14px; }
.article-hero .back:hover { color: var(--ink); }
.article-hero .meta { display: flex; align-items: center; gap: 12px; margin: 22px 0 8px; }
.article-hero h1 { font-family: var(--serif); font-size: clamp(30px, 5vw, 46px); margin: 6px 0 4px; letter-spacing: -.02em; }
.article-hero .pages { color: var(--ink-faint); font-weight: 600; font-size: 14px; }
.article-rule { height: 4px; width: 64px; border-radius: 999px; background: var(--c, var(--framework)); margin: 18px 0 0; }

.prose {
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
  padding: clamp(24px, 4vw, 52px); box-shadow: var(--shadow); margin: 28px 0 60px;
  font-size: 17px;
}
.prose h1 { display: none; } /* first H1 duplicates the page title */
.prose h2 { font-family: var(--serif); font-size: 27px; margin: 38px 0 12px; padding-bottom: 8px; border-bottom: 2px solid var(--line); letter-spacing: -.01em; }
.prose h3 { font-size: 20px; margin: 26px 0 8px; }
.prose p { margin: 0 0 16px; color: #1f2937; }
.prose ul, .prose ol { padding-left: 22px; margin: 0 0 16px; }
.prose li { margin-bottom: 7px; }
.prose strong { color: var(--ink); }
.prose blockquote {
  margin: 18px 0; padding: 14px 20px; border-left: 4px solid var(--c, var(--framework));
  background: var(--surface-soft); border-radius: 0 10px 10px 0; font-family: var(--serif);
  font-style: italic; font-size: 18px; color: #334155;
}
.prose blockquote p:last-child { margin-bottom: 0; }
.prose table { width: 100%; border-collapse: collapse; margin: 18px 0; font-size: 15px; display: block; overflow-x: auto; }
.prose th, .prose td { border: 1px solid var(--line); padding: 10px 12px; text-align: left; vertical-align: top; }
.prose thead th { background: var(--surface-soft); font-size: 13px; text-transform: uppercase; letter-spacing: .04em; color: var(--ink-soft); }
.prose code { background: var(--surface-soft); padding: 2px 6px; border-radius: 6px; font-size: 14px; }
.prose hr { border: none; border-top: 1px solid var(--line); margin: 32px 0; }
.prose a { color: var(--box1); }

/* article nav */
.article-nav { display: flex; justify-content: space-between; gap: 14px; margin-bottom: 64px; }
.article-nav a { flex: 1; text-decoration: none; background: var(--surface); border: 1px solid var(--line); border-radius: 12px; padding: 16px 18px; box-shadow: var(--shadow); transition: border-color .15s, transform .15s; }
.article-nav a:hover { transform: translateY(-2px); border-color: var(--line-strong); }
.article-nav a.next { text-align: right; }
.article-nav span { display: block; font-size: 12px; color: var(--ink-faint); font-weight: 700; text-transform: uppercase; letter-spacing: .06em; }
.article-nav b { font-family: var(--serif); font-weight: 700; font-size: 17px; }
.article-nav a.disabled { opacity: .35; pointer-events: none; }

.loading { color: var(--ink-faint); padding: 40px 0; text-align: center; }

/* ---------- Footer ---------- */
footer { background: var(--bg); color: #94a3b8; padding: 40px 0; font-size: 14px; }
footer .wrap { display: flex; flex-wrap: wrap; gap: 14px; justify-content: space-between; align-items: center; }
footer a { color: #cbd5e1; }
footer .src { max-width: 640px; font-size: 12.5px; line-height: 1.5; }