:root {
  --bg:           #f7f9fc;
  --panel:        #ffffff;
  --text:         #1c2838;
  --muted:        #5c6e82;
  --accent:       #2563eb;
  --accent-soft:  #3b82f6;
  --caap:         #5c3d9e;
  --caap-light:   #f3eeff;
  --ddrp-light:   #eff6ff;
  --border:       rgba(0,0,0,.08);
  --border-md:    rgba(0,0,0,.13);
  --codebg:       #f1f5f9;
  --success:      #16a34a;
  --success-bg:   #f0fdf4;
  --danger:       #dc2626;
  --warn:         #d97706;
  --radius:       16px;
  --shadow:       0 1px 3px rgba(0,0,0,.05), 0 0 0 1px rgba(0,0,0,.04);
  --shadow-lift:  0 4px 16px rgba(0,0,0,.09), 0 0 0 1px rgba(0,0,0,.05);
}

*, *::before, *::after { box-sizing: border-box; }

html {
  color: var(--text);
  background: var(--bg);
  font-family: ui-sans-serif, system-ui, -apple-system, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

body { margin: 0; min-height: 100vh; }

.wrap { max-width: 960px; margin: 0 auto; padding: 0 24px; }

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

p  { margin: .75em 0; }
h1 { font-size: clamp(26px, 4vw, 40px); line-height: 1.15; margin: 0 0 12px; font-weight: 700; }
h2 { font-size: 19px; margin: 0 0 10px; font-weight: 700; }
h3 { font-size: 15px; margin: 18px 0 7px; font-weight: 700; }
h3:first-child { margin-top: 0; }
ul, ol { margin: .6em 0 .6em 1.5em; }
li { margin: .35em 0; }
strong { color: var(--text); }

code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  background: var(--codebg);
  padding: .15em .4em;
  border-radius: 5px;
  font-size: .875em;
}
pre {
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  background: var(--codebg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  overflow-x: auto;
  font-size: .875em;
  line-height: 1.55;
  margin: 12px 0;
}

hr { border: none; border-top: 1px solid var(--border); margin: 0; }

/* Header */
header {
  padding: 48px 0 30px;
  border-bottom: 1px solid var(--border);
  background: var(--panel);
}

.kicker {
  color: var(--muted);
  letter-spacing: .09em;
  text-transform: uppercase;
  font-size: 11px;
  font-weight: 600;
  margin: 0 0 10px;
}

.sub {
  max-width: 68ch;
  color: var(--muted);
  margin: 0;
  font-size: 15px;
  line-height: 1.65;
}

/* Pills */
.pillrow { display: flex; gap: 6px; flex-wrap: wrap; margin-top: 14px; }

.pill {
  border: 1px solid var(--border-md);
  background: white;
  color: var(--muted);
  padding: 4px 11px;
  border-radius: 999px;
  font-size: 12px;
  white-space: nowrap;
  font-weight: 500;
}
.pill-ddrp { border-color: var(--accent-soft); color: var(--accent);  background: var(--ddrp-light); }
.pill-caap { border-color: var(--caap);         color: var(--caap);    background: var(--caap-light); }
.pill-ok   { border-color: var(--success);       color: var(--success); background: var(--success-bg); }

/* Site nav */
.site-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  padding: 18px 0 6px;
}

.site-nav a {
  border: 1px solid var(--border-md);
  background: white;
  color: var(--muted);
  padding: 5px 13px;
  border-radius: 999px;
  font-size: 13px;
  font-weight: 500;
  transition: border-color .12s, color .12s, background .12s;
  text-decoration: none;
}
.site-nav a:hover       { border-color: var(--accent-soft); color: var(--accent);  background: var(--ddrp-light); }
.site-nav a.active      { border-color: var(--accent-soft); color: var(--accent);  background: var(--ddrp-light); font-weight: 700; }
.site-nav a.active-caap { border-color: var(--caap);         color: var(--caap);    background: var(--caap-light); font-weight: 700; }
.site-nav .sep          { color: var(--border-md); align-self: center; padding: 0 2px; font-size: 14px; user-select: none; }

/* Main */
main { padding: 28px 0 64px; }

/* Grid */
.grid { display: grid; grid-template-columns: 1fr; gap: 16px; }
@media (min-width: 800px) {
  .grid { grid-template-columns: 1.3fr .7fr; align-items: start; gap: 20px; }
  .sticky { position: sticky; top: 20px; }
}

/* Cards */
.card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px 26px;
  margin-bottom: 14px;
  box-shadow: var(--shadow);
}
.card:last-child { margin-bottom: 0; }

/* TOC */
nav.toc strong { display: block; margin-bottom: 10px; font-size: 10px; letter-spacing: .1em; text-transform: uppercase; color: var(--muted); font-weight: 700; }
nav.toc ul     { margin: 0; padding-left: 14px; }
nav.toc > ul   { padding-left: 0; list-style: none; }
nav.toc li     { margin: 5px 0; font-size: 13px; }
nav.toc a      { color: var(--muted); font-weight: 500; }
nav.toc a:hover { color: var(--accent); text-decoration: none; }

/* Callout */
.callout {
  border-left: 4px solid var(--accent);
  background: rgba(37,99,235,.06);
  padding: 11px 15px;
  border-radius: 0 10px 10px 0;
  margin: 12px 0;
  font-size: .92em;
  line-height: 1.55;
}
.callout-caap { border-left-color: var(--caap); background: var(--caap-light); }
.callout-warn { border-left-color: var(--warn); background: #fffbeb; }
.callout strong { color: inherit; }

/* Key statement */
.key-statement { font-size: 1.05em; line-height: 1.95; margin: 12px 0; }

/* Schema */
.schema {
  font-weight: 700;
  letter-spacing: .04em;
  color: var(--accent);
  font-size: 1.05em;
  text-align: center;
  padding: .9em 0;
  background: var(--ddrp-light);
  border-radius: 10px;
  margin: 12px 0;
  border: 1px solid rgba(37,99,235,.14);
}

/* Two-panel */
.two-panel { display: grid; grid-template-columns: 1fr 1fr; gap: 11px; margin: 12px 0; }
@media (max-width: 560px) { .two-panel { grid-template-columns: 1fr; } }

.panel { padding: 14px 16px; border-radius: 12px; border: 1px solid var(--border); }
.panel h3 { margin: 0 0 8px; font-size: 11px; text-transform: uppercase; letter-spacing: .07em; color: var(--muted); font-weight: 700; }
.panel ul { margin: 0; padding-left: 16px; }
.panel li { font-size: .875em; margin: 3px 0; }
.panel-ddrp    { background: var(--ddrp-light); border-color: var(--accent-soft); }
.panel-caap    { background: var(--caap-light);  border-color: var(--caap); }
.panel-neutral { background: #f8fafc; }
.panel-warn    { background: #fff5f5; border-color: #fca5a5; }

/* Stack diagram */
.stack-diagram { border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden; margin: 14px 0; background: white; }
.stack-layer { display: flex; gap: 14px; padding: 14px 18px; border-bottom: 1px solid var(--border); }
.stack-layer:last-child { border-bottom: none; }
.layer-caap  { background: var(--caap-light); border-left: 5px solid var(--caap); }
.layer-iface { background: #f8fafc; border-left: 5px solid #cbd5e1; padding: 9px 18px 9px 13px; }
.layer-ddrp  { background: var(--ddrp-light); border-left: 5px solid var(--accent-soft); }
.layer-badge { font-size: 10px; font-weight: 700; letter-spacing: .11em; text-transform: uppercase; color: var(--muted); white-space: nowrap; padding-top: 3px; min-width: 52px; }
.layer-name  { font-size: 14px; font-weight: 700; color: var(--text); margin-bottom: 3px; }
.layer-desc  { font-size: 12px; color: var(--muted); line-height: 1.5; }

/* Feature grid */
.feature-grid { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 10px; margin: 12px 0; }
@media (max-width: 620px) { .feature-grid { grid-template-columns: 1fr; } }
.feature-card { padding: 14px 15px; border-radius: 12px; border: 1px solid var(--border); background: #fafbfc; }
.feature-card h4 { margin: 0 0 6px; font-size: 11px; text-transform: uppercase; letter-spacing: .07em; color: var(--muted); font-weight: 700; }
.feature-card p  { margin: 0; font-size: .85em; line-height: 1.55; }

/* Question cards */
.question-grid { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 10px; margin: 12px 0; }
@media (max-width: 560px) { .question-grid { grid-template-columns: 1fr; } }
.question-card { padding: 12px 14px; background: #fafbfc; border-radius: 10px; border: 1px solid var(--border); border-top: 3px solid var(--accent); font-size: 13px; text-align: center; line-height: 1.5; }

/* Pull quote */
.pull-quote { font-size: 1.02em; line-height: 1.75; border-left: 4px solid var(--accent); padding: 10px 16px; margin: 14px 0; font-style: italic; background: var(--ddrp-light); border-radius: 0 10px 10px 0; }

/* Comparison table */
.comparison-table { width: 100%; border-collapse: collapse; font-size: .84em; border-radius: 12px; overflow: hidden; border: 1px solid var(--border); margin: 12px 0; }
.comparison-table th { background: var(--text); color: white; padding: 9px 11px; text-align: left; font-weight: 600; font-size: .88em; }
.comparison-table th.col-ddrp  { background: var(--accent); }
.comparison-table th.col-caap  { background: var(--caap); }
.comparison-table th.col-stack { background: #1e3a5f; }
.comparison-table td { padding: 7px 11px; border-bottom: 1px solid var(--border); vertical-align: top; line-height: 1.45; }
.comparison-table tr:last-child td { border-bottom: none; }
.comparison-table tr:nth-child(even) td { background: #fafbfc; }
.comparison-table td:first-child { font-weight: 600; white-space: nowrap; }
.yes     { color: var(--success); font-weight: 700; }
.no      { color: var(--danger);  font-weight: 700; }
.partial { color: var(--warn);    font-weight: 700; }

/* Buttons */
.btn { display: inline-block; background: var(--accent); color: white !important; padding: 8px 20px; border-radius: 8px; font-weight: 600; font-size: 14px; text-decoration: none !important; transition: opacity .12s; }
.btn:hover        { opacity: .85; }
.btn-caap         { background: var(--caap); }
.btn-outline      { background: white !important; border: 1.5px solid var(--accent); color: var(--accent) !important; padding: 6px 18px; }
.btn-outline-caap { background: white !important; border: 1.5px solid var(--caap);  color: var(--caap)  !important; padding: 6px 18px; }
.btn-row          { display: flex; flex-wrap: wrap; gap: 10px; margin: 18px 0; }
.btn-row.center   { justify-content: center; }

/* Download cards */
.download-card { background: white; border: 1px solid var(--border); border-radius: var(--radius); padding: 18px 22px; display: flex; justify-content: space-between; align-items: flex-start; gap: 16px; margin-bottom: 12px; transition: box-shadow .15s, border-color .15s; }
.download-card:hover { box-shadow: var(--shadow-lift); border-color: var(--accent-soft); }
.download-body h3 { margin: 0 0 5px; font-size: 15px; }
.download-body p  { margin: 0; font-size: 13px; color: var(--muted); line-height: 1.5; }
.download-body { flex: 1; }
.download-action  { white-space: nowrap; padding-top: 2px; }
@media (max-width: 540px) { .download-card { flex-direction: column; } }

/* Footer */
footer { padding: 22px 0 36px; border-top: 1px solid var(--border); color: var(--muted); font-size: 13px; background: var(--panel); }
footer p       { margin: 4px 0; text-align: center; }
footer a       { color: var(--muted); }
footer a:hover { color: var(--accent); text-decoration: none; }