/* =========================================================================
   cacheinvalidation.org — elegant, professional light theme
   ========================================================================= */
:root {
  /* Palette — Redis-inspired crimson with indigo/teal accents on warm off-white */
  --crimson: #b91c2c;
  --crimson-600: #a3162a;
  --crimson-700: #861226;
  --indigo: #4f46e5;
  --indigo-700: #4338ca;
  --teal: #0d9488;
  --amber: #d97706;

  --bg: #fbf8f6;
  --surface: #ffffff;
  --surface-2: #f6f1ee;
  --ink: #1f2430;
  --ink-soft: #4a5160;
  --muted: #6b7280;
  --line: #e8ded8;
  --line-strong: #d9ccc4;

  --code-bg: #fdf6f4;
  --code-ink: #3a2f2c;
  --inline-code-bg: #f4ece8;
  --inline-code-ink: #9a1f33;

  --accent: var(--crimson);
  --accent-ink: #fff;

  --radius: 14px;
  --radius-sm: 9px;
  --shadow-sm: 0 1px 2px rgba(31, 36, 48, .05), 0 1px 3px rgba(31, 36, 48, .07);
  --shadow-md: 0 6px 20px -6px rgba(31, 36, 48, .18);
  --shadow-lg: 0 20px 48px -16px rgba(133, 18, 38, .28);

  --header-h: 64px;
  --maxw: 1280px;       /* overall site width on widescreen */
  --content-maxw: 980px; /* comfortable measure that still fills its container */

  --font-sans: "Inter", system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-mono: "JetBrains Mono", "SFMono-Regular", ui-monospace, "Cascadia Code", Menlo, Consolas, monospace;

  --transition: 180ms cubic-bezier(.4, 0, .2, 1);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  font-family: var(--font-sans);
  color: var(--ink);
  background: var(--bg);
  line-height: 1.7;
  font-size: 17px;
  /* Sticky footer */
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  background-image:
    radial-gradient(1200px 500px at 85% -120px, rgba(99, 102, 241, .07), transparent 60%),
    radial-gradient(1000px 460px at -10% -80px, rgba(185, 28, 44, .07), transparent 60%);
  background-attachment: fixed;
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { transition: none !important; animation: none !important; }
}

.site-main { flex: 1 0 auto; width: 100%; }

a { color: var(--crimson-600); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--indigo-700); }

.skip-link {
  position: absolute; left: -999px; top: 0; z-index: 1000;
  background: var(--crimson); color: #fff; padding: .6rem 1rem; border-radius: 0 0 var(--radius-sm) 0;
}
.skip-link:focus { left: 0; }

:focus-visible { outline: 3px solid rgba(79, 70, 229, .5); outline-offset: 2px; border-radius: 4px; }

/* ------------------------------------------------------------------ header */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: rgba(255, 255, 255, .82);
  backdrop-filter: saturate(160%) blur(12px);
  border-bottom: 1px solid var(--line);
  box-shadow: var(--shadow-sm);
}
.header-inner {
  max-width: var(--maxw); margin: 0 auto; padding: 0 clamp(1rem, 3vw, 2.4rem);
  height: var(--header-h);
  display: flex; align-items: center; gap: 1rem;
}
.brand { display: inline-flex; align-items: center; gap: .6rem; font-size: 1.18rem; color: var(--ink); }
.brand:hover { color: var(--ink); }
.brand .logo-mark { width: 34px; height: 34px; transition: transform var(--transition); }
.brand:hover .logo-mark { transform: rotate(-8deg) scale(1.06); }
.brand-text { font-weight: 600; letter-spacing: -.01em; }
.brand-text strong { color: var(--crimson); font-weight: 800; }
.brand-dot { color: var(--indigo); font-weight: 700; }

.site-nav { margin-left: auto; }
.site-nav ul { list-style: none; display: flex; gap: .35rem; margin: 0; padding: 0; }
.nav-link {
  display: inline-flex; align-items: center; gap: .45rem;
  padding: .5rem .85rem; border-radius: 999px; color: var(--ink-soft); font-weight: 550;
  font-size: .95rem; transition: all var(--transition); border: 1px solid transparent;
}
.nav-icon { width: 18px; height: 18px; flex: none; }
.nav-link:hover { color: var(--crimson); background: var(--surface-2); }
.nav-link.is-active {
  color: var(--crimson); background: #fff;
  border-color: var(--line-strong); box-shadow: var(--shadow-sm);
}
.nav-link.is-active .nav-icon { color: var(--crimson); }

/* mobile nav */
.nav-toggle, .nav-burger { display: none; }
.nav-burger { width: 42px; height: 42px; margin-left: auto; cursor: pointer; border-radius: 10px; }
.nav-burger span { display: block; height: 2px; background: var(--ink); margin: 5px 9px; border-radius: 2px; transition: var(--transition); }

@media (max-width: 760px) {
  .site-nav {
    position: fixed; inset: var(--header-h) 0 auto 0; margin: 0;
    background: rgba(255,255,255,.98); border-bottom: 1px solid var(--line);
    box-shadow: var(--shadow-md);
    max-height: 0; overflow: hidden; transition: max-height var(--transition);
  }
  .site-nav ul { flex-direction: column; padding: .6rem; gap: .2rem; }
  .nav-link { width: 100%; }
  .nav-burger { display: block; }
  .nav-toggle:checked ~ .site-nav { max-height: 70vh; }
  .nav-toggle:checked ~ .nav-burger span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
  .nav-toggle:checked ~ .nav-burger span:nth-child(2) { opacity: 0; }
  .nav-toggle:checked ~ .nav-burger span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }
}

/* ------------------------------------------------------------------ page */
.page {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: clamp(1.4rem, 3vw, 2.8rem) clamp(1rem, 3vw, 2.4rem) 3.5rem;
}

.breadcrumbs ol {
  list-style: none; display: flex; flex-wrap: wrap; gap: .35rem; padding: 0; margin: 0 0 1.4rem;
  font-size: .85rem; color: var(--muted);
}
.breadcrumbs li { display: flex; align-items: center; }
.breadcrumbs li + li::before { content: "›"; margin: 0 .5rem; color: var(--line-strong); }
.breadcrumbs a { color: var(--muted); }
.breadcrumbs a:hover { color: var(--crimson); }
.breadcrumbs li[aria-current] { color: var(--ink-soft); font-weight: 600; }

/* Content fills its container (which is centred & matches the header width),
   so it lines up with the app bar — not a narrow column, not full page width. */
.content { max-width: 100%; }

/* --------------------------------------------------------- content typography */
.content h1 {
  font-size: clamp(1.9rem, 1.2rem + 2.4vw, 2.9rem);
  line-height: 1.12; letter-spacing: -.02em; margin: .2rem 0 1.1rem;
  background: linear-gradient(120deg, var(--crimson) 0%, var(--indigo) 70%);
  -webkit-background-clip: text; background-clip: text; color: transparent;
  font-weight: 800;
}
.content h2 {
  font-size: clamp(1.4rem, 1.1rem + 1vw, 1.85rem); margin: 2.4rem 0 .9rem;
  letter-spacing: -.01em; color: var(--ink); font-weight: 750;
  padding-bottom: .35rem; border-bottom: 2px solid var(--line);
}
.content h3 { font-size: 1.28rem; margin: 1.8rem 0 .7rem; color: var(--crimson-700); font-weight: 700; }
.content h4 { font-size: 1.08rem; margin: 1.4rem 0 .5rem; color: var(--ink); font-weight: 700; }
.content h2, .content h3, .content h4 { scroll-margin-top: calc(var(--header-h) + 18px); }
.content p { margin: 0 0 1.1rem; color: var(--ink-soft); }
.content strong { color: var(--ink); }
.content > :first-child { margin-top: 0; }

.content ul, .content ol { padding-left: 1.4rem; margin: 0 0 1.2rem; }
.content li { margin: .35rem 0; color: var(--ink-soft); }
.content li::marker { color: var(--crimson); }

.content blockquote {
  margin: 1.4rem 0; padding: .2rem 1.2rem; border-left: 4px solid var(--indigo);
  background: var(--surface-2); border-radius: 0 var(--radius-sm) var(--radius-sm) 0; color: var(--ink-soft);
}
.content hr { border: 0; border-top: 1px solid var(--line); margin: 2.2rem 0; }

/* content links */
.content a {
  color: var(--crimson-600); font-weight: 550;
  background-image: linear-gradient(var(--indigo), var(--indigo));
  background-size: 0% 2px; background-repeat: no-repeat; background-position: 0 100%;
  transition: background-size var(--transition), color var(--transition);
}
.content a:hover { color: var(--indigo-700); background-size: 100% 2px; }

/* anchor link on headings */
.header-anchor {
  text-decoration: none; color: var(--line-strong); padding-right: .4rem; margin-left: -1.1rem;
  opacity: 0; transition: opacity var(--transition); background: none;
}
.content h2:hover .header-anchor, .content h3:hover .header-anchor, .content h4:hover .header-anchor { opacity: 1; }
.header-anchor:hover { color: var(--crimson); background: none; }

/* ----------------------------------------------------------- inline code */
.content :not(pre) > code {
  font-family: var(--font-mono); font-size: .9em;
  background: var(--inline-code-bg); color: var(--inline-code-ink);
  padding: .12em .42em; border-radius: 6px; border: 0; white-space: nowrap;
}

/* ------------------------------------------------------------- code blocks */
.content pre[class*="language-"], .content pre {
  position: relative; margin: 0 0 1.4rem; padding: 1.1rem 1.15rem; overflow: auto;
  background: var(--code-bg); color: var(--code-ink);
  border: 1px solid var(--line); border-radius: var(--radius);
  box-shadow: var(--shadow-sm); font-size: .9rem; line-height: 1.6;
  tab-size: 2;
}
.content pre code { font-family: var(--font-mono); background: none; padding: 0; border: 0; white-space: pre; color: inherit; }

.code-wrap { position: relative; }
.copy-btn {
  position: absolute; top: .55rem; right: .55rem; z-index: 2;
  display: inline-flex; align-items: center; gap: .35rem;
  font: 600 .76rem var(--font-sans); color: var(--ink-soft);
  background: rgba(255,255,255,.9); border: 1px solid var(--line-strong);
  padding: .3rem .55rem; border-radius: 8px; cursor: pointer;
  opacity: 0; transition: all var(--transition); backdrop-filter: blur(4px);
}
.code-wrap:hover .copy-btn, .copy-btn:focus-visible { opacity: 1; }
.copy-btn:hover { color: var(--crimson); border-color: var(--crimson); }
.copy-btn.copied { color: var(--teal); border-color: var(--teal); }
.copy-btn svg { width: 14px; height: 14px; }

/* Prism light token theme tuned to palette */
.token.comment, .token.prolog, .token.doctype, .token.cdata { color: #9a8f8a; font-style: italic; }
.token.punctuation { color: #6b5d57; }
.token.property, .token.tag, .token.boolean, .token.number, .token.constant, .token.symbol, .token.deleted { color: #b91c2c; }
.token.selector, .token.attr-name, .token.string, .token.char, .token.builtin, .token.inserted { color: #0d7d70; }
.token.operator, .token.entity, .token.url, .language-css .token.string, .style .token.string { color: #9a1f33; }
.token.atrule, .token.attr-value, .token.keyword { color: #4338ca; font-weight: 600; }
.token.function, .token.class-name { color: #c2410c; }
.token.regex, .token.important, .token.variable { color: #b45309; }
.token.important, .token.bold { font-weight: 700; }
.token.italic { font-style: italic; }

/* mermaid diagrams */
.content pre.mermaid {
  margin: 0 0 1.5rem; padding: 1.4rem 1rem; background: var(--surface);
  border: 1px solid var(--line); border-radius: var(--radius); text-align: center;
  box-shadow: var(--shadow-sm); overflow-x: auto; white-space: normal;
  position: relative; line-height: normal; color: var(--ink);
}
.content pre.mermaid svg { max-width: 100%; height: auto; }
/* before render, hide the raw definition flash */
.content pre.mermaid:not([data-processed]) { color: transparent; min-height: 4rem; }

.content pre.mermaid.mermaid-zoomable { cursor: zoom-in; transition: box-shadow var(--transition), border-color var(--transition); }
.content pre.mermaid.mermaid-zoomable:hover { border-color: var(--crimson); box-shadow: var(--shadow-md); }
.content pre.mermaid.mermaid-zoomable::after {
  content: "⤢ click to enlarge"; position: absolute; bottom: .5rem; right: .7rem;
  font: 600 .72rem var(--font-sans); color: var(--muted);
  background: rgba(255, 255, 255, .85); border: 1px solid var(--line);
  padding: .2rem .5rem; border-radius: 999px; opacity: 0; transition: opacity var(--transition);
  pointer-events: none;
}
.content pre.mermaid.mermaid-zoomable:hover::after { opacity: 1; }

/* fullscreen lightbox */
body.diagram-modal-open { overflow: hidden; }
.diagram-modal {
  position: fixed; inset: 0; z-index: 1000; display: flex; flex-direction: column;
  align-items: center; justify-content: center; gap: 1rem;
  background: rgba(28, 31, 41, .72); backdrop-filter: blur(6px);
  padding: 2vh 2vw; cursor: zoom-out; animation: diagram-fade var(--transition);
}
.diagram-modal[hidden] { display: none; }
@keyframes diagram-fade { from { opacity: 0; } to { opacity: 1; } }
.diagram-modal-stage {
  background: var(--surface); border-radius: var(--radius); padding: 1.2rem;
  box-shadow: var(--shadow-lg); cursor: default; max-width: 96vw; max-height: 90vh;
  display: flex; align-items: center; justify-content: center;
}
.diagram-modal-stage svg { display: block; }
.diagram-modal-close {
  position: absolute; top: 1.1rem; right: 1.3rem; width: 44px; height: 44px;
  font-size: 1.8rem; line-height: 1; color: #fff; background: rgba(255, 255, 255, .14);
  border: 1px solid rgba(255, 255, 255, .35); border-radius: 50%; cursor: pointer;
  transition: background var(--transition);
}
.diagram-modal-close:hover { background: rgba(255, 255, 255, .28); }
.diagram-modal-hint { margin: 0; color: rgba(255, 255, 255, .85); font-size: .85rem; }

/* ----------------------------------------------------------------- tables */
.table-scroll {
  overflow-x: auto; margin: 0 0 1.5rem; border: 1px solid var(--line);
  border-radius: var(--radius); box-shadow: var(--shadow-sm); -webkit-overflow-scrolling: touch;
}
.content table { border-collapse: collapse; width: 100%; min-width: 520px; font-size: .92rem; background: var(--surface); }
.content thead th { background: linear-gradient(120deg, var(--crimson), var(--crimson-700)); color: #fff; font-weight: 650; text-align: left; }
.content th, .content td { padding: .7rem .9rem; border-bottom: 1px solid var(--line); vertical-align: top; }
.content tbody tr:nth-child(even) { background: var(--surface-2); }
.content tbody tr:hover { background: #fdeef0; }
.content td code { white-space: normal; }

/* ------------------------------------------------------------- task lists */
.content ul:has(> li.task-list-item) { list-style: none; padding-left: .25rem; }
.content li.task-list-item { display: flex; align-items: flex-start; gap: .6rem; list-style: none; }
.content li.task-list-item::marker { content: ""; }
.content li.task-list-item input[type="checkbox"] {
  appearance: none; -webkit-appearance: none; margin: .35rem 0 0; flex: none;
  width: 1.15rem; height: 1.15rem; border: 2px solid var(--line-strong); border-radius: 6px;
  background: var(--surface); cursor: pointer; transition: all var(--transition); position: relative;
}
.content li.task-list-item input[type="checkbox"]:hover { border-color: var(--crimson); }
.content li.task-list-item input[type="checkbox"]:checked { background: var(--crimson); border-color: var(--crimson); }
.content li.task-list-item input[type="checkbox"]:checked::after {
  content: ""; position: absolute; left: 5px; top: 1px; width: 5px; height: 10px;
  border: solid #fff; border-width: 0 2px 2px 0; transform: rotate(45deg);
}
.content li.task-list-item.is-checked { color: var(--muted); text-decoration: line-through; text-decoration-color: var(--line-strong); }

/* ------------------------------------------------------------- accordions (FAQ) */
.content details.faq {
  border: 1px solid var(--line); border-radius: var(--radius-sm); margin: 0 0 .8rem;
  background: var(--surface); box-shadow: var(--shadow-sm); overflow: hidden;
}
.content details.faq > summary {
  cursor: pointer; list-style: none; padding: 1rem 1.2rem; font-weight: 650; color: var(--ink);
  display: flex; justify-content: space-between; align-items: center; gap: 1rem; transition: background var(--transition);
}
.content details.faq > summary::-webkit-details-marker { display: none; }
.content details.faq > summary::after { content: "+"; font-size: 1.3rem; color: var(--crimson); transition: transform var(--transition); }
.content details.faq[open] > summary { background: var(--surface-2); }
.content details.faq[open] > summary::after { transform: rotate(45deg); }
.content details.faq > summary:hover { background: var(--surface-2); }
.content details.faq > .faq-body { padding: .2rem 1.2rem 1rem; color: var(--ink-soft); }

/* ----------------------------------------------------------- related nav */
.related { margin-top: 3rem; padding-top: 1.8rem; border-top: 1px solid var(--line); display: grid; gap: 1.8rem; }
.related-title { font-size: .82rem; text-transform: uppercase; letter-spacing: .08em; color: var(--muted); margin: 0 0 .9rem; }
.related-list { list-style: none; padding: 0; margin: 0; display: grid; gap: .6rem; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); }
.related-list a {
  display: flex; align-items: center; gap: .6rem; padding: .85rem 1rem; background: var(--surface);
  border: 1px solid var(--line); border-radius: var(--radius-sm); color: var(--ink); font-weight: 550;
  box-shadow: var(--shadow-sm); transition: all var(--transition); background-image: none;
}
.related-list a:hover { border-color: var(--crimson); transform: translateY(-2px); box-shadow: var(--shadow-md); color: var(--crimson); }
.related-arrow { color: var(--crimson); font-weight: 700; transition: transform var(--transition); }
.related-list a:hover .related-arrow { transform: translateX(3px); }

/* ------------------------------------------------------------------ footer */
.site-footer { flex-shrink: 0; margin-top: 2rem; background: #1c1f29; color: #cdd2de; }
.footer-inner {
  max-width: var(--maxw); margin: 0 auto; padding: 2.4rem clamp(1rem, 3vw, 2.4rem);
  display: flex; flex-wrap: wrap; align-items: center; gap: 1.2rem 2rem;
}
.footer-brand { display: inline-flex; align-items: center; gap: .6rem; font-weight: 700; color: #fff; }
.footer-brand .logo-mark { width: 30px; height: 30px; }
.footer-nav { display: flex; flex-wrap: wrap; gap: 1.2rem; margin-left: auto; }
.footer-nav a { color: #cdd2de; font-weight: 500; }
.footer-nav a:hover { color: #fff; }
.footer-meta { flex-basis: 100%; margin: .4rem 0 0; color: #8b91a1; font-size: .86rem; }

/* ============================================================ FRONT PAGE */
.hero { max-width: var(--maxw); margin: 0 auto; padding: clamp(2rem, 5vw, 4.5rem) clamp(1rem, 3vw, 2.4rem) 1rem; text-align: center; }
.hero-logo { width: clamp(96px, 16vw, 150px); height: auto; margin: 0 auto 1.4rem; display: block; filter: drop-shadow(0 14px 26px rgba(133,18,38,.22)); transition: transform var(--transition); }
.hero-logo:hover { transform: translateY(-4px) rotate(-3deg); }
.hero h1 {
  font-size: clamp(2rem, 1.2rem + 3.4vw, 3.6rem); line-height: 1.08; letter-spacing: -.025em; margin: 0 auto .4rem; max-width: 18ch; font-weight: 850;
  background: linear-gradient(115deg, var(--crimson) 0%, var(--indigo) 60%, var(--teal) 100%);
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.hero .tagline { font-size: clamp(1.05rem, 1rem + .4vw, 1.3rem); color: var(--ink-soft); max-width: 60ch; margin: 0 auto 2rem; }
.hero-ctas { display: flex; flex-wrap: wrap; justify-content: center; gap: .9rem; margin-bottom: .5rem; }
.cta {
  display: inline-flex; align-items: center; gap: .6rem; padding: .85rem 1.3rem; border-radius: 999px;
  font-weight: 650; font-size: 1rem; border: 1px solid var(--line-strong); background: var(--surface);
  color: var(--ink); box-shadow: var(--shadow-sm); transition: all var(--transition);
}
.cta:hover { transform: translateY(-3px); box-shadow: var(--shadow-lg); color: var(--ink); border-color: transparent; }
.cta .cta-ico { width: 26px; height: 26px; display: grid; place-items: center; border-radius: 8px; color: #fff; flex: none; }
.cta .cta-ico svg { width: 16px; height: 16px; }
.cta-1 .cta-ico { background: linear-gradient(135deg, #ef4444, #b91c2c); }
.cta-2 .cta-ico { background: linear-gradient(135deg, #6366f1, #4338ca); }
.cta-3 .cta-ico { background: linear-gradient(135deg, #14b8a6, #0d9488); }
.cta-primary { background: linear-gradient(135deg, var(--crimson), var(--crimson-700)); color: #fff; border-color: transparent; }
.cta-primary:hover { color: #fff; }

.home-section { max-width: var(--maxw); margin: 0 auto; padding: 1.5rem clamp(1rem, 3vw, 2.4rem); }
.home-intro { max-width: 70ch; margin: 1rem auto 2.5rem; text-align: center; color: var(--ink-soft); }
.home-intro p { margin: 0 0 1rem; }

.section-grid { display: grid; gap: 1.4rem; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); margin-bottom: 3rem; }
.section-card {
  display: flex; flex-direction: column; padding: 1.6rem; background: var(--surface); border: 1px solid var(--line);
  border-radius: var(--radius); box-shadow: var(--shadow-sm); transition: all var(--transition); background-image: none; color: var(--ink);
}
.section-card:hover { transform: translateY(-5px); box-shadow: var(--shadow-lg); border-color: transparent; color: var(--ink); }
.section-card .card-ico { width: 46px; height: 46px; border-radius: 12px; display: grid; place-items: center; color: #fff; margin-bottom: 1rem; }
.section-card .card-ico svg { width: 24px; height: 24px; }
.section-card.c1 .card-ico { background: linear-gradient(135deg, #6366f1, #4338ca); }
.section-card.c2 .card-ico { background: linear-gradient(135deg, #ef4444, #b91c2c); }
.section-card.c3 .card-ico { background: linear-gradient(135deg, #14b8a6, #0d9488); }
.section-card h3 { margin: 0 0 .5rem; font-size: 1.2rem; color: var(--ink); }
.section-card p { margin: 0 0 1rem; color: var(--ink-soft); font-size: .95rem; flex: 1; }
.section-card .card-links { list-style: none; padding: 0; margin: 0 0 1rem; display: grid; gap: .3rem; }
.section-card .card-links a { font-size: .9rem; color: var(--crimson-600); font-weight: 550; }
.section-card .card-links a:hover { color: var(--indigo-700); }
.section-card .card-go { margin-top: auto; font-weight: 650; color: var(--crimson); display: inline-flex; align-items: center; gap: .35rem; }
.section-card:hover .card-go { gap: .6rem; }

.home-cta-banner {
  max-width: var(--maxw); margin: 0 auto 3rem; padding: clamp(1.6rem, 3vw, 2.4rem);
  background: linear-gradient(120deg, #fff 0%, var(--surface-2) 100%);
  border: 1px solid var(--line); border-radius: var(--radius); text-align: center;
}
.home-cta-banner h2 { margin: 0 0 .5rem; color: var(--ink); }
.home-cta-banner p { margin: 0 auto 1.2rem; max-width: 56ch; color: var(--ink-soft); }