/* ==================================================================
   QueryPlan.org — design system
   Light, elegant, professional palette inspired by query/data tooling.
   ================================================================== */

:root {
  /* palette */
  --c-bg: #f7f9fc;
  --c-surface: #ffffff;
  --c-surface-2: #eef3fa;
  --c-ink: #16243a;
  --c-ink-soft: #45566f;
  --c-muted: #6b7a90;
  --c-border: #e2e8f2;
  --c-border-strong: #cdd8e8;

  --c-primary: #2563a6;
  --c-primary-strong: #1e4f86;
  --c-primary-soft: #e8f1fb;
  --c-accent: #1f9e8a;       /* teal */
  --c-accent-soft: #e2f5f0;
  --c-amber: #e9a23b;
  --c-coral: #e9694a;
  --c-violet: #7c6bd6;

  --c-code-bg: #f4f7fb;
  --c-inline-bg: #eaf0f8;

  /* type */
  --font-sans: "Inter", "Segoe UI", system-ui, -apple-system, "Helvetica Neue", Arial, sans-serif;
  --font-mono: "JetBrains Mono", "SFMono-Regular", "Consolas", "Liberation Mono", Menlo, monospace;

  /* scale */
  --step--1: clamp(0.82rem, 0.8rem + 0.1vw, 0.9rem);
  --step-0: clamp(1rem, 0.96rem + 0.2vw, 1.08rem);
  --step-1: clamp(1.2rem, 1.1rem + 0.5vw, 1.4rem);
  --step-2: clamp(1.45rem, 1.3rem + 0.8vw, 1.85rem);
  --step-3: clamp(1.8rem, 1.5rem + 1.4vw, 2.6rem);
  --step-4: clamp(2.2rem, 1.7rem + 2.6vw, 3.6rem);

  /* layout */
  --maxw: 1320px;
  --maxw-prose: 78ch;
  --header-h: 64px;
  --radius: 14px;
  --radius-sm: 9px;
  --gap: clamp(1rem, 0.6rem + 1.4vw, 2rem);

  --shadow-sm: 0 1px 2px rgba(22, 36, 58, 0.06), 0 1px 3px rgba(22, 36, 58, 0.08);
  --shadow-md: 0 6px 20px rgba(22, 36, 58, 0.10);
  --shadow-lg: 0 18px 50px rgba(22, 36, 58, 0.16);
  --ring: 0 0 0 3px rgba(37, 99, 166, 0.28);

  --t: 180ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* ---------- reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: var(--step-0);
  line-height: 1.7;
  color: var(--c-ink);
  background: var(--c-bg);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  /* sticky footer */
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
}
img, svg { max-width: 100%; height: auto; }
h1, h2, h3, h4 { line-height: 1.22; color: var(--c-ink); font-weight: 700; }

a { color: var(--c-primary); text-decoration: none; transition: color var(--t); }
a:hover { color: var(--c-primary-strong); }

:focus-visible { outline: none; box-shadow: var(--ring); border-radius: 6px; }

.container { width: 100%; max-width: var(--maxw); margin-inline: auto; padding-inline: clamp(1rem, 3vw, 2.5rem); }

.skip-link {
  position: absolute; left: 0; top: -100%;
  background: var(--c-primary); color: #fff; padding: 0.6rem 1rem; z-index: 200;
  border-radius: 0 0 8px 0;
}
.skip-link:focus { top: 0; color:#fff; }

/* ---------- header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: rgba(255, 255, 255, 0.82);
  backdrop-filter: saturate(160%) blur(10px);
  border-bottom: 1px solid var(--c-border);
}
.site-header__inner { display: flex; align-items: center; justify-content: space-between; height: var(--header-h); gap: 1rem; }

.brand { display: inline-flex; align-items: center; gap: 0.6rem; font-weight: 800; color: var(--c-ink); letter-spacing: -0.01em; }
.brand__logo { display: block; transition: transform var(--t); }
.brand:hover .brand__logo { transform: rotate(-6deg) scale(1.06); }
.brand__name { font-size: 1.15rem; }
.brand__dot { color: var(--c-accent); }

.primary-nav__list { display: flex; gap: 0.15rem; list-style: none; margin: 0; padding: 0; }
.nav-link {
  display: inline-flex; align-items: center; gap: 0.45rem;
  padding: 0.45rem 0.7rem; border-radius: 999px; color: var(--c-ink-soft);
  font-weight: 600; font-size: 0.9rem; white-space: nowrap;
  transition: background var(--t), color var(--t), transform var(--t);
}
.nav-link__icon { width: 18px; height: 18px; flex: none; fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
.nav-link:hover { background: var(--c-primary-soft); color: var(--c-primary-strong); transform: translateY(-1px); }
.nav-link.is-active { background: var(--c-primary); color: #fff; }
.nav-link.is-active:hover { color: #fff; }
/* per-pillar accent on the icon (subdued until hover/active) */
.nav-link--p1 .nav-link__icon { stroke: var(--c-primary); }
.nav-link--p2 .nav-link__icon { stroke: var(--c-accent); }
.nav-link--p3 .nav-link__icon { stroke: var(--c-violet); }
.nav-link.is-active .nav-link__icon { stroke: #fff; }

.nav-toggle { display: none; background: none; border: 0; cursor: pointer; padding: 0.5rem; border-radius: 8px; }
.nav-toggle__bar { display: block; width: 22px; height: 2px; background: var(--c-ink); border-radius: 2px; transition: transform var(--t), opacity var(--t); }
.nav-toggle__bar + .nav-toggle__bar { margin-top: 5px; }
.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ---------- main / footer scaffolding ---------- */
.site-main { flex: 1 0 auto; }
.section { padding-block: clamp(2.5rem, 1.5rem + 4vw, 5rem); }
.section--alt { background: var(--c-surface-2); border-block: 1px solid var(--c-border); }
.section__title { font-size: var(--step-3); margin: 0 0 0.5rem; }
.section__intro { color: var(--c-ink-soft); font-size: var(--step-1); margin-bottom: 2rem; }

/* ---------- hero ---------- */
.hero {
  position: relative; overflow: hidden;
  background:
    radial-gradient(900px 420px at 85% -10%, rgba(31, 158, 138, 0.14), transparent 60%),
    radial-gradient(800px 460px at 0% 0%, rgba(37, 99, 166, 0.16), transparent 55%),
    linear-gradient(180deg, #ffffff, var(--c-bg));
  border-bottom: 1px solid var(--c-border);
}
.hero__inner { padding-block: clamp(2.5rem, 1.5rem + 6vw, 6rem); text-align: center; }
.hero__logo-row { display: flex; justify-content: center; margin-bottom: 1.5rem; }
.hero__logo { filter: drop-shadow(0 14px 30px rgba(30, 79, 134, 0.28)); animation: floaty 6s ease-in-out infinite; }
@keyframes floaty { 0%, 100% { transform: translateY(0); } 50% { transform: translateY(-9px); } }
.hero__title { font-size: var(--step-4); margin: 0 auto 1rem; max-width: 20ch; letter-spacing: -0.02em; }
.hero__amp { color: var(--c-accent); }
.hero__lead { font-size: var(--step-1); color: var(--c-ink-soft); max-width: 60ch; margin: 0 auto 2rem; }
.hero__cta { display: flex; flex-wrap: wrap; gap: 0.8rem; justify-content: center; }

/* ---------- buttons ---------- */
.btn {
  --btn-accent: var(--c-primary);
  display: inline-flex; align-items: center; gap: 0.6rem;
  padding: 0.72rem 1.2rem; border-radius: 12px; font-weight: 650; font-size: 0.98rem;
  border: 1px solid transparent; cursor: pointer; transition: transform var(--t), box-shadow var(--t), background var(--t), border-color var(--t);
}
.btn__icon { display: inline-flex; width: 22px; height: 22px; }
.btn__icon svg { width: 22px; height: 22px; fill: none; stroke: currentColor; stroke-width: 1.9; stroke-linecap: round; stroke-linejoin: round; }
.btn--primary { background: linear-gradient(135deg, var(--c-primary), var(--c-primary-strong)); color: #fff; box-shadow: var(--shadow-md); }
.btn--primary:hover { color: #fff; transform: translateY(-2px); box-shadow: var(--shadow-lg); }
.btn__icon--explore { color: #cfe6ff; }
.btn--ghost { background: var(--c-surface); color: var(--c-ink); border-color: var(--c-border-strong); box-shadow: var(--shadow-sm); }
.btn--ghost:hover { transform: translateY(-2px); box-shadow: var(--shadow-md); border-color: var(--btn-accent); color: var(--c-ink); }
.btn--ghost .btn__icon { color: var(--btn-accent); }
.btn--icon-1 { --btn-accent: var(--c-primary); }
.btn--icon-2 { --btn-accent: var(--c-accent); }
.btn--icon-3 { --btn-accent: var(--c-violet); }

/* ---------- pillar grid (home) ---------- */
.pillar-grid { list-style: none; margin: 0; padding: 0; display: grid; gap: var(--gap); grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
.pillar-card {
  background: var(--c-surface); border: 1px solid var(--c-border); border-radius: var(--radius);
  padding: 1.4rem; box-shadow: var(--shadow-sm); display: flex; flex-direction: column; gap: 0.9rem;
  position: relative; overflow: hidden; transition: transform var(--t), box-shadow var(--t), border-color var(--t);
}
.pillar-card::before { content: ""; position: absolute; inset: 0 0 auto 0; height: 4px; background: var(--card-accent, var(--c-primary)); }
.pillar-card--1 { --card-accent: linear-gradient(90deg, #2563a6, #5ec7b4); }
.pillar-card--2 { --card-accent: linear-gradient(90deg, #1f9e8a, #7ee0c6); }
.pillar-card--3 { --card-accent: linear-gradient(90deg, #7c6bd6, #c9b8ff); }
.pillar-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); border-color: var(--c-border-strong); }
.pillar-card__head { display: flex; align-items: center; gap: 0.75rem; color: var(--c-ink); }
.pillar-card__badge { display: inline-flex; align-items: center; justify-content: center; width: 42px; height: 42px; border-radius: 11px; background: var(--c-primary-soft); flex: none; }
.pillar-card--2 .pillar-card__badge { background: var(--c-accent-soft); }
.pillar-card--3 .pillar-card__badge { background: #efeafd; }
.pillar-card__badge svg { width: 22px; height: 22px; fill: none; stroke: var(--c-primary); stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
.pillar-card--2 .pillar-card__badge svg { stroke: var(--c-accent); }
.pillar-card--3 .pillar-card__badge svg { stroke: var(--c-violet); }
.pillar-card__title { font-size: 1.12rem; margin: 0; }
.pillar-card__links { list-style: none; margin: 0; padding: 0; display: grid; gap: 0.35rem; }
.pillar-card__links a { color: var(--c-ink-soft); font-size: 0.95rem; display: inline-block; padding: 0.15rem 0; border-bottom: 1px solid transparent; }
.pillar-card__links a:hover { color: var(--c-primary-strong); border-bottom-color: currentColor; }
.pillar-card__more { margin-top: auto; font-weight: 650; font-size: 0.92rem; }
.pillar-card__more span { transition: transform var(--t); display: inline-block; }
.pillar-card__more:hover span { transform: translateX(4px); }

/* ---------- doc page ---------- */
.doc { padding-block: clamp(1.5rem, 1rem + 2vw, 3rem); }
.doc__header { margin-bottom: 1.6rem; }
.doc__kicker { text-transform: uppercase; letter-spacing: 0.12em; font-size: 0.78rem; font-weight: 700; color: var(--c-accent); margin: 0 0 0.4rem; }
.doc__title {
  font-size: var(--step-3); margin: 0; letter-spacing: -0.02em;
  background: linear-gradient(120deg, var(--c-primary-strong), var(--c-accent));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.doc__subtitle { color: var(--c-ink-soft); font-size: var(--step-1); margin-top: 0.8rem; }

/* breadcrumbs */
.breadcrumbs { margin-bottom: 1rem; }
.breadcrumbs ol { list-style: none; display: flex; flex-wrap: wrap; gap: 0.4rem; margin: 0; padding: 0; font-size: 0.88rem; color: var(--c-muted); }
.breadcrumbs li { display: inline-flex; align-items: center; gap: 0.4rem; }
.breadcrumbs a { color: var(--c-muted); }
.breadcrumbs a:hover { color: var(--c-primary); }
.breadcrumbs [aria-current="page"] { color: var(--c-ink); font-weight: 600; }
.breadcrumbs__sep { color: var(--c-border-strong); }

/* ---------- prose ---------- */
.prose { max-width: var(--maxw-prose); }
.prose--wide { max-width: min(100%, 90ch); }
.prose--full { max-width: none; }
/* widen doc body on desktop: full container width, not a narrow column */
.doc__body { max-width: min(100%, 86ch); }
@media (min-width: 1100px) { .doc__body { max-width: 100%; } }

.prose > * + * { margin-top: 1.1em; }
.prose h2 { font-size: var(--step-2); margin-top: 2.2em; padding-bottom: 0.3em; border-bottom: 2px solid var(--c-surface-2); }
.prose h3 { font-size: var(--step-1); margin-top: 1.8em; color: var(--c-primary-strong); }
.prose h4 { font-size: 1.05rem; margin-top: 1.5em; color: var(--c-ink-soft); }
.prose p, .prose li { color: var(--c-ink-soft); }
.prose strong { color: var(--c-ink); }
.prose ul, .prose ol { padding-left: 1.4em; }
.prose li + li { margin-top: 0.35em; }
.prose blockquote {
  margin: 1.4em 0; padding: 0.5em 1.2em; border-left: 4px solid var(--c-accent);
  background: var(--c-accent-soft); border-radius: 0 8px 8px 0; color: var(--c-ink-soft);
}

/* heading anchors + scroll offset under sticky header */
.prose :is(h1, h2, h3, h4, h5, h6) { scroll-margin-top: calc(var(--header-h) + 1rem); }
.header-anchor { color: var(--c-border-strong); margin-left: 0.4rem; opacity: 0; text-decoration: none; transition: opacity var(--t), color var(--t); }
.prose :is(h2, h3, h4):hover .header-anchor { opacity: 1; }
.header-anchor:hover { color: var(--c-primary); }

/* prose links */
.prose a:not(.btn) {
  color: var(--c-primary); font-weight: 550;
  background-image: linear-gradient(currentColor, currentColor);
  background-size: 0% 1.5px; background-repeat: no-repeat; background-position: 0 100%;
  transition: background-size var(--t), color var(--t);
}
.prose a:not(.btn):hover { color: var(--c-primary-strong); background-size: 100% 1.5px; }

/* inline code — soft, borderless, low focus */
.prose :not(pre) > code {
  font-family: var(--font-mono); font-size: 0.88em;
  background: var(--c-inline-bg); color: #234; padding: 0.12em 0.42em;
  border-radius: 6px; white-space: break-spaces;
}

/* ---------- code blocks ---------- */
.code-block {
  margin: 1.5em 0; border: 1px solid var(--c-border); border-radius: var(--radius-sm);
  overflow: hidden; background: var(--c-code-bg); box-shadow: var(--shadow-sm);
}
.code-block__bar {
  display: flex; align-items: center; justify-content: space-between;
  padding: 0.4rem 0.5rem 0.4rem 0.9rem; background: var(--c-surface-2);
  border-bottom: 1px solid var(--c-border);
}
.code-block__lang { font-family: var(--font-mono); font-size: 0.72rem; letter-spacing: 0.08em; color: var(--c-muted); font-weight: 700; }
.code-copy {
  display: inline-flex; align-items: center; gap: 0.35rem; cursor: pointer;
  border: 1px solid var(--c-border-strong); background: var(--c-surface); color: var(--c-ink-soft);
  font-size: 0.76rem; font-weight: 600; padding: 0.28rem 0.6rem; border-radius: 7px;
  transition: background var(--t), color var(--t), border-color var(--t);
}
.code-copy::before {
  content: ""; width: 13px; height: 13px; background: currentColor;
  -webkit-mask: var(--copy-icon) center / contain no-repeat; mask: var(--copy-icon) center / contain no-repeat;
  --copy-icon: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='currentColor' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Crect x='9' y='9' width='13' height='13' rx='2'/%3E%3Cpath d='M5 15H4a2 2 0 0 1-2-2V4a2 2 0 0 1 2-2h9a2 2 0 0 1 2 2v1'/%3E%3C/svg%3E");
}
.code-copy:hover { background: var(--c-primary-soft); color: var(--c-primary-strong); border-color: var(--c-primary); }
.code-copy.is-copied { background: var(--c-accent-soft); color: #14705f; border-color: var(--c-accent); }
.code-block pre[class*="language-"] { margin: 0; padding: 1rem 1.1rem; overflow-x: auto; background: var(--c-code-bg); font-size: 0.86rem; line-height: 1.6; }
.code-block code[class*="language-"] { font-family: var(--font-mono); }

/* ---------- tables ---------- */
.table-wrap { overflow-x: auto; margin: 1.5em 0; border: 1px solid var(--c-border); border-radius: var(--radius-sm); box-shadow: var(--shadow-sm); -webkit-overflow-scrolling: touch; }
.table-wrap table { border-collapse: collapse; width: 100%; min-width: 460px; font-size: 0.92rem; }
.table-wrap th, .table-wrap td { padding: 0.7rem 0.95rem; text-align: left; border-bottom: 1px solid var(--c-border); vertical-align: top; }
.table-wrap thead th { background: var(--c-surface-2); color: var(--c-ink); font-weight: 700; position: sticky; top: 0; }
.table-wrap tbody tr { transition: background var(--t); }
.table-wrap tbody tr:hover { background: var(--c-primary-soft); }
.table-wrap tbody tr:last-child td { border-bottom: 0; }

/* ---------- task checkboxes ---------- */
.prose ul.task-list { list-style: none; padding-left: 0.2em; }
.task-list__item { display: flex; align-items: flex-start; gap: 0.6em; }
.task-list__item input[type="checkbox"] {
  appearance: none; -webkit-appearance: none; margin: 0.25em 0 0; flex: none;
  width: 1.15em; height: 1.15em; border: 2px solid var(--c-border-strong); border-radius: 5px;
  background: var(--c-surface); cursor: pointer; transition: background var(--t), border-color var(--t); position: relative;
}
.task-list__item input[type="checkbox"]:hover { border-color: var(--c-primary); }
.task-list__item input[type="checkbox"]:checked { background: var(--c-primary); border-color: var(--c-primary); }
.task-list__item input[type="checkbox"]:checked::after {
  content: ""; position: absolute; left: 4px; top: 1px; width: 4px; height: 8px;
  border: solid #fff; border-width: 0 2px 2px 0; transform: rotate(45deg);
}
.task-list__item.is-checked > .task-list__text { text-decoration: line-through; color: var(--c-muted); }

/* ---------- FAQ accordion ---------- */
.accordion { border: 1px solid var(--c-border); border-radius: var(--radius-sm); margin: 0.7em 0; background: var(--c-surface); overflow: hidden; box-shadow: var(--shadow-sm); }
.accordion__trigger {
  width: 100%; text-align: left; background: none; border: 0; cursor: pointer;
  padding: 0.95rem 1.1rem; font-size: 1.02rem; font-weight: 650; color: var(--c-ink);
  display: flex; align-items: center; justify-content: space-between; gap: 1rem; font-family: inherit;
}
.accordion__trigger:hover { background: var(--c-surface-2); color: var(--c-primary-strong); }
.accordion__icon { flex: none; width: 18px; height: 18px; position: relative; transition: transform var(--t); }
.accordion__icon::before, .accordion__icon::after { content: ""; position: absolute; background: currentColor; border-radius: 2px; }
.accordion__icon::before { top: 8px; left: 0; width: 18px; height: 2px; }
.accordion__icon::after { left: 8px; top: 0; width: 2px; height: 18px; transition: transform var(--t); }
.accordion[open] .accordion__icon::after { transform: rotate(90deg); opacity: 0; }
.accordion__panel { padding: 0 1.1rem 1.1rem; color: var(--c-ink-soft); }

/* ---------- mermaid + katex ---------- */
.mermaid { margin: 1.5em 0; text-align: center; background: var(--c-surface); border: 1px solid var(--c-border); border-radius: var(--radius-sm); padding: 1.2rem; box-shadow: var(--shadow-sm); overflow-x: auto; }
.mermaid:not([data-processed]):not(.mermaid--fallback) { color: transparent; min-height: 60px; }
.mermaid--fallback { white-space: pre-wrap; font-family: var(--font-mono); font-size: 0.85rem; text-align: left; color: var(--c-ink-soft); }
.katex-block { overflow-x: auto; overflow-y: hidden; padding: 0.6em 0; }
.katex { font-size: 1.04em; }

/* ---------- related ---------- */
.related { margin-top: 3rem; padding-top: 1.8rem; border-top: 1px solid var(--c-border); }
.related__title { font-size: var(--step-1); margin: 0 0 1rem; }
.related__grid { list-style: none; margin: 0; padding: 0; display: grid; gap: 0.8rem; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); }
.related__card a {
  display: flex; align-items: center; gap: 0.6rem; height: 100%;
  background: var(--c-surface); border: 1px solid var(--c-border); border-radius: var(--radius-sm);
  padding: 0.85rem 1rem; color: var(--c-ink); font-weight: 600; box-shadow: var(--shadow-sm);
  transition: transform var(--t), box-shadow var(--t), border-color var(--t), color var(--t);
}
.related__card a:hover { transform: translateY(-3px); box-shadow: var(--shadow-md); border-color: var(--c-primary); color: var(--c-primary-strong); }
.related__arrow { color: var(--c-accent); font-weight: 700; transition: transform var(--t); }
.related__card a:hover .related__arrow { transform: translateX(3px); }

/* ---------- content index ---------- */
.content-index { display: grid; gap: var(--gap); }
.content-index__pillar { background: var(--c-surface); border: 1px solid var(--c-border); border-radius: var(--radius); padding: 1.5rem; box-shadow: var(--shadow-sm); border-left: 5px solid var(--c-primary); }
.content-index__pillar--2 { border-left-color: var(--c-accent); }
.content-index__pillar--3 { border-left-color: var(--c-violet); }
.content-index__title { font-size: var(--step-1); margin: 0 0 1rem; }
.content-index__list { list-style: none; margin: 0; padding: 0; display: grid; gap: 0.9rem; }
.content-index__guide { font-weight: 650; font-size: 1.02rem; }
.content-index__sub { list-style: none; margin: 0.4rem 0 0; padding-left: 1rem; border-left: 2px solid var(--c-border); display: grid; gap: 0.3rem; }
.content-index__sub a { color: var(--c-ink-soft); font-size: 0.94rem; }
.content-index__sub a:hover { color: var(--c-primary-strong); }
@media (min-width: 880px) { .content-index { grid-template-columns: repeat(3, 1fr); align-items: start; } }

/* ---------- footer ---------- */
.site-footer { flex-shrink: 0; background: #14233b; color: #c7d4e6; margin-top: 3rem; }
.site-footer a { color: #c7d4e6; }
.site-footer a:hover { color: #fff; }
.site-footer__inner { display: grid; gap: 2rem; padding-block: 2.6rem; grid-template-columns: 1fr; }
.brand--footer .brand__name { color: #fff; }
.site-footer__tagline { color: #93a3bd; max-width: 46ch; margin: 0.8rem 0 0; font-size: 0.92rem; }
.site-footer__heading { font-size: 0.8rem; text-transform: uppercase; letter-spacing: 0.12em; color: #7f90ad; margin: 0 0 0.8rem; }
.site-footer__nav ul { list-style: none; margin: 0; padding: 0; display: grid; gap: 0.5rem; }
.site-footer__bar { border-top: 1px solid rgba(255, 255, 255, 0.08); font-size: 0.84rem; color: #7f90ad; }
.site-footer__bar p { margin: 0; padding-block: 1rem; }
@media (min-width: 760px) { .site-footer__inner { grid-template-columns: 1.6fr 1fr; } }

/* ---------- responsive nav ---------- */
@media (max-width: 960px) {
  .nav-toggle { display: inline-block; }
  .primary-nav {
    position: absolute; inset: var(--header-h) 0 auto 0; background: var(--c-surface);
    border-bottom: 1px solid var(--c-border); box-shadow: var(--shadow-md);
    max-height: 0; overflow: hidden; transition: max-height var(--t);
  }
  .primary-nav.is-open { max-height: 60vh; }
  .primary-nav__list { flex-direction: column; padding: 0.8rem; gap: 0.3rem; }
  .nav-link { width: 100%; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: 0.001ms !important; animation-iteration-count: 1 !important; transition-duration: 0.001ms !important; scroll-behavior: auto !important; }
}

/* ---------- zoomable diagrams + full-screen modal ---------- */
.mermaid.is-zoomable { position: relative; cursor: zoom-in; transition: box-shadow var(--t), border-color var(--t); }
.mermaid.is-zoomable:hover { border-color: var(--c-primary); box-shadow: var(--shadow-md); }
.mermaid.is-zoomable:focus-visible { box-shadow: var(--ring); }
.mermaid__expand {
  position: absolute; top: 8px; right: 8px; display: inline-flex; align-items: center; gap: 0.35rem;
  padding: 0.3rem 0.55rem; border: 1px solid var(--c-border-strong); border-radius: 8px;
  background: rgba(255, 255, 255, 0.9); color: var(--c-ink-soft); font-size: 0.74rem; font-weight: 600;
  cursor: zoom-in; opacity: 0; transform: translateY(-2px);
  transition: opacity var(--t), transform var(--t), background var(--t), color var(--t); backdrop-filter: blur(4px);
}
.mermaid__expand svg { width: 14px; height: 14px; fill: none; stroke: currentColor; stroke-width: 2; stroke-linecap: round; stroke-linejoin: round; }
.mermaid.is-zoomable:hover .mermaid__expand,
.mermaid.is-zoomable:focus-within .mermaid__expand,
.mermaid__expand:focus-visible { opacity: 1; transform: translateY(0); }
.mermaid__expand:hover { background: var(--c-primary); color: #fff; border-color: var(--c-primary); }
@media (hover: none) { .mermaid__expand { opacity: 1; transform: none; } }

body.modal-open { overflow: hidden; }
.diagram-modal { position: fixed; inset: 0; z-index: 1000; display: flex; align-items: center; justify-content: center; padding: clamp(0.5rem, 2vw, 2rem); }
.diagram-modal[hidden] { display: none; }
.diagram-modal__backdrop { position: absolute; inset: 0; background: rgba(16, 28, 48, 0.66); backdrop-filter: blur(3px); animation: modalFade var(--t); }
.diagram-modal__inner {
  position: relative; display: flex; flex-direction: column; background: var(--c-surface);
  border-radius: var(--radius); box-shadow: var(--shadow-lg); width: min(96vw, 1500px); max-height: 94vh;
  overflow: hidden; animation: modalPop 200ms cubic-bezier(0.2, 0.8, 0.2, 1);
}
.diagram-modal__bar { display: flex; align-items: center; justify-content: space-between; gap: 1rem; padding: 0.6rem 0.8rem 0.6rem 1.1rem; border-bottom: 1px solid var(--c-border); background: var(--c-surface-2); }
.diagram-modal__hint { font-size: 0.8rem; color: var(--c-muted); }
.diagram-modal__close { width: 34px; height: 34px; flex: none; border: 1px solid var(--c-border-strong); background: var(--c-surface); border-radius: 9px; font-size: 1.4rem; line-height: 1; color: var(--c-ink-soft); cursor: pointer; transition: background var(--t), color var(--t), border-color var(--t); }
.diagram-modal__close:hover { background: var(--c-coral); color: #fff; border-color: var(--c-coral); }
.diagram-modal__stage { padding: clamp(1rem, 3vw, 2.5rem); overflow: auto; display: flex; align-items: center; justify-content: center; }
.diagram-modal__svg { width: 100%; height: auto; max-width: none; }
@keyframes modalFade { from { opacity: 0; } to { opacity: 1; } }
@keyframes modalPop { from { opacity: 0; transform: scale(0.96); } to { opacity: 1; transform: scale(1); } }