/* ---------- the free reference pages (tools/seo/seo.mjs): memory items, limitations, abbreviations, the question of
   the day's archive, the systems and their sample questions. The photo hero is the Articles page's (.page-hero.has-photo);
   the end card is the Company page's (.ab-cta). ---------- */
.rf-hero .h1 { max-width: 18ch; margin-top: 14px; }
.rf-hero .lede { margin-top: 18px; }
.rf-hero .ph-photo::after { background: linear-gradient(90deg, rgba(11, 12, 14, 0.94) 0%, rgba(11, 12, 14, 0.84) 45%, rgba(11, 12, 14, 0.45) 80%, rgba(11, 12, 14, 0.4) 100%),
    linear-gradient(180deg, rgba(11, 12, 14, 0.5) 0%, rgba(11, 12, 14, 0) 28%, rgba(11, 12, 14, 0) 62%, rgba(11, 12, 14, 0.45) 100%); }
.rf-lit { display: inline-flex; align-items: center; gap: 10px; color: #3FE07F; margin-top: 22px; }
.rf-lit::before { content: ""; width: 6px; height: 6px; border-radius: 50%; background: currentColor; box-shadow: 0 0 10px currentColor; }
.rf-cta { margin-top: clamp(24px, 3vw, 32px); }
.rf-hero .btn-primary, .rf-hero .btn-ghost { --pb-bg: #F2F3F5; --pb-fg: #121315; }
.rf-crumbs ol { display: flex; flex-wrap: wrap; gap: 4px 0; list-style: none; margin: 0; padding: 0; font-size: 0.8125rem; color: rgba(242, 243, 245, 0.66); }
.rf-crumbs li + li::before { content: "/"; margin: 0 10px; opacity: .5; }
.rf-crumbs a { color: inherit; text-decoration: none; }
.rf-crumbs a:hover { color: #FFFFFF; text-decoration: underline; text-underline-offset: 3px; }
.rf-crumbs [aria-current] { color: rgba(242, 243, 245, 0.9); }
.rf-body { padding-top: clamp(24px, 4vw, 48px); }
.rf-grid { display: grid; grid-template-columns: minmax(0, 220px) minmax(0, 1fr); gap: clamp(32px, 5vw, 72px); align-items: start; }
.rf-toc { position: sticky; top: calc(var(--header-h) + 24px); display: grid; gap: 14px; }
.rf-toc ol { list-style: none; margin: 0; padding: 0; display: grid; gap: 2px; border-left: 1px solid var(--line); }
.rf-toc a { display: block; padding: 7px 0 7px 16px; margin-left: -1px; border-left: 1px solid transparent; color: var(--fg-2); font-size: 0.875rem; line-height: 1.35; text-decoration: none; }
.rf-toc a:hover { color: var(--fg); border-left-color: var(--fg); }
.rf-main { display: grid; gap: clamp(28px, 3vw, 40px); min-width: 0; }
.rf-src { font-size: 0.8125rem; line-height: 1.6; color: var(--muted); max-width: 70ch; }
.rf-body > .wrap > .rf-src { margin-top: 32px; }
@media (max-width: 900px) {
  .rf-grid { grid-template-columns: minmax(0, 1fr); }
  .rf-toc { position: static; }
  .rf-toc ol { display: flex; flex-wrap: wrap; gap: 8px; border: 0; }
  .rf-toc a { padding: 7px 12px; margin: 0; border: 1px solid var(--line-strong); border-radius: 999px; font-size: 0.8125rem; }
}
.rf-more { padding-block: clamp(40px, 5vw, 64px); }
.rf-links { list-style: none; margin: 20px 0 0; padding: 0; display: grid; grid-template-columns: repeat(auto-fill, minmax(min(100%, 260px), 1fr)); gap: 12px; }
.rf-links a { position: relative; display: grid; align-content: start; gap: 6px; height: 100%; padding: 18px 48px 18px 20px; border: 1px solid var(--line); border-radius: var(--radius); background: var(--surface); color: var(--fg); text-decoration: none; transition: border-color .25s ease, transform .35s var(--ease-out); }
.rf-links a:hover { border-color: var(--line-strong); transform: translateY(-2px); }
.rf-links b { font-weight: 600; line-height: 1.3; }
.rf-links span:not(.arrow) { font-size: 0.875rem; color: var(--muted); line-height: 1.45; }
.rf-links .arrow { position: absolute; right: 20px; top: 20px; }
.rf-end { padding-top: clamp(24px, 4vw, 48px); }

/* a memory item: its number and title, the situation, the callout, the QRH box of actions under their conditions */
.mi { scroll-margin-top: calc(var(--header-h) + 20px); display: grid; gap: 14px; padding-bottom: clamp(28px, 3vw, 40px); border-bottom: 1px solid var(--line); }
.mi-head { display: flex; align-items: baseline; gap: 14px; }
.mi-n { color: var(--muted); font-size: 0.8125rem; }
.mi-head .h3 { font-size: clamp(1.125rem, 1rem + 0.5vw, 1.375rem); letter-spacing: 0.01em; }
.mi-when, .mi-after { color: var(--fg-2); line-height: 1.6; max-width: 72ch; }
.mi-when b, .mi-after b { color: var(--fg); }
.mi-call { display: flex; flex-wrap: wrap; align-items: baseline; gap: 4px 12px; }
.mi-call q { font-weight: 700; color: var(--fg); quotes: "\201C" "\201D"; }
.mi-call-if, .mi-var { font-size: 0.875rem; color: var(--muted); }
.mi-box { display: grid; gap: 2px; padding: 16px 18px; border: 1px solid var(--line-strong); border-radius: var(--radius-sm); background: var(--surface); max-width: 720px; }
.mi-if { padding-left: calc(var(--d, 0) * 18px); margin-top: 8px; font-size: 0.8125rem; font-weight: 600; color: var(--steel); line-height: 1.45; }
.mi-if:first-child { margin-top: 0; }
.mi-if::before { content: "\25CF"; margin-right: 8px; font-size: 0.625rem; vertical-align: 2px; }
.mi-line { display: flex; align-items: baseline; gap: 6px; padding-left: calc(var(--d, 0) * 18px); font-size: 0.9375rem; font-weight: 600; letter-spacing: 0.02em; line-height: 1.5; }
.mi-line.is-plain { display: block; font-weight: 500; letter-spacing: 0; }
.mi-it { min-width: 0; overflow-wrap: anywhere; }
.mi-lead { flex: 1 1 16px; min-width: 16px; border-bottom: 2px dotted currentColor; opacity: .3; transform: translateY(-4px); }
.mi-ac { flex: none; max-width: 55%; text-align: right; color: var(--fg); }
.mi-vers { margin: 0; padding-left: 18px; display: grid; gap: 6px; font-size: 0.875rem; color: var(--muted); line-height: 1.5; max-width: 72ch; }
.mi-vers b { color: var(--fg-2); font-weight: 600; }

/* the limitations: a row each, its words and reference beside its figure */
.lim-group { scroll-margin-top: calc(var(--header-h) + 20px); display: grid; gap: 12px; }
.lim-list { list-style: none; margin: 0; padding: 0; border-top: 1px solid var(--line); }
.lim { display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 6px 24px; align-items: baseline; padding: 14px 0; border-bottom: 1px solid var(--line); }
.lim-q { display: flex; flex-wrap: wrap; align-items: baseline; gap: 6px 10px; min-width: 0; }
.lim-q b { font-weight: 600; line-height: 1.4; }
.lim-note { flex-basis: 100%; font-size: 0.875rem; color: var(--fg-2); line-height: 1.5; }
.lim-q .sq-ref { flex-basis: 100%; }
.lim-a { font-size: 1.0625rem; font-weight: 700; text-align: right; white-space: nowrap; }
@media (max-width: 560px) {
  .lim { grid-template-columns: minmax(0, 1fr); }
  .lim-a { order: -1; text-align: left; white-space: normal; }
}

/* the abbreviations: find, the letters, then each letter's list */
.abbr-tools { position: sticky; top: var(--header-h); z-index: 5; display: grid; gap: 14px; padding-block: 14px; background: var(--bg); border-bottom: 1px solid var(--line); }
.abbr-tools .faq-search { margin-top: 0; }
.abbr-letters { display: flex; flex-wrap: wrap; gap: 4px; }
.abbr-letters a { min-width: 34px; padding: 6px 8px; border-radius: 8px; text-align: center; font-size: 0.8125rem; font-weight: 600; color: var(--fg-2); text-decoration: none; }
.abbr-letters a:hover { background: var(--surface-2); color: var(--fg); }
.abbr-list { display: grid; gap: 8px; margin-top: 24px; }
.abbr-group { scroll-margin-top: calc(var(--header-h) + 150px); display: grid; grid-template-columns: 64px minmax(0, 1fr); gap: 0 24px; padding: 18px 0; border-bottom: 1px solid var(--line); }
.abbr-l { font-size: 1.75rem; font-weight: 700; color: var(--muted); line-height: 1.1; }
.abbr-group dl { margin: 0; display: grid; grid-template-columns: repeat(auto-fill, minmax(min(100%, 340px), 1fr)); gap: 2px 32px; }
.abbr-row { display: grid; grid-template-columns: minmax(84px, auto) minmax(0, 1fr); gap: 12px; padding: 6px 0; }
.abbr-row dt { font-weight: 700; letter-spacing: 0.02em; overflow-wrap: anywhere; }
.abbr-row dd { margin: 0; color: var(--fg-2); line-height: 1.45; }
.abbr-none { padding: 24px 0; color: var(--muted); }
@media (max-width: 560px) { .abbr-group { grid-template-columns: minmax(0, 1fr); } .abbr-l { margin-bottom: 8px; } }

/* a sample question: its options, then the answer and the explanation (study.js marks the options on a tap) */
.sq-list, .qa-list { display: grid; gap: clamp(20px, 2.4vw, 28px); }
.sq-list > *, .qa-list > * { max-width: 860px; }
.sq { scroll-margin-top: calc(var(--header-h) + 20px); display: grid; gap: 16px; padding: clamp(20px, 3vw, 32px); border: 1px solid var(--line); border-radius: 20px; background: var(--surface); }
.sq-k { display: flex; flex-wrap: wrap; align-items: center; gap: 8px 12px; }
.sq-k:empty { display: none; }
.sq-n { font-size: 0.6875rem; font-weight: 700; letter-spacing: 0.22em; text-transform: uppercase; color: var(--muted); }
.sq-k a.chip { text-decoration: none; }
.sq-k a.chip:hover { color: var(--fg); border-color: var(--fg-2); }
.sq-q { font-size: clamp(1.0625rem, 1rem + 0.35vw, 1.25rem); font-weight: 600; line-height: 1.45; letter-spacing: -0.005em; text-wrap: pretty; }
.sq-opts { list-style: none; margin: 0; padding: 0; display: grid; gap: 8px; }
.sq-opts > li { display: flex; align-items: baseline; gap: 12px; padding: 12px 14px; border: 1px solid var(--line); border-radius: 12px; line-height: 1.45; }
.sq-opts > li:has(> .sq-opt) { padding: 0; border: 0; }
.sq-opt { display: flex; align-items: baseline; gap: 12px; width: 100%; min-height: 48px; padding: 12px 14px; border: 1px solid var(--line-strong); border-radius: 12px; background: transparent; text-align: left; line-height: 1.45; cursor: pointer; transition: border-color .2s ease, background-color .2s ease; }
.sq-opt:hover:not(:disabled) { border-color: var(--fg-2); background: var(--surface-2); }
.sq-opt:focus-visible { outline: 2px solid var(--fg); outline-offset: 2px; }
.sq-opt:disabled { cursor: default; color: inherit; }
.sq-l { flex: none; width: 24px; height: 24px; display: inline-grid; place-items: center; border-radius: 6px; border: 1px solid var(--line-strong); font-size: 0.75rem; font-weight: 700; color: var(--muted); transform: translateY(-1px); }
.sq-o { flex: 1; min-width: 0; }
.sq-v { flex: none; margin-left: auto; font-size: 0.6875rem; font-weight: 700; letter-spacing: 0.12em; text-transform: uppercase; }
.sq-v:empty { display: none; }
.sq-opts > li.is-right .sq-opt { border-color: var(--ok); background: var(--ok-soft); }
.sq-opts > li.is-right .sq-l, .sq-opts > li.is-right .sq-v { color: var(--ok); border-color: var(--ok); }
.sq-opts > li.is-wrong .sq-opt { border-color: var(--warn); background: var(--warn-soft); }
.sq-opts > li.is-wrong .sq-l, .sq-opts > li.is-wrong .sq-v { color: var(--warn); border-color: var(--warn); }
.sq-opts > li.is-dim .sq-opt { opacity: .55; }
.sq-ans > summary { display: inline-flex; align-items: center; gap: 10px; min-height: 44px; cursor: pointer; font-weight: 600; font-size: 0.9375rem; color: var(--fg-2); list-style: none; }
.sq-ans > summary::-webkit-details-marker { display: none; }
.sq-ans > summary::before { content: "+"; display: inline-grid; place-items: center; width: 24px; height: 24px; border-radius: 50%; border: 1px solid var(--line-strong); font-weight: 500; line-height: 1; }
.sq-ans[open] > summary::before { content: "\2212"; }
.sq-ans > summary:hover { color: var(--fg); }
.sq-ans-in { display: grid; gap: 10px; margin-top: 8px; padding: 16px 18px; border-left: 2px solid var(--ok); border-radius: 0 12px 12px 0; background: var(--ok-soft); }
.sq-a b { color: var(--ok); }
.sq-why { color: var(--fg-2); line-height: 1.6; }
.sq-note { font-size: 0.875rem; color: var(--muted); }
.sq-ref { font-size: 0.75rem; letter-spacing: 0.02em; color: var(--muted); line-height: 1.5; overflow-wrap: anywhere; }
.sq-more { display: grid; gap: 18px; padding: clamp(20px, 3vw, 28px); border: 1px dashed var(--line-strong); border-radius: 20px; }
.sq-more p { color: var(--fg-2); line-height: 1.6; max-width: 66ch; }
.sq-more b { color: var(--fg); }

/* the question of the day's archive: each day's date, then its question */
.qa-day { scroll-margin-top: calc(var(--header-h) + 20px); display: grid; gap: 12px; }
.qa-date { font-size: 0.8125rem; font-weight: 700; letter-spacing: 0.18em; text-transform: uppercase; color: var(--muted); }
.qa-empty { display: grid; gap: 20px; justify-items: start; padding: clamp(22px, 3vw, 32px); border: 1px dashed var(--line-strong); border-radius: 20px; }
.qa-empty p { color: var(--fg-2); line-height: 1.6; max-width: 62ch; }
.qa-empty b { color: var(--fg); }

/* the systems: a card each, and a page's way to the others */
.sys-grid { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(auto-fill, minmax(min(100%, 260px), 1fr)); gap: 12px; }
.sys-card { position: relative; display: grid; align-content: start; gap: 6px; height: 100%; padding: 20px 48px 20px 20px; border: 1px solid var(--line); border-radius: var(--radius); background: var(--surface); color: var(--fg); text-decoration: none; transition: border-color .25s ease, transform .35s var(--ease-out); }
.sys-card:hover { border-color: var(--line-strong); transform: translateY(-2px); }
.sys-card b { font-size: 1.0625rem; font-weight: 600; line-height: 1.3; }
.sys-code { font-size: 0.6875rem; letter-spacing: 0.14em; color: var(--muted); }
.sys-n { font-size: 0.8125rem; color: var(--muted); }
.sys-card .arrow { position: absolute; right: 20px; top: 22px; }
.sys-chips { list-style: none; margin: 18px 0 0; padding: 0; display: flex; flex-wrap: wrap; gap: 8px; }
.sys-chips .chip { padding: 8px 12px; text-decoration: none; text-transform: none; letter-spacing: 0.01em; font-size: 0.8125rem; }
.sys-chips .chip:hover { color: var(--fg); border-color: var(--fg-2); }

@media (max-width: 560px) { .mi-if, .mi-line { padding-left: calc(var(--d, 0) * 12px); } .mi-box { padding: 14px; } }
@media (pointer: coarse) { .rf-crumbs a, .abbr-letters a { min-height: 44px; display: inline-flex; align-items: center; } }
.rf-hero .ph-photo img { filter: saturate(0.9) contrast(1.04) blur(0.6px); }
.sq-list > *, .qa-list > *, .qa-day > * { min-width: 0; }
.sq-q, .sq-o, .sq-why, .sq-a { overflow-wrap: anywhere; }

/* the systems (/a320-systems): each one's chapter, name, what it is, our videos on it and where to study it */
.sx-list { gap: 0; }
.sx { scroll-margin-top: calc(var(--header-h) + 20px); display: grid; gap: 12px; padding-block: clamp(22px, 2.6vw, 32px); border-bottom: 1px solid var(--line); }
.sx:first-child { padding-top: 0; }
.sx-k { display: flex; gap: 8px; }
.sx .h3 { font-size: clamp(1.125rem, 1rem + 0.5vw, 1.375rem); letter-spacing: 0.005em; }
.sx-p { color: var(--fg-2); line-height: 1.65; max-width: 72ch; }
.sx-v { list-style: none; margin: 0; padding: 0; display: grid; gap: 4px; font-size: 0.875rem; color: var(--muted); line-height: 1.45; }
.sx-v li::before { content: "\25B6"; margin-right: 10px; font-size: 0.5625rem; vertical-align: 2px; color: var(--steel); }
.sx-go { display: flex; flex-wrap: wrap; gap: 8px 22px; margin-top: 2px; }
.sx-go a { display: inline-flex; align-items: center; gap: 8px; font-size: 0.9375rem; font-weight: 600; color: var(--fg); text-decoration: none; }
.sx-go a:hover { color: var(--ok); }
.sx-go a .arrow { transition: transform .3s var(--ease-out); }
.sx-go a:hover .arrow { transform: translateX(3px); }