/* RADevo public pages: revision topics and guides (9 Oct 2026). Same look as the home page. */
*, *::before, *::after { box-sizing:border-box; }
:root { --navy:#0B122B; --blue:#2563EB; --blue-d:#1D4ED8; --purple:#7C3AED; --pink:#EC4899; --orange:#F97316; --surface:#F8F9FF; --border:#E5E9F5; --muted:#5B6478; --text:#0B122B; --green:#047857; --red:#B91C1C; }
html { -webkit-text-size-adjust:100%; }
body { margin:0; background:#fff; color:var(--text); font:400 16px/1.65 'Poppins', system-ui, -apple-system, 'Segoe UI', sans-serif; }
a { color:var(--blue-d); }
a:hover { color:var(--purple); }
img { max-width:100%; height:auto; }
.skip { position:absolute; left:8px; top:-60px; background:var(--navy); color:#fff; padding:10px 16px; border-radius:8px; z-index:1000; font-weight:700; }
.skip:focus { top:8px; }

/* Header */
.site-nav { background:var(--navy); position:sticky; top:0; z-index:100; box-shadow:0 2px 20px rgba(0,0,0,.25); }
/* 9 Oct: full width like the home page, so the logo sits in the same place on every page */
.site-nav .in { padding:0 40px; height:68px; display:flex; align-items:center; gap:14px; }
.site-nav .logo { display:flex; align-items:center; color:#fff; text-decoration:none; font-weight:800; font-size:22px; letter-spacing:.12em; }
.site-nav .logo img { height:46px; width:auto; }
.site-nav .tagline { font-size:13px; font-weight:600; white-space:nowrap; }
.site-nav .tagline span:nth-child(1) { color:#60A5FA; }
.site-nav .tagline span:nth-child(2) { color:#F97316; }
.site-nav .tagline span:nth-child(3) { color:#A78BFA; }
.site-nav nav { margin-left:auto; }
@media (max-width:1320px) { .site-nav .in { padding:0 24px; } }
@media (max-width:900px) { .site-nav .tagline { display:none; } }
.site-nav nav { display:flex; align-items:center; gap:4px; flex-wrap:wrap; }
.site-nav nav a { color:rgba(255,255,255,.8); text-decoration:none; font-size:14px; font-weight:500; padding:6px 12px; border-radius:8px; }
.site-nav nav a:hover, .site-nav nav a[aria-current="page"] { color:#fff; background:rgba(255,255,255,.1); }
.site-nav nav a.btn { background:#fff; color:var(--navy); font-weight:700; }
.site-nav nav a.btn:hover { background:var(--surface); }
.stripe { height:3px; background:linear-gradient(90deg,var(--blue),var(--purple),var(--pink),var(--orange)); }
@media (max-width:700px) {
  .site-nav { position:static; }
  .site-nav .in { height:auto; padding:10px 16px; flex-wrap:wrap; }
  .site-nav nav { width:100%; justify-content:flex-start; gap:2px; }
  .site-nav nav a { padding:6px 9px; font-size:13px; }
  .site-nav nav a.hide-sm { display:none; }
}

/* Page */
main { max-width:1120px; margin:0 auto; padding:24px 20px 56px; }
.crumbs { font-size:13px; color:var(--muted); margin:0 0 14px; }
.crumbs ol { list-style:none; padding:0; margin:0; display:flex; flex-wrap:wrap; gap:4px; }
.crumbs li + li::before { content:"›"; margin:0 6px 0 2px; color:#9AA3B8; }
.crumbs a { color:var(--muted); text-decoration:none; }
.crumbs a:hover { color:var(--blue-d); text-decoration:underline; }
.eyebrow { display:inline-block; font-size:12px; font-weight:700; letter-spacing:.1em; text-transform:uppercase; color:var(--purple); margin-bottom:6px; }
h1 { font-size:clamp(26px,4.2vw,40px); line-height:1.15; letter-spacing:-.02em; margin:0 0 12px; font-weight:800; }
h2 { font-size:clamp(20px,2.8vw,26px); line-height:1.25; margin:40px 0 12px; font-weight:800; }
h3 { font-size:18px; margin:24px 0 8px; font-weight:700; }
.lead { font-size:18px; color:#323B52; max-width:760px; margin:0 0 8px; }
.meta { font-size:14px; color:var(--muted); }
p, li { max-width:760px; }

/* Cards and grids */
.grid { display:grid; grid-template-columns:repeat(auto-fill,minmax(260px,1fr)); gap:14px; margin:12px 0 8px; padding:0; list-style:none; }
.card { display:block; background:#fff; border:1px solid var(--border); border-radius:14px; padding:16px 18px; text-decoration:none; color:var(--text); transition:border-color .15s, box-shadow .15s, transform .15s; max-width:none; }
a.card:hover { border-color:var(--blue); box-shadow:0 6px 18px rgba(37,99,235,.10); transform:translateY(-1px); color:var(--text); }
.card .t { font-weight:700; line-height:1.3; display:block; }
.card .s { font-size:13px; color:var(--muted); display:block; margin-top:6px; }
.level { margin-top:28px; }
.level h2 { margin-top:24px; }

/* Practice questions */
.practice { background:var(--surface); border:1px solid var(--border); border-radius:18px; padding:20px; margin:16px 0; }
.practice .top { display:flex; justify-content:space-between; align-items:center; gap:10px; flex-wrap:wrap; margin-bottom:8px; }
.practice .score { font-weight:700; font-size:14px; color:var(--muted); }
.q { background:#fff; border:1px solid var(--border); border-radius:14px; padding:16px; margin:12px 0; max-width:none; }
.q .n { font-size:12px; font-weight:700; letter-spacing:.06em; text-transform:uppercase; color:var(--muted); }
.q .stem { font-weight:600; margin:4px 0 10px; }
.q .opts { display:grid; gap:8px; grid-template-columns:repeat(auto-fit,minmax(220px,1fr)); }
.q button.opt { font:inherit; font-size:15px; text-align:left; background:#fff; border:1.5px solid #C9D6F2; border-radius:10px; padding:10px 12px; min-height:46px; cursor:pointer; color:var(--text); }
.q button.opt:hover:not(:disabled) { border-color:var(--blue); }
.q button.opt:focus-visible { outline:3px solid #93C5FD; outline-offset:2px; }
.q button.opt:disabled { cursor:default; }
.q button.opt.right { background:#ECFDF5; border-color:#059669; color:#065F46; font-weight:600; }
.q button.opt.wrong { background:#FEF2F2; border-color:#DC2626; color:#991B1B; }
.q .fb { margin-top:10px; font-size:14px; font-weight:600; min-height:1em; }
.q .fb.ok { color:var(--green); }
.q .fb.no { color:var(--red); }
.done { display:none; margin-top:14px; background:#fff; border:1px solid var(--border); border-radius:14px; padding:16px; }
.done.show { display:block; }
.done b { font-size:18px; }

/* Key terms */
dl.terms { display:grid; grid-template-columns:minmax(140px,220px) 1fr; gap:0; border:1px solid var(--border); border-radius:14px; overflow:hidden; margin:12px 0; max-width:900px; }
dl.terms dt, dl.terms dd { margin:0; padding:10px 14px; border-top:1px solid var(--border); }
dl.terms dt:first-of-type, dl.terms dt:first-of-type + dd { border-top:none; }
dl.terms dt { font-weight:700; background:var(--surface); }
@media (max-width:600px) { dl.terms { grid-template-columns:1fr; } dl.terms dd { border-top:none; padding-top:0; } dl.terms dt { border-top:1px solid var(--border); } }

ul.subs { padding-left:20px; }
ul.subs li { margin:4px 0; }

/* Call to action */
.cta { display:grid; grid-template-columns:1fr 1fr; gap:14px; margin:28px 0 8px; }
.cta > div { border-radius:16px; padding:18px 20px; }
.cta .teach { background:linear-gradient(135deg,#0B122B,#1a2547); color:#fff; }
.cta .teach p { color:rgba(255,255,255,.85); }
.cta .stud { background:var(--surface); border:1px solid var(--border); }
.cta h2 { margin:0 0 6px; font-size:19px; }
.cta p { margin:0 0 12px; font-size:15px; }
.btn { display:inline-block; text-decoration:none; font-weight:700; font-size:15px; padding:10px 18px; border-radius:10px; }
.btn.primary { background:linear-gradient(135deg,var(--blue),var(--purple)); color:#fff; }
.btn.primary:hover { color:#fff; opacity:.9; }
.btn.ghost { background:#fff; color:var(--navy); border:1.5px solid #C9D6F2; }
@media (max-width:760px) { .cta { grid-template-columns:1fr; } }

.pager { display:flex; justify-content:space-between; gap:12px; flex-wrap:wrap; margin:28px 0 0; padding-top:18px; border-top:1px solid var(--border); }
.pager a { text-decoration:none; font-weight:600; max-width:48%; }

/* Articles */
article { max-width:760px; }
article p, article li { font-size:17px; }
article h2 { margin-top:36px; }
article blockquote { margin:16px 0; padding:12px 18px; border-left:4px solid var(--purple); background:var(--surface); border-radius:0 12px 12px 0; }
article table { border-collapse:collapse; width:100%; margin:12px 0; font-size:15px; }
article th, article td { border:1px solid var(--border); padding:8px 10px; text-align:left; vertical-align:top; }
article th { background:var(--surface); }
.table-wrap { overflow-x:auto; }
.refs { font-size:14px; color:var(--muted); }
.refs li { margin:4px 0; }

/* Footer */
footer.site { background:#0B122B; color:rgba(255,255,255,.55); padding:40px 20px; text-align:center; font-size:13px; line-height:1.6; }
footer.site a { color:rgba(255,255,255,.55); text-decoration:none; }
footer.site a:hover { color:#fff; }
footer.site p { max-width:none; margin:0 0 8px; color:rgba(255,255,255,.55); font-size:13px; }
footer.site .f-logo { height:40px; width:auto; display:block; margin:0 auto 16px; opacity:.7; }
footer.site .f-social { display:flex; justify-content:center; gap:16px; margin-bottom:16px; }
footer.site .f-social a { opacity:.6; transition:opacity .15s; color:#fff; }
footer.site .f-social a:hover { opacity:1; }
footer.site .f-small { margin-top:12px; font-size:11px; opacity:.5; }