:root {
  --bg: #f0f0f0; /* base-lightest */
  --surface: #ffffff;
  --surface-2: #f0f0f0;
  --paper: #ffffff;
  --ink: #1b1b1b; /* ink */
  --ink-2: #3d4551; /* base-darker */
  --ink-3: #565c65; /* base-dark */
  --line: #a9aeb1; /* base-light */
  --line-2: #dfe1e2; /* base-lighter */
  --primary: #005ea2; /* primary */
  --primary-dark: #1a4480; /* primary-dark */
  --primary-darker: #162e51; /* primary-darker */
  --primary-ink: #ffffff;
  --primary-soft: #d9e8f6; /* primary-lighter */
  --accent: #ffbe2e; /* gold */
  --ok: #00a91c; /* success */
  --ok-text: #008817; /* success-dark */
  --ok-soft: #ecf3ec; /* success-lighter */
  --warn: #ffbe2e; /* warning */
  --warn-text: #936f38; /* warning-darker */
  --warn-soft: #faf3d1; /* warning-lighter */
  --bad: #d54309; /* error */
  --bad-text: #b50909; /* error-dark */
  --bad-soft: #f4e3db; /* error-lighter */
  --info: #00bde3; /* info */
  --info-soft: #e7f6f8; /* info-lighter */
  --ins: #00702b; /* green-cool-60v-ish, readable on its tint */
  --ins-bg: #e3f5e1;
  --del: #b50909;
  --del-bg: #f8dfe2;
  --note: #fef0c8; /* yellow-5 */
  --note-strong: #e5a000; /* gold-30v */
  --focus: #2491ff; /* USWDS focus */
  --shadow: 0 1px 4px rgba(0, 0, 0, 0.1);
  --radius: 4px;
  --font: 'Public Sans', 'Source Sans Pro', 'Helvetica Neue', Helvetica, Roboto, Arial, sans-serif;
  --serif: Merriweather, Georgia, Cambria, 'Times New Roman', serif;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #111418;
    --surface: #1b1f24;
    --surface-2: #23282e;
    --paper: #1f2329;
    --ink: #f0f0f0;
    --ink-2: #dfe1e2;
    --ink-3: #a9aeb1;
    --line: #565c65;
    --line-2: #3d4551;
    --primary: #73b3e7; /* primary-light */
    --primary-dark: #4f97d1;
    --primary-darker: #162e51;
    --primary-ink: #0b1a2c;
    --primary-soft: #1e3352;
    --accent: #ffbe2e;
    --ok: #70e17b;
    --ok-text: #70e17b;
    --ok-soft: #1a3320;
    --warn: #ffbe2e;
    --warn-text: #ffd27a;
    --warn-soft: #3a2f12;
    --bad: #f39268;
    --bad-text: #ff8f80;
    --bad-soft: #3d1f17;
    --info: #00bde3;
    --info-soft: #10313a;
    --ins: #7fe08f;
    --ins-bg: #183623;
    --del: #ff9b94;
    --del-bg: #3d1d1f;
    --note: #4a3d0c;
    --note-strong: #c89b2a;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.5);
    color-scheme: dark;
  }
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body { background: var(--bg); color: var(--ink); font: 17px/1.6 var(--font); -webkit-font-smoothing: antialiased; }
a { color: var(--primary); } a:visited { color: #54278f; }
@media (prefers-color-scheme: dark) { a:visited { color: #b8a2e3; } }
:focus-visible { outline: 3px solid var(--focus); outline-offset: 2px; }
h1, h2, h3 { line-height: 1.25; margin: 1.6em 0 0.5em; }
h1 { font-size: 2rem; margin-top: 0.2em; } h2 { font-size: 1.35rem; } h3 { font-size: 1.1rem; }
p { margin: 0 0 0.85em; }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
.skip { position: absolute; left: -999px; top: 0; background: var(--surface); padding: 8px 12px; z-index: 100; }
.skip:focus { left: 8px; top: 8px; }
.topbar { display: flex; align-items: center; gap: 16px; padding: 0 24px; min-height: 60px; background: var(--primary-darker); color: #fff; border-bottom: 4px solid var(--accent); flex-wrap: wrap; }
.topbar a, .topbar a:visited { color: #fff; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 1.15rem; text-decoration: none; }
.topbar .spacer { flex: 1; }
.topbar .out { font-weight: 600; font-size: 0.95rem; }
.page { max-width: 820px; margin: 0 auto; padding: 32px 24px 48px; }
.foot { max-width: 820px; margin: 0 auto; padding: 16px 24px 40px; color: var(--ink-3); font-size: 0.85rem; border-top: 1px solid var(--line-2); }
.dim { color: var(--ink-3); }
.slate { display: flex; gap: 8px; flex-wrap: wrap; margin: 0; }
.slate span { font-size: 0.8rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.06em; background: var(--primary-soft); color: var(--ink); padding: 2px 8px; border-radius: 2px; }
.lede { font-size: 1.15rem; color: var(--ink-2); }
.ui { font-weight: 700; color: var(--ink); background: var(--surface-2); border: 1px solid var(--line-2); border-radius: 3px; padding: 0 5px; white-space: nowrap; font-size: 0.93em; }
.card { background: var(--surface); border: 1px solid var(--line-2); border-radius: var(--radius); padding: 16px 18px; box-shadow: var(--shadow); }
.alert { border-left: 8px solid var(--info); background: var(--info-soft); padding: 12px 16px; margin: 1rem 0; border-radius: 0 var(--radius) var(--radius) 0; }
.alert .t { display: block; margin-bottom: 4px; }
.alert p:last-child { margin-bottom: 0; }
.alert.warning { border-left-color: var(--warn); background: var(--warn-soft); }
.alert.success { border-left-color: var(--ok); background: var(--ok-soft); }
.alert.error { border-left-color: var(--bad); background: var(--bad-soft); }
.alert ul { margin: 0.4rem 0 0.8rem; }
.shot { margin: 1.4rem 0 1.8rem; }
.shot img { display: block; width: 100%; height: auto; border: 1px solid var(--line); border-radius: var(--radius); background: #fff; }
.shot figcaption { color: var(--ink-3); font-size: 0.92rem; margin-top: 0.5rem; }
.callouts { margin: 0.8rem 0 0; padding: 0; list-style: none; counter-reset: c; display: grid; gap: 0.45rem; }
.callouts li { counter-increment: c; position: relative; padding-left: 2.3rem; }
.callouts li::before { content: counter(c); position: absolute; left: 0; top: 0.05rem; width: 1.6rem; height: 1.6rem; border-radius: 50%;
  background: #162e51; color: #fff; box-shadow: 0 0 0 2px #ffbe2e; font-weight: 700; font-size: 0.85rem; display: grid; place-items: center; }
.steps { padding-left: 1.4rem; } .steps li { margin-bottom: 0.55rem; padding-left: 0.2rem; }
.q { margin: 1rem 0; } .qn { font-size: 0.75rem; font-weight: 700; letter-spacing: 0.1em; text-transform: uppercase; color: var(--ink-3); margin: 0 0 0.3rem; }
.choices { display: grid; gap: 8px; margin: 0.6rem 0; }
.q .choice { text-align: left; width: 100%; font: inherit; color: var(--ink); cursor: pointer; background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 10px 14px; }
.q .choice:hover { border-color: var(--primary); }
.q .choice[aria-pressed="true"].right { border: 2px solid var(--ok-text); }
.q .choice[aria-pressed="true"].wrong { border: 2px solid var(--bad-text); }
.fb { margin: 0.4rem 0 0; min-height: 1.2em; }
.fb.right { color: var(--ok-text); } .fb.wrong { color: var(--bad-text); }
.next { margin-top: 2rem; } .next b { text-transform: uppercase; letter-spacing: 0.08em; font-size: 0.8rem; color: var(--primary); } .next p { margin: 0.3rem 0 0; }
.tbl { overflow-x: auto; margin: 1rem 0 1.4rem; } .tbl table { border-collapse: collapse; width: 100%; font-size: 0.95rem; background: var(--surface); }
.tbl th, .tbl td { text-align: left; padding: 0.5rem 0.75rem; border: 1px solid var(--line-2); vertical-align: top; }
.tbl th { background: var(--surface-2); font-size: 0.9rem; }
.pager { display: flex; justify-content: space-between; gap: 1rem; margin: 2.4rem 0 0; padding-top: 1rem; border-top: 1px solid var(--line-2); flex-wrap: wrap; }
.pager a { font-weight: 600; }
.index { list-style: none; padding: 0; margin-top: 1.6rem; }
.index li { position: relative; margin: 0 0 0.9rem; padding: 0.9rem 1rem; background: var(--surface); border: 1px solid var(--line-2); border-left: 4px solid var(--primary); border-radius: var(--radius); }
.index li:hover, .index li:focus-within { border-color: var(--primary); background: var(--primary-soft); }
.index a { display: flex; gap: 1rem; align-items: baseline; flex-wrap: wrap; text-decoration: none; color: var(--ink); }
.index a::after { content: ""; position: absolute; inset: 0; }
.ix-n { font-size: 0.75rem; font-weight: 700; letter-spacing: 0.08em; text-transform: uppercase; color: var(--ink-3); min-width: 6rem; }
.ix-t { font-weight: 700; font-size: 1.1rem; flex: 1; } .ix-m { color: var(--ink-3); font-size: 0.9rem; }
.index p { margin: 0.3rem 0 0; color: var(--ink-2); }
.files { margin: 1.2rem 0; } .files ul { margin: 0.4rem 0 0; }
.btn { display: inline-flex; align-items: center; gap: 6px; border: 0; box-shadow: inset 0 0 0 2px var(--primary); background: transparent; color: var(--primary); border-radius: 4px; padding: 9px 18px; cursor: pointer; font-weight: 700; text-decoration: none; }
.btn.primary, .btn.primary:visited { background: var(--primary); color: var(--primary-ink); box-shadow: none; }
.btn.primary:hover { background: var(--primary-dark); }
.field { display: grid; gap: 4px; margin: 1rem 0; font-weight: 600; max-width: 520px; }
.field select, .field textarea { font: inherit; font-weight: 400; padding: 8px; border: 1px solid var(--ink-3); border-radius: 0; background: var(--surface); color: var(--ink); }
.drop { display: grid; place-items: center; gap: 4px; padding: 32px 16px; border: 2px dashed var(--line); border-radius: var(--radius); background: var(--surface); cursor: pointer; text-align: center; }
.drop.over, .drop:focus-within { border-color: var(--primary); background: var(--primary-soft); }
.drop span { color: var(--ink-3); }
.feedback fieldset { border: 0; padding: 0; margin: 0; } .feedback legend { font-weight: 600; margin-bottom: 6px; }
.rating { display: flex; gap: 16px; flex-wrap: wrap; }
@media (max-width: 600px) { .page { padding: 20px 16px 40px; } h1 { font-size: 1.6rem; } .topbar { padding: 8px 16px; } }