/* The site's shared look: fonts, colour tokens (light, dark, and the saved theme choice), base
   text, masthead, navigation, document text, tables, cards, buttons, footer, breadcrumbs and the
   previous/next pager. Linked by every page except public/app.html, which still carries an inline
   copy in its <style> until it is extracted too (rule 13 in .kiro/steering/engineering-guidelines.md).
   The study guide's pages also link public/guide.css, for what is theirs alone. The two copies are named
   duplication (rule 3): the @font-face rules, the colour tokens and the button rules (between the
   button-rules markers) here must equal app.html's, and tools/verify.mjs ("site.css and js/theme.js match
   public/app.html") fails when they don't. Change app.html first, then here. Contrast is measured on
   app.html's tokens, so equality covers this file. */
@font-face{font-family:'Inter Fallback';src:local('Arial'),local('Helvetica'),local('Liberation Sans');size-adjust:107.06%;ascent-override:90.49%;descent-override:22.56%;line-gap-override:0%;}
@font-face{font-family:'Space Grotesk';font-style:normal;font-weight:400 700;font-display:swap;src:url('/fonts/space-grotesk-latin-ext.woff2') format('woff2');unicode-range:U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+0304, U+0308, U+0329, U+1D00-1DBF, U+1E00-1E9F, U+1EF2-1EFF, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F, U+A720-A7FF;}
@font-face{font-family:'Space Grotesk';font-style:normal;font-weight:400 700;font-display:swap;src:url('/fonts/space-grotesk-latin.woff2') format('woff2');unicode-range:U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;}
@font-face{font-family:'Inter';font-style:normal;font-weight:400 700;font-display:swap;src:url('/fonts/inter-latin-ext.woff2') format('woff2');unicode-range:U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+0304, U+0308, U+0329, U+1D00-1DBF, U+1E00-1E9F, U+1EF2-1EFF, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F, U+A720-A7FF;}
@font-face{font-family:'Inter';font-style:normal;font-weight:400 700;font-display:swap;src:url('/fonts/inter-latin.woff2') format('woff2');unicode-range:U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;}
@font-face{font-family:'IBM Plex Mono';font-style:normal;font-weight:400;font-display:swap;src:url('/fonts/ibm-plex-mono-400-latin-ext.woff2') format('woff2');unicode-range:U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+0304, U+0308, U+0329, U+1D00-1DBF, U+1E00-1E9F, U+1EF2-1EFF, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F, U+A720-A7FF;}
@font-face{font-family:'IBM Plex Mono';font-style:normal;font-weight:400;font-display:swap;src:url('/fonts/ibm-plex-mono-400-latin.woff2') format('woff2');unicode-range:U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;}
@font-face{font-family:'IBM Plex Mono';font-style:normal;font-weight:500;font-display:swap;src:url('/fonts/ibm-plex-mono-500-latin-ext.woff2') format('woff2');unicode-range:U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+0304, U+0308, U+0329, U+1D00-1DBF, U+1E00-1E9F, U+1EF2-1EFF, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F, U+A720-A7FF;}
@font-face{font-family:'IBM Plex Mono';font-style:normal;font-weight:500;font-display:swap;src:url('/fonts/ibm-plex-mono-500-latin.woff2') format('woff2');unicode-range:U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;}

:root{
  --ink:#F2F0EB; --panel:#FFFFFF; --panel-2:#EAE7E0;
  --line: rgba(60,50,40,0.09); --line-strong: rgba(60,50,40,0.16);
  --cyan:#096677; --cyan-dim: rgba(10,110,128,0.10);
  --paper:#13313B; --paper-dim:#4F5D63;
  --green:#176B3A; --green-dim: rgba(30,127,70,0.12);
  --red:#A63C27; --red-dim: rgba(184,67,43,0.10);
  --amber:#80540D; --amber-dim: rgba(138,90,14,0.12);
  --on-accent:#FFFFFF; --shadow: rgba(60,50,40,0.10);
  --radius:8px;
  --font-display:'Space Grotesk', system-ui, sans-serif;
  --font-body:'Inter', 'Inter Fallback', system-ui, sans-serif;
  --font-mono:'IBM Plex Mono', ui-monospace, monospace;
  box-sizing:border-box; padding-top:env(safe-area-inset-top, 0px); padding-bottom:env(safe-area-inset-bottom, 0px);
}
/* Dark theme (6 Oct 2026): neutral greys, not the navy it used to be, so it reads as a true dark theme.
   Surfaces step up in lightness as they rise (page, panel, panel-2), lines are the text colour at low
   opacity, and the accents are the light theme's hues, lifted to stay at least 4.5:1 on every surface. */
@media (prefers-color-scheme: dark){ :root:not([data-theme="light"]){ --ink:#1C1E21; --panel:#27292E; --panel-2:#31343A;
  --line: rgba(233,234,236,0.10); --line-strong: rgba(233,234,236,0.20);
  --cyan:#6FD6E8; --cyan-dim: rgba(111,214,232,0.14);
  --paper:#E9EAEC; --paper-dim:#B7BBC3;
  --green:#7FD99A; --green-dim: rgba(127,217,154,0.14);
  --red:#F5A592; --red-dim: rgba(245,165,146,0.14);
  --amber:#E8B15E; --amber-dim: rgba(232,177,94,0.14);
  --on-accent:#1C1E21; --shadow: rgba(0,0,0,0.50); } }
:root[data-theme="dark"]{ --ink:#1C1E21; --panel:#27292E; --panel-2:#31343A;
  --line: rgba(233,234,236,0.10); --line-strong: rgba(233,234,236,0.20);
  --cyan:#6FD6E8; --cyan-dim: rgba(111,214,232,0.14);
  --paper:#E9EAEC; --paper-dim:#B7BBC3;
  --green:#7FD99A; --green-dim: rgba(127,217,154,0.14);
  --red:#F5A592; --red-dim: rgba(245,165,146,0.14);
  --amber:#E8B15E; --amber-dim: rgba(232,177,94,0.14);
  --on-accent:#1C1E21; --shadow: rgba(0,0,0,0.50); }
html{scroll-padding-top:env(safe-area-inset-top, 0px); scroll-behavior:smooth;}
*{box-sizing:border-box;}
html,body{margin:0;padding:0;}
body{background:var(--ink); color:var(--paper); font-family:var(--font-body); min-height:100vh; -webkit-font-smoothing:antialiased;}
button{font:inherit;}
:focus-visible{outline:2px solid var(--cyan); outline-offset:2px;}
.app{max-width:1180px; margin:0 auto; padding:28px 20px 80px;}
.masthead{display:flex; align-items:baseline; justify-content:space-between; gap:16px; flex-wrap:wrap;
  border-bottom:1px solid var(--line-strong); padding-bottom:16px; margin-bottom:28px;}
.masthead .brand{display:flex; align-items:center; gap:10px;}
.masthead .brand-mark{width:30px; height:30px; flex:none;}
.masthead .tagline{margin:4px 0 0; font-size:13px; color:var(--paper-dim);}
.nw{white-space:nowrap;}
.site-nav{display:flex; gap:4px; flex-wrap:wrap; margin:-12px 0 26px; border-bottom:1px solid var(--line);}
.site-nav a{font-family:var(--font-display); font-weight:500; font-size:14px; color:var(--paper-dim); text-decoration:none;
  padding:9px 12px; border-bottom:2px solid transparent; margin-bottom:-1px;}
.site-nav a:hover{color:var(--paper);}
.site-nav a.active{color:var(--cyan); border-bottom-color:var(--cyan);}
.mast-right{display:flex; align-items:center; gap:14px;}
.acct-link{font-family:var(--font-mono); font-size:12px; color:var(--cyan); text-decoration:none; border:1px solid var(--line-strong); border-radius:var(--radius); padding:5px 10px; white-space:nowrap;}
.acct-link:hover{border-color:var(--cyan);}
.theme-btn{font-family:var(--font-mono); font-size:12px; background:transparent; color:var(--paper-dim);
  border:1px solid var(--line-strong); border-radius:var(--radius); padding:5px 10px; cursor:pointer;}
.doc{max-width:860px; line-height:1.62; font-size:15px;}
.doc .lede{color:var(--paper-dim);}
.doc h1{font-family:var(--font-display); font-size:26px; line-height:1.25; margin:0 0 14px;}
.doc h2{font-family:var(--font-display); font-size:19px; line-height:1.3; margin:34px 0 10px; padding-top:10px; border-top:1px solid var(--line);}
.doc h3{font-family:var(--font-display); font-size:16px; line-height:1.3; margin:24px 0 8px;}
.doc p, .doc li{color:var(--paper);} .doc a{color:var(--cyan);}
.doc code{font-family:var(--font-mono); font-size:13px; background:var(--panel-2); padding:1px 5px; border-radius:var(--radius);}
.table-wrap{overflow-x:auto; margin:12px 0 18px;}
.doc table, .data-table{border-collapse:collapse; font-size:14px; min-width:100%;}
.doc th, .doc td, .data-table th, .data-table td{border:1px solid var(--line-strong); padding:8px 10px; text-align:left; vertical-align:top;}
.doc th, .data-table th{background:var(--panel-2); font-family:var(--font-display); font-weight:600;}
.card{background:var(--panel); border:1px solid var(--line-strong); border-radius:var(--radius); padding:20px;}
/* button-rules: the site's buttons. This block is the same, byte for byte, in public/site.css and public/app.html
   (checkSharedLookMatchesApp in tools/verify.mjs); change app.html first, then copy the block to site.css. Two roles in
   one colour, var(--cyan): .btn (filled) is the main action on a screen, and .btn.secondary (outlined) is every other
   button. No .btn takes any other colour, anywhere. Sizes: the default for an action that stands on the page,
   .btn.small inside a form, a toolbar or a card. A link styled as a button (a.btn) keeps its role's colour in every
   link state, ahead of a page's own link colour (.doc a, .landing a); keyboard focus is the :focus-visible outline
   every element has. Choices (timing chips, exam and mode cards, answer options) are not buttons, and keep rules of
   their own. */
.btn{font-family:var(--font-display); font-weight:600; font-size:14px; padding:12px 22px; border-radius:var(--radius);
  border:1px solid var(--cyan); background:var(--cyan); color:var(--on-accent); cursor:pointer; transition:opacity .15s;}
.btn:hover{opacity:0.88;}
.btn:disabled{opacity:0.35; cursor:not-allowed;}
.btn.secondary{background:transparent; color:var(--cyan);}
.btn.small{padding:8px 14px; font-size:13px;}
a.btn{display:inline-block; text-decoration:none;}
a.btn:link, a.btn:visited{color:var(--on-accent);}
a.btn.secondary:link, a.btn.secondary:visited{color:var(--cyan);}
/* /button-rules */
/* A row of buttons, on every page but the app (which lays its buttons out in its own rows). On a phone each
   button takes the full width. */
.cta-row{display:flex; flex-wrap:wrap; gap:10px; margin:0;}
@media (max-width:480px){ .cta-row .btn{flex:1 1 100%; text-align:center;} }
footer.disclaimer{margin-top:50px; padding-top:18px; border-top:1px solid var(--line); font-family:var(--font-mono);
  font-size:11px; color:var(--paper-dim); line-height:1.6;}
/* The Buy Me a Coffee line (PRODUCT-IDEAS.md item 41): a plain link, no widget or script, so nothing loads or tracks
   until someone clicks. */
footer.disclaimer .coffee{font-size:13px; margin:12px 0 0;}
/* In public/app.html the wordmark is the page heading; on these pages the heading is the page's own
   title, so the wordmark is a link styled the same way. */
.masthead .brand{text-decoration:none; color:inherit;}
.masthead .wordmark{font-family:var(--font-display); font-weight:700; font-size:22px;}
.masthead .wordmark span{color:var(--cyan);}
/* Breadcrumbs and the previous/next pager, on the study guide's pages (and any page with a place in a
   sequence). The breadcrumb separator is a chevron drawn with a rotated border, so it has no text to read
   aloud. */
.crumbs ol{list-style:none; margin:0 0 10px; padding:0; display:flex; flex-wrap:wrap; align-items:center;
  font-size:13px;}
.crumbs li + li::before{content:""; display:inline-block; width:.4em; height:.4em;
  border-right:1px solid currentColor; border-top:1px solid currentColor; transform:rotate(45deg);
  margin:0 .5em .1em .2em;}
.pager{display:flex; flex-wrap:wrap; justify-content:space-between; gap:8px 16px; margin:28px 0 0;
  padding-top:14px; border-top:1px solid var(--line); font-size:14px;}