@font-face { font-family: "Literata"; src: url("fonts/literata-latin-variable.woff2") format("woff2"); font-style: normal; font-weight: 400 900; font-display: swap; }
@font-face { font-family: "Libre Franklin"; src: url("fonts/libre-franklin-latin-variable.woff2") format("woff2"); font-style: normal; font-weight: 100 900; font-display: swap; }
:root { --paper: #111820; --ink: #e7edf3; --muted: #a5b3c2; --blue: #86c5ff; --pale: #18232e; --line: #354350; --rule: #536577; --soft-line: #293745; --selected: #20374b; --button-ink: #111820; --button-hover: #add8ff; --active: #b6dcff; --selection: #314f69; --selection-ink: #f1f6fb; --gold: #cc9c42; --serif: "Literata", Georgia, serif; --sans: "Libre Franklin", Arial, sans-serif; --ease-out: cubic-bezier(0.23, 1, 0.32, 1); color-scheme: dark; color: var(--ink); background: var(--paper); font-family: var(--sans); font-synthesis: none; }
:root[data-theme="light"] { --paper: #fff; --ink: #161e28; --muted: #536171; --blue: #005899; --pale: #f2f6f9; --line: #c9d2d9; --rule: #83909b; --soft-line: #e1e6ea; --selected: #e8f2f9; --button-ink: #fff; --button-hover: #004676; --active: #003f6d; --selection: #d9eaf6; --selection-ink: #102d43; color-scheme: light; }
* { box-sizing: border-box; }
body { margin: 0; font-size: 18px; line-height: 1.65; }
a { color: var(--blue); text-underline-offset: .22em; }
a:hover { text-decoration-thickness: 2px; }
a:active { color: var(--active); }
:focus-visible { outline: 3px solid var(--blue); outline-offset: 4px; border-radius: 2px; }
::selection { background: var(--selection); color: var(--selection-ink); }
h1, h2, h3 { font-family: var(--serif); font-weight: 650; line-height: 1.2; text-wrap: balance; }
p { margin: 0 0 1em; }
.page-width { width: min(1200px, calc(100% - 96px)); margin-inline: auto; }
.skip-link { position: absolute; top: -100px; left: 24px; background: var(--paper); padding: 12px 20px; z-index: 10; }
.skip-link:focus { top: 8px; }
.site-header { min-height: 88px; display: flex; align-items: center; justify-content: space-between; gap: 28px; border-bottom: 1px solid var(--rule); }
.wordmark { font: 650 21px/1.25 var(--serif); color: var(--ink); text-decoration: none; letter-spacing: -.025em; }
.wordmark-dot { color: var(--blue); }
.header-nav { display: flex; gap: 32px; align-items: center; font-size: 14px; }
.header-nav a { color: var(--ink); text-decoration: none; padding: 17px 0; border-bottom: 2px solid transparent; }
.header-nav a:hover, .header-nav a[aria-current] { border-color: var(--gold); }
.theme-toggle { width: 44px; height: 44px; padding: 10px; display: inline-grid; place-items: center; font: inherit; color: var(--ink); background: var(--pale); border: 1px solid var(--line); border-radius: 5px; cursor: pointer; flex-shrink: 0; }
.theme-symbol { display: block; width: 20px; height: 20px; background: currentColor; mask: url("icons/sun.svg") center / contain no-repeat; }
:root[data-theme="light"] .theme-symbol { mask-image: url("icons/moon.svg"); }
@media (forced-colors: active) { .theme-symbol { background: ButtonText; forced-color-adjust: none; } }
.theme-toggle[hidden] { display: none; }
.theme-toggle:hover { border-color: var(--blue); }
.theme-toggle:active { background: var(--selected); }
.hero { padding-block: 70px 64px; }
.hero h1 { font-size: clamp(42px, 5.4vw, 76px); letter-spacing: -.035em; line-height: 1.13; margin: 0 0 36px; max-width: 1100px; }
.hero h1 span { color: var(--blue); }
.desktop-break { display: none; }
.hero-bottom { display: flex; align-items: center; justify-content: space-between; gap: 60px; }
.hero-copy { max-width: 640px; color: var(--muted); }
.hero-copy p { margin-bottom: 12px; }
.free-note { font-size: 14px; color: var(--muted); }
.hero-actions { display: flex; gap: 12px; flex-shrink: 0; }
.button { display: inline-flex; align-items: center; justify-content: center; min-height: 48px; padding: 11px 19px; border: 1px solid var(--blue); border-radius: 5px; font-weight: 550; font-size: 15px; line-height: 1.5; text-align: center; text-decoration: none; }
.primary { background: var(--blue); color: var(--button-ink); }
.primary:hover, .primary:active { background: var(--button-hover); color: var(--button-ink); }
.secondary { background: var(--paper); }
.secondary:hover { background: var(--pale); }
.task-directory { border-top: 1px solid var(--line); padding-top: 48px; }
.directory-heading { display: flex; align-items: baseline; justify-content: space-between; gap: 24px; }
.directory-heading h2 { font-size: 32px; margin: 0 0 12px; }
.directory-heading p { font-size: 16px; color: var(--muted); }
.directory-count { white-space: nowrap; font-size: 13px; color: var(--muted); }
.unit-jumps { display: grid; grid-template-columns: repeat(4, 1fr); border-block: 1px solid var(--line); margin-top: 24px; }
.unit-jumps a { padding: 17px 18px 17px 0; text-decoration: none; font-size: 14px; font-weight: 600; }
.unit-jumps a:hover { color: var(--ink); }
.unit-jumps span { display: block; color: var(--muted); font-size: 13px; font-weight: 400; line-height: 1.5; margin-top: 5px; max-width: 23ch; }
.sample-note { color: var(--muted); font-size: 13px; margin-top: 16px; }
.unit-section { display: grid; grid-template-columns: 280px 1fr; gap: 80px; padding-block: 44px; border-bottom: 1px solid var(--line); scroll-margin-top: 24px; }
.unit-number { font-size: 14px; color: var(--blue); font-weight: 600; }
.unit-intro h3 { font-size: 26px; margin: 10px 0 16px; }
.unit-intro p { font-size: 15px; color: var(--muted); }
.task-list { list-style: none; padding: 0; margin: 0; }
.task-list li + li { border-top: 1px solid var(--soft-line); }
.task-list a { display: grid; grid-template-columns: 28px 1fr auto; gap: 14px; padding: 17px 10px; color: var(--ink); text-decoration: none; border-radius: 4px; }
.task-list a:hover { background: var(--pale); }
.task-number { font-size: 13px; color: var(--muted); font-variant-numeric: tabular-nums; padding-top: 3px; }
.task-name { font-size: 16px; line-height: 1.55; }
.task-format { font-size: 12px; align-self: center; color: var(--blue); white-space: nowrap; }
.about-section { display: grid; grid-template-columns: 1fr 1.5fr; gap: 100px; padding-block: 68px; }
.about-section h2 { font-size: 32px; margin: 0; }
.about-section p { font-size: 16px; color: var(--muted); }
.text-link { font-size: 15px; }
.site-footer { padding-block: 32px 28px; border-top: 1px solid var(--rule); color: var(--muted); font-size: 13px; }
.footer-top { display: flex; align-items: center; justify-content: space-between; margin-bottom: 24px; gap: 24px; }
.footer-top > a:last-child { padding-block: 10px; }
.site-footer .wordmark { font-size: 18px; }
.legal { max-width: 95ch; font-size: 12px; margin-bottom: 0; }
.guide-layout { display: grid; grid-template-columns: 248px minmax(0, 1fr); gap: 74px; padding-block: 38px 68px; }
.desktop-task-nav { position: sticky; top: 24px; max-height: calc(100dvh - 48px); overflow-y: auto; align-self: start; padding: 0 14px 16px 0; }
.all-tasks-link { display: inline-block; margin: 0 0 20px; padding-block: 8px; font-size: 14px; }
.nav-unit { border-top: 1px solid var(--line); }
.nav-unit summary { cursor: pointer; padding: 16px 0; font-size: 13px; font-weight: 550; line-height: 1.5; }
.nav-unit summary > span { display: block; font-weight: 400; color: var(--muted); margin-bottom: 4px; }
.nav-unit ol { list-style: none; padding: 0; margin: 0 0 12px; }
.nav-unit li a { display: flex; gap: 12px; align-items: baseline; padding: 10px 8px; font-size: 13px; line-height: 1.5; text-decoration: none; color: var(--muted); border-radius: 5px; }
.nav-unit a:hover { background: var(--pale); color: var(--blue); }
.nav-unit a[aria-current] { background: var(--selected); color: var(--blue); font-weight: 550; }
.nav-number { font-size: 11px; min-width: 10px; font-variant-numeric: tabular-nums; }
.guide-main { min-width: 0; max-width: 760px; }
.breadcrumbs { display: flex; align-items: center; flex-wrap: wrap; gap: 12px; font-size: 12px; color: var(--muted); margin: 0 0 25px; }
.breadcrumbs a { padding-block: 7px; }
.guide-header h1 { font-size: clamp(32px, 3.1vw, 44px); letter-spacing: -.025em; margin: 0 0 20px; }
.guide-intro { font-size: 17px; color: var(--muted); }
.download { justify-content: space-between; gap: 20px; margin: 8px 0 22px; }
.download span { font-weight: 400; font-size: 12px; }
.article { line-height: 1.7; max-width: 65ch; }
.guide-section { margin-top: 34px; scroll-margin-top: 20px; }
.guide-section h2 { font-size: 25px; line-height: 1.3; margin: 0 0 16px; }
.guide-section p, .guide-section ul, .guide-section ol { margin: 0 0 17px; }
.guide-section li { margin-bottom: 8px; }
.guide-section ul, .guide-section ol { padding-left: 24px; }
.guide-section strong { font-weight: 600; }
.guide-section.example { background: var(--pale); border: 1px solid var(--line); border-radius: 14px; padding: 28px; margin-block: 38px; }
.guide-section.example h2 { color: var(--blue); }
.guide-section.checklist { border-block: 1px solid var(--line); padding-block: 25px 8px; }
.guide-section hr { border: 0; border-top: 1px solid var(--line); margin: 32px 0 20px; }
.guide-section:last-child p:last-child { font-size: 13px; color: var(--muted); }
.guide-pager { display: flex; justify-content: space-between; align-items: center; gap: 32px; border-top: 1px solid var(--line); padding-top: 25px; margin-top: 32px; font-size: 14px; }
.guide-pager a { padding-block: 10px; }
.guide-pager a:last-child { text-align: right; }
.guide-pager span { display: block; color: var(--muted); font-size: 12px; margin-top: 5px; }
.mobile-task-nav { display: none; }
.page-jumps { display: flex; flex-wrap: wrap; gap: 4px 24px; border-block: 1px solid var(--line); padding-block: 10px; margin-block: 12px 28px; font-size: 14px; }
.page-jumps a { padding-block: 8px; }
.learning-section, .calculator { border-top: 1px solid var(--line); padding-top: 32px; margin-top: 44px; scroll-margin-top: 24px; }
.learning-section h2, .calculator h2 { font-size: 28px; margin: 0 0 18px; }
.learning-section h3 { font: 600 20px/1.5 var(--sans); margin-block: 26px 16px; }
.section-note, .choice-help { color: var(--muted); font-size: 14px; }
.practice-choices { border-block: 1px solid var(--line); margin-block: 22px; }
.practice-choice + .practice-choice { border-top: 1px solid var(--line); }
.practice-choice summary, .example-stages summary { padding: 16px 8px; min-height: 48px; cursor: pointer; font-weight: 550; line-height: 1.55; }
.practice-choice summary:hover, .example-stages summary:hover { color: var(--blue); }
.practice-choice[open] { background: var(--pale); }
.choice-feedback { padding: 0 18px 6px; }
.choice-feedback p { font-size: 16px; }
.choice-feedback .answer-label { color: var(--blue); font-size: 13px; font-weight: 600; margin-bottom: 8px; }
.transfer { font-size: 16px; }
.worked-example { background: var(--pale); border: 1px solid var(--line); border-radius: 14px; padding: 28px; }
.example-stages { padding-left: 24px; margin: 24px 0 0; }
.example-stages li { padding-left: 5px; }
.example-stages li + li { border-top: 1px solid var(--line); }
.example-stages li::marker { color: var(--blue); font-variant-numeric: tabular-nums; }
.example-stages p { font-size: 16px; padding: 0 8px 6px; }
.tools-section { display: grid; grid-template-columns: 1fr 1.5fr; gap: 100px; padding-block: 50px; border-bottom: 1px solid var(--line); }
.tools-section h2 { font-size: 32px; margin: 0 0 20px; }
.tools-section p { font-size: 16px; color: var(--muted); }
.tools-section ul { list-style: none; padding: 0; margin: 0; }
.tools-section li + li { border-top: 1px solid var(--line); }
.tools-section li { padding-block: 16px; }
.tools-section li a { display: inline-block; padding-block: 6px; }
.tools-section li span { display: block; font-size: 14px; color: var(--muted); }
.tools-page { max-width: 820px; padding-block: 48px 68px; }
.tools-page h1 { font-size: clamp(36px, 4vw, 52px); }
.profile-page { max-width: 820px; padding-block: 40px 60px; }
.profile-page .guide-header h1 { font-size: clamp(36px, 4vw, 48px); }
.ready-pouch-note a { white-space: nowrap; }
.tool-link-list { list-style: none; padding: 0; margin: 26px 0; border-top: 1px solid var(--line); }
.tool-link-list li { border-bottom: 1px solid var(--line); padding-block: 16px; }
.tool-link-list a { display: inline-block; padding-block: 5px; font-weight: 550; }
.tool-link-list span { display: block; font-size: 14px; color: var(--muted); }
.calculator-page { max-width: 1060px; padding-block: 32px 60px; }
.calculator-header h1 { font-size: clamp(30px, 3.2vw, 42px); margin: 0 0 10px; letter-spacing: -.025em; }
.calculator-header p { margin-bottom: 14px; font-size: 16px; color: var(--muted); }
.calculator-switch { display: flex; flex-wrap: wrap; gap: 0 24px; border-block: 1px solid var(--line); margin-block: 16px 20px; font-size: 14px; }
.calculator-switch a { padding-block: 10px; text-decoration: none; border-bottom: 2px solid transparent; }
.calculator-switch a:hover, .calculator-switch a[aria-current] { border-bottom-color: var(--gold); color: var(--ink); }
.calculator { font-size: 16px; }
.calculator-page .calculator { border-top: 0; padding-top: 0; margin-top: 0; }
.calculator-workspace { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: 40px; align-items: start; margin-block: 20px 30px; }
.calculator-workspace[hidden] { display: none; }
.calculator-entry { min-width: 0; }
.calculator-fields { display: grid; grid-template-columns: 1fr; gap: 16px; margin: 0; }
.calculator-field { min-width: 0; }
.calculator-field label { display: block; font-size: 15px; font-weight: 550; margin-bottom: 8px; }
.calculator-field input { width: 100%; min-height: 48px; border: 1px solid var(--rule); border-radius: 5px; padding: 10px 12px; color: var(--ink); background: var(--paper); font: inherit; font-variant-numeric: tabular-nums; }
.calculator-field input[aria-invalid="true"] { border: 2px solid var(--blue); }
.calculator-error { color: var(--ink); font-size: 14px; margin-block: 8px 0; }
.calculator-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-block: 24px; }
.calculator-actions .button { cursor: pointer; font-family: var(--sans); }
.calculator-result { background: var(--pale); padding: 24px; border: 1px solid var(--line); border-radius: 14px; overflow-wrap: anywhere; font-variant-numeric: tabular-nums; }
.calculator-result h2 { font-size: 24px; margin: 0 0 16px; }
.calculator-result [data-result] { font-size: 15px; margin-bottom: 12px; }
.calculator-result dl { margin: 16px 0; }
.calculator-result dl > div { display: flex; align-items: baseline; justify-content: space-between; gap: 20px; border-top: 1px solid var(--line); padding-block: 12px; }
.calculator-result dt { font-size: 14px; min-width: 0; }
.calculator-result dd { font-size: 17px; font-weight: 600; margin: 0; text-align: right; min-width: 0; }
.calculator-result dl > .result-main { display: block; }
.calculator-result .result-main dd { font-size: clamp(28px, 3vw, 38px); line-height: 1.3; text-align: left; margin-top: 6px; color: var(--blue); }
.calculator-limit, .calculator-caption { font-size: 13px; color: var(--muted); }
.calculator-limit { margin: 16px 0 0; }
.calculator-help { border-bottom: 1px solid var(--line); }
.calculator-help summary { cursor: pointer; min-height: 48px; padding-block: 14px; font-weight: 550; }
.calculator-help summary:hover { color: var(--blue); }
.calculator-help p { font-size: 16px; max-width: 70ch; }
.calculator input, .calculator button { scroll-margin-block: 32px; }
.tool-return { border-top: 1px solid var(--line); margin-top: 38px; padding-top: 24px; font-size: 14px; }
@media (prefers-reduced-motion: no-preference) {
  .hero { animation: hero-enter 220ms var(--ease-out); }
  :root.theme-changing { transition: background-color 150ms var(--ease-out), color 150ms var(--ease-out); }
  @keyframes hero-enter { from { opacity: .86; transform: translateY(5px); } to { opacity: 1; transform: none; } }
}
@media (hover: hover) and (pointer: fine) and (prefers-reduced-motion: no-preference) {
  .button:not(:focus-visible), .task-list a:not(:focus-visible), .nav-unit a:not(:focus-visible), .theme-toggle:not(:focus-visible) { transition: background-color 120ms var(--ease-out), color 120ms var(--ease-out); }
}
.theme-instant, .theme-instant * { transition: none !important; }
@media (max-width: 1050px) {
  .page-width { width: calc(100% - 64px); }
  .hero-bottom { gap: 30px; }
  .hero-actions { flex-direction: column; }
  .unit-section { gap: 40px; grid-template-columns: 230px 1fr; }
  .guide-layout { gap: 38px; grid-template-columns: 220px minmax(0, 1fr); }
}
@media (max-width: 760px) {
  .page-width { width: calc(100% - 40px); }
  .site-header { min-height: 80px; gap: 10px; flex-wrap: wrap; padding-block: 15px; }
  .wordmark { font-size: 17px; max-width: 200px; }
  .header-nav { font-size: 12px; gap: 24px; width: 100%; }
  .theme-toggle { margin-left: auto; }
  .hero { padding-block: 42px; }
  .hero h1 { font-size: clamp(38px, 7.7vw, 57px); margin-bottom: 27px; }
  .hero-bottom { display: block; }
  .hero-copy { font-size: 16px; }
  .hero-actions { flex-direction: row; margin-top: 26px; }
  .task-directory { padding-top: 32px; }
  .directory-heading { display: block; }
  .directory-heading h2 { font-size: 27px; }
  .directory-count { display: inline-block; margin-top: 3px; }
  .unit-jumps { grid-template-columns: repeat(2, 1fr); }
  .unit-jumps a { padding-block: 14px; }
  .unit-jumps span { font-size: 12px; }
  .unit-section { display: block; padding-block: 32px; }
  .unit-intro h3 { font-size: 25px; max-width: 23ch; }
  .unit-intro p { max-width: 40ch; }
  .task-list { margin-top: 22px; }
  .task-list a { padding: 17px 0; grid-template-columns: 22px 1fr auto; gap: 10px; }
  .task-name { font-size: 15px; }
  .task-format { font-size: 11px; }
  .about-section { display: block; padding-block: 42px; }
  .about-section h2 { font-size: 28px; margin-bottom: 24px; }
  .footer-top { display: block; }
  .footer-top > a { display: block; width: fit-content; margin-bottom: 14px; }
  .guide-layout { display: block; padding-top: 18px; }
  .desktop-task-nav { display: none; }
  .breadcrumbs { margin-bottom: 18px; }
  .guide-header h1 { font-size: clamp(32px, 7vw, 42px); }
  .download { display: flex; flex-wrap: wrap; gap: 3px 18px; width: fit-content; text-align: left; justify-content: flex-start; }
  .mobile-task-nav { display: block; margin: 12px 0 32px; border-block: 1px solid var(--line); }
  .mobile-task-nav > summary { cursor: pointer; padding: 14px 0; font-size: 15px; font-weight: 550; }
  .mobile-task-nav nav { padding: 0 10px 12px; }
  .nav-unit li a { font-size: 15px; padding-block: 13px; }
  .nav-unit summary { font-size: 15px; }
  .guide-section.example { padding: 22px; }
  .guide-section h2 { font-size: 24px; }
  .guide-pager { gap: 22px; align-items: flex-start; }
  .worked-example { padding: 22px; }
  .tools-section { display: block; padding-block: 36px; }
  .tools-section h2 { font-size: 28px; }
  .tools-section ul { margin-top: 24px; }
  .tools-page { padding-top: 28px; }
  .calculator-page { padding-top: 24px; }
  .calculator-workspace { grid-template-columns: 1fr; gap: 18px; margin-top: 16px; }
  .calculator-switch { gap: 0 20px; font-size: 13px; margin-block: 12px 16px; }
  .calculator-result { padding: 20px; }
  .calculator-fields { grid-template-columns: 1fr; gap: 18px; }
}
@media print {
  :root, :root[data-theme] { --paper: #fff; --ink: #161e28; --muted: #536171; --blue: #005899; --pale: #fff; --line: #c9d2d9; color-scheme: light; }
  .hero { animation: none; }
  .site-header, .site-footer, .desktop-task-nav, .mobile-task-nav, .breadcrumbs, .guide-pager, .download, .hero-actions { display: none; }
  .page-width { width: 100%; }
  .guide-layout { display: block; padding: 0; }
  .guide-main { max-width: none; }
  .article { font-size: 11pt; max-width: none; line-height: 1.5; }
  .guide-section.example { break-inside: avoid; background: none; }
  h1, h2, h3 { break-after: avoid; }
  .page-jumps, .calculator form, .calculator-switch, .tool-return { display: none; }
  .learning-section, .calculator { font-size: 11pt; }
  .worked-example { background: none; }
  .practice-choice:not([open]) > :not(summary), .example-stages details:not([open]) > :not(summary) { display: block; }
}