/* ==========================================================================
   TaxWorkbooks — landing page
   Self-contained stylesheet. No imports, no web fonts, no remote assets.
   Design register: a well-prepared file memo. Hairline rules instead of
   shadows, a working-paper reference number beside every section head,
   tabular figures, one accent colour used sparingly.
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. Tokens
   -------------------------------------------------------------------------- */
:root {
  /* Ink and paper */
  --ink:          #101a2b;
  --navy:         #17273f;
  --navy-700:     #22354f;
  --slate:        #4c5a6e;
  --muted:        #5f6c7e;
  --rule:         #dfe3e9;
  --rule-faint:   #eceff3;
  --rule-strong:  #c3cad4;
  --paper:        #ffffff;
  --paper-alt:    #f4f6f8;
  --accent:       #1f4e79;
  --accent-soft:  #e9eef4;

  /* Type */
  --serif: Georgia, "Iowan Old Style", "Times New Roman", Times, serif;
  --sans:  -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue", Arial, sans-serif;
  --mono:  ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;

  /* Rhythm */
  --gutter: 1.25rem;
  /* One document column governs every section, so section rules and card edges
     share a single left and right edge at every width. */
  --wrap-max: 1180px;
  --measure: 68ch;
  --sec-pad: clamp(3.25rem, 5.5vw, 5.75rem);
  --radius: 2px;
}

/* --------------------------------------------------------------------------
   2. Reset and base
   -------------------------------------------------------------------------- */
*, *::before, *::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--slate);
  font-family: var(--sans);
  font-size: 1.0625rem;
  line-height: 1.62;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

h1, h2, h3, h4 {
  color: var(--ink);
  font-family: var(--serif);
  font-weight: 400;
  line-height: 1.18;
  margin: 0;
  letter-spacing: -0.01em;
}

p { margin: 0 0 1em; }
p:last-child { margin-bottom: 0; }

ul, ol { margin: 0; padding: 0; }

a {
  color: var(--accent);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 0.18em;
  text-decoration-color: var(--rule-strong);
  transition: text-decoration-color 140ms ease, color 140ms ease;
}
a:hover { text-decoration-color: currentColor; }

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 1px;
}

strong { color: var(--ink); font-weight: 600; }

:target { scroll-margin-top: 1.75rem; }

.mono {
  font-family: var(--mono);
  font-size: 0.9em;
  color: var(--ink);
}

.wrap { width: min(100% - (var(--gutter) * 2), var(--wrap-max)); margin-inline: auto; }

.skip {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--navy);
  color: #fff;
  padding: 0.75rem 1rem;
  z-index: 10;
  text-decoration: none;
}
.skip:focus { left: 0; }

/* --------------------------------------------------------------------------
   3. Masthead — brand, nav, hero, memo block
   -------------------------------------------------------------------------- */
.masthead {
  background: var(--paper);
  border-bottom: 1px solid var(--rule);
  padding-bottom: clamp(2.5rem, 4.5vw, 4.25rem);
}

.topbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem 1.5rem;
  padding: 1.15rem 0;
  border-bottom: 1px solid var(--rule-faint);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  text-decoration: none;
  color: var(--ink);
}
.brand-mark {
  width: 0.9rem;
  height: 0.9rem;
  background: var(--navy);
  border-radius: 1px;
  position: relative;
  flex: 0 0 auto;
}
.brand-mark::after {
  content: "";
  position: absolute;
  inset: 0.22rem 0.22rem auto 0.22rem;
  height: 1px;
  background: var(--paper);
  box-shadow: 0 0.22rem 0 var(--paper);
}
.brand-name {
  font-family: var(--serif);
  font-size: 1.2rem;
  letter-spacing: -0.015em;
  color: var(--ink);
}

.topnav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem 1.5rem;
  list-style: none;
  font-size: 0.9375rem;
}
.topnav a {
  color: var(--slate);
  text-decoration: none;
  padding-bottom: 2px;
  border-bottom: 1px solid transparent;
}
.topnav a:hover { color: var(--ink); border-bottom-color: var(--rule-strong); }

.hero {
  display: grid;
  gap: clamp(2rem, 4vw, 3.5rem);
  padding-top: clamp(2.5rem, 5vw, 4.5rem);
}

.hero-copy h1 {
  font-size: clamp(2.05rem, 1.35rem + 2.9vw, 3.3rem);
  line-height: 1.08;
  letter-spacing: -0.02em;
}
.lede {
  margin-top: 1.15rem;
  max-width: 46ch;
  font-size: clamp(1.0625rem, 1rem + 0.35vw, 1.1875rem);
  color: var(--slate);
}

/* The memo block: a file header, not a feature list */
.memo {
  margin: 0;
  border-top: 2px solid var(--navy);
  align-self: start;
}
.memo-row {
  display: grid;
  grid-template-columns: 6.25rem 1fr;
  gap: 0 1rem;
  padding: 0.6rem 0;
  border-bottom: 1px solid var(--rule);
}
.memo dt {
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.09em;
  text-transform: uppercase;
  color: var(--muted);
  padding-top: 0.22em;
}
.memo dd {
  margin: 0;
  color: var(--ink);
  font-size: 0.9375rem;
}

/* --------------------------------------------------------------------------
   4. Credibility strip
   -------------------------------------------------------------------------- */
.credibility {
  background: var(--navy);
  color: #d7dee8;
  padding: clamp(2rem, 3.5vw, 2.75rem) 0;
}
.credential {
  font-family: var(--serif);
  font-size: clamp(1.125rem, 1rem + 0.7vw, 1.4rem);
  line-height: 1.35;
  color: #fff;
  max-width: 34ch;
  margin-bottom: 1.75rem;
}
.badges {
  display: grid;
  gap: 1.25rem 2.5rem;
  list-style: none;
  border-top: 1px solid rgba(255, 255, 255, 0.16);
  padding-top: 1.5rem;
}
.badges li { display: block; }
.badge-label {
  display: block;
  font-family: var(--mono);
  font-size: 0.75rem;
  letter-spacing: 0.11em;
  text-transform: uppercase;
  color: #fff;
  margin-bottom: 0.4rem;
}
.badge-note {
  display: block;
  font-size: 0.9375rem;
  line-height: 1.5;
  color: #aebac9;
  max-width: 34ch;
}

/* --------------------------------------------------------------------------
   5. Sections and section heads
   -------------------------------------------------------------------------- */
.section { padding: var(--sec-pad) 0; }
.section-alt {
  background: var(--paper-alt);
  border-top: 1px solid var(--rule);
  border-bottom: 1px solid var(--rule);
}
.section-legal {
  border-top: 1px solid var(--rule);
  padding-bottom: clamp(2.5rem, 4vw, 4rem);
}

.sec-head {
  display: grid;
  gap: 0.5rem 1.5rem;
  border-top: 2px solid var(--navy);
  padding-top: 0.9rem;
  margin-bottom: clamp(2rem, 3.5vw, 3rem);
}
.sec-num {
  font-family: var(--mono);
  font-size: 0.75rem;
  letter-spacing: 0.1em;
  color: var(--muted);
  margin: 0;
  padding-top: 0.35em;
}
.sec-head h2 { font-size: clamp(1.55rem, 1.2rem + 1.5vw, 2.15rem); }
.sec-sub {
  margin: 0.7rem 0 0;
  max-width: 62ch;
  color: var(--slate);
}

/* --------------------------------------------------------------------------
   6. Product cards
   -------------------------------------------------------------------------- */
.cards { display: grid; gap: 1.5rem; }

.card {
  display: flex;
  flex-direction: column;
  background: var(--paper);
  border: 1px solid var(--rule);
  border-top: 3px solid var(--navy);
  border-radius: var(--radius);
  padding: 1.6rem 1.5rem 1.5rem;
  width: 100%;
  transition: border-color 160ms ease;
}
.card:hover { border-color: var(--rule-strong); border-top-color: var(--navy); }
.card-flagship { border-top-color: var(--accent); }
.card-flagship:hover { border-top-color: var(--accent); }

.card-kicker {
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.11em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 0.55rem;
}
.card-head { margin-bottom: 1.5rem; }
.card-head h3 {
  font-size: 1.375rem;
  line-height: 1.2;
  margin-bottom: 0.75rem;
}
.card-summary {
  font-size: 0.9375rem;
  line-height: 1.6;
  color: var(--slate);
}

/* Screenshot slot (Task 10). Styles ship ready so the markup can simply be uncommented. */
.shot { margin: 0 0 1.4rem; }
.shot img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--rule);
  border-radius: var(--radius);
  background: var(--paper-alt);
}
.shot figcaption {
  margin-top: 0.55rem;
  font-size: 0.8125rem;
  line-height: 1.45;
  color: var(--muted);
}

/* The body grows to fill the card so the disclosure row and the price rule below it
   land in the same band on all three cards, whatever the list length. */
.card-body {
  flex: 1 1 auto;
  display: flex;
  flex-direction: column;
  margin-bottom: 1.5rem;
}

.inside-label {
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.11em;
  text-transform: uppercase;
  color: var(--ink);
  margin-bottom: 0.5rem;
}
.inside {
  list-style: none;
  font-size: 0.9375rem;
  line-height: 1.5;
}
.inside li {
  position: relative;
  padding: 0.55rem 0 0.55rem 1.1rem;
  border-top: 1px solid var(--rule-faint);
  color: var(--slate);
}
.inside li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 1.13em;
  width: 5px;
  height: 5px;
  background: var(--accent);
  border-radius: 1px;
}

/* "See full details" disclosure */
.more { margin-top: auto; border-top: 1px solid var(--rule); }
.more > summary {
  list-style: none;
  cursor: pointer;
  padding: 0.85rem 1.5rem 0 0;
  position: relative;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--accent);
}
.more > summary::-webkit-details-marker { display: none; }
.more > summary::after {
  content: "+";
  position: absolute;
  right: 0;
  top: 0.75rem;
  font-family: var(--mono);
  font-size: 1rem;
  color: var(--muted);
}
.more[open] > summary::after { content: "\2013"; }
.more > summary:hover { color: var(--ink); }

.more-body { padding-top: 0.9rem; }
.more-body h4 {
  font-family: var(--sans);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
  margin: 1.15rem 0 0.35rem;
}
.more-body h4:first-child { margin-top: 0; }
.more-body p {
  font-size: 0.9375rem;
  line-height: 1.6;
  margin-bottom: 0;
  color: var(--slate);
}

/* Card footer: price, licence line, buy */
.card-foot {
  margin-top: auto;
  border-top: 1px solid var(--rule);
  padding-top: 1.25rem;
}
.price {
  display: flex;
  align-items: baseline;
  gap: 0.5rem;
  margin-bottom: 0.4rem;
  font-family: var(--mono);
  font-variant-numeric: tabular-nums;
}
.price .cur {
  font-size: 0.6875rem;
  letter-spacing: 0.11em;
  color: var(--muted);
}
.price .amt {
  font-size: 1.75rem;
  color: var(--ink);
  letter-spacing: -0.01em;
}
.licence-line {
  font-size: 0.8125rem;
  line-height: 1.45;
  color: var(--muted);
  margin-bottom: 1.1rem;
}

.buy {
  display: block;
  width: 100%;
  background: var(--navy);
  color: #fff;
  border: 1px solid var(--navy);
  border-radius: var(--radius);
  padding: 0.85rem 1.25rem;
  font-family: var(--sans);
  font-size: 0.9375rem;
  font-weight: 600;
  letter-spacing: 0.01em;
  text-align: center;
  text-decoration: none;
  cursor: pointer;
  transition: background-color 140ms ease, border-color 140ms ease;
}
.buy:hover { background: var(--accent); border-color: var(--accent); }
.buy-secondary { width: auto; }

.buy-note {
  margin-top: 0.6rem;
  font-size: 0.8125rem;
  color: var(--muted);
  text-align: center;
}

/* --------------------------------------------------------------------------
   7. Sample strip
   -------------------------------------------------------------------------- */
.samples {
  display: grid;
  gap: 1rem;
  list-style: none;
}
.samples li {
  background: var(--paper);
  border: 1px dashed var(--rule-strong);
  border-radius: var(--radius);
  padding: 1.15rem 1.25rem;
}
.sample-name {
  display: block;
  font-family: var(--serif);
  font-size: 1.0625rem;
  color: var(--ink);
  margin-bottom: 0.45rem;
}
.sample-state {
  display: block;
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.09em;
  text-transform: uppercase;
  color: var(--muted);
}
.samples-note {
  margin-top: 1.15rem;
  font-size: 0.875rem;
  color: var(--muted);
}

/* --------------------------------------------------------------------------
   8. How these are built
   -------------------------------------------------------------------------- */
.standard {
  list-style: none;
  counter-reset: std;
  display: grid;
  gap: 1.75rem 3rem;
}
.standard li {
  counter-increment: std;
  position: relative;
  padding-left: 2.6rem;
}
.standard li::before {
  content: counter(std, decimal-leading-zero);
  position: absolute;
  left: 0;
  top: 0.15em;
  font-family: var(--mono);
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  color: var(--accent);
}
.standard h3 {
  font-family: var(--sans);
  font-size: 1rem;
  font-weight: 600;
  letter-spacing: 0;
  margin-bottom: 0.3rem;
}
.standard p {
  font-size: 0.9375rem;
  line-height: 1.58;
  margin: 0;
  max-width: 46ch;
}

/* --------------------------------------------------------------------------
   9. FAQ
   -------------------------------------------------------------------------- */
.faq { border-top: 1px solid var(--rule-strong); }
.faq details { border-bottom: 1px solid var(--rule); }
.faq summary {
  list-style: none;
  cursor: pointer;
  position: relative;
  padding: 1.05rem 2.25rem 1.05rem 0;
  font-size: 1rem;
  font-weight: 600;
  color: var(--ink);
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after {
  content: "+";
  position: absolute;
  right: 0.25rem;
  top: 0.95rem;
  font-family: var(--mono);
  font-size: 1.0625rem;
  color: var(--muted);
}
.faq details[open] summary::after { content: "\2013"; }
.faq summary:hover { color: var(--accent); }
.faq-body {
  padding: 0 2.25rem 1.25rem 0;
  max-width: var(--measure);
}
.faq-body p {
  font-size: 0.9375rem;
  line-height: 1.62;
  margin: 0;
}

/* --------------------------------------------------------------------------
   9b. Split layout — reading column plus a marginalia column
   The right column carries the short annotations a working paper keeps in its
   margin. Below the wide breakpoint it stacks under the content it annotates.
   -------------------------------------------------------------------------- */
.split { display: grid; gap: 2.25rem; }

/* Stacked below its content when narrow (rule spans the column, like every other
   rule on the page); constrained by the 17rem grid column when wide. */
.margin-note {
  border-top: 1px solid var(--rule-strong);
  padding-top: 0.9rem;
  font-size: 0.875rem;
  line-height: 1.55;
  color: var(--muted);
}
.margin-note p { margin: 0; }
.margin-note p + p { margin-top: 0.7rem; }
.margin-label {
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.11em;
  text-transform: uppercase;
  color: var(--ink);
}
.margin-note .margin-label { margin-bottom: 0.55rem; }

/* --------------------------------------------------------------------------
   10. Email signup
   -------------------------------------------------------------------------- */
.signup {
  display: grid;
  gap: 0.85rem;
  align-items: end;
  max-width: 34rem;
  padding: 1.5rem;
  background: var(--paper-alt);
  border: 1px solid var(--rule);
  border-radius: var(--radius);
}
.signup-field { display: block; }
.signup label {
  display: block;
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.09em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 0.4rem;
}
.signup input {
  display: block;
  width: 100%;
  font-family: var(--sans);
  font-size: 1rem;
  color: var(--ink);
  background: var(--paper);
  border: 1px solid var(--rule-strong);
  border-radius: var(--radius);
  padding: 0.7rem 0.75rem;
}
.signup input::placeholder { color: var(--muted); }
.signup input:focus-visible { border-color: var(--accent); outline-offset: 1px; }

/* --------------------------------------------------------------------------
   11. Legal
   -------------------------------------------------------------------------- */
.legal-doc {
  max-width: 74ch;
  font-size: 0.9375rem;
  line-height: 1.6;
  padding-top: 1.5rem;
  border-top: 1px solid var(--rule);
  margin-top: 2rem;
}
.legal-doc:first-of-type { margin-top: 0; border-top: 0; padding-top: 0; }
.legal-doc h3 { font-size: 1.3rem; margin-bottom: 0.35rem; }
.legal-doc h4 {
  font-family: var(--sans);
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--ink);
  margin: 1.6rem 0 0.4rem;
}
.legal-doc ul {
  list-style: none;
  margin: 0 0 1em;
}
.legal-doc li {
  position: relative;
  padding-left: 1.1rem;
  margin-bottom: 0.4rem;
}
.legal-doc li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.72em;
  width: 4px;
  height: 1px;
  background: var(--rule-strong);
}
.legal-meta {
  font-family: var(--mono);
  font-size: 0.75rem;
  letter-spacing: 0.05em;
  color: var(--muted);
  margin-bottom: 1.4rem;
}
.legal-contact { margin-top: 1.6rem; }

/* --------------------------------------------------------------------------
   12. Footer
   -------------------------------------------------------------------------- */
.sitefoot {
  background: var(--navy);
  color: #aebac9;
  padding: clamp(2.75rem, 4.5vw, 3.75rem) 0 2.5rem;
  font-size: 0.9375rem;
}
.foot-grid {
  display: grid;
  gap: 2rem 3rem;
  padding-bottom: 2rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.16);
}
.sitefoot .brand-name { color: #fff; display: block; margin-bottom: 0.5rem; }
.foot-tag { color: #aebac9; max-width: 30ch; margin-bottom: 0.6rem; }
.foot-domain {
  font-family: var(--mono);
  font-size: 0.8125rem;
  letter-spacing: 0.04em;
  color: #8a99ad;
}
.foot-head {
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.11em;
  text-transform: uppercase;
  color: #8a99ad;
  margin-bottom: 0.75rem;
}
.foot-links ul { list-style: none; }
.foot-links li { margin-bottom: 0.45rem; }
.foot-links a {
  color: #d7dee8;
  text-decoration: none;
  border-bottom: 1px solid transparent;
  padding-bottom: 1px;
}
.foot-links a:hover { color: #fff; border-bottom-color: rgba(255, 255, 255, 0.4); }

.disclaimer {
  margin: 2rem 0 0;
  max-width: 76ch;
  font-size: 0.875rem;
  line-height: 1.6;
  color: #aebac9;
}
.disclaimer strong { color: #fff; }
.copyright {
  margin-top: 1.5rem;
  font-family: var(--mono);
  font-size: 0.75rem;
  letter-spacing: 0.05em;
  color: #8a99ad;
}

/* --------------------------------------------------------------------------
   13. Breakpoints
   -------------------------------------------------------------------------- */

/* 560px and up — signup becomes a single row */
@media (min-width: 35rem) {
  .signup {
    grid-template-columns: 1fr auto;
    gap: 0.75rem;
  }
  /* Match the button's box to the input's so the pair sits on one line cleanly. */
  .signup .buy {
    font-size: 1rem;
    padding: 0.72rem 1.5rem;
  }
}

/* 700px and up — a single 640px document column, shared by every section so the
   section rules stay flush with the card edges. */
@media (min-width: 43.75rem) {
  :root { --gutter: 2rem; --wrap-max: 40rem; }
  .badges { grid-template-columns: repeat(3, 1fr); }
  .samples { grid-template-columns: repeat(3, 1fr); }
  .sec-head { grid-template-columns: 4rem 1fr; }
  .foot-grid { grid-template-columns: 1.6fr 1fr 1fr; }
}

/* 1060px and up — the page opens out to its full grid.
   Below this width the document column stays single-file, so the hero, the
   cards and the standard list all break to one column together rather than
   being squeezed into halves of a narrow column. */
@media (min-width: 66.25rem) {
  :root { --wrap-max: 1180px; }

  .hero {
    grid-template-columns: 1.5fr 1fr;
    align-items: start;
    column-gap: clamp(2.5rem, 5vw, 5rem);
  }
  .credential { max-width: 40ch; }
  .sec-head { grid-template-columns: 5.5rem 1fr; }

  .cards { grid-template-columns: repeat(3, 1fr); gap: 1.75rem; }

  /* Column flow so the visible counter reads down each column: 01-06, then 07-11. */
  .standard {
    grid-template-columns: 1fr 1fr;
    grid-template-rows: repeat(6, auto);
    grid-auto-flow: column;
  }

  .split { grid-template-columns: minmax(0, 1fr) 17rem; gap: 3rem; align-items: start; }
  .signup { max-width: 44rem; }
}

/* --------------------------------------------------------------------------
   14. Motion — one restrained load reveal, above the fold only
   -------------------------------------------------------------------------- */
@keyframes rise {
  from { opacity: 0; transform: translateY(8px); }
  to   { opacity: 1; transform: none; }
}
@media (prefers-reduced-motion: no-preference) {
  .hero-copy,
  .memo,
  .credibility .wrap {
    animation: rise 420ms cubic-bezier(0.22, 0.61, 0.36, 1) both;
  }
  .memo { animation-delay: 70ms; }
  .credibility .wrap { animation-delay: 130ms; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}

/* --------------------------------------------------------------------------
   15. Print — the page should print like the documents it sells
   -------------------------------------------------------------------------- */
@media print {
  body { font-size: 10.5pt; color: #000; background: #fff; }
  .topnav, .buy, .signup, .skip, .shot { display: none; }
  .credibility, .sitefoot { background: #fff; color: #000; }
  .credential, .badge-label, .sitefoot .brand-name, .disclaimer strong { color: #000; }
  .badge-note, .foot-tag, .disclaimer, .copyright, .foot-domain { color: #333; }
  .section, .masthead { padding: 0.75rem 0; }
  .card, .samples li, .signup { break-inside: avoid; border-color: #999; }
  a { color: #000; text-decoration: underline; }
}