/* US Tax Academia — shared styles
   Palette taken from state filing paperwork: cool form paper, ink,
   ballpoint blue for filled-in entries, seal red for the filing stamp. */

:root {
  --paper: #f5f7fa;
  --sheet: #ffffff;
  --ink: #18202c;
  --ink-soft: #4a5466;
  --rule: #d4dae4;
  --rule-strong: #aab3c2;
  --pen: #2b4fb8;
  --pen-tint: #e8edfa;
  --seal: #b8322b;

  --sans: "Public Sans", system-ui, -apple-system, "Segoe UI", sans-serif;
  --serif: "Source Serif 4", Georgia, "Times New Roman", serif;
  --type: "Courier Prime", "Courier New", monospace;

  --measure: 66ch;
  --gutter: clamp(16px, 4vw, 40px);
}

*, *::before, *::after { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--serif);
  font-size: 1.125rem;
  line-height: 1.65;
  text-rendering: optimizeLegibility;
}

img { max-width: 100%; display: block; }

a { color: var(--pen); text-decoration-thickness: 1px; text-underline-offset: 3px; }
a:hover { text-decoration-thickness: 2px; }

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

.skip {
  position: absolute; left: -999px; top: 8px;
  background: var(--ink); color: #fff; padding: 8px 14px; font-family: var(--sans);
}
.skip:focus { left: 8px; z-index: 10; }

.wrap { width: 100%; max-width: 1160px; margin: 0 auto; padding: 0 var(--gutter); }

/* ---------- Header ---------- */
.site-header { border-bottom: 1px solid var(--rule); background: var(--sheet); }
.site-header .wrap {
  display: flex; align-items: center; justify-content: space-between;
  gap: 16px; min-height: 68px; flex-wrap: wrap; padding-top: 10px; padding-bottom: 10px;
}
.brand {
  font-family: var(--sans); font-weight: 800; font-size: 1.05rem;
  color: var(--ink); text-decoration: none; letter-spacing: -0.01em;
  display: inline-flex; align-items: center; gap: 10px;
}
.brand-mark {
  width: 36px; height: 36px; border: 2px solid var(--ink); border-radius: 50%;
  display: grid; place-items: center; font-size: 0.56rem; font-weight: 800; letter-spacing: 0.02em;
}
.nav { display: flex; gap: 4px; flex-wrap: wrap; font-family: var(--sans); font-size: 0.95rem; }
.nav a {
  color: var(--ink-soft); text-decoration: none; padding: 6px 12px; border-radius: 4px;
}
.nav a:hover { color: var(--ink); background: var(--paper); }
.nav a[aria-current="page"] { color: var(--ink); font-weight: 700; box-shadow: inset 0 -2px 0 var(--pen); border-radius: 0; }

/* ---------- Type ---------- */
h1, h2, h3, h4 { font-family: var(--sans); color: var(--ink); line-height: 1.15; letter-spacing: -0.02em; margin: 0; }
h1 { font-size: clamp(2.2rem, 5.2vw, 3.6rem); font-weight: 800; letter-spacing: -0.03em; }
h2 { font-size: clamp(1.6rem, 3vw, 2.1rem); font-weight: 750; }
h3 { font-size: 1.25rem; font-weight: 700; letter-spacing: -0.01em; }
p { margin: 0 0 1.1em; }
.lede { font-size: 1.28rem; line-height: 1.55; color: var(--ink-soft); max-width: 40ch; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-block; font-family: var(--sans); font-weight: 700; font-size: 1rem;
  padding: 13px 22px; border-radius: 4px; text-decoration: none; border: 2px solid var(--ink);
}
.btn-primary { background: var(--ink); color: #fff; }
.btn-primary:hover { background: var(--pen); border-color: var(--pen); }
.btn-ghost { color: var(--ink); background: transparent; }
.btn-ghost:hover { background: var(--sheet); }
.actions { display: flex; gap: 12px; flex-wrap: wrap; margin-top: 28px; }

/* ---------- Hero (home) ---------- */
.hero { padding: clamp(48px, 8vw, 96px) 0 clamp(56px, 8vw, 104px); }
.hero .wrap { display: grid; grid-template-columns: 1.05fr 1fr; gap: clamp(32px, 6vw, 80px); align-items: center; }
.hero h1 { max-width: 13ch; margin-bottom: 24px; }

.form-doc {
  position: relative; background: var(--sheet); border: 1px solid var(--rule-strong);
  padding: 28px 28px 22px; transform: rotate(1.2deg);
  box-shadow: 0 1px 0 var(--rule), 8px 10px 0 -2px var(--rule);
  font-family: var(--sans); color: var(--ink);
}
.form-doc header { display: flex; justify-content: space-between; align-items: flex-start; gap: 12px; border-bottom: 2px solid var(--ink); padding-bottom: 12px; margin-bottom: 6px; }
.form-doc .form-title { font-weight: 800; font-size: 1.15rem; line-height: 1.2; }
.form-doc .form-sub { font-size: 0.78rem; color: var(--ink-soft); margin-top: 4px; }
.form-doc .form-no { font-size: 0.72rem; color: var(--ink-soft); text-align: right; white-space: nowrap; }
.field { display: grid; grid-template-columns: 1.6rem 1fr; gap: 0 8px; padding: 12px 0 8px; border-bottom: 1px solid var(--rule); }
.field .n { font-size: 0.75rem; font-weight: 700; color: var(--ink-soft); padding-top: 2px; }
.field label { font-size: 0.75rem; color: var(--ink-soft); display: block; }
.field .entry {
  font-family: var(--type); color: var(--pen); font-size: 1.02rem; min-height: 1.5em; line-height: 1.5;
  grid-column: 2;
}
.field .entry.typing::after { content: ""; display: inline-block; width: 2px; height: 1em; background: var(--pen); vertical-align: -2px; margin-left: 1px; animation: blink 0.8s steps(1) infinite; }
@keyframes blink { 50% { opacity: 0; } }
.form-doc .sign { display: flex; justify-content: space-between; gap: 16px; font-size: 0.72rem; color: var(--ink-soft); padding-top: 18px; }
.form-doc .sign span { flex: 1; border-top: 1px solid var(--ink); padding-top: 4px; }

.stamp {
  position: absolute; right: 18px; bottom: 54px;
  border: 3px solid var(--seal); color: var(--seal); border-radius: 6px;
  padding: 6px 14px 4px; font-family: var(--sans); font-weight: 800; text-align: center;
  transform: rotate(-11deg); opacity: 0; mix-blend-mode: multiply; pointer-events: none;
}
.stamp b { display: block; font-size: 1.7rem; letter-spacing: 0.12em; line-height: 1; }
.stamp small { display: block; font-size: 0.62rem; font-weight: 700; letter-spacing: 0.04em; margin-top: 3px; }
.stamp.down { animation: stamp 0.42s cubic-bezier(.2,1.6,.4,1) forwards; }
@keyframes stamp {
  0% { opacity: 0; transform: rotate(-11deg) scale(1.8); }
  100% { opacity: 0.9; transform: rotate(-11deg) scale(1); }
}
@media (prefers-reduced-motion: reduce) {
  .stamp { opacity: 0.9; }
  .stamp.down { animation: none; }
  .field .entry.typing::after { display: none; }
}

/* ---------- Home sections ---------- */
.band { padding: clamp(56px, 8vw, 96px) 0; border-top: 1px solid var(--rule); }
.band.white { background: var(--sheet); }
.band h2 { max-width: 22ch; margin-bottom: 18px; }
.band .intro { max-width: var(--measure); color: var(--ink-soft); }

.two-col { display: grid; grid-template-columns: 1fr 1fr; gap: clamp(28px, 5vw, 64px); align-items: start; }

.guides { list-style: none; margin: 36px 0 0; padding: 0; border-top: 2px solid var(--ink); }
.guides li { border-bottom: 1px solid var(--rule); }
.guides a {
  display: grid; grid-template-columns: 1fr auto; gap: 6px 24px; padding: 26px 0;
  text-decoration: none; color: var(--ink);
}
.guides a:hover h3 { color: var(--pen); }
.guides h3 { font-size: clamp(1.3rem, 2.4vw, 1.6rem); }
.guides p { margin: 0; color: var(--ink-soft); grid-column: 1; max-width: 60ch; }
.guides .meta { font-family: var(--sans); font-size: 0.9rem; color: var(--ink-soft); grid-row: 1; grid-column: 2; align-self: center; white-space: nowrap; }

.steps-short { counter-reset: s; list-style: none; padding: 0; margin: 32px 0 0; display: grid; grid-template-columns: repeat(3, 1fr); gap: 0; border-left: 1px solid var(--rule); }
.steps-short li { counter-increment: s; padding: 4px 22px 28px; border-right: 1px solid var(--rule); border-bottom: 1px solid var(--rule); }
.steps-short li::before {
  content: counter(s); display: block; font-family: var(--sans); font-weight: 800; font-size: 2.4rem;
  color: var(--pen); line-height: 1; margin: 18px 0 12px;
}
.steps-short h3 { margin-bottom: 8px; }
.steps-short p { font-size: 1rem; color: var(--ink-soft); margin: 0; }

.duty-list { list-style: none; padding: 0; margin: 0; }
.duty-list li { padding: 14px 0 14px 34px; border-bottom: 1px solid var(--rule); position: relative; }
.duty-list li::before {
  content: ""; position: absolute; left: 0; top: 20px; width: 16px; height: 16px;
  border: 2px solid var(--ink); border-radius: 2px;
  background: linear-gradient(45deg, transparent 44%, var(--pen) 44%, var(--pen) 56%, transparent 56%),
              linear-gradient(-45deg, transparent 44%, var(--pen) 44%, var(--pen) 56%, transparent 56%);
}
.duty-list strong { font-family: var(--sans); }

/* ---------- Article layout ---------- */
.article-head { padding: clamp(44px, 7vw, 84px) 0 36px; border-bottom: 1px solid var(--rule); background: var(--sheet); }
.article-head h1 { max-width: 18ch; margin: 14px 0 20px; }
.article-head .lede { max-width: 54ch; }
.crumb { font-family: var(--sans); font-size: 0.9rem; color: var(--ink-soft); }
.crumb a { color: var(--ink-soft); }
.byline { font-family: var(--sans); font-size: 0.9rem; color: var(--ink-soft); margin-top: 24px; }

.article-body { display: grid; grid-template-columns: 220px minmax(0, var(--measure)); gap: clamp(32px, 6vw, 80px); padding-top: 48px; padding-bottom: 80px; }
.toc { position: sticky; top: 24px; align-self: start; font-family: var(--sans); font-size: 0.92rem; }
.toc h2 { font-size: 0.95rem; font-weight: 700; margin-bottom: 10px; letter-spacing: 0; }
.toc ol, .toc ul { margin: 0; padding: 0; list-style: none; border-left: 2px solid var(--rule); }
.toc a { display: block; padding: 5px 0 5px 14px; color: var(--ink-soft); text-decoration: none; margin-left: -2px; border-left: 2px solid transparent; line-height: 1.35; }
.toc a:hover { color: var(--ink); border-left-color: var(--pen); }

.prose h2 { margin: 2.2em 0 0.6em; scroll-margin-top: 24px; }
.prose h2:first-child { margin-top: 0; }
.prose h3 { margin: 1.8em 0 0.5em; }
.prose ul, .prose ol { padding-left: 1.3em; margin: 0 0 1.2em; }
.prose li { margin-bottom: 0.45em; }
.prose li::marker { color: var(--ink-soft); }
.prose strong { font-weight: 650; }

.note {
  border-left: 4px solid var(--pen); background: var(--pen-tint); padding: 16px 20px; margin: 1.6em 0;
  font-size: 1.02rem;
}
.note p:last-child { margin-bottom: 0; }
.note .note-h { font-family: var(--sans); font-weight: 700; display: block; margin-bottom: 4px; }
.note.warn { border-left-color: var(--seal); background: #fbeeed; }

/* numbered steps — the guide really is a sequence */
.step { display: grid; grid-template-columns: 56px 1fr; gap: 0 18px; margin: 2.6em 0 0; scroll-margin-top: 24px; }
.step-num {
  font-family: var(--sans); font-weight: 800; font-size: 1.15rem; width: 44px; height: 44px;
  border: 2px solid var(--ink); border-radius: 50%; display: grid; place-items: center; background: var(--sheet);
}
.step h2 { margin: 6px 0 0.6em; }
.step > div > :last-child { margin-bottom: 0; }

.table-scroll { overflow-x: auto; margin: 1.4em 0 1.6em; border: 1px solid var(--rule); background: var(--sheet); }
table { border-collapse: collapse; width: 100%; font-family: var(--sans); font-size: 0.95rem; }
th, td { text-align: left; padding: 12px 14px; border-bottom: 1px solid var(--rule); vertical-align: top; }
th { font-weight: 700; background: var(--paper); }
tr:last-child td { border-bottom: 0; }

.checklist { list-style: none; padding: 0 !important; }
.checklist li { position: relative; padding-left: 30px; }
.checklist li::before { content: ""; position: absolute; left: 0; top: 0.35em; width: 15px; height: 15px; border: 2px solid var(--ink-soft); border-radius: 2px; }

/* ---------- FAQ ---------- */
.faq { max-width: 760px; padding-top: 40px; padding-bottom: 80px; }
.faq details { border-bottom: 1px solid var(--rule); }
.faq details:first-of-type { border-top: 2px solid var(--ink); }
.faq summary {
  cursor: pointer; list-style: none; padding: 22px 40px 22px 0; position: relative;
  font-family: var(--sans); font-weight: 700; font-size: 1.12rem; line-height: 1.35;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after {
  content: "+"; position: absolute; right: 4px; top: 18px; font-size: 1.5rem; font-weight: 400; color: var(--pen);
  transition: transform 0.2s ease;
}
.faq details[open] summary::after { transform: rotate(45deg); }
.faq .answer { padding: 0 0 18px; max-width: 64ch; }
@media (prefers-reduced-motion: reduce) { .faq summary::after { transition: none; } }

/* ---------- CTA + Footer ---------- */
.next-up { border: 2px solid var(--ink); background: var(--sheet); padding: 24px 26px; margin-top: 3em; }
.next-up h2 { font-size: 1.3rem; margin: 0 0 8px; }
.next-up p { margin: 0 0 16px; color: var(--ink-soft); }

.site-footer { background: var(--ink); color: #c9d0dc; padding: 48px 0 40px; font-family: var(--sans); font-size: 0.92rem; }
.site-footer .wrap { display: grid; grid-template-columns: 1.4fr 1fr; gap: 32px; }
.site-footer a { color: #fff; }
.site-footer .brand { color: #fff; margin-bottom: 12px; }
.site-footer .brand-mark { border-color: #fff; }
.site-footer nav ul { list-style: none; margin: 0; padding: 0; display: grid; gap: 8px; }
.disclaimer { grid-column: 1 / -1; border-top: 1px solid #36404f; padding-top: 22px; font-size: 0.84rem; line-height: 1.6; color: #a3acbb; max-width: 90ch; }

/* ---------- Responsive ---------- */
@media (max-width: 920px) {
  .hero .wrap { grid-template-columns: 1fr; }
  .form-doc { max-width: 520px; transform: rotate(0.8deg); }
  .two-col { grid-template-columns: 1fr; }
  .steps-short { grid-template-columns: repeat(2, 1fr); }
  .article-body { grid-template-columns: 1fr; padding-top: 32px; }
  .toc { position: static; border: 1px solid var(--rule); background: var(--sheet); padding: 16px 18px; }
}
@media (max-width: 600px) {
  body { font-size: 1.06rem; }
  .steps-short { grid-template-columns: 1fr; }
  .guides a { grid-template-columns: 1fr; }
  .guides .meta { grid-row: auto; grid-column: 1; }
  .form-doc { padding: 20px 18px 18px; transform: none; box-shadow: 5px 6px 0 -1px var(--rule); }
  .step { grid-template-columns: 1fr; }
  .step-num { margin-bottom: 4px; }
  .site-footer .wrap { grid-template-columns: 1fr; }
  .nav a { padding: 6px 8px; }
}