:root {
  --navy:   #0C2340;
  --navy-2: #1B3E68;
  --ink:    #1A1E24;
  --body:   #4A5158;
  --muted:  #71797F;
  --faint:  #9AA0A6;
  --rule:   #EFEBE4;
  --line:   #DDD8CF;
  --fill:   #F6F4F0;
  --paper:  #FBFAF8;
  --white:  #FFFFFF;
  --serif:  "Source Serif 4", Georgia, "Times New Roman", serif;
  --sans:   system-ui, -apple-system, "Segoe UI", Roboto, Arial, sans-serif;
  --mono:   "IBM Plex Mono", ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;
}
* { box-sizing: border-box; }
body {
  margin: 0; font-family: var(--sans); background: var(--paper); color: var(--ink);
  line-height: 1.6; min-height: 100vh; -webkit-font-smoothing: antialiased;
}

/* ---- masthead ---- */
.sitenav { background: var(--white); border-bottom: 2px solid var(--navy); }
.sitenav .inner {
  max-width: 620px; margin: 0 auto; padding: 18px 28px;
  display: flex; align-items: baseline; gap: 22px; flex-wrap: wrap;
}
.sitenav .brand {
  font-family: var(--serif); font-weight: 600; font-size: 25px;
  letter-spacing: -0.015em; color: var(--navy); text-decoration: none;
}
.sitenav a.nav { font-size: 13px; color: var(--muted); text-decoration: none; padding-bottom: 2px; }
.sitenav a.nav:hover { color: var(--navy); }
.sitenav a.nav[aria-current="page"] {
  color: var(--navy); border-bottom: 1.5px solid var(--navy);
}

.wrap { max-width: 620px; margin: 0 auto; padding: 44px 28px 0; }
h1 {
  font-family: var(--serif); font-size: 40px; line-height: 1.1; font-weight: 600;
  letter-spacing: -0.02em; color: var(--navy); margin: 0 0 8px;
}
.tagline { margin: 0 0 30px; font-size: 15px; color: var(--muted); max-width: 46ch; }

/* ---- calculator card ---- */
.card { background: var(--white); border: 1px solid var(--line); border-radius: 3px; padding: 0; }

.solve {
  padding: 18px 24px; border-bottom: 1px solid var(--rule);
  display: flex; align-items: center; flex-wrap: wrap; gap: 12px; margin: 0;
}
.solve-label { font-size: 12px; color: var(--muted); margin: 0; text-transform: none; letter-spacing: 0; }
.pills {
  display: flex; flex-wrap: wrap; border: 1px solid var(--line);
  border-radius: 3px; overflow: hidden;
}
.pills button {
  font: inherit; font-size: 13px; cursor: pointer; padding: 6px 13px;
  border: 0; border-right: 1px solid var(--line);
  background: var(--white); color: var(--ink);
}
.pills button:last-child { border-right: 0; }
.pills button:hover { background: var(--fill); }
.pills button[aria-pressed="true"] { background: var(--navy); color: var(--white); }
.pills button:focus-visible { outline: 2px solid var(--navy-2); outline-offset: -2px; }

.stack { padding: 4px 24px 18px; }
.card > .stack:first-child { padding-top: 14px; }
.stack > div {
  display: flex; align-items: center; justify-content: space-between;
  gap: 16px; padding: 13px 0; border-bottom: 1px solid var(--rule); margin: 0;
}
.stack > div:last-child { border-bottom: 0; }
.hidden { display: none !important; }

label {
  font-size: 14px; font-weight: 400; color: var(--body);
  margin: 0; text-transform: none; letter-spacing: 0; flex: 0 1 auto;
}
input {
  width: 152px; padding: 6px 9px; font-family: var(--mono); font-size: 15px;
  text-align: right; border: 1px solid transparent; border-radius: 2px;
  background: var(--fill); color: var(--navy);
}
input:hover { background: #F0EDE7; }
input:focus {
  outline: none; background: var(--white);
  border-color: var(--navy-2); box-shadow: 0 0 0 2px rgba(27,62,104,.14);
}
input[type="date"] { font-size: 14px; }

.period { display: flex; gap: 6px; }
.field { position: relative; }
.field input { width: 152px; padding-right: 58px; }
.period .field input { width: 118px; padding-right: 52px; }
.unit {
  position: absolute; right: 9px; top: 50%; transform: translateY(-50%);
  font-size: 11.5px; color: var(--faint); pointer-events: none;
}

/* ---- result strip ---- */
.result {
  margin: 0; background: var(--navy); color: var(--white);
  border-radius: 0 0 2px 2px; padding: 22px 24px;
  display: flex; flex-wrap: wrap; align-items: baseline; gap: 8px 16px;
}
.result .label { order: 1; flex: 1 1 auto; font-size: 13px; color: rgba(255,255,255,.6); }
.result .value {
  order: 2; font-family: var(--mono); font-size: 36px; font-weight: 500;
  line-height: 1.05; letter-spacing: -0.01em; word-break: break-word;
}
.result .note {
  order: 3; flex-basis: 100%; font-size: 12.5px; color: rgba(255,255,255,.7);
  margin-top: 6px; padding-top: 12px; border-top: 1px solid rgba(255,255,255,.16);
}

.formula { margin-top: 18px; font-family: var(--mono); font-size: 11.5px; color: var(--muted); }

/* ---- revenue series ---- */
.series { width: calc(100% - 48px); margin: 12px 24px 0; border-collapse: collapse; }
.series td { padding: 5px 0; }
.series td.yr { width: 92px; padding-right: 10px; }
.series td.yr input, .series td input { width: 100%; }
.series td.yoy {
  width: 78px; padding-left: 12px; text-align: right;
  font-family: var(--mono); font-size: 12.5px; color: var(--muted);
}
.rowbtns { display: flex; gap: 6px; margin: 16px 24px 20px; }
.rowbtns button {
  font: inherit; font-size: 13px; cursor: pointer; padding: 6px 13px;
  border: 1px solid var(--line); border-radius: 3px;
  background: var(--white); color: var(--ink);
}
.rowbtns button:hover { background: var(--fill); border-color: var(--navy-2); }

/* ---- related ---- */
.related { max-width: 620px; margin: 44px auto 0; padding: 0 28px; }
.related h2 { font-size: 12px; font-weight: 400; color: var(--muted); margin: 0 0 10px; }
.related ul { list-style: none; margin: 0; padding: 0; display: flex; flex-wrap: wrap; gap: 6px; }
.related a {
  display: inline-block; font-size: 13px; text-decoration: none; color: var(--ink);
  background: var(--white); border: 1px solid var(--line); border-radius: 3px; padding: 6px 13px;
}
.related a:hover { border-color: var(--navy); color: var(--navy); }

/* ---- article ---- */
.article { max-width: 620px; margin: 0 auto; padding: 0 28px 80px; }
.article .divider { border: 0; border-top: 1px solid var(--line); margin: 52px 0 42px; }
.article h2 {
  font-family: var(--serif); font-size: 26px; font-weight: 600; line-height: 1.25;
  letter-spacing: -0.015em; color: var(--navy); margin: 42px 0 12px;
}
.article h2:first-of-type { margin-top: 0; }
.article h3 {
  font-family: var(--serif); font-size: 18px; font-weight: 600;
  color: var(--navy); margin: 26px 0 6px;
}
.article p { margin: 0 0 16px; font-size: 16px; max-width: 62ch; }
.article ul, .article ol { margin: 0 0 16px; padding-left: 20px; max-width: 62ch; }
.article li { margin-bottom: 6px; }
.article strong { font-weight: 600; }
.article a { color: var(--navy-2); text-underline-offset: 2px; }
.article .eq {
  display: block; background: var(--fill); border-left: 2px solid var(--navy);
  border-radius: 0; padding: 13px 16px; margin: 0 0 16px;
  font-family: var(--mono); font-size: 13.5px; line-height: 1.7; color: var(--navy);
}

footer.site { border-top: 1px solid var(--line); background: var(--white); }
footer.site .inner {
  max-width: 620px; margin: 0 auto; padding: 22px 28px; font-size: 12px; color: var(--muted);
}

@media (max-width: 620px) {
  h1 { font-size: 32px; }
  .sitenav .inner, .wrap, .related, .article, footer.site .inner { padding-left: 20px; padding-right: 20px; }
  .wrap { padding-top: 32px; }
  .stack > div { flex-wrap: wrap; gap: 6px; }
  input, .field input { width: 100%; }
  .period { width: 100%; }
  .period .field { flex: 1; }
  .period .field input { width: 100%; }
  .article h2 { font-size: 22px; }
}
@media (prefers-reduced-motion: reduce) { * { transition: none !important; } }