:root {
  --paper: #f6f4ee;
  --card: #fffdf8;
  --ink: #1a1e1c;
  --muted: #5d6460;
  --rule: #dcd7cb;
  --accent: #1d6b47;
  --accent-ink: #ffffff;
  --accent-soft: #e3efe7;
  --neg: #a8322a;
  --neg-soft: #f7e4e1;
  --serif: "IBM Plex Serif", Georgia, serif;
  --sans: "IBM Plex Sans", system-ui, -apple-system, Segoe UI, sans-serif;
  --mono: "IBM Plex Mono", ui-monospace, Menlo, monospace;
  --radius: 10px;
  --wrap: 1080px;
}
@media (prefers-color-scheme: dark) {
  :root {
    --paper: #141816;
    --card: #1b201d;
    --ink: #e9ebe7;
    --muted: #a3aba6;
    --rule: #2f3632;
    --accent: #5cc08c;
    --accent-ink: #0d1a13;
    --accent-soft: #1f3328;
    --neg: #f08a80;
    --neg-soft: #3a2220;
  }
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 16px/1.6 var(--sans);
}
a { color: var(--accent); text-underline-offset: 2px; }
img { max-width: 100%; }
.wrap { max-width: var(--wrap); margin: 0 auto; padding: 0 16px; }

/* Header and footer */
.site-head { border-bottom: 1px solid var(--rule); background: var(--card); }
.site-head .wrap { display: flex; align-items: center; justify-content: space-between; gap: 6px 16px; min-height: 60px; flex-wrap: wrap; padding-block: 12px; }
.brand { font: 600 1.2rem/1 var(--serif); color: var(--ink); text-decoration: none; letter-spacing: -0.01em; }
.brand span { color: var(--accent); }
.nav { display: flex; gap: 18px; flex-wrap: wrap; font-size: 0.95rem; }
.nav a { color: var(--muted); text-decoration: none; }
.nav a:hover { color: var(--ink); }
.site-foot { margin-top: 64px; border-top: 1px solid var(--rule); padding: 28px 0 40px; color: var(--muted); font-size: 0.9rem; }
.site-foot nav { display: flex; gap: 18px; flex-wrap: wrap; margin-bottom: 10px; }
.site-foot a { color: var(--muted); }

/* Type */
h1, h2, h3 { font-family: var(--serif); line-height: 1.2; letter-spacing: -0.01em; }
h1 { font-size: clamp(1.8rem, 4vw, 2.6rem); margin: 0 0 12px; }
h2 { font-size: 1.45rem; margin: 40px 0 12px; }
h3 { font-size: 1.1rem; margin: 24px 0 8px; }
.lede { font-size: 1.1rem; color: var(--muted); max-width: 680px; margin: 0 0 28px; }
.eyebrow { font: 500 0.78rem/1 var(--mono); text-transform: uppercase; letter-spacing: 0.08em; color: var(--accent); margin: 32px 0 10px; }
.crumbs { font-size: 0.88rem; color: var(--muted); margin: 24px 0 0; }
.crumbs a { color: var(--muted); }

/* Home */
.hero { padding: 48px 0 16px; }
.tool-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 16px; margin: 8px 0 0; padding: 0; list-style: none; }
.tool-card { display: block; height: 100%; background: var(--card); border: 1px solid var(--rule); border-radius: var(--radius); padding: 20px; text-decoration: none; color: var(--ink); transition: border-color .15s, transform .15s; }
.tool-card:hover { border-color: var(--accent); transform: translateY(-2px); }
.tool-card .tag { font: 500 0.72rem/1 var(--mono); text-transform: uppercase; letter-spacing: 0.08em; color: var(--accent); }
.tool-card h3 { margin: 10px 0 6px; }
.tool-card p { margin: 0; color: var(--muted); font-size: 0.95rem; }

/* Calculator layout */
.calc { display: grid; grid-template-columns: minmax(0, 1.25fr) minmax(0, 1fr); gap: 24px; align-items: start; }
@media (max-width: 820px) { .calc { grid-template-columns: 1fr; } }
.panel { background: var(--card); border: 1px solid var(--rule); border-radius: var(--radius); padding: 20px; }
fieldset { border: 0; padding: 0; margin: 0 0 20px; }
fieldset:last-of-type { margin-bottom: 8px; }
legend { font: 500 0.78rem/1 var(--mono); text-transform: uppercase; letter-spacing: 0.08em; color: var(--muted); padding: 0; margin-bottom: 12px; }
.fields { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px 14px; }
@media (max-width: 480px) { .fields { grid-template-columns: 1fr; } }
.field label { display: block; font-size: 0.88rem; font-weight: 500; margin-bottom: 4px; }
.field .hint { display: block; font-size: 0.78rem; color: var(--muted); margin-top: 3px; line-height: 1.35; }
.input { display: flex; align-items: center; border: 1px solid var(--rule); border-radius: 8px; background: var(--paper); overflow: hidden; }
.input:focus-within { border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-soft); }
.input input { flex: 1; min-width: 0; border: 0; background: transparent; color: var(--ink); font: 1rem var(--mono); padding: 9px 10px; outline: none; }
.input .affix { font: 0.9rem var(--mono); color: var(--muted); padding: 0 10px; }
.input .affix:first-child { padding-right: 0; }
.input .affix:last-child { padding-left: 0; }
.check { display: flex; gap: 8px; align-items: center; font-size: 0.9rem; grid-column: 1 / -1; }
.check input { width: 18px; height: 18px; accent-color: var(--accent); }

.results { position: sticky; top: 16px; }
.big { border-radius: 8px; padding: 16px; background: var(--accent-soft); margin-bottom: 14px; }
.big.is-neg { background: var(--neg-soft); }
.big .label { font-size: 0.85rem; color: var(--muted); }
.big .value { font: 600 2rem/1.15 var(--mono); color: var(--accent); margin-top: 4px; }
.big.is-neg .value { color: var(--neg); }
.big .sub { font-size: 0.82rem; color: var(--muted); margin-top: 4px; }
.kpis { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; margin-bottom: 14px; }
.kpi { border: 1px solid var(--rule); border-radius: 8px; padding: 10px 12px; }
.kpi .label { font-size: 0.78rem; color: var(--muted); }
.kpi .value { font: 600 1.15rem/1.3 var(--mono); }
.rows { width: 100%; border-collapse: collapse; font-size: 0.92rem; }
.rows td { padding: 7px 0; border-top: 1px solid var(--rule); }
.rows td:last-child { text-align: right; font-family: var(--mono); white-space: nowrap; padding-left: 12px; }
.note { font-size: 0.85rem; background: var(--accent-soft); border-radius: 8px; padding: 10px 12px; margin: 12px 0 0; }
.actions { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 14px; }
.btn { font: 500 0.88rem var(--sans); border-radius: 8px; padding: 9px 14px; cursor: pointer; border: 1px solid var(--accent); background: var(--accent); color: var(--accent-ink); }
.btn.ghost { background: transparent; color: var(--accent); }

/* Article content */
.prose { max-width: 720px; }
.prose p, .prose li { color: var(--ink); }
.formula { font: 0.9rem/1.6 var(--mono); background: var(--card); border: 1px solid var(--rule); border-left: 3px solid var(--accent); border-radius: 6px; padding: 12px 14px; overflow-x: auto; white-space: pre-wrap; }
details { border-top: 1px solid var(--rule); padding: 12px 0; }
details:last-of-type { border-bottom: 1px solid var(--rule); }
summary { cursor: pointer; font-weight: 600; }
details p { margin: 8px 0 0; color: var(--muted); }
.disclaimer { font-size: 0.85rem; color: var(--muted); border: 1px dashed var(--rule); border-radius: 8px; padding: 12px 14px; margin-top: 32px; }
.related { display: flex; gap: 10px; flex-wrap: wrap; padding: 0; list-style: none; }
.related a { display: inline-block; border: 1px solid var(--rule); border-radius: 999px; padding: 6px 14px; text-decoration: none; font-size: 0.9rem; background: var(--card); }

/* Placeholder for future ad units; hidden until ads are approved. */
.ad-slot { display: none; }

/* Compact result bar on phones, so results stay visible while editing inputs */
.mobile-bar { display: none; }
@media (max-width: 820px) {
  .mobile-bar { display: flex; align-items: center; gap: 10px; position: fixed; left: 0; right: 0; bottom: 0; z-index: 10;
    padding: 10px 16px calc(10px + env(safe-area-inset-bottom)); background: var(--card); border-top: 1px solid var(--rule);
    box-shadow: 0 -4px 16px rgba(0,0,0,.08); font-size: 0.85rem; color: var(--muted); }
  .mobile-bar strong { font: 600 1.15rem var(--mono); color: var(--accent); margin-left: auto; }
  .mobile-bar.is-neg strong { color: var(--neg); }
  .mobile-bar a { font-size: 0.85rem; }
  body { padding-bottom: 64px; }
  .results { position: static; }
}