:root {
  --ink: #16232e;
  --dim: #5a6b76;
  --line: #d9e2e8;
  --bg: #f6f8f9;
  --card: #ffffff;
  --accent: #0b6e4f;
  --accent-ink: #ffffff;
  --warn-bg: #fff6e0;
  --warn-line: #e5c15c;
  --warn-ink: #6b5310;
  --ok-bg: #e8f5ee;
  --big: #b3540e;
  --radius: 12px;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0; background: var(--bg); color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  font-size: 17px; line-height: 1.65;
}
a { color: var(--accent); }
h1 { font-size: 2rem; line-height: 1.2; margin: 0.4em 0 0.35em; letter-spacing: -0.01em; }
h2 { font-size: 1.35rem; margin: 1.5em 0 0.5em; scroll-margin-top: 84px; }
h3 { font-size: 1.1rem; margin: 1.2em 0 0.4em; }
p { margin: 0.6em 0; }
.small { font-size: 0.86rem; }
.dim { color: var(--dim); }
.lede { font-size: 1.12rem; color: #33454f; }

.topbar {
  position: sticky; top: 0; z-index: 50;
  display: flex; align-items: center; gap: 1.2rem;
  height: 54px; padding: 0 16px;
  background: rgba(255,255,255,0.96); border-bottom: 1px solid var(--line);
  backdrop-filter: blur(6px);
}
.brand { font-weight: 800; font-size: 1.12rem; color: var(--ink); text-decoration: none; letter-spacing: -0.01em; }
.brand span { color: var(--accent); }
.brand.foot { font-size: 1rem; }
.topnav { display: flex; gap: 1.1rem; margin-left: auto; }
.topnav a { color: var(--ink); text-decoration: none; font-size: 0.98rem; padding: 4px 2px; }
.topnav a:hover { color: var(--accent); }
.topnav a[aria-current="page"] { color: var(--accent); font-weight: 700; border-bottom: 2px solid var(--accent); }
.menubtn {
  display: none; margin-left: auto; font: inherit; font-size: 0.95rem;
  background: var(--card); border: 1px solid var(--line); border-radius: 8px; padding: 5px 14px; cursor: pointer;
}
.navpop { border: 1px solid var(--line); border-radius: var(--radius); padding: 10px; box-shadow: 0 12px 32px rgba(20,40,55,.18); }
.navpop nav { display: flex; flex-direction: column; gap: 4px; }
.navpop a { color: var(--ink); text-decoration: none; padding: 8px 10px; border-radius: 8px; font-size: 1rem; }
.navpop a:hover { background: var(--bg); }
@media (max-width: 640px) {
  .topnav { display: none; }
  .menubtn { display: block; }
  h1 { font-size: 1.65rem; }
}

main { max-width: 880px; margin: 0 auto; padding: 18px 16px 30px; }
section { scroll-margin-top: 84px; }

.banner {
  background: var(--warn-bg); border: 1px solid var(--warn-line); color: var(--warn-ink);
  border-radius: var(--radius); padding: 10px 14px; font-size: 0.95rem; margin: 6px 0 16px;
}
.banner.ok { background: var(--ok-bg); border-color: #9fd3b4; color: #14532d; }

.bignum {
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 18px 20px; margin: 14px 0; display: flex; flex-wrap: wrap; gap: 8px 28px; align-items: baseline;
}
.bignum .v { font-size: 2.6rem; font-weight: 800; color: var(--big); line-height: 1; }
.bignum .k { font-weight: 600; }
.bignum .sub { color: var(--dim); font-size: 0.95rem; flex-basis: 100%; }

.grid { display: grid; gap: 12px; }
.grid.c3 { grid-template-columns: repeat(3, 1fr); }
@media (max-width: 720px) { .grid.c3 { grid-template-columns: 1fr; } }
.card {
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 16px 18px; text-decoration: none; color: var(--ink); display: block;
}
a.card:hover { border-color: var(--accent); }
.card .t { font-weight: 700; font-size: 1.08rem; margin-bottom: 4px; }
.card p { color: var(--dim); font-size: 0.95rem; margin: 4px 0 0; }

.tablewrap { overflow-x: auto; border: 1px solid var(--line); border-radius: var(--radius); background: var(--card); margin: 12px 0; }
table { border-collapse: collapse; width: 100%; min-width: 620px; font-size: 0.97rem; }
th, td { padding: 9px 12px; text-align: left; border-bottom: 1px solid var(--line); vertical-align: top; }
th { background: #eef3f5; font-weight: 700; white-space: nowrap; }
tr:last-child td { border-bottom: none; }
td.num, th.num { text-align: right; font-variant-numeric: tabular-nums; white-space: nowrap; }
.alt { color: var(--warn-ink); font-size: 0.88em; }

.callout { background: #eef6f2; border: 1px solid #bcdcc9; border-radius: var(--radius); padding: 12px 16px; margin: 14px 0; }
.callout.warn { background: var(--warn-bg); border-color: var(--warn-line); color: var(--warn-ink); }

form.calc { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 18px 20px; margin: 14px 0; }
.field { margin-bottom: 16px; }
.field label, .field .flabel { display: block; font-weight: 600; margin-bottom: 6px; }
.field .hint { color: var(--dim); font-size: 0.88rem; font-weight: 400; }
input[type="number"], input[type="text"] {
  font: inherit; font-size: 1.05rem; padding: 9px 12px; border: 1px solid #b9c7cf; border-radius: 8px; width: 100%; max-width: 320px;
}
input[aria-invalid="true"] { border-color: #c0392b; outline: 2px solid rgba(192,57,43,.25); }
.seg { display: flex; flex-wrap: wrap; gap: 8px; }
.seg label {
  border: 1px solid #b9c7cf; border-radius: 999px; padding: 6px 14px; cursor: pointer; font-weight: 500; margin: 0;
}
.seg input { position: absolute; opacity: 0; }
.seg label:has(input:checked) { background: var(--accent); color: var(--accent-ink); border-color: var(--accent); font-weight: 700; }
.seg label:has(input:focus-visible) { outline: 2px solid var(--accent); outline-offset: 2px; }
.btn {
  font: inherit; font-weight: 700; background: var(--accent); color: var(--accent-ink);
  border: none; border-radius: 8px; padding: 11px 22px; cursor: pointer;
}
.btn:hover { filter: brightness(1.08); }
.err { color: #c0392b; font-size: 0.92rem; min-height: 1.2em; margin-top: 6px; }
.result { margin-top: 18px; border-top: 1px solid var(--line); padding-top: 14px; }
.result .headline { font-size: 1.25rem; font-weight: 800; }
.result .rows { display: grid; gap: 6px; margin-top: 8px; }
.result .row { display: flex; justify-content: space-between; gap: 16px; border-bottom: 1px dashed var(--line); padding: 5px 0; }
.result .row .rv { font-variant-numeric: tabular-nums; font-weight: 600; white-space: nowrap; }
.cliff { font-size: 1.05rem; }
footer { border-top: 1px solid var(--line); background: var(--card); margin-top: 20px; }
.footgrid { max-width: 880px; margin: 0 auto; padding: 22px 16px 6px; display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 20px; }
@media (max-width: 720px) { .footgrid { grid-template-columns: 1fr; } }
.footgrid nav { display: flex; flex-direction: column; gap: 6px; }
.footgrid nav a { color: var(--ink); text-decoration: none; font-size: 0.95rem; }
.footgrid nav a:hover { color: var(--accent); }
footer > .small { max-width: 880px; margin: 0 auto; padding: 0 16px 20px; }