:root {
  --ink: #14213d;
  --ink-soft: #44526e;
  --accent: #0b6e4f;
  --accent-dark: #08543c;
  --bg: #f7f9fb;
  --card: #ffffff;
  --line: #e3e8ef;
  --gold: #fca311;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
body {
  font-family: "Segoe UI", system-ui, -apple-system, Arial, sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.65;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
.container { max-width: 1080px; margin: 0 auto; padding: 0 20px; }
.container.narrow { max-width: 780px; }

/* header */
.site-header { background: #fff; border-bottom: 1px solid var(--line); position: sticky; top: 0; z-index: 10; }
.header-inner { display: flex; align-items: center; justify-content: space-between; height: 58px; }
.brand { font-weight: 700; font-size: 1.15rem; color: var(--ink); }
.brand:hover { text-decoration: none; }
.nav a { margin-left: 22px; color: var(--ink-soft); font-weight: 500; }

/* hero */
.hero { background: linear-gradient(135deg, #0b6e4f 0%, #14213d 100%); color: #fff; padding: 64px 0 56px; }
.hero h1 { font-size: 2.4rem; margin-bottom: 12px; }
.hero-sub { max-width: 640px; font-size: 1.08rem; opacity: 0.92; }
.hero-stats { display: flex; flex-wrap: wrap; gap: 28px; margin-top: 24px; }
.hero-stats span { font-size: 0.95rem; opacity: 0.9; }
.hero-stats strong { display: block; font-size: 1.6rem; color: var(--gold); }

/* sections & cards */
.section { padding: 42px 0 10px; }
.section h2 { font-size: 1.55rem; margin-bottom: 18px; }
.cat-label { margin: 22px 0 10px; color: var(--ink-soft); font-size: 1.02rem; text-transform: uppercase; letter-spacing: 0.04em; }
.calc-filter { width: 100%; max-width: 520px; padding: 12px 16px; border: 1px solid var(--line); border-radius: 10px; font-size: 1rem; margin-bottom: 8px; background: #fff; color: var(--ink); }
.calc-filter:focus { outline: 2px solid var(--accent); border-color: var(--accent); }
.calc-noresults { color: var(--ink-soft); font-size: 0.95rem; margin: 8px 0; }
.cat-count { display: inline-block; background: var(--line); color: var(--ink-soft); font-size: 0.72rem; font-weight: 700; border-radius: 999px; padding: 1px 9px; margin-left: 6px; vertical-align: middle; }
.grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 14px; }
.card {
  background: var(--card); border: 1px solid var(--line); border-radius: 10px;
  padding: 16px 16px 14px; display: flex; flex-direction: column; gap: 6px;
  transition: transform 0.12s ease, box-shadow 0.12s ease;
}
.card:hover { transform: translateY(-2px); box-shadow: 0 6px 18px rgba(20, 33, 61, 0.08); text-decoration: none; }
.card-emoji { font-size: 1.5rem; }
.card-title { font-weight: 650; color: var(--ink); }
.card-desc { color: var(--ink-soft); font-size: 0.9rem; }

/* why */
.why { padding-bottom: 56px; }
.why-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 22px; }
.why-grid h3 { margin-bottom: 6px; font-size: 1.05rem; }
.why-grid p { color: var(--ink-soft); font-size: 0.95rem; }

/* calculator page */
.breadcrumb { margin: 20px 0 6px; font-size: 0.88rem; color: var(--ink-soft); }
h1 { font-size: 1.9rem; margin: 8px 0 10px; }
.lead { color: var(--ink-soft); font-size: 1.05rem; margin-bottom: 20px; }
.calc-box {
  background: var(--card); border: 1px solid var(--line); border-radius: 12px;
  padding: 24px; margin-bottom: 34px; box-shadow: 0 2px 10px rgba(20, 33, 61, 0.05);
}
.field { display: block; margin-bottom: 14px; }
.field-label { display: block; font-weight: 600; font-size: 0.94rem; margin-bottom: 5px; }
.hint { color: var(--ink-soft); font-weight: 400; font-style: normal; font-size: 0.85rem; }
.field input, .field select {
  width: 100%; padding: 10px 12px; border: 1px solid var(--line); border-radius: 8px;
  font-size: 1rem; background: #fff; color: var(--ink);
}
.field input:focus, .field select:focus { outline: 2px solid var(--accent); border-color: var(--accent); }
.btn {
  background: var(--accent); color: #fff; border: none; border-radius: 8px;
  padding: 12px 26px; font-size: 1.02rem; font-weight: 600; cursor: pointer; margin-top: 4px;
}
.btn:hover { background: var(--accent-dark); }
.result { margin-top: 18px; display: none; }
.result.show { display: block; }
.result-main {
  font-size: 1.7rem; font-weight: 700; color: var(--accent-dark);
  padding: 14px 18px; background: #eef7f3; border-radius: 10px; margin-bottom: 12px;
}
.result-main small { display: block; font-size: 0.85rem; font-weight: 500; color: var(--ink-soft); }
.result table { width: 100%; border-collapse: collapse; font-size: 0.95rem; }
.result td { padding: 7px 10px; border-bottom: 1px solid var(--line); }
.result td:last-child { text-align: right; font-weight: 600; }

/* explainer / article */
.explainer h2 { font-size: 1.35rem; margin: 28px 0 10px; }
.explainer h3 { font-size: 1.1rem; margin: 20px 0 8px; }
.explainer p { margin-bottom: 12px; }
.explainer ul, .explainer ol { margin: 0 0 12px 22px; }
.explainer li { margin-bottom: 6px; }
.explainer table { width: 100%; border-collapse: collapse; margin: 14px 0; font-size: 0.94rem; }
.explainer th, .explainer td { border: 1px solid var(--line); padding: 8px 10px; text-align: left; }
.explainer th { background: #eef2f6; }
.explainer code { background: #eef2f6; padding: 2px 6px; border-radius: 4px; font-size: 0.9em; }
.article-meta { color: var(--ink-soft); font-size: 0.88rem; margin-bottom: 18px; }
.toc { background: #f0f4f7; border: 1px solid var(--line); border-radius: 10px; padding: 12px 18px; margin: 0 0 22px; }
.toc summary { font-weight: 700; cursor: pointer; color: var(--ink); }
.toc ul { margin: 10px 0 4px 18px; }
.toc li { margin-bottom: 4px; font-size: 0.95rem; }
.toc a { color: var(--accent); }
.article-page { margin-top: 10px; }

/* faq */
.faq { margin: 34px 0; }
.faq h2 { font-size: 1.35rem; margin-bottom: 12px; }
.faq details { background: var(--card); border: 1px solid var(--line); border-radius: 8px; padding: 12px 16px; margin-bottom: 8px; }
.faq summary { font-weight: 600; cursor: pointer; }
.faq details p { margin-top: 8px; color: var(--ink-soft); }

/* related */
.related { margin: 30px 0 20px; }
.related h2 { font-size: 1.25rem; margin-bottom: 12px; }

.page-disclaimer { color: var(--ink-soft); font-size: 0.82rem; margin: 26px 0 40px; }

/* footer */
.site-footer { background: #14213d; color: #cdd5e0; margin-top: 40px; padding: 34px 0 20px; }
.footer-inner { display: flex; flex-wrap: wrap; gap: 40px; margin-bottom: 18px; }
.footer-col { max-width: 420px; display: flex; flex-direction: column; gap: 6px; }
.footer-col a { color: #9fb3c8; }
.footer-col p { font-size: 0.9rem; }
.disclaimer p { font-size: 0.78rem; color: #7d8ba1; border-top: 1px solid #2a3a5c; padding-top: 16px; }

@media (max-width: 640px) {
  .hero h1 { font-size: 1.7rem; }
  .nav a { margin-left: 14px; font-size: 0.92rem; }
}