:root {
  --navy: #0b1f33;
  --navy-2: #102b47;
  --teal: #0e9f6e;
  --teal-dark: #0b7d57;
  --bg: #f6f8fb;
  --card: #ffffff;
  --text: #1c2b3a;
  --muted: #5b6b7c;
  --line: #e3e9f0;
  --radius: 14px;
  --shadow: 0 8px 28px rgba(11, 31, 51, 0.08);
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  font-family: "Inter", "Segoe UI", system-ui, -apple-system, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  font-size: 16px;
}

.container { max-width: 1120px; margin: 0 auto; padding: 0 20px; }

a { color: var(--teal-dark); text-decoration: none; }
a:hover { text-decoration: underline; }

h1, h2, h3 { line-height: 1.25; color: var(--navy); }
h1 { font-size: 2.3rem; margin-bottom: 14px; }
h2 { font-size: 1.6rem; margin: 42px 0 14px; }
h3 { font-size: 1.15rem; margin: 24px 0 8px; }

p { margin-bottom: 14px; }

.site-header {
  background: var(--navy);
  color: #fff;
  position: sticky;
  top: 0;
  z-index: 50;
  box-shadow: var(--shadow);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: #fff;
  font-weight: 700;
  font-size: 1.05rem;
}
.brand:hover { text-decoration: none; }

.brand-mark {
  width: 34px;
  height: 34px;
  border-radius: 9px;
  background: linear-gradient(135deg, var(--teal), #2dd4bf);
  display: grid;
  place-items: center;
  font-size: 1rem;
  color: #06281c;
  font-weight: 800;
}

.nav-menu { display: flex; gap: 6px; list-style: none; }

.nav-menu a {
  color: #cfdcea;
  padding: 8px 12px;
  border-radius: 8px;
  font-size: 0.92rem;
}
.nav-menu a:hover { background: rgba(255, 255, 255, 0.08); color: #fff; text-decoration: none; }
.nav-menu a.active { background: rgba(255, 255, 255, 0.14); color: #fff; }

.nav-toggle {
  display: none;
  background: none;
  border: 1px solid rgba(255, 255, 255, 0.3);
  color: #fff;
  border-radius: 8px;
  padding: 6px 12px;
  font-size: 1rem;
  cursor: pointer;
}

.hero {
  background: linear-gradient(150deg, var(--navy) 0%, var(--navy-2) 55%, #0f3d33 100%);
  color: #eaf2f9;
  padding: 72px 0 64px;
}
.hero h1 { color: #fff; max-width: 720px; }
.hero p.lead { font-size: 1.15rem; color: #c8d8e8; max-width: 680px; }

.btn {
  display: inline-block;
  background: var(--teal);
  color: #fff;
  font-weight: 600;
  padding: 13px 26px;
  border-radius: 10px;
  font-size: 1rem;
  border: none;
  cursor: pointer;
  transition: background 0.15s ease, transform 0.15s ease;
}
.btn:hover { background: var(--teal-dark); text-decoration: none; transform: translateY(-1px); }

.btn-secondary {
  background: transparent;
  border: 1.5px solid rgba(255, 255, 255, 0.45);
  color: #fff;
  margin-left: 12px;
}
.btn-secondary:hover { background: rgba(255, 255, 255, 0.1); }

.section { padding: 56px 0; }

.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 22px; }

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 26px;
  box-shadow: var(--shadow);
}
.card h3 { margin-top: 0; }
.card .icon { font-size: 1.7rem; margin-bottom: 10px; }

.table-wrap { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; background: var(--card); border-radius: var(--radius); overflow: hidden; box-shadow: var(--shadow); }
th, td { text-align: left; padding: 13px 18px; border-bottom: 1px solid var(--line); font-size: 0.95rem; }
th { background: var(--navy); color: #fff; font-weight: 600; }
tr:last-child td { border-bottom: none; }
td.num { text-align: right; font-variant-numeric: tabular-nums; }

.calc-card { max-width: 560px; margin: 0 auto; }

.calc-row { display: flex; gap: 12px; margin-bottom: 16px; }

.field { flex: 1; display: flex; flex-direction: column; gap: 6px; }
.field label { font-size: 0.82rem; font-weight: 600; color: var(--muted); text-transform: uppercase; letter-spacing: 0.04em; }

.field input, .field select {
  padding: 12px 14px;
  border: 1.5px solid var(--line);
  border-radius: 10px;
  font-size: 1rem;
  background: #fbfcfe;
  color: var(--text);
  outline: none;
  width: 100%;
}
.field input:focus, .field select:focus { border-color: var(--teal); }

.flip-btn {
  align-self: flex-end;
  background: var(--navy);
  color: #fff;
  border: none;
  border-radius: 10px;
  width: 46px;
  height: 46px;
  font-size: 1.15rem;
  cursor: pointer;
  margin-bottom: 1px;
}
.flip-btn:hover { background: var(--navy-2); }

.calc-result { margin-top: 18px; padding-top: 18px; border-top: 1px solid var(--line); }
.calc-result.hidden { display: none; }

.calc-out {
  font-size: 2rem;
  font-weight: 800;
  color: var(--navy);
  word-break: break-all;
}

.calc-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 10px 22px; margin-top: 14px; font-size: 0.92rem; }
.calc-grid .label { color: var(--muted); }
.calc-grid .value { font-weight: 600; text-align: right; }
.calc-grid .value.ok { color: var(--teal-dark); }
.calc-grid .value.warn { color: #b45309; }
.calc-grid .value.bad { color: #b91c1c; }

.calc-status { margin-top: 14px; font-size: 0.82rem; color: var(--muted); }

.notice {
  background: #fff8ec;
  border: 1px solid #f2e3c4;
  border-radius: 10px;
  padding: 14px 18px;
  font-size: 0.9rem;
  color: #7a5c14;
  margin: 24px 0;
}

.page-head { background: var(--navy); color: #fff; padding: 52px 0; }
.page-head h1 { color: #fff; }
.page-head p { color: #c8d8e8; max-width: 760px; }

.content { max-width: 800px; }
.content ul, .content ol { margin: 0 0 16px 22px; }
.content li { margin-bottom: 8px; }

.cta-band {
  background: var(--navy);
  color: #fff;
  border-radius: var(--radius);
  padding: 38px;
  text-align: center;
  margin: 48px 0;
}
.cta-band h2 { color: #fff; margin-top: 0; }

.site-footer {
  background: var(--navy);
  color: #9fb4c8;
  margin-top: 72px;
  padding: 44px 0 30px;
  font-size: 0.88rem;
}
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 32px; margin-bottom: 28px; }
.site-footer h4 { color: #fff; font-size: 0.95rem; margin-bottom: 12px; }
.site-footer a { color: #9fb4c8; }
.site-footer a:hover { color: #fff; }
.site-footer ul { list-style: none; }
.site-footer li { margin-bottom: 7px; }
.footer-bottom { border-top: 1px solid rgba(255, 255, 255, 0.12); padding-top: 20px; font-size: 0.8rem; }

.breadcrumb { font-size: 0.85rem; color: #9fb4c8; margin-bottom: 10px; }
.breadcrumb a { color: #9fb4c8; }

@media (max-width: 860px) {
  .grid-3, .grid-2 { grid-template-columns: 1fr; }
  .nav-toggle { display: block; }
  .nav-menu {
    display: none;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: var(--navy-2);
    flex-direction: column;
    padding: 12px 20px 18px;
  }
  .nav-menu.open { display: flex; }
  h1 { font-size: 1.8rem; }
  .footer-grid { grid-template-columns: 1fr; }
  .calc-row { flex-wrap: wrap; }
}