:root {
  --bg: #f4f8fb;
  --surface: #ffffff;
  --text: #0f172a;
  --muted: #475569;
  --line: #dbe3ee;
  --primary: #0f172a;
  --accent: #0f766e;
  --accent-soft: #d8f3ec;
  --gold: #d97706;
  --gold-soft: #fff4d6;
  --success: #047857;
  --danger: #b91c1c;
  --shadow: 0 18px 45px rgba(15, 23, 42, 0.08);
  --radius: 18px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: Inter, "IBM Plex Sans", system-ui, -apple-system, sans-serif;
  background:
    radial-gradient(circle at top left, rgba(15, 118, 110, 0.08), transparent 22%),
    radial-gradient(circle at top right, rgba(217, 119, 6, 0.10), transparent 26%),
    var(--bg);
  color: var(--text);
  line-height: 1.55;
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; }

.container {
  width: min(1100px, calc(100% - 1.5rem));
  margin: 0 auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  backdrop-filter: blur(14px);
  background: rgba(248, 250, 252, 0.88);
  border-bottom: 1px solid rgba(15, 23, 42, 0.08);
}

.navbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.9rem 0;
}
.brand {
  display: flex;
  align-items: center;
  gap: 0.7rem;
  font-weight: 800;
  letter-spacing: -0.02em;
}
.brand-mark {
  width: 40px;
  height: 40px;
  display: grid;
  place-items: center;
  border-radius: 12px;
  background: var(--primary);
  color: #fff;
  font-size: 1.1rem;
}
.nav-links {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  color: var(--muted);
}

.hero {
  padding: 2.2rem 0 1.2rem;
}
.hero-card {
  background: linear-gradient(135deg, #e8f7f4, #fef9ef 60%, #eef5ff);
  border: 1px solid rgba(15, 118, 110, 0.18);
  border-radius: 24px;
  padding: 1.4rem;
  box-shadow: var(--shadow);
}
.hero-badge {
  display: inline-flex;
  padding: 0.35rem 0.7rem;
  border-radius: 999px;
  background: rgba(15, 118, 110, 0.12);
  color: var(--accent);
  font-size: 0.84rem;
  font-weight: 800;
  margin-bottom: 0.9rem;
}
.hero-card h1 {
  margin: 0 0 0.5rem;
  font-size: clamp(1.85rem, 3vw, 2.9rem);
  line-height: 1.15;
  letter-spacing: -0.03em;
}
.hero-card p { margin: 0; color: var(--muted); }
.hero-pills {
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem;
  margin-top: 1rem;
}
.hero-pills span {
  padding: 0.42rem 0.7rem;
  border-radius: 999px;
  background: var(--surface);
  border: 1px solid rgba(15, 23, 42, 0.09);
  color: var(--primary);
  font-size: 0.86rem;
  font-weight: 700;
}

.grid {
  display: grid;
  gap: 1rem;
}
.grid-3 { grid-template-columns: repeat(3, minmax(0,1fr)); }
.grid-2 { grid-template-columns: repeat(2, minmax(0,1fr)); }

.card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.tool-card {
  display: flex;
  flex-direction: column;
  gap: 0.9rem;
  padding: 1.1rem;
  height: 100%;
}
.tool-card h3 { margin: 0; font-size: 1.1rem; }
.tool-card p { margin: 0; color: var(--muted); font-size: 0.96rem; }
.tool-meta {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  color: var(--accent);
  font-weight: 700;
}

.page-shell {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 1.2rem;
  padding: 1.2rem 0 2.5rem;
}
.page-card {
  padding: 1.15rem;
}

.calculator-form .field-row {
  display: grid;
  gap: 0.9rem;
}
.field {
  display: grid;
  gap: 0.35rem;
}
.field label {
  font-weight: 700;
  font-size: 0.95rem;
}
.field input,
.field select {
  width: 100%;
  padding: 0.9rem 0.95rem;
  border-radius: 14px;
  border: 1px solid var(--line);
  background: #fff;
  color: var(--text);
  font: inherit;
}
.field input:focus,
.field select:focus { outline: 2px solid rgba(15, 118, 110, 0.2); border-color: var(--accent); }

.helper-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  color: var(--muted);
  font-size: 0.9rem;
}
.error-text {
  min-height: 1.2rem;
  color: var(--danger);
  font-size: 0.84rem;
}
.result-panel {
  background: linear-gradient(180deg, #0f172a, #13213a);
  color: #fff;
  padding: 1rem;
  border-radius: 18px;
}
.result-panel h2 { margin: 0 0 0.9rem; font-size: 1rem; }
.result-figure {
  font-family: "SFMono-Regular", Consolas, monospace;
  font-weight: 800;
  font-size: clamp(1.8rem, 4vw, 2.8rem);
  letter-spacing: -0.03em;
  color: #fff;
}
.result-sub {
  display: flex;
  justify-content: space-between;
  gap: 0.75rem;
  font-size: 0.92rem;
  color: rgba(255,255,255,0.8);
}

.stat-grid {
  display: grid;
  gap: 0.9rem;
  grid-template-columns: repeat(2, minmax(0,1fr));
}
.stat-box {
  background: #f8fafc;
  border: 1px solid var(--line);
  padding: 0.8rem;
  border-radius: 14px;
}
.stat-box small { display: block; color: var(--muted); }
.stat-box strong { font-size: 1.15rem; }

.chart-wrap {
  margin-top: 1rem;
}
.chart-wrap svg { width: 100%; height: auto; }

.details-card {
  margin-top: 1rem;
  padding: 0.8rem 0.9rem;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: #f8fafc;
}

.seo-article {
  margin-top: 1.2rem;
  display: grid;
  gap: 1rem;
}

.seo-article h2,
.seo-article h3 {
  margin: 0 0 0.35rem;
  letter-spacing: -0.02em;
}

.seo-article p,
.seo-article li {
  color: var(--muted);
}

.info-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.85rem;
}

.info-card {
  background: #f8fafc;
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 0.95rem;
}

.info-card strong {
  display: block;
  margin-bottom: 0.25rem;
  color: var(--text);
}

.table-wrap {
  overflow-x: auto;
}

.table-wrap table {
  width: 100%;
  border-collapse: collapse;
}

.table-wrap th,
.table-wrap td {
  padding: 0.75rem;
  border-bottom: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}

.table-wrap th {
  background: #eff6ff;
  font-size: 0.92rem;
}

.faq-list {
  display: grid;
  gap: 0.75rem;
}

.faq-list details {
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 0.9rem 1rem;
  background: #fff;
}

.faq-list summary {
  font-weight: 800;
  cursor: pointer;
}

.faq-list p {
  margin: 0.7rem 0 0;
}

.accent-positive { color: var(--success); }
.accent-negative { color: var(--danger); }
.accent-warning { color: var(--warning); }

.search-bar {
  margin: 1rem 0 1.3rem;
  width: min(480px, 100%);
  padding: 0.9rem 1rem;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: white;
  font: inherit;
}
.empty-state {
  display: none;
  padding: 1rem;
  text-align: center;
  color: var(--muted);
}

footer {
  border-top: 1px solid rgba(15, 23, 42, 0.08);
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.5), rgba(230, 243, 247, 0.95));
  padding: 1.5rem 0 2rem;
  color: var(--muted);
}
.footer-grid {
  display: grid;
  gap: 0.85rem;
  grid-template-columns: 1.4fr 1fr;
  align-items: center;
}
.footer-grid strong {
  display: block;
  margin-bottom: 0.35rem;
  color: var(--primary);
}
.footer-grid p {
  margin: 0;
  font-size: 0.94rem;
}
.footer-links {
  text-align: right;
}

@media (max-width: 900px) {
  .page-shell,
  .grid-3,
  .grid-2,
  .footer-grid { grid-template-columns: 1fr; }
  .footer-links { text-align: left; }
}

@media (max-width: 640px) {
  .hero-card { padding: 1rem; }
  .page-card { padding: 1rem; }
  .navbar { flex-direction: column; align-items: stretch; }
  .nav-links { justify-content: center; }
}