:root {
  --bg: #0f1115;
  --bg-soft: #171b22;
  --text: #f4f7ff;
  --text-muted: #b9c3d8;
  --brand: #6b8cff;
  --brand-soft: #273a78;
  --accent: #26c281;
  --border: #2a3244;
  --max-width: 1120px;
  --shadow: 0 16px 32px rgba(0, 0, 0, 0.22);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: Inter, Segoe UI, Roboto, Arial, sans-serif;
  background: radial-gradient(circle at top, #141a2a 0%, var(--bg) 45%);
  color: var(--text);
  line-height: 1.6;
}

a {
  color: #9db4ff;
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

img {
  max-width: 100%;
  height: auto;
  border-radius: 10px;
}

.container {
  width: min(var(--max-width), 92%);
  margin: 0 auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  backdrop-filter: blur(8px);
  background: rgba(15, 17, 21, 0.88);
  border-bottom: 1px solid var(--border);
}

.header-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  padding: 14px 0;
}

.brand {
  font-weight: 700;
  font-size: 1.2rem;
  color: #eef2ff;
}

.nav-links {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  font-size: 0.95rem;
}

.hero {
  padding: 56px 0 32px;
}

.hero h1 {
  font-size: clamp(2rem, 4vw, 3rem);
  line-height: 1.2;
  margin: 0 0 16px;
}

.hero p {
  margin: 0;
  color: var(--text-muted);
  max-width: 840px;
}

.eyebrow {
  display: inline-block;
  margin-bottom: 14px;
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 6px 12px;
  font-size: 0.85rem;
  color: #dce5ff;
  background: rgba(107, 140, 255, 0.1);
}

.grid {
  display: grid;
  gap: 18px;
}

.stats-grid {
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  margin: 24px 0;
}

.card {
  background: linear-gradient(160deg, rgba(39, 58, 120, 0.2), rgba(23, 27, 34, 0.95));
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 18px;
  box-shadow: var(--shadow);
}

.card h3,
.card h2 {
  margin-top: 0;
}

.kpi-value {
  display: block;
  font-size: 1.55rem;
  font-weight: 700;
  margin-bottom: 4px;
}

.muted {
  color: var(--text-muted);
}

.section {
  padding: 28px 0;
}

.section h2 {
  margin-bottom: 8px;
}

.chart-wrap {
  position: relative;
  min-height: 320px;
}

.chart-wrap canvas {
  display: block;
  width: 100% !important;
  height: 280px !important;
}

.controls {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
  margin-bottom: 18px;
}

input[type="range"] {
  width: 260px;
}

input[type="number"],
input[type="text"],
select {
  width: 100%;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: #10151f;
  color: var(--text);
  padding: 10px 12px;
  font: inherit;
}

label {
  display: block;
  margin-bottom: 6px;
  font-weight: 600;
  color: #dce5ff;
}

.calculator-grid {
  grid-template-columns: 1.2fr 1fr;
  align-items: start;
}

.calculator-form {
  display: grid;
  gap: 14px;
}

.form-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(190px, 1fr));
  gap: 12px;
}

.result-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
  gap: 10px;
  margin-top: 14px;
}

.result-card {
  border: 1px solid var(--border);
  background: rgba(10, 16, 28, 0.6);
  border-radius: 10px;
  padding: 12px;
}

.result-card .label {
  display: block;
  color: var(--text-muted);
  font-size: 0.85rem;
}

.result-card .value {
  display: block;
  margin-top: 4px;
  font-size: 1.12rem;
  font-weight: 700;
  color: #eff3ff;
}

.formula-box {
  border-left: 4px solid var(--brand);
  background: rgba(39, 58, 120, 0.24);
  border-radius: 8px;
  padding: 10px 12px;
  margin-top: 12px;
}

.assumption-list li,
.caveat-list li {
  margin-bottom: 7px;
}

table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 16px;
  font-size: 0.95rem;
}

th,
td {
  border: 1px solid var(--border);
  padding: 10px;
  text-align: left;
}

th {
  background: #202635;
}

.highlight {
  color: #dce5ff;
  font-weight: 600;
}

.image-grid {
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  align-items: start;
}

figure {
  margin: 0;
}

figcaption {
  font-size: 0.86rem;
  color: var(--text-muted);
  margin-top: 8px;
}

.faq-item {
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--bg-soft);
  padding: 14px;
}

.faq-item summary {
  cursor: pointer;
  font-weight: 600;
}

.footer {
  margin-top: 28px;
  border-top: 1px solid var(--border);
  padding: 28px 0 42px;
  color: var(--text-muted);
  font-size: 0.92rem;
}

.footer-layout {
  display: grid;
  gap: 20px;
  grid-template-columns: minmax(220px, 1.2fr) repeat(3, minmax(180px, 1fr));
}

.footer-about h2,
.footer-group h2 {
  margin-top: 0;
  margin-bottom: 10px;
  font-size: 1rem;
  color: #e8eeff;
}

.footer-meta {
  color: #c9d4ef;
}

.footer-link-list {
  margin: 0;
  padding-left: 18px;
}

.footer-link-list li {
  margin-bottom: 6px;
}

.footer-bottom {
  margin-top: 20px;
  padding-top: 14px;
  border-top: 1px solid var(--border);
}

.pill-links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.pill-links a {
  display: inline-block;
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 8px 12px;
  background: rgba(38, 194, 129, 0.1);
  color: #d9ffee;
}

.sources-list li {
  margin-bottom: 8px;
}

.two-col {
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
}

@media (max-width: 720px) {
  .header-inner {
    flex-direction: column;
    align-items: flex-start;
  }

  .hero {
    padding-top: 32px;
  }

  .chart-wrap {
    min-height: 260px;
  }

  .chart-wrap canvas {
    height: 220px !important;
  }

  .calculator-grid {
    grid-template-columns: 1fr;
  }

  .footer-layout {
    grid-template-columns: 1fr;
  }
}