:root {
  --bg: #0b1020;
  --panel: #ffffff;
  --ink: #1a2233;
  --muted: #5b6b86;
  --brand: #3b5bdb;
  --brand-2: #7048e8;
  --accent: #12b886;
  --ring: rgba(59, 91, 219, 0.35);
  --border: #e6e9f0;
  --shadow: 0 10px 30px rgba(16, 24, 40, 0.08);
}

* { box-sizing: border-box; }

html, body { margin: 0; padding: 0; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--ink);
  background: #f5f7fb;
  line-height: 1.55;
}

.wrap { width: min(960px, 92vw); margin-inline: auto; }

/* Header */
.site-header {
  background: linear-gradient(135deg, var(--brand), var(--brand-2));
  color: #fff;
}
.site-header .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 18px 0;
}
.brand { font-weight: 800; font-size: 1.25rem; color: #fff; text-decoration: none; letter-spacing: -0.02em; }
.brand span { opacity: 0.8; font-weight: 500; }
.site-header nav a {
  color: #eef1ff; text-decoration: none; margin-left: 18px; font-size: 0.95rem; opacity: 0.9;
}
.site-header nav a[aria-current="page"], .site-header nav a:hover { opacity: 1; text-decoration: underline; }

/* Hero */
.hero { padding: 40px 0 8px; }
.hero h1 { font-size: clamp(1.8rem, 4vw, 2.6rem); margin: 0 0 8px; letter-spacing: -0.03em; }
.lede { font-size: 1.1rem; color: var(--muted); margin: 0; max-width: 60ch; }

/* Card */
.card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 16px;
  box-shadow: var(--shadow);
  padding: 24px;
  margin: 24px 0;
}

/* Tool */
.tool-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr) auto;
  gap: 16px;
  align-items: end;
}
.field { display: flex; flex-direction: column; gap: 6px; }
.field label { font-size: 0.85rem; font-weight: 600; color: var(--muted); }
.field input {
  width: 100%; padding: 12px 14px; font-size: 1rem; border: 1px solid var(--border);
  border-radius: 10px; background: #fff; color: var(--ink);
}
.field input:focus { outline: none; border-color: var(--brand); box-shadow: 0 0 0 4px var(--ring); }
.input-affix { display: flex; align-items: center; border: 1px solid var(--border); border-radius: 10px; overflow: hidden; background: #fff; }
.input-affix:focus-within { border-color: var(--brand); box-shadow: 0 0 0 4px var(--ring); }
.input-affix span { padding: 0 12px; color: var(--muted); background: #f2f4f9; align-self: stretch; display: flex; align-items: center; }
.input-affix input { border: 0; border-radius: 0; }
.input-affix input:focus { box-shadow: none; }

.btn {
  background: linear-gradient(135deg, var(--brand), var(--brand-2));
  color: #fff; border: 0; border-radius: 10px; padding: 13px 22px; font-size: 1rem;
  font-weight: 700; cursor: pointer; transition: transform 0.06s ease, filter 0.15s ease;
}
.btn:hover { filter: brightness(1.05); }
.btn:active { transform: translateY(1px); }

/* Result */
.result { margin-top: 22px; border-top: 1px dashed var(--border); padding-top: 20px; }
.result-primary { display: flex; flex-direction: column; align-items: center; gap: 4px; margin-bottom: 18px; }
.result-label { color: var(--muted); font-size: 0.9rem; }
.result-value { font-size: clamp(2rem, 6vw, 3rem); font-weight: 800; color: var(--accent); letter-spacing: -0.02em; }
.result-breakdown { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; margin: 0; }
.result-breakdown div { background: #f7f9fc; border: 1px solid var(--border); border-radius: 10px; padding: 12px; text-align: center; }
.result-breakdown dt { color: var(--muted); font-size: 0.8rem; margin-bottom: 4px; }
.result-breakdown dd { margin: 0; font-weight: 700; font-size: 1.1rem; }
.error { color: #e03131; font-weight: 600; margin-top: 14px; }

/* Content */
.explainer { padding: 8px 0 40px; }
.explainer h2 { letter-spacing: -0.02em; }
.explainer a { color: var(--brand); }

/* Content pages */
.article { padding: 24px 0 48px; }
.article h1 { letter-spacing: -0.03em; }
.article a { color: var(--brand); }
.compare-table { width: 100%; border-collapse: collapse; margin: 20px 0; background: #fff; border-radius: 12px; overflow: hidden; box-shadow: var(--shadow); }
.compare-table th, .compare-table td { padding: 12px 14px; text-align: left; border-bottom: 1px solid var(--border); }
.compare-table th { background: #f2f4f9; font-size: 0.85rem; color: var(--muted); }

/* Footer */
.site-footer { border-top: 1px solid var(--border); background: #fff; margin-top: 24px; }
.site-footer .wrap { padding: 20px 0; color: var(--muted); font-size: 0.9rem; }

@media (max-width: 720px) {
  .tool-grid { grid-template-columns: 1fr 1fr; }
  .tool-grid .btn { grid-column: 1 / -1; }
  .result-breakdown { grid-template-columns: 1fr; }
}