:root {
  --bg: #ffffff;
  --text: #111827;
  --muted: #6b7280;
  --border: #e5e7eb;
  --card: #ffffff;
  --shadow: 0 1px 2px rgba(0,0,0,.06);
  --radius: 14px;
  --max: 860px;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, "Apple Color Emoji", "Segoe UI Emoji";
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
}

a { color: inherit; text-decoration: none; }
a:hover { text-decoration: underline; }

.container {
  max-width: var(--max);
  margin: 0 auto;
  padding: 22px 16px 48px;
}

.header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 14px;
  padding: 6px 0 18px;
}

.brand {
  font-weight: 800;
  letter-spacing: -0.02em;
}
.brand span { color: var(--muted); font-weight: 700; }

.nav {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  font-size: 14px;
  color: var(--muted);
}
.nav a { padding: 6px 10px; border: 1px solid var(--border); border-radius: 999px; }
.nav a:hover { background: #f9fafb; text-decoration: none; }

.hero h1 {
  font-size: 32px;
  line-height: 1.15;
  margin: 8px 0 10px;
  letter-spacing: -0.03em;
}
.hero p { color: var(--muted); margin: 0 0 18px; max-width: 65ch; }

.grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0,1fr));
  gap: 12px;
}
@media (max-width: 720px) {
  .grid { grid-template-columns: 1fr; }
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 16px;
}

.card h2 {
  font-size: 16px;
  margin: 0 0 6px;
}
.card p {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
}

.tool {
  display: grid;
  gap: 12px;
}

.tool-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0,1fr));
  gap: 12px;
}
@media (max-width: 720px) {
  .tool-grid { grid-template-columns: 1fr; }
}

label {
  display: block;
  font-size: 13px;
  color: var(--muted);
  margin-bottom: 6px;
}

input, select {
  width: 100%;
  padding: 12px 12px;
  border: 1px solid var(--border);
  border-radius: 12px;
  font-size: 16px;
  outline: none;
}
input:focus, select:focus {
  border-color: #cbd5e1;
  box-shadow: 0 0 0 4px rgba(148,163,184,.15);
}

.result {
  padding: 14px;
  border: 1px dashed var(--border);
  border-radius: 12px;
  background: #fafafa;
}
.result strong { font-size: 18px; }

.section h3 {
  font-size: 16px;
  margin: 18px 0 8px;
}
.section p, .section li {
  color: var(--muted);
  font-size: 14px;
}
.section ul { margin: 8px 0 0 18px; }

.table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
  overflow: hidden;
  border-radius: 12px;
  border: 1px solid var(--border);
}
.table th, .table td {
  padding: 10px 12px;
  border-bottom: 1px solid var(--border);
}
.table th { text-align: left; background: #f9fafb; color: #374151; }
.table tr:last-child td { border-bottom: none; }

.footer {
  margin-top: 28px;
  padding-top: 18px;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 13px;
}

.ad {
  border: 1px dashed var(--border);
  border-radius: 12px;
  padding: 14px;
  color: var(--muted);
  font-size: 13px;
  background: #ffffff;
}
.small { font-size: 13px; color: var(--muted); }