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

:root {
  --bg: #f6f7fb;
  --card: #ffffff;
  --text: #1a1d29;
  --muted: #666b7a;
  --primary: #2f6fed;
  --primary-dark: #1f52c2;
  --accent: #16a34a;
  --border: #e4e6ee;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

.wrap {
  max-width: 880px;
  margin: 0 auto;
  padding: 0 20px;
}

/* Header */
.site-header {
  background: var(--card);
  border-bottom: 1px solid var(--border);
  padding: 16px 0;
}
.site-header .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.logo {
  font-size: 1.3rem;
  font-weight: 800;
  text-decoration: none;
  color: var(--text);
}
.logo .dot { color: var(--primary); }
.header-nav a {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.95rem;
}

/* Hero */
.hero {
  padding: 40px 0 12px;
  text-align: center;
}
.hero h1 {
  font-size: 1.9rem;
  margin-bottom: 10px;
}
.hero p {
  color: var(--muted);
  max-width: 640px;
  margin: 0 auto;
}

/* Calculator card */
.calc-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 28px;
  margin: 28px auto;
  max-width: 560px;
  box-shadow: 0 10px 30px rgba(20, 30, 60, 0.06);
}
.field {
  margin-bottom: 18px;
}
.field label {
  display: block;
  font-weight: 600;
  font-size: 0.92rem;
  margin-bottom: 6px;
}
.field input {
  width: 100%;
  padding: 12px 14px;
  border: 1px solid var(--border);
  border-radius: 10px;
  font-size: 1.05rem;
}
.field input:focus {
  outline: none;
  border-color: var(--primary);
}
.field .hint {
  font-size: 0.82rem;
  color: var(--muted);
  margin-top: 6px;
}
.field .hint a { color: var(--primary); }

.presets {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 8px;
}
.preset-btn {
  border: 1px solid var(--border);
  background: var(--bg);
  border-radius: 999px;
  padding: 6px 12px;
  font-size: 0.85rem;
  cursor: pointer;
  color: var(--text);
}
.preset-btn:hover { border-color: var(--primary); color: var(--primary); }

.calc-btn {
  width: 100%;
  padding: 14px;
  border: none;
  border-radius: 10px;
  background: var(--primary);
  color: #fff;
  font-size: 1.05rem;
  font-weight: 700;
  cursor: pointer;
  margin-top: 6px;
}
.calc-btn:hover { background: var(--primary-dark); }

.result {
  margin-top: 22px;
  padding: 18px;
  border-radius: 12px;
  background: #f0f6ff;
  border: 1px solid #d6e4ff;
  display: none;
}
.result.show { display: block; }
.result .row {
  display: flex;
  justify-content: space-between;
  padding: 6px 0;
  font-size: 0.98rem;
}
.result .row.total {
  border-top: 1px dashed #c3d6f7;
  margin-top: 6px;
  padding-top: 12px;
  font-weight: 800;
  font-size: 1.15rem;
  color: var(--primary-dark);
}
.result .warn {
  margin-top: 10px;
  font-size: 0.85rem;
  color: #b45309;
  background: #fffbeb;
  border: 1px solid #fde68a;
  padding: 8px 10px;
  border-radius: 8px;
}

/* Content sections */
.content {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 28px;
  margin: 24px auto;
  max-width: 720px;
}
.content h2 {
  font-size: 1.3rem;
  margin: 0 0 12px;
}
.content h2:not(:first-child) { margin-top: 26px; }
.content p { color: var(--text); margin-bottom: 10px; }
.content p.muted { color: var(--muted); font-size: 0.9rem; }

.faq-item { margin-bottom: 16px; }
.faq-item h3 { font-size: 1.02rem; margin-bottom: 4px; }
.faq-item p { color: var(--muted); }

/* Footer */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 26px 0 40px;
  margin-top: 20px;
}
.site-footer .wrap {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 10px;
  font-size: 0.85rem;
  color: var(--muted);
}
.site-footer .credit a { color: var(--primary); text-decoration: none; }
.foot-links a { color: var(--muted); text-decoration: none; margin-left: 14px; }

@media (max-width: 560px) {
  .calc-card, .content { padding: 20px; border-radius: 12px; }
  .hero h1 { font-size: 1.55rem; }
}