/* ============================================
   EasyCalc - Site-wide Unified Styles
   ============================================ */
:root {
  --primary: #2563eb;
  --primary-dark: #1e40af;
  --primary-light: #eff6ff;
  --bg: #f4f6fb;
  --card: #ffffff;
  --text: #1f2937;
  --muted: #64748b;
  --border: #e2e8f0;
  --danger: #dc2626;
  --success: #16a34a;
  --radius: 12px;
  --shadow: 0 2px 10px rgba(15, 23, 42, 0.06);
}

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

html { -webkit-text-size-adjust: 100%; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  font-size: 16px;
}

.container { max-width: 1080px; margin: 0 auto; padding: 0 16px; }

a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ---------- Header navigation ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--card);
  box-shadow: 0 1px 4px rgba(15, 23, 42, 0.08);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}
.logo {
  font-size: 20px;
  font-weight: 700;
  color: var(--primary);
  display: flex;
  align-items: center;
  gap: 8px;
}
.logo:hover { text-decoration: none; }

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}
.nav-toggle span {
  display: block;
  height: 2px;
  width: 22px;
  background: var(--text);
  border-radius: 2px;
  transition: transform 0.25s, opacity 0.25s;
}
.nav-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

.site-nav ul {
  display: flex;
  gap: 4px;
  list-style: none;
}
.site-nav a {
  display: block;
  padding: 8px 14px;
  border-radius: 8px;
  color: var(--text);
  font-size: 15px;
}
.site-nav a:hover { background: var(--primary-light); text-decoration: none; }
.site-nav a.active { background: var(--primary); color: #fff; }

/* ---------- Homepage Hero ---------- */
.hero {
  background: linear-gradient(135deg, #2563eb 0%, #1e40af 100%);
  color: #fff;
  padding: 56px 0 48px;
  text-align: center;
}
.hero h1 { font-size: 32px; margin-bottom: 12px; }
.hero p { font-size: 17px; opacity: 0.9; max-width: 640px; margin: 0 auto; }

/* ---------- Tool card grid ---------- */
.tool-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(230px, 1fr));
  gap: 16px;
  margin: 24px 0 40px;
}
.tool-card {
  background: var(--card);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 22px 20px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  transition: transform 0.2s, box-shadow 0.2s;
  color: var(--text);
}
.tool-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 20px rgba(37, 99, 235, 0.15);
  text-decoration: none;
}
.tool-icon {
  width: 46px;
  height: 46px;
  border-radius: 10px;
  background: var(--primary-light);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 24px;
}
.tool-card h3 { font-size: 17px; }
.tool-card p { font-size: 14px; color: var(--muted); flex: 1; }
.tool-card .tool-link { font-size: 14px; color: var(--primary); font-weight: 500; }

/* ---------- Features section ---------- */
.features { margin: 0 0 40px; }
.features h2 { text-align: center; font-size: 24px; margin-bottom: 20px; }
.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 16px;
}
.feature-item {
  background: var(--card);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 20px;
  text-align: center;
}
.feature-item .fi-icon { font-size: 28px; margin-bottom: 8px; }
.feature-item h3 { font-size: 16px; margin-bottom: 4px; }
.feature-item p { font-size: 14px; color: var(--muted); }

/* ---------- Breadcrumb ---------- */
.breadcrumb {
  padding: 16px 0 4px;
  font-size: 14px;
  color: var(--muted);
}
.breadcrumb a { color: var(--muted); }
.breadcrumb a:hover { color: var(--primary); }

/* ---------- Tool page main ---------- */
.page-title { font-size: 26px; margin: 8px 0 6px; }
.page-desc { color: var(--muted); margin-bottom: 20px; font-size: 15px; }

.tool-card-box {
  background: var(--card);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 24px;
  margin-bottom: 24px;
}

.form-row { margin-bottom: 16px; }
.form-row label {
  display: block;
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 6px;
}
.form-row input[type="number"],
.form-row input[type="date"],
.form-row input[type="text"],
.form-row select {
  width: 100%;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 16px;
  color: var(--text);
  background: #fff;
  outline: none;
  transition: border-color 0.2s;
}
.form-row input:focus,
.form-row select:focus { border-color: var(--primary); }

.form-grid-2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0 16px;
}

/* Segmented radio buttons */
.seg {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}
.seg label { cursor: pointer; }
.seg input { display: none; }
.seg span {
  display: inline-block;
  padding: 8px 16px;
  border: 1px solid var(--border);
  border-radius: 999px;
  font-size: 14px;
  color: var(--text);
  transition: all 0.15s;
}
.seg input:checked + span {
  background: var(--primary);
  border-color: var(--primary);
  color: #fff;
}

/* Buttons */
.btn {
  display: inline-block;
  padding: 11px 28px;
  border: none;
  border-radius: 8px;
  background: var(--primary);
  color: #fff;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.2s;
}
.btn:hover { background: var(--primary-dark); }
.btn-secondary {
  background: var(--bg);
  color: var(--text);
  border: 1px solid var(--border);
}
.btn-secondary:hover { background: var(--border); background: #e8edf5; }
.btn-full { width: 100%; }

/* Result box */
.result-box {
  margin-top: 20px;
  background: var(--primary-light);
  border-radius: 10px;
  padding: 18px 20px;
  display: none;
}
.result-box.show { display: block; }
.result-box .error { color: var(--danger); font-weight: 600; }
.result-item {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  padding: 6px 0;
  font-size: 15px;
}
.result-item .val { font-weight: 700; color: var(--primary-dark); font-size: 18px; }
.result-item.highlight .val { font-size: 22px; color: var(--primary); }
.result-note { font-size: 13px; color: var(--muted); margin-top: 8px; }

.result-table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 6px;
  font-size: 15px;
}
.result-table th, .result-table td {
  border-bottom: 1px solid var(--border);
  padding: 9px 8px;
  text-align: left;
}
.result-table th { color: var(--muted); font-weight: 600; font-size: 14px; }
.result-table td:last-child, .result-table th:last-child { text-align: right; }

/* ---------- Content sections (description/how-to/FAQ) ---------- */
.content-section {
  background: var(--card);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 24px;
  margin-bottom: 24px;
}
.content-section h2 {
  font-size: 20px;
  margin-bottom: 14px;
  padding-left: 12px;
  border-left: 4px solid var(--primary);
}
.content-section p { margin-bottom: 10px; color: #374151; }
.content-section ul, .content-section ol { padding-left: 24px; color: #374151; }
.content-section li { margin-bottom: 6px; }
.content-section strong { color: var(--text); }

/* FAQ */
.faq details {
  border-bottom: 1px solid var(--border);
  padding: 12px 0;
}
.faq details:last-child { border-bottom: none; }
.faq summary {
  cursor: pointer;
  font-weight: 600;
  font-size: 15px;
  color: var(--text);
  list-style: none;
  position: relative;
  padding-right: 24px;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after {
  content: "+";
  position: absolute;
  right: 4px;
  top: 0;
  color: var(--primary);
  font-size: 18px;
  font-weight: 400;
}
.faq details[open] summary::after { content: "−"; }
.faq details p { margin-top: 8px; font-size: 14.5px; color: #4b5563; }

/* Related tools */
.related-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 12px;
}
.related-grid a {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 12px 16px;
  font-size: 14px;
  color: var(--text);
  display: flex;
  align-items: center;
  gap: 8px;
}
.related-grid a:hover {
  border-color: var(--primary);
  color: var(--primary);
  text-decoration: none;
}

/* ---------- Footer ---------- */
.site-footer {
  background: #111827;
  color: #9ca3af;
  margin-top: 40px;
  padding: 36px 0 24px;
  font-size: 14px;
}
.footer-cols {
  display: flex;
  flex-wrap: wrap;
  gap: 32px;
  justify-content: space-between;
  margin-bottom: 24px;
}
.footer-col h4 { color: #fff; font-size: 15px; margin-bottom: 10px; }
.footer-col ul { list-style: none; }
.footer-col li { margin-bottom: 6px; }
.footer-col a { color: #9ca3af; }
.footer-col a:hover { color: #fff; }
.footer-brand { max-width: 320px; }
.footer-brand .logo { color: #fff; margin-bottom: 8px; display: inline-flex; }
.copyright {
  border-top: 1px solid #1f2937;
  padding-top: 16px;
  text-align: center;
  font-size: 13px;
}

/* ---------- Responsive ---------- */
@media (max-width: 768px) {
  .nav-toggle { display: flex; }
  .site-nav {
    display: none;
    position: absolute;
    top: 60px;
    left: 0;
    right: 0;
    background: var(--card);
    box-shadow: 0 8px 16px rgba(15, 23, 42, 0.12);
    padding: 8px 16px 16px;
  }
  .site-nav.open { display: block; }
  .site-nav ul { flex-direction: column; gap: 2px; }
  .site-nav a { padding: 12px 14px; }

  .hero { padding: 40px 0 36px; }
  .hero h1 { font-size: 26px; }
  .hero p { font-size: 15px; }

  .tool-grid { grid-template-columns: repeat(auto-fill, minmax(160px, 1fr)); gap: 12px; }
  .tool-card { padding: 16px 14px; }

  .form-grid-2 { grid-template-columns: 1fr; gap: 0; }
  .tool-card-box, .content-section { padding: 18px 16px; }
  .page-title { font-size: 22px; }
  .result-item.highlight .val { font-size: 19px; }

  .footer-cols { flex-direction: column; gap: 24px; }
}