:root {
  --primary: #1d4ed8;
  --primary-dark: #1e40af;
  --primary-light: #dbeafe;
  --bg: #f8fafc;
  --text: #1e293b;
  --text-muted: #64748b;
  --border: #e2e8f0;
  --white: #ffffff;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  font-size: 16px;
  line-height: 1.6;
}

/* Header */
header {
  background: var(--white);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 1px 3px rgba(0,0,0,0.08);
}

.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.logo {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--primary);
  text-decoration: none;
}
.logo-link {
  display: flex;
  align-items: center;
  gap: 8px;
  text-decoration: none;
}

nav { display: flex; gap: 4px; flex-wrap: wrap; }

nav a {
  color: var(--text);
  text-decoration: none;
  padding: 6px 12px;
  border-radius: 6px;
  font-size: 0.9rem;
  font-weight: 500;
  transition: background 0.2s, color 0.2s;
}

nav a:hover { background: var(--primary-light); color: var(--primary); }

.hamburger { display: none; flex-direction: column; gap: 5px; cursor: pointer; }
.hamburger span { display: block; width: 24px; height: 2px; background: var(--text); border-radius: 2px; }

/* Main */
main { max-width: 1200px; margin: 0 auto; padding: 0 20px 60px; }

/* Hero */
.hero {
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
  color: var(--white);
  padding: 60px 20px;
  text-align: center;
  margin: 0 -20px 40px;
}

.hero h1 { font-size: clamp(1.8rem, 4vw, 2.8rem); margin-bottom: 16px; }
.hero p { font-size: 1.1rem; opacity: 0.9; margin-bottom: 24px; max-width: 600px; margin-left: auto; margin-right: auto; }

.search-box {
  max-width: 500px;
  margin: 0 auto;
  display: flex;
  gap: 8px;
}

.search-box input {
  flex: 1;
  padding: 12px 16px;
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  outline: none;
}

.search-box button {
  background: var(--white);
  color: var(--primary);
  border: none;
  padding: 12px 20px;
  border-radius: 8px;
  font-weight: 600;
  cursor: pointer;
}

/* Section */
section { margin-bottom: 48px; }
section h2 { font-size: 1.5rem; margin-bottom: 20px; color: var(--text); }

/* Category cards */
.category-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 16px;
}

.category-card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 24px 20px;
  text-align: center;
  text-decoration: none;
  color: var(--text);
  transition: box-shadow 0.2s, border-color 0.2s;
}

.category-card:hover { box-shadow: 0 4px 12px rgba(29,78,216,0.12); border-color: var(--primary); }
.category-card .icon { font-size: 2rem; margin-bottom: 10px; }
.category-card h3 { font-size: 1rem; font-weight: 600; margin-bottom: 4px; }
.category-card p { font-size: 0.85rem; color: var(--text-muted); }

/* Tool grid */
.tool-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 16px;
}

.tool-card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 20px;
  text-decoration: none;
  color: var(--text);
  display: block;
  transition: box-shadow 0.2s, border-color 0.2s;
}

.tool-card:hover { box-shadow: 0 4px 12px rgba(29,78,216,0.10); border-color: var(--primary); }
.tool-card h3 { font-size: 0.95rem; font-weight: 600; margin-bottom: 6px; color: var(--primary); }
.tool-card p { font-size: 0.85rem; color: var(--text-muted); line-height: 1.5; }

/* Ad placeholder */
.ad-placeholder {
  border: 2px dashed #cbd5e1;
  padding: 20px;
  text-align: center;
  color: #94a3b8;
  font-size: 12px;
  letter-spacing: 2px;
  background: #f8fafc;
  margin: 20px 0;
  border-radius: 8px;
}
.ad-placeholder::before { content: 'ADVERTISEMENT'; }

/* FAQ */
.faq-list { display: flex; flex-direction: column; gap: 12px; }

.faq-item {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: 10px;
  overflow: hidden;
}

.faq-q {
  padding: 16px 20px;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  user-select: none;
}

.faq-q:hover { background: var(--primary-light); }
.faq-q .arrow { transition: transform 0.2s; }
.faq-item.open .faq-q .arrow { transform: rotate(180deg); }

.faq-a {
  padding: 0 20px;
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease, padding 0.3s;
  color: var(--text-muted);
}

.faq-item.open .faq-a { max-height: 300px; padding: 0 20px 16px; }

/* Tool page */
.breadcrumb { display:flex; align-items:center; flex-wrap:wrap; gap:4px; padding:16px 20px; font-size:13px; background:#f8fafc; border-bottom:1px solid #e2e8f0; }
.breadcrumb a { color:#1d4ed8; text-decoration:none; white-space:nowrap; }
.breadcrumb a:hover { text-decoration:underline; }
.breadcrumb .separator { color:#cbd5e1; }
.breadcrumb .current { color:#64748b; white-space:nowrap; }

.tool-page h1 { font-size: clamp(1.4rem, 3vw, 2rem); margin-bottom: 24px; }

.calculator-box {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 28px;
  margin-bottom: 24px;
}

.form-group { margin-bottom: 16px; }
.form-group label { display: block; font-weight: 500; margin-bottom: 6px; font-size: 0.9rem; }

.form-group input,
.form-group select {
  width: 100%;
  padding: 10px 14px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 1rem;
  outline: none;
  transition: border-color 0.2s;
  background: var(--white);
}

.form-group input:focus,
.form-group select:focus { border-color: var(--primary); box-shadow: 0 0 0 3px rgba(29,78,216,0.1); }

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

.result-box {
  background: var(--primary-light);
  border: 1px solid var(--primary);
  border-radius: 10px;
  padding: 20px;
  margin-top: 20px;
}

.result-box h3 { color: var(--primary-dark); margin-bottom: 12px; font-size: 1rem; }

.result-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 8px 0;
  border-bottom: 1px solid rgba(29,78,216,0.15);
}
.result-item:last-child { border-bottom: none; }
.result-label { font-size: 0.9rem; color: var(--text-muted); }
.result-value { font-size: 1.1rem; font-weight: 700; color: var(--primary-dark); }
.result-highlight { font-size: 1.3rem; }

.btn-calc {
  background: var(--primary);
  color: var(--white);
  border: none;
  padding: 12px 28px;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  width: 100%;
  margin-top: 8px;
  transition: background 0.2s;
}
.btn-calc:hover { background: var(--primary-dark); }

.info-box {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 24px;
  margin-bottom: 24px;
  line-height: 1.8;
  color: var(--text-muted);
}

.related-tools {
  background: #eff6ff;
  border-radius: 10px;
  padding: 24px 28px;
  margin: 40px 0;
}
.related-tools h3 {
  font-size: 18px;
  font-weight: 700;
  color: #1e293b;
  margin-bottom: 16px;
}
.related-tools ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}
.related-tools ul li {
  display: flex;
  align-items: flex-start;
  gap: 8px;
  font-size: 14px;
}
.related-tools ul li::before {
  content: "→";
  color: #1d4ed8;
  font-weight: 700;
  flex-shrink: 0;
  margin-top: 1px;
}
.related-tools ul li a {
  color: #1d4ed8;
  text-decoration: none;
}
.related-tools ul li a:hover { text-decoration: underline; }
@media (max-width: 600px) {
  .related-tools ul { grid-template-columns: 1fr; }
}

.disclaimer {
  background: #fffbeb;
  border: 1px solid #fcd34d;
  border-radius: 8px;
  padding: 16px 20px;
  margin: 32px 0;
  font-size: 13px;
  color: #78716c;
  line-height: 1.7;
}
.disclaimer strong { color: #92400e; }

/* Footer */
footer {
  background: var(--text);
  color: #94a3b8;
  padding: 40px 20px;
  margin-top: 60px;
}

.footer-inner { max-width: 1200px; margin: 0 auto; text-align: center; }
.footer-inner p { margin-bottom: 10px; font-size: 0.9rem; }
.footer-links { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; margin-bottom: 16px; }
.footer-links a { color: #94a3b8; text-decoration: none; font-size: 0.9rem; }
.footer-links a:hover { color: var(--white); }

/* Responsive */
@media (max-width: 768px) {
  nav { display: none; }
  nav.open { display: flex; flex-direction: column; position: absolute; top: 64px; left: 0; right: 0; background: var(--white); border-bottom: 1px solid var(--border); padding: 12px; }
  .hamburger { display: flex; }
  .form-row { grid-template-columns: 1fr; }
  .header-inner { position: relative; }
  .hero { padding: 40px 20px; }
}

/* Alert box */
.alert { padding: 12px 16px; border-radius: 8px; margin: 12px 0; font-size: 0.9rem; }
.alert-success { background: #dcfce7; color: #166534; border: 1px solid #86efac; }
.alert-warning { background: #fef3c7; color: #92400e; border: 1px solid #fcd34d; }
.alert-info { background: var(--primary-light); color: var(--primary-dark); border: 1px solid #93c5fd; }

/* ===== Tool page content sections ===== */
.description {
  background: #f8fafc;
  border-left: 4px solid #1d4ed8;
  border-radius: 0 8px 8px 0;
  padding: 24px 28px;
  margin: 40px 0;
}
.description h2 {
  font-size: 20px;
  font-weight: 700;
  color: #1e293b;
  margin-bottom: 12px;
}
.description p {
  font-size: 15px;
  color: #475569;
  line-height: 1.8;
}

/* FAQ with native <details>/<summary> */
.faq {
  margin: 40px 0;
}
.faq > h2 {
  font-size: 22px;
  font-weight: 700;
  color: #1e293b;
  margin-bottom: 20px;
  padding-bottom: 10px;
  border-bottom: 2px solid #e2e8f0;
}
.faq details {
  border: 1px solid #e2e8f0;
  border-radius: 8px;
  margin-bottom: 10px;
  overflow: hidden;
}
.faq details summary {
  padding: 16px 20px;
  font-size: 15px;
  font-weight: 600;
  color: #1e293b;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: #fff;
  list-style: none;
  user-select: none;
}
.faq details summary::-webkit-details-marker { display: none; }
.faq details summary::after {
  content: "▾";
  color: #1d4ed8;
  font-size: 18px;
  transition: transform 0.2s;
  flex-shrink: 0;
}
.faq details[open] summary::after { transform: rotate(180deg); }
.faq details summary:hover { background: #f8fafc; }
.faq details p {
  padding: 16px 20px;
  font-size: 14px;
  color: #475569;
  line-height: 1.8;
  border-top: 1px solid #e2e8f0;
  background: #fafafa;
  margin: 0;
}

/* ===== All Tools Tab + Pagination ===== */
.all-tools-section h2 { font-size: 1.5rem; margin-bottom: 20px; }

.category-tabs {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 24px;
}
.tab-btn {
  padding: 8px 16px;
  border: 1px solid var(--border);
  border-radius: 20px;
  background: var(--white);
  color: var(--text);
  font-size: 0.85rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s;
}
.tab-btn:hover { border-color: var(--primary); color: var(--primary); }
.tab-btn.active { background: var(--primary); color: var(--white); border-color: var(--primary); }

.tools-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 14px;
  min-height: 200px;
}

.pagination {
  display: flex;
  justify-content: center;
  gap: 8px;
  margin-top: 28px;
  flex-wrap: wrap;
}
.page-btn {
  width: 38px;
  height: 38px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--white);
  color: var(--text);
  font-size: 0.9rem;
  cursor: pointer;
  transition: all 0.2s;
  display: flex;
  align-items: center;
  justify-content: center;
}
.page-btn:hover { border-color: var(--primary); color: var(--primary); }
.page-btn.active { background: var(--primary); color: var(--white); border-color: var(--primary); }
.page-btn.prev-next { width: auto; padding: 0 14px; font-size: 0.85rem; }