:root {
  --color-bg: #f6f7f9;
  --color-surface: #ffffff;
  --color-ink: #1e293b;
  --color-muted: #5b6b7f;
  --color-primary: #1e3a5f;
  --color-primary-soft: #eef3f8;
  --color-accent: #f97316;
  --color-accent-soft: #fff3e8;
  --color-border: #e2e8f0;
  --color-success-bg: #f0fdf4;
  --color-success-border: #86efac;
  --radius: 12px;
  --shadow: 0 1px 3px rgba(15, 23, 42, 0.08), 0 4px 16px rgba(15, 23, 42, 0.05);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background: var(--color-bg);
  color: var(--color-ink);
  line-height: 1.6;
}

a {
  color: var(--color-primary);
  text-underline-offset: 3px;
}

a:hover {
  color: var(--color-accent);
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
}

.header-inner {
  max-width: 1024px;
  margin: 0 auto;
  padding: 0.7rem 1rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-size: 1.15rem;
  font-weight: 800;
  color: var(--color-primary);
  text-decoration: none;
}

.brand-mark {
  width: 34px;
  height: 34px;
  border-radius: 9px;
  background: linear-gradient(135deg, var(--color-accent), #fb923c);
  color: #fff;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  font-weight: 900;
}

.site-nav {
  display: flex;
  gap: 1.1rem;
  font-size: 0.95rem;
  font-weight: 600;
}

.site-nav a {
  color: var(--color-muted);
  text-decoration: none;
}

.site-nav a:hover,
.site-nav a[aria-current="page"] {
  color: var(--color-primary);
}

/* Layout */
.container {
  max-width: 1024px;
  margin: 0 auto;
  padding: 1.4rem 1rem 3rem;
}

.breadcrumb {
  font-size: 0.88rem;
  color: var(--color-muted);
  margin: 0 0 1rem;
}

.breadcrumb a {
  color: var(--color-muted);
  text-decoration: none;
}

.breadcrumb a:hover {
  color: var(--color-accent);
}

.hero h1 {
  font-size: clamp(1.7rem, 4vw, 2.4rem);
  line-height: 1.2;
  margin: 0 0 0.5rem;
  color: var(--color-primary);
}

.lead {
  font-size: 1.08rem;
  color: var(--color-muted);
  max-width: 70ch;
  margin: 0 0 1.4rem;
}

/* Cards */
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1.2rem;
}

/* Tool layout */
.tool-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.2rem;
}

@media (min-width: 860px) {
  .tool-grid {
    grid-template-columns: 1.15fr 0.85fr;
    align-items: start;
  }
}

.tool-inputs h2,
.tool-results h2 {
  font-size: 1.1rem;
  margin: 0 0 0.9rem;
  color: var(--color-primary);
}

.field {
  margin-bottom: 0.85rem;
}

.field label {
  display: block;
  font-size: 0.92rem;
  font-weight: 600;
  margin-bottom: 0.3rem;
}

.field .hint {
  display: block;
  font-size: 0.78rem;
  color: var(--color-muted);
  font-weight: 400;
  margin-top: 0.15rem;
}

.field input,
.field select {
  width: 100%;
  padding: 0.6rem 0.75rem;
  border: 1px solid var(--color-border);
  border-radius: 9px;
  font-size: 1rem;
  color: var(--color-ink);
  background: #fbfcfe;
  transition: border-color 0.15s, box-shadow 0.15s;
}

.field input:focus,
.field select:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px rgba(249, 115, 22, 0.18);
  background: #fff;
}

.field-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.8rem;
}

.tool-results {
  background: var(--color-primary-soft);
  border: 1px solid #d6e1ec;
  border-radius: var(--radius);
  padding: 1.1rem;
}

.result-item {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 0.8rem;
  padding: 0.55rem 0;
  border-bottom: 1px dashed #cbd8e6;
}

.result-item:last-child {
  border-bottom: none;
}

.result-label {
  font-size: 0.9rem;
  color: var(--color-muted);
}

.result-value {
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--color-primary);
  text-align: right;
  white-space: nowrap;
}

.result-note {
  font-size: 0.82rem;
  color: var(--color-muted);
  margin: 0.7rem 0 0;
}

/* Content */
.prose {
  max-width: 72ch;
  margin-top: 2rem;
}

.prose h2 {
  font-size: 1.35rem;
  color: var(--color-primary);
  margin: 1.8rem 0 0.6rem;
}

.prose h3 {
  font-size: 1.05rem;
  color: var(--color-primary);
  margin: 1.3rem 0 0.4rem;
}

.prose p,
.prose li {
  color: #334155;
}

.prose ul,
.prose ol {
  padding-left: 1.3rem;
}

.prose table {
  border-collapse: collapse;
  width: 100%;
  margin: 1rem 0;
  font-size: 0.95rem;
}

.prose th,
.prose td {
  border: 1px solid var(--color-border);
  padding: 0.55rem 0.7rem;
  text-align: left;
}

.prose th {
  background: var(--color-primary-soft);
  color: var(--color-primary);
}

.callout {
  background: var(--color-accent-soft);
  border-left: 4px solid var(--color-accent);
  border-radius: 0 9px 9px 0;
  padding: 0.85rem 1rem;
  font-size: 0.95rem;
  margin: 1.2rem 0;
}

/* FAQ */
.faq {
  margin-top: 2rem;
}

.faq h2 {
  font-size: 1.35rem;
  color: var(--color-primary);
}

.faq details {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 10px;
  margin-bottom: 0.7rem;
  padding: 0.85rem 1rem;
}

.faq summary {
  cursor: pointer;
  font-weight: 600;
  color: var(--color-primary);
}

.faq details p {
  margin: 0.6rem 0 0;
  color: #334155;
}

/* Related tools */
.related {
  margin-top: 2.2rem;
}

.related h2 {
  font-size: 1.2rem;
  color: var(--color-primary);
}

.related-links {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(210px, 1fr));
  gap: 0.7rem;
  padding: 0;
  list-style: none;
}

.related-links a {
  display: block;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 9px;
  padding: 0.6rem 0.8rem;
  text-decoration: none;
  font-weight: 600;
  font-size: 0.92rem;
  color: var(--color-primary);
}

.related-links a:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
}

/* Home tool grid */
.tool-grid-home {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  gap: 1rem;
  margin-top: 1.4rem;
}

.tool-card-home {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1.1rem;
  text-decoration: none;
  color: var(--color-ink);
  transition: transform 0.12s, border-color 0.12s;
}

.tool-card-home:hover {
  transform: translateY(-2px);
  border-color: var(--color-accent);
}

.tool-card-home .tool-icon {
  font-size: 1.6rem;
}

.tool-card-home h2 {
  font-size: 1.05rem;
  margin: 0.5rem 0 0.3rem;
  color: var(--color-primary);
}

.tool-card-home p {
  margin: 0;
  font-size: 0.9rem;
  color: var(--color-muted);
}

/* Generic pages */
.page-section {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1.4rem;
  max-width: 72ch;
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--color-border);
  background: var(--color-surface);
  padding: 1.4rem 1rem 2rem;
  font-size: 0.88rem;
  color: var(--color-muted);
}

.footer-inner {
  max-width: 1024px;
  margin: 0 auto;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 0.8rem;
}

.footer-links {
  display: flex;
  gap: 1rem;
}

.footer-links a {
  color: var(--color-muted);
  text-decoration: none;
}

.footer-links a:hover {
  color: var(--color-accent);
}

/* 404 */
.not-found {
  text-align: center;
  padding: 4rem 1rem;
}

.not-found h1 {
  font-size: 2.2rem;
  color: var(--color-primary);
}

@media (max-width: 640px) {
  .site-nav {
    gap: 0.8rem;
    font-size: 0.88rem;
  }

  .field-row {
    grid-template-columns: 1fr;
  }

  .result-value {
    font-size: 1.1rem;
  }
}