:root {
  --color-bg: #ffffff;
  --color-text: #1a1a2e;
  --color-muted: #64748b;
  --color-primary: #2563eb;
  --color-primary-hover: #1d4ed8;
  --color-border: #e2e8f0;
  --color-card-bg: #f8fafc;
  --color-accent: #10b981;
  --radius: 8px;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.container {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 1.5rem;
  width: 100%;
}

/* Header */
.site-header {
  border-bottom: 1px solid var(--color-border);
  padding: 1.5rem 0;
  margin-bottom: 2rem;
}

.site-title {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-text);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.site-logo {
  width: 28px;
  height: 28px;
  flex-shrink: 0;
}

.site-tagline {
  color: var(--color-muted);
  font-size: 0.95rem;
  margin-top: 0.25rem;
}

/* Breadcrumb */
.breadcrumb {
  font-size: 0.875rem;
  color: var(--color-muted);
  margin-bottom: 1.5rem;
}

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

/* Search */
.search-box {
  margin-bottom: 2rem;
}

.search-box input {
  width: 100%;
  padding: 0.75rem 1rem;
  font-size: 1.05rem;
  border: 2px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-bg);
  color: var(--color-text);
  transition: border-color 0.2s, box-shadow 0.2s;
}

.search-box input:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
}

.search-box input::placeholder {
  color: var(--color-muted);
}

/* Tool cards on home page */
.tools-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 1.25rem;
  margin-top: 1.5rem;
}

.tool-card {
  background: var(--color-card-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.5rem;
  text-decoration: none;
  color: inherit;
  transition: box-shadow 0.2s, border-color 0.2s;
}

.tool-card:hover {
  border-color: var(--color-primary);
  box-shadow: 0 2px 12px rgba(37, 99, 235, 0.1);
}

.tool-card h2 {
  font-size: 1.1rem;
  margin-bottom: 0.5rem;
}

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

/* Tool page styles */
.tool-header {
  margin-bottom: 2rem;
}

.tool-header h1 {
  font-size: 1.75rem;
  margin-bottom: 0.5rem;
}

.tool-header p {
  color: var(--color-muted);
}

/* Forms */
.calc-form {
  background: var(--color-card-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin-bottom: 1.5rem;
}

.form-group {
  margin-bottom: 1.25rem;
}

.form-group label {
  display: block;
  font-weight: 600;
  font-size: 0.9rem;
  margin-bottom: 0.35rem;
}

.form-group .hint {
  font-size: 0.8rem;
  color: var(--color-muted);
  margin-bottom: 0.35rem;
}

.form-group input,
.form-group select {
  width: 100%;
  padding: 0.6rem 0.75rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  font-size: 1rem;
  background: var(--color-bg);
  color: var(--color-text);
}

.form-group input:focus,
.form-group select:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
}

.btn {
  display: inline-block;
  padding: 0.65rem 1.5rem;
  background: var(--color-primary);
  color: #fff;
  border: none;
  border-radius: var(--radius);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.2s;
}

.btn:hover {
  background: var(--color-primary-hover);
}

/* Results */
.results {
  display: none;
  background: var(--color-card-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin-bottom: 1.5rem;
}

.results.visible {
  display: block;
}

.results h2 {
  font-size: 1.2rem;
  margin-bottom: 1rem;
}

.result-row {
  display: flex;
  justify-content: space-between;
  padding: 0.6rem 0;
  border-bottom: 1px solid var(--color-border);
}

.result-row:last-child {
  border-bottom: none;
  font-weight: 700;
  color: var(--color-primary);
}

.result-label {
  color: var(--color-muted);
}

.result-value {
  font-weight: 600;
}

/* Amortization table */
.amortization-section {
  display: none;
  margin-top: 1.5rem;
}

.amortization-section.visible {
  display: block;
}

.amortization-section h2 {
  font-size: 1.2rem;
  margin-bottom: 1rem;
}

.table-wrap {
  overflow-x: auto;
}

.amortization-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.875rem;
}

.amortization-table th,
.amortization-table td {
  padding: 0.5rem 0.75rem;
  text-align: right;
  border-bottom: 1px solid var(--color-border);
}

.amortization-table th {
  font-weight: 600;
  color: var(--color-muted);
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.03em;
}

.amortization-table td:first-child,
.amortization-table th:first-child {
  text-align: left;
}

/* Blog post styles */
.post-header {
  margin-bottom: 2rem;
}

.post-header h1 {
  font-size: 1.75rem;
  line-height: 1.3;
  margin-bottom: 0.75rem;
}

.post-meta {
  display: flex;
  gap: 1rem;
  color: var(--color-muted);
  font-size: 0.875rem;
  flex-wrap: wrap;
}

.post-category {
  background: var(--color-card-bg);
  border: 1px solid var(--color-border);
  border-radius: 4px;
  padding: 0.1rem 0.5rem;
  font-size: 0.8rem;
}

.post-content {
  line-height: 1.8;
}

.post-content h2 {
  font-size: 1.35rem;
  margin-top: 2rem;
  margin-bottom: 0.75rem;
}

.post-content h3 {
  font-size: 1.1rem;
  margin-top: 1.5rem;
  margin-bottom: 0.5rem;
}

.post-content p {
  margin-bottom: 1rem;
}

.post-content ul,
.post-content ol {
  margin-bottom: 1rem;
  padding-left: 1.5rem;
}

.post-content li {
  margin-bottom: 0.35rem;
}

.post-content code {
  background: var(--color-card-bg);
  border: 1px solid var(--color-border);
  border-radius: 3px;
  padding: 0.15rem 0.4rem;
  font-size: 0.9em;
  font-family: monospace;
}

.post-content pre {
  background: var(--color-card-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1rem;
  overflow-x: auto;
  margin-bottom: 1rem;
}

.post-content pre code {
  border: none;
  padding: 0;
  background: none;
}

.post-content blockquote {
  border-left: 3px solid var(--color-primary);
  padding-left: 1rem;
  margin: 1rem 0;
  color: var(--color-muted);
  font-style: italic;
}

.post-content table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 1rem;
  font-size: 0.9rem;
}

.post-content th,
.post-content td {
  padding: 0.5rem 0.75rem;
  border: 1px solid var(--color-border);
  text-align: left;
}

.post-content th {
  background: var(--color-card-bg);
  font-weight: 600;
}

.post-content strong {
  font-weight: 700;
}

.related-tool-box {
  background: var(--color-card-bg);
  border: 1px solid var(--color-primary);
  border-radius: var(--radius);
  padding: 1rem 1.25rem;
  margin-top: 2rem;
}

.related-tool-box a {
  color: var(--color-primary);
  font-weight: 600;
  text-decoration: none;
}

.related-tool-box a:hover {
  text-decoration: underline;
}

/* Blog index */
.blog-list {
  list-style: none;
  padding: 0;
}

.blog-list li {
  border-bottom: 1px solid var(--color-border);
  padding: 1.25rem 0;
}

.blog-list li:last-child {
  border-bottom: none;
}

.blog-list a {
  text-decoration: none;
  color: inherit;
}

.blog-list h3 {
  font-size: 1.1rem;
  margin-bottom: 0.25rem;
  color: var(--color-text);
}

.blog-list a:hover h3 {
  color: var(--color-primary);
}

.blog-list .blog-excerpt {
  color: var(--color-muted);
  font-size: 0.9rem;
}

.blog-list .blog-meta {
  color: var(--color-muted);
  font-size: 0.8rem;
  margin-bottom: 0.25rem;
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--color-border);
  padding: 2rem 0 1.5rem;
  margin-top: 3rem;
  color: var(--color-muted);
  font-size: 0.85rem;
}

.footer-tools {
  margin-bottom: 1.5rem;
}

.footer-tools h3 {
  font-size: 0.9rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text);
  margin-bottom: 0.75rem;
}

.footer-tools-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem 1rem;
}

.footer-tools-grid a {
  color: var(--color-muted);
  text-decoration: none;
  font-size: 0.8rem;
  transition: color 0.15s;
}

.footer-tools-grid a:hover {
  color: var(--color-primary);
}

.footer-credit {
  padding-top: 1rem;
  border-top: 1px solid var(--color-border);
}

main {
  flex: 1;
}

.blog-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.25rem;
  margin-top: 1.5rem;
}

@media (max-width: 600px) {
  .tools-grid,
  .blog-grid {
    grid-template-columns: 1fr;
  }
}