/* Shared styles for SEO static pages: landing, features, solutions */
:root {
  --sf-font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --sf-text: #1e293b;
  --sf-text-muted: #64748b;
  --sf-bg: #ffffff;
  --sf-bg-alt: #f8fafc;
  --sf-accent: #6366f1;
  --sf-accent-hover: #4f46e5;
  --sf-border: #e2e8f0;
  --sf-card-bg: #ffffff;
  --sf-radius: 12px;
  --sf-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: var(--sf-font);
  font-size: 16px;
  line-height: 1.6;
  color: var(--sf-text);
  background: var(--sf-bg);
}

.sf-container {
  max-width: 960px;
  margin: 0 auto;
  padding: 0 1.25rem;
}

.sf-nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 0;
  border-bottom: 1px solid var(--sf-border);
  flex-wrap: wrap;
  gap: 0.75rem;
}

.sf-nav-links {
  display: flex;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
}

.sf-nav-links a {
  color: var(--sf-text-muted);
  text-decoration: none;
  font-weight: 500;
}

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

.sf-lang-select {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.sf-lang-select label {
  font-size: 0.875rem;
  color: var(--sf-text-muted);
}

.sf-lang-select select {
  padding: 0.375rem 0.75rem;
  border: 1px solid var(--sf-border);
  border-radius: 8px;
  font-family: inherit;
  font-size: 0.875rem;
  background: var(--sf-bg);
  color: var(--sf-text);
  cursor: pointer;
}

.sf-hero {
  padding: 3rem 0;
  text-align: center;
}

.sf-hero h1 {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 700;
  line-height: 1.2;
  margin: 0 0 1rem;
}

.sf-hero .sf-subheadline {
  font-size: 1.125rem;
  color: var(--sf-text-muted);
  max-width: 640px;
  margin: 0 auto 1.5rem;
}

.sf-cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  justify-content: center;
  margin-top: 1.5rem;
}

.sf-btn {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  font-family: inherit;
  font-size: 1rem;
  font-weight: 600;
  text-decoration: none;
  border-radius: 8px;
  cursor: pointer;
  transition: background 0.2s, color 0.2s;
  border: none;
}

.sf-btn-primary {
  background: var(--sf-accent);
  color: white;
}

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

.sf-btn-secondary {
  background: var(--sf-bg-alt);
  color: var(--sf-text);
  border: 1px solid var(--sf-border);
}

.sf-btn-secondary:hover {
  background: var(--sf-border);
  color: var(--sf-text);
}

.sf-section {
  padding: 2.5rem 0;
}

.sf-section:nth-child(even) {
  background: var(--sf-bg-alt);
}

.sf-section h2 {
  font-size: 1.5rem;
  font-weight: 700;
  margin: 0 0 1.25rem;
  text-align: center;
}

.sf-cards {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.25rem;
  margin-top: 1.5rem;
}

.sf-card {
  background: var(--sf-card-bg);
  border: 1px solid var(--sf-border);
  border-radius: var(--sf-radius);
  padding: 1.25rem;
  box-shadow: var(--sf-shadow);
}

.sf-card h3 {
  font-size: 1.125rem;
  font-weight: 600;
  margin: 0 0 0.5rem;
}

.sf-card p,
.sf-card ul {
  margin: 0;
  font-size: 0.9375rem;
  color: var(--sf-text-muted);
}

.sf-card ul {
  padding-left: 1.25rem;
}

.sf-card li {
  margin-bottom: 0.25rem;
}

/* Feature highlight cards with accent */
.sf-card-feature {
  border-left: 4px solid var(--sf-accent);
  padding-left: 1.5rem;
  transition: box-shadow 0.2s ease;
}

.sf-card-feature:hover {
  box-shadow: 0 8px 24px -4px rgba(99, 102, 241, 0.12), 0 4px 8px -2px rgba(0, 0, 0, 0.06);
}

.sf-card-feature h3 {
  color: var(--sf-text);
  font-size: 1.2rem;
}

/* Tab-style method switcher (compact, one visible at a time) */
.sf-method-tabs {
  margin-top: 1.5rem;
  max-width: 560px;
  margin-left: auto;
  margin-right: auto;
}

.sf-method-tabs-nav {
  display: flex;
  gap: 0.25rem;
  border-bottom: 2px solid var(--sf-border);
  margin-bottom: 0;
}

.sf-method-tabs-nav a {
  padding: 0.75rem 1.25rem;
  font-weight: 600;
  font-size: 0.9375rem;
  color: var(--sf-text-muted);
  text-decoration: none;
  border-bottom: 2px solid transparent;
  margin-bottom: -2px;
  transition: color 0.2s, border-color 0.2s;
}

.sf-method-tabs-nav a:hover {
  color: var(--sf-accent);
}

.sf-method-tabs-nav a.sf-tab-active {
  color: var(--sf-accent);
  border-bottom-color: var(--sf-accent);
}

.sf-method-tab-panel {
  display: none;
  padding: 1.25rem 0 0;
}

.sf-method-tab-panel.sf-tab-active {
  display: block;
}

.sf-method-tab-panel h3 {
  font-size: 1.125rem;
  font-weight: 600;
  margin: 0 0 0.5rem;
  color: var(--sf-text);
}

.sf-method-tab-panel p {
  margin: 0 0 0.75rem;
  font-size: 0.9375rem;
  color: var(--sf-text-muted);
}

.sf-method-tab-panel ul {
  margin: 0;
  padding-left: 1.25rem;
  font-size: 0.9375rem;
  color: var(--sf-text-muted);
}

.sf-method-tab-panel li {
  margin-bottom: 0.25rem;
}

/* FAQ accordion with + / − toggle */
.sf-faq-accordion {
  max-width: 640px;
  margin: 1.5rem auto 0;
}

.sf-faq-item {
  border: 1px solid var(--sf-border);
  border-radius: var(--sf-radius);
  margin-bottom: 0.5rem;
  overflow: hidden;
  background: var(--sf-card-bg);
}

.sf-faq-item:last-child {
  margin-bottom: 0;
}

.sf-faq-item summary {
  list-style: none;
  padding: 1rem 1.25rem;
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  transition: background 0.2s;
}

.sf-faq-item summary::-webkit-details-marker,
.sf-faq-item summary::marker {
  display: none;
}

.sf-faq-item summary::after {
  content: '+';
  flex-shrink: 0;
  width: 1.5rem;
  height: 1.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  font-weight: 400;
  color: var(--sf-accent);
  line-height: 1;
}

.sf-faq-item[open] summary::after {
  content: '−';
}

.sf-faq-item summary:hover {
  background: var(--sf-bg-alt);
}

.sf-faq-item .sf-faq-content {
  padding: 0 1.25rem 1.25rem;
  border-top: 1px solid var(--sf-border);
}

.sf-faq-item .sf-faq-content p,
.sf-faq-item .sf-faq-content ul {
  margin: 0 0 0.75rem;
  font-size: 0.9375rem;
  color: var(--sf-text-muted);
  line-height: 1.6;
}

.sf-faq-item .sf-faq-content p:last-child,
.sf-faq-item .sf-faq-content ul:last-child {
  margin-bottom: 0;
}

.sf-faq-item .sf-faq-content ul {
  padding-left: 1.25rem;
}

.sf-faq-item .sf-faq-content li {
  margin-bottom: 0.25rem;
}

/* Accordion with chevron on left (Memrise-style) */
.sf-accordion-chevron {
  max-width: 720px;
  margin: 1.5rem auto 0;
  border-top: 1px solid var(--sf-border);
}

.sf-accordion-chevron .sf-accordion-item {
  border-bottom: 1px solid var(--sf-border);
}

.sf-accordion-chevron .sf-accordion-item summary {
  list-style: none;
  padding: 1rem 0;
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  transition: background 0.2s;
}

.sf-accordion-chevron .sf-accordion-item summary::-webkit-details-marker,
.sf-accordion-chevron .sf-accordion-item summary::marker {
  display: none;
}

.sf-accordion-chevron .sf-accordion-item summary::before {
  content: '›';
  flex-shrink: 0;
  font-size: 1.25rem;
  font-weight: 400;
  color: var(--sf-text-muted);
  transform: rotate(0deg);
  transition: transform 0.2s;
}

.sf-accordion-chevron .sf-accordion-item[open] summary::before {
  content: '›';
  transform: rotate(90deg);
}

.sf-accordion-chevron .sf-accordion-item summary:hover {
  color: var(--sf-accent);
}

.sf-accordion-chevron .sf-accordion-item .sf-accordion-content {
  padding: 0 0 1.25rem 1.75rem;
}

.sf-accordion-chevron .sf-accordion-item .sf-accordion-content p,
.sf-accordion-chevron .sf-accordion-item .sf-accordion-content ul {
  margin: 0 0 0.75rem;
  font-size: 0.9375rem;
  color: var(--sf-text-muted);
  line-height: 1.6;
}

.sf-accordion-chevron .sf-accordion-item .sf-accordion-content p:last-child,
.sf-accordion-chevron .sf-accordion-item .sf-accordion-content ul:last-child {
  margin-bottom: 0;
}

.sf-accordion-chevron .sf-accordion-item .sf-accordion-content ul {
  padding-left: 1.25rem;
}

.sf-accordion-chevron .sf-accordion-item .sf-accordion-content li {
  margin-bottom: 0.25rem;
}

/* Citation list: vertical stack with horizontal dividers (no cards) */
.sf-citation-list {
  max-width: 720px;
  margin: 1.5rem auto 0;
  border-top: 1px solid var(--sf-border);
}

.sf-citation-group {
  padding: 1.25rem 0;
  border-bottom: 1px solid var(--sf-border);
}

.sf-citation-group:last-child {
  border-bottom: none;
}

.sf-citation-group h3 {
  font-size: 1rem;
  font-weight: 600;
  margin: 0 0 0.75rem;
  color: var(--sf-text);
}

.sf-citation-group ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

.sf-citation-group li {
  margin-bottom: 0.5rem;
  font-size: 0.9375rem;
  color: var(--sf-text-muted);
  line-height: 1.5;
}

.sf-citation-group li:last-child {
  margin-bottom: 0;
}

.sf-citation-group a {
  color: var(--sf-accent);
  text-decoration: none;
}

.sf-citation-group a:hover {
  text-decoration: underline;
}

/* Finding list: vertical stack with horizontal dividers (no cards) */
.sf-finding-list {
  max-width: 720px;
  margin: 1.5rem auto 0;
  border-top: 1px solid var(--sf-border);
}

.sf-finding-group {
  padding: 1.25rem 0;
  border-bottom: 1px solid var(--sf-border);
}

.sf-finding-group:last-child {
  border-bottom: none;
}

.sf-finding-group h3 {
  font-size: 1rem;
  font-weight: 600;
  margin: 0 0 0.5rem;
  color: var(--sf-text);
}

.sf-finding-group p {
  margin: 0;
  font-size: 0.9375rem;
  color: var(--sf-text-muted);
  line-height: 1.6;
}

/* Callout block for important notes */
.sf-callout {
  background: linear-gradient(135deg, rgba(99, 102, 241, 0.06) 0%, rgba(99, 102, 241, 0.02) 100%);
  border-left: 4px solid var(--sf-accent);
  border-radius: var(--sf-radius);
  padding: 1.5rem 1.5rem 1.5rem 1.75rem;
  margin-top: 1.5rem;
}

.sf-callout p {
  margin: 0 0 0.75rem;
  color: var(--sf-text);
  font-size: 0.9375rem;
}

.sf-callout p:last-child {
  margin-bottom: 0;
}

.sf-callout strong {
  color: var(--sf-accent);
}

/* Section intro with better typography */
.sf-section-intro {
  max-width: 640px;
  margin: 0 auto 2rem;
  text-align: center;
  color: var(--sf-text-muted);
  font-size: 1rem;
  line-height: 1.7;
}

.sf-section-intro + .sf-cards {
  margin-top: 0;
}

.sf-steps {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1.5rem;
  margin-top: 1.5rem;
}

.sf-step {
  text-align: center;
  padding: 1rem;
}

.sf-step strong {
  display: block;
  margin-bottom: 0.5rem;
}

.sf-step span {
  font-size: 0.9375rem;
  color: var(--sf-text-muted);
}

.sf-seo-paragraph {
  font-size: 0.9375rem;
  color: var(--sf-text-muted);
  max-width: 720px;
  margin: 2rem auto;
  line-height: 1.7;
}

.sf-footer {
  padding: 2rem 0;
  border-top: 1px solid var(--sf-border);
  text-align: center;
  font-size: 0.875rem;
  color: var(--sf-text-muted);
}

.sf-footer a {
  color: var(--sf-accent);
  text-decoration: none;
}

.sf-footer a:hover {
  text-decoration: underline;
}

@media (max-width: 640px) {
  .sf-hero {
    padding: 2rem 0;
  }
  .sf-cta-row {
    flex-direction: column;
  }
  .sf-cta-row .sf-btn {
    width: 100%;
    text-align: center;
  }
}