/* ─── PrepZone SEO Website Stylesheet ─────────────────────────────── */
/* Green accent: #16A34A, dark text: #1E293B, off-white bg: #F9FAFB    */
/* Fonts: Instrument Serif (headings), DM Sans (body)                 */
/* Spacious typography with generous spacing between elements          */
/* ──────────────────────────────────────────────────────────────────── */

:root {
  --accent: #16A34A;
  --accent-hover: #15803D;
  --accent-light: #F0FDF4;
  --text: #1E293B;
  --text-muted: #64748B;
  --bg: #F9FAFB;
  --white: #FFFFFF;
  --border: #E2E8F0;
  --max-width: 960px;
  --font-heading: 'Instrument Serif', Georgia, serif;
  --font-body: 'DM Sans', -apple-system, BlinkMacSystemFont, sans-serif;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
}

body {
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.85;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}

/* ─── Container ──────────────────────────────────────────────────── */

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* ─── Banner / Header ────────────────────────────────────────────── */

.banner {
  background: var(--white);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
  padding: 8px 0;
}

.banner .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo-link {
  display: flex;
  align-items: center;
  gap: 8px;
  text-decoration: none;
  color: var(--text);
  font-weight: 700;
  font-size: 1rem;
}

.logo {
  height: 18px;
  width: auto;
  border-radius: 8px;
}

.main-nav {
  display: flex;
  gap: 24px;
}

.main-nav a {
  text-decoration: none;
  color: var(--text-muted);
  font-size: 0.82rem;
  font-weight: 500;
  transition: color 0.2s;
}

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

/* ─── Cover Section ──────────────────────────────────────────────── */

.cover-section {
  padding: 48px 0 32px;
  text-align: center;
}

.cover-badge {
  display: inline-block;
  background: var(--accent-light);
  color: var(--accent);
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 6px 18px;
  border-radius: 100px;
  margin-bottom: 24px;
}

.article-title {
  font-family: var(--font-heading);
  font-size: 2.5rem;
  font-weight: 400;
  line-height: 1.2;
  color: var(--text);
  margin-bottom: 20px;
}

.article-subtitle {
  font-size: 1rem;
  line-height: 1.7;
  color: var(--text-muted);
  max-width: 700px;
  margin: 0 auto;
}

/* ─── Study Topbar (Progress + Actions) ──────────────────────────── */

.study-topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 20px 0;
  margin-bottom: 20px;
  border-bottom: 1px solid var(--border);
  flex-wrap: wrap;
}

.progress-block {
  display: flex;
  align-items: center;
  gap: 14px;
  flex: 1;
}

.progress-track {
  flex: 1;
  max-width: 260px;
  height: 6px;
  background: var(--border);
  border-radius: 100px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: var(--accent);
  border-radius: 100px;
  transition: width 0.4s ease;
}

.progress-text {
  font-size: 0.85rem;
  color: var(--text-muted);
  white-space: nowrap;
}

.study-actions {
  display: flex;
  gap: 12px;
}

.action-btn {
  padding: 6px 16px;
  font-family: var(--font-body);
  font-size: 0.8rem;
  font-weight: 600;
  border: 1px solid var(--border);
  border-radius: 100px;
  background: var(--white);
  color: var(--text);
  cursor: pointer;
  transition: all 0.2s;
  white-space: nowrap;
}

.action-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-light);
}

/* ─── Trophy Area ────────────────────────────────────────────────── */

.trophy-area {
  padding: 14px 20px;
  margin-bottom: 28px;
  border-radius: 12px;
  background: var(--accent-light);
  border: 1px solid #BBF7D0;
  font-size: 0.9rem;
  color: var(--accent-hover);
}

.trophy-area.complete {
  background: #FEF9C3;
  border-color: #FDE047;
  color: #854D0E;
}

.trophy-area.partial {
  background: #F0FDF4;
  border-color: #BBF7D0;
}

/* ─── Table of Contents ──────────────────────────────────────────── */

.toc-section {
  margin-bottom: 36px;
  padding: 0;
}

.toc-section h3 {
  font-family: var(--font-heading);
  font-size: 1.4rem;
  font-weight: 400;
  margin-bottom: 16px;
}

.toc-list {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.toc-item {
  padding: 8px 14px;
  font-size: 0.9rem;
  color: var(--text);
  text-decoration: none;
  border-radius: 8px;
  background: var(--bg);
  border: 1px solid var(--border);
  transition: all 0.2s;
  display: block;
}

.toc-item:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-light);
}

/* ─── Intro Section ──────────────────────────────────────────────── */

.intro-section {
  margin-bottom: 40px;
  padding: 0;
}

.intro-section p {
  font-size: 1rem;
  line-height: 1.85;
  color: var(--text);
  margin-bottom: 16px;
}

/* ─── Sections List (Accordions) ─────────────────────────────────── */

.sections-list {
  margin-bottom: 48px;
}

.study-section {
  margin-bottom: 14px;
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
  background: var(--white);
  transition: border-color 0.2s;
}

.study-section:hover {
  border-color: #CBD5E1;
}

.study-section[open] {
  border-color: var(--accent);
}

.section-summary {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 18px 22px;
  cursor: pointer;
  list-style: none;
  user-select: none;
  -webkit-user-select: none;
}

.section-summary::-webkit-details-marker {
  display: none;
}

.section-num {
  width: 34px;
  height: 34px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 100px;
  background: var(--accent-light);
  color: var(--accent);
  font-size: 0.8rem;
  font-weight: 700;
  flex-shrink: 0;
}

.study-section.completed .section-num {
  background: var(--accent);
  color: var(--white);
}

.section-label {
  flex: 1;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text);
  line-height: 1.4;
}

.section-toggle {
  color: var(--text-muted);
  font-size: 0.8rem;
  transition: transform 0.2s;
}

.study-section[open] .section-toggle {
  transform: rotate(90deg);
}

/* ─── Section Content ────────────────────────────────────────────── */

.section-content {
  padding: 4px 22px 24px;
  border-top: 1px solid var(--border);
}

.section-content p {
  font-size: 1rem;
  line-height: 1.85;
  color: var(--text);
  margin-bottom: 18px;
}

.section-content p:last-child {
  margin-bottom: 0;
}

/* ─── Key Takeaways ──────────────────────────────────────────────── */

.takeaways-section {
  margin-bottom: 48px;
  padding: 32px;
  background: var(--accent-light);
  border-radius: 16px;
  border: 1px solid #BBF7D0;
}

.takeaways-section h2 {
  font-family: var(--font-heading);
  font-size: 1.6rem;
  font-weight: 400;
  margin-bottom: 20px;
  color: var(--text);
}

.takeaways-section ul {
  padding-left: 24px;
}

.takeaways-section li {
  font-size: 0.95rem;
  line-height: 1.8;
  color: var(--text);
  margin-bottom: 12px;
  list-style-type: disc;
}

.takeaways-section li::marker {
  color: var(--accent);
}

.takeaways-section li:last-child {
  margin-bottom: 0;
}

/* ─── FAQ Section ────────────────────────────────────────────────── */

.faq-section {
  margin-bottom: 48px;
  padding: 0;
}

.faq-section h2 {
  font-family: var(--font-heading);
  font-size: 1.6rem;
  font-weight: 400;
  margin-bottom: 24px;
  color: var(--text);
}

.faq-item {
  margin-bottom: 20px;
  padding: 20px 24px;
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: 12px;
}

.faq-item h3 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 10px;
  line-height: 1.5;
}

.faq-item p {
  font-size: 0.95rem;
  line-height: 1.8;
  color: var(--text);
}

/* ─── Related Topics ──────────────────────────────────────────────── */

.related-section {
  margin-bottom: 48px;
  padding: 0;
}

.related-section h2 {
  font-family: var(--font-heading);
  font-size: 1.6rem;
  font-weight: 400;
  margin-bottom: 20px;
  color: var(--text);
}

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

.topic-card {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 18px 20px;
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: 12px;
  text-decoration: none;
  transition: all 0.2s;
}

.topic-card:hover {
  border-color: var(--accent);
  box-shadow: 0 2px 12px rgba(22, 163, 74, 0.08);
  transform: translateY(-2px);
}

.topic-number {
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: 0.05em;
}

.topic-title {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text);
  line-height: 1.4;
}

/* ─── Hero Section (Homepage) ────────────────────────────────────── */

.hero {
  padding: 60px 0 48px;
  text-align: center;
}

.hero-title {
  font-family: var(--font-heading);
  font-size: 2.8rem;
  font-weight: 400;
  line-height: 1.15;
  color: var(--text);
  margin-bottom: 20px;
  max-width: 720px;
  margin-left: auto;
  margin-right: auto;
}

.hero-subtitle {
  font-size: 1.1rem;
  line-height: 1.7;
  color: var(--text-muted);
  max-width: 600px;
  margin: 0 auto 32px;
}

.hero-actions {
  display: flex;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
}

.hero-btn {
  display: inline-block;
  padding: 14px 32px;
  font-family: var(--font-body);
  font-size: 0.95rem;
  font-weight: 600;
  text-decoration: none;
  border-radius: 100px;
  transition: all 0.2s;
}

.hero-btn.primary {
  background: var(--accent);
  color: var(--white);
  border: 2px solid var(--accent);
}

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

.hero-btn.secondary {
  background: var(--white);
  color: var(--text);
  border: 2px solid var(--border);
}

.hero-btn.secondary:hover {
  border-color: var(--accent);
  color: var(--accent);
}

/* ─── Topics Section (Homepage Grid) ─────────────────────────────── */

.topics-section {
  padding: 48px 0;
}

.section-heading {
  font-family: var(--font-heading);
  font-size: 1.8rem;
  font-weight: 400;
  margin-bottom: 28px;
  color: var(--text);
}

/* ─── CTA Section ────────────────────────────────────────────────── */

.cta-section {
  position: relative;
  margin: 48px 0;
  padding: 48px 40px;
  text-align: center;
  background: linear-gradient(135deg, var(--accent), var(--accent-hover));
  border-radius: 20px;
  overflow: hidden;
}

.cta-bg-circles {
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: radial-gradient(circle at 10% 20%, rgba(255,255,255,0.12) 0%, transparent 50%),
              radial-gradient(circle at 90% 80%, rgba(255,255,255,0.08) 0%, transparent 50%);
}

.cta-section h3 {
  position: relative;
  font-family: var(--font-heading);
  font-size: 1.8rem;
  font-weight: 400;
  color: var(--white);
  margin-bottom: 14px;
}

.cta-section p {
  position: relative;
  font-size: 1rem;
  color: rgba(255,255,255,0.9);
  margin-bottom: 24px;
}

.cta-button {
  position: relative;
  display: inline-block;
  padding: 14px 36px;
  font-family: var(--font-body);
  font-size: 0.95rem;
  font-weight: 600;
  text-decoration: none;
  color: var(--accent);
  background: var(--white);
  border-radius: 100px;
  transition: all 0.2s;
}

.cta-button:hover {
  box-shadow: 0 4px 20px rgba(0,0,0,0.15);
  transform: translateY(-2px);
}

/* ─── Footer ─────────────────────────────────────────────────────── */

.site-footer {
  margin-top: 64px;
  padding: 32px 0 20px;
  border-top: 1px solid var(--border);
  background: var(--white);
}

.footer-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 20px;
  margin-bottom: 20px;
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 10px;
}

.footer-logo {
  height: 20px;
  width: auto;
  border-radius: 8px;
}

.footer-name {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.footer-links {
  display: flex;
  gap: 24px;
}

.footer-links a {
  text-decoration: none;
  font-size: 0.85rem;
  color: var(--text-muted);
  transition: color 0.2s;
}

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

.footer-bottom {
  text-align: center;
  padding-top: 20px;
  border-top: 1px solid var(--border);
}

.footer-bottom p {
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* ─── Index Page Topic Grid ──────────────────────────────────────── */

.topic-number {
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: 0.05em;
  display: block;
  margin-bottom: 4px;
}

/* ─── Responsive ─────────────────────────────────────────────────── */

@media (max-width: 768px) {
  .container { padding: 0 16px; }
  .article-title { font-size: 1.8rem; }
  .hero-title { font-size: 2rem; }
  .cover-section { padding: 32px 0 24px; }
  .section-summary { padding: 14px 16px; }
  .section-content { padding: 4px 16px 20px; }
  .study-topbar { flex-direction: row; flex-wrap: wrap; gap: 12px; }
  .progress-block { flex: 1; min-width: 140px; }
  .progress-track { max-width: 120px; }
  .study-actions { gap: 8px; }
  .topics-grid { grid-template-columns: 1fr; }
  .cta-section { padding: 36px 24px; }
  .cta-section h3 { font-size: 1.4rem; }
  .takeaways-section { padding: 24px; }
  .footer-content { flex-direction: column; text-align: center; }
  .hero { padding: 40px 0 32px; }
  .main-nav a { font-size: 0.82rem; }
  .banner { padding: 10px 0; }
}

@media (max-width: 480px) {
  .container { padding: 0 12px; }
  .article-title { font-size: 1.5rem; }
  .hero-title { font-size: 1.6rem; }
  .hero-subtitle { font-size: 0.95rem; }
  .cover-badge { font-size: 0.7rem; padding: 4px 14px; }
  .section-label { font-size: 0.88rem; }
  .toc-list { gap: 4px; }
  .toc-item { padding: 6px 12px; font-size: 0.85rem; }
  .faq-item { padding: 16px; }
  .faq-section h2 { font-size: 1.3rem; }
  .takeaways-section h2 { font-size: 1.3rem; }
  .related-section h2 { font-size: 1.3rem; }
  .topics-grid { gap: 10px; }
  .topic-card { padding: 14px 16px; }
  .cta-section { margin: 32px 0; padding: 28px 16px; border-radius: 14px; }
  .cta-section h3 { font-size: 1.2rem; }
  .cta-button { padding: 12px 28px; font-size: 0.9rem; }
  .footer-content { gap: 12px; }
  .site-footer { margin-top: 40px; padding: 24px 0 16px; }
  .section-content p { font-size: 0.9rem; }
  .study-topbar { gap: 10px; }
  .action-btn { padding: 5px 12px; font-size: 0.75rem; }
  .progress-text { font-size: 0.78rem; }
  .cover-section { padding: 24px 0 16px; }
  .hero { padding: 28px 0 24px; }
  .banner { padding: 8px 0; }
  .logo-link { font-size: 0.9rem; }
  .logo { height: 16px; border-radius: 7px; }
  .main-nav { gap: 16px; }
  .main-nav a { font-size: 0.75rem; }
}