/* ============================================
   Landing Page Styles
   AI: Promise & Peril — Study Guide
   ============================================ */

html { scroll-behavior: smooth; }

.hero {
  background: linear-gradient(135deg, #0f172a 0%, #7c3aed 100%);
  color: #fff;
  text-align: center;
  padding: 80px 24px;
}

.hero__title {
  font-family: Georgia, "Times New Roman", serif;
  font-size: 3rem;
  font-weight: 700;
  margin: 0 0 12px;
  letter-spacing: -0.02em;
}

.hero__subtitle {
  font-family: Georgia, "Times New Roman", serif;
  font-size: 1.35rem;
  font-weight: 400;
  margin: 0 0 8px;
  opacity: 0.92;
}

.hero__author {
  font-size: 1.1rem;
  margin: 0 0 4px;
  opacity: 0.85;
}

.hero__meta {
  font-size: 0.95rem;
  margin: 0 0 36px;
  opacity: 0.7;
}

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

.btn {
  display: inline-block;
  padding: 14px 32px;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 600;
  text-decoration: none;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  cursor: pointer;
  border: none;
}

.btn:hover { transform: translateY(-2px); }

.btn--primary {
  background: #fff;
  color: #0f172a;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

.btn--primary:hover {
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.2);
}

.btn--secondary {
  background: rgba(255, 255, 255, 0.15);
  color: #fff;
  border: 2px solid rgba(255, 255, 255, 0.5);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.btn--secondary:hover {
  background: rgba(255, 255, 255, 0.25);
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.15);
}

/* --- Sections --- */

.section {
  padding: 64px 24px;
  max-width: 1200px;
  margin: 0 auto;
}

.section__heading {
  font-family: Georgia, "Times New Roman", serif;
  font-size: 2rem;
  font-weight: 700;
  text-align: center;
  margin: 0 0 8px;
  color: #1e293b;
}

.section__description {
  text-align: center;
  color: #64748b;
  margin: 0 0 40px;
  font-size: 1.05rem;
}

.section__heading::after {
  content: "";
  display: block;
  width: 48px;
  height: 3px;
  background: linear-gradient(90deg, #0f172a, #7c3aed);
  margin: 12px auto 0;
  border-radius: 2px;
}

/* --- Grid --- */

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 24px;
}

/* --- Topic Cards --- */

.topic-card {
  background: #fff;
  border-radius: 10px;
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.08), 0 2px 8px rgba(0, 0, 0, 0.04);
  padding: 24px 24px 24px 20px;
  border-left: 4px solid transparent;
  text-decoration: none;
  color: inherit;
  display: block;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.topic-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1), 0 8px 24px rgba(0, 0, 0, 0.08);
  text-decoration: none;
}

.topic-card__number {
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin: 0 0 4px;
  opacity: 0.6;
  display: block;
}

.topic-card__title {
  font-family: Georgia, "Times New Roman", serif;
  font-size: 1.2rem;
  font-weight: 700;
  margin: 0 0 8px;
  color: #1e293b;
}

.topic-card__desc {
  font-size: 0.92rem;
  color: #64748b;
  margin: 0 0 12px;
  line-height: 1.5;
}

.topic-card__section {
  font-size: 0.8rem;
  color: #94a3b8;
  font-weight: 500;
}

/* Topic card border colors */
.topic-card--1  { border-left-color: #7c3aed; }
.topic-card--2  { border-left-color: #10b981; }
.topic-card--3  { border-left-color: #3b82f6; }
.topic-card--4  { border-left-color: #f59e0b; }
.topic-card--5  { border-left-color: #06b6d4; }
.topic-card--6  { border-left-color: #ef4444; }
.topic-card--7  { border-left-color: #ec4899; }
.topic-card--8  { border-left-color: #8b5cf6; }
.topic-card--9  { border-left-color: #f97316; }
.topic-card--10 { border-left-color: #14b8a6; }
.topic-card--11 { border-left-color: #e11d48; }
.topic-card--12 { border-left-color: #6366f1; }
.topic-card--13 { border-left-color: #0ea5e9; }
.topic-card--14 { border-left-color: #a855f7; }
.topic-card--15 { border-left-color: #dc2626; }
.topic-card--16 { border-left-color: #f59e0b; }
.topic-card--17 { border-left-color: #10b981; }
.topic-card--18 { border-left-color: #f43f5e; }
.topic-card--19 { border-left-color: #3b82f6; }
.topic-card--20 { border-left-color: #8b5cf6; }
.topic-card--21 { border-left-color: #06b6d4; }
.topic-card--22 { border-left-color: #ef4444; }
.topic-card--23 { border-left-color: #84cc16; }
.topic-card--24 { border-left-color: #6366f1; }
.topic-card--25 { border-left-color: #ec4899; }

/* --- Key Themes Cards --- */

.theme-card {
  background: #fff;
  border-radius: 10px;
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.08), 0 2px 8px rgba(0, 0, 0, 0.04);
  padding: 28px 24px;
  border-top: 4px solid transparent;
  text-decoration: none;
  color: inherit;
  display: block;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.theme-card:hover {
  transform: scale(1.02);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1), 0 8px 24px rgba(0, 0, 0, 0.08);
}

.theme-card__icon {
  font-size: 2rem;
  margin: 0 0 12px;
  display: block;
}

.theme-card__title {
  font-family: Georgia, "Times New Roman", serif;
  font-size: 1.15rem;
  font-weight: 700;
  margin: 0 0 8px;
  color: #1e293b;
}

.theme-card__desc {
  font-size: 0.92rem;
  color: #64748b;
  line-height: 1.5;
  margin: 0;
}

.theme-card--purple { border-top-color: #7c3aed; }
.theme-card--green  { border-top-color: #10b981; }
.theme-card--blue   { border-top-color: #3b82f6; }
.theme-card--amber  { border-top-color: #f59e0b; }
.theme-card--rose   { border-top-color: #f43f5e; }
.theme-card--indigo { border-top-color: #6366f1; }

/* --- Footer --- */

.footer {
  text-align: center;
  padding: 32px 24px;
  color: #94a3b8;
  font-size: 0.9rem;
  border-top: 1px solid #e2e8f0;
}

/* --- Responsive --- */

@media (max-width: 640px) {
  .hero { padding: 56px 20px; }
  .hero__title { font-size: 2rem; }
  .hero__subtitle { font-size: 1.1rem; }
  .grid { grid-template-columns: 1fr; }
  .section { padding: 48px 16px; }
  .section__heading { font-size: 1.6rem; }
}