/* ===========================================
   Hero Section
   =========================================== */
.hero-section {
  text-align: center;
  padding: 5rem 2rem 4rem;
  margin: -0.8rem -0.8rem 3rem;
  background: linear-gradient(135deg, #1a0533 0%, #2d1b69 40%, #0d4a6b 100%);
  position: relative;
  overflow: hidden;
}

.hero-section::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background:
    radial-gradient(ellipse at 50% 50%, rgba(0, 188, 212, 0.07) 0%, transparent 55%),
    radial-gradient(ellipse at 80% 20%, rgba(156, 39, 176, 0.12) 0%, transparent 45%);
  animation: heroGlow 10s ease-in-out infinite alternate;
  pointer-events: none;
}

@keyframes heroGlow {
  0%   { transform: scale(1)   rotate(0deg);  opacity: 0.5; }
  100% { transform: scale(1.1) rotate(8deg);  opacity: 1;   }
}

.hero-badge {
  display: inline-block;
  background: rgba(0, 188, 212, 0.12);
  border: 1px solid rgba(0, 188, 212, 0.45);
  border-radius: 3rem;
  padding: 0.3rem 1.2rem;
  font-size: 0.78rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: #80deea;
  margin-bottom: 1.6rem;
  position: relative;
  z-index: 1;
}

.hero-title {
  font-size: clamp(2rem, 5vw, 3.6rem);
  font-weight: 900;
  line-height: 1.15;
  margin: 0 auto 1.5rem;
  max-width: 820px;
  background: linear-gradient(135deg, #ffffff 0%, #b2ebf2 50%, #80cbc4 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  position: relative;
  z-index: 1;
}

.hero-subtitle {
  font-size: 1.15rem;
  max-width: 640px;
  margin: 0 auto 2.5rem;
  color: rgba(255, 255, 255, 0.72);
  line-height: 1.75;
  position: relative;
  z-index: 1;
}

.hero-actions {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
  position: relative;
  z-index: 1;
}

.hero-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.85rem 2.2rem;
  border-radius: 3rem;
  font-weight: 700;
  font-size: 0.95rem;
  text-decoration: none !important;
  transition: all 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
  cursor: pointer;
}

.hero-btn-primary {
  background: linear-gradient(135deg, #00bcd4, #00897b);
  color: white !important;
  box-shadow: 0 4px 20px rgba(0, 188, 212, 0.35);
}

.hero-btn-primary:hover {
  transform: translateY(-3px);
  box-shadow: 0 10px 35px rgba(0, 188, 212, 0.55);
}

.hero-btn-secondary {
  background: rgba(255, 255, 255, 0.08);
  color: rgba(255,255,255,0.9) !important;
  border: 1px solid rgba(255, 255, 255, 0.28);
  backdrop-filter: blur(8px);
}

.hero-btn-secondary:hover {
  background: rgba(255, 255, 255, 0.16);
  transform: translateY(-3px);
}

/* ===========================================
   Stats Row
   =========================================== */
.stats-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 1rem;
  margin: 2.5rem 0;
}

.stat-card {
  text-align: center;
  padding: 1.5rem 1rem;
  border-radius: 1rem;
  background: var(--md-code-bg-color);
  border: 1px solid var(--md-default-fg-color--lightest);
  transition: all 0.25s ease;
}

.stat-card:hover {
  transform: translateY(-4px);
  border-color: var(--md-accent-fg-color);
  box-shadow: 0 8px 28px rgba(0, 0, 0, 0.1);
}

.stat-number {
  font-size: 2.2rem;
  font-weight: 900;
  color: var(--md-accent-fg-color);
  line-height: 1;
}

.stat-label {
  font-size: 0.78rem;
  color: var(--md-default-fg-color--light);
  margin-top: 0.4rem;
  text-transform: uppercase;
  letter-spacing: 0.07em;
}

/* ===========================================
   Whitepaper Cards
   =========================================== */
.papers-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
  margin: 2rem 0;
}

.paper-card {
  border-radius: 1.2rem;
  padding: 1.75rem;
  background: var(--md-code-bg-color);
  border: 1px solid var(--md-default-fg-color--lightest);
  transition: all 0.3s cubic-bezier(0.34, 1.1, 0.64, 1);
  position: relative;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.paper-card::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 3px;
  background: linear-gradient(90deg, var(--md-primary-fg-color), var(--md-accent-fg-color));
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.3s ease;
}

.paper-card:hover::after {
  transform: scaleX(1);
}

.paper-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 16px 45px rgba(0, 0, 0, 0.14);
  border-color: var(--md-accent-fg-color);
}

.paper-icon {
  font-size: 2.2rem;
  line-height: 1;
}

.paper-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.paper-tag {
  display: inline-block;
  padding: 0.15rem 0.65rem;
  border-radius: 2rem;
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  background: rgba(0, 150, 136, 0.12);
  color: var(--md-accent-fg-color);
  border: 1px solid rgba(0, 150, 136, 0.3);
}

.paper-card h3 {
  font-size: 1.1rem;
  font-weight: 700;
  margin: 0;
  line-height: 1.35;
}

.paper-card p {
  font-size: 0.9rem;
  color: var(--md-default-fg-color--light);
  margin: 0;
  flex: 1;
  line-height: 1.6;
}

.read-link {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--md-accent-fg-color) !important;
  text-decoration: none !important;
  margin-top: 0.5rem;
  transition: gap 0.2s ease;
}

.read-link:hover {
  gap: 0.6rem;
}

/* ===========================================
   Topic Grid
   =========================================== */
.topic-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
  gap: 0.75rem;
  margin: 1.5rem 0;
}

.topic-item {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.75rem 1rem;
  border-radius: 0.75rem;
  background: var(--md-code-bg-color);
  border: 1px solid var(--md-default-fg-color--lightest);
  font-size: 0.88rem;
  font-weight: 500;
  transition: all 0.2s ease;
  cursor: default;
}

.topic-item:hover {
  border-color: var(--md-accent-fg-color);
  background: rgba(0, 188, 212, 0.06);
  transform: translateY(-2px);
}

/* ===========================================
   Gradient Banner
   =========================================== */
.gradient-banner {
  padding: 2.2rem 2rem;
  border-radius: 1.2rem;
  background: linear-gradient(135deg, #4a148c, #00695c);
  color: white;
  margin: 3rem 0;
  text-align: center;
}

.gradient-banner h2,
.gradient-banner h3,
.gradient-banner p,
.gradient-banner a {
  color: white !important;
}

.gradient-banner h2 {
  margin-top: 0;
  font-size: 1.6rem;
}

.gradient-banner a {
  font-weight: 700;
  text-decoration: underline !important;
  opacity: 0.9;
}

.gradient-banner a:hover {
  opacity: 1;
}

/* ===========================================
   Whitepaper Page Header
   =========================================== */
.paper-header {
  padding: 2rem;
  border-radius: 1.2rem;
  background: linear-gradient(135deg, rgba(74, 20, 140, 0.08), rgba(0, 188, 212, 0.08));
  border: 1px solid var(--md-default-fg-color--lightest);
  margin-bottom: 2.5rem;
}

.paper-meta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 1.2rem;
  margin-top: 1rem;
  font-size: 0.85rem;
  color: var(--md-default-fg-color--light);
}

.paper-meta-item {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
}

/* ===========================================
   Takeaway Grid
   =========================================== */
.takeaway-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
  margin: 1.5rem 0;
}

.takeaway-item {
  padding: 1.25rem;
  border-radius: 0.75rem;
  border-left: 4px solid var(--md-accent-fg-color);
  background: var(--md-code-bg-color);
  font-size: 0.9rem;
  line-height: 1.55;
}

.takeaway-item strong {
  display: block;
  margin-bottom: 0.3rem;
  color: var(--md-accent-fg-color);
  font-size: 0.82rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

/* ===========================================
   Timeline
   =========================================== */
.timeline {
  position: relative;
  padding-left: 2.2rem;
  margin: 1.5rem 0;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 0.5rem;
  top: 0.6rem;
  bottom: 0.6rem;
  width: 2px;
  background: linear-gradient(to bottom, var(--md-primary-fg-color), var(--md-accent-fg-color));
}

.timeline-item {
  position: relative;
  margin-bottom: 1.25rem;
  padding: 1rem 1.25rem;
  background: var(--md-code-bg-color);
  border-radius: 0.75rem;
  border: 1px solid var(--md-default-fg-color--lightest);
  transition: border-color 0.2s ease;
}

.timeline-item:hover {
  border-color: var(--md-accent-fg-color);
}

.timeline-item::before {
  content: '';
  position: absolute;
  left: -1.7rem;
  top: 1.1rem;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--md-accent-fg-color);
  border: 2px solid var(--md-default-bg-color);
}

.timeline-year {
  font-size: 0.75rem;
  font-weight: 800;
  color: var(--md-accent-fg-color);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: 0.3rem;
}

/* ===========================================
   Overview Cards (whitepapers index)
   =========================================== */
.overview-card {
  display: flex;
  gap: 1.2rem;
  align-items: flex-start;
  padding: 1.5rem;
  border-radius: 1rem;
  background: var(--md-code-bg-color);
  border: 1px solid var(--md-default-fg-color--lightest);
  margin-bottom: 1.25rem;
  transition: all 0.25s ease;
  text-decoration: none;
}

.overview-card:hover {
  border-color: var(--md-accent-fg-color);
  transform: translateX(4px);
  box-shadow: 0 6px 20px rgba(0,0,0,0.08);
}

.overview-card-icon {
  font-size: 2.5rem;
  flex-shrink: 0;
  line-height: 1;
}

.overview-card-body h3 {
  margin: 0 0 0.4rem;
  font-size: 1.05rem;
  color: var(--md-default-fg-color);
}

.overview-card-body p {
  margin: 0;
  font-size: 0.88rem;
  color: var(--md-default-fg-color--light);
  line-height: 1.55;
}

/* ===========================================
   Responsive
   =========================================== */
@media (max-width: 640px) {
  .hero-section {
    padding: 3rem 1.25rem 2.5rem;
  }

  .hero-title {
    font-size: 2rem;
  }

  .hero-subtitle {
    font-size: 1rem;
  }

  .paper-header {
    padding: 1.25rem;
  }
}