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

:root {
  --warm: #c2410c;
  --warm-light: #ea580c;
  --warm-bg: rgba(194, 65, 12, 0.06);
  --paper: #faf8f5;
  --paper-dark: #f0ece6;
  --paper-shadow: #e5ddd3;
  --text: #2c2417;
  --text-muted: #7c6f5e;
  --border: #e0d8cc;
  --font-serif: 'Libre Baskerville', serif;
  --font-sans: 'Source Sans 3', sans-serif;
}

body {
  font-family: var(--font-sans);
  background: var(--paper);
  color: var(--text);
  overflow-x: hidden;
  line-height: 1.7;
}

/* Paper Texture via subtle noise pattern */
.paper-texture {
  position: absolute;
  inset: 0;
  opacity: 0.3;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noise'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noise)' opacity='0.04'/%3E%3C/svg%3E");
  pointer-events: none;
}

/* Header */
.accordion-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(250, 248, 245, 0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}

.ah-inner {
  max-width: 900px;
  margin: 0 auto;
  padding: 14px 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.ah-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: 1rem;
  color: var(--text);
}

.ah-brand img {
  width: 32px;
  height: 32px;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.08);
}

.ah-download {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 20px;
  background: var(--warm);
  color: #fff;
  text-decoration: none;
  border-radius: 6px;
  font-size: 0.85rem;
  font-weight: 600;
  transition: background 0.3s;
}

.ah-download:hover {
  background: var(--warm-light);
}

/* Hero */
.hero-accordion {
  position: relative;
  padding: 140px 2rem 80px;
  text-align: center;
  background: linear-gradient(180deg, var(--paper-dark) 0%, var(--paper) 100%);
}

.hero-fold-content {
  position: relative;
  z-index: 1;
  max-width: 580px;
  margin: 0 auto;
}

.hf-icon {
  width: 96px;
  height: 96px;
  margin: 0 auto 1.5rem;
  border-radius: 20px;
  overflow: hidden;
  box-shadow: 0 8px 30px rgba(0,0,0,0.12);
  border: 3px solid #fff;
}

.hf-icon img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.hero-accordion h1 {
  font-family: var(--font-serif);
  font-size: clamp(2.5rem, 6vw, 3.5rem);
  font-weight: 700;
  color: var(--text);
  margin-bottom: 1rem;
  line-height: 1.2;
}

.hero-accordion p {
  color: var(--text-muted);
  font-size: 1.05rem;
  max-width: 460px;
  margin: 0 auto 2rem;
  line-height: 1.8;
}

/* Paper Button */
.paper-btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 14px 32px;
  background: var(--warm);
  color: #fff;
  text-decoration: none;
  border-radius: 8px;
  font-weight: 600;
  font-size: 0.95rem;
  border: none;
  cursor: pointer;
  transition: all 0.3s;
  box-shadow: 0 4px 16px rgba(194, 65, 12, 0.2);
}

.paper-btn:hover {
  background: var(--warm-light);
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(194, 65, 12, 0.3);
}

.paper-btn.large {
  padding: 18px 44px;
  font-size: 1.1rem;
}

/* Accordion Main */
.accordion-main {
  max-width: 900px;
  margin: 0 auto;
  padding: 2rem;
}

/* Accordion Panel */
.accordion-panel {
  margin-bottom: 4px;
  border: 1px solid var(--border);
  border-radius: 8px;
  overflow: hidden;
  background: #fff;
  box-shadow: 0 1px 3px rgba(0,0,0,0.04);
  transition: box-shadow 0.3s;
}

.accordion-panel:hover {
  box-shadow: 0 4px 16px rgba(0,0,0,0.06);
}

.panel-header {
  width: 100%;
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1.25rem 1.5rem;
  background: none;
  border: none;
  cursor: pointer;
  font-family: var(--font-sans);
  font-size: 1rem;
  color: var(--text);
  text-align: left;
  transition: background 0.3s;
}

.panel-header:hover {
  background: var(--warm-bg);
}

.panel-number {
  font-family: var(--font-serif);
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--warm);
  min-width: 36px;
}

.panel-title {
  flex: 1;
  font-weight: 600;
  font-size: 1.05rem;
}

.panel-arrow {
  font-size: 1.2rem;
  color: var(--text-muted);
  transition: transform 0.3s;
}

.accordion-panel.expanded .panel-arrow {
  transform: rotate(180deg);
}

/* Panel Body */
.panel-body {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.5s cubic-bezier(0.4, 0, 0.2, 1);
  position: relative;
}

.accordion-panel.expanded .panel-body {
  max-height: 2000px;
}

/* Fold Shadow */
.fold-shadow {
  height: 8px;
  background: linear-gradient(180deg, rgba(0,0,0,0.06) 0%, transparent 100%);
  margin: 0 1.5rem;
}

.panel-content {
  padding: 1rem 1.5rem 2rem;
}

.panel-content.center {
  text-align: center;
}

.panel-content p {
  color: var(--text-muted);
  font-size: 1rem;
  line-height: 1.9;
}

.panel-content h2 {
  font-family: var(--font-serif);
  font-size: 1.8rem;
  margin-bottom: 0.5rem;
  color: var(--text);
}

.dl-sub {
  margin-bottom: 1.5rem;
}

/* Features */
.fold-features {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.fold-feat {
  display: flex;
  gap: 1rem;
  align-items: flex-start;
  padding: 1.25rem;
  border-radius: 8px;
  background: var(--paper);
  border: 1px solid var(--border);
  transition: border-color 0.3s, transform 0.3s;
}

.fold-feat:hover {
  border-color: var(--warm);
  transform: translateX(4px);
}

.ff-marker {
  color: var(--warm);
  font-size: 0.8rem;
  margin-top: 3px;
  flex-shrink: 0;
}

.fold-feat h3 {
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 0.3rem;
  color: var(--text);
}

.fold-feat p {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.7;
}

/* Gallery */
.fold-gallery {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1rem;
}

.fold-thumb {
  border-radius: 8px;
  overflow: hidden;
  border: 1px solid var(--border);
  box-shadow: 0 2px 8px rgba(0,0,0,0.06);
  transition: transform 0.3s, box-shadow 0.3s;
}

.fold-thumb:hover {
  transform: scale(1.02);
  box-shadow: 0 8px 24px rgba(0,0,0,0.1);
}

.fold-thumb img {
  width: 100%;
  display: block;
}

/* FAQ */
.fold-faq {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.ffaq-item {
  padding: 1rem 1.25rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  cursor: pointer;
  background: var(--paper);
  transition: border-color 0.3s;
}

.ffaq-item:hover {
  border-color: var(--warm);
}

.ffaq-q {
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--text);
}

.ffaq-a {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease;
  color: var(--text-muted);
  font-size: 0.9rem;
  line-height: 1.8;
}

.ffaq-item.open .ffaq-a {
  max-height: 200px;
  margin-top: 0.6rem;
}

.ffaq-a a {
  color: var(--warm);
  text-decoration: none;
  font-weight: 600;
}

.ffaq-a a:hover {
  text-decoration: underline;
}

/* Footer */
.accordion-footer {
  border-top: 1px solid var(--border);
  padding: 2.5rem 2rem;
  background: var(--paper-dark);
}

.af-inner {
  max-width: 900px;
  margin: 0 auto;
  text-align: center;
}

.af-inner nav {
  display: flex;
  justify-content: center;
  gap: 2rem;
  margin-bottom: 1rem;
}

.af-inner nav a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.85rem;
  font-weight: 500;
  transition: color 0.3s;
}

.af-inner nav a:hover {
  color: var(--warm);
}

.af-inner p {
  color: #b0a898;
  font-size: 0.8rem;
}

/* Responsive */
@media (max-width: 768px) {
  .accordion-main {
    padding: 1rem;
  }

  .panel-content {
    padding: 1rem 1rem 1.5rem;
  }

  .fold-gallery {
    grid-template-columns: 1fr;
  }

  .fold-feat {
    flex-direction: column;
    gap: 0.5rem;
  }
}

@media (max-width: 480px) {
  .hero-accordion h1 {
    font-size: 2rem;
  }

  .panel-header {
    padding: 1rem;
  }

  .panel-number {
    font-size: 1.1rem;
  }

  .hf-icon {
    width: 72px;
    height: 72px;
  }

  .panel-content h2 {
    font-size: 1.5rem;
  }
}