/* ============================================
   汉字演化史 · 水墨风格网站
   Ink-Wash Painting Style for Chinese Character Evolution
   ============================================ */

/* --- CSS Variables --- */
:root {
  --ink-black: #1a1a1a;
  --ink-dark: #2c2c2c;
  --ink-medium: #555;
  --ink-light: #8a8a8a;
  --ink-faint: rgba(0, 0, 0, 0.06);
  --paper: #f7f3ea;
  --paper-light: #faf8f2;
  --paper-dark: #e8e2d0;
  --seal-red: #c23b22;
  --seal-red-light: #e05a3a;
  --gold: #b8965a;
  --gold-light: #d4b87a;
  /*
   * Font stacks: loaded web fonts first, system fonts as fallbacks.
   * Three tiers for visual hierarchy:
   *   --font-heading: Kai-style hand-writing → ink-wash calligraphic feel
   *   --font-body:    Song-style (Noto Serif SC) → readable for long text
   *   --font-accent:  Running script (Ma Shan Zheng) → decorative/seal
   * Every primary font is loaded via Google Fonts for cross-platform consistency.
   */
  --font-heading: 'ZCOOL XiaoWei', 'STKaiti', 'KaiTi', '楷体', 'Noto Serif SC', serif;
  --font-body: 'Noto Serif SC', 'STSong', 'SimSun', '宋体', 'Source Han Serif SC', serif;
  --font-accent: 'Ma Shan Zheng', 'STLiti', 'LiSu', '隶书', 'KaiTi', serif;
  --font-glyph: 'ZCOOL XiaoWei', 'Ma Shan Zheng', 'STKaiti', 'KaiTi', '楷体', 'Noto Serif SC', serif;
  --transition-slow: 0.6s cubic-bezier(0.22, 1, 0.36, 1);
  --transition-medium: 0.4s cubic-bezier(0.22, 1, 0.36, 1);
  --transition-fast: 0.2s ease-out;
  --shadow-ink: 0 2px 20px rgba(0, 0, 0, 0.08);
  --shadow-ink-lg: 0 8px 40px rgba(0, 0, 0, 0.12);
}

/* --- Reset & Base --- */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
}

body {
  font-family: var(--font-body);
  background-color: var(--paper);
  color: var(--ink-dark);
  line-height: 1.8;
  font-size: 16px;
  overflow-x: hidden;
  min-height: 100vh;
}

/* --- Rice Paper Texture (background) --- */
body::before {
  content: '';
  position: fixed;
  top: 0; left: 0; right: 0; bottom: 0;
  background:
    /* Paper warm base */
    radial-gradient(ellipse at 20% 50%, rgba(139, 119, 90, 0.04) 0%, transparent 50%),
    radial-gradient(ellipse at 80% 20%, rgba(139, 119, 90, 0.03) 0%, transparent 50%),
    radial-gradient(ellipse at 50% 80%, rgba(180, 150, 90, 0.03) 0%, transparent 50%),
    /* Fiber texture - subtle horizontal lines */
    repeating-linear-gradient(
      90deg,
      transparent,
      transparent 3px,
      rgba(0, 0, 0, 0.004) 3px,
      rgba(0, 0, 0, 0.004) 4px
    ),
    /* Fiber texture - vertical lines */
    repeating-linear-gradient(
      0deg,
      transparent,
      transparent 7px,
      rgba(0, 0, 0, 0.003) 7px,
      rgba(0, 0, 0, 0.003) 8px
    ),
    /* Water stain effects */
    radial-gradient(ellipse at 30% 60%, rgba(160, 140, 110, 0.03) 0%, transparent 40%),
    radial-gradient(ellipse at 70% 30%, rgba(140, 120, 90, 0.02) 0%, transparent 35%);
  pointer-events: none;
  z-index: 0;
}

/* --- Scrollbar --- */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--paper-dark); }
::-webkit-scrollbar-thumb { background: var(--ink-light); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--ink-medium); }

/* --- Typography --- */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 600;
  line-height: 1.4;
  color: var(--ink-black);
}

h1 {
  font-size: clamp(2.2rem, 5vw, 3.6rem);
  letter-spacing: 0.08em;
}

h2 {
  font-size: clamp(1.6rem, 3.5vw, 2.4rem);
  letter-spacing: 0.06em;
  position: relative;
  margin-bottom: 1.5rem;
}

h2::after {
  content: '';
  display: block;
  width: 60px;
  height: 2px;
  background: var(--ink-black);
  margin-top: 0.75rem;
  opacity: 0.4;
}

h3 {
  font-size: clamp(1.2rem, 2.5vw, 1.6rem);
  letter-spacing: 0.04em;
}

p {
  margin-bottom: 1.2em;
  text-indent: 2em;
  font-size: 1.05rem;
}

a {
  color: var(--ink-dark);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--seal-red);
}

/* --- Loading Screen --- */
#loading-screen {
  position: fixed;
  top: 0; left: 0; right: 0; bottom: 0;
  background: var(--paper);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  z-index: 9999;
  transition: opacity 0.8s ease, visibility 0.8s ease;
}

#loading-screen.hidden {
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
}

.ink-drop {
  width: 40px;
  height: 60px;
  border-radius: 50%;
  background: var(--ink-black);
  animation: inkDrop 1.5s ease-in-out infinite;
  position: relative;
}

.ink-drop::before {
  content: '';
  position: absolute;
  top: -15px;
  left: 50%;
  transform: translateX(-50%);
  width: 12px;
  height: 20px;
  background: var(--ink-black);
  border-radius: 50%;
  animation: inkRipple 1.5s ease-in-out infinite;
}

@keyframes inkDrop {
  0%, 100% {
    border-radius: 50% 50% 50% 50% / 60% 60% 40% 40%;
    transform: scaleY(1);
  }
  50% {
    border-radius: 50% 50% 50% 50% / 40% 40% 60% 60%;
    transform: scaleY(1.1);
  }
}

@keyframes inkRipple {
  0%, 100% { transform: translateX(-50%) scale(1); opacity: 1; }
  50% { transform: translateX(-50%) scale(1.5); opacity: 0.5; }
}

#loading-screen .loading-text {
  margin-top: 1.5rem;
  font-family: var(--font-heading);
  font-size: 1rem;
  color: var(--ink-medium);
  letter-spacing: 0.3em;
  animation: pulse 1.5s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 0.4; }
  50% { opacity: 1; }
}

/* --- Navigation --- */
#main-nav {
  position: fixed;
  top: 0;
  left: -300px;
  width: 300px;
  height: 100vh;
  background: var(--paper-light);
  border-right: 1px solid rgba(0,0,0,0.08);
  z-index: 1000;
  transition: left var(--transition-slow);
  overflow-y: auto;
  box-shadow: 2px 0 30px rgba(0,0,0,0.1);
}

#main-nav.open {
  left: 0;
}

.nav-header {
  padding: 2rem 1.5rem 1rem;
  border-bottom: 1px solid var(--paper-dark);
  text-align: center;
}

.nav-header h2 {
  font-size: 1.3rem;
  margin-bottom: 0;
  letter-spacing: 0.3em;
}

.nav-header h2::after {
  display: none;
}

.nav-header .subtitle {
  font-size: 0.8rem;
  color: var(--ink-light);
  letter-spacing: 0.15em;
  margin-top: 0.3rem;
}

.nav-seal {
  display: inline-block;
  width: 50px;
  height: 50px;
  border: 2px solid var(--seal-red);
  color: var(--seal-red);
  font-family: var(--font-accent);
  font-size: 1.8rem;
  line-height: 50px;
  text-align: center;
  margin-bottom: 0.8rem;
  transform: rotate(-3deg);
  border-radius: 4px;
}

.nav-list {
  list-style: none;
  padding: 0.8rem 0;
}

.nav-list li {
  border-bottom: 1px solid rgba(0,0,0,0.04);
}

.nav-list a {
  display: flex;
  align-items: center;
  padding: 0.85rem 1.5rem;
  font-family: var(--font-heading);
  font-size: 0.95rem;
  color: var(--ink-dark);
  transition: all var(--transition-medium);
  position: relative;
  letter-spacing: 0.05em;
}

.nav-list a::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 3px;
  background: var(--seal-red);
  transform: scaleY(0);
  transition: transform var(--transition-medium);
}

.nav-list a:hover {
  background: var(--ink-faint);
  padding-left: 1.8rem;
}

.nav-list a:hover::before,
.nav-list a.active::before {
  transform: scaleY(1);
}

.nav-list a.active {
  background: rgba(194, 59, 34, 0.05);
  color: var(--seal-red);
}

.nav-list .nav-era {
  font-size: 0.7rem;
  color: var(--ink-light);
  margin-left: 0.5rem;
  font-family: var(--font-body);
}

/* Navigation Toggle Button */
#nav-toggle {
  position: fixed;
  top: 1.2rem;
  left: 1.2rem;
  width: 44px;
  height: 44px;
  background: var(--paper-light);
  border: 1px solid rgba(0,0,0,0.1);
  border-radius: 50%;
  cursor: pointer;
  z-index: 1001;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
  transition: all var(--transition-medium);
  box-shadow: var(--shadow-ink);
}

#nav-toggle:hover {
  background: var(--paper-dark);
  box-shadow: var(--shadow-ink-lg);
}

#nav-toggle span {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--ink-dark);
  transition: all var(--transition-medium);
  transform-origin: center;
}

#nav-toggle.open span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

#nav-toggle.open span:nth-child(2) {
  opacity: 0;
  transform: scaleX(0);
}

#nav-toggle.open span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* Navigation overlay */
#nav-overlay {
  position: fixed;
  top: 0; left: 0; right: 0; bottom: 0;
  background: rgba(0,0,0,0.3);
  z-index: 999;
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-medium);
}

#nav-overlay.open {
  opacity: 1;
  visibility: visible;
}

/* --- Main Content Area --- */
#main-content {
  position: relative;
  z-index: 1;
  min-height: 100vh;
  transition: transform var(--transition-slow);
}

#main-content.shifted {
  transform: translateX(300px);
}

/* --- Page Sections --- */
.page-section {
  display: none;
  opacity: 0;
  animation: pageEnter 0.8s ease forwards;
}

.page-section.active {
  display: block;
  opacity: 1;
}

@keyframes pageEnter {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* --- Hero Section (for each page) --- */
.hero {
  position: relative;
  min-height: 50vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 6rem 2rem 4rem;
  overflow: hidden;
  background: linear-gradient(180deg, #f7f3ea 0%, #f0ead9 100%);
  transition: background 0.3s ease;
}

/* Mouse-reactive ink bloom on hero */
.hero::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0; bottom: 0;
  background: radial-gradient(
    600px circle at var(--ink-x, 50%) var(--ink-y, 50%),
    rgba(0, 0, 0, 0.02) 0%,
    transparent 60%
  );
  opacity: 0;
  transition: opacity 0.6s ease;
  pointer-events: none;
  z-index: 1;
}

.hero:hover::before {
  opacity: 1;
}

.hero-home {
  min-height: 100vh;
}

.hero-ink {
  position: absolute;
  top: 0; left: 0; right: 0; bottom: 0;
  pointer-events: none;
  z-index: 0;
}

.hero-ink svg {
  width: 100%;
  height: 100%;
  opacity: 0.08;
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 800px;
}

.hero-title {
  font-size: clamp(2.5rem, 6vw, 4.5rem);
  letter-spacing: 0.15em;
  margin-bottom: 0.5rem;
  position: relative;
  display: inline-block;
}

.hero-subtitle {
  font-family: var(--font-heading);
  font-size: clamp(1rem, 2vw, 1.3rem);
  color: var(--ink-medium);
  letter-spacing: 0.3em;
  margin-top: 0.5rem;
  font-weight: 300;
}

.hero-era {
  display: inline-block;
  font-size: 0.85rem;
  color: var(--ink-light);
  letter-spacing: 0.2em;
  padding: 0.3rem 1.5rem;
  border: 1px solid rgba(0,0,0,0.15);
  border-radius: 2px;
  margin-top: 1rem;
}

.hero-char {
  font-size: clamp(6rem, 15vw, 12rem);
  font-family: var(--font-glyph);
  color: rgba(0,0,0,0.04);
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  pointer-events: none;
  z-index: 0;
  user-select: none;
  white-space: nowrap;
}

/* Scroll indicator (home) */
.scroll-indicator {
  position: absolute;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  color: var(--ink-light);
  font-size: 0.75rem;
  letter-spacing: 0.2em;
  animation: bounce 2s ease-in-out infinite;
  cursor: pointer;
}

.scroll-indicator .line {
  width: 1px;
  height: 40px;
  background: linear-gradient(to bottom, var(--ink-light), transparent);
}

@keyframes bounce {
  0%, 100% { transform: translateX(-50%) translateY(0); }
  50% { transform: translateX(-50%) translateY(8px); }
}

/* --- Content Container --- */
.content-container {
  max-width: 800px;
  margin: 0 auto;
  padding: 3rem 2rem;
  position: relative;
}

/* --- Ink divider --- */
.ink-divider {
  text-align: center;
  padding: 2rem 0;
  position: relative;
}

.ink-divider::before {
  content: '';
  display: block;
  width: 80%;
  max-width: 300px;
  height: 1px;
  background: linear-gradient(to right, transparent, var(--ink-light), transparent);
  margin: 0 auto;
}

.ink-divider .seal {
  display: inline-block;
  width: 44px;
  height: 44px;
  line-height: 44px;
  text-align: center;
  border: 2px solid var(--seal-red);
  color: var(--seal-red);
  font-family: var(--font-accent);
  font-size: 1rem;
  transform: rotate(-2deg);
  margin: 0.5rem auto;
  opacity: 0.7;
  border-radius: 4px;
  position: relative;
  transition: transform 0.3s ease;
}

.ink-divider .seal:hover {
  transform: rotate(0deg) scale(1.1);
  opacity: 0.9;
}

/* Yin/Yang seal variations */
.seal-yin {
  border: 2px solid var(--seal-red);
  color: var(--seal-red);
  background: transparent;
}

.seal-yang {
  border: 2px solid var(--seal-red);
  color: var(--paper);
  background: var(--seal-red);
}

/* --- Character Evolution Cards --- */
.char-evolution {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
  gap: 1rem;
  margin: 2rem 0;
  padding: 1.5rem;
  background: rgba(255,255,255,0.5);
  border-radius: 4px;
  border: 1px solid rgba(0,0,0,0.06);
}

.char-stage {
  text-align: center;
  padding: 0.8rem;
}

.char-stage .char-glyph {
  font-size: 2.5rem;
  font-family: var(--font-glyph);
  display: block;
  margin-bottom: 0.3rem;
  transition: transform var(--transition-medium);
  cursor: default;
}

.char-stage:hover .char-glyph {
  transform: scale(1.3);
  color: var(--seal-red);
}

.char-stage .char-label {
  font-size: 0.75rem;
  color: var(--ink-light);
  letter-spacing: 0.05em;
}

.char-evolution-title {
  grid-column: 1 / -1;
  font-family: var(--font-heading);
  font-size: 1rem;
  text-align: center;
  color: var(--ink-medium);
  letter-spacing: 0.1em;
  margin-bottom: 0.5rem;
}

/* --- Timeline (Home) --- */
.timeline {
  position: relative;
  padding: 2rem 0;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 50%;
  top: 0;
  bottom: 0;
  width: 2px;
  background: linear-gradient(to bottom, transparent, var(--ink-light), var(--ink-dark), var(--ink-light), transparent);
  transform: translateX(-50%);
}

.timeline-item {
  display: flex;
  align-items: flex-start;
  margin-bottom: 3rem;
  position: relative;
  opacity: 0;
  transform: translateY(30px);
  transition: all 0.8s cubic-bezier(0.22, 1, 0.36, 1);
}

.timeline-item.visible {
  opacity: 1;
  transform: translateY(0);
}

.timeline-item:nth-child(odd) {
  flex-direction: row-reverse;
}

.timeline-content {
  width: calc(50% - 3rem);
  padding: 1.5rem;
  background: var(--paper-light);
  border: 1px solid rgba(0,0,0,0.06);
  border-radius: 4px;
  transition: all var(--transition-medium);
  cursor: pointer;
  position: relative;
}

.timeline-content:hover {
  border-color: var(--ink-light);
  box-shadow: var(--shadow-ink);
  transform: translateY(-2px);
}

.timeline-content h3 {
  font-size: 1.1rem;
  margin-bottom: 0.3rem;
  letter-spacing: 0.1em;
}

.timeline-content .era {
  font-size: 0.8rem;
  color: var(--ink-light);
  font-family: var(--font-heading);
}

.timeline-content p {
  font-size: 0.9rem;
  text-indent: 0;
  margin-top: 0.5rem;
  color: var(--ink-medium);
}

.timeline-dot {
  position: absolute;
  left: 50%;
  top: 1.5rem;
  width: 14px;
  height: 14px;
  background: var(--ink-dark);
  border: 3px solid var(--paper);
  border-radius: 50%;
  transform: translateX(-50%);
  z-index: 1;
  transition: all var(--transition-medium);
}

.timeline-item:hover .timeline-dot {
  background: var(--seal-red);
  transform: translateX(-50%) scale(1.3);
}

.timeline-char {
  position: absolute;
  top: -0.5rem;
  right: -0.5rem;
  font-size: 3rem;
  font-family: var(--font-heading);
  color: rgba(0,0,0,0.04);
  pointer-events: none;
}

/* --- Image Gallery for Calligraphy --- */
.calligraphy-gallery {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1.5rem;
  margin: 2rem 0;
}

.gallery-item {
  text-align: center;
  padding: 1rem;
  background: var(--paper-light);
  border: 1px solid rgba(0,0,0,0.06);
  border-radius: 4px;
  transition: all var(--transition-medium);
}

.gallery-item:hover {
  box-shadow: var(--shadow-ink);
  transform: translateY(-3px);
}

.gallery-item .placeholder-img {
  width: 100%;
  aspect-ratio: 4/3;
  background: linear-gradient(135deg, var(--paper-dark), var(--paper));
  border: 1px solid rgba(0,0,0,0.08);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-heading);
  font-size: 1.2rem;
  color: var(--ink-light);
  letter-spacing: 0.1em;
  margin-bottom: 0.8rem;
  position: relative;
  overflow: hidden;
}

.gallery-item .placeholder-img::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0; bottom: 0;
  background: radial-gradient(ellipse at center, rgba(0,0,0,0.02), transparent);
}

.gallery-item figcaption {
  font-size: 0.85rem;
  color: var(--ink-medium);
  font-family: var(--font-heading);
  letter-spacing: 0.05em;
}

/* --- Quote / Highlight Box --- */
.insight-box {
  margin: 2rem 0;
  padding: 1.5rem 2rem;
  background: linear-gradient(135deg, rgba(194, 59, 34, 0.04), rgba(0,0,0,0.02));
  border-left: 3px solid var(--seal-red);
  border-radius: 0 4px 4px 0;
  font-family: var(--font-heading);
  font-style: italic;
  color: var(--ink-dark);
  position: relative;
}

.insight-box::before {
  content: '"';
  font-size: 3rem;
  color: var(--seal-red);
  opacity: 0.2;
  position: absolute;
  top: -0.2rem;
  left: 0.5rem;
  font-family: serif;
  line-height: 1;
}

/* --- Timeline Interactive Summary Page --- */
.timeline-summary {
  position: relative;
  padding: 4rem 0;
}

.evolution-bar {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  margin: 2rem 0;
}

.evolution-row {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 0.5rem 1rem;
  background: rgba(255,255,255,0.4);
  border-radius: 4px;
  transition: all var(--transition-medium);
  cursor: pointer;
}

.evolution-row:hover {
  background: rgba(255,255,255,0.8);
  transform: translateX(5px);
  box-shadow: var(--shadow-ink);
}

.evolution-row .era-label {
  min-width: 80px;
  font-size: 0.8rem;
  color: var(--ink-light);
  font-family: var(--font-heading);
}

.evolution-row .evolved-char {
  flex: 1;
  display: flex;
  gap: 0.5rem;
  align-items: center;
}

.evolution-row .evolved-char span {
  font-size: 1.6rem;
  font-family: var(--font-heading);
  padding: 0.2rem 0.5rem;
  transition: all var(--transition-fast);
}

.evolution-row .evolved-char span:hover {
  color: var(--seal-red);
  transform: scale(1.4);
}

.evolution-row .arrow {
  color: var(--ink-light);
  font-size: 1.2rem;
}

/* --- Footer --- */
.site-footer {
  text-align: center;
  padding: 3rem 2rem;
  border-top: 1px solid rgba(0,0,0,0.06);
  color: var(--ink-light);
  font-size: 0.85rem;
  font-family: var(--font-heading);
  letter-spacing: 0.1em;
  position: relative;
}

.site-footer .footer-seal {
  font-size: 2rem;
  color: var(--seal-red);
  opacity: 0.5;
  display: block;
  margin-bottom: 0.5rem;
  transform: rotate(-3deg);
}

/* --- Brush-stroke decorative elements --- */
.brush-stroke {
  height: 4px;
  width: 100%;
  max-width: 120px;
  margin: 1rem auto;
  background: linear-gradient(to right, transparent, var(--ink-dark), transparent);
  border-radius: 2px;
  opacity: 0.3;
}

/* --- Animations --- */
.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: all 0.8s cubic-bezier(0.22, 1, 0.36, 1);
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Ink splash effect on click - organic */
.ink-splash {
  position: fixed;
  pointer-events: none;
  z-index: 9998;
  background: radial-gradient(circle, rgba(0,0,0,0.04) 0%, transparent 70%);
  animation: inkSplashOrganic 1.2s ease-out forwards;
  border-radius: 60% 40% 50% 50% / 50% 55% 45% 55%;
}

@keyframes inkSplashOrganic {
  0% {
    width: 0;
    height: 0;
    opacity: 1;
    border-radius: 60% 40% 50% 50% / 50% 55% 45% 55%;
  }
  50% {
    opacity: 0.5;
    border-radius: 40% 60% 45% 55% / 55% 45% 60% 40%;
  }
  100% {
    width: 200px;
    height: 200px;
    opacity: 0;
    border-radius: 50% 50% 50% 50% / 50% 50% 50% 50%;
    transform: translate(-100px, -100px);
  }
}

/* Ink particle effect */
.ink-particle {
  position: fixed;
  pointer-events: none;
  border-radius: 50%;
  background: rgba(0,0,0,0.04);
  animation: floatUp 8s ease-out infinite;
}

@keyframes floatUp {
  0% {
    transform: translateY(100vh) scale(0);
    opacity: 0;
  }
  20% {
    opacity: 1;
  }
  80% {
    opacity: 0.3;
  }
  100% {
    transform: translateY(-10vh) scale(1);
    opacity: 0;
  }
}

/* Scroll-triggered ink wash reveal */
.ink-reveal {
  position: relative;
  overflow: hidden;
}

.ink-reveal::after {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0; bottom: 0;
  background: var(--paper);
  transform: translateX(0);
  transition: transform 1.2s cubic-bezier(0.22, 1, 0.36, 1);
}

.ink-reveal.revealed::after {
  transform: translateX(100%);
}

/* Rice paper texture enhancement - fiber feel overlay */
body::after {
  content: '';
  position: fixed;
  top: 0; left: 0; right: 0; bottom: 0;
  background-image: 
    repeating-linear-gradient(
      0deg,
      transparent,
      transparent 1px,
      rgba(139, 119, 90, 0.002) 1px,
      rgba(139, 119, 90, 0.002) 3px
    );
  pointer-events: none;
  z-index: 1;
  opacity: 0.6;
}

/* --- Responsive --- */
@media (max-width: 768px) {
  #main-nav {
    width: 260px;
    left: -260px;
  }

  #main-content.shifted {
    transform: translateX(260px);
  }

  .timeline::before {
    left: 30px;
  }

  .timeline-item {
    flex-direction: row !important;
  }

  .timeline-content {
    width: calc(100% - 60px);
    margin-left: 60px;
  }

  .timeline-dot {
    left: 30px;
  }

  .char-evolution {
    grid-template-columns: repeat(3, 1fr);
  }

  .hero {
    min-height: 40vh;
    padding: 5rem 1.5rem 3rem;
  }

  .content-container {
    padding: 2rem 1.2rem;
  }

  .evolution-row {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.3rem;
  }

  .evolution-row .era-label {
    min-width: auto;
  }
}

@media (max-width: 480px) {
  .char-evolution {
    grid-template-columns: repeat(2, 1fr);
  }

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

/* --- Print-friendly --- */
@media print {
  #main-nav, #nav-toggle, #nav-overlay {
    display: none !important;
  }

  .hero {
    min-height: auto;
    padding: 2rem;
  }

  .page-section {
    display: block !important;
    opacity: 1 !important;
    page-break-after: always;
  }
}

/* Ink wash canvas for dynamic art */
#ink-canvas {
  position: fixed;
  top: 0; left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 0;
  opacity: 0.06;
}