@import url('https://fonts.googleapis.com/css2?family=Cinzel:wght@400;600;700&family=Plus+Jakarta+Sans:ital,wght@0,300;0,400;0,500;0,600;1,300;1,400&family=Shippori+Mincho:wght@400;500;600;700;800&family=Zen+Old+Mincho:wght@400;700&display=swap');

:root {
  --color-bg: #0e0f0e;
  --color-surface: #151715;
  --color-surface-hover: #1c1f1c;
  --color-surface-card: #181b18;
  --color-surface-elevated: #202420;
  
  --color-paper: #f4efe6;
  --color-paper-muted: #b8b1a4;
  --color-paper-subtle: #7a766e;
  
  --color-charcoal: #111211;
  --color-moss: #2c3831;
  --color-moss-light: #44564b;
  
  --color-vermilion: #b93828;
  --color-vermilion-glow: rgba(185, 56, 40, 0.25);
  
  --color-gold: #c5a059;
  --color-gold-light: #e4c88e;
  --color-gold-glow: rgba(197, 160, 89, 0.2);
  
  --color-border: rgba(244, 239, 230, 0.08);
  --color-border-bright: rgba(244, 239, 230, 0.18);
  
  --font-serif: 'Shippori Mincho', 'Zen Old Mincho', serif;
  --font-display: 'Cinzel', serif;
  --font-sans: 'Plus Jakarta Sans', sans-serif;
  
  --ease-zen: cubic-bezier(0.16, 1, 0.3, 1);
}

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

html {
  scroll-behavior: smooth;
  background-color: var(--color-bg);
  color: var(--color-paper);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  overflow-x: hidden;
  position: relative;
  background-color: var(--color-bg);
  background-image: 
    radial-gradient(circle at 50% 0%, rgba(44, 56, 49, 0.18) 0%, transparent 70%),
    radial-gradient(circle at 100% 50%, rgba(197, 160, 89, 0.04) 0%, transparent 50%),
    radial-gradient(circle at 0% 80%, rgba(185, 56, 40, 0.04) 0%, transparent 60%);
}

/* Authentic Paper Grain Texture Overlay */
body::before {
  content: "";
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 999;
  opacity: 0.035;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noiseFilter'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.8' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noiseFilter)'/%3E%3C/svg%3E");
}

/* Typography Utility */
.font-serif { font-family: var(--font-serif); }
.font-display { font-family: var(--font-display); }
.font-sans { font-family: var(--font-sans); }

.vertical-text {
  writing-mode: vertical-rl;
  text-orientation: upright;
  letter-spacing: 0.3em;
}

/* Custom Japanese Seal / Hanko Stamp */
.hanko-seal {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border: 2px solid var(--color-vermilion);
  color: var(--color-vermilion);
  font-family: var(--font-serif);
  font-weight: 800;
  font-size: 1.1rem;
  border-radius: 4px;
  transform: rotate(-3deg);
  box-shadow: 0 0 16px var(--color-vermilion-glow);
  position: relative;
  user-select: none;
  transition: all 0.4s var(--ease-zen);
}

.hanko-seal::after {
  content: "";
  position: absolute;
  inset: 2px;
  border: 1px dashed rgba(185, 56, 40, 0.4);
  border-radius: 2px;
}

.hanko-seal:hover {
  transform: rotate(0deg) scale(1.05);
  box-shadow: 0 0 24px var(--color-vermilion-glow);
}

/* Gold Leaf Accent */
.gold-shimmer {
  background: linear-gradient(135deg, #d4b373 0%, #f6e6be 40%, #c5a059 70%, #99742a 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  display: inline-block;
}

/* Button & Interactive styles */
.btn-zen {
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
  padding: 0.9rem 2rem;
  background: transparent;
  color: var(--color-paper);
  font-family: var(--font-sans);
  font-size: 0.85rem;
  font-weight: 500;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  border: 1px solid var(--color-border-bright);
  border-radius: 0;
  cursor: pointer;
  overflow: hidden;
  transition: all 0.4s var(--ease-zen);
}

.btn-zen::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: var(--color-paper);
  transition: transform 0.5s var(--ease-zen);
  z-index: 0;
}

.btn-zen:hover {
  color: var(--color-bg);
  border-color: var(--color-paper);
}

.btn-zen:hover::before {
  transform: translateX(100%);
}

.btn-zen > * {
  position: relative;
  z-index: 1;
}

.btn-zen-vermilion {
  background: var(--color-vermilion);
  border-color: var(--color-vermilion);
  color: #fff;
  box-shadow: 0 4px 20px var(--color-vermilion-glow);
}

.btn-zen-vermilion::before {
  background: #96281b;
}

.btn-zen-vermilion:hover {
  color: #fff;
  border-color: #96281b;
  transform: translateY(-2px);
  box-shadow: 0 6px 28px rgba(185, 56, 40, 0.4);
}

/* Header & Nav */
.glass-header {
  background: rgba(14, 15, 14, 0.75);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--color-border);
  transition: all 0.3s ease;
}

.glass-header.scrolled {
  background: rgba(14, 15, 14, 0.92);
  border-bottom-color: rgba(244, 239, 230, 0.12);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
}

/* Course Card / Gallery Items */
.course-nav-item {
  position: relative;
  transition: all 0.3s var(--ease-zen);
  cursor: pointer;
}

.course-nav-item.active {
  color: var(--color-paper);
  background: var(--color-surface-elevated);
  border-left: 2px solid var(--color-vermilion);
}

.course-nav-item.active .course-kanji {
  color: var(--color-gold);
}

/* Image Reveal Mask */
.img-reveal-wrapper {
  position: relative;
  overflow: hidden;
}

.img-reveal-wrapper img {
  transition: transform 0.8s cubic-bezier(0.2, 0.8, 0.2, 1), filter 0.6s ease;
}

.img-reveal-wrapper:hover img {
  transform: scale(1.04);
}

/* Ambience Audio Player Pill */
.audio-pill {
  background: rgba(24, 27, 24, 0.8);
  border: 1px solid var(--color-border-bright);
  backdrop-filter: blur(8px);
  transition: all 0.3s ease;
}

.audio-pill:hover {
  border-color: var(--color-gold);
}

.wave-bar {
  width: 3px;
  background: var(--color-gold);
  border-radius: 2px;
  animation: wave 1.2s ease-in-out infinite alternate;
}

.wave-bar:nth-child(2) { animation-delay: 0.2s; }
.wave-bar:nth-child(3) { animation-delay: 0.4s; }
.wave-bar:nth-child(4) { animation-delay: 0.6s; }

@keyframes wave {
  0% { height: 4px; }
  100% { height: 16px; }
}

.audio-pill.paused .wave-bar {
  animation: none;
  height: 4px;
  background: var(--color-paper-subtle);
}

/* Modal Drawer Backdrop */
.drawer-backdrop {
  background: rgba(8, 9, 8, 0.82);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

/* Custom Scrollbar */
::-webkit-scrollbar {
  width: 6px;
  height: 6px;
}
::-webkit-scrollbar-track {
  background: var(--color-bg);
}
::-webkit-scrollbar-thumb {
  background: var(--color-moss);
  border-radius: 3px;
}
::-webkit-scrollbar-thumb:hover {
  background: var(--color-paper-subtle);
}

/* Floating Seasonal Ribbon */
.season-ribbon {
  background: linear-gradient(180deg, var(--color-moss) 0%, rgba(44, 56, 49, 0.4) 100%);
  border: 1px solid rgba(197, 160, 89, 0.25);
}

/* Animations */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(12px); }
  to { opacity: 1; transform: translateY(0); }
}

.animate-fade-in {
  animation: fadeIn 0.6s var(--ease-zen) forwards;
}

/* Focus styles for A11y */
button:focus-visible, a:focus-visible, input:focus-visible, select:focus-visible {
  outline: 2px solid var(--color-gold);
  outline-offset: 3px;
}