/* ============================================
   SANYA — Ink-Wash Mountain Aesthetic
   Black · Gold · Ash Theme
   ============================================ */

/* ---------- CSS Custom Properties ---------- */
:root {
  /* Ink-black base palette */
  --ink-deep: #0a0a0a;
  --ink-primary: #141414;
  --ink-medium: #1c1c1c;
  --ink-light: #2a2a2a;
  --ink-faint: #3a3a3a;

  /* Ash / gray tones */
  --ash-dark: #4a4a4a;
  --ash-medium: #6a6a6a;
  --ash-light: #8a8a8a;
  --ash-pale: #b0b0b0;

  /* Gold accents */
  --gold-deep: #8b6914;
  --gold-primary: #c9a84c;
  --gold-light: #d4b86a;
  --gold-pale: #e8d4a0;
  --gold-glow: rgba(201, 168, 76, 0.15);

  /* Mist / cloud tones */
  --mist-white: #e8e4dc;
  --mist-light: #d0ccc4;
  --mist-medium: #a8a49c;
  --mist-dark: #78746c;

  /* Paper & background */
  --paper-white: #0e0e0e;
  --paper-cream: #161616;
  --paper-warm: #1e1e1e;
  --paper-aged: #252525;

  /* Text colors */
  --text-primary: #e0dcd4;
  --text-secondary: #a8a49c;
  --text-muted: #706c64;
  --text-faint: #504c44;

  /* Functional */
  --border-light: rgba(201, 168, 76, 0.08);
  --border-medium: rgba(201, 168, 76, 0.15);
  --border-subtle: rgba(255, 255, 255, 0.06);
  --shadow-soft: 0 2px 20px rgba(0, 0, 0, 0.5);
  --shadow-hover: 0 4px 30px rgba(0, 0, 0, 0.6);
  --shadow-gold: 0 0 30px rgba(201, 168, 76, 0.08);

  /* Typography */
  --font-serif: 'Noto Serif SC', 'Source Han Serif SC', 'STSong', Georgia, serif;
  --font-sans: 'Noto Sans SC', 'Source Han Sans SC', 'PingFang SC', system-ui, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  --space-4xl: 6rem;

  /* Layout */
  --max-width: 1100px;
  --nav-height: 64px;

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 400ms ease;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-sans);
  color: var(--text-primary);
  background-color: var(--ink-deep);
  line-height: 1.7;
  min-height: 100vh;
  overflow-x: hidden;
}

/* Ink texture overlay */
body::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 9999;
  background-image:
    url("data:image/svg+xml,%3Csvg viewBox='0 0 512 512' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noise'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.65' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noise)' opacity='0.04'/%3E%3C/svg%3E");
  opacity: 0.5;
}

/* ---------- Typography ---------- */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-serif);
  font-weight: 600;
  line-height: 1.3;
  color: var(--text-primary);
}

h1 { font-size: clamp(2rem, 5vw, 3.2rem); letter-spacing: 0.02em; }
h2 { font-size: clamp(1.5rem, 3.5vw, 2.2rem); letter-spacing: 0.01em; }
h3 { font-size: clamp(1.1rem, 2.5vw, 1.4rem); }

p {
  margin-bottom: var(--space-md);
  color: var(--text-secondary);
}

a {
  color: var(--gold-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--gold-light);
}

.cn-text {
  font-family: var(--font-serif);
  letter-spacing: 0.05em;
}

/* ---------- Layout ---------- */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-xl);
}

section {
  padding: var(--space-4xl) 0;
}

/* ---------- Navigation ---------- */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background: rgba(10, 10, 10, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-subtle);
  z-index: 1000;
  transition: all var(--transition-base);
}

.nav.scrolled {
  box-shadow: var(--shadow-soft);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-xl);
}

.nav-logo {
  font-family: var(--font-serif);
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: 0.05em;
}

.nav-logo:hover {
  color: var(--gold-primary);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
  list-style: none;
}

.nav-links a {
  font-size: 0.9rem;
  color: var(--text-muted);
  letter-spacing: 0.03em;
  padding: var(--space-xs) 0;
  position: relative;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 1px;
  background: var(--gold-primary);
  transition: width var(--transition-base);
}

.nav-links a:hover {
  color: var(--text-primary);
}

.nav-links a:hover::after,
.nav-links a.active::after {
  width: 100%;
}

.nav-links a.active {
  color: var(--text-primary);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-sm);
}

.nav-toggle span {
  display: block;
  width: 22px;
  height: 1.5px;
  background: var(--text-primary);
  transition: all var(--transition-base);
}

/* ---------- Hero Section ---------- */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding-top: var(--nav-height);
  position: relative;
  overflow: hidden;
}

/* Ink-wash mountain atmosphere */
.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background:
    radial-gradient(ellipse at 20% 80%, rgba(201, 168, 76, 0.04) 0%, transparent 50%),
    radial-gradient(ellipse at 80% 20%, rgba(201, 168, 76, 0.03) 0%, transparent 50%),
    radial-gradient(ellipse at 50% 50%, rgba(40, 40, 40, 0.5) 0%, transparent 70%);
  pointer-events: none;
}

.hero::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 200px;
  background: linear-gradient(to top, var(--ink-deep), transparent);
  pointer-events: none;
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 700px;
}

.hero-title {
  font-size: clamp(3rem, 8vw, 5.5rem);
  font-weight: 300;
  letter-spacing: 0.15em;
  color: var(--text-primary);
  margin-bottom: var(--space-md);
  font-family: var(--font-serif);
  text-shadow: 0 0 60px rgba(201, 168, 76, 0.1);
}

.hero-subtitle {
  font-size: clamp(0.85rem, 2vw, 1rem);
  color: var(--text-muted);
  letter-spacing: 0.25em;
  text-transform: uppercase;
  margin-bottom: var(--space-2xl);
  font-weight: 400;
}

.hero-intro {
  font-size: 1.05rem;
  color: var(--text-secondary);
  line-height: 1.8;
  margin-bottom: var(--space-xl);
  max-width: 550px;
  margin-left: auto;
  margin-right: auto;
}

.hero-motto {
  font-family: var(--font-serif);
  font-size: 1.2rem;
  color: var(--gold-primary);
  letter-spacing: 0.2em;
  margin-bottom: var(--space-3xl);
  text-shadow: 0 0 40px rgba(201, 168, 76, 0.2);
}

.hero-divider {
  width: 80px;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--gold-primary), transparent);
  margin: 0 auto var(--space-3xl);
  opacity: 0.6;
}

.hero-buttons {
  display: flex;
  gap: var(--space-md);
  justify-content: center;
  flex-wrap: wrap;
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: 0.75rem 1.8rem;
  font-family: var(--font-sans);
  font-size: 0.88rem;
  letter-spacing: 0.05em;
  border: 1px solid var(--border-medium);
  border-radius: 2px;
  background: transparent;
  color: var(--gold-primary);
  cursor: pointer;
  transition: all var(--transition-base);
  text-decoration: none;
}

.btn:hover {
  background: var(--gold-primary);
  color: var(--ink-deep);
  border-color: var(--gold-primary);
  box-shadow: var(--shadow-gold);
}

.btn-primary {
  background: var(--gold-primary);
  color: var(--ink-deep);
  border-color: var(--gold-primary);
}

.btn-primary:hover {
  background: var(--gold-light);
  border-color: var(--gold-light);
  box-shadow: 0 0 30px rgba(201, 168, 76, 0.2);
}

/* ---------- Section Headers ---------- */
.section-header {
  text-align: center;
  margin-bottom: var(--space-3xl);
}

.section-header h2 {
  margin-bottom: var(--space-sm);
}

.section-header .cn-subtitle {
  font-family: var(--font-serif);
  font-size: 0.95rem;
  color: var(--text-muted);
  letter-spacing: 0.1em;
}

.section-divider {
  width: 40px;
  height: 1px;
  background: var(--gold-primary);
  margin: var(--space-lg) auto;
  opacity: 0.4;
}

/* ---------- About Section ---------- */
.about {
  background: linear-gradient(180deg, var(--ink-deep) 0%, var(--ink-primary) 100%);
}

.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-3xl);
  align-items: start;
}

.about-card {
  background: var(--ink-medium);
  border: 1px solid var(--border-subtle);
  padding: var(--space-2xl);
  position: relative;
}

.about-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 2px;
  height: 100%;
  background: linear-gradient(180deg, var(--gold-primary), transparent);
  opacity: 0.5;
}

.about-card h3 {
  font-size: 1.1rem;
  margin-bottom: var(--space-lg);
  color: var(--gold-primary);
}

.about-card p {
  font-size: 0.95rem;
  line-height: 1.9;
}

.about-card .cn-text {
  font-size: 0.92rem;
  line-height: 2;
  color: var(--text-muted);
}

/* ---------- Focus Areas ---------- */
.focus-areas {
  background: var(--ink-deep);
}

.focus-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: var(--space-lg);
}

.focus-card {
  background: var(--ink-medium);
  border: 1px solid var(--border-subtle);
  padding: var(--space-xl);
  transition: all var(--transition-base);
  position: relative;
  overflow: hidden;
}

.focus-card::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 2px;
  background: linear-gradient(90deg, var(--gold-primary), transparent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition-base);
}

.focus-card:hover {
  box-shadow: var(--shadow-hover), var(--shadow-gold);
  transform: translateY(-2px);
  border-color: var(--border-medium);
}

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

.focus-card-icon {
  font-size: 1.5rem;
  margin-bottom: var(--space-md);
  color: var(--gold-primary);
  opacity: 0.7;
}

.focus-card h3 {
  font-size: 1rem;
  margin-bottom: var(--space-sm);
  font-weight: 500;
}

.focus-card p {
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 1.6;
}

/* ---------- Projects Section ---------- */
.projects {
  background: linear-gradient(180deg, var(--ink-primary) 0%, var(--ink-deep) 100%);
}

.project-list {
  display: grid;
  gap: var(--space-lg);
}

.project-card {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: var(--space-xl);
  align-items: center;
  background: var(--ink-medium);
  border: 1px solid var(--border-subtle);
  padding: var(--space-xl) var(--space-2xl);
  transition: all var(--transition-base);
}

.project-card:hover {
  box-shadow: var(--shadow-hover), var(--shadow-gold);
  border-color: var(--border-medium);
}

.project-info h3 {
  font-size: 1.1rem;
  margin-bottom: var(--space-xs);
}

.project-info p {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-bottom: 0;
}

.project-tags {
  display: flex;
  gap: var(--space-sm);
  flex-wrap: wrap;
}

.tag {
  font-size: 0.75rem;
  padding: 0.25rem 0.75rem;
  background: var(--ink-light);
  border: 1px solid var(--border-subtle);
  color: var(--text-muted);
  letter-spacing: 0.03em;
}

/* ---------- Articles Section ---------- */
.articles {
  background: var(--ink-deep);
}

.article-list {
  display: grid;
  gap: var(--space-lg);
}

.article-card {
  display: block;
  background: var(--ink-medium);
  border: 1px solid var(--border-subtle);
  padding: var(--space-xl) var(--space-2xl);
  transition: all var(--transition-base);
  text-decoration: none;
}

.article-card:hover {
  box-shadow: var(--shadow-hover), var(--shadow-gold);
  transform: translateY(-1px);
  border-color: var(--border-medium);
}

.article-meta {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  margin-bottom: var(--space-sm);
  font-size: 0.8rem;
  color: var(--text-muted);
}

.article-meta .date {
  letter-spacing: 0.05em;
}

.article-card h3 {
  font-size: 1.15rem;
  margin-bottom: var(--space-sm);
  transition: color var(--transition-fast);
}

.article-card:hover h3 {
  color: var(--gold-light);
}

.article-card .summary {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: var(--space-md);
}

.article-tags {
  display: flex;
  gap: var(--space-sm);
  flex-wrap: wrap;
}

.read-more {
  font-size: 0.85rem;
  color: var(--gold-primary);
  letter-spacing: 0.05em;
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  margin-top: var(--space-sm);
}

.read-more::after {
  content: '→';
  transition: transform var(--transition-fast);
}

.article-card:hover .read-more::after {
  transform: translateX(4px);
}

/* ---------- Article Page ---------- */
.article-page {
  padding-top: calc(var(--nav-height) + var(--space-3xl));
}

.article-header {
  text-align: center;
  margin-bottom: var(--space-3xl);
  padding-bottom: var(--space-2xl);
  border-bottom: 1px solid var(--border-subtle);
}

.article-header h1 {
  margin-bottom: var(--space-md);
}

.article-content {
  max-width: 720px;
  margin: 0 auto;
  padding-bottom: var(--space-4xl);
}

.article-content h2 {
  margin-top: var(--space-3xl);
  margin-bottom: var(--space-lg);
}

.article-content h3 {
  margin-top: var(--space-2xl);
  margin-bottom: var(--space-md);
}

.article-content p {
  margin-bottom: var(--space-lg);
  font-size: 1rem;
  line-height: 1.9;
}

.article-content code {
  font-family: var(--font-mono);
  font-size: 0.88em;
  background: var(--ink-light);
  padding: 0.15em 0.4em;
  border: 1px solid var(--border-subtle);
  color: var(--gold-primary);
}

.article-content pre {
  background: var(--ink-primary);
  color: var(--gold-pale);
  padding: var(--space-xl);
  overflow-x: auto;
  margin: var(--space-xl) 0;
  border: 1px solid var(--border-subtle);
}

.article-content pre code {
  background: none;
  border: none;
  padding: 0;
  color: inherit;
}

.article-content blockquote {
  border-left: 2px solid var(--gold-primary);
  padding-left: var(--space-lg);
  margin: var(--space-xl) 0;
  color: var(--text-muted);
  font-style: italic;
}

.article-content ul, .article-content ol {
  margin: var(--space-lg) 0;
  padding-left: var(--space-xl);
}

.article-content li {
  margin-bottom: var(--space-sm);
  line-height: 1.8;
}

/* ---------- Contact Section ---------- */
.contact {
  background: linear-gradient(180deg, var(--ink-deep) 0%, var(--ink-primary) 100%);
  text-align: center;
}

.contact-links {
  display: flex;
  justify-content: center;
  gap: var(--space-xl);
  margin-top: var(--space-2xl);
  flex-wrap: wrap;
}

.contact-link {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-xl);
  border: 1px solid var(--border-subtle);
  background: var(--ink-medium);
  min-width: 140px;
  transition: all var(--transition-base);
  text-decoration: none;
}

.contact-link:hover {
  box-shadow: var(--shadow-hover), var(--shadow-gold);
  border-color: var(--gold-primary);
}

.contact-link-icon {
  font-size: 1.5rem;
  color: var(--gold-primary);
  opacity: 0.7;
}

.contact-link-label {
  font-size: 0.85rem;
  color: var(--text-secondary);
  letter-spacing: 0.05em;
}

/* ---------- Footer ---------- */
.footer {
  padding: var(--space-2xl) 0;
  border-top: 1px solid var(--border-subtle);
  text-align: center;
  background: var(--ink-deep);
}

.footer p {
  font-size: 0.8rem;
  color: var(--text-muted);
  letter-spacing: 0.05em;
  margin-bottom: var(--space-sm);
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: var(--space-lg);
}

.footer-links a {
  font-size: 0.8rem;
  color: var(--text-muted);
}

.footer-links a:hover {
  color: var(--gold-primary);
}

/* ---------- Ink Wash Decorative Elements ---------- */
.ink-dot {
  display: inline-block;
  width: 4px;
  height: 4px;
  background: var(--gold-primary);
  border-radius: 50%;
  margin: 0 var(--space-sm);
  vertical-align: middle;
  opacity: 0.5;
}

.garden-line {
  width: 100%;
  height: 1px;
  background: repeating-linear-gradient(
    90deg,
    var(--border-subtle) 0px,
    var(--border-subtle) 8px,
    transparent 8px,
    transparent 16px
  );
  margin: var(--space-3xl) 0;
}

/* ---------- Responsive Design ---------- */
@media (max-width: 768px) {
  :root {
    --nav-height: 56px;
  }

  .container {
    padding: 0 var(--space-lg);
  }

  section {
    padding: var(--space-3xl) 0;
  }

  .nav-toggle {
    display: flex;
  }

  .nav-links {
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(10, 10, 10, 0.98);
    backdrop-filter: blur(12px);
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: var(--space-xl);
    transform: translateX(100%);
    transition: transform var(--transition-base);
  }

  .nav-links.active {
    transform: translateX(0);
  }

  .nav-links a {
    font-size: 1.1rem;
  }

  .hero-title {
    letter-spacing: 0.08em;
  }

  .hero-buttons {
    flex-direction: column;
    align-items: center;
  }

  .btn {
    width: 100%;
    max-width: 260px;
    justify-content: center;
  }

  .about-grid {
    grid-template-columns: 1fr;
    gap: var(--space-xl);
  }

  .project-card {
    grid-template-columns: 1fr;
    gap: var(--space-md);
  }

  .focus-grid {
    grid-template-columns: 1fr 1fr;
    gap: var(--space-md);
  }

  .contact-links {
    flex-direction: column;
    align-items: center;
  }

  .contact-link {
    width: 100%;
    max-width: 280px;
  }
}

@media (max-width: 480px) {
  .focus-grid {
    grid-template-columns: 1fr;
  }

  .hero-subtitle {
    letter-spacing: 0.1em;
    font-size: 0.78rem;
  }
}

/* ---------- Print Styles ---------- */
@media print {
  .nav, .footer, .hero-buttons {
    display: none;
  }

  body::before {
    display: none;
  }

  .hero {
    min-height: auto;
    padding: 2rem 0;
  }
}

/* ---------- Animations ---------- */
@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.fade-in {
  animation: fadeIn 0.6s ease forwards;
}

.focus-card:nth-child(1) { animation-delay: 0.05s; }
.focus-card:nth-child(2) { animation-delay: 0.1s; }
.focus-card:nth-child(3) { animation-delay: 0.15s; }
.focus-card:nth-child(4) { animation-delay: 0.2s; }
.focus-card:nth-child(5) { animation-delay: 0.25s; }
.focus-card:nth-child(6) { animation-delay: 0.3s; }
.focus-card:nth-child(7) { animation-delay: 0.35s; }
.focus-card:nth-child(8) { animation-delay: 0.4s; }

/* ---------- Utility Classes ---------- */
.text-center { text-align: center; }
.text-muted { color: var(--text-muted); }
.mt-lg { margin-top: var(--space-lg); }
.mt-xl { margin-top: var(--space-xl); }
.mb-lg { margin-bottom: var(--space-lg); }
.mb-xl { margin-bottom: var(--space-xl); }