/* ============================================
   PARTs - "Warm Studio" Modern Redesign
   Deep slate + amber/gold accent
   ============================================ */

@import url('https://fonts.googleapis.com/css2?family=DM+Serif+Display:ital@0;1&family=Inter:wght@400;500;600;700&display=swap');

:root {
  --bg-deep: #0f1115;
  --bg-surface: #16181d;
  --bg-card: #1c1f26;
  --bg-card-hover: #22262f;
  --accent: #d4a853;
  --accent-light: #e8c97a;
  --accent-glow: rgba(212, 168, 83, 0.15);
  --accent-glow-strong: rgba(212, 168, 83, 0.25);
  --text-primary: #f0ece4;
  --text-secondary: #9a968e;
  --text-muted: #5c5950;
  --border: rgba(212, 168, 83, 0.1);
  --border-hover: rgba(212, 168, 83, 0.25);
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --font-display: 'DM Serif Display', Georgia, 'Times New Roman', serif;
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, system-ui, sans-serif;
  --max-width: 1100px;
  --ease: cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
}

body {
  font-family: var(--font-body);
  color: var(--text-primary);
  background: var(--bg-deep);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

/* Subtle grain texture */
body::after {
  content: '';
  position: fixed;
  inset: 0;
  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='0.03'/%3E%3C/svg%3E");
  pointer-events: none;
  z-index: 0;
}

/* ---- Navigation ---- */
.nav-wrapper {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  transition: all 0.4s var(--ease);
}

.nav-wrapper.scrolled {
  background: rgba(15, 17, 21, 0.9);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
}

.nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1.25rem 2rem;
}

.nav-brand {
  font-family: var(--font-display);
  font-size: 1.35rem;
  color: var(--accent);
  letter-spacing: 0.01em;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.nav-links a {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.85rem;
  font-weight: 500;
  padding: 0.45rem 0.9rem;
  border-radius: var(--radius-sm);
  transition: all 0.25s var(--ease);
  letter-spacing: 0.02em;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--accent);
  background: var(--accent-glow);
}

.lang-btn {
  background: transparent;
  color: var(--accent);
  border: 1px solid var(--border-hover);
  padding: 0.35rem 0.8rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-weight: 600;
  font-size: 0.75rem;
  font-family: var(--font-body);
  letter-spacing: 0.08em;
  transition: all 0.25s var(--ease);
  margin-left: 0.5rem;
}

.lang-btn:hover {
  background: var(--accent-glow);
}

.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
}

.nav-toggle span {
  display: block;
  width: 20px;
  height: 1.5px;
  background: var(--text-primary);
  margin: 5px 0;
  border-radius: 1px;
  transition: all 0.25s var(--ease);
}

/* ---- Hero ---- */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 8rem 2rem 6rem;
  position: relative;
  z-index: 1;
}

.hero::before {
  content: '';
  position: absolute;
  top: -20%;
  right: -10%;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(212, 168, 83, 0.06) 0%, transparent 70%);
  border-radius: 50%;
  pointer-events: none;
}

.hero-content {
  max-width: 720px;
  text-align: center;
}

.hero-tag {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 1.75rem;
  position: relative;
}

.hero-tag::before,
.hero-tag::after {
  content: '';
  position: absolute;
  top: 50%;
  width: 30px;
  height: 1px;
  background: var(--accent);
  opacity: 0.4;
}

.hero-tag::before { right: calc(100% + 12px); }
.hero-tag::after { left: calc(100% + 12px); }

.hero h1 {
  font-family: var(--font-display);
  font-size: clamp(2.8rem, 6vw, 4.2rem);
  font-weight: 400;
  line-height: 1.15;
  letter-spacing: -0.01em;
  margin-bottom: 1.5rem;
  color: var(--text-primary);
}

.hero h1 em {
  color: var(--accent);
  font-style: italic;
}

.hero-desc {
  font-size: 1.05rem;
  color: var(--text-secondary);
  max-width: 520px;
  margin: 0 auto 2.5rem;
  line-height: 1.75;
}

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

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.8rem 1.8rem;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 0.9rem;
  font-family: var(--font-body);
  cursor: pointer;
  text-decoration: none;
  transition: all 0.25s var(--ease);
  border: none;
}

.btn-gold {
  background: var(--accent);
  color: var(--bg-deep);
  box-shadow: 0 0 24px var(--accent-glow);
}

.btn-gold:hover {
  background: var(--accent-light);
  transform: translateY(-2px);
  box-shadow: 0 4px 32px var(--accent-glow-strong);
}

.btn-outline {
  background: transparent;
  color: var(--text-primary);
  border: 1px solid var(--border-hover);
}

.btn-outline:hover {
  background: var(--accent-glow);
  border-color: var(--accent);
}

.btn svg {
  width: 15px;
  height: 15px;
}

/* ---- Sections ---- */
.section {
  padding: 6rem 2rem;
  position: relative;
  z-index: 1;
}

.section-inner {
  max-width: var(--max-width);
  margin: 0 auto;
}

.section-header {
  margin-bottom: 3.5rem;
}

.section-header.centered {
  text-align: center;
}

.section-tag {
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 0.75rem;
  display: block;
}

.section-title {
  font-family: var(--font-display);
  font-size: clamp(1.8rem, 3.5vw, 2.6rem);
  font-weight: 400;
  line-height: 1.2;
  color: var(--text-primary);
  margin-bottom: 0.75rem;
}

.section-desc {
  font-size: 0.95rem;
  color: var(--text-secondary);
  max-width: 480px;
  line-height: 1.7;
}

.section-header.centered .section-desc {
  margin: 0 auto;
}

/* ---- Product Cards (horizontal layout) ---- */
.products-stack {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.product-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: all 0.4s var(--ease);
  cursor: pointer;
  text-decoration: none;
  color: inherit;
}

.product-row:hover {
  border-color: var(--border-hover);
  box-shadow: 0 8px 40px rgba(0, 0, 0, 0.3);
  transform: translateY(-3px);
}

.product-row:nth-child(even) {
  direction: rtl;
}

.product-row:nth-child(even) > * {
  direction: ltr;
}

.product-row-image {
  overflow: hidden;
  height: 280px;
  position: relative;
}

.product-row-image::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(30, 20, 10, 0.35), rgba(15, 17, 21, 0.2));
  mix-blend-mode: multiply;
  pointer-events: none;
  z-index: 1;
}

.product-row-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
  display: block;
  filter: brightness(0.82) saturate(0.85) sepia(0.15);
  transition: transform 0.6s var(--ease), filter 0.4s var(--ease);
}

.product-row:hover .product-row-image img {
  transform: scale(1.04);
  filter: brightness(0.9) saturate(0.95) sepia(0.1);
}

.product-row-body {
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 2.5rem;
}

.product-row-title {
  font-family: var(--font-display);
  font-size: 1.6rem;
  color: var(--text-primary);
  margin-bottom: 0.75rem;
}

.product-row-desc {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 1.5rem;
}

.product-row-link {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  color: var(--accent);
  font-weight: 600;
  font-size: 0.85rem;
  letter-spacing: 0.02em;
  transition: gap 0.3s var(--ease);
}

.product-row:hover .product-row-link {
  gap: 0.75rem;
}

.product-row-link svg {
  width: 15px;
  height: 15px;
}

/* ---- About ---- */
.about-layout {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 4rem;
  align-items: start;
}

.about-text p {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.8;
  margin-bottom: 1.25rem;
}

.about-text p:first-of-type {
  font-size: 1.05rem;
  color: var(--text-primary);
}

.about-numbers {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.number-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 2rem 1.5rem;
  text-align: center;
  transition: border-color 0.25s var(--ease);
}

.number-card:hover {
  border-color: var(--border-hover);
}

.number-val {
  font-family: var(--font-display);
  font-size: 2.8rem;
  color: var(--accent);
  line-height: 1;
  margin-bottom: 0.5rem;
}

.number-label {
  font-size: 0.75rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  font-weight: 600;
}

/* ---- Contact ---- */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1.2fr;
  gap: 4rem;
  align-items: start;
}

.contact-text h3 {
  font-family: var(--font-display);
  font-size: 1.5rem;
  color: var(--text-primary);
  margin-bottom: 1rem;
}

.contact-text p {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.7;
}

.contact-form {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.field {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.field label {
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.field input,
.field textarea {
  padding: 0.8rem 1rem;
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: 0.9rem;
  transition: all 0.25s var(--ease);
  outline: none;
}

.field input:focus,
.field textarea:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-glow);
}

.field textarea {
  resize: vertical;
  min-height: 120px;
}

/* ---- Publications ---- */
.pubs-container {
  max-width: 780px;
  margin: 0 auto;
}

.pub-group {
  margin-bottom: 2.5rem;
}

.pub-group-year {
  font-family: var(--font-display);
  font-size: 1.4rem;
  color: var(--accent);
  margin-bottom: 1rem;
  padding-bottom: 0.6rem;
  border-bottom: 1px solid var(--border);
}

.pub-entry {
  display: block;
  padding: 1rem 1.25rem;
  border-radius: var(--radius-sm);
  margin-bottom: 0.5rem;
  text-decoration: none;
  color: inherit;
  transition: all 0.25s var(--ease);
  border-left: 2px solid transparent;
}

.pub-entry:hover {
  background: var(--bg-card);
  border-left-color: var(--accent);
  padding-left: 1.5rem;
}

.pub-entry.no-pdf {
  cursor: default;
  position: relative;
}

.pub-entry.no-pdf:hover {
  border-left-color: var(--text-muted);
}

.pub-entry.no-pdf::after {
  content: attr(data-tooltip);
  position: absolute;
  bottom: 100%;
  left: 50%;
  transform: translateX(-50%);
  background: var(--accent);
  color: var(--bg-deep);
  padding: 0.5rem 1rem;
  border-radius: 6px;
  font-size: 0.85rem;
  font-weight: 600;
  white-space: nowrap;
  opacity: 0;
  visibility: hidden;
  transition: all 0.2s var(--ease);
  border: none;
  margin-bottom: 6px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.3);
}

.pub-entry.no-pdf:hover::after {
  opacity: 1;
  visibility: visible;
}

.pub-entry-title {
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--text-primary);
  line-height: 1.5;
  margin-bottom: 0.25rem;
}

.pub-entry-authors {
  font-size: 0.82rem;
  color: var(--text-secondary);
}

.pub-entry-venue {
  font-size: 0.78rem;
  color: var(--text-muted);
  font-style: italic;
}

/* ---- Footer ---- */
.footer {
  border-top: 1px solid var(--border);
  padding: 2rem;
  position: relative;
  z-index: 1;
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.footer-copy {
  font-size: 0.78rem;
  color: var(--text-muted);
}

.footer-links {
  display: flex;
  gap: 1.5rem;
}

.footer-links a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.78rem;
  transition: color 0.2s var(--ease);
}

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

/* ---- Utilities ---- */
.hidden { display: none !important; }

.hp-field {
  position: absolute;
  left: -9999px;
  top: -9999px;
  opacity: 0;
  height: 0;
  width: 0;
  z-index: -1;
}

/* Scroll reveal */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s var(--ease), transform 0.6s var(--ease);
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

.reveal-d1 { transition-delay: 0.1s; }
.reveal-d2 { transition-delay: 0.2s; }
.reveal-d3 { transition-delay: 0.3s; }

/* ---- Responsive ---- */
@media (max-width: 900px) {
  .product-row {
    grid-template-columns: 1fr;
  }

  .product-row:nth-child(even) {
    direction: ltr;
  }

  .product-row-image {
    height: 220px;
  }

  .about-layout,
  .contact-grid {
    grid-template-columns: 1fr;
    gap: 2.5rem;
  }
}

@media (max-width: 768px) {
  .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 1rem;
    right: 1rem;
    flex-direction: column;
    background: rgba(15, 17, 21, 0.97);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 1rem;
    gap: 0.25rem;
  }

  .nav-links.open {
    display: flex;
  }

  .nav-toggle {
    display: block;
  }

  .lang-btn {
    margin-left: 0;
    align-self: stretch;
    text-align: center;
  }

  .hero {
    padding: 7rem 1.5rem 4rem;
    min-height: auto;
  }

  .section {
    padding: 4rem 1.5rem;
  }

  .form-row {
    grid-template-columns: 1fr;
  }

  .about-numbers {
    grid-template-columns: 1fr 1fr;
  }

  .footer-inner {
    flex-direction: column;
    gap: 1rem;
    text-align: center;
  }

  .hero-actions {
    flex-direction: column;
    align-items: stretch;
  }

  .btn {
    justify-content: center;
  }
}