/* ===== RESET & BASE ===== */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }

:root {
  --primary: #0a1628;
  --accent: #1a73e8;
  --accent-hover: #1557b0;
  --text: #333;
  --text-light: #666;
  --bg: #fff;
  --bg-light: #f7f8fa;
  --border: #e0e4ea;
  --radius: 8px;
  --max-width: 1140px;
  --transition: 0.3s ease;
}

html { scroll-behavior: smooth; }

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a { text-decoration: none; color: inherit; }
img { max-width: 100%; display: block; }

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* ===== HEADER ===== */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(255,255,255,0.97);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
  transition: box-shadow var(--transition);
}

.header.scrolled {
  box-shadow: 0 2px 20px rgba(0,0,0,0.08);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--primary);
  letter-spacing: -0.02em;
  white-space: nowrap;
}

.logo-img {
  height: 38px;
  width: 38px;
  object-fit: contain;
  border-radius: 4px;
}

.logo span {
  color: var(--accent);
}

.nav {
  display: flex;
  align-items: center;
  gap: 8px;
}

.lang-switch {
  display: flex;
  align-items: center;
  gap: 4px;
  background: var(--bg-light);
  border-radius: 20px;
  padding: 4px;
}

.lang-switch a {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  border-radius: 16px;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-light);
  transition: all var(--transition);
}

.lang-switch a:hover {
  color: var(--text);
}

.lang-switch a.active {
  background: var(--bg);
  color: var(--primary);
  box-shadow: 0 1px 4px rgba(0,0,0,0.1);
}

.lang-switch img {
  width: 20px;
  height: 14px;
  border-radius: 2px;
  object-fit: cover;
}

/* ===== HERO ===== */
.hero {
  position: relative;
  margin-top: 72px;
  height: 520px;
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, #0a1628 0%, #1a2d4a 50%, #0d2137 100%);
  z-index: 0;
}

.hero-bg::after {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 20% 50%, rgba(26,115,232,0.15) 0%, transparent 50%),
    radial-gradient(circle at 80% 30%, rgba(26,115,232,0.1) 0%, transparent 40%);
}

.hero-bg img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.25;
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 700px;
  padding: 0 24px;
}

.hero-title {
  font-size: 3rem;
  font-weight: 800;
  color: #fff;
  letter-spacing: -0.02em;
  margin-bottom: 16px;
  line-height: 1.15;
}

.hero-divider {
  width: 80px;
  height: 3px;
  background: var(--accent);
  margin: 0 auto 20px;
  border-radius: 2px;
}

.hero-subtitle {
  font-size: 1.15rem;
  color: rgba(255,255,255,0.7);
  font-weight: 400;
  line-height: 1.6;
}

.hero-subtitle:empty {
  display: none;
}

/* ===== GRID PATTERN OVERLAY ===== */
.hero-grid {
  position: absolute;
  inset: 0;
  z-index: 0;
  opacity: 0.06;
  background-image:
    linear-gradient(rgba(255,255,255,0.5) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.5) 1px, transparent 1px);
  background-size: 60px 60px;
}

/* ===== CIRCUIT DOTS ===== */
.hero-dots {
  position: absolute;
  inset: 0;
  z-index: 0;
  overflow: hidden;
}

.hero-dots span {
  position: absolute;
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: rgba(26,115,232,0.4);
  animation: pulse 3s ease-in-out infinite;
}

.hero-dots span:nth-child(1) { top: 15%; left: 10%; animation-delay: 0s; }
.hero-dots span:nth-child(2) { top: 25%; left: 85%; animation-delay: 0.5s; }
.hero-dots span:nth-child(3) { top: 60%; left: 20%; animation-delay: 1s; }
.hero-dots span:nth-child(4) { top: 70%; left: 75%; animation-delay: 1.5s; }
.hero-dots span:nth-child(5) { top: 40%; left: 50%; animation-delay: 2s; }
.hero-dots span:nth-child(6) { top: 80%; left: 40%; animation-delay: 0.8s; }
.hero-dots span:nth-child(7) { top: 10%; left: 60%; animation-delay: 2.2s; }
.hero-dots span:nth-child(8) { top: 50%; left: 90%; animation-delay: 1.3s; }

@keyframes pulse {
  0%, 100% { opacity: 0.3; transform: scale(1); }
  50% { opacity: 1; transform: scale(2); }
}

/* ===== PUBLICATIONS SECTION ===== */
.publications {
  padding: 80px 0;
}

.section-header {
  text-align: center;
  margin-bottom: 48px;
}

.section-title {
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 12px;
}

.section-divider {
  width: 60px;
  height: 3px;
  background: var(--accent);
  margin: 0 auto;
  border-radius: 2px;
}

/* ===== TABLE ===== */
.pub-table {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}

.pub-table thead {
  background: var(--primary);
}

.pub-table th {
  padding: 14px 20px;
  text-align: left;
  font-size: 0.85rem;
  font-weight: 600;
  color: #fff;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.pub-table th:last-child {
  text-align: center;
  width: 120px;
}

.pub-table td {
  padding: 16px 20px;
  font-size: 0.95rem;
  border-bottom: 1px solid var(--border);
  vertical-align: middle;
}

.pub-table tr:last-child td {
  border-bottom: none;
}

.pub-table tbody tr {
  transition: background var(--transition);
}

.pub-table tbody tr:hover {
  background: var(--bg-light);
}

.pub-table .date-col {
  white-space: nowrap;
  color: var(--text-light);
  font-size: 0.9rem;
  width: 140px;
}

.pub-table .download-col {
  text-align: center;
}

.btn-download {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 16px;
  background: var(--accent);
  color: #fff;
  border-radius: 6px;
  font-size: 0.8rem;
  font-weight: 600;
  transition: all var(--transition);
}

.btn-download:hover {
  background: var(--accent-hover);
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(26,115,232,0.3);
}

.btn-download svg {
  width: 14px;
  height: 14px;
}

.pub-empty {
  text-align: center;
  padding: 60px 20px;
  color: var(--text-light);
  font-size: 0.95rem;
}

/* ===== FOOTER ===== */
.footer {
  background: var(--primary);
  color: rgba(255,255,255,0.6);
  padding: 40px 0;
  text-align: center;
  font-size: 0.85rem;
}

.footer-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}

.footer-logo {
  font-size: 1.1rem;
  font-weight: 700;
  color: #fff;
}

.footer-divider {
  width: 40px;
  height: 1px;
  background: rgba(255,255,255,0.15);
}

/* ===== RESPONSIVE ===== */
@media (max-width: 768px) {
  .header-inner { height: 60px; }
  .logo { font-size: 1.1rem; }
  .hero { margin-top: 60px; height: 400px; }
  .hero-title { font-size: 2rem; }
  .hero-subtitle { font-size: 1rem; }
  .publications { padding: 48px 0; }
  .section-title { font-size: 1.4rem; }

  .pub-table-wrap { overflow-x: auto; -webkit-overflow-scrolling: touch; }

  .pub-table th,
  .pub-table td { padding: 12px 14px; font-size: 0.85rem; }

  .lang-switch a { padding: 5px 10px; font-size: 0.8rem; }

  .btn-download { padding: 6px 12px; font-size: 0.75rem; }
}

@media (max-width: 480px) {
  .hero { height: 340px; }
  .hero-title { font-size: 1.6rem; }
  .pub-table .date-col { width: auto; }
}

/* ===== ANIMATIONS ===== */
.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

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