/* ============================================
   Components — Nav, Cards, Buttons, Tags, Footer
   ============================================ */

/* ---- Navigation ---- */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(250,250,250,0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  transition: background var(--transition-slow), border-color var(--transition-slow);
}

[data-theme="dark"] .nav {
  background: rgba(15,13,26,0.85);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

.nav-logo {
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--text);
  transition: color var(--transition-fast);
}

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

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
}

.nav-links a {
  color: var(--text-muted);
  font-weight: 500;
  font-size: 0.95rem;
  transition: color var(--transition-fast);
  position: relative;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--primary-light);
  transition: width var(--transition-base);
  border-radius: 1px;
}

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

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

/* Theme toggle button */
.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-full);
  background: var(--bg-alt);
  transition: background var(--transition-fast), transform var(--transition-fast);
}

.theme-toggle:hover {
  background: var(--surface-hover);
  transform: rotate(15deg);
}

.theme-toggle svg {
  width: 20px;
  height: 20px;
}

/* Mobile hamburger */
.mobile-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  padding: 8px;
}

.mobile-toggle span {
  display: block;
  height: 2px;
  background: var(--text);
  border-radius: 2px;
  transition: transform var(--transition-base), opacity var(--transition-base);
}

.mobile-toggle.open span:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}
.mobile-toggle.open span:nth-child(2) {
  opacity: 0;
}
.mobile-toggle.open span:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

@media (max-width: 767px) {
  .mobile-toggle {
    display: flex;
  }

  .nav-links {
    position: fixed;
    top: 64px;
    left: 0;
    right: 0;
    bottom: 0;
    flex-direction: column;
    justify-content: flex-start;
    padding-top: var(--space-2xl);
    gap: var(--space-xl);
    background: var(--bg);
    transform: translateX(100%);
    transition: transform var(--transition-base);
  }

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

  .nav-links a {
    font-size: 1.25rem;
  }
}

/* ---- Spacer for fixed nav ---- */
.nav-spacer {
  height: 64px;
}

/* ---- Cards ---- */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: var(--space-xl);
  transition:
    transform var(--transition-base),
    box-shadow var(--transition-base),
    border-color var(--transition-base);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--primary-light);
}

.card-title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: var(--space-sm);
}

.card-title a {
  color: var(--text);
  transition: color var(--transition-fast);
}

.card-title a:hover {
  color: var(--primary-light);
}

.card-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-sm);
  color: var(--text-muted);
  font-size: 0.875rem;
  margin-bottom: var(--space-md);
}

.card-meta span::before {
  content: '·';
  margin-right: var(--space-sm);
}

.card-meta span:first-child::before {
  display: none;
}

.card-excerpt {
  color: var(--text-muted);
  margin-bottom: var(--space-md);
  line-height: 1.6;
}

.card-thumbnail {
  width: 100%;
  height: 180px;
  object-fit: cover;
  border-radius: var(--radius-sm);
  margin-bottom: var(--space-md);
  background: var(--bg-alt);
}

.card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-sm);
  margin-top: var(--space-md);
}

/* ---- Buttons ---- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: 0.75rem 1.5rem;
  font-weight: 600;
  font-size: 0.95rem;
  border-radius: var(--radius-full);
  transition:
    transform var(--transition-fast),
    box-shadow var(--transition-fast),
    background var(--transition-fast);
}

.btn:hover {
  transform: translateY(-2px);
}

.btn-primary {
  background: var(--primary);
  color: #fff;
  box-shadow: 0 4px 14px rgba(108,60,225,0.35);
}

.btn-primary:hover {
  background: var(--primary-light);
  color: #fff;
  box-shadow: 0 6px 20px rgba(108,60,225,0.45);
}

.btn-outline {
  border: 2px solid var(--primary-light);
  color: var(--primary-light);
}

.btn-outline:hover {
  background: var(--primary-light);
  color: #fff;
}

.btn-ghost {
  color: var(--primary-light);
  padding: 0.5rem 1rem;
}

.btn-ghost:hover {
  background: var(--bg-alt);
}

.btn-sm {
  padding: 0.4rem 1rem;
  font-size: 0.85rem;
}

/* ---- Tags ---- */
.tag {
  display: inline-block;
  padding: 0.2rem 0.65rem;
  font-size: 0.75rem;
  font-weight: 600;
  border-radius: var(--radius-full);
  background: var(--bg-alt);
  color: var(--primary-light);
  border: 1px solid var(--border);
  transition: background var(--transition-fast);
}

.tag:hover {
  background: var(--surface-hover);
}

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

/* Status badges for research */
.badge {
  display: inline-block;
  padding: 0.2rem 0.75rem;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  border-radius: var(--radius-full);
}

.badge-published {
  background: rgba(16,185,129,0.15);
  color: #10B981;
}

.badge-preprint {
  background: rgba(251,146,60,0.15);
  color: #FB923C;
}

.badge-wip {
  background: rgba(108,60,225,0.15);
  color: #A855F7;
}

/* ---- Footer ---- */
.footer {
  background: var(--bg-alt);
  border-top: 3px solid;
  border-image: var(--hero-gradient) 1;
  padding: var(--space-3xl) 0 var(--space-xl);
  margin-top: var(--space-4xl);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-2xl);
  margin-bottom: var(--space-2xl);
}

@media (min-width: 640px) {
  .footer-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.footer h4 {
  font-size: 1rem;
  margin-bottom: var(--space-md);
  color: var(--text);
}

.footer a {
  display: block;
  color: var(--text-muted);
  padding: var(--space-xs) 0;
  font-size: 0.9rem;
  transition: color var(--transition-fast);
}

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

.footer-bottom {
  text-align: center;
  padding-top: var(--space-xl);
  border-top: 1px solid var(--border);
  color: var(--text-muted);
  font-size: 0.85rem;
}

/* ---- Hero Section ---- */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  background: linear-gradient(135deg, #9678e0, #7ecae6, #e8a5cc, #9678e0);
  background-size: 400% 400%;
  animation: gradient-shift 12s ease infinite;
  overflow: hidden;
}

[data-theme="dark"] .hero {
  background: #0F0D1A;
  animation: none;
}

#hero-nodes-canvas {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 0;
}

.hero-content {
  position: relative;
  z-index: 1;
  padding: var(--space-2xl);
}

.hero h1 {
  font-size: clamp(2.5rem, 7vw, 5rem);
  font-weight: 900;
  color: #fff;
  margin-bottom: var(--space-md);
  letter-spacing: -0.02em;
}

.hero p {
  font-size: clamp(1.1rem, 2.5vw, 1.4rem);
  color: rgba(255,255,255,0.9);
  max-width: 600px;
  margin: 0 auto var(--space-xl);
}

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

.hero .btn-primary {
  background: #fff;
  color: var(--primary);
  box-shadow: 0 4px 14px rgba(0,0,0,0.2);
}

.hero .btn-primary:hover {
  background: #f0f0f0;
  color: var(--primary);
  box-shadow: 0 6px 20px rgba(0,0,0,0.3);
}

.hero .btn-outline {
  border-color: rgba(255,255,255,0.6);
  color: #fff;
}

.hero .btn-outline:hover {
  background: rgba(255,255,255,0.15);
  border-color: #fff;
  color: #fff;
}

/* ---- Visitor map section ---- */
.map-section {
  background: var(--bg-alt);
}

.map-wrapper {
  max-width: 800px;
  margin: 0 auto;
  position: relative;
}

.map-canvas {
  width: 100%;
  border-radius: var(--radius-md);
  border: 1px solid var(--border);
  background: var(--surface);
  image-rendering: pixelated;
}

.map-stats {
  text-align: center;
  margin-top: var(--space-lg);
  color: var(--text-muted);
  font-size: 0.95rem;
}

.map-stats strong {
  color: var(--primary-light);
  font-weight: 700;
}

/* ---- Post header (single post pages) ---- */
.post-header {
  text-align: center;
  padding: var(--space-3xl) 0 var(--space-xl);
}

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

.post-meta {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: var(--space-sm);
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-bottom: var(--space-lg);
}

/* ---- Back link ---- */
.back-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  color: var(--primary-light);
  font-weight: 500;
  margin-bottom: var(--space-xl);
}

.back-link:hover {
  color: var(--accent-pink);
}

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

@media (min-width: 768px) {
  .about-grid {
    grid-template-columns: 280px 1fr;
  }
}

.about-photo {
  width: 100%;
  max-width: 280px;
  border-radius: var(--radius-lg);
  border: 3px solid var(--border);
}

/* ---- Social links ---- */
.social-links {
  display: flex;
  gap: var(--space-md);
  flex-wrap: wrap;
}

.social-links a {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  padding: 0.5rem 1rem;
  background: var(--bg-alt);
  border-radius: var(--radius-full);
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-muted);
  border: 1px solid var(--border);
  transition: all var(--transition-fast);
}

.social-links a:hover {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}

/* ---- BibTeX block ---- */
.bibtex-block {
  position: relative;
  background: var(--bg-alt);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: var(--space-lg);
  margin: var(--space-xl) 0;
}

.bibtex-block pre {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  white-space: pre-wrap;
  word-break: break-all;
}

.bibtex-copy {
  position: absolute;
  top: var(--space-sm);
  right: var(--space-sm);
}

/* ---- Language toggle ---- */
.lang-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-full);
  background: var(--bg-alt);
  font-weight: 700;
  font-size: 0.85rem;
  transition: background var(--transition-fast), transform var(--transition-fast);
}

.lang-toggle:hover {
  background: var(--surface-hover);
  transform: scale(1.05);
}

/* ---- Comments section ---- */
.comments-section {
  border-top: 1px solid var(--border);
  padding-top: var(--space-2xl);
  margin-top: var(--space-2xl);
}

.comments-section .container {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: var(--space-xl);
}

.comments-title {
  text-align: center;
  margin-bottom: var(--space-xl);
  font-size: 1.25rem;
}

/* Comment form */
.comment-form {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
  margin-bottom: var(--space-xl);
}

.comment-form input[type="text"],
.comment-form textarea {
  width: 100%;
  padding: 0.75rem 1rem;
  font-family: var(--font-sans);
  font-size: 0.95rem;
  color: var(--text);
  background: var(--bg-alt);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
  resize: vertical;
}

.comment-form input[type="text"]:focus,
.comment-form textarea:focus {
  outline: none;
  border-color: var(--primary-light);
  box-shadow: 0 0 0 3px rgba(108, 60, 225, 0.15);
}

.comment-form textarea {
  min-height: 100px;
}

.comment-form button {
  align-self: flex-end;
}

/* Comment list */
.comments-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
}

.comments-empty {
  text-align: center;
  color: var(--text-muted);
  font-size: 0.9rem;
  padding: var(--space-xl) 0;
}

.comment-item {
  display: flex;
  gap: var(--space-md);
  padding: var(--space-md);
  background: var(--bg-alt);
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
}

.comment-avatar {
  flex-shrink: 0;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-weight: 700;
  font-size: 0.85rem;
}

.comment-body {
  flex: 1;
  min-width: 0;
}

.comment-meta {
  display: flex;
  align-items: baseline;
  gap: var(--space-sm);
  margin-bottom: var(--space-xs);
}

.comment-author {
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--text);
}

.comment-time {
  font-size: 0.75rem;
  color: var(--text-muted);
}

.comment-text {
  font-size: 0.9rem;
  line-height: 1.6;
  color: var(--text);
  white-space: pre-wrap;
  word-break: break-word;
}

/* Reply button */
.comment-reply-btn {
  margin-top: var(--space-sm);
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--primary-light);
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.2rem 0;
  transition: color var(--transition-fast);
}

.comment-reply-btn:hover {
  color: var(--accent-pink);
  text-decoration: underline;
}

/* Indented replies */
.comment-replies {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
  margin-left: calc(36px + var(--space-md));
  padding-left: var(--space-md);
  border-left: 2px solid var(--border);
}

.comment-item--reply .comment-avatar {
  width: 28px;
  height: 28px;
  font-size: 0.75rem;
}

/* Inline reply form */
.reply-form-inline {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  margin-top: var(--space-md);
  padding-top: var(--space-md);
  border-top: 1px solid var(--border);
}

.reply-form-inline input,
.reply-form-inline textarea {
  width: 100%;
  padding: 0.6rem 0.8rem;
  font-family: var(--font-sans);
  font-size: 0.85rem;
  color: var(--text);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
  resize: vertical;
}

.reply-form-inline input:focus,
.reply-form-inline textarea:focus {
  outline: none;
  border-color: var(--primary-light);
  box-shadow: 0 0 0 3px rgba(108, 60, 225, 0.15);
}

.reply-form-inline textarea {
  min-height: 70px;
}

.reply-form-actions {
  display: flex;
  justify-content: flex-end;
  gap: var(--space-sm);
}

/* ---- 404 page ---- */
.error-page {
  min-height: 80vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: var(--space-2xl);
}

.error-page h1 {
  font-size: clamp(4rem, 15vw, 10rem);
  font-weight: 900;
}

.error-page p {
  font-size: 1.25rem;
  color: var(--text-muted);
  margin: var(--space-md) 0 var(--space-xl);
}