@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600&family=Outfit:wght@400;600;700;800&display=swap');

/* Color Variables and Theme Setup */
:root {
  --bg-primary: #ffffff;
  --bg-secondary: #f8fafc;
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --accent: #2563eb;
  --accent-hover: #1d4ed8;
  --border: #e2e8f0;
  --card-bg: rgba(255, 255, 255, 0.8);
  --shadow: 0 10px 30px -10px rgba(0, 0, 0, 0.05);
  --radius-lg: 16px;
  --radius-md: 8px;
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme="dark"] {
  --bg-primary: #090d16;
  --bg-secondary: #131a26;
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --accent: #3b82f6;
  --accent-hover: #60a5fa;
  --border: #1e293b;
  --card-bg: rgba(19, 26, 38, 0.8);
  --shadow: 0 10px 30px -10px rgba(0, 0, 0, 0.3);
}

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

body {
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  transition: background-color 0.3s ease, color 0.3s ease;
  padding: 60px 20px;
}

.container {
  max-width: 900px;
  margin: 0 auto;
}

/* Headings */
h1, h2, h3, h4 {
  font-family: 'Outfit', system-ui, -apple-system, sans-serif;
  color: var(--text-primary);
  font-weight: 700;
}

h1 {
  font-size: 2.5rem;
  line-height: 1.2;
  margin-bottom: 10px;
  text-align: center;
  font-weight: 800;
  background: linear-gradient(135deg, var(--text-primary) 30%, var(--accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

h3 {
  font-size: 1.75rem;
  margin: 40px 0 20px;
  border-bottom: 2px solid var(--border);
  padding-bottom: 8px;
  display: inline-block;
  width: 100%;
}

/* Theme Toggle */
.theme-toggle {
  position: fixed;
  top: 20px;
  right: 20px;
  background: var(--card-bg);
  border: 1px solid var(--border);
  color: var(--text-primary);
  padding: 10px 14px;
  border-radius: 50%;
  cursor: pointer;
  box-shadow: var(--shadow);
  transition: var(--transition);
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  backdrop-filter: blur(10px);
}

.theme-toggle:hover {
  transform: scale(1.1);
  border-color: var(--accent);
}

/* Header & Authors */
header {
  text-align: center;
  margin-bottom: 40px;
}

.venue {
  font-size: 1.1rem;
  color: var(--accent);
  font-weight: 600;
  margin-bottom: 20px;
  text-transform: uppercase;
  letter-spacing: 1px;
}

.authors {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 20px 30px;
  margin-bottom: 20px;
  list-style: none;
}

.authors li {
  text-align: center;
}

.authors a {
  color: var(--text-primary);
  text-decoration: none;
  font-weight: 500;
  transition: var(--transition);
}

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

.institution {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-top: 4px;
}

.affiliations {
  color: var(--text-secondary);
  font-size: 0.95rem;
  margin-top: 15px;
}

/* Links Buttons Grid */
.links-grid {
  display: flex;
  justify-content: center;
  gap: 15px;
  margin: 30px 0;
  flex-wrap: wrap;
}

.btn-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background-color: var(--card-bg);
  border: 1px solid var(--border);
  color: var(--text-primary);
  padding: 12px 24px;
  border-radius: 30px;
  text-decoration: none;
  font-weight: 600;
  font-size: 0.95rem;
  box-shadow: var(--shadow);
  transition: var(--transition);
  backdrop-filter: blur(10px);
}

.btn-link:hover {
  background-color: var(--accent);
  color: #ffffff;
  border-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: 0 10px 20px -5px rgba(37, 99, 235, 0.3);
}

.btn-link svg {
  width: 18px;
  height: 18px;
  fill: currentColor;
}

/* Section Common Styles */
section {
  margin-bottom: 40px;
}

p.abstract-text {
  text-align: justify;
  font-size: 1.05rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* Figure & Image Styling */
figure {
  margin: 30px 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 15px;
}

figure img {
  width: 100%;
  padding: 16px;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  transition: var(--transition);
  background-color: #ffffff;
}

figure img:hover {
  transform: scale(1.01);
}

figcaption {
  font-size: 0.9rem;
  color: var(--text-secondary);
  text-align: center;
  max-width: 90%;
  line-height: 1.5;
}

/* Multi-image Grid for User Studies */
.study-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 30px;
  margin: 30px 0;
}

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

/* Citation & Bibtex Box */
.citation-container {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 20px;
  position: relative;
  margin-top: 15px;
}

.bibtex-code {
  font-family: 'Fira Code', 'Courier New', Courier, monospace;
  font-size: 0.85rem;
  color: var(--text-primary);
  white-space: pre;
  overflow-x: auto;
  display: block;
}

.btn-copy {
  position: absolute;
  top: 15px;
  right: 15px;
  background-color: var(--card-bg);
  border: 1px solid var(--border);
  color: var(--text-primary);
  padding: 6px 12px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.8rem;
  font-weight: 600;
  transition: var(--transition);
  display: flex;
  align-items: center;
  gap: 4px;
}

.btn-copy:hover {
  background-color: var(--accent);
  color: white;
  border-color: var(--accent);
}

/* Footer style */
footer {
  margin-top: 80px;
  border-top: 1px solid var(--border);
  padding-top: 20px;
  text-align: center;
  font-size: 0.85rem;
  color: var(--text-secondary);
}

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

.animate-fade-in {
  animation: fadeIn 0.8s ease-out forwards;
}