/* Base Styles */
:root {
  --primary-color: #4a6fdc;
  --primary-dark: #3a5fc9;
  --secondary-color: #6c757d;
  --success-color: #28a745;
  --danger-color: #dc3545;
  --warning-color: #ffc107;
  --info-color: #17a2b8;
  --light-color: #f8f9fa;
  --dark-color: #343a40;
  --body-bg-light: #ffffff;
  --body-text-light: #333333;
  --card-bg-light: #ffffff;
  --border-light: #e0e0e0;
  --body-bg-dark: #121212;
  --body-text-dark: #e0e0e0;
  --card-bg-dark: #1e1e1e;
  --border-dark: #333333;
  --font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  --transition-speed: 0.3s;
  --box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
  --border-radius: 8px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family);
  line-height: 1.6;
  transition: background-color var(--transition-speed), color var(--transition-speed);
}

.light-mode {
  background-color: var(--body-bg-light);
  color: var(--body-text-light);
}

.dark-mode {
  background-color: var(--body-bg-dark);
  color: var(--body-text-dark);
}

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

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

a:hover {
  color: var(--primary-dark);
}

ul {
  list-style: none;
}

img {
  max-width: 100%;
  height: auto;
}

/* Button Styles */
.btn {
  display: inline-block;
  padding: 10px 20px;
  border-radius: var(--border-radius);
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-speed);
  border: none;
  font-size: 16px;
}

.btn-primary {
  background-color: var(--primary-color);
  color: white;
}

.btn-primary:hover {
  background-color: var(--primary-dark);
}

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

.btn-outline:hover {
  background-color: var(--primary-color);
  color: white;
}

.btn-block {
  display: block;
  width: 100%;
}

.btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

/* Header Styles */
header {
  position: sticky;
  top: 0;
  z-index: 1000;
  padding: 15px 0;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
  transition: background-color var(--transition-speed);
}

.light-mode header {
  background-color: white;
}

.dark-mode header {
  background-color: #1a1a1a;
}

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

.logo h1 {
  font-size: 24px;
  font-weight: 700;
}

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

.nav-links {
  display: flex;
}

.nav-links li {
  margin: 0 15px;
}

.nav-links a {
  color: inherit;
  font-weight: 500;
  position: relative;
}

.nav-links a::after {
  content: "";
  position: absolute;
  width: 0;
  height: 2px;
  bottom: -5px;
  left: 0;
  background-color: var(--primary-color);
  transition: width var(--transition-speed);
}

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

.header-right {
  display: flex;
  align-items: center;
}

.auth-buttons {
  display: flex;
  gap: 10px;
  margin-left: 20px;
}

#theme-toggle {
  background: none;
  border: none;
  cursor: pointer;
  font-size: 20px;
  color: inherit;
  transition: transform var(--transition-speed);
}

#theme-toggle:hover {
  transform: rotate(15deg);
}

.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  margin-left: 15px;
}

.mobile-menu-btn span {
  display: block;
  width: 25px;
  height: 3px;
  margin: 5px 0;
  transition: all var(--transition-speed);
}

.light-mode .mobile-menu-btn span {
  background-color: var(--dark-color);
}

.dark-mode .mobile-menu-btn span {
  background-color: var(--light-color);
}

.mobile-menu {
  display: none;
  position: fixed;
  top: 70px;
  left: 0;
  width: 100%;
  padding: 20px;
  z-index: 999;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
  transition: transform 0.3s ease-in-out;
  transform: translateY(-100%);
}

.light-mode .mobile-menu {
  background-color: white;
}

.dark-mode .mobile-menu {
  background-color: #1a1a1a;
}

.mobile-menu.active {
  transform: translateY(0);
}

.mobile-menu ul {
  display: flex;
  flex-direction: column;
  gap: 15px;
}

.mobile-menu a {
  display: block;
  padding: 10px 0;
  font-size: 18px;
}

.mobile-auth {
  margin-top: 15px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

/* Hero Section */
.hero {
  padding: 80px 0;
  background: linear-gradient(135deg, #f5f7ff 0%, #e0e6ff 100%);
  text-align: center;
}

.dark-mode .hero {
  background: linear-gradient(135deg, #2a2d3a 0%, #1a1d2a 100%);
}

.hero-content {
  max-width: 800px;
  margin: 0 auto;
}

.hero h2 {
  font-size: 42px;
  margin-bottom: 20px;
  font-weight: 700;
}

.hero p {
  font-size: 18px;
  margin-bottom: 30px;
  color: var(--secondary-color);
}

.search-container {
  display: flex;
  max-width: 600px;
  margin: 0 auto 20px;
}

.search-container input {
  flex: 1;
  padding: 15px;
  border: 1px solid var(--border-light);
  border-radius: var(--border-radius) 0 0 var(--border-radius);
  font-size: 16px;
  transition: border-color var(--transition-speed);
}

.dark-mode .search-container input {
  background-color: #2a2d3a;
  color: var(--body-text-dark);
  border-color: var(--border-dark);
}

.search-container input:focus {
  outline: none;
  border-color: var(--primary-color);
}

.search-container button {
  border-radius: 0 var(--border-radius) var(--border-radius) 0;
  padding: 15px 25px;
}

.quick-filters {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px;
  margin-top: 20px;
}

.quick-filters span {
  margin-right: 10px;
  color: var(--secondary-color);
}

.filter-btn {
  background-color: transparent;
  border: 1px solid var(--border-light);
  border-radius: 20px;
  padding: 5px 15px;
  cursor: pointer;
  transition: all var(--transition-speed);
}

.dark-mode .filter-btn {
  border-color: var(--border-dark);
}

.filter-btn:hover {
  background-color: var(--primary-color);
  color: white;
  border-color: var(--primary-color);
}

/* Papers Section */
.papers-section {
  padding: 80px 0;
}

.section-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 30px;
}

.section-header h2 {
  font-size: 32px;
  font-weight: 700;
}

.view-options {
  display: flex;
  align-items: center;
  gap: 15px;
}

.view-btn {
  background: none;
  border: none;
  font-size: 18px;
  cursor: pointer;
  color: var(--secondary-color);
  transition: color var(--transition-speed);
}

.view-btn.active {
  color: var(--primary-color);
}

#sort-options {
  padding: 8px 15px;
  border-radius: var(--border-radius);
  border: 1px solid var(--border-light);
  background-color: transparent;
  color: inherit;
  cursor: pointer;
}

.dark-mode #sort-options {
  background-color: #2a2d3a;
  border-color: var(--border-dark);
}

.papers-container {
  margin-bottom: 40px;
}

.grid-view {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 30px;
}

.list-view {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.paper-card {
  border-radius: var(--border-radius);
  overflow: hidden;
  transition: transform var(--transition-speed), box-shadow var(--transition-speed);
}

.light-mode .paper-card {
  background-color: white;
  box-shadow: var(--box-shadow);
  border: 1px solid var(--border-light);
}

.dark-mode .paper-card {
  background-color: var(--card-bg-dark);
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
  border: 1px solid var(--border-dark);
}

.paper-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
}

.grid-view .paper-card {
  display: flex;
  flex-direction: column;
}

.list-view .paper-card {
  display: flex;
  flex-direction: row;
}

.list-view .paper-image {
  width: 200px;
  min-width: 200px;
}

.paper-image img {
  width: 100%;
  height: 200px;
  object-fit: cover;
}

.paper-content {
  padding: 20px;
  flex: 1;
}

.paper-category {
  display: inline-block;
  background-color: rgba(74, 111, 220, 0.1);
  color: var(--primary-color);
  padding: 5px 10px;
  border-radius: 4px;
  font-size: 14px;
  margin-bottom: 10px;
}

.paper-title {
  font-size: 18px;
  margin-bottom: 10px;
  font-weight: 600;
}

.paper-authors {
  color: var(--secondary-color);
  font-size: 14px;
  margin-bottom: 10px;
}

.paper-abstract {
  margin-bottom: 15px;
  font-size: 14px;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.list-view .paper-abstract {
  -webkit-line-clamp: 2;
}

.paper-meta {
  display: flex;
  justify-content: space-between;
  font-size: 14px;
  color: var(--secondary-color);
}

.paper-date {
  display: flex;
  align-items: center;
  gap: 5px;
}

.paper-citations {
  display: flex;
  align-items: center;
  gap: 5px;
}

.paper-actions {
  display: flex;
  justify-content: space-between;
  margin-top: 15px;
}

.action-btn {
  background: none;
  border: none;
  color: var(--primary-color);
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 5px;
  font-size: 14px;
  transition: color var(--transition-speed);
}

.action-btn:hover {
  color: var(--primary-dark);
}

.pagination {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 20px;
}

.pagination-btn {
  background: none;
  border: none;
  color: var(--primary-color);
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 5px;
  transition: color var(--transition-speed);
}

.pagination-btn:hover:not(:disabled) {
  color: var(--primary-dark);
}

.pagination-btn:disabled {
  color: var(--secondary-color);
  cursor: not-allowed;
  opacity: 0.6;
}

.page-numbers {
  font-size: 14px;
}

/* Categories Section */
.categories-section {
  padding: 80px 0;
  background-color: #f9f9f9;
}

.dark-mode .categories-section {
  background-color: #1a1a1a;
}

.categories-section h2 {
  text-align: center;
  font-size: 32px;
  margin-bottom: 40px;
  font-weight: 700;
}

.categories-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  gap: 30px;
}

.category-card {
  padding: 30px;
  border-radius: var(--border-radius);
  text-align: center;
  transition: transform var(--transition-speed), box-shadow var(--transition-speed);
  cursor: pointer;
}

.light-mode .category-card {
  background-color: white;
  box-shadow: var(--box-shadow);
}

.dark-mode .category-card {
  background-color: var(--card-bg-dark);
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
}

.category-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
}

.category-icon {
  font-size: 36px;
  color: var(--primary-color);
  margin-bottom: 15px;
}

.category-card h3 {
  font-size: 18px;
  margin-bottom: 10px;
}

.category-card p {
  color: var(--secondary-color);
  font-size: 14px;
}

/* Stats Section */
.stats-section {
  padding: 60px 0;
  background-color: var(--primary-color);
  color: white;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 30px;
}

.stat-card {
  text-align: center;
}

.stat-number {
  font-size: 48px;
  font-weight: 700;
  margin-bottom: 10px;
}

.stat-label {
  font-size: 18px;
  opacity: 0.9;
}

/* About Section */
.about-section {
  padding: 80px 0;
}

.about-content {
  display: flex;
  align-items: center;
  gap: 50px;
}

.about-text {
  flex: 1;
}

.about-text h2 {
  font-size: 32px;
  margin-bottom: 20px;
  font-weight: 700;
}

.about-text p {
  margin-bottom: 20px;
}

.about-image {
  flex: 1;
  border-radius: var(--border-radius);
  overflow: hidden;
}

/* Newsletter Section */
.newsletter-section {
  padding: 60px 0;
  background-color: #f5f7ff;
}

.dark-mode .newsletter-section {
  background-color: #2a2d3a;
}

.newsletter-content {
  max-width: 600px;
  margin: 0 auto;
  text-align: center;
}

.newsletter-content h2 {
  font-size: 32px;
  margin-bottom: 15px;
  font-weight: 700;
}

.newsletter-content p {
  margin-bottom: 30px;
  color: var(--secondary-color);
}

.newsletter-form {
  display: flex;
  gap: 10px;
  margin-bottom: 15px;
}

.newsletter-form input {
  flex: 1;
  padding: 12px 15px;
  border: 1px solid var(--border-light);
  border-radius: var(--border-radius);
  font-size: 16px;
}

.dark-mode .newsletter-form input {
  background-color: #1a1a1a;
  color: var(--body-text-dark);
  border-color: var(--border-dark);
}

.form-message {
  font-size: 14px;
  margin-top: 10px;
  min-height: 20px;
}

/* Footer */
footer {
  padding: 60px 0 20px;
  background-color: #2c3e50;
  color: white;
}

.footer-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 40px;
  margin-bottom: 40px;
}

.footer-column h3 {
  font-size: 18px;
  margin-bottom: 20px;
  font-weight: 600;
}

.footer-logo h2 {
  font-size: 24px;
  margin-bottom: 15px;
}

.footer-logo span {
  color: #6c9ff8;
}

.footer-column p {
  margin-bottom: 20px;
  opacity: 0.8;
}

.footer-column ul li {
  margin-bottom: 10px;
}

.footer-column ul li a {
  color: #b3c5d7;
  transition: color var(--transition-speed);
}

.footer-column ul li a:hover {
  color: white;
}

.social-links {
  display: flex;
  gap: 15px;
}

.social-links a {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  background-color: rgba(255, 255, 255, 0.1);
  border-radius: 50%;
  color: white;
  transition: background-color var(--transition-speed);
}

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

.footer-bottom {
  text-align: center;
  padding-top: 20px;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  font-size: 14px;
  opacity: 0.7;
}

/* Modal Styles */
.modal {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.5);
  z-index: 1100;
  align-items: center;
  justify-content: center;
}

.modal-content {
  position: relative;
  width: 90%;
  max-width: 500px;
  max-height: 90vh;
  overflow-y: auto;
  border-radius: var(--border-radius);
  padding: 30px;
}

.light-mode .modal-content {
  background-color: white;
}

.dark-mode .modal-content {
  background-color: var(--card-bg-dark);
}

.paper-modal-content {
  max-width: 800px;
}

.close-modal {
  position: absolute;
  top: 15px;
  right: 15px;
  font-size: 24px;
  background: none;
  border: none;
  cursor: pointer;
  color: var(--secondary-color);
}

.modal h2 {
  margin-bottom: 20px;
  font-size: 24px;
  text-align: center;
}

.form-group {
  margin-bottom: 20px;
}

.form-group label {
  display: block;
  margin-bottom: 8px;
  font-weight: 500;
}

.form-group input {
  width: 100%;
  padding: 12px 15px;
  border: 1px solid var(--border-light);
  border-radius: var(--border-radius);
  font-size: 16px;
}

.dark-mode .form-group input {
  background-color: #2a2d3a;
  color: var(--body-text-dark);
  border-color: var(--border-dark);
}

.form-checkbox {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 20px;
}

.form-checkbox input {
  width: 18px;
  height: 18px;
}

.forgot-password {
  display: block;
  text-align: right;
  font-size: 14px;
  margin-top: 5px;
}

.modal-footer {
  margin-top: 20px;
  text-align: center;
  font-size: 14px;
}

/* Paper Details */
.paper-details {
  padding: 20px;
}

.paper-details-header {
  margin-bottom: 30px;
}

.paper-details-title {
  font-size: 24px;
  margin-bottom: 15px;
  font-weight: 700;
}

.paper-details-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
  margin-bottom: 20px;
  font-size: 14px;
  color: var(--secondary-color);
}

.paper-details-meta div {
  display: flex;
  align-items: center;
  gap: 5px;
}

.paper-details-abstract {
  margin-bottom: 30px;
}

.paper-details-abstract h3 {
  font-size: 18px;
  margin-bottom: 10px;
}

.paper-details-content {
  margin-bottom: 30px;
}

.paper-details-content h3 {
  font-size: 18px;
  margin-bottom: 15px;
}

.paper-details-actions {
  display: flex;
  gap: 15px;
  margin-top: 30px;
}

.citation-formats {
  margin-top: 20px;
  padding: 15px;
  border-radius: var(--border-radius);
  font-family: monospace;
  white-space: pre-wrap;
}

.light-mode .citation-formats {
  background-color: #f5f5f5;
}

.dark-mode .citation-formats {
  background-color: #2a2d3a;
}

/* Add these styles at the end of the file */

/* Share Paper Styles */
.share-options {
  margin-top: 20px;
}

.share-link-container {
  display: flex;
  margin-bottom: 15px;
}

.share-link-container input {
  flex: 1;
  padding: 10px;
  border: 1px solid var(--border-light);
  border-radius: var(--border-radius) 0 0 var(--border-radius);
  font-size: 14px;
}

.dark-mode .share-link-container input {
  background-color: #2a2d3a;
  color: var(--body-text-dark);
  border-color: var(--border-dark);
}

.share-link-container button {
  border-radius: 0 var(--border-radius) var(--border-radius) 0;
  padding: 10px 15px;
  margin: 0;
}

.social-share {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.social-share-btn {
  display: flex;
  align-items: center;
  gap: 5px;
  padding: 8px 15px;
  border-radius: var(--border-radius);
  font-size: 14px;
  color: white;
  text-decoration: none;
  transition: opacity var(--transition-speed);
}

.social-share-btn:hover {
  opacity: 0.9;
  color: white;
}

.social-share-btn.twitter {
  background-color: #1da1f2;
}

.social-share-btn.facebook {
  background-color: #4267b2;
}

.social-share-btn.linkedin {
  background-color: #0077b5;
}

/* Highlight search results */
.highlight {
  background-color: rgba(255, 255, 0, 0.3);
  padding: 0 2px;
}

.dark-mode .highlight {
  background-color: rgba(255, 255, 0, 0.2);
}