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

/* Root Variables */
:root {
  /* Colors - optimized for accessibility with better contrast ratios */
  --background-color: #fbfbfb;
  --text-color: #333333;        /* Darker for better readability on light backgrounds */
  --muted-color: #666666;       /* Darker muted text for better contrast */
  --light-gray: #767676;        /* Minimum color that passes WCAG AA on white */
  --border-color: #d0cfcf;
  --accent-color: #0056b3;      /* More vibrant blue for interactive elements */
  --white: #ffffff;

  /* Typography */
  --serif-font: Georgia, "Times New Roman", serif;
  --sans-font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --mono-font: SFMono-Regular, Consolas, "Liberation Mono", Menlo, monospace;
  
  /* Spacing */
  --spacing-1: 0.5rem;
  --spacing-2: 1rem;
  --spacing-3: 1.5rem;
  --spacing-4: 2rem;
  --spacing-5: 3rem;
  --spacing-6: 4rem;
  
  /* Width/Layout */
  --content-width: 42rem;
  --narrow-width: 32rem;
}

/* Base HTML Elements */
html {
  font-size: 18px;
  /* Only apply smooth scrolling when explicitly requested, not on page load */
  scroll-behavior: auto;
}

/* Apply smooth scrolling only for intentional in-page navigation */
html.enable-smooth-scroll {
  scroll-behavior: smooth;
}

body {
  font-family: var(--sans-font);
  background-color: var(--background-color);
  color: var(--text-color);
  line-height: 1.6;
  min-height: 100vh;
}

body > div {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Typography using default element styling */
h1, h2, h3, h4, h5, h6 {
  font-weight: normal;
  line-height: 1.2;
}

/* Header context styling */
header h1 {
  font-size: 4rem;
  letter-spacing: 0.05em;
  color: var(--light-gray);
  line-height: 0.95;
}

/* Main section headers */
main h2 {
  font-size: 1.75rem;
  margin-top: var(--spacing-6);
  margin-bottom: var(--spacing-3);
  text-align: center;
  font-family: var(--serif-font);
}

/* Subsection headers */
section h3 {
  font-size: 1.25rem;
  margin-top: var(--spacing-4);
  margin-bottom: var(--spacing-2);
  font-family: var(--sans-font);
  font-weight: 600;
}

/* Base paragraph styling */
p {
  margin-bottom: var(--spacing-3);
  font-family: var(--sans-font);
  font-size: 1rem;
  line-height: 1.5;
}

/* List styling to match paragraphs */
.publications-list {
  margin-bottom: var(--spacing-3);
  padding-left: 0;
  list-style-position: inside;
}

.publications-list li {
  margin-bottom: var(--spacing-2);
  line-height: 1.5;
}

a {
  color: var(--text-color);
  text-decoration: underline;
  text-underline-offset: 2px;
  transition: color 0.2s ease;
}

a:hover {
  color: var(--accent-color);
  text-decoration: none;
}

em {
  font-style: italic;
  font-family: var(--sans-font);
  font-size: 0.9rem;
  color: var(--muted-color);
  display: block;
  margin-bottom: 0.5rem;
}

/* Header Styles */
#header {
  padding: 0;
}

/* Header styling using semantic selectors */
header > div:first-child {
  margin-bottom: var(--spacing-3);
}

header > div:first-child > div {
  display: flex;
  justify-content: flex-end;
  padding: var(--spacing-2) var(--spacing-4);
}

header nav {
  display: flex;
  gap: var(--spacing-3);
}

header nav a {
  color: var(--muted-color);
  text-decoration: none;
  font-size: 0.9rem;
  transition: color 0.2s ease;
}

header nav a:hover, 
header nav a:focus {
  color: var(--text-color);
}

/* Logo and announcement area */
header [role="banner"] {
  text-align: center;
  padding: var(--spacing-5) var(--spacing-4);
}

header [role="banner"] > a:first-child {
  display: block;
  margin-bottom: var(--spacing-4);
  text-decoration: none;
}

header [role="banner"] > a:nth-child(2) {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-1);
  text-decoration: none;
  transition: opacity 0.2s ease;
}

header [role="banner"] > a:nth-child(2):hover,
header [role="banner"] > a:nth-child(2):focus {
  opacity: 0.8;
}

/* "NEW" pill styling */
header [role="banner"] > a:nth-child(2) > span:first-child {
  background-color: var(--accent-color);
  color: var(--white);
  padding: 0.15rem 0.75rem;
  border-radius: 9999px;
  font-size: 0.7rem;
  font-weight: 500;
}

header [role="banner"] > a:nth-child(2) > span:last-child {
  color: var(--muted-color);
  font-size: 0.9rem;
}

/* Main Content */
#main {
  flex-grow: 1;
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 0 var(--spacing-4) var(--spacing-6) var(--spacing-4);
  width: 100%;
}

.content {
  max-width: 100%;
}

.introduction {
  margin-bottom: var(--spacing-5);
}

section {
  margin-bottom: var(--spacing-5);
}

/* Contact Links */
.contact-links {
  list-style-type: none;
  margin-top: var(--spacing-3);
  display: flex;
  flex-direction: column;
  gap: var(--spacing-2);
}

/* Blog and Projects */
.post, .project {
  margin-bottom: var(--spacing-5);
  padding-bottom: var(--spacing-3);
  border-bottom: 1px solid var(--border-color);
}

.post:last-child, .project:last-child {
  border-bottom: none;
}

.post time, .project time {
  display: block;
  color: var(--muted-color);
  font-size: 0.9rem;
  margin-bottom: var(--spacing-1);
}

.post h3, .project h3 {
  margin-top: 0;
  margin-bottom: var(--spacing-2);
}

/* Project Layout with Preview */
.project-container {
  display: flex;
  flex-direction: row;
  align-items: flex-start;
  gap: var(--spacing-3);
  margin-bottom: var(--spacing-5);
  padding-bottom: var(--spacing-3);
  border-bottom: 1px solid var(--border-color);
  width: 100%;
}

.project-container:last-child {
  border-bottom: none;
}

.project-preview {
  flex: 0 0 300px;
  min-width: 300px;
  max-width: 300px;
  height: 250px;
  border-radius: 8px;
  overflow: hidden;
  border: 1px solid var(--border-color);
  background-color: var(--background-color);
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
}

.project-preview iframe {
  width: 100%;
  height: 100%;
  border: none;
}

/* Medium Article Styling */
.medium-article {
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  padding: 1rem;
  background-color: var(--bg-subtle);
  border-radius: 8px;
}

.medium-article a {
  width: 100%;
  text-align: center;
  font-size: 1.1rem;
  line-height: 1.4;
  text-decoration: none;
  color: var(--text-color);
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.medium-article .article-summary {
  font-size: 0.9rem;
  line-height: 1.4;
  color: var(--text-secondary);
  text-align: center;
  margin: 0;
}



.project-preview img {
  max-width: 100%;
  height: auto;
  object-fit: cover;
}

.project-preview iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  border: none;
}

.project-details {
  flex: 1;
}

.project-details h3 {
  margin-top: 0;
  margin-bottom: var(--spacing-2);
  font-family: var(--sans-font);
  font-weight: 600;
  font-size: 1.2rem;
}

@media (max-width: 768px) {
  .project-container, .social-media-container {
    flex-direction: column;
  }
  
  .project-preview, .twitter-embed-container, .youtube-embed-container {
    width: 100%;
    max-width: 100%;
    min-width: 100%;
    height: 250px;
    flex: 0 0 auto;
    margin-bottom: var(--spacing-2);
  }
  
  .project-details {
    width: 100%;
  }
  
  .youtube-embed-container {
    height: 200px;
  }
}

.subtitle {
  display: block;
  color: var(--muted-color);
  font-size: 1.2rem;
  margin-top: var(--spacing-1);
}

.contact-links li {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--spacing-2) 0;
  border-bottom: 1px solid var(--border-color);
}

.contact-links li:last-child {
  border-bottom: none;
}

.contact-links a {
  font-family: var(--serif-font);
  font-size: 1.1rem;
}

/* Footer */
#footer {
  border-top: 1px solid var(--border-color);
  padding: var(--spacing-4) 0;
  margin-top: var(--spacing-4);
}

.footer-content {
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 0 var(--spacing-4);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  color: var(--muted-color);
  font-size: 0.85rem;
  gap: var(--spacing-1);
}

.footer-first-row,
.footer-second-row {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: var(--spacing-1);
}

.footer-first-row {
  margin-bottom: var(--spacing-1);
}

.footer-separator {
  margin: 0 var(--spacing-1);
}

#footer a {
  color: var(--muted-color);
  text-decoration: none;
  transition: color 0.2s ease;
}

#footer a:hover {
  color: var(--text-color);
}

/* Accessibility */
a:focus, 
button:focus,
input:focus,
select:focus,
textarea:focus,
[tabindex]:focus {
  outline: 2px solid var(--accent-color);
  outline-offset: 2px;
}

/* Focus state for dark mode */
html.dark-theme a:focus, 
html.dark-theme button:focus,
html.dark-theme input:focus,
html.dark-theme select:focus,
html.dark-theme textarea:focus,
html.dark-theme [tabindex]:focus {
  outline-color: var(--light-gray);
}

/* Visually hidden but available to screen readers */
.screen-reader-text,
[aria-hidden="true"] {
  border: 0;
  clip: rect(1px, 1px, 1px, 1px);
  clip-path: inset(50%);
  height: 1px;
  margin: -1px;
  overflow: hidden;
  padding: 0;
  position: absolute !important;
  width: 1px;
  word-wrap: normal !important;
}

/* Skip to content link - improved accessibility */
.skip-link, a[href="#main"] {
  position: absolute;
  top: -100px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--accent-color);
  color: var(--background-color);
  font-weight: 600;
  padding: var(--spacing-2) var(--spacing-3);
  border-radius: 0 0 8px 8px;
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.2);
  z-index: 1000;
  transition: top 0.3s ease;
  text-decoration: none;
  font-size: 1rem;
  display: inline-block;
  text-align: center;
  width: auto;
}

.skip-link, a[href="#main"]:focus {
  top: 0;
  outline: 2px solid var(--text-color);
  outline-offset: 2px;
}

/* Skip link in dark mode */
html.dark-theme .skip-link, html.dark-theme a[href="#main"] {
  background: var(--accent-color);
  color: var(--background-color);
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.5);
}

/* Skip link hover and active states */
.skip-link, a[href="#main"]:hover,
.skip-link, a[href="#main"]:active {
  background: var(--text-color);
  color: var(--background-color);
}

/* Social Media Embed Layout */
.social-media-container {
  display: flex;
  flex-direction: row;
  flex-wrap: nowrap;
  gap: var(--spacing-3);
  justify-content: center;
  align-items: center;
  margin: var(--spacing-4) auto;
  width: 100%;
  max-width: 650px;
}

/* Twitter Embed */
.twitter-embed-container {
  flex: 0 0 300px;
  min-width: 300px;
  max-width: 300px;
  height: 250px;
  overflow: hidden;
  background-color: var(--background-color);
  border-radius: 12px;
  border: 1px solid var(--border-color);
  position: relative;
}

/* Twitter embed styling */
.twitter-embed-container .twitter-tweet {
  margin: 0 auto !important;
  width: 100% !important;
  max-width: 100% !important;
}

/* Fix Twitter widget overflow */
.twitter-embed-container .twitter-tweet iframe {
  width: 100% !important;
  height: 250px !important;
  max-width: 100% !important;
}

/* YouTube Embed */
.youtube-embed-container {
  flex: 0 0 300px;
  min-width: 300px;
  max-width: 300px;
  height: 250px;
  border-radius: 12px;
  overflow: hidden;
  position: relative;
  border: 1px solid var(--border-color);
}

.youtube-embed-container iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  border: none;
}

/* Responsive Design */
@media (max-width: 768px) {
  :root {
    --content-width: 100%;
  }
  
  html {
    font-size: 16px;
  }
  
  h1 {
    font-size: 3rem;
  }
  
  .nav-group {
    padding: var(--spacing-2);
  }
  
  .logo-container {
    padding: var(--spacing-4) var(--spacing-2);
  }
  
  #main {
    padding: 0 var(--spacing-2) var(--spacing-4) var(--spacing-2);
  }

  .footer-content {
    padding: 0 var(--spacing-2);
  }
}

@media (max-width: 480px) {
  html {
    font-size: 15px;
  }
  
  h1 {
    font-size: 2.5rem;
  }
  
  .top-nav {
    gap: var(--spacing-2);
  }
  
  .home-announcement {
    flex-direction: column;
    gap: var(--spacing-1);
  }
  
  .publications-list {
    padding-right: var(--spacing-1);
  }
  
  .publications-list li {
    word-wrap: break-word;
  }
}

/* Print Styles */
@media print {
  body {
    background: white;
    color: black;
  }
  
  #main {
    max-width: 100%;
  }
  
  a {
    color: black;
    text-decoration: underline;
  }
  
  #header, #footer {
    display: none;
  }
}

/* Dark Mode Support - apply when system prefers dark and no manual override */
@media (prefers-color-scheme: dark) {
  :root {
    --background-color: #121212;
    --text-color: #f8f9fa;
    --muted-color: #bbbbbb;
    --light-gray: #a0a0a0;
    --border-color: #2d2d2d;
    --accent-color: #4dabf7;
    --white: #121212;
  }
  
  .pill {
    background-color: var(--accent-color);
    color: var(--background-color);
  }
}

/* Manual dark theme toggle - applied when user explicitly toggles */
html.dark-theme {
  --background-color: #121212;
  --text-color: #f8f9fa;
  --muted-color: #bbbbbb;
  --light-gray: #a0a0a0;
  --border-color: #2d2d2d;
  --accent-color: #4dabf7;
  --white: #121212;
}

/* Manual light theme - explicitly set light colors when toggled */
html.light-theme {
  --background-color: #fbfbfb;
  --text-color: #333333;
  --muted-color: #666666;
  --light-gray: #767676;
  --border-color: #d0cfcf;
  --accent-color: #0056b3;
  --white: #ffffff;
}

html.dark-theme .pill {
  background-color: var(--accent-color);
  color: var(--background-color);
}

/* Theme toggle button styles */
.theme-toggle-button {
  font-family: var(--sans-font);
  font-size: 0.85rem;
  color: var(--muted-color);
  background: none;
  border: none;
  padding: 0;
  cursor: pointer;
  text-decoration: underline;
  text-underline-offset: 2px;
}

.theme-toggle-button:hover {
  color: var(--text-color);
}

.theme-toggle-button:focus {
  outline: 2px solid var(--accent-color);
  outline-offset: 2px;
}

/* Skip to content link */
.skip-to-content {
  position: absolute;
  left: 50%;
  transform: translateX(-50%) translateY(-100%);
  padding: var(--spacing-1) var(--spacing-2);
  background: var(--accent-color);
  color: var(--white);
  z-index: 1000;
  transition: transform 0.3s;
}

.skip-to-content:focus {
  transform: translateX(-50%) translateY(0);
  outline: none;
}