/* Base Variables */
:root {
  /* Signal Flow Palette - Light Mode (Default) */
  --clr-background-primary: #FFFFFF;
  --clr-background-secondary: #F0F2F5;
  --clr-text-primary: #212529;
  --clr-text-secondary: #6C757D;
  --clr-text-headings: #1A1F23;
  --clr-accent-primary: #4A90E2;
  --clr-accent-secondary: #357ABD;
  --clr-border-primary: #DEE2E6;
  --clr-shadow-color: rgba(0, 0, 0, 0.075);
  /* Non-color variables from original theme - kept */
  --space-xs: .5rem;
  --space-s: 1rem;
  --space-m: 1.5rem;
  --space-l: 2.5rem;
  --space-xl: 4rem;

  --transition-standard: 0.3s ease;
  --shadow-standard: 0 4px 6px var(--clr-shadow-color); /* Updated to use new shadow variable */
  --border-radius: 8px;

  --font-primary: 'Brandon Grotesque', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
  --font-weight-light: 300;
  --font-weight-regular: 400; 
  --font-weight-medium: 500;
  --font-weight-bold: 700;
  --font-weight-black: 900;
}

html[data-theme="dark"] {
  /* Signal Flow Palette - Dark Mode */
  --clr-background-primary: #121212;
  --clr-background-secondary: #1E1E1E;
  --clr-text-primary: #E0E0E0;
  --clr-text-secondary: #A0A0A0;
  --clr-text-headings: #F5F5F5;
  --clr-accent-primary: #5E9BEF;
  --clr-accent-secondary: #7BAAF0;
  --clr-border-primary: #333333;
  --clr-shadow-color: rgba(0, 0, 0, 0.3);
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  scroll-padding-top: 70px; /* Account for sticky header */
  background-color: var(--clr-background-primary);
  color: var(--clr-text-primary);
  transition: background-color var(--transition-standard), color var(--transition-standard);
}

body {
  font-family: var(--font-primary);
  line-height: 1.6;
  /* color is inherited from html */
  /* background-color is inherited from html */
  font-weight: var(--font-weight-light); /* Default text weight is light */
}

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

a {
  color: var(--clr-accent-primary);
  text-decoration: none;
  transition: color var(--transition-standard);
}

a:hover, a:focus {
  color: var(--clr-accent-secondary);
  text-decoration: underline;
}

ul {
  list-style: none;
}

/* Base Typography */
h1, h2, h3, h4, h5, h6 {
  line-height: 1.2;
  margin-bottom: var(--space-s);
  color: var(--clr-text-headings);
}

/* Primary headings */
h1, h2 {
  font-weight: var(--font-weight-medium);
  text-align: center;
}

/* Secondary headings */
h3, h4, h5, h6 {
  font-weight: var(--font-weight-regular);
}

/* Specific heading sizes */
h1 {
  font-size: 2.5rem;
}

h2 {
  font-size: 2rem;
  margin-bottom: var(--space-l);
}

h3 {
  font-size: 1.5rem;
  margin-bottom: var(--space-m);
  text-align: center;
}

/* Override centering for company names in experience section */
.company-name {
  text-align: left;
  margin-bottom: var(--space-s); /* Reduced from default h3 margin */
}

/* Style degree names to match company names */
.degree-name {
  text-align: left;
  margin-bottom: var(--space-xs); /* Small gap between degree and institution */
}

/* Style for inline position dates */
.position-date {
  font-weight: var(--font-weight-light);
  color: var(--clr-text-secondary);
  font-size: 0.9em;
}

/* Add spacing around the bullet separator */
.bullet-separator {
  margin: 0 0.25em;
  color: var(--clr-text-secondary);
}

/* Style for education dates and GPA to match experience section */
.education-date,
.education-gpa {
  font-weight: var(--font-weight-light);
  color: var(--clr-text-secondary);
  font-size: 0.9em;
}

#about h3 {
  margin-bottom: var(--space-xl);
}

p {
  margin-bottom: var(--space-s);
}

.container {
  width: 90%;
  max-width: 1200px;
  margin: 0 auto;
  padding: var(--space-s);
}

/* Section Styles */
.section {
  padding: var(--space-xl) 0;
  padding-top: calc(var(--space-xl) + 5px); /* Minimal additional padding */
  margin-top: 0; /* Remove negative margin */
  border-top: 5px solid transparent; /* Add invisible border for spacing */
  position: relative; /* Ensure proper stacking context */
  opacity: 1; /* Always show backgrounds */
  background-color: var(--clr-background-secondary); /* Default section background */
  transition: background-color var(--transition-standard);
}

/* Make specific sections use primary background if they should be plain */
#experience,
#education,
#interests {
  background-color: var(--clr-background-primary);
}

/* For pre-loading sections when hash is in URL */
body.hash-navigation .section {
  opacity: 0;
  transition: opacity 0.1s ease-out;
}

body.hash-navigation .section.bg-visible {
  opacity: 1;
}

/* Inner content wrapper for fade-in effect */
.section > .container {
  opacity: 1; /* Changed from 0 to 1 to allow individual elements to control their own animations */
  transform: none; /* Removed transform from container */
  transition: none; /* Removed transition from container */
}

.section.visible > .container {
  opacity: 1;
  transform: none;
}

/* NEW: Individual element animations */
.fade-in-element {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease-out, transform 0.6s ease-out;
}

/* Staggered animation timing for different element types */
h2.fade-in-element {
  transition-delay: 0s;
}

h3.fade-in-element {
  transition-delay: 0.1s;
}

.about-grid.fade-in-element,
.experience-item.fade-in-element,
.project-card.fade-in-element,
.education-row.fade-in-element,
.skills-column.fade-in-element,
#contact-form.fade-in-element,
.research.fade-in-element {
  transition-delay: 0.2s;
}

/* Children of timeline items should stagger */
.experience-item:nth-child(2).fade-in-element {
  transition-delay: 0.25s;
}

.experience-item:nth-child(3).fade-in-element {
  transition-delay: 0.3s;
}

.experience-item:nth-child(4).fade-in-element {
  transition-delay: 0.35s;
}

.experience-item:nth-child(5).fade-in-element {
  transition-delay: 0.4s;
}

/* Children of project cards should stagger */
.project-card:nth-child(2).fade-in-element {
  transition-delay: 0.25s;
}

.project-card:nth-child(3).fade-in-element {
  transition-delay: 0.3s;
}

/* Reset all delays when element becomes visible */
.fade-in-element.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Section ID targets have a pseudo element to provide scroll target padding */
.section::before {
  content: '';
  display: block;
  height: 70px; /* Same as header height */
  margin-top: -70px; /* Negative margin of the same value */
  visibility: hidden;
  pointer-events: none;
}

/* Section Colors & Text Color Overrides where needed */
/* #about, #projects, #education, #skills, #contact previously had specific bg colors.
   They will now use --clr-background-secondary by default from .section or can be overridden if a unique bg is still desired.
   Text color within these sections needs to ensure contrast against their backgrounds.
   If a section has a darker background (even in light mode), its text might need to be light.
*/

/* Example for a section that might retain a distinct background and need text color adjustment */
/* #projects {
  background-color: var(--clr-accent-primary); 
  color: var(--clr-background-primary); 
} 
#projects h2, #projects h3, #projects h4 a, #projects p, #projects .meta {
  color: var(--clr-background-primary);
}
*/

/* Defaulting all section text to match page text color for now */
/* If specific sections get darker backgrounds later, this will need adjustment */
.section h1,
.section h2,
.section h3,
.section h4,
.section h5,
.section h6 {
  color: var(--clr-text-headings);
}

.section p, .section div, .section li {
  /* Standard text within sections */
  /* color: var(--clr-text-primary); */ /* This would be inherited, but good to be explicit if needed */
}

/* Header & Navigation */
header {
  position: sticky;
  top: 0;
  background-color: var(--clr-background-secondary); /* Updated: Use secondary background */
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  z-index: 1000;
  box-shadow: var(--shadow-standard);
  transition: background-color var(--transition-standard);
}

header .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 70px;
  padding-left: var(--space-xs);
  padding-right: var(--space-xs);
}

.logo {
  font-weight: var(--font-weight-light);
  font-size: 1.1rem;
  color: var(--clr-text-headings); /* Updated: Text on lighter header background */
  text-decoration: none;
  white-space: nowrap;
  transition: color 0.2s ease;
}

.logo:hover {
  color: var(--clr-accent-primary); /* Accent for hover */
  text-decoration: none;
}

.desktop-nav {
  display: none;
  white-space: nowrap;
  align-items: center;
}

.desktop-nav li {
  display: inline-block;
  margin-left: 2px;
  display: flex;
  align-items: center;
}

.desktop-nav a {
  color: var(--clr-text-primary); /* Updated: Text on lighter header background */
  font-weight: var(--font-weight-light);
  padding: var(--space-xs) 4px;
  font-size: 0.9rem;
  transition: color 0.2s ease;
  line-height: 1;
}

.desktop-nav a:hover {
  color: var(--clr-accent-primary);
  text-decoration: none;
}

/* Only show focus styles when using keyboard navigation */
.desktop-nav a:focus-visible {
  color: var(--clr-accent-primary);
  text-decoration: none;
  outline: 2px solid var(--clr-accent-primary);
  outline-offset: 2px;
}

/* Remove default focus styles but keep accent color for clicked state */
.desktop-nav a:focus:not(:focus-visible) {
  outline: none;
  color: var(--clr-accent-primary);
}

.desktop-nav a[target="_blank"]:hover {
  color: var(--clr-accent-secondary); /* Using secondary accent for external link differentiation */
}

/* Apply the same focus behavior to the logo link */
.logo:focus-visible {
  color: var(--clr-accent-primary);
  outline: 2px solid var(--clr-accent-primary);
  outline-offset: 2px;
}

.logo:focus:not(:focus-visible) {
  outline: none;
  color: var(--clr-accent-primary);
}

/* Remove the arrow indicators */
.desktop-nav a[target="_blank"]::after {
  content: "";
}

/* Mobile Navigation */
.mobile-nav {
  position: relative;
}

.mobile-nav summary {
  list-style: none;
  cursor: pointer;
  width: 30px;
  height: 24px;
  position: relative;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.mobile-nav summary::-webkit-details-marker {
  display: none;
}

.mobile-nav summary span {
  display: block;
  width: 100%;
  height: 3px;
  background-color: var(--clr-text-headings); /* Updated: Hamburger icon lines on lighter header */
  transition: transform 0.3s ease;
}

.mobile-nav[open] summary span:nth-child(1) {
  transform: translateY(10px) rotate(45deg);
}

.mobile-nav[open] summary span:nth-child(2) {
  opacity: 0;
}

.mobile-nav[open] summary span:nth-child(3) {
  transform: translateY(-10px) rotate(-45deg);
}

.mobile-nav ul {
  position: absolute;
  top: 100%;
  right: 0;
  background-color: var(--clr-background-secondary); /* Updated: Match header background */
  box-shadow: var(--shadow-standard);
  border-radius: var(--border-radius);
  width: 200px;
  padding: var(--space-s);
  margin-top: var(--space-xs);
}

.mobile-nav li {
  margin-bottom: var(--space-xs);
}

.mobile-nav a {
  display: block;
  padding: var(--space-xs);
  color: var(--clr-text-primary); /* Updated: Text on lighter menu background */
  transition: color 0.2s ease;
}

.mobile-nav a:hover {
  color: var(--clr-accent-primary);
}

/* Mobile nav focus styles */
.mobile-nav a:focus-visible {
  color: var(--clr-accent-primary);
  outline: 2px solid var(--clr-accent-primary);
  outline-offset: 2px;
}

.mobile-nav a:focus:not(:focus-visible) {
  outline: none;
  color: var(--clr-accent-primary);
}

.mobile-nav a[target="_blank"]:hover {
  color: var(--clr-accent-secondary);
}

.mobile-nav a[target="_blank"]::after {
  content: "";
}

/* Hero Section */
.hero {
  position: relative;
  height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--clr-background-primary);
  text-align: center;
  /* overflow: hidden; */
  /* z-index: 1; */
  margin-top: 0; /* Reset margin that applies to other sections */
  padding-top: 0; /* Reset padding that applies to other sections */
}

.hero::before {
  display: none; /* Remove the pseudo-element used for scroll anchoring in other sections */
}

.hero-bg {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100vh; /* Cover viewport height for parallax background */
  z-index: -1;
  will-change: transform; /* Optimize for animations */
}

.hero-bg img, .hero-bg video {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transform: translateZ(0); /* Hardware acceleration */
}

/* Hero Canvas Animation */
#hero-code-canvas {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: -1;
}

.hero-content {
  position: relative;
  top: -40px; /* Move hero text slightly above center */
  max-width: 800px;
  padding: var(--space-m);
  animation: fadeUp 0.6s ease-out forwards;
  text-shadow: 0px 2px 6px rgba(0, 0, 0, 0.25); /* Stronger shadow for better contrast on light background */
}

.hero h1 {
  color: var(--clr-text-headings); /* Updated: White text for hero on image */
  font-size: 4rem;
  margin-bottom: var(--space-s);
  font-weight: var(--font-weight-regular);
}

.hero p {
  color: var(--clr-text-primary); /* Added: Explicit color for hero paragraph */
  font-size: 1.5rem;
  margin-bottom: var(--space-s);
}

.hero .hero-tagline {
  margin-bottom: var(--space-s);
}

/* About Section */
.about-grid {
  display: flex;
  flex-direction: column;
  gap: var(--space-l);
  max-width: 900px;
  margin: 0 auto;
}

.about-image {
  display: flex;
  justify-content: center;
}

.about-image img {
  border-radius: 12px;
  width: 350px;
  height: auto;
  object-fit: cover;
  border: 5px solid var(--clr-background-primary); /* Border around image */
  box-shadow: 0 8px 15px var(--clr-shadow-color);
}

.about-content {
  text-align: left;
  max-width: 800px;
  margin: 0 auto;
}

.about-content p {
  margin-bottom: var(--space-m);
  text-align: justify;
  line-height: 1.8;
}

.about-content p:last-child {
  margin-bottom: 0;
}

/* Timeline Container - New design with all content on the right */
.timeline-container {
  position: relative;
  margin: 40px auto;
  max-width: 800px;
  --timeline-line-offset: 50px;
  --timeline-content-padding-start: 70px;
}

/* Vertical connecting line */
.timeline-container::before {
  content: '';
  position: absolute;
  top: 0;
  bottom: 0;
  left: var(--timeline-line-offset);
  width: 1px;
  background-color: var(--clr-border-primary); /* Timeline line color */
  transform: translateX(-50%);
}

/* Experience Item */
.experience-item {
  position: relative;
  margin-bottom: 40px;
  padding-bottom: 0;
}

.experience-item:last-child {
  margin-bottom: 0;
}

.experience-content {
  padding-left: var(--timeline-content-padding-start);
  position: relative;
}

.experience-content h4 {
  margin-bottom: 8px;
  color: var(--clr-text-headings); /* Experience title color */
  font-weight: var(--font-weight-medium);
  font-size: 1.2rem;
  text-align: left;
  position: relative;
}

/* All styles related to the timeline dot have been removed. */

.experience-date {
  margin-bottom: 12px;
}

.experience-date span {
  display: inline-block;
  font-weight: var(--font-weight-light);
  color: var(--clr-text-secondary); /* Date color */
  font-size: 0.9rem;
}

.experience-content p {
  color: var(--clr-text-primary); /* Experience description text */
  line-height: 1.6;
}

@media (max-width: 767px) {
  .timeline-container {
    --timeline-line-offset: 35px;
    --timeline-content-padding-start: 55px;
  }
  /* Vertical line will automatically use the updated custom properties */
}

/* Old timeline selectors removed as they are no longer applicable. */

/* Projects Section */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--space-m);
}

/* Media queries for projects grid */
@media (min-width: 768px) {
  .projects-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

.project-card {
  background-color: var(--clr-background-primary); /* Card background */
  border-radius: var(--border-radius);
  padding: var(--space-m);
  box-shadow: var(--shadow-standard);
  border: 1px solid var(--clr-border-primary);
  cursor: pointer;
  /* Override fade-in-element transition for instant hover response */
  transition: transform 0.1s ease, box-shadow 0.1s ease, border-color 0.1s ease !important;
}

.project-card:hover {
  transform: scale(1.02);
  box-shadow: 0 10px 20px var(--clr-shadow-color); /* Enhanced shadow on hover */
  background-color: var(--clr-background-primary); /* Keep card background same on hover */
  border-color: var(--clr-accent-primary);
}

.project-card h4 {
  border-bottom: 2px solid var(--clr-border-primary);
  padding-bottom: var(--space-xs);
  margin-bottom: var(--space-s);
  text-align: left;
  position: relative;
}

.project-card h4 a {
  color: var(--clr-text-headings);
  text-decoration: none;
  transition: color 0.2s ease;
}

/* Animated underline for the border separator line */
.project-card h4::after {
  content: '';
  position: absolute;
  bottom: -2px; /* Position to cover the border line */
  left: 0;
  width: 100%;
  height: 2px;
  background-color: var(--clr-accent-primary);
  transform: scaleX(0);
  transform-origin: right;
  transition: transform 0.3s ease;
}

.project-card:hover h4::after {
  transform: scaleX(1);
  transform-origin: left;
}

.project-card:hover h4 a {
  color: var(--clr-accent-primary); /* Turn text blue on card hover */
}

.project-demo {
  margin: var(--space-s) 0;
}

.project-demo a {
  display: inline-block;
  background-color: var(--clr-accent-primary);
  color: var(--clr-background-primary); /* Text on accent button */
  padding: 6px 12px;
  border-radius: 4px;
  font-size: 0.9rem;
  transition: background-color 0.2s ease, color 0.2s ease;
}

.project-demo a:hover {
  background-color: var(--clr-accent-secondary);
  color: var(--clr-background-primary);
  text-decoration: none;
}

.project-card .meta {
  display: flex;
  gap: var(--space-s);
  margin-top: var(--space-s);
  color: var(--clr-text-secondary); /* Meta text color */
  font-size: 0.875rem;
}

.project-card .meta li {
  display: flex;
  align-items: center;
}

/* Education Section */
.education-grid {
  display: flex;
  flex-direction: column;
  gap: var(--space-l);
  margin-bottom: var(--space-l);
  width: 100%;
  max-width: 800px;
  margin-left: auto;
  margin-right: auto;
}

.education-row {
  display: flex;
  align-items: flex-start;
  width: 100%;
  position: relative;
}

.education-row::after {
  content: '';
  position: absolute;
  top: 0;
  bottom: 0;
  left: 50%;
  width: 1px;
  background-color: var(--clr-border-primary); /* Education timeline color */
  transform: translateX(-50%);
}

.education-left {
  flex: 1;
  text-align: right;
  padding-right: var(--space-m);
  display: flex;
  flex-direction: column;
  gap: 0.25em;
  font-size: 1.15rem;
  color: var(--clr-text-primary); /* Text color for education section */
}

.education-left > div {
  text-align: right;
}

.education-right {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 0.25em;
  text-align: left;
  padding-left: var(--space-m);
}

.education-right h3,
.education-right h4 {
  line-height: 1.4;
}

.education-right h4 {
  margin-bottom: 0.25em;
}

@media (max-width: 700px) {
  .education-grid {
    gap: 0;
  }

  .education-row {
    flex-direction: column;
    gap: var(--space-xs);
    align-items: center;
    padding-bottom: var(--space-s);
    margin-bottom: var(--space-xs);
    border-bottom: 1px solid var(--clr-border-primary); /* Horizontal line separating each complete education entry */
  }

  .education-row:last-child {
    border-bottom: none; /* Remove border from the last education entry */
    margin-bottom: 0;
    padding-bottom: 0;
  }

  .education-row::after {
    content: none; /* Remove the vertical line */
  }

  /* Reorder: degree/institution first (larger text) */
  .education-right {
    flex: 0 0 auto;
    width: 100%;
    text-align: center;
    padding-left: 0;
    border-top: none;
    padding-top: var(--space-s);
    margin-top: var(--space-xs);
    align-items: center;
    order: 1; /* Show first */
  }

  .education-right h3 {
    font-size: 1.2rem;
    font-weight: var(--font-weight-medium);
  }

  /* Date range and GPA second (smaller text) */
  .education-left {
    flex: 0 0 auto;
    width: 100%;
    font-size: 0.95rem;
    color: var(--clr-text-secondary);
    text-align: center;
    padding-right: 0;
    align-items: center;
    order: 2; /* Show second */
  }

  .education-left > div {
    text-align: center;
  }
}

/* Skills Section */
.skills-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-l);
}

.skills-column {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  min-width: 0;
}

.skills-column h3 {
  margin-bottom: var(--space-s);
  text-align: center;
}

.skill-icon {
  display: flex;
  justify-content: center;
  align-items: center;
  margin-bottom: var(--space-s);
}

.skill-icon svg {
  color: var(--clr-accent-primary);
  width: 48px;
  height: 48px;
  transition: color var(--transition-standard);
}

.skill-tags {
  width: 100%;
  column-gap: var(--space-m);
  text-align: left;
}

.skill-tags.two-columns {
  columns: 2;
}

.skill-tags.three-columns {
  columns: 3;
}

.skill-tag {
  display: list-item; /* Treat as a list item to ensure new line and bullet */
  list-style-type: disc; /* Ensure bullet is visible */
  color: var(--clr-text-primary);
  font-size: 0.95rem;
  margin-bottom: 0.5em;
  margin-left: 1.5em; /* Indentation for the bullet */
  break-inside: avoid; /* Prevent items from breaking across columns */
}

/* Custom bullet style is not needed as list-style-type handles it */
.skill-tag::before {
  content: none;
}

/* Media query for tablet and desktop */
@media (min-width: 768px) {
  .skills-grid {
    grid-template-columns: repeat(3, 1fr);
  }

  /* Adjust degree name font size for larger screens */
  .degree-name {
    font-size: 1.4rem; 
  }

  /* Adjust minor degree info font size for larger screens */
  .minor-degree-info {
    font-size: 1.2rem; 
  }
}

@media (max-width: 700px) {
  /* Adjust minor degree info font size for small screens */
  .minor-degree-info {
    font-size: 1.2rem; /* Between h3 (1.2rem) and h4 (1rem) */
  }
}



/* Contact Section */
#contact-form {
  max-width: 600px;
  margin: 0 auto;
}

#contact-form label {
  display: block;
  margin-bottom: var(--space-s);
}

#contact-form input,
#contact-form textarea {
  display: block;
  width: 100%;
  padding: var(--space-s);
  margin-bottom: var(--space-m);
  border-radius: var(--border-radius);
  border: 1px solid var(--clr-border-primary);
  background-color: var(--clr-background-primary);
  color: var(--clr-text-primary);
}

#contact-form button {
  background-color: var(--clr-accent-primary);
  color: var(--clr-background-primary); /* Text on accent button */
  border: none;
  padding: var(--space-s) var(--space-m);
  border-radius: var(--border-radius);
  cursor: pointer;
  transition: background-color var(--transition-standard);
}

#contact-form button:hover {
  background-color: var(--clr-accent-secondary);
}

/* Back to Top Button */
.to-top {
  position: fixed;
  bottom: 20px;
  right: 20px;
  width: 50px;
  height: 50px;
  background-color: var(--clr-accent-primary);
  color: var(--clr-background-primary); /* Icon color on accent button */
  border-radius: 50%;
  border: none;
  font-size: 1.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s ease, background-color 0.3s ease;
  z-index: 999;
}

.to-top.visible {
  opacity: 1;
  pointer-events: all;
}

.to-top:hover {
  background-color: var(--clr-accent-secondary);
}

.to-top:focus {
  outline: 2px solid var(--clr-accent-secondary);
}

/* Footer */
footer {
  background-color: var(--clr-background-secondary); /* Updated: Dark footer background */
  padding: var(--space-l) 0;
  text-align: center;
  color: var(--clr-text-primary); /* Updated: Light text on dark footer */
}

footer .container {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.social {
  display: flex;
  flex-wrap: nowrap;
  justify-content: center;
  margin-bottom: var(--space-m);
  overflow-x: auto; /* Allow scrolling if content overflows */
  scrollbar-width: none; /* Firefox: hide scrollbar */
}

/* Chrome, Safari, Opera: hide scrollbar */
.social::-webkit-scrollbar {
  display: none;
}

.social a {
  color: var(--clr-text-primary);
  padding: var(--space-xs);
  transition: color var(--transition-standard);
  display: flex;
  align-items: center;
  justify-content: center;
}

.social a:hover {
  color: var(--clr-accent-primary);
}

.social-icon {
  width: 24px;
  height: 24px;
  fill: currentColor;
  transition: fill var(--transition-standard);
}

/* Increase spacing and size on larger screens */
@media (min-width: 768px) {
  .social-icon {
    width: 28px;
    height: 28px;
  }
}

/* Optional: Add a subtle hover effect */
.social a:hover .social-icon {
  transform: translateY(-2px);
  transition: transform 0.2s ease;
}

/* Animations */
@keyframes fadeUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Media Queries */
@media (min-width: 768px) {
  .desktop-nav {
    display: flex;
    align-items: center;
  }

  .mobile-nav {
    display: none;
  }

  /* More compact navigation on medium screens */
  .desktop-nav a {
    padding: var(--space-xs) 3px;
    font-size: 0.85rem;
  }
  
  .logo {
  font-size: 1rem;
  }

  .about-grid {
    display: flex;
    flex-direction: row;
    align-items: stretch;
    position: relative;
  }
  
  .about-image {
    flex: 0 0 auto;
    position: absolute;
    top: 0;
    left: 0;
    bottom: 0;
    width: 280px;
    display: flex;
    align-items: center;
  }
  
  .about-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
  }
  
  .about-content {
    flex: 1;
    margin-left: 320px;
    padding-left: 0;
  }

  /* Timeline styles are now handled by the new timeline-container design */

  .skills-grid {
    grid-template-columns: repeat(3, 1fr);
  }


}

@media (min-width: 1024px) {
  /* Slightly larger spacing on larger screens */
  .desktop-nav a {
    padding: var(--space-xs) 4px;
    font-size: 0.9rem;
  }
  
  .logo {
    font-size: 1.1rem;
  }
  
  h1 {
    font-size: 3.5rem; /* Increased base h1 size */
  }

  .hero h1 {
    font-size: 4.5rem;
  }

  .hero p {
    font-size: 1.75rem;
  }
}

@media (min-width: 1280px) {
  /* More comfortable spacing on extra large screens */
  .desktop-nav a {
    padding: var(--space-xs) 6px;
    font-size: 0.95rem;
  }
  
  .logo {
    font-size: 1.2rem;
  }
}

/* Reduced Motion */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }

  .section {
    transform: none;
    opacity: 1;
  }

  .project-card:hover {
    transform: none;
  }
}



.research {
  margin-top: var(--space-xl); /* Increased spacing for the Research section */
  text-align: center;
}

.research a {
  color: var(--clr-accent-primary);
  text-decoration: underline;
  transition: color var(--transition-standard);
}

.research a:hover, .research a:focus {
  color: var(--clr-accent-secondary);
  text-decoration: underline;
}

#research-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-xs);
}

/* Adjust specific headings to maintain proper spacing in content blocks */
.project-card h4, .skills-column h3 {
  margin-bottom: var(--space-s);
}

/* Section-specific spacing adjustments */
.section h2 + h3 {
  margin-top: calc(-1 * var(--space-m));
  margin-bottom: var(--space-l);
  font-size: 1rem; /* Make it smaller */
  color: var(--clr-text-secondary); /* Date color */
  font-weight: var(--font-weight-light); /* Make it thinner */
}

@media (max-width: 767px) {
  .about-image img {
    width: 250px;
    max-width: 100%;
    margin-bottom: var(--space-m);
  }
  
  .about-content {
    padding: 0 var(--space-s);
  }
}

/* Interactive Demo */
.interactive-demo-container {
  margin-top: var(--space-xl);
  padding: var(--space-m);
  background: var(--clr-background-secondary);
  border-radius: var(--border-radius);
}

.interactive-demo-container h3 {
  margin-bottom: var(--space-m);
  text-align: center;
    color: var(--clr-text-headings);
  }

.interactive-demo-container h3 a {
  color: var(--clr-text-headings);
  text-decoration: none;
  transition: color 0.2s ease;
  position: relative;
}

.interactive-demo-container h3 a:hover {
  color: var(--clr-accent-primary);
}

.interactive-demo-container h3 a::after {
  content: '';
  position: absolute;
  bottom: -3px;
  left: 0;
  width: 100%;
  height: 2px;
    background-color: var(--clr-accent-primary);
  transform: scaleX(0);
  transform-origin: right;
  transition: transform 0.3s ease;
}

.interactive-demo-container h3 a:hover::after {
  transform: scaleX(1);
  transform-origin: left;
}

.interactive-demo {
  width: 100%;
  min-height: 600px;
  position: relative;
  overflow: hidden;
  border-radius: var(--border-radius);
}

.interactive-demo gradio-app {
  display: block;
  width: 100%;
  height: 100%;
  min-height: 600px;
  border: none;
}

/* Fallback for browsers that don't support web components */
.interactive-demo iframe {
  width: 100%;
  height: 600px;
  border: none;
  border-radius: var(--border-radius);
}

/* Media queries for smaller screens */
@media (max-width: 768px) {
  .interactive-demo {
    min-height: 500px;
  }
  
  .interactive-demo gradio-app,
  .interactive-demo iframe {
    min-height: 500px;
  }
}

@media (max-width: 480px) {
  .interactive-demo {
    min-height: 400px;
  }
  
  .interactive-demo gradio-app,
  .interactive-demo iframe {
    min-height: 400px;
  }
}

/* === Timeline Markers for Professional Experience === */

/* This assumes your .timeline-container has position: relative and padding-left (e.g., 30px)
   and its ::before pseudo-element (or similar) creates the vertical timeline bar
   (e.g., at left: 15px within that padding).
   If your setup is different, the 'left' value for the circle will need adjustment. */

.experience-item {
  position: relative; /* Ensures ::before is positioned relative to this item */
}

.experience-item::before {
  content: '';
  position: absolute;
  width: 16px;  /* Total diameter of the marker (including border). The background-colored area is 10px. */
  height: 16px; /* Total diameter of the marker (including border). The background-colored area is 10px. */
  background-color: var(--clr-accent-primary); /* Color of the circle marker. */
  border: 3px solid var(--clr-background-primary);  /* Border color matches the section's background for 'punch-out' effect */
  border-radius: 50%;    /* Makes it a circle */
  box-sizing: border-box; /* Includes border in the element's total width and height */

  /* Vertical alignment:
     'top: 0.7em' attempts to align the circle near the vertical center of the first line of text (e.g., your <h4> title).
     You may need to fine-tune this value (e.g., to 0.6em, 10px, etc.) for perfect alignment with your font and line heights. */
  top: 0.2em; /* Adjusted slightly for a potentially larger marker */

  /* Horizontal positioning:
     This centers the 16px diameter circle marker on the timeline.
     The timeline's position is defined by var(--timeline-line-offset) in .timeline-container.
     The circle's radius is 8px (16px total diameter / 2).
     So, left = var(--timeline-line-offset) - 8px.
     This works responsively as --timeline-line-offset changes for smaller screens.
  */
  left: calc(var(--timeline-line-offset) - 8px);
  z-index: 1;  /* Places the circle marker above the timeline line. */
}

/* Theme Toggle Button */
.theme-toggle-item {
  display: flex;
  align-items: center;
  height: 100%;
}

#theme-toggle {
  background: none;
  border: none;
  color: var(--clr-text-headings); /* Updated: Icon color to match new nav links color */
  cursor: pointer;
  padding: var(--space-xs) 6px; /* Similar padding to nav links */
  margin-left: 2px; /* Consistent with other nav items */
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--border-radius);
  transition: color 0.2s ease, background-color 0.2s ease;
  line-height: 1;
}

#theme-toggle:hover {
  color: var(--clr-accent-primary); /* Matches nav link hover */
}

#theme-toggle:focus-visible {
  color: var(--clr-accent-primary);
    outline: 2px solid var(--clr-accent-primary);
  outline-offset: 2px;
}

#theme-toggle:focus:not(:focus-visible) {
  outline: none;
  color: var(--clr-accent-primary);
}

.theme-icon {
  width: 18px; /* Explicit size, matches HTML */
  height: 18px; /* Explicit size, matches HTML */
}

/* Publications social icons */
.publications-social {
  display: flex;
  justify-content: flex-start;
  gap: 3.5rem;
  margin: 1rem 0;
}

.publications-social .social-icon {
  width: 96px;
  height: 96px;
  transition: transform 0.2s ease, color 0.2s ease;
}

.publications-social a.large-icon-link {
  display: flex;
    flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  color: var(--text-color);
  text-decoration: none;
}

.publications-social a.large-icon-link:hover .social-icon {
  transform: scale(1.1);
  color: var(--clr-accent-primary);
}

.publications-social a.large-icon-link span {
  font-size: 0.9rem;
}

/* Video Link in Research Section */
.video-link-container {
  margin: 3rem 0;
  max-width: 100%;
  display: flex;
  justify-content: center;
  padding: 0 var(--space-s);
}

.video-link {
  display: block;
  position: relative;
    width: 100%;
  max-width: 800px;
  background-color: var(--clr-background-secondary);
  border-radius: var(--border-radius);
  padding: 0;
  box-shadow: var(--shadow-standard);
  border: 1px solid var(--clr-border-primary);
  transition: transform 0.1s ease, box-shadow 0.1s ease, border-color 0.1s ease !important;
  text-decoration: none;
}

.video-link:hover, .video-link.touch-active {
  transform: scale(1.02);
  box-shadow: 0 10px 20px var(--clr-shadow-color);
  border-color: var(--clr-accent-primary);
  text-decoration: none;
}

.clickable-video {
    width: 100%;
  height: auto;
  display: block;
  cursor: pointer;
  border-radius: var(--border-radius);
  transition: transform 0.3s ease;
}

.video-caption {
  margin: 0 0 1rem 0;
  padding-top: var(--space-s);
  padding-left: var(--space-s);
  padding-right: var(--space-s);
  color: var(--clr-text-headings);
  text-align: center;
  font-size: 1.4rem;
  font-weight: var(--font-weight-medium);
  padding-bottom: 0.75rem;
  transition: color 0.3s ease;
  text-decoration: none;
  border-bottom: 2px solid var(--clr-border-primary);
  position: relative;
}

/* Add animated underline effect to video caption like project cards */
.video-caption::after {
  content: '';
  position: absolute;
  bottom: -2px; /* Position to cover the border line */
  left: 0;
  width: 100%;
  height: 2px;
  background-color: var(--clr-accent-primary);
  transform: scaleX(0);
  transform-origin: right;
  transition: transform 0.3s ease;
}

.video-link:hover .video-caption, 
.video-link.touch-active .video-caption {
  color: var(--clr-accent-primary);
}

.video-link:hover .video-caption::after,
.video-link.touch-active .video-caption::after {
  transform: scaleX(1);
  transform-origin: left;
}

/* For mobile devices */
@media (max-width: 768px) {
  .video-link {
    max-width: 100%;
  }
  
  .video-caption {
    font-size: 1.2rem;
    margin-bottom: 0.75rem;
  }
}

/* iOS/Mobile video background fix for transparent videos */
@media (max-width: 768px) {
  /* Fix transparent video backgrounds by setting container background */
  #education .video-link {
    background-color: var(--clr-background-secondary) !important;
  }
  
  #education .clickable-video {
    background-color: var(--clr-background-secondary);
    background-image: linear-gradient(var(--clr-background-secondary), var(--clr-background-secondary));
  }
}

/* Additional iOS-specific fix using -webkit-playsinline support detection */
@supports (-webkit-overflow-scrolling: touch) {
  /* iOS Safari specific video background fixes */
  #education .video-link {
    background-color: var(--clr-background-secondary) !important;
  }
  
  #education .clickable-video {
    background-color: var(--clr-background-secondary);
    background-image: linear-gradient(var(--clr-background-secondary), var(--clr-background-secondary));
  }
}

/* Video loading indicator */
.video-loading {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: rgba(0, 0, 0, 0.5);
  color: white;
  z-index: 5;
  border-radius: var(--border-radius);
}

.video-loading span {
  background-color: rgba(0, 0, 0, 0.7);
  padding: 0.75rem 1.5rem;
  border-radius: var(--border-radius);
  font-size: 1rem;
}

/* Interests Carousel */
.carousel-container {
  width: 100%;
  height: 300px;
  overflow: hidden;
  margin: var(--space-l) 0;
  position: relative;
}

.carousel-track {
  display: flex;
  height: 100%;
  gap: var(--space-s);
  animation: none; /* JavaScript will handle animation */
  will-change: transform; /* Optimize for animations */
}

.carousel-track img,
.carousel-track video {
  height: 300px;
  width: auto;
  object-fit: cover;
  border-radius: var(--border-radius);
  box-shadow: var(--shadow-standard);
  flex-shrink: 0;
}

.carousel-track video {
  background: var(--clr-background-secondary);
}



@media (max-width: 768px) {
  .carousel-container {
    height: 250px;
  }
  
  .carousel-track img,
  .carousel-track video {
    height: 250px;
  }
}

/* Reduced motion support for carousel */
@media (prefers-reduced-motion: reduce) {
  .carousel-track {
    animation: none !important;
  }
}