:root {
  --primary-color: #66b0ff;
  --secondary-color: #aab2bd;
  --background-color: #121212;
  --text-color: #e0e0e0;
  --header-bg: #1e1e1e;
  --footer-bg: #000;
  --footer-text: #ddd;
  --card-bg: #1e1e1e;
  --shadow: 0 4px 6px rgba(255, 255, 255, 0.1);
  --transition: all 0.3s ease;
}

[data-theme="light"] {
  --primary-color: #007bff;
  --secondary-color: #6c757d;
  --background-color: #f8f9fa;
  --text-color: #333;
  --header-bg: #fff;
  --footer-bg: #343a40;
  --footer-text: #fff;
  --card-bg: #fff;
  --shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

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

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  line-height: 1.6;
  color: var(--text-color);
  background-color: var(--background-color);
  transition: var(--transition);
}

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

a:hover {
  color: #0056b3;
  text-decoration: underline;
}

ul {
  list-style: none;
}

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

/* Header */
header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background-color: var(--header-bg);
  box-shadow: var(--shadow);
  padding: 1rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 1.5rem;
  font-weight: bold;
  color: var(--text-color);
}

nav ul {
  display: flex;
  gap: 1.5rem;
}

nav a {
  color: var(--text-color);
  font-weight: 500;
}

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

.mobile-menu-btn {
  display: none;
  font-size: 1.5rem;
  background: none;
  border: none;
  cursor: pointer;
  color: var(--text-color);
}

.theme-toggle {
  background: none;
  border: none;
  color: var(--text-color);
  font-size: 1.2rem;
  cursor: pointer;
  padding: 0.5rem;
  transition: var(--transition);
  margin-left: 1rem;
}

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

/* Hero Section */
.hero {
  padding: 4rem 2rem;
  text-align: center;
  background: linear-gradient(135deg, var(--primary-color), #0056b3);
  color: #fff;
}

.profile-photo {
  width: 150px;
  height: 150px;
  border-radius: 50%;
  border: 4px solid #fff;
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
  margin-bottom: 1.5rem;
  object-fit: cover;
}

.hero h1 {
  font-size: 3rem;
  margin-bottom: 1rem;
}

.hero p {
  font-size: 1.25rem;
  margin-bottom: 2rem;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.cta-button {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  background-color: #fff;
  color: var(--primary-color);
  border-radius: 5px;
  font-weight: bold;
  transition: var(--transition);
}

.cta-button:hover {
  background-color: #f1f1f1;
  text-decoration: none;
  transform: translateY(-2px);
}

/* Sections */
section {
  padding: 4rem 2rem;
  max-width: 1200px;
  margin: 0 auto;
}

h2 {
  font-size: 2rem;
  margin-bottom: 2rem;
  text-align: center;
  color: var(--text-color);
  position: relative;
}

h2::after {
  content: '';
  display: block;
  width: 50px;
  height: 4px;
  background-color: var(--primary-color);
  margin: 0.5rem auto 0;
  border-radius: 2px;
}

/* About */
.about-content {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  text-align: center;
}

/* Skills */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 2rem;
}

.skill-category {
  background-color: var(--card-bg);
  padding: 1.5rem;
  border-radius: 8px;
  box-shadow: var(--shadow);
}

.skill-category h3 {
  margin-bottom: 1rem;
  color: var(--primary-color);
}

.skill-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.skill-tag {
  background-color: rgba(0, 123, 255, 0.1);
  color: var(--primary-color);
  padding: 0.25rem 0.5rem;
  border-radius: 4px;
  font-size: 0.9rem;
}

/* Experience */
.timeline {
  position: relative;
  max-width: 800px;
  margin: 0 auto;
}

.timeline-item {
  position: relative;
  padding-left: 2rem;
  margin-bottom: 2rem;
  border-left: 2px solid var(--primary-color);
}

.timeline-item::before {
  content: '';
  position: absolute;
  left: -9px;
  top: 0;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background-color: var(--primary-color);
  border: 4px solid var(--background-color);
}

.timeline-content {
  background-color: var(--card-bg);
  padding: 1.5rem;
  border-radius: 8px;
  box-shadow: var(--shadow);
}

.timeline-content h3 {
  margin-bottom: 0.5rem;
}

.timeline-content .date {
  font-size: 0.9rem;
  color: var(--secondary-color);
  margin-bottom: 1rem;
  display: block;
}

/* Projects */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
}

.project-card {
  background-color: var(--card-bg);
  padding: 1.5rem;
  border-radius: 8px;
  box-shadow: var(--shadow);
  transition: var(--transition);
}

.project-card:hover {
  transform: translateY(-5px);
}

.project-card h3 {
  margin-bottom: 0.5rem;
}

.project-links {
  margin-top: 1rem;
  display: flex;
  gap: 1rem;
}

/* Testimonials */
.testimonials-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
}

.testimonial-card {
  background-color: var(--card-bg);
  padding: 2rem;
  border-radius: 8px;
  box-shadow: var(--shadow);
  position: relative;
  font-style: italic;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
}

.testimonial-avatar {
  font-size: 3rem;
  color: var(--secondary-color);
  margin-bottom: 1rem;
}

.testimonial-card::before {
  content: '\201C';
  font-size: 4rem;
  color: var(--primary-color);
  opacity: 0.2;
  position: absolute;
  top: -10px;
  left: 1rem;
}

.testimonial-author {
  margin-top: 1.5rem;
  font-style: normal;
  border-top: 1px solid var(--secondary-color);
  padding-top: 1rem;
  width: 100%;
}

.testimonial-author h4 {
  margin-bottom: 0.2rem;
  color: var(--primary-color);
}

.testimonial-author span {
  font-size: 0.9rem;
  color: var(--secondary-color);
}

/* Contact */
.contact-container {
  text-align: center;
  max-width: 600px;
  margin: 0 auto;
}

.contact-links {
  display: flex;
  justify-content: center;
  gap: 2rem;
  margin-top: 2rem;
  flex-wrap: wrap;
}

.contact-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 1.1rem;
}

/* Footer */
footer {
  background-color: var(--footer-bg);
  color: var(--footer-text);
  text-align: center;
  padding: 2rem;
  margin-top: 4rem;
}

footer h2 {
  color: var(--footer-text);
}

footer a {
  color: #66b0ff;
}

footer a:hover {
  color: #fff;
  text-decoration: underline;
}

/* Responsive */
@media (max-width: 768px) {
  header {
    padding: 1rem;
  }

  nav {
    position: absolute;
    top: 100%;
    left: 0;
    width: 100%;
    background-color: var(--header-bg);
    padding: 1rem;
    box-shadow: var(--shadow);
    display: none;
  }

  nav.active {
    display: block;
  }

  nav ul {
    flex-direction: column;
    align-items: center;
  }

  .mobile-menu-btn {
    display: block;
  }

  .hero h1 {
    font-size: 2.5rem;
  }
}