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

body {
  font-family: Arial, Helvetica, sans-serif;
  line-height: 1.6;
  background-color: #f9f9f9;
  color: #333;
}

/* Header */
.header {
  position: relative;
  height: 400px;
  background-image: url('images/header.png');
  background-size: cover;
  background-position: center;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
}

.header h1 {
  color: #fff;
  font-size: 3rem;
  font-weight: bold;
  text-shadow: 2px 2px 6px rgba(0, 0, 0, 0.6);
  background-color: rgba(0, 0, 0, 0.3);
  padding: 20px;
  border-radius: 10px;
}

/* Navigation bar */
nav {
  background-color: #333;
}

nav ul {
  display: flex;
  justify-content: center;
  list-style: none;
}

nav ul li a {
  color: #fff;
  padding: 14px 20px;
  display: block;
  text-decoration: none;
  transition: background 0.3s ease;
}

nav ul li a:hover,
nav ul li a.active {
  background-color: #555;
}

/* Page content container */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 20px;
}

/* Titles */
.section-title {
  font-size: 2rem;
  margin-bottom: 1rem;
  text-align: center;
  color: #222;
}

/* CV oage */
.cv-links {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1rem;
}

.cv-links a {
  background: linear-gradient(to right, #6ee7b7, #60a5fa);
  color: #222;
  padding: 1rem 2rem;
  border-radius: 8px;
  text-decoration: none;
  font-weight: bold;
  transition: opacity 0.2s ease;
}

.cv-links a:hover {
  opacity: 0.8;
}

/* Research page */
.research-section {
  margin-bottom: 2rem;
  background-color: #fff;
  border: 1px solid #ddd;
  border-radius: 8px;
  padding: 1rem 1.5rem;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.research-section h2 {
  margin-bottom: 0.5rem;
  color: #222;
}

.research-section p {
  margin-bottom: 1rem;
  text-align: justify;
}

/* Projects page */
.project-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.project-card {
  background-color: #fff;
  border: 1px solid #ddd;
  padding: 1rem;
  border-radius: 8px;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.project-card h3 {
  margin-bottom: 0.5rem;
  color: #222;
}

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

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

.skill-item {
  background-color: #fff;
  border: 1px solid #ddd;
  padding: 1rem;
  border-radius: 8px;
  text-align: center;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.skill-item h3 {
  margin-bottom: 0.5rem;
}

/* Tutorials page */
.tutorial-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1rem;
}

.tutorial-grid h3 {
  text-align: center;
}

.tutorial-section {
  background-color: #fff;
  border: 1px solid #ddd;
  border-radius: 8px;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.tutorial-section h3 {
  background-color: lightslategrey;
  color: #fff;
  margin: 0;
  padding: 0.5rem;
  border-top-left-radius: 8px;
  border-top-right-radius: 8px;
  font-size: 1.2rem;
}

.tutorial-section ul {
  list-style: none;
  padding: 0.5rem 1rem 1rem 1rem;
}

.tutorial-section ul li {
  margin-bottom: 0.5rem;
}

.tutorial-section ul li a {
  text-decoration: none;
  color: #007bff;
}

.tutorial-section ul li a:hover {
  text-decoration: underline;
}

.tutorial-intro {
  text-align: center;
  margin-bottom: 2rem;
}