* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: Arial, Helvetica, sans-serif;
}

body {
  background: #f4f7fb;
  color: #1f2937;
  line-height: 1.6;
}

header {
  background: linear-gradient(135deg, #2563eb, #1e40af);
  color: white;
  padding: 60px 20px;
  text-align: center;
}

header h1 {
  font-size: 3rem;
  margin-bottom: 10px;
}

header p {
  font-size: 1.2rem;
  opacity: 0.9;
}

.profile-photo-container {
  display: flex;
  justify-content: center;
  margin-bottom: 20px;
}

.profile-photo {
  width: 180px;
  height: 180px;
  border-radius: 50%;
  object-fit: cover;
  border: 5px solid rgba(255, 255, 255, 0.8);
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.25);
  background: white;
}

nav {
  background: white;
  display: flex;
  justify-content: center;
  gap: 30px;
  padding: 15px;
  position: sticky;
  top: 0;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
  z-index: 100;
}

nav a {
  text-decoration: none;
  color: #1e3a8a;
  font-weight: bold;
  transition: 0.3s;
}

nav a:hover {
  color: #2563eb;
}

.container {
  width: 90%;
  max-width: 1100px;
  margin: auto;
  padding: 50px 0;
}

section {
  margin-bottom: 60px;
}

.section-title {
  font-size: 2rem;
  margin-bottom: 20px;
  color: #1e3a8a;
  position: relative;
}

.section-title::after {
  content: "";
  width: 70px;
  height: 4px;
  background: #2563eb;
  position: absolute;
  left: 0;
  bottom: -10px;
  border-radius: 10px;
}

.about {
  background: white;
  padding: 30px;
  border-radius: 15px;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.08);
}

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 20px;
}

.card {
  background: white;
  padding: 25px;
  border-radius: 15px;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.08);
  transition: transform 0.3s ease;
}

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

.card h3 {
  margin-bottom: 15px;
  color: #1d4ed8;
}

.skills-list {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 15px;
}

.skill {
  background: #dbeafe;
  color: #1e3a8a;
  padding: 8px 15px;
  border-radius: 20px;
  font-size: 0.9rem;
  font-weight: bold;
}

.timeline {
  border-left: 4px solid #2563eb;
  padding-left: 20px;
}

.timeline-item {
  margin-bottom: 30px;
  position: relative;
}

.timeline-item::before {
  content: "";
  width: 15px;
  height: 15px;
  background: #2563eb;
  border-radius: 50%;
  position: absolute;
  left: -30px;
  top: 5px;
}

.timeline-item h3 {
  color: #1e3a8a;
}

.certification {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 15px;
  background: white;
  border-radius: 12px;
  margin-bottom: 15px;
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.06);
}

.btn {
  display: inline-block;
  margin-top: 20px;
  padding: 12px 20px;
  background: #2563eb;
  color: white;
  border-radius: 8px;
  text-decoration: none;
  transition: 0.3s;
}

.btn:hover {
  background: #1d4ed8;
}

footer {
  background: #111827;
  color: white;
  text-align: center;
  padding: 30px 20px;
}

.dark-mode {
  background: #111827;
  color: #f9fafb;
}

.dark-mode .card,
.dark-mode .about,
.dark-mode .certification,
.dark-mode nav {
  background: #1f2937;
  color: white;
}

.dark-mode .section-title,
.dark-mode nav a,
.dark-mode .card h3 {
  color: #93c5fd;
}

.toggle-container {
  position: fixed;
  bottom: 20px;
  right: 20px;
}

.toggle-btn {
  background: #2563eb;
  color: white;
  border: none;
  padding: 12px 16px;
  border-radius: 50%;
  cursor: pointer;
  font-size: 1rem;
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
}

@media (max-width: 768px) {
  header h1 {
    font-size: 2.2rem;
  }

  nav {
    gap: 15px;
    flex-wrap: wrap;
  }
}