/* ============================================
   Main Styles & Layout
   ============================================ */

/* Header / Navigation */
.header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: var(--header-height);
  background-color: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  box-shadow: var(--shadow-sm);
  z-index: var(--z-fixed);
  transition: all var(--transition-base);
}

.header.scrolled {
  box-shadow: var(--shadow-md);
}

.nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 100%;
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

.nav-logo {
  font-size: var(--fs-2xl);
  font-weight: var(--fw-bold);
  color: var(--color-primary);
}

.nav-menu {
  display: flex;
  gap: var(--space-md);
  align-items: center;
}

.nav-link {
  font-weight: var(--fw-medium);
  color: var(--color-text);
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-md);
  transition: all var(--transition-base);
  white-space: nowrap;
}

.nav-link:hover,
.nav-link.active {
  color: var(--color-primary);
  background-color: rgba(37, 99, 235, 0.1);
}

.nav-toggle {
  display: none;
  font-size: var(--fs-2xl);
  color: var(--color-text-dark);
}

/* Language Toggle */
.lang-toggle {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  margin-left: var(--space-md);
  flex-shrink: 0;
}

.lang-divider {
  color: var(--color-border);
  font-size: var(--fs-sm);
  user-select: none;
}

.lang-btn {
  background: none;
  border: 1.5px solid transparent;
  border-radius: var(--radius-sm);
  padding: 3px 8px;
  font-size: var(--fs-xs);
  font-weight: var(--fw-bold);
  letter-spacing: 0.05em;
  cursor: pointer;
  color: var(--color-text-light);
  transition: all var(--transition-fast);
}

.lang-btn:hover {
  color: var(--color-primary);
}

.lang-btn.active {
  color: var(--color-primary);
  border-color: var(--color-primary);
  background-color: rgba(37, 99, 235, 0.08);
}

/* Hero Section */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  position: relative;
  overflow: hidden;
  padding-top: var(--header-height);
}

.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1440 320"><path fill="%23ffffff" fill-opacity="0.1" d="M0,96L48,112C96,128,192,160,288,160C384,160,480,128,576,122.7C672,117,768,139,864,154.7C960,171,1056,181,1152,165.3C1248,149,1344,107,1392,85.3L1440,64L1440,320L1392,320C1344,320,1248,320,1152,320C1056,320,960,320,864,320C768,320,672,320,576,320C480,320,384,320,288,320C192,320,96,320,48,320L0,320Z"></path></svg>');
  background-size: cover;
  background-position: bottom;
}

.hero-content {
  text-align: center;
  color: white;
  z-index: 1;
  max-width: 800px;
  padding: 0 var(--space-lg);
}

.hero-image-wrapper {
  margin: 0 auto var(--space-xl);
}

.hero-image {
  width: 180px;
  height: 180px;
  border-radius: 50%;
  object-fit: cover;
  border: 6px solid white;
  box-shadow: var(--shadow-2xl);
  margin: 0 auto;
}

.hero-image-fallback {
  width: 180px;
  height: 180px;
  border-radius: 50%;
  border: 6px solid white;
  box-shadow: var(--shadow-2xl);
  background: rgba(255, 255, 255, 0.15);
  backdrop-filter: blur(10px);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--fs-4xl);
  font-weight: var(--fw-bold);
  color: white;
  letter-spacing: 2px;
  margin: 0 auto;
}

.hero-title {
  font-size: var(--fs-6xl);
  font-weight: var(--fw-extrabold);
  margin-bottom: var(--space-md);
  line-height: 1.1;
}

.hero-subtitle {
  font-size: var(--fs-2xl);
  margin-bottom: var(--space-sm);
  font-weight: var(--fw-medium);
  opacity: 0.95;
}

.hero-tagline {
  font-size: var(--fs-base);
  margin-bottom: var(--space-2xl);
  opacity: 0.85;
  font-weight: var(--fw-normal);
  font-style: italic;
  color: rgba(255, 255, 255, 0.9);
}

.hero-description {
  font-size: var(--fs-lg);
  margin-bottom: var(--space-2xl);
  opacity: 0.9;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.hero-buttons {
  display: flex;
  gap: var(--space-lg);
  justify-content: center;
  flex-wrap: wrap;
}

.hero-social {
  margin-top: var(--space-2xl);
  display: flex;
  justify-content: center;
}

/* About Section */
.about {
  background-color: var(--color-bg);
}

.about-content {
  max-width: var(--content-max-width);
  margin: 0 auto;
  font-size: var(--fs-lg);
  line-height: 1.8;
  color: var(--color-text);
}

.about-content p {
  margin-bottom: var(--space-lg);
}

/* Experience Section */
.experience {
  background-color: var(--color-bg-alt);
}

.experience-list {
  max-width: 900px;
  margin: 0 auto;
}

/* Achievements Section */
.achievements {
  background-color: var(--color-bg);
}

.achievement-card {
  text-align: center;
}

.achievement-card .icon-box {
  margin-left: auto;
  margin-right: auto;
}

/* Challenges Section */
.challenges {
  background-color: var(--color-bg-alt);
}

.challenge-card {
  padding: var(--space-2xl);
}

.challenge-problem {
  margin-bottom: var(--space-lg);
}

.challenge-problem-title {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: var(--fs-lg);
  font-weight: var(--fw-bold);
  color: var(--color-error);
  margin-bottom: var(--space-sm);
}

.challenge-action {
  margin-bottom: var(--space-lg);
}

.challenge-action-title {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: var(--fs-lg);
  font-weight: var(--fw-bold);
  color: var(--color-warning);
  margin-bottom: var(--space-sm);
}

.challenge-result {
  margin-bottom: var(--space-lg);
}

.challenge-result-title {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: var(--fs-lg);
  font-weight: var(--fw-bold);
  color: var(--color-success);
  margin-bottom: var(--space-sm);
}

.challenge-tags {
  margin-top: var(--space-lg);
  padding-top: var(--space-lg);
  border-top: 1px solid var(--color-border);
}

/* Projects Section */
.projects {
  background-color: var(--color-bg);
}

.project-card {
  overflow: hidden;
}

.project-image {
  width: 100%;
  height: 200px;
  object-fit: cover;
  border-radius: var(--radius-lg);
  margin-bottom: var(--space-lg);
}

.project-header {
  margin-bottom: var(--space-md);
}

.project-links {
  display: flex;
  gap: var(--space-md);
  margin-top: var(--space-lg);
}

/* Skills Section */
.skills {
  background-color: var(--color-bg-alt);
}

.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--space-2xl);
  max-width: 900px;
  margin: 0 auto;
}

.skill-category {
  background: var(--color-bg);
  padding: var(--space-xl);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-md);
}

.skill-category-title {
  font-size: var(--fs-xl);
  font-weight: var(--fw-bold);
  margin-bottom: var(--space-lg);
  color: var(--color-primary);
  text-align: center;
}

.skill-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  justify-content: center;
}

.skill-tag {
  background: linear-gradient(135deg, rgba(37, 99, 235, 0.1), rgba(124, 58, 237, 0.1));
  color: var(--color-text-dark);
  padding: var(--space-sm) var(--space-lg);
  border-radius: var(--radius-full);
  font-size: var(--fs-base);
  font-weight: var(--fw-medium);
  border: 2px solid transparent;
  transition: all var(--transition-base);
}

.skill-tag:hover {
  border-color: var(--color-primary);
  background: linear-gradient(135deg, rgba(37, 99, 235, 0.2), rgba(124, 58, 237, 0.2));
  transform: translateY(-2px);
}

/* Education Section */
.education {
  background-color: var(--color-bg);
}

.education-list {
  max-width: 900px;
  margin: 0 auto;
}

/* Certifications Section */
.certifications {
  background-color: var(--color-bg-alt);
}

.certification-card {
  text-align: center;
  padding: var(--space-xl);
}

.certification-logo {
  width: 80px;
  height: 80px;
  margin: 0 auto var(--space-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  border-radius: var(--radius-xl);
  color: white;
  font-size: var(--fs-3xl);
  font-weight: var(--fw-bold);
}

/* Languages Section */
.languages {
  background-color: var(--color-bg);
}

.language-card {
  text-align: center;
}

.language-level {
  display: inline-block;
  margin-top: var(--space-md);
  padding: var(--space-sm) var(--space-lg);
  background-color: var(--color-bg-alt);
  border-radius: var(--radius-full);
  font-weight: var(--fw-semibold);
  color: var(--color-primary);
}

/* Contact Section */
.contact {
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  color: white;
}

.contact .section-title,
.contact .section-subtitle {
  color: white;
}

.contact-content {
  max-width: 600px;
  margin: 0 auto;
  text-align: center;
}

.contact-cta {
  margin-bottom: var(--space-2xl);
}

.contact-message {
  font-size: var(--fs-lg);
  opacity: 0.9;
  margin-bottom: var(--space-xl);
  line-height: 1.6;
}

.contact-linkedin-btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-md);
  background-color: white;
  color: var(--color-primary);
  padding: var(--space-md) var(--space-2xl);
  border-radius: var(--radius-lg);
  font-size: var(--fs-lg);
  font-weight: 600;
  text-decoration: none;
  transition: all 0.3s ease;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.15);
}

.contact-linkedin-btn i {
  font-size: var(--fs-2xl);
}

.contact-linkedin-btn:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.25);
  background-color: #f0f0f0;
}

.contact-details {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
  margin-bottom: var(--space-xl);
}

.contact-item {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-md);
  font-size: var(--fs-md);
  opacity: 0.9;
}

.contact-item i {
  font-size: var(--fs-lg);
}

.contact-social {
  display: flex;
  justify-content: center;
  margin-top: var(--space-xl);
}

.contact-social .social-link {
  background-color: rgba(255, 255, 255, 0.2);
  color: white;
}

.contact-social .social-link:hover {
  background-color: white;
  color: var(--color-primary);
}

/* Footer */
.footer {
  background-color: var(--color-secondary);
  color: white;
  padding: var(--space-2xl) 0;
  text-align: center;
}

.footer-content {
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

.footer p {
  margin-bottom: var(--space-md);
  opacity: 0.8;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: var(--space-xl);
  margin-top: var(--space-lg);
}

.footer-link {
  color: white;
  opacity: 0.8;
  transition: opacity var(--transition-base);
}

.footer-link:hover {
  opacity: 1;
}

/* Back to Top Button */
.back-to-top {
  position: fixed;
  bottom: var(--space-xl);
  right: var(--space-xl);
  width: 50px;
  height: 50px;
  background-color: var(--color-primary);
  color: white;
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--fs-xl);
  box-shadow: var(--shadow-lg);
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-base);
  z-index: var(--z-fixed);
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
}

.back-to-top:hover {
  background-color: var(--color-primary-dark);
  transform: translateY(-4px);
}

/* Responsive Design */
@media (max-width: 768px) {
  /* Navigation */
  .nav-menu {
    position: fixed;
    top: var(--header-height);
    right: -100%;
    width: 80%;
    height: calc(100vh - var(--header-height));
    background-color: white;
    flex-direction: column;
    padding: var(--space-2xl);
    box-shadow: var(--shadow-xl);
    transition: right var(--transition-base);
    align-items: flex-start;
  }

  .nav-menu.active {
    right: 0;
  }

  .nav-toggle {
    display: block;
  }

  /* Hero */
  .hero-title {
    font-size: var(--fs-4xl);
  }

  .hero-subtitle {
    font-size: var(--fs-xl);
  }

  .hero-description {
    font-size: var(--fs-base);
  }

  .hero-buttons {
    flex-direction: column;
    align-items: center;
  }

  .hero-buttons .btn {
    width: 100%;
    max-width: 300px;
    justify-content: center;
  }

  /* Sections */
  .section {
    padding: var(--space-3xl) 0;
  }

  .section-title {
    font-size: var(--fs-3xl);
  }

  /* Timeline */
  .timeline {
    padding-left: var(--space-xl);
  }

  .timeline-item::before {
    left: calc(-1 * var(--space-xl) - 6px);
  }

  /* Grid */
  .grid-2,
  .grid-3 {
    grid-template-columns: 1fr;
  }

  .skills-grid {
    grid-template-columns: 1fr;
  }

  /* Back to Top */
  .back-to-top {
    bottom: var(--space-lg);
    right: var(--space-lg);
    width: 45px;
    height: 45px;
  }
}

@media (max-width: 480px) {
  .hero-title {
    font-size: var(--fs-3xl);
  }

  .hero-image,
  .hero-image-fallback {
    width: 150px;
    height: 150px;
  }

  .section-title {
    font-size: var(--fs-2xl);
  }

  .container {
    padding: 0 var(--space-md);
  }
}

/* Print Styles */
@media print {
  .header,
  .back-to-top,
  .hero-buttons,
  .hero-social {
    display: none;
  }

  .hero {
    min-height: auto;
    padding: var(--space-2xl) 0;
  }

  .section {
    page-break-inside: avoid;
  }
}

/* ============================================
   Certifications Toggle (Show More/Less)
   ============================================ */

.certifications-grid .card.hidden {
  display: none;
}

.toggle-icon {
  margin-left: var(--space-sm);
  transition: transform var(--transition-base);
}

.toggle-icon.rotated {
  transform: rotate(180deg);
}

/* ============================================
   Carousel for Challenges Section
   ============================================ */

.carousel-container {
  position: relative;
  display: flex;
  align-items: center;
  gap: var(--space-lg);
  margin: var(--space-2xl) 0;
}

.carousel-wrapper {
  flex: 1;
  overflow: hidden;
  border-radius: var(--radius-lg);
  position: relative;
}

.carousel-track {
  position: relative;
  width: 100%;
}

.carousel-item {
  display: none;
  width: 100%;
}

.carousel-item.active {
  display: block;
  animation: fadeIn 0.5s ease-in-out;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.carousel-btn {
  width: 50px;
  height: 50px;
  border-radius: 50%;
  border: 2px solid var(--color-primary);
  background-color: white;
  color: var(--color-primary);
  font-size: var(--fs-xl);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-base);
  flex-shrink: 0;
  z-index: 10;
}

.carousel-btn:hover {
  background-color: var(--color-primary);
  color: white;
  transform: scale(1.1);
}

.carousel-btn:active {
  transform: scale(0.95);
}

.carousel-indicators {
  display: flex;
  justify-content: center;
  gap: var(--space-sm);
  margin-top: var(--space-lg);
}

.carousel-indicator {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  border: 2px solid var(--color-primary);
  background-color: transparent;
  cursor: pointer;
  transition: all var(--transition-base);
  padding: 0;
}

.carousel-indicator:hover {
  background-color: rgba(37, 99, 235, 0.3);
}

.carousel-indicator.active {
  background-color: var(--color-primary);
  width: 32px;
  border-radius: 6px;
}

/* Responsive carousel */
@media (max-width: 768px) {
  .carousel-container {
    gap: var(--space-md);
  }

  .carousel-btn {
    width: 40px;
    height: 40px;
    font-size: var(--fs-lg);
  }
}