/* RESET */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: "Open Sans", system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
  color: #222;
}

/* NAVBAR */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  background: #21252b;
  color: #fff;
  z-index: 1000;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.25);
}

.nav-inner {
  max-width: 1120px;
  margin: 0 auto;
  padding: 12px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand {
  font-family: "Montserrat", sans-serif;
  font-weight: 600;
  color: #f6b01a;
  text-decoration: none;
}

.nav-links a {
  margin-left: 18px;
  color: #f8fafc;
  text-decoration: none;
  font-size: 0.9rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.nav-links a:hover {
  color: #f6b01a;
}

.nav-icon-link {
  background: none;
  border: 1px solid rgba(248, 250, 252, 0.2);
  padding: 4px 10px;
  border-radius: 3px;
}

/* HERO */
.hero {
  position: relative;
  height: 100vh;
  min-height: 600px;
  background-image: url("img/hero-bg.jpg");
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
  display: flex;
  align-items: center;
  justify-content: center;
}

.hero-overlay {
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at top, rgba(0, 0, 0, 0.45), rgba(0, 0, 0, 0.85));
}

.hero-content {
  position: relative;
  text-align: center;
  color: #fff;
  max-width: 720px;
  padding: 0 20px;
  margin-top: 40px;
}

.hero-outdated {
  font-size: 0.95rem;
  margin-bottom: 18px;
}

.accent {
  color: #f6b01a;
  font-weight: 600;
}

.hero-avatar-wrapper {
  width: 230px;          
  height: 230px;         
  border-radius: 50%;
  overflow: hidden;
  border: 6px solid #fff;  
  margin: 0 auto 30px auto;
}


.hero-avatar {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.hero-name {
  font-family: "Montserrat", sans-serif;
  font-weight: 700;
  font-size: 3.6rem;       
  letter-spacing: 0.03em;  
  margin-bottom: 14px;
}

.hero-tagline {
  font-size: 1.3rem;       
  font-weight: 500;
  margin-bottom: 32px;
}


.hero-button {
  background: #ffffff;
  color: #222;
  border: none;
  padding: 12px 32px;
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: 3px;
  cursor: pointer;
  transition: background 0.15s ease, transform 0.15s ease;
}

.hero-button:hover {
  background: #f4f4f4;
  transform: translateY(-1px);
}

/* COMMON SECTION STYLES */
.section {
  padding: 80px 20px;
}

.section-light {
  background: #f4f5f7;
}

.section-blue {
  background: #1d7db8;
  color: #fff;
}

.section-dark {
  background: #20252a;
  color: #f9fafb;
}

.section-inner {
  max-width: 1120px;
  margin: 0 auto;
}

.section-inner h2 {
  font-family: "Montserrat", sans-serif;
  font-size: 2.1rem;
  text-align: center;
  margin-bottom: 12px;
}

.section-inner p {
  text-align: center;
  margin-bottom: 12px;
}

.muted {
  opacity: 0.8;
  font-size: 0.9rem;
}

/* ABOUT */
.about-body {
  margin-top: 20px;
  display: flex;
  gap: 40px;
  align-items: center;
  padding: 0 10px;
}

.about-photo img {
  width: 220px;
  height: 220px;
  border-radius: 50%;
  object-fit: cover;
  border: 6px solid #fff;
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.15);
}

.about-text h2 {
  font-family: "Montserrat", sans-serif;
  font-size: 1.8rem;
  margin-bottom: 4px;
}

.about-text h3 {
  font-size: 1rem;
  margin-bottom: 16px;
  color: #555;
}

.about-text p {
  text-align: left;
  margin-bottom: 10px;
}

.about-text ul {
  margin-left: 18px;
  margin-top: 8px;
}

.about-text li {
  margin-bottom: 4px;
}

.social-links {
  margin-top: 14px;
}

.social-links a {
  margin-right: 12px;
  text-decoration: none;
  color: #1d7db8;
  font-weight: 600;
}

.social-links a:hover {
  text-decoration: underline;
}

/* Learn more buttons */
.learn-more {
  text-align: center;
  margin-top: 40px;
}

.learn-more h3 {
  font-family: "Montserrat", sans-serif;
  margin-bottom: 18px;
}

.learn-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  justify-content: center;
}

.learn-buttons button,
.learn-buttons .btn-dark {
  padding: 10px 22px;
  border-radius: 3px;
  border: none;
  cursor: pointer;
  font-weight: 600;
  font-size: 0.95rem;
  background: #ffffff;
  color: #222;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.learn-buttons .btn-dark {
  background: #333;
  color: #fff;
}

.learn-buttons button:hover,
.learn-buttons .btn-dark:hover {
  opacity: 0.9;
}

/* SKILLS */
.skills-grid {
  margin-top: 40px;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 28px;
}

.skill-card {
  background: rgba(0, 0, 0, 0.12);
  border-radius: 8px;
  padding: 22px 20px;
  text-align: center;
}

.skill-icon {
  font-size: 2rem;
  margin-bottom: 10px;
}

.skill-card h3 {
  font-family: "Montserrat", sans-serif;
  font-size: 1.05rem;
  margin-bottom: 8px;
}

/* PROJECTS */
.projects-grid {
  margin-top: 32px;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}

.project-card {
  background: #ffffff;
  border-radius: 6px;
  overflow: hidden;
  box-shadow: 0 3px 12px rgba(0, 0, 0, 0.08);
}

.project-image-wrapper {
  position: relative;
  height: 180px;
  overflow: hidden;
}

.project-image-wrapper img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.project-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(to top, rgba(0, 0, 0, 0.75), transparent);
  color: #fff;
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  padding: 12px 14px;
  font-size: 0.9rem;
}

.project-overlay h3 {
  font-family: "Montserrat", sans-serif;
  font-size: 1.05rem;
}

.project-text {
  padding: 14px 16px 16px 16px;
  font-size: 0.95rem;
}

.projects-footer {
  text-align: center;
  margin-top: 28px;
}

.btn-dark {
  display: inline-block;
  background: #333;
  color: #fff;
  padding: 10px 22px;
  border-radius: 4px;
  text-decoration: none;
  font-weight: 600;
}

/* PAPERS */
.papers-list {
  margin-top: 32px;
}

.paper-item {
  margin-bottom: 18px;
}

.paper-meta {
  font-size: 0.9rem;
  opacity: 0.9;
}

/* CERTIFICATIONS */
.cert-list {
  list-style: none;
  max-width: 720px;
  margin: 24px auto 0 auto;
}

.cert-list li {
  margin-bottom: 10px;
  text-align: left;
}

.cert-list a {
  color: #1d7db8;
  text-decoration: none;
  font-weight: 600;
}

.cert-list a:hover {
  text-decoration: underline;
}

.cert-note {
  margin-top: 12px;
  font-size: 0.85rem;
  opacity: 0.8;
}

/* TIMELINE */
.timeline {
  margin-top: 40px;
  border-left: 2px solid #ddd;
  padding-left: 24px;
}

.timeline-item {
  position: relative;
  margin-bottom: 32px;
}

.timeline-dot {
  position: absolute;
  left: -11px;
  top: 4px;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: #f6b01a;
  border: 2px solid #fff;
  box-shadow: 0 0 0 2px #ddd;
}

.timeline-content {
  padding-left: 4px;
}

.timeline-date {
  font-weight: 600;
  margin-bottom: 4px;
  color: #555;
}

.timeline-content h3 {
  font-family: "Montserrat", sans-serif;
  font-size: 1rem;
  margin-bottom: 4px;
}

/* CONTACT */
.contact-grid {
  max-width: 720px;
  margin: 26px auto 0 auto;
}

.contact-form input,
.contact-form textarea {
  width: 100%;
  margin-bottom: 12px;
  padding: 10px 12px;
  border-radius: 4px;
  border: 1px solid #444;
  background: #111827;
  color: #f9fafb;
  font-family: inherit;
}

.contact-form textarea {
  min-height: 130px;
  resize: vertical;
}

.contact-form button {
  background: #1d7db8;
  color: #fff;
  border: none;
  padding: 10px 22px;
  border-radius: 4px;
  cursor: pointer;
  font-weight: 600;
}

/* FOOTER */
.footer {
  padding: 18px 20px;
  text-align: center;
  background: #f9fafb;
  font-size: 0.85rem;
}

.footer-links a {
  margin-left: 10px;
  text-decoration: none;
  color: #1d7db8;
}

/* Back to top */
.back-to-top {
  position: fixed;
  right: 18px;
  bottom: 18px;
  width: 34px;
  height: 34px;
  border-radius: 4px;
  border: none;
  background: rgba(148, 163, 184, 0.9);
  color: #111827;
  cursor: pointer;
  display: none;
}

/* RESPONSIVE */
@media (max-width: 860px) {
  .about-body {
    flex-direction: column;
    text-align: center;
  }
  .about-text p,
  .about-text ul {
    text-align: left;
  }
}

@media (max-width: 720px) {
  .nav-inner {
    flex-direction: column;
    align-items: flex-start;
  }
  .nav-links {
    margin-top: 8px;
    display: flex;
    flex-wrap: wrap;
  }
  .nav-links a {
    margin: 6px 12px 0 0;
  }
}