:root {
  --bg-color: #f8f9fa;
  --text-color: #111111;
  --text-color-secondary: #555555;
  --border-color: #e0e0e0;
  --card-bg-color: #ffffff;
  --header-bg: rgba(248, 249, 250, 0.85);
  --accent-color: #1a202c;
  --accent-color-hover: #000000;
  --accent-text-color: #ffffff;
  --spotify-card-bg: #ffffff;
  --spotify-input-border: #d5d5d5;
  --spotify-button-bg: #171717;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: 'Roboto', sans-serif;
  background-color: var(--bg-color);
  color: var(--text-color-secondary);
  line-height: 1.7;
  transition: background-color 0.3s ease, color 0.3s ease;
}

header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px 40px;
  background-color: var(--header-bg);
  backdrop-filter: blur(10px);
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.02);
  border-bottom: 1px solid var(--border-color);
  transition: background-color 0.3s ease, border-color 0.3s ease;
}

header h1 {
  margin: 0;
  font-size: 24px;
  font-family: 'Poppins', sans-serif;
  color: var(--text-color);
}

header h1 a {
  text-decoration: none;
  color: inherit;
  transition: color 0.3s ease;
}

header h1 a:hover {
  color: var(--accent-color);
}

nav {
  display: flex;
  align-items: center;
}

nav a {
  margin-left: 20px;
  text-decoration: none;
  color: var(--text-color-secondary);
  font-weight: 500;
  font-family: 'Poppins', sans-serif;
  transition: color 0.3s ease;
}

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

.nav-indicator {
  position: absolute;
  bottom: 0;
  left: 0;
  height: 2px;
  background-color: var(--accent-color);
  width: 0;
  transition: all 0.3s cubic-bezier(0.23, 1, 0.32, 1);
}

.scrollable-section {
  padding: 80px 24px;
  max-width: 672px;
  margin: auto;
  overflow-x: hidden; 
}

h2, h3 {
  font-family: 'Poppins', sans-serif;
  font-weight: 700;
  color: var(--text-color);
}

h2.section-title {
  text-align: center;
  font-size: 2.5rem;
  font-weight: 900;
  letter-spacing: -0.02em;
  margin-bottom: 40px;
}

.divider {
  border-bottom: 1px solid var(--border-color);
  margin: 32px 0;
  max-width: 672px;
  margin-left: auto;
  margin-right: auto;
}

.profile {
  display: flex;
  align-items: center;
  margin-bottom: 32px;
}

.profile img {
  width: 180px;
  height: 180px;
  border-radius: 50%;
  margin-right: 40px;
  box-shadow: 0 8px 25px rgba(0,0,0,0.08);
  border: 4px solid var(--card-bg-color);
}

.profile h2 {
  font-family: 'Poppins', sans-serif;
  font-size: 3.5rem;
  font-weight: 900;
  line-height: 1.1;
  letter-spacing: -0.03em;
  margin-bottom: 10px;
}

#home h3.subtitle {
  font-family: 'Poppins', sans-serif;
  font-size: 1.5rem;
  font-weight: 400;
  color: var(--text-color-secondary);
  margin: 0 0 15px 0;
}

.cta-link {
  color: var(--text-color);
  font-weight: 700;
}
.cta-link:hover {
  text-decoration: underline;
}

.iframe-container {
  position: relative;
  padding-bottom: 56.25%;
  height: 0;
  overflow: hidden;
  border-radius: 12px;
  border: 1px solid var(--border-color);
}
.iframe-container iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  border: 0;
}

.spotify-container {
  max-width: 600px;
  margin: auto;
  background: var(--spotify-card-bg);
  padding: 40px;
  border-radius: 12px;
  border: 1px solid var(--border-color);
  box-shadow: 0 8px 20px hsla(0, 0%, 0%, 0.05);
}

.spotify-input {
  padding: 15px 5px;
  width: 100%;
  border-radius: 0;
  border: none;
  border-bottom: 2px solid var(--border-color);
  background-color: transparent;
  color: var(--text-color);
  font-size: 16px;
  outline: none;
  transition: border-color 0.3s ease;
  box-sizing: border-box;
  font-family: 'Roboto', sans-serif;
}
.spotify-input:focus {
  border-color: var(--accent-color);
  box-shadow: none;
}
.spotify-input::placeholder {
  color: var(--text-color-secondary);
  opacity: 0.8;
}

.spotify-button {
  position: relative;
  z-index: 1;
  display: inline-block;
  padding: 12px 28px;
  background-color: transparent;
  color: var(--accent-color);
  border: 1px solid var(--accent-color);
  border-radius: 8px;
  text-decoration: none;
  font-family: 'Poppins', sans-serif;
  font-weight: 500;
  transition: all 0.4s cubic-bezier(0.23, 1, 0.32, 1);
  overflow: hidden;
  font-size: 1rem;
  width: 100%;
  box-sizing: border-box;
  text-align: center;
  margin-top: 25px;
  margin-bottom: 30px;
  cursor: pointer;
}
.spotify-button::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 101%;
  height: 101%;
  z-index: -1;
  background-color: var(--accent-color);
  transform: translateX(-101%);
  transition: transform 0.4s cubic-bezier(0.23, 1, 0.32, 1);
}
.spotify-button:hover {
  color: var(--accent-text-color);
  transform: translateY(-4px);
  box-shadow: 0 8px 15px hsla(0, 0%, 0%, 0.1);
}
.spotify-button:hover::before {
  transform: translateX(0);
}
.spotify-button i {
    margin-right: 10px;
}

#skills {
  text-align: center;
}
.skill-icons {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 30px;
  margin-top: 20px;
}
.skill-icon {
  width: 50px;
  height: 50px;
  transform: scale(1);
  transition: all 0.3s ease-in-out;
}
.skill-icon:hover {
  transform: scale(1.2);
}

.project-gallery {
  display: flex;
  flex-wrap: wrap;
  gap: 24px;
  justify-content: center;
}

.project-card {
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 24px 28px;
  background: var(--card-bg-color);
  width: calc(50% - 12px - 56px); 
  min-width: 280px; 
  box-shadow: 0 4px 6px rgba(0,0,0,0.03);
  transition: all 0.3s ease;
  box-sizing: border-box;
}

.project-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 8px 15px rgba(0,0,0,0.05);
  border-color: var(--text-color);
}

.project-card h3 {
  font-family: 'Poppins', sans-serif;
  margin-top: 0;
  font-weight: 700;
  font-size: 1.25rem;
}

.project-tags {
  margin: 15px 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.project-tags span {
  background: var(--bg-color);
  border: 1px solid var(--border-color);
  color: var(--text-color-secondary);
  padding: 4px 10px;
  border-radius: 12px;
  font-size: 13px;
  font-weight: 500;
  font-family: 'Roboto', sans-serif;
}

.project-links {
  margin-top: 24px;
}

.resume-item {
    margin-bottom: 25px;
    padding-bottom: 25px;
    border-bottom: 1px solid var(--border-color);
}
.resume-item:last-child {
    border-bottom: none;
}
.resume-item h3 {
    font-family: 'Poppins', sans-serif;
    font-size: 20px;
    margin-top: 0;
    margin-bottom: 5px;
    font-weight: 700;
    display: flex;
    align-items: center;
}
.resume-item h3 i {
    margin-right: 12px;
    color: var(--text-color-secondary);
    font-size: 1.1rem;
}

.resume-item p {
    margin-top: 0;
    margin-bottom: 5px;
}
.resume-item ul {
    list-style-type: disc;
    margin-left: 20px;
    padding-left: 0;
}
.resume-item ul li {
    margin-bottom: 5px;
}
.date-location {
    font-size: 0.9em;
    color: var(--text-color-secondary);
    margin-bottom: 10px;
}
.skills-used {
    font-size: 0.9em;
    color: var(--text-color-secondary);
    margin-top: 10px;
}

.certificate-display {
  display: flex;
  align-items: center;
  gap: 20px;
  flex-wrap: wrap;
}
.certificate-info {
  flex: 1;
  min-width: 200px;
}
.certificate-thumbnail {
  width: 150px;
  height: auto;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

#contact {
  text-align: center;
}

.socials {
  display: flex;
  justify-content: center;
  gap: 16px;
  margin-top: 16px;
}
.social-icon img {
  width: 32px;
  height: 32px;
  transition: all 0.3s ease;
}
.social-icon:hover img {
  transform: scale(1.1) translateY(-3px);
}

.btn-modern {
  position: relative;
  z-index: 1;
  margin-top: 16px;
  display: inline-block;
  padding: 10px 20px;
  background-color: transparent;
  color: var(--accent-color);
  border: 1px solid var(--accent-color);
  border-radius: 6px;
  text-decoration: none;
  font-family: 'Poppins', sans-serif;
  font-weight: 500;
  transition: all 0.4s cubic-bezier(0.23, 1, 0.32, 1);
  overflow: hidden;
}

.btn-modern::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 101%;
  height: 101%;
  z-index: -1;
  background-color: var(--accent-color);
  transform: translateX(-101%);
  transition: transform 0.4s cubic-bezier(0.23, 1, 0.32, 1);
}

.btn-modern:hover {
  color: var(--accent-text-color);
  transform: translateY(-2px);
  box-shadow: 0 4px 8px rgba(0,0,0,0.05);
}

.btn-modern:hover::before {
  transform: translateX(0);
}

.btn-modern i {
    margin-right: 8px;
}

.footer {
  text-align: center;
  margin-top: 32px;
  padding: 32px 16px;
  color: var(--text-color-secondary);
  font-size: 14px;
  font-family: 'Roboto', sans-serif;
  border-top: 1px solid var(--border-color);
  margin-top: 64px;
}

#back-to-top {
  position: fixed;
  bottom: 20px;
  right: 20px;
  width: 40px;
  height: 40px;
  background-color: var(--accent-color);
  color: var(--accent-text-color);
  border: none;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  text-decoration: none;
  font-size: 1rem;
  box-shadow: 0 4px 8px rgba(0,0,0,0.15);
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: all 0.3s ease;
}

#back-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

#back-to-top:hover {
  background-color: var(--accent-color-hover);
}


@media (max-width: 768px) {
  header {
    flex-direction: column;
    padding: 15px 20px;
  }
  header h1 { margin-bottom: 10px; }
  nav { margin-top: 10px; flex-wrap: wrap; justify-content: center; }
  nav a { margin: 5px 8px; }
  
  .profile { flex-direction: column; text-align: center; }
  .profile img { margin-right: 0; margin-bottom: 15px; width: 140px; height: 140px; }
  .profile h2 { font-size: 2.5rem; }
  #home h3.subtitle { font-size: 1.25rem; }
  
  h2.section-title { font-size: 2rem; }
  
  .skill-icons { gap: 20px; }
  .socials { flex-wrap: wrap; justify-content: center; gap: 10px; }
  .project-card { width: 100%; }
  .resume-item h3, .project-card h3 { font-size: 18px; }
  .resume-item p, .date-location, .skills-used { font-size: 0.9em; }
  .certificate-display { flex-direction: column; align-items: flex-start; }
  .certificate-thumbnail { width: 100%; max-width: 200px; }
  
  .spotify-container { padding: 30px; }
  .spotify-input { font-size: 15px; }
  .spotify-button { padding: 10px 20px; font-size: 0.9rem; }
}

@media (max-width: 480px) {
  header h1 { font-size: 20px; }
  nav a { font-size: 13px; margin: 5px 6px; }
  .scrollable-section h2 { font-size: 22px; }
  
  .profile h2 { font-size: 2.2rem; }
  #home h3.subtitle { font-size: 1.1rem; }
  .profile p { font-size: 15px; }
  
  .btn-modern { padding: 8px 15px; font-size: 14px; }
  
  #back-to-top { width: 35px; height: 35px; font-size: 0.9rem; }
  
  .spotify-container { padding: 25px; }
  .spotify-input { font-size: 14px; }
  .spotify-button { padding: 10px 15px; font-size: 0.9rem; }
}