:root {
  --bg: #0b1120;
  --bg-elevated: #151e32;
  --text: #f8fafc;
  --text-muted: #94a3b8;
  --accent: #38bdf8;
  --accent-2: #818cf8;
  --border: #273552;
  --radius: 14px;
  --shadow: 0 10px 30px rgba(0,0,0,0.25);
  --max-width: 1100px;
  --nav-bg: rgba(11, 17, 32, 0.82);
}

html[data-theme="light"] {
  --bg: #f8fafc;
  --bg-elevated: #ffffff;
  --text: #0f172a;
  --text-muted: #475569;
  --border: #e2e8f0;
  --shadow: 0 10px 30px rgba(0,0,0,0.08);
  --nav-bg: rgba(248, 250, 252, 0.86);
}

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

html {
  scroll-behavior: smooth;
}

::selection {
  background: rgba(56, 189, 248, 0.35);
  color: var(--text);
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  overflow-x: hidden;
}

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

a:hover {
  text-decoration: none;
}

.skip-link {
  position: absolute;
  left: -999px;
  z-index: 100;
}

.skip-link:focus {
  left: 1rem;
  top: 1rem;
  background: var(--accent);
  color: var(--bg);
  padding: .5rem 1rem;
  border-radius: var(--radius);
}

.container {
  width: min(92%, var(--max-width));
  margin: 0 auto;
}

/* Reveal on scroll */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity .7s cubic-bezier(.25,.46,.45,.94), transform .7s cubic-bezier(.25,.46,.45,.94);
  will-change: opacity, transform;
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

.section-icon {
  display: block;
  width: 96px;
  height: 96px;
  margin: 0 auto 1.5rem;
}

/* Nav */
.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--nav-bg);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  transition: box-shadow .3s ease, background .3s ease;
}

.nav--shadow {
  box-shadow: 0 4px 30px rgba(0,0,0,.15);
}

.nav__inner {
  display: flex;
  align-items: center;
  justify-content: flex-start;
  gap: 1.5rem;
  height: 68px;
}

.nav__brand {
  font-weight: 800;
  font-size: 1.25rem;
  background: linear-gradient(135deg, var(--text) 0%, var(--accent) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  transition: transform .2s ease;
}

.nav__brand:hover {
  transform: scale(1.02);
}

.nav__links {
  display: flex;
  gap: 2rem;
  list-style: none;
  margin-left: auto;
}

.nav__links a {
  position: relative;
  color: var(--text-muted);
  font-weight: 500;
  font-size: .95rem;
  padding: .25rem 0;
  transition: color .2s ease;
}

.nav__links a::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: 0;
  width: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  transition: width .25s ease;
  border-radius: 2px;
}

.nav__links a:hover,
.nav__links a:focus {
  color: var(--text);
}

.nav__links a:hover::after,
.nav__links a:focus::after {
  width: 100%;
}

.nav__toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  flex-direction: column;
  gap: 5px;
}

.nav__toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--text);
  transition: transform .25s ease, opacity .25s ease;
}

.nav__toggle[aria-expanded="true"] span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav__toggle[aria-expanded="true"] span:nth-child(2) {
  opacity: 0;
}

.nav__toggle[aria-expanded="true"] span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

.theme-toggle {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: var(--radius);
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: border-color .2s ease, transform .2s ease, box-shadow .2s ease;
}

.theme-toggle:hover {
  border-color: var(--accent);
  transform: translateY(-2px) rotate(8deg);
  box-shadow: 0 0 18px rgba(56,189,248,.25);
}

.theme-icon {
  display: none;
}

html[data-theme="dark"] .theme-icon--sun,
html[data-theme="light"] .theme-icon--moon {
  display: block;
  animation: popIn .3s ease;
}

/* Hero */
.hero {
  position: relative;
  padding: 9rem 0 7rem;
  text-align: center;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  inset: -50%;
  background:
    radial-gradient(circle at 20% 20%, rgba(56,189,248,.18), transparent 28%),
    radial-gradient(circle at 80% 10%, rgba(129,140,248,.14), transparent 28%),
    radial-gradient(circle at 50% 90%, rgba(56,189,248,.10), transparent 30%);
  z-index: -1;
  animation: float 14s ease-in-out infinite alternate;
}

.hero__content > * {
  opacity: 0;
  transform: translateY(24px);
  animation: fadeInUp .7s cubic-bezier(.25,.46,.45,.94) forwards;
}

.hero__content > *:nth-child(1) { animation-delay: .05s; }
.hero__content > *:nth-child(2) { animation-delay: .12s; }
.hero__content > *:nth-child(3) { animation-delay: .2s; }
.hero__content > *:nth-child(4) { animation-delay: .28s; }
.hero__content > *:nth-child(5) { animation-delay: .36s; }
.hero__content > *:nth-child(6) { animation-delay: .44s; }

.hero__greeting {
  color: var(--accent);
  font-weight: 700;
  letter-spacing: .08em;
  text-transform: uppercase;
  font-size: .85rem;
  margin-bottom: .75rem;
}

.hero__title {
  font-size: clamp(2.8rem, 7vw, 5rem);
  font-weight: 900;
  line-height: 1.05;
  margin-bottom: .5rem;
  background: linear-gradient(135deg, #fff 0%, var(--accent) 45%, var(--accent-2) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.hero__role {
  font-size: 1.6rem;
  color: var(--accent-2);
  font-weight: 600;
  margin-bottom: 1.5rem;
}

.hero__avatar {
  width: 150px;
  height: 150px;
  border-radius: 50%;
  object-fit: cover;
  border: 4px solid rgba(56,189,248,.4);
  box-shadow: 0 0 0 6px rgba(56,189,248,.12), 0 20px 40px rgba(0,0,0,.25);
  margin-bottom: 1.5rem;
  transition: transform .3s ease, box-shadow .3s ease;
  animation:
    fadeInUp .7s .12s cubic-bezier(.25,.46,.45,.94) forwards,
    floatAvatar 6s .85s ease-in-out infinite;
}

.hero__avatar:hover {
  transform: scale(1.05);
  box-shadow: 0 0 0 8px rgba(56,189,248,.18), 0 25px 50px rgba(0,0,0,.3);
}

.hero__summary {
  max-width: 680px;
  margin: 0 auto 2rem;
  color: var(--text-muted);
  font-size: 1.15rem;
  line-height: 1.7;
}

.hero__actions {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}

/* Buttons */
.btn {
  position: relative;
  display: inline-flex;
  align-items: center;
  padding: .9rem 1.8rem;
  border-radius: var(--radius);
  font-weight: 700;
  overflow: hidden;
  transition: transform .2s ease, box-shadow .2s ease;
  z-index: 1;
}

.btn::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(120deg, rgba(255,255,255,0) 0%, rgba(255,255,255,.2) 50%, rgba(255,255,255,0) 100%);
  transform: translateX(-100%);
  transition: transform .5s ease;
  z-index: -1;
}

.btn:hover {
  transform: translateY(-3px);
  text-decoration: none;
}

.btn:hover::before {
  transform: translateX(100%);
}

.btn--primary {
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: #ffffff;
  box-shadow: 0 8px 24px rgba(56,189,248,.25);
}

.btn--primary:hover {
  box-shadow: 0 12px 32px rgba(56,189,248,.4);
}

.btn--secondary {
  background: var(--bg-elevated);
  color: var(--text);
  border: 1px solid var(--border);
}

.btn--secondary:hover {
  border-color: var(--accent);
}

/* Sections */
.section {
  padding: 5rem 0;
}

.section + .section--alt {
  padding-top: 2.5rem;
}

.section--alt {
  background: var(--bg-elevated);
  position: relative;
}

.section__title {
  font-size: 2.2rem;
  font-weight: 800;
  margin-bottom: .5rem;
  text-align: center;
  background: linear-gradient(135deg, var(--text), var(--accent));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.section__subtitle {
  color: var(--text-muted);
  text-align: center;
  margin-bottom: 2.5rem;
  font-size: 1.05rem;
}

/* Filters */
.filters {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: .55rem;
  margin-bottom: 2rem;
}

.filter-btn {
  background: transparent;
  color: var(--text-muted);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: .5rem 1.1rem;
  cursor: pointer;
  font-size: .85rem;
  font-weight: 500;
  transition: all .2s ease;
}

.filter-btn:hover,
.filter-btn.active {
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  border-color: transparent;
  color: #ffffff;
  font-weight: 600;
  box-shadow: 0 4px 14px rgba(56,189,248,.25);
}

/* Projects */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.75rem;
  perspective: 1000px;
}

.project-card {
  position: relative;
  background: linear-gradient(145deg, var(--bg-elevated), rgba(56,189,248,.03));
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.75rem;
  display: flex;
  flex-direction: column;
  transform: translateZ(0);
  transition: transform .35s cubic-bezier(.25,.46,.45,.94), box-shadow .35s ease, border-color .35s ease;
  opacity: 0;
  animation: fadeInUp .55s cubic-bezier(.25,.46,.45,.94) forwards;
}

.project-card:hover {
  transform: translateY(-8px) translateZ(0);
  border-color: rgba(56,189,248,.5);
  box-shadow: 0 20px 45px rgba(0,0,0,.2), 0 0 25px rgba(56,189,248,.12);
}

.project-card__category {
  font-size: .75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .07em;
  color: var(--accent);
  margin-bottom: .6rem;
}

.project-card__title {
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: .6rem;
}

.project-card__desc {
  color: var(--text-muted);
  font-size: .95rem;
  line-height: 1.6;
  margin-bottom: 1.25rem;
  flex: 1;
}

.project-card__tags {
  display: flex;
  flex-wrap: wrap;
  gap: .4rem;
  margin-bottom: 1.25rem;
}

.project-card__tags span {
  background: rgba(56,189,248,.1);
  color: var(--accent);
  padding: .2rem .6rem;
  border-radius: 999px;
  font-size: .75rem;
  font-weight: 500;
}

.project-card__link {
  align-self: flex-start;
  font-size: .9rem;
  font-weight: 700;
  display: inline-flex;
  align-items: center;
  gap: .4rem;
  transition: gap .2s ease, color .2s ease;
}

.project-card__link:hover {
  gap: .7rem;
  color: var(--text);
}

/* Skills */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.5rem;
}

.skill-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.75rem;
  transition: transform .3s ease, border-color .3s ease, box-shadow .3s ease;
}

.skill-card:hover {
  transform: translateY(-4px);
  border-color: var(--accent);
  box-shadow: 0 10px 30px rgba(0,0,0,.15);
}

.skill-card h3 {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: .5rem;
  color: var(--accent);
}

.skill-card p {
  color: var(--text-muted);
  font-size: .95rem;
}

/* Contact */
.contact__inner {
  text-align: center;
}

.contact__links {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 1.25rem;
  margin-top: 1.5rem;
}

.contact__link {
  display: inline-flex;
  align-items: center;
  gap: .6rem;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  padding: .95rem 1.35rem;
  border-radius: var(--radius);
  color: var(--text);
  font-weight: 500;
  transition: border-color .25s ease, transform .25s ease, box-shadow .25s ease;
}

.contact__link:hover {
  border-color: var(--accent);
  transform: translateY(-3px);
  text-decoration: none;
  box-shadow: 0 10px 28px rgba(0,0,0,.18);
}

/* Certifications */
.certifications-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
}

.certification-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  opacity: 0;
  animation: fadeInUp .55s cubic-bezier(.25,.46,.45,.94) forwards;
  transition: transform .3s ease, border-color .3s ease, box-shadow .3s ease;
}

.certification-card:hover {
  transform: translateY(-4px);
  border-color: var(--accent);
  box-shadow: 0 10px 30px rgba(0,0,0,.15);
}

.certification-card h3 {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: .4rem;
  color: var(--text);
}

.certification-card__issuer {
  color: var(--accent);
  font-weight: 600;
  font-size: .9rem;
  margin-bottom: .25rem;
}

.certification-card__date {
  color: var(--text-muted);
  font-size: .85rem;
  margin-bottom: 1rem;
}

.certification-card__link {
  font-size: .9rem;
  font-weight: 600;
}

/* Footer */
.footer {
  padding: 2.5rem 0;
  border-top: 1px solid var(--border);
  text-align: center;
  color: var(--text-muted);
  font-size: .9rem;
}

/* Language chart */
.language-chart {
  max-width: 720px;
  margin: 0 auto;
}

.language-row {
  display: grid;
  grid-template-columns: 140px 1fr 60px;
  align-items: center;
  gap: 1rem;
  margin-bottom: 1.1rem;
  opacity: 0;
  transform: translateX(-20px);
  animation: slideIn .6s cubic-bezier(.25,.46,.45,.94) forwards;
}

.language-name {
  font-weight: 600;
  font-size: .95rem;
  text-align: right;
  color: var(--text);
}

.language-track {
  background: var(--border);
  border-radius: var(--radius);
  height: 26px;
  overflow: hidden;
}

.language-bar {
  height: 100%;
  border-radius: var(--radius);
  transition: width .9s cubic-bezier(.25,.46,.45,.94);
  box-shadow: inset 0 0 10px rgba(255,255,255,.12);
}

.language-percent {
  font-weight: 700;
  font-size: .95rem;
  color: var(--text-muted);
  text-align: right;
}

/* Keyframes */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(24px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes slideIn {
  from { opacity: 0; transform: translateX(-20px); }
  to { opacity: 1; transform: translateX(0); }
}

@keyframes float {
  from { transform: translate(0, 0) scale(1); }
  to { transform: translate(-2%, 2%) scale(1.05); }
}

@keyframes floatAvatar {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-8px); }
}

@keyframes popIn {
  from { opacity: 0; transform: scale(.6) rotate(-20deg); }
  to { opacity: 1; transform: scale(1) rotate(0); }
}

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: .01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .01ms !important;
  }
}

/* Mobile */
@media (max-width: 700px) {
  .nav__links {
    display: none;
    position: absolute;
    top: 68px;
    left: 0;
    right: 0;
    background: var(--bg-elevated);
    flex-direction: column;
    padding: 1rem;
    border-bottom: 1px solid var(--border);
    gap: 1rem;
    margin-left: 0;
  }

  .nav__links.open {
    display: flex;
  }

  .nav__toggle {
    display: flex;
    order: -1;
  }

  .theme-toggle {
    margin-left: auto;
  }

  .hero {
    padding: 6rem 0 4.5rem;
  }

  .hero__title {
    font-size: clamp(2.2rem, 8vw, 3.5rem);
  }

  .filters {
    gap: .35rem;
  }

  .filter-btn {
    padding: .4rem .8rem;
    font-size: .8rem;
  }

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

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

  .language-row {
    grid-template-columns: 90px 1fr 48px;
    gap: .65rem;
  }

  .language-name,
  .language-percent {
    font-size: .85rem;
  }
}