:root {
  --dark-navy: #0a192f;
  --navy: #112240;
  --light-navy: #233554;
  --slate: #8892b0;
  --light-slate: #a8b2d1;
  --lightest-slate: #ccd6f6;
  --white: #e6f1ff;
  --green: #64ffda;
  --green-tint: rgba(100, 255, 218, 0.1);
  --font-sans: 'Inter', -apple-system, 'PingFang SC', 'Microsoft YaHei', system-ui, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Courier New', monospace;
  --fz-xs: 12px;
  --fz-sm: 13px;
  --fz-md: 16px;
  --fz-lg: 20px;
  --fz-xl: 24px;
  --fz-xxl: 32px;
  --fz-heading: 50px;
  --sidebar-width: 200px;
  --transition: 0.25s cubic-bezier(0.645, 0.045, 0.355, 1);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 20px;
}

body {
  font-family: var(--font-sans);
  font-size: var(--fz-md);
  line-height: 1.6;
  color: var(--slate);
  background-color: var(--dark-navy);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

::selection {
  background: var(--green);
  color: var(--dark-navy);
}

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

a:hover {
  color: var(--green);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

ul {
  list-style: none;
}

strong {
  color: var(--lightest-slate);
  font-weight: 600;
}

.mono {
  font-family: var(--font-mono);
  font-size: var(--fz-sm);
}

.skip-link {
  position: absolute;
  top: -100%;
  left: 0;
  padding: 10px 20px;
  background: var(--green);
  color: var(--dark-navy);
  z-index: 1000;
  font-weight: 700;
}

.skip-link:focus {
  top: 0;
}

/* ========== Sidebar ========== */
.sidebar {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--sidebar-width);
  height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 40px 20px;
  z-index: 10;
}

.sidebar__logo a {
  display: block;
  color: var(--green);
  transition: transform var(--transition);
}

.sidebar__logo a:hover {
  transform: rotate(-10deg) scale(1.1);
  text-decoration: none;
}

.sidebar__nav {
  display: flex;
  flex-direction: column;
  gap: 4px;
  margin-top: auto;
  margin-bottom: auto;
}

.nav-link {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 6px 12px;
  font-family: var(--font-mono);
  font-size: var(--fz-xs);
  color: var(--slate);
  border-radius: 4px;
  transition: all var(--transition);
  white-space: nowrap;
}

.nav-link:hover {
  color: var(--green);
  text-decoration: none;
  background: var(--green-tint);
  transform: translateX(3px);
}

.nav-link.active {
  color: var(--green);
}

.nav-number {
  color: var(--green);
  font-size: var(--fz-xs);
}

.sidebar__social {
  display: flex;
  gap: 16px;
  margin-top: auto;
}

.sidebar__social a {
  color: var(--slate);
  width: 20px;
  height: 20px;
  transition: color var(--transition), transform var(--transition);
}

.sidebar__social a:hover {
  color: var(--green);
  transform: translateY(-3px);
  text-decoration: none;
}

.sidebar__social svg {
  width: 20px;
  height: 20px;
}

/* ========== Main Content ========== */
.main {
  margin-left: var(--sidebar-width);
  padding: 0 50px 100px;
  max-width: 1000px;
}

.section {
  padding: 100px 0;
  min-height: 60vh;
}

.section:last-of-type {
  min-height: auto;
}

.section__greeting {
  color: var(--green);
  margin-bottom: 16px;
  font-size: var(--fz-md);
}

.section__name {
  font-size: clamp(40px, 8vw, var(--fz-heading));
  font-weight: 700;
  color: var(--lightest-slate);
  line-height: 1.1;
  margin-bottom: 8px;
}

.section__subtitle {
  font-size: clamp(28px, 5vw, var(--fz-xxl));
  font-weight: 700;
  color: var(--slate);
  line-height: 1.1;
  margin-bottom: 24px;
}

.section__desc {
  max-width: 540px;
  margin-bottom: 32px;
}

.section__title {
  font-size: var(--fz-xxl);
  font-weight: 700;
  color: var(--lightest-slate);
  margin-bottom: 40px;
  display: flex;
  align-items: center;
  gap: 12px;
  white-space: nowrap;
}

.section__title .mono {
  color: var(--green);
  font-size: var(--fz-lg);
}

.section__title::after {
  content: '';
  display: block;
  height: 1px;
  width: 300px;
  background-color: var(--light-navy);
  flex-shrink: 0;
}

.section__tags-label {
  margin-bottom: 16px;
  font-size: var(--fz-md);
}

/* ========== Tech Tags ========== */
.tech-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(140px, 200px));
  gap: 4px 16px;
  font-family: var(--font-mono);
  font-size: var(--fz-xs);
}

.tech-list li::before {
  content: '▹ ';
  color: var(--green);
}

/* ========== Experience ========== */
.experience__container {
  display: flex;
  gap: 20px;
}

.experience__tabs {
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 140px;
}

.exp-tab {
  background: transparent;
  border: none;
  border-left: 2px solid var(--light-navy);
  padding: 10px 16px 10px 20px;
  text-align: left;
  font-family: var(--font-mono);
  font-size: var(--fz-xs);
  color: var(--slate);
  cursor: pointer;
  transition: all var(--transition);
  white-space: nowrap;
}

.exp-tab:hover {
  color: var(--green);
  background: var(--green-tint);
}

.exp-tab.active {
  color: var(--green);
  border-left-color: var(--green);
  background: var(--green-tint);
}

.experience__content {
  flex: 1;
  position: relative;
}

.exp-panel {
  display: none;
  animation: fadeIn 0.3s ease;
}

.exp-panel.active {
  display: block;
}

.exp-title {
  font-size: var(--fz-lg);
  color: var(--lightest-slate);
  margin-bottom: 4px;
  font-weight: 600;
}

.exp-company {
  color: var(--green);
  font-weight: 500;
}

.exp-date {
  font-family: var(--font-mono);
  font-size: var(--fz-xs);
  color: var(--slate);
  margin-bottom: 20px;
}

.exp-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.exp-list li {
  padding-left: 20px;
  position: relative;
}

.exp-list li::before {
  content: '▹';
  position: absolute;
  left: 0;
  color: var(--green);
}

/* ========== Projects ========== */
.projects__grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
  margin-bottom: 40px;
}

.project-card {
  background: var(--navy);
  border-radius: 8px;
  padding: 28px;
  transition: transform var(--transition), box-shadow var(--transition);
  display: flex;
  flex-direction: column;
  cursor: default;
  position: relative;
}

.project-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 10px 30px -15px rgba(2, 12, 27, 0.7);
}

.project-card__header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 24px;
}

.project-card__icon {
  width: 40px;
  height: 40px;
  color: var(--green);
}

.project-card__links {
  display: flex;
  gap: 12px;
}

.project-link {
  color: var(--slate);
  width: 20px;
  height: 20px;
  transition: color var(--transition);
}

.project-link:hover {
  color: var(--green);
  text-decoration: none;
}

.project-link svg {
  width: 20px;
  height: 20px;
}

.project-card__title {
  font-size: var(--fz-lg);
  color: var(--lightest-slate);
  margin-bottom: 12px;
  transition: color var(--transition);
  font-weight: 700;
}

.project-card:hover .project-card__title {
  color: var(--green);
}

.project-card__desc {
  font-size: var(--fz-sm);
  flex: 1;
  margin-bottom: 16px;
}

.project-card__tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: var(--fz-xs);
}

.project-card__tags li {
  color: var(--green);
  background: var(--green-tint);
  padding: 2px 8px;
  border-radius: 3px;
}

.other-heading {
  font-size: var(--fz-lg);
  color: var(--lightest-slate);
  margin-bottom: 24px;
  text-align: center;
}

.projects__small-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}

.project-card.small {
  padding: 24px;
}

.project-card.small .project-card__title {
  font-size: var(--fz-md);
}

/* ========== Contact ========== */
.contact {
  text-align: center;
  max-width: 540px;
  margin: 0 auto;
}

.contact__heading {
  font-size: clamp(32px, 5vw, var(--fz-heading));
  color: var(--lightest-slate);
  font-weight: 700;
  margin-bottom: 16px;
}

.contact__desc {
  margin-bottom: 40px;
}

.contact__btn {
  display: inline-block;
  padding: 16px 40px;
  border: 1px solid var(--green);
  border-radius: 4px;
  font-family: var(--font-mono);
  font-size: var(--fz-sm);
  color: var(--green);
  transition: all var(--transition);
}

.contact__btn:hover {
  background: var(--green-tint);
  text-decoration: none;
  transform: translateY(-2px);
}

/* ========== Footer ========== */
.footer {
  text-align: center;
  padding: 20px;
  font-family: var(--font-mono);
  font-size: var(--fz-xs);
  color: var(--slate);
  margin-left: var(--sidebar-width);
}

.footer a {
  color: var(--slate);
}

.footer a:hover {
  color: var(--green);
}

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

.fade-in {
  opacity: 0;
  transform: translateY(40px);
  transition: opacity 0.6s ease-out, transform 0.6s ease-out;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Staggered animation delays for child elements */
.fade-in.visible .section__greeting { animation: fadeInUp 0.5s ease-out 0.1s both; }
.fade-in.visible .section__name { animation: fadeInUp 0.5s ease-out 0.2s both; }
.fade-in.visible .section__subtitle { animation: fadeInUp 0.5s ease-out 0.3s both; }
.fade-in.visible .section__desc { animation: fadeInUp 0.5s ease-out 0.4s both; }
.fade-in.visible .section__tags { animation: fadeInUp 0.5s ease-out 0.5s both; }

@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ========== Scrollbar ========== */
::-webkit-scrollbar {
  width: 8px;
}

::-webkit-scrollbar-track {
  background: var(--dark-navy);
}

::-webkit-scrollbar-thumb {
  background: var(--light-navy);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--slate);
}

/* ========== Mobile Menu ========== */
.menu-btn {
  display: none;
  position: fixed;
  top: 20px;
  right: 20px;
  z-index: 100;
  background: transparent;
  border: none;
  width: 36px;
  height: 30px;
  cursor: pointer;
  flex-direction: column;
  justify-content: space-between;
}

.menu-btn span {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--green);
  border-radius: 2px;
  transition: all var(--transition);
}

.menu-btn.open span:nth-child(1) {
  transform: translateY(14px) rotate(45deg);
}

.menu-btn.open span:nth-child(2) {
  opacity: 0;
}

.menu-btn.open span:nth-child(3) {
  transform: translateY(-14px) rotate(-45deg);
}

.mobile-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(10, 25, 47, 0.85);
  z-index: 9;
  backdrop-filter: blur(4px);
}

.mobile-overlay.show {
  display: block;
}

/* ========== Responsive ========== */
@media (max-width: 1080px) {
  .projects__grid {
    grid-template-columns: 1fr;
  }
  .projects__small-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  :root {
    --sidebar-width: 0px;
  }

  .sidebar {
    position: fixed;
    top: 0;
    right: -300px;
    left: auto;
    width: min(280px, 80vw);
    height: 100vh;
    background: var(--navy);
    padding: 80px 30px 40px;
    align-items: flex-start;
    transition: right var(--transition);
    box-shadow: -10px 0 30px -15px rgba(2, 12, 27, 0.7);
  }

  .sidebar.open {
    right: 0;
  }

  .sidebar__logo {
    display: none;
  }

  .sidebar__nav {
    margin: 0;
    gap: 8px;
  }

  .nav-link {
    font-size: var(--fz-md);
    padding: 10px 16px;
  }

  .sidebar__social {
    margin-top: 40px;
    flex-direction: row;
    gap: 20px;
  }

  .sidebar__social svg {
    width: 24px;
    height: 24px;
  }

  .menu-btn {
    display: flex;
  }

  .main {
    margin-left: 0;
    padding: 0 24px 80px;
  }

  .section {
    padding: 60px 0;
  }

  .section__title::after {
    width: 100px;
  }

  .experience__container {
    flex-direction: column;
  }

  .experience__tabs {
    flex-direction: row;
    overflow-x: auto;
    min-width: unset;
    gap: 0;
    margin-bottom: 20px;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
  }

  .experience__tabs::-webkit-scrollbar {
    display: none;
  }

  .exp-tab {
    border-left: none;
    border-bottom: 2px solid var(--light-navy);
    padding: 8px 14px;
    white-space: nowrap;
  }

  .exp-tab.active {
    border-left: none;
    border-bottom-color: var(--green);
  }

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

  .footer {
    margin-left: 0;
  }
}

@media (max-width: 480px) {
  .section__name {
    font-size: 32px;
  }

  .section__subtitle {
    font-size: 22px;
  }

  .tech-list {
    grid-template-columns: 1fr;
  }
}