/* ============================================================
   ROOT VARIABLES — THEME SYSTEM
   ============================================================ */
:root {
  /* Light Mode — "Minimal Engineering" */
  --bg: #FFFFFF;
  --bg-alt: #FBFCFD;
  --primary: #2563EB;
  --secondary: #6B7280;
  --card: #F8FAFC;
  --text: #111827;
  --text-soft: #4B5563;
  --border: #E5E7EB;
  --accent: #3B82F6;
  --shadow: rgba(17, 24, 39, 0.08);
  --shadow-strong: rgba(17, 24, 39, 0.14);
  --glow: transparent;
  --ring-track: #E5E7EB;

  --font-display: "Poppins", "Inter", sans-serif;
  --font-body: "Inter", "Poppins", sans-serif;

  --radius-sm: 10px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --transition: 300ms ease-in-out;
  --max-width: 1200px;
}

[data-theme="dark"] {
  /* Dark Mode — "Cyber Mechatronics" */
  --bg: #050816;
  --bg-alt: #080B1A;
  --primary: #00E5FF;
  --secondary: #00FF88;
  --card: #0F172A;
  --text: #F8FAFC;
  --text-soft: #94A3B8;
  --border: rgba(255, 255, 255, 0.08);
  --accent: #00E5FF;
  --shadow: rgba(0, 229, 255, 0.06);
  --shadow-strong: rgba(0, 229, 255, 0.16);
  --glow: rgba(0, 229, 255, 0.35);
  --ring-track: rgba(255, 255, 255, 0.08);
}

/* ============================================================
   RESET & BASE
   ============================================================ */
* { margin: 0; padding: 0; box-sizing: border-box; }

html {
  scroll-behavior: smooth;
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

body {
  font-family: var(--font-body);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  transition: background var(--transition), color var(--transition);
  overflow-x: hidden;
}

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 600;
  line-height: 1.2;
}

a { text-decoration: none; color: inherit; }
ul { list-style: none; }
img { max-width: 100%; display: block; }
button { font-family: inherit; cursor: pointer; border: none; background: none; }

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 32px;
}

.section {
  position: relative;
  padding: 120px 0;
}

/* Focus visibility for accessibility */
a:focus-visible,
button:focus-visible {
  outline: 2px solid var(--primary);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ============================================================
   SCROLL PROGRESS BAR
   ============================================================ */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  height: 3px;
  width: 0%;
  background: linear-gradient(90deg, var(--primary), var(--secondary));
  z-index: 1100;
  transition: width 100ms ease-out;
}

[data-theme="dark"] .scroll-progress {
  box-shadow: 0 0 8px var(--glow);
}

/* ============================================================
   NAVBAR
   ============================================================ */
.navbar {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  transition: background var(--transition), border-color var(--transition);
}

.nav-container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 18px 32px;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 24px;
}

.nav-container .logo { justify-self: start; }
.nav-container .nav-links { justify-self: center; }
.nav-container .nav-actions { justify-self: end; }

.logo {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.25rem;
  letter-spacing: 0.5px;
}

.logo-dot { color: var(--primary); }

.nav-links {
  display: flex;
  gap: 28px;
}

.nav-link {
  position: relative;
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--text-soft);
  padding: 6px 2px;
  transition: color var(--transition);
}

.nav-link::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -4px;
  width: 0%;
  height: 2px;
  background: var(--primary);
  transition: width var(--transition);
  border-radius: 2px;
}

.nav-link:hover,
.nav-link.active {
  color: var(--text);
}

.nav-link.active::after,
.nav-link:hover::after {
  width: 100%;
}

[data-theme="dark"] .nav-link.active::after {
  box-shadow: 0 0 8px var(--glow);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 14px;
  position: absolute;
}

/* Theme toggle button */
.theme-toggle {
  position: relative;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--card);
  border: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background var(--transition), border-color var(--transition), transform var(--transition);
}

.theme-toggle:hover {
  transform: rotate(20deg) scale(1.05);
}

.theme-toggle i {
  position: absolute;
  font-size: 1rem;
  transition: opacity var(--transition), transform var(--transition);
}

.icon-sun { color: #F59E0B; opacity: 1; transform: scale(1) rotate(0deg); }
.icon-moon { color: var(--primary); opacity: 0; transform: scale(0.4) rotate(90deg); }

[data-theme="dark"] .icon-sun { opacity: 0; transform: scale(0.4) rotate(-90deg); }
[data-theme="dark"] .icon-moon { opacity: 1; transform: scale(1) rotate(0deg); }

[data-theme="dark"] .theme-toggle {
  box-shadow: 0 0 14px var(--glow);
}

/* Language toggle */
.lang-toggle {
  display: flex;
  align-items: center;
  gap: 8px;
  height: 44px;
  padding: 0 16px;
  border-radius: 999px;
  background: var(--card);
  border: 1px solid var(--border);
  color: var(--text);
  font-weight: 600;
  font-size: 0.85rem;
  transition: border-color var(--transition), transform var(--transition), box-shadow var(--transition);
}

.lang-toggle:hover {
  border-color: var(--primary);
  transform: translateY(-2px);
}

[data-theme="dark"] .lang-toggle:hover {
  box-shadow: 0 0 14px var(--glow);
}

.lang-flag {
  width: 20px;
  height: 14px;
  object-fit: cover;
  display: block;
  border-radius: 2px;
  box-shadow: 0 0 0 1px rgba(0, 0, 0, 0.08);
}

.lang-text {
  letter-spacing: 0.5px;
}

/* Fade transition applied globally while translations swap */
body.lang-transition [data-i18n],
body.lang-transition .lang-text,
body.lang-transition .lang-flag {
  transition: opacity 150ms ease;
  opacity: 0;
}

/* Hamburger (mobile) */
.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  width: 26px;
}

.hamburger span {
  height: 2px;
  width: 100%;
  background: var(--text);
  border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition);
}

.hamburger.active span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.hamburger.active span:nth-child(2) { opacity: 0; }
.hamburger.active span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ============================================================
   FADE-UP ANIMATION (Intersection Observer driven)
   ============================================================ */
.fade-up {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.7s ease, transform 0.7s ease;
  transition-delay: var(--delay, 0s);
}

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

/* ============================================================
   HERO
   ============================================================ */
.hero {
  min-height: 92vh;
  display: flex;
  align-items: center;
  padding: 80px 0;
  overflow: hidden;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 48px;
  align-items: center;
  position: relative;
  z-index: 2;
}

.hero-greeting {
  font-size: 1.1rem;
  color: var(--primary);
  font-weight: 500;
  margin-bottom: 8px;
}

.hero-name {
  font-size: clamp(3rem, 7vw, 5rem);
  font-weight: 700;
  letter-spacing: 1px;
  margin-bottom: 8px;
  background: linear-gradient(120deg, var(--text), var(--primary));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-role {
  font-size: clamp(1.15rem, 2.4vw, 1.5rem);
  font-weight: 600;
  color: var(--text-soft);
  margin-bottom: 20px;
}

.hero-desc {
  max-width: 480px;
  color: var(--text-soft);
  font-size: 1.02rem;
  margin-bottom: 32px;
}

.hero-buttons {
  display: flex;
  gap: 16px;
  margin-bottom: 36px;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 30px;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 0.95rem;
  transition: transform var(--transition), box-shadow var(--transition), background var(--transition), border-color var(--transition);
}

.btn-primary {
  background: var(--primary);
  color: #ffffff;
}

[data-theme="dark"] .btn-primary {
  color: #050816;
}

.btn-primary:hover {
  transform: translateY(-3px);
  box-shadow: 0 10px 24px var(--shadow-strong);
}

[data-theme="dark"] .btn-primary:hover {
  box-shadow: 0 0 22px var(--glow);
}

.btn-outline {
  border: 1.5px solid var(--border);
  color: var(--text);
}

.btn-outline:hover {
  border-color: var(--primary);
  transform: translateY(-3px);
  color: var(--primary);
}

.social-icons {
  display: flex;
  gap: 14px;
}

.social-icon {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--card);
  border: 1px solid var(--border);
  color: var(--text-soft);
  transition: transform var(--transition), color var(--transition), border-color var(--transition);
}

.social-icon:hover {
  transform: translateY(-4px);
  color: var(--primary);
  border-color: var(--primary);
}

/* Hero image */
.hero-image-wrap {
  display: flex;
  justify-content: center;
}

.hero-ring {
  position: relative;
  width: min(360px, 80vw);
  height: min(360px, 80vw);
  border-radius: 50%;
  border: 2px solid var(--border);
  padding: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: border-color var(--transition), box-shadow var(--transition);
}

[data-theme="dark"] .hero-ring {
  border-color: var(--primary);
  box-shadow: 0 0 30px var(--glow), inset 0 0 30px rgba(0, 229, 255, 0.15);
  animation: pulse-ring 3.5s ease-in-out infinite;
}

@keyframes pulse-ring {
  0%, 100% { box-shadow: 0 0 24px var(--glow), inset 0 0 20px rgba(0, 229, 255, 0.12); }
  50% { box-shadow: 0 0 42px var(--glow), inset 0 0 34px rgba(0, 229, 255, 0.22); }
}

.hero-image {
  width: 100%;
  height: 100%;
  border-radius: 50%;
  object-fit: cover;
}

/* Hero decoration */
.hero-decoration {
  position: absolute;
  inset: 0;
  z-index: 0;
  pointer-events: none;
}

.grid-pattern {
  position: absolute;
  inset: 0;
  opacity: 0;
  background-image:
    linear-gradient(var(--primary) 1px, transparent 1px),
    linear-gradient(90deg, var(--primary) 1px, transparent 1px);
  background-size: 48px 48px;
}

[data-theme="dark"] .grid-pattern { opacity: 0.06; }

.circuit-line {
  position: absolute;
  background: var(--primary);
  opacity: 0;
}

[data-theme="dark"] .circuit-line { opacity: 0.25; }

.circuit-line--1 { top: 18%; left: 0; width: 30%; height: 1px; }
.circuit-line--2 { top: 18%; left: 30%; width: 1px; height: 22%; }
.circuit-line--3 { bottom: 12%; right: 0; width: 22%; height: 1px; }

.geo-shape {
  position: absolute;
  width: 220px;
  height: 220px;
  fill: none;
  stroke: var(--secondary);
  stroke-width: 1;
  opacity: 0;
}

[data-theme="light"] .geo-shape,
:root .geo-shape { opacity: 0.08; }

[data-theme="dark"] .geo-shape { opacity: 0.08; stroke: var(--primary); }

.geo-shape--1 { top: -40px; right: -40px; }
.geo-shape--2 { bottom: -20px; left: -60px; width: 160px; height: 160px; }

.particle-canvas {
  position: absolute;
  inset: 0;
  z-index: 1;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.6s ease;
}

[data-theme="dark"] .particle-canvas { opacity: 1; }

.scroll-hint {
  position: absolute;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%);
  color: var(--text-soft);
  font-size: 1.1rem;
  animation: bob 2s ease-in-out infinite;
  z-index: 2;
}

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

/* ============================================================
   SECTION HEADERS (shared)
   ============================================================ */
.section-header {
  text-align: center;
  max-width: 720px;
  margin: 0 auto 56px;
}

.section-eyebrow {
  color: var(--primary);
  font-weight: 600;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 2px;
  margin-bottom: 10px;
}

.section-title {
  font-size: clamp(2rem, 4vw, 2.6rem);
  margin-bottom: 16px;
}

.section-lead {
  color: var(--text-soft);
  font-size: 1.05rem;
}

/* ============================================================
   ABOUT
   ============================================================ */
.about-cards {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.info-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 32px 26px;
  transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
}

.info-card:hover {
  transform: translateY(-8px);
  box-shadow: 0 16px 32px var(--shadow);
  border-color: var(--primary);
}

[data-theme="dark"] .info-card {
  backdrop-filter: blur(10px);
  background: color-mix(in srgb, var(--card) 70%, transparent);
}

[data-theme="dark"] .info-card:hover {
  box-shadow: 0 0 26px var(--shadow-strong);
}

.info-icon {
  width: 52px;
  height: 52px;
  border-radius: var(--radius-sm);
  background: color-mix(in srgb, var(--primary) 12%, transparent);
  color: var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  margin-bottom: 18px;
}

.info-card h3 {
  font-size: 1.15rem;
  margin-bottom: 10px;
}

.info-card p {
  color: var(--text-soft);
  font-size: 0.95rem;
}

.interest-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.interest-list li {
  font-size: 0.92rem;
  color: var(--text-soft);
  padding-left: 18px;
  position: relative;
}

.interest-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 8px;
  width: 8px;
  height: 8px;
  border-radius: 2px;
  background: var(--primary);
}

/* ============================================================
   PROJECTS
   ============================================================ */
.project-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.project-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
}

.project-card:hover {
  transform: translateY(-10px);
  box-shadow: 0 20px 40px var(--shadow);
  border-color: var(--primary);
}

[data-theme="dark"] .project-card:hover {
  box-shadow: 0 0 28px var(--shadow-strong);
}

.project-image {
  position: relative;
  aspect-ratio: 3 / 2;
  overflow: hidden;
  display: block;
}

.project-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.5s ease;
}

.project-card:hover .project-image img {
  transform: scale(1.06);
}

/* Clickable images that link through to the gallery page */
.clickable-image {
  cursor: pointer;
}

.image-overlay {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: color-mix(in srgb, var(--bg) 55%, transparent);
  backdrop-filter: blur(2px);
  color: var(--text);
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1rem;
  letter-spacing: 0.5px;
  opacity: 0;
  transition: opacity var(--transition);
  z-index: 2;
}

[data-theme="dark"] .image-overlay {
  color: var(--primary);
  text-shadow: 0 0 12px var(--glow);
}

.clickable-image:hover .image-overlay,
.clickable-image:focus-visible .image-overlay {
  opacity: 1;
}

[data-theme="dark"] .clickable-image:hover img,
[data-theme="dark"] .clickable-image:focus-visible img {
  filter: brightness(1.05) drop-shadow(0 0 18px var(--glow));
}

.project-body {
  padding: 26px;
}

.project-body h3 {
  font-size: 1.2rem;
  margin-bottom: 10px;
}

.project-body p {
  color: var(--text-soft);
  font-size: 0.93rem;
  margin-bottom: 18px;
}

.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.tag {
  font-size: 0.75rem;
  font-weight: 500;
  padding: 6px 12px;
  border-radius: 999px;
  background: color-mix(in srgb, var(--primary) 10%, transparent);
  color: var(--primary);
  border: 1px solid color-mix(in srgb, var(--primary) 25%, transparent);
}

/* ============================================================
   SKILLS
   ============================================================ */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 32px;
}

.skill-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  position: relative;
}

.progress-ring {
  width: 140px;
  height: 140px;
  transform: rotate(-90deg);
}

.progress-ring__bg {
  fill: none;
  stroke: var(--ring-track);
  stroke-width: 10;
}

.progress-ring__fill {
  fill: none;
  stroke: var(--primary);
  stroke-width: 10;
  stroke-linecap: round;
  stroke-dasharray: 439.8;
  stroke-dashoffset: 439.8;
  transition: stroke-dashoffset 1.5s cubic-bezier(0.22, 1, 0.36, 1);
}

[data-theme="dark"] .progress-ring__fill {
  filter: drop-shadow(0 0 6px var(--glow));
}

.progress-value {
  position: absolute;
  margin-top: 54px;
  font-size: 1.3rem;
  font-weight: 700;
  font-family: var(--font-display);
}

.skill-label {
  margin-top: 46px;
  color: var(--text-soft);
  font-weight: 500;
  text-align: center;
}

/* ============================================================
   EXPERIENCE
   ============================================================ */
.experience-feature {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 56px;
  align-items: center;
}

.experience-image {
  position: relative;
  aspect-ratio: 1 / 1;
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--border);
}

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

.badge {
  position: absolute;
  bottom: 20px;
  left: 20px;
  background: color-mix(in srgb, var(--bg) 85%, transparent);
  backdrop-filter: blur(10px);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 14px 20px;
  display: flex;
  flex-direction: column;
  gap: 2px;
}

[data-theme="dark"] .badge {
  border-color: var(--primary);
  box-shadow: 0 0 20px var(--glow);
}

.badge-label {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  color: var(--text-soft);
}

.badge-year {
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--primary);
  font-family: var(--font-display);
}

.badge-title {
  font-size: 0.9rem;
  font-weight: 600;
}

.experience-text h3 {
  font-size: 1.5rem;
  margin-bottom: 20px;
}

.experience-text p {
  color: var(--text-soft);
  margin-bottom: 16px;
  font-size: 0.98rem;
}

/* ============================================================
   FOOTER
   ============================================================ */
.footer {
  border-top: 1px solid var(--border);
  padding: 72px 0 28px;
  background: var(--bg-alt);
  transition: border-color var(--transition), background var(--transition);
  margin-top: 40px;
}

[data-theme="dark"] .footer {
  border-top: 1px solid color-mix(in srgb, var(--primary) 30%, transparent);
  box-shadow: 0 -1px 30px var(--shadow);
}

.footer-main {
  text-align: center;
  margin-bottom: 40px;
}

.footer-main h2 {
  font-size: 2rem;
  margin-bottom: 12px;
}

.footer-main p {
  color: var(--text-soft);
  max-width: 460px;
  margin: 0 auto 28px;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 18px;
  flex-wrap: wrap;
}

.footer-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 22px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  font-weight: 500;
  font-size: 0.92rem;
  transition: transform var(--transition), border-color var(--transition), color var(--transition);
}

.footer-link:hover {
  transform: translateY(-3px);
  border-color: var(--primary);
  color: var(--primary);
}

.footer-bottom {
  text-align: center;
  padding-top: 28px;
  border-top: 1px solid var(--border);
  color: var(--text-soft);
  font-size: 0.85rem;
}

/* ============================================================
   RESPONSIVE — TABLET
   ============================================================ */
@media (max-width: 1024px) {
  .about-cards { grid-template-columns: repeat(2, 1fr); }
  .project-grid { grid-template-columns: 1fr; max-width: 560px; margin: 0 auto; }
  .experience-feature { grid-template-columns: 1fr; }
  .experience-image { max-width: 420px; margin: 0 auto; }
}

/* ============================================================
   RESPONSIVE — MOBILE
   ============================================================ */
@media (max-width: 768px) {
  .section { padding: 88px 0; }
  .container { padding: 0 20px; }

  .nav-links {
    position: fixed;
    width: 100%;
    top: 68px;
    left: 0;
    right: 0;
    flex-direction: column;
    background: var(--bg);
    border-bottom: 1px solid var(--border);
    padding: 24px 20px;
    gap: 20px;
    transform: translateY(-140%);
    opacity: 0;
    transition: transform var(--transition), opacity var(--transition);
  }

  .nav-links.open {
    transform: translateY(0);
    opacity: 1;
  }

  .hamburger { display: flex; }

  .gallery-nav-title {
    display: none; 
  }

  .hero-grid {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .hero-text { order: 2; }
  .hero-image-wrap { order: 1; }

  .hero-desc { margin-left: auto; margin-right: auto; }
  .hero-buttons, .social-icons { justify-content: center; }

  .about-cards { grid-template-columns: 1fr; }
  .skills-grid { grid-template-columns: repeat(2, 1fr); }
}