:root {
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: "SF Mono", Menlo, Consolas, Monaco, "Courier New", monospace;
  --transition: all 0.2s ease;
}

/* ==========================================
   THEME 1: DARK (Handmade Monochromatic Ink & Charcoal)
   ========================================== */
html[data-theme="dark"], html:not([data-theme]) {
  --bg: #09090b;
  --bg-subtle: #121215;
  --card-bg: rgba(18, 18, 22, 0.9);
  --card-border: #27272a;
  --card-hover-border: #52525b;
  --text-main: #fafafa;
  --text-muted: #a1a1aa;
  --text-dim: #71717a;
  --accent: #f4f4f5;
  --accent-glow: rgba(255, 255, 255, 0.08);
  --pill-bg: #18181b;
  --pill-border: #3f3f46;
  --badge-bg: rgba(255, 255, 255, 0.05);
}

/* ==========================================
   THEME 2: LIGHT (Handmade Clean Paper / Crisp Corporate White)
   ========================================== */
html[data-theme="light"] {
  --bg: #ffffff;
  --bg-subtle: #f4f4f5;
  --card-bg: #ffffff;
  --card-border: #e4e4e7;
  --card-hover-border: #a1a1aa;
  --text-main: #09090b;
  --text-muted: #3f3f46;
  --text-dim: #71717a;
  --accent: #09090b;
  --accent-glow: rgba(0, 0, 0, 0.06);
  --pill-bg: #f4f4f5;
  --pill-border: #d4d4d8;
  --badge-bg: #f4f4f5;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg);
  color: var(--text-main);
  line-height: 1.6;
  position: relative;
  min-height: 100vh;
  transition: background-color 0.25s ease, color 0.25s ease;
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: 860px;
  margin: 0 auto;
  padding: 0 1.5rem;
  position: relative;
  z-index: 1;
}

/* TOPBAR */
.topbar {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  background: var(--card-bg);
  border-bottom: 1px solid var(--card-border);
  padding: 0.85rem 0;
}

.topbar-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.topbar-left {
  display: flex;
  align-items: center;
}

.live-clock-tag {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.04em;
  color: var(--text-muted);
  background: var(--pill-bg);
  border: 1px solid var(--pill-border);
  padding: 0.3rem 0.7rem;
  border-radius: 9999px;
}

.live-dot {
  width: 6px;
  height: 6px;
  background-color: var(--accent);
  border-radius: 50%;
  animation: pulse 2.5s infinite ease-in-out;
}

@keyframes pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.4; transform: scale(0.85); }
}

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

.theme-switch-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--badge-bg);
  border: 1px solid var(--card-border);
  color: var(--text-main);
  padding: 0.35rem 0.75rem;
  border-radius: 9999px;
  font-family: var(--font-mono);
  font-size: 0.74rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
}

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

.theme-earth-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: var(--accent);
}

/* ANIMATIONS & TRANSITIONS */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(12px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.hero-section {
  padding: 3.5rem 0 2.25rem;
  animation: fadeInUp 0.6s cubic-bezier(0.16, 1, 0.3, 1) both;
}

.hero-name {
  font-size: 2.35rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  color: var(--text-main);
  margin-bottom: 0.45rem;
  line-height: 1.15;
}

.hero-role-title {
  font-family: var(--font-mono);
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-muted);
  margin-bottom: 1.25rem;
  letter-spacing: -0.01em;
}

.hero-lead {
  font-size: 1.08rem;
  color: var(--text-muted);
  line-height: 1.65;
  margin-bottom: 1.75rem;
  max-width: 44rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.85rem;
  margin-bottom: 1.5rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.92rem;
  font-weight: 600;
  padding: 0.7rem 1.35rem;
  border-radius: 8px;
  cursor: pointer;
  text-decoration: none;
  transition: var(--transition);
  font-family: var(--font-sans);
  border: 1px solid transparent;
}

.btn-primary {
  background: var(--accent);
  color: var(--bg);
}

html[data-theme="dark"] .btn-primary {
  background: #fafafa;
  color: #09090b;
}

html[data-theme="light"] .btn-primary {
  background: #09090b;
  color: #fafafa;
}

.btn-primary:hover {
  opacity: 0.92;
  transform: translateY(-1px);
}

.btn-secondary {
  background: var(--pill-bg);
  border-color: var(--pill-border);
  color: var(--text-main);
}

.btn-secondary:hover {
  border-color: var(--card-hover-border);
  transform: translateY(-1px);
}

.btn-sm {
  padding: 0.45rem 0.85rem;
  font-size: 0.82rem;
}

/* EMAIL REVEAL BOX */
.email-hero-box {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 8px;
  padding: 1rem 1.25rem;
  margin-bottom: 1.5rem;
  animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(-4px); }
  to { opacity: 1; transform: translateY(0); }
}

.email-display-row {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.email-address {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 0.95rem;
  color: var(--text-main);
}

.copy-status-msg {
  display: none;
  font-size: 0.8rem;
  color: var(--text-dim);
  font-family: var(--font-mono);
  margin-top: 0.5rem;
}

.hero-links-row {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  font-family: var(--font-mono);
  font-size: 0.84rem;
}

.hero-link {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  color: var(--text-muted);
  text-decoration: none;
  transition: var(--transition);
}

.hero-link:hover {
  color: var(--text-main);
}

.sep {
  color: var(--text-dim);
}

/* SECTIONS */
.section {
  padding: 2.25rem 0;
  border-top: 1px solid var(--card-border);
  animation: fadeInUp 0.5s cubic-bezier(0.16, 1, 0.3, 1) both;
}

.section-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: 1.25rem;
}

.section-title {
  font-size: 1.45rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.section-num {
  font-family: var(--font-mono);
  font-size: 0.76rem;
  letter-spacing: 0.08em;
  color: var(--text-dim);
}

/* SWITCH CONTROLLER */
.switch-controller {
  display: flex;
  gap: 0.5rem;
  background: var(--bg-subtle);
  border: 1px solid var(--card-border);
  padding: 0.3rem;
  border-radius: 10px;
  margin-bottom: 1.25rem;
}

.switch-tab {
  flex: 1;
  padding: 0.6rem 0.85rem;
  border-radius: 8px;
  background: transparent;
  border: none;
  color: var(--text-muted);
  font-size: 0.92rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
}

.switch-tab:hover {
  color: var(--text-main);
}

.switch-tab.active {
  background: var(--card-bg);
  color: var(--text-main);
  box-shadow: 0 2px 10px rgba(0,0,0,0.1);
  border: 1px solid var(--card-border);
}

.content-panel {
  display: none;
  opacity: 0;
  transform: translateY(14px);
}

.content-panel.active {
  display: block;
  animation: tabFadeSlide 0.65s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

@keyframes tabFadeSlide {
  0% {
    opacity: 0;
    transform: translateY(14px);
  }
  100% {
    opacity: 1;
    transform: translateY(0);
  }
}

#credentials-view .content-panel {
  min-height: 250px;
}

/* EXPERIENCE LIST */
.exp-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.exp-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 10px;
  padding: 1.35rem 1.5rem;
  transition: transform 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
}

.exp-card:hover {
  border-color: var(--card-hover-border);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.15);
}

.exp-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 0.75rem;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.exp-role {
  font-size: 1.12rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  margin-bottom: 0.15rem;
}

.exp-company {
  font-family: var(--font-mono);
  font-size: 0.86rem;
  color: var(--text-main);
  font-weight: 600;
}

.exp-meta {
  text-align: right;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-dim);
}

.exp-period {
  display: block;
  color: var(--text-muted);
  font-weight: 600;
}

.exp-bullets {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
}

.exp-bullets li {
  position: relative;
  padding-left: 1.15rem;
  font-size: 0.92rem;
  color: var(--text-muted);
  line-height: 1.5;
}

.exp-bullets li::before {
  content: "—";
  position: absolute;
  left: 0;
  color: var(--text-dim);
}

/* PROJECTS GRID */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
  gap: 1rem;
}

.proj-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 10px;
  padding: 1.35rem 1.45rem;
  transition: transform 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
  display: flex;
  flex-direction: column;
}

.proj-card:hover {
  border-color: var(--card-hover-border);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.15);
}

.proj-cat-badge {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--text-main);
  background: var(--pill-bg);
  border: 1px solid var(--pill-border);
  padding: 0.18rem 0.55rem;
  border-radius: 4px;
  margin-bottom: 0.65rem;
  align-self: flex-start;
}

.proj-title {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 0.4rem;
  letter-spacing: -0.01em;
  line-height: 1.35;
}

.proj-summary {
  font-size: 0.88rem;
  color: var(--text-muted);
  margin-bottom: 0.7rem;
  line-height: 1.45;
}

.proj-role-stack {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.76rem;
  margin-bottom: 0.75rem;
  padding-bottom: 0.65rem;
  border-bottom: 1px solid var(--card-border);
}

.proj-role {
  color: var(--text-main);
  font-weight: 600;
}

.proj-stack {
  color: var(--text-dim);
}

.proj-bullets {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  margin-top: auto;
}

.proj-bullets li {
  position: relative;
  padding-left: 1.15rem;
  font-size: 0.88rem;
  color: var(--text-muted);
  line-height: 1.45;
}

.proj-bullets li::before {
  content: "•";
  position: absolute;
  left: 0;
  color: var(--text-dim);
}

/* EDUCATION */
.edu-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 10px;
  padding: 1.5rem;
  height: 100%;
  box-sizing: border-box;
}

.edu-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 1rem;
  flex-wrap: wrap;
}

.edu-degree {
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: 0.2rem;
}

.edu-school {
  font-family: var(--font-mono);
  font-size: 0.9rem;
  color: var(--text-main);
  font-weight: 600;
}

.edu-meta {
  text-align: right;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-dim);
}

.edu-date {
  display: block;
  font-weight: 600;
  color: var(--text-muted);
}

.edu-honor {
  display: inline-flex;
  align-items: center;
  gap: 0.65rem;
  margin-bottom: 1rem;
}

.honor-badge {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--bg);
  background: var(--accent);
  padding: 0.2rem 0.6rem;
  border-radius: 4px;
}

.honor-sub {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-dim);
}

.edu-desc {
  font-size: 0.92rem;
  color: var(--text-muted);
  line-height: 1.55;
}

/* TECHNICAL COMPETENCIES */
.skills-layout {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.skill-category {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 10px;
  padding: 1.5rem;
}

.category-header h3 {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 0.25rem;
}

.category-header p {
  font-size: 0.88rem;
  color: var(--text-dim);
  margin-bottom: 1.25rem;
}

.skill-items-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1rem;
}

.skill-item {
  background: var(--bg-subtle);
  border: 1px solid var(--card-border);
  padding: 1rem;
  border-radius: 8px;
  transition: transform 0.2s ease, border-color 0.2s ease;
}

.skill-item:hover {
  border-color: var(--card-hover-border);
  transform: translateY(-2px);
}

.skill-name {
  font-weight: 700;
  font-size: 0.92rem;
  color: var(--text-main);
  margin-bottom: 0.35rem;
}

.skill-desc {
  font-size: 0.84rem;
  color: var(--text-muted);
  line-height: 1.45;
}

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

.skill-sub-list {
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
  margin-top: 0.85rem;
}

.skill-sub-item {
  font-size: 0.88rem;
  color: var(--text-muted);
  line-height: 1.5;
}

.skill-sub-item strong {
  color: var(--text-main);
}

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

.cert-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 10px;
  padding: 1.35rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: transform 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
}

.cert-card:hover {
  border-color: var(--card-hover-border);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.15);
}

.cert-issuer {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 0.35rem;
  font-weight: 600;
}

.cert-name {
  font-size: 0.98rem;
  font-weight: 700;
  line-height: 1.35;
  margin-bottom: 0.4rem;
}

.cert-validity {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-dim);
  margin-bottom: 1rem;
}

.cert-link {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-main);
  text-decoration: underline;
  font-weight: 600;
}

.cert-link:hover {
  color: var(--text-muted);
}

/* FOOTER */
.footer {
  border-top: 1px solid var(--card-border);
  padding: 1.75rem 0 2.25rem;
  margin-top: 2rem;
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
}

.footer-copy {
  font-size: 0.9rem;
  color: var(--text-muted);
  display: flex;
  align-items: center;
}

.footer-links {
  display: flex;
  align-items: center;
  gap: 1.25rem;
}

.footer-icon-link {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 500;
  line-height: 1;
  transition: var(--transition);
}

.footer-icon-link svg {
  display: block;
  flex-shrink: 0;
}

.footer-icon-link:hover {
  color: var(--text-main);
}

.footer-visits {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-dim);
  line-height: 1;
}

.visits-dot {
  width: 6px;
  height: 6px;
  background-color: var(--text-dim);
  border-radius: 50%;
}

/* BACK TO TOP BUTTON */
.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 42px;
  height: 42px;
  border-radius: 50%;
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  color: var(--text-main);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  z-index: 40;
  opacity: 0;
  pointer-events: none;
  transition: var(--transition);
  box-shadow: 0 4px 16px rgba(0,0,0,0.15);
}

.back-to-top.visible {
  opacity: 1;
  pointer-events: auto;
}

@media (max-width: 768px) {
  .hero-name { font-size: 1.95rem; }
  .section-head { flex-direction: column; gap: 0.25rem; }
  .skills-columns { grid-template-columns: 1fr; }
  .projects-grid { grid-template-columns: 1fr; }
  .footer-inner { flex-direction: column; align-items: flex-start; }
}