/* ============================================================
   1. CUSTOM PROPERTIES — GitHub Dimmed inspired
   ============================================================ */

html[data-theme="light"] {
  --bg-primary:    #f6f8fa;
  --bg-secondary:  #eaeef2;
  --bg-tertiary:   #d0d7de;
  --text-primary:  #1f2328;
  --text-secondary:#656d76;
  --accent:        #0969da;
  --accent-hover:  #0550ae;
  --accent-subtle: rgba(9, 105, 218, 0.1);
  --border:        #d0d7de;
  --border-muted:  #d8dee4;
  --card-bg:       #ffffff;
  --nav-bg:        rgba(246, 248, 250, 0.85);
  --tag-bg:        #ddf4ff;
  --tag-text:      #0969da;
  --tag-border:    #b6e3ff;
  --btn-primary-bg:#0969da;
  --btn-primary-fg:#ffffff;
  --btn-secondary-bg: transparent;
  --btn-secondary-fg: #1f2328;
  --btn-secondary-border: #d0d7de;
  --trusted-text:  #8b949e;
}

html[data-theme="dark"] {
  --bg-primary:    #22272e;
  --bg-secondary:  #2d333b;
  --bg-tertiary:   #373e47;
  --text-primary:  #adbac7;
  --text-secondary:#768390;
  --accent:        #539bf5;
  --accent-hover:  #6cb6ff;
  --accent-subtle: rgba(83, 155, 245, 0.1);
  --border:        #373e47;
  --border-muted:  #444c56;
  --card-bg:       #2d333b;
  --nav-bg:        rgba(34, 39, 46, 0.88);
  --tag-bg:        rgba(83, 155, 245, 0.1);
  --tag-text:      #539bf5;
  --tag-border:    rgba(83, 155, 245, 0.2);
  --btn-primary-bg:#539bf5;
  --btn-primary-fg:#22272e;
  --btn-secondary-bg: transparent;
  --btn-secondary-fg: #adbac7;
  --btn-secondary-border: #444c56;
  --trusted-text:  #545d68;
}

/* ============================================================
   2. RESET & BASE
   ============================================================ */

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  transition:
    background-color 0.3s ease,
    color 0.3s ease,
    border-color 0.3s ease;
}

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

body {
  background-color: var(--bg-primary);
  color: var(--text-primary);
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  font-weight: 400;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

img {
  display: block;
  max-width: 100%;
  height: auto;
  transition: none;
}

a {
  color: inherit;
  text-decoration: none;
}

ul {
  list-style: none;
}

button {
  cursor: pointer;
  background: none;
  border: none;
  font: inherit;
}

/* ============================================================
   3. LAYOUT UTILITIES
   ============================================================ */

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 2.5rem;
}

.text-accent {
  color: var(--accent);
}

.page-view[hidden] {
  display: none !important;
}

/* ============================================================
   4. TYPOGRAPHY
   ============================================================ */

.section-label {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 1rem;
}

.section-heading {
  font-size: clamp(1.8rem, 4vw, 2.5rem);
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.02em;
  color: var(--text-primary);
  margin-bottom: 2rem;
}

/* ============================================================
   5. NAVIGATION
   ============================================================ */

.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  padding: 1rem 0;
  transition: background-color 0.3s ease, backdrop-filter 0.3s ease, border-bottom 0.3s ease;
}

.nav.scrolled {
  background-color: var(--nav-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}

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

.nav-brand {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.nav-logo {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-primary);
  text-decoration: none;
  letter-spacing: -0.01em;
  line-height: 1.3;
}

.nav-subtitle {
  font-size: 0.72rem;
  font-weight: 500;
  color: var(--text-secondary);
  letter-spacing: 0.04em;
  line-height: 1.2;
}

.nav-right {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.nav-email {
  font-size: 0.8rem;
  font-weight: 400;
  color: var(--text-secondary);
  transition: color 0.2s ease;
}

.nav-email:hover {
  color: var(--accent);
}

.nav-links {
  display: flex;
  gap: 1.5rem;
  align-items: center;
}

.nav-link {
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-secondary);
  text-decoration: none;
  transition: color 0.2s ease;
  position: relative;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--accent);
  transition: width 0.25s ease;
  border-radius: 1px;
}

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

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

.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 6px;
  color: var(--text-secondary);
  transition: color 0.2s ease, background-color 0.2s ease;
  flex-shrink: 0;
}

.theme-toggle:hover {
  color: var(--text-primary);
  background-color: var(--bg-secondary);
}

html[data-theme="light"] .icon-sun { display: none; }
html[data-theme="light"] .icon-moon { display: block; }
html[data-theme="dark"] .icon-sun { display: block; }
html[data-theme="dark"] .icon-moon { display: none; }

/* Hamburger */
.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 4px;
}

.hamburger span {
  display: block;
  width: 22px;
  height: 1.5px;
  background-color: var(--text-primary);
  transition: transform 0.25s ease, opacity 0.25s ease;
}

.hamburger.open span:nth-child(1) { transform: translateY(6.5px) rotate(45deg); }
.hamburger.open span:nth-child(2) { opacity: 0; }
.hamburger.open span:nth-child(3) { transform: translateY(-6.5px) rotate(-45deg); }

/* ============================================================
   6. BUTTONS
   ============================================================ */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.65rem 1.5rem;
  font-size: 0.875rem;
  font-weight: 500;
  border-radius: 6px;
  letter-spacing: 0.01em;
  text-decoration: none;
  transition: transform 0.15s ease, background-color 0.2s ease, color 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
  white-space: nowrap;
}

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

.btn-primary {
  background-color: var(--btn-primary-bg);
  color: var(--btn-primary-fg);
  border: 1px solid var(--btn-primary-bg);
}

.btn-primary:hover {
  background-color: var(--accent-hover);
  border-color: var(--accent-hover);
  box-shadow: 0 4px 16px rgba(83, 155, 245, 0.2);
}

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

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

.btn-large {
  padding: 0.85rem 2rem;
  font-size: 0.95rem;
}

/* ============================================================
   7. HERO SECTION
   ============================================================ */

.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding: 7rem 0 3rem;
}

.hero-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 3rem;
  margin-bottom: 3rem;
}

.hero-text {
  flex: 1;
  min-width: 0;
}

.hero-portrait {
  flex-shrink: 0;
}

.hero-portrait img {
  width: 220px;
  height: 220px;
  border-radius: 50%;
  border: 3px solid var(--border);
  object-fit: cover;
  object-position: top;
}

.hero-eyebrow {
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
}

.hero-headline {
  font-size: clamp(2.2rem, 5vw, 3.5rem);
  font-weight: 700;
  line-height: 1.12;
  letter-spacing: -0.03em;
  color: var(--text-primary);
  margin-bottom: 1.5rem;
}

.hero-sub {
  font-size: 1.05rem;
  font-weight: 400;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 2rem;
  max-width: 520px;
}

.hero-actions {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

/* ============================================================
   8. TRUSTED BY
   ============================================================ */

.trusted-by {
  padding: 3rem 0;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.trusted-label {
  font-size: 0.72rem;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-secondary);
  text-align: center;
  margin-bottom: 1.5rem;
}

.trusted-logos {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 3rem;
  flex-wrap: wrap;
}

.trusted-logo-item {
  display: flex;
  align-items: center;
  justify-content: center;
}

.trusted-logo-text {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--trusted-text);
  letter-spacing: 0.04em;
  user-select: none;
  transition: color 0.2s ease;
}

.trusted-logo-item:hover .trusted-logo-text {
  color: var(--text-secondary);
}

/* ============================================================
   9. ABOUT SECTION
   ============================================================ */

.about {
  padding: 5rem 0;
}

.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: start;
}

.about-right p {
  font-size: 1rem;
  color: var(--text-secondary);
  line-height: 1.8;
  margin-bottom: 1rem;
}

.about-right p:last-of-type {
  margin-bottom: 0;
}

.about-stat {
  display: flex;
  align-items: baseline;
  gap: 0.6rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
}

.about-stat-number {
  font-size: 2rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.03em;
  line-height: 1;
}

.about-stat-label {
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.about-meta {
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
  padding-top: 1.2rem;
  border-top: 1px solid var(--border);
}

.meta-item {
  display: flex;
  gap: 1.5rem;
  align-items: baseline;
}

.meta-label {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-secondary);
  min-width: 90px;
  flex-shrink: 0;
}

.meta-value {
  font-size: 0.9rem;
  color: var(--text-primary);
}

/* ============================================================
   10. SERVICES SECTION
   ============================================================ */

.services {
  padding: 5rem 0;
  background-color: var(--bg-secondary);
}

.services-category {
  margin-bottom: 3rem;
}

.services-category:last-child {
  margin-bottom: 0;
}

.services-category-title {
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-secondary);
  margin-bottom: 1.2rem;
  padding-bottom: 0.8rem;
  border-bottom: 1px solid var(--border);
}

.services-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.2rem;
}

.service-card {
  padding: 1.8rem;
  background-color: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  transition: border-color 0.25s ease, box-shadow 0.25s ease;
}

.service-card:hover {
  border-color: var(--accent);
  box-shadow: 0 0 0 1px var(--accent-subtle);
}

.service-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  border-radius: 8px;
  background-color: var(--accent-subtle);
  color: var(--accent);
  margin-bottom: 1rem;
}

.service-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
  letter-spacing: -0.01em;
}

.service-desc {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.65;
  margin-bottom: 1rem;
}

.skill-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
}

.tag {
  display: inline-block;
  padding: 0.2rem 0.6rem;
  font-size: 0.75rem;
  font-weight: 500;
  background-color: var(--tag-bg);
  color: var(--tag-text);
  border-radius: 4px;
  border: 1px solid var(--tag-border);
  transition: background-color 0.2s ease, color 0.2s ease, border-color 0.2s ease;
}

.tag-sm {
  font-size: 0.72rem;
  padding: 0.18rem 0.5rem;
}

/* Consulting grid */
.consulting-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.2rem;
}

.consulting-item {
  padding: 1.5rem;
  background-color: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  transition: border-color 0.25s ease;
}

.consulting-item:hover {
  border-color: var(--accent);
}

.consulting-title {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.4rem;
}

.consulting-desc {
  font-size: 0.82rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* Certifications grid */
.cert-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.2rem;
}

.cert-card {
  display: flex;
  align-items: center;
  gap: 1.2rem;
  padding: 1.4rem 1.6rem;
  background-color: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  transition: border-color 0.25s ease, box-shadow 0.25s ease;
}

.cert-card:hover {
  border-color: var(--accent);
  box-shadow: 0 0 0 1px var(--accent-subtle);
}

.cert-badge {
  flex-shrink: 0;
  width: 72px;
  height: 72px;
  border-radius: 50%;
  transition: transform 0.25s ease;
}

.cert-card:hover .cert-badge {
  transform: scale(1.05);
}

.cert-info {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
  min-width: 0;
}

.cert-level {
  font-size: 0.68rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
}

.cert-title {
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--text-primary);
  line-height: 1.3;
  letter-spacing: -0.01em;
}

.cert-issuer {
  font-size: 0.78rem;
  color: var(--text-secondary);
  margin-top: 0.1rem;
}

/* ============================================================
   11. PROJECTS SECTION
   ============================================================ */

.projects {
  padding: 5rem 0;
}

.projects-list {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.project-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 2rem;
  padding: 1.5rem 0;
  border-bottom: 1px solid var(--border);
  transition: padding-left 0.2s ease;
}

.project-row:first-child {
  border-top: 1px solid var(--border);
}

.project-row:hover {
  padding-left: 0.5rem;
}

.project-info {
  flex: 1;
  min-width: 0;
}

.project-header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 0.3rem;
}

.project-name {
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--text-primary);
  letter-spacing: -0.01em;
}

.project-nda {
  display: inline-block;
  font-size: 0.65rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-muted);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 1px 6px;
  vertical-align: middle;
  margin-left: 0.5rem;
}

.project-link {
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-secondary);
  transition: color 0.2s ease, transform 0.2s ease;
}

.project-link:hover {
  color: var(--accent);
  transform: translate(2px, -2px);
}

.project-desc {
  font-size: 0.88rem;
  color: var(--text-secondary);
  line-height: 1.6;
  max-width: 560px;
}

.project-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  flex-shrink: 0;
}

/* ============================================================
   12. CONTACT SECTION
   ============================================================ */

.contact {
  padding: 5rem 0;
  background-color: var(--bg-secondary);
}

.contact-cta {
  max-width: 560px;
}

.contact .section-heading {
  margin-top: 0.5rem;
  margin-bottom: 1rem;
}

.contact-sub {
  font-size: 1rem;
  color: var(--text-secondary);
  line-height: 1.75;
  margin-bottom: 2rem;
}

.contact-actions {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

/* ============================================================
   13. CV DOWNLOAD BAND
   ============================================================ */

.cv-band {
  padding: 2.5rem 0;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.cv-band-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 2rem;
}

.cv-band-label {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-secondary);
  margin-bottom: 0.3rem;
}

.cv-band-desc {
  font-size: 0.9rem;
  color: var(--text-secondary);
}

/* ============================================================
   14. FOOTER
   ============================================================ */

.footer {
  padding: 2.5rem 0;
}

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

.footer-copy {
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.footer-links {
  display: flex;
  gap: 1.5rem;
}

.footer-link {
  font-size: 0.8rem;
  color: var(--text-secondary);
  text-decoration: none;
  transition: color 0.2s ease;
}

.footer-link:hover {
  color: var(--accent);
}

/* ============================================================
   15. SCROLL REVEAL ANIMATIONS
   ============================================================ */

@media (prefers-reduced-motion: no-preference) {
  .reveal {
    opacity: 0;
    transform: translateY(18px);
    transition: opacity 0.5s ease, transform 0.5s ease;
  }

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

  .service-card.reveal:nth-child(2) { transition-delay: 0.06s; }
  .service-card.reveal:nth-child(3) { transition-delay: 0.12s; }

  .consulting-item.reveal:nth-child(2) { transition-delay: 0.04s; }
  .consulting-item.reveal:nth-child(3) { transition-delay: 0.08s; }
  .consulting-item.reveal:nth-child(4) { transition-delay: 0.12s; }
  .consulting-item.reveal:nth-child(5) { transition-delay: 0.16s; }
  .consulting-item.reveal:nth-child(6) { transition-delay: 0.20s; }

  .project-row.reveal:nth-child(2) { transition-delay: 0.06s; }
  .project-row.reveal:nth-child(3) { transition-delay: 0.12s; }
}

@media (prefers-reduced-motion: reduce) {
  .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }
}

/* ============================================================
   16. RESPONSIVE — TABLET (max 900px)
   ============================================================ */

@media (max-width: 900px) {
  .about-grid {
    grid-template-columns: 1fr;
    gap: 2rem;
  }

  .services-grid {
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
  }

  .consulting-grid {
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
  }

  .cert-grid {
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
  }

  .project-row {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.75rem;
  }

  .hero-portrait img {
    width: 180px;
    height: 180px;
  }

  .nav-email {
    display: none;
  }
}

/* ============================================================
   17. RESPONSIVE — MOBILE (max 640px)
   ============================================================ */

@media (max-width: 640px) {
  .container {
    padding: 0 1.25rem;
  }

  .hamburger {
    display: flex;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background-color: var(--bg-primary);
    border-bottom: 1px solid var(--border);
    padding: 1.5rem 2rem;
    flex-direction: column;
    gap: 1.5rem;
    align-items: flex-start;
  }

  .nav-links.open {
    display: flex;
  }

  .nav-right {
    gap: 0.75rem;
  }

  .nav-email {
    display: none;
  }

  .hero {
    padding: 6rem 0 3rem;
    min-height: auto;
  }

  .hero-content {
    flex-direction: column-reverse;
    text-align: center;
    gap: 2rem;
  }

  .hero-text {
    display: flex;
    flex-direction: column;
    align-items: center;
  }

  .hero-sub {
    text-align: center;
  }

  .hero-headline {
    font-size: clamp(1.8rem, 8vw, 2.6rem);
  }

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

  .hero-portrait img {
    width: 160px;
    height: 160px;
  }

  .trusted-logos {
    gap: 1.5rem;
  }

  .trusted-logo-text {
    font-size: 1rem;
  }

  .about,
  .services,
  .projects,
  .contact {
    padding: 3.5rem 0;
  }

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

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

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

  .contact-actions {
    flex-direction: column;
    align-items: flex-start;
  }

  .cv-band-inner {
    flex-direction: column;
    align-items: flex-start;
    gap: 1.5rem;
  }

  .footer-inner {
    flex-direction: column;
    align-items: flex-start;
    gap: 1rem;
  }
}