/* ═══════════════════════════════════════════════════════════════
   SAGAR B. SURYAWANSHI — CYBERSECURITY PORTFOLIO
   style.css  |  Dark Navy + White + Electric Blue
   WCAG 2.1 AA compliant · Mobile-first responsive
═══════════════════════════════════════════════════════════════ */

/* ── CSS CUSTOM PROPERTIES ───────────────────────────────── */
:root {
  /* Colour Palette */
  --navy-950:   #020b18;
  --navy-900:   #061325;
  --navy-800:   #0a1f3d;
  --navy-700:   #0d2b55;
  --navy-600:   #103a72;
  --blue-500:   #1e6fff;
  --blue-400:   #3d84ff;
  --blue-300:   #6aa3ff;
  --blue-glow:  rgba(30, 111, 255, 0.25);
  --cyan-400:   #22d3ee;
  --white:      #ffffff;
  --grey-50:    #f8fafc;
  --grey-100:   #f1f5f9;
  --grey-200:   #e2e8f0;
  --grey-300:   #cbd5e1;
  --grey-400:   #94a3b8;
  --grey-500:   #64748b;
  --grey-600:   #475569;
  --green-400:  #4ade80;
  --green-500:  #22c55e;
  --gold-400:   #facc15;
  --red-400:    #f87171;

  /* Typography */
  --font-sans:  'Inter', system-ui, -apple-system, sans-serif;
  --font-mono:  'IBM Plex Mono', 'Fira Code', monospace;

  /* Spacing */
  --section-pad-y: 6rem;
  --section-max-w: 1200px;
  --nav-h:         68px;

  /* Effects */
  --radius-sm:   4px;
  --radius-md:   8px;
  --radius-lg:   16px;
  --radius-xl:   24px;
  --shadow-card: 0 4px 24px rgba(2, 11, 24, 0.6);
  --shadow-glow: 0 0 32px var(--blue-glow);
  --transition:  0.22s ease;
}

/* ── RESET & BASE ───────────────────────────────────────── */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  background-color: var(--navy-950);
  color: var(--grey-100);
  line-height: 1.7;
  overflow-x: hidden;
}

img {
  max-width: 100%;
  display: block;
}

a {
  color: var(--blue-400);
  text-decoration: none;
  transition: color var(--transition);
}

a:hover, a:focus-visible {
  color: var(--blue-300);
  outline: 2px solid var(--blue-400);
  outline-offset: 3px;
  border-radius: 2px;
}

ul { list-style: none; }

/* ── FOCUS VISIBLE (WCAG 2.1 AA) ────────────────────────── */
:focus-visible {
  outline: 2px solid var(--blue-400);
  outline-offset: 3px;
  border-radius: var(--radius-sm);
}

/* ── DEV BANNER ──────────────────────────────────────────── */
#dev-banner {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: linear-gradient(90deg, var(--navy-700), var(--blue-500));
  color: var(--white);
  font-size: 0.82rem;
  font-weight: 500;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  padding: 0.45rem 1rem;
  text-align: center;
}

#dev-banner.hidden {
  display: none;
}

#dismiss-banner {
  background: transparent;
  border: 1px solid rgba(255,255,255,0.4);
  color: var(--white);
  border-radius: var(--radius-sm);
  width: 22px;
  height: 22px;
  cursor: pointer;
  font-size: 0.75rem;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  transition: background var(--transition);
}

#dismiss-banner:hover {
  background: rgba(255,255,255,0.15);
}

/* ── NAVBAR ──────────────────────────────────────────────── */
#navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 900;
  height: var(--nav-h);
  display: flex;
  align-items: center;
  background: rgba(2, 11, 24, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(30, 111, 255, 0.12);
  transition: top var(--transition);
}

#navbar.banner-visible {
  top: 36px;
}

.nav-inner {
  max-width: var(--section-max-w);
  width: 100%;
  margin: 0 auto;
  padding: 0 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  font-family: var(--font-sans);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--white);
  letter-spacing: 0.02em;
}

.nav-logo:hover { color: var(--blue-300); }

.logo-bracket {
  color: var(--blue-400);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

.nav-links a {
  color: var(--grey-300);
  font-size: 0.88rem;
  font-weight: 500;
  padding: 0.4rem 0.7rem;
  border-radius: var(--radius-sm);
  transition: color var(--transition), background var(--transition);
}

.nav-links a:hover, .nav-links a.active {
  color: var(--blue-300);
  background: rgba(30, 111, 255, 0.08);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
}

.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--grey-200);
  border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition);
}

/* ── BUTTONS ────────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.7rem 1.5rem;
  border-radius: var(--radius-md);
  font-family: var(--font-sans);
  font-size: 0.92rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: all var(--transition);
  text-decoration: none;
  white-space: nowrap;
}

.btn-primary {
  background: var(--blue-500);
  color: var(--white);
  box-shadow: 0 4px 16px rgba(30, 111, 255, 0.35);
}

.btn-primary:hover {
  background: var(--blue-400);
  box-shadow: 0 4px 24px rgba(30, 111, 255, 0.5);
  color: var(--white);
  transform: translateY(-1px);
}

.btn-outline {
  background: transparent;
  color: var(--blue-300);
  border: 1.5px solid var(--blue-400);
}

.btn-outline:hover {
  background: rgba(30, 111, 255, 0.1);
  color: var(--blue-300);
  transform: translateY(-1px);
}

.btn-accent {
  background: linear-gradient(135deg, var(--blue-500), var(--cyan-400));
  color: var(--navy-950);
  font-weight: 700;
}

.btn-accent:hover {
  filter: brightness(1.1);
  color: var(--navy-950);
}

.btn-sm {
  padding: 0.45rem 1rem;
  font-size: 0.82rem;
}

/* ── SECTION COMMONS ─────────────────────────────────────── */
section {
  padding: var(--section-pad-y) 0;
}

.section-inner {
  max-width: var(--section-max-w);
  margin: 0 auto;
  padding: 0 2rem;
}

.section-label {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  font-weight: 500;
  color: var(--blue-400);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin-bottom: 0.6rem;
}

section h2 {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 800;
  color: var(--white);
  margin-bottom: 0.75rem;
  line-height: 1.2;
}

.section-subtext {
  color: var(--grey-400);
  font-size: 1rem;
  margin-bottom: 3rem;
  max-width: 640px;
}

/* Alternating section backgrounds */
section:nth-child(even) {
  background: var(--navy-900);
}

/* ── HERO SECTION ────────────────────────────────────────── */
#hero {
  min-height: 100vh;
  padding-top: calc(var(--nav-h) + 36px + 4rem);
  padding-bottom: 8rem;
  background: var(--navy-950);
  background-image:
    radial-gradient(ellipse 80% 60% at 70% 40%, rgba(30, 111, 255, 0.08) 0%, transparent 60%),
    radial-gradient(ellipse 40% 40% at 20% 80%, rgba(34, 211, 238, 0.04) 0%, transparent 50%);
  position: relative;
  overflow: hidden;
}

#hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(30, 111, 255, 0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(30, 111, 255, 0.03) 1px, transparent 1px);
  background-size: 48px 48px;
  pointer-events: none;
}

.hero-inner {
  max-width: var(--section-max-w);
  margin: 0 auto;
  padding: 0 2rem;
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 4rem;
  align-items: center;
  position: relative;
  z-index: 1;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: rgba(30, 111, 255, 0.1);
  border: 1px solid rgba(30, 111, 255, 0.3);
  border-radius: 100px;
  padding: 0.35rem 0.9rem;
  font-size: 0.8rem;
  color: var(--blue-300);
  font-weight: 500;
  margin-bottom: 1.5rem;
}

.badge-dot {
  width: 8px;
  height: 8px;
  background: var(--green-400);
  border-radius: 50%;
  animation: pulse-dot 2s infinite;
  flex-shrink: 0;
}

@keyframes pulse-dot {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.6; transform: scale(0.85); }
}

#hero h1 {
  font-size: clamp(2.8rem, 7vw, 5rem);
  font-weight: 800;
  line-height: 1.05;
  color: var(--white);
  margin-bottom: 0.75rem;
}

.hero-name-accent {
  color: var(--white);
}

.hero-title {
  font-size: clamp(1.1rem, 2.5vw, 1.35rem);
  font-weight: 700;
  color: var(--grey-100);
  margin-bottom: 0.25rem;
}

.hero-focus {
  font-size: clamp(0.85rem, 1.8vw, 1rem);
  font-weight: 500;
  color: var(--cyan-400);
  margin-bottom: 0.6rem;
  letter-spacing: 0.02em;
}

.hero-subtitle {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--grey-500);
  margin-bottom: 1.5rem;
  letter-spacing: 0.04em;
}

/* Cert links in hero strip — inherit look, subtle dotted underline */
.cert-link {
  color: inherit;
  text-decoration: none;
  border-bottom: 1px dotted currentColor;
  opacity: 0.85;
  transition: opacity 0.15s ease;
}
.cert-link:hover,
.cert-link:focus-visible {
  opacity: 1;
  border-bottom: 1px solid currentColor;
  outline: none;
}

.hero-tagline {
  font-size: 1rem;
  color: var(--grey-400);
  max-width: 560px;
  margin-bottom: 2rem;
  line-height: 1.75;
}

.hero-cta {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  margin-bottom: 3rem;
}

.hero-trust {
  display: flex;
  gap: 0;
  align-items: center;
  flex-wrap: wrap;
  gap: 0;
}

.trust-item {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  padding: 0 1.5rem 0 0;
}

.trust-item:first-child { padding-left: 0; }

.trust-number {
  font-size: 1.7rem;
  font-weight: 800;
  color: var(--blue-300);
  line-height: 1;
  font-family: var(--font-mono);
}

.trust-label {
  font-size: 0.75rem;
  color: var(--grey-500);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.trust-divider {
  width: 1px;
  height: 36px;
  background: rgba(30, 111, 255, 0.2);
  margin: 0 1rem;
}

/* Hero Photo */
.hero-photo-wrapper {
  position: relative;
  flex-shrink: 0;
}

.hero-photo-ring {
  width: 300px;
  height: 300px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--blue-500), var(--cyan-400));
  padding: 4px;
  box-shadow: var(--shadow-glow);
  position: relative;
}

.hero-photo {
  width: 100%;
  height: 100%;
  border-radius: 50%;
  object-fit: cover;
  object-position: top center;
  background: var(--navy-800);
  user-select: none;
  -webkit-user-drag: none;
}

.hero-photo-badge {
  position: absolute;
  bottom: 12px;
  right: -8px;
  background: var(--navy-800);
  border: 1.5px solid var(--blue-500);
  border-radius: 100px;
  padding: 0.35rem 0.75rem;
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--blue-300);
  display: flex;
  align-items: center;
  gap: 0.35rem;
  box-shadow: var(--shadow-card);
}

.hero-scroll-hint {
  position: absolute;
  bottom: 2.5rem;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  color: var(--grey-600);
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-family: var(--font-mono);
}

.scroll-line {
  width: 1px;
  height: 36px;
  background: linear-gradient(to bottom, var(--grey-600), transparent);
  animation: scroll-line 2s ease-in-out infinite;
}

@keyframes scroll-line {
  0%, 100% { opacity: 1; transform: scaleY(1); }
  50% { opacity: 0.4; transform: scaleY(0.7); }
}

/* ── ABOUT SECTION ───────────────────────────────────────── */
#about {
  background: var(--navy-900);
}

.about-grid {
  display: grid;
  grid-template-columns: 1fr 320px;
  gap: 4rem;
  align-items: start;
}

.about-text p {
  color: var(--grey-300);
  margin-bottom: 1.25rem;
  font-size: 1rem;
  line-height: 1.8;
  font-weight: 400;
}

.about-text strong {
  color: var(--white);
}

.about-highlights {
  margin-top: 2rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.highlight-item {
  display: flex;
  align-items: flex-start;
  gap: 0.85rem;
  background: rgba(30, 111, 255, 0.06);
  border: 1px solid rgba(30, 111, 255, 0.12);
  border-radius: var(--radius-md);
  padding: 0.9rem 1.1rem;
}

.highlight-icon {
  font-size: 1.2rem;
  flex-shrink: 0;
  margin-top: 0.1rem;
}

.highlight-item strong {
  display: block;
  color: var(--white);
  font-size: 0.9rem;
  margin-bottom: 0.1rem;
}

.highlight-item span {
  color: var(--grey-400);
  font-size: 0.83rem;
}

.about-stats {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.stat-card {
  background: var(--navy-800);
  border: 1px solid rgba(30, 111, 255, 0.15);
  border-radius: var(--radius-lg);
  padding: 1.25rem 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
  transition: border-color var(--transition), box-shadow var(--transition);
}

.stat-card:hover {
  border-color: var(--blue-500);
  box-shadow: 0 4px 20px var(--blue-glow);
}

.stat-icon {
  font-size: 1.5rem;
  margin-bottom: 0.3rem;
}

.stat-card strong {
  color: var(--white);
  font-size: 0.95rem;
}

.stat-card span {
  color: var(--grey-400);
  font-size: 0.82rem;
  font-family: var(--font-mono);
}

/* ── SKILLS — TABS ───────────────────────────────────────── */
#skills {
  background: var(--navy-950);
}

.skills-tabs {
  margin-bottom: 2.5rem;
}

.tab-nav {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
  margin-bottom: 2rem;
  border-bottom: 1px solid rgba(30, 111, 255, 0.15);
  padding-bottom: 0;
}

.tab-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.65rem 1.2rem;
  background: transparent;
  border: none;
  border-bottom: 2px solid transparent;
  color: var(--grey-400);
  font-family: var(--font-sans);
  font-size: 0.88rem;
  font-weight: 600;
  cursor: pointer;
  transition: color var(--transition), border-color var(--transition), background var(--transition);
  border-radius: var(--radius-sm) var(--radius-sm) 0 0;
  white-space: nowrap;
  margin-bottom: -1px;
}

.tab-btn:hover {
  color: var(--blue-300);
  background: rgba(30, 111, 255, 0.06);
}

.tab-btn.active {
  color: var(--blue-300);
  border-bottom-color: var(--blue-400);
  background: rgba(30, 111, 255, 0.08);
}

.tab-icon {
  font-size: 1rem;
}

.tab-panel {
  display: none;
  animation: fadePanel 0.25s ease;
}

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

@keyframes fadePanel {
  from { opacity: 0; transform: translateY(6px); }
  to   { opacity: 1; transform: translateY(0); }
}

.skills-pills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 1.75rem;
}

.skills-pills-col {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.pills-group-label {
  font-size: 0.72rem;
  font-weight: 700;
  color: var(--blue-400);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-family: var(--font-mono);
}

.skill-pills {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
}

.skill-pill {
  background: rgba(30, 111, 255, 0.08);
  border: 1px solid rgba(30, 111, 255, 0.18);
  color: var(--grey-200);
  font-size: 0.8rem;
  font-weight: 500;
  padding: 0.3rem 0.7rem;
  border-radius: 6px;
  cursor: default;
  transition: background var(--transition), border-color var(--transition), color var(--transition);
}

.skill-pill:hover {
  background: rgba(30, 111, 255, 0.18);
  border-color: var(--blue-400);
  color: var(--white);
}

/* Keep old .skills-grid / .skill-group / .skill-bar hidden if present */
.skills-grid, .skill-bar, .skill-fill { display: none; }

.tech-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.tag {
  background: rgba(30, 111, 255, 0.1);
  border: 1px solid rgba(30, 111, 255, 0.2);
  color: var(--blue-300);
  font-size: 0.78rem;
  font-weight: 500;
  padding: 0.25rem 0.7rem;
  border-radius: 100px;
  font-family: var(--font-mono);
}

.tag-green {
  background: rgba(74, 222, 128, 0.1);
  border-color: rgba(74, 222, 128, 0.25);
  color: var(--green-400);
}

.tag-gold {
  background: rgba(250, 204, 21, 0.1);
  border-color: rgba(250, 204, 21, 0.25);
  color: var(--gold-400);
}

/* ── CERTIFICATIONS ──────────────────────────────────────── */
#certifications {
  background: var(--navy-900);
}

.certs-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.5rem;
}

.cert-card {
  background: var(--navy-800);
  border: 1px solid rgba(30, 111, 255, 0.15);
  border-radius: var(--radius-xl);
  padding: 2rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  transition: border-color var(--transition), box-shadow var(--transition), transform var(--transition);
}

.cert-card:hover {
  border-color: var(--blue-500);
  box-shadow: 0 8px 32px var(--blue-glow);
  transform: translateY(-3px);
}

.cert-featured {
  border-color: rgba(30, 111, 255, 0.4);
  background: linear-gradient(135deg, var(--navy-800), rgba(30, 111, 255, 0.06));
  box-shadow: 0 4px 24px var(--blue-glow);
}

.cert-verified {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.76rem;
  font-weight: 600;
  color: var(--green-400);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.verified-dot {
  width: 7px;
  height: 7px;
  background: var(--green-400);
  border-radius: 50%;
  display: inline-block;
}

.cert-logo-svg {
  height: 38px;
  width: auto;
  max-width: 140px;
  display: block;
}

.cert-logo-img {
  height: 48px;
  width: auto;
  max-width: 160px;
  display: block;
  object-fit: contain;
}

.cert-logo {
  margin-bottom: 0.25rem;
}

.cert-verify-link {
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  font-size: 0.83rem;
  font-weight: 600;
  color: var(--blue-400);
  margin-top: auto;
  padding-top: 0.5rem;
  border-top: 1px solid rgba(30, 111, 255, 0.1);
  width: 100%;
  transition: color var(--transition), gap var(--transition);
}

.cert-verify-link:hover {
  color: var(--blue-300);
  gap: 0.45rem;
}

.cert-name {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--white);
}

.cert-code {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--blue-300);
}

.cert-desc {
  font-size: 0.88rem;
  color: var(--grey-400);
  line-height: 1.7;
  flex: 1;
}

.cert-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

/* ── PROJECTS SECTION ────────────────────────────────────── */
#projects {
  background: var(--navy-950);
}

.projects-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.5rem;
}

.project-card {
  background: var(--navy-800);
  border: 1px solid rgba(30, 111, 255, 0.12);
  border-radius: var(--radius-xl);
  padding: 2rem;
  display: flex;
  gap: 1.25rem;
  transition: border-color var(--transition), box-shadow var(--transition), transform var(--transition);
  position: relative;
  overflow: hidden;
}

.project-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--blue-500), var(--cyan-400));
  opacity: 0;
  transition: opacity var(--transition);
}

.project-card:hover {
  border-color: var(--blue-500);
  box-shadow: 0 8px 32px var(--blue-glow);
  transform: translateY(-3px);
}

.project-card:hover::before {
  opacity: 1;
}

.project-featured {
  border-color: rgba(30, 111, 255, 0.3);
}

.project-featured:hover {
  border-color: var(--blue-500);
  box-shadow: 0 8px 32px var(--blue-glow);
  transform: translateY(-3px);
}

.project-featured:hover::before {
  opacity: 1;
}

.project-wide {
  grid-column: span 2;
}

.project-number {
  font-family: var(--font-mono);
  font-size: 2rem;
  font-weight: 700;
  color: rgba(30, 111, 255, 0.2);
  line-height: 1;
  flex-shrink: 0;
  align-self: flex-start;
  margin-top: 0.15rem;
}

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

.project-research-badge {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--blue-400);
  background: rgba(30, 111, 255, 0.1);
  border: 1px solid rgba(30, 111, 255, 0.25);
  border-radius: 4px;
  padding: 0.2rem 0.55rem;
  margin-bottom: 0.5rem;
}

.project-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--white);
  margin-bottom: 0.6rem;
}

.project-impact {
  font-size: 0.9rem;
  color: var(--grey-300);
  line-height: 1.7;
  margin-bottom: 0.6rem;
  font-weight: 500;
}

.project-desc {
  font-size: 0.85rem;
  color: var(--grey-400);
  line-height: 1.75;
  margin-bottom: 1rem;
}

.project-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-bottom: 1rem;
}

.project-link {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--blue-400);
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  transition: gap var(--transition), color var(--transition);
}

.project-link:hover {
  color: var(--blue-300);
  gap: 0.5rem;
}

/* ── EXPERIENCE / TIMELINE ───────────────────────────────── */
#experience {
  background: var(--navy-900);
}

.timeline {
  display: flex;
  flex-direction: column;
  gap: 0;
  position: relative;
  padding-left: 2.5rem;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 8px;
  top: 12px;
  bottom: 12px;
  width: 2px;
  background: linear-gradient(to bottom, var(--blue-500), rgba(30, 111, 255, 0.1));
}

.timeline-item {
  position: relative;
  padding-bottom: 2.5rem;
}

.timeline-item:last-child {
  padding-bottom: 0;
}

.timeline-dot {
  position: absolute;
  left: -2.5rem;
  top: 12px;
  width: 18px;
  height: 18px;
  background: var(--navy-900);
  border: 3px solid var(--blue-500);
  border-radius: 50%;
  box-shadow: 0 0 12px var(--blue-glow);
}

.timeline-card {
  background: var(--navy-800);
  border: 1px solid rgba(30, 111, 255, 0.15);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  transition: border-color var(--transition);
}

.timeline-card:hover {
  border-color: rgba(30, 111, 255, 0.35);
}

.timeline-header {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
  margin-bottom: 1rem;
}

.timeline-org {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.org-name {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--white);
}

.org-badge {
  background: rgba(30, 111, 255, 0.12);
  border: 1px solid rgba(30, 111, 255, 0.25);
  color: var(--blue-300);
  font-size: 0.72rem;
  font-weight: 600;
  padding: 0.15rem 0.6rem;
  border-radius: 100px;
  font-family: var(--font-mono);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.timeline-role {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--grey-400);
}

.timeline-duties {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  margin-bottom: 1rem;
}

.timeline-duties li {
  font-size: 0.9rem;
  color: var(--grey-300);
  padding-left: 1rem;
  position: relative;
  line-height: 1.65;
}

.timeline-duties li::before {
  content: '›';
  position: absolute;
  left: 0;
  color: var(--blue-400);
  font-weight: 700;
}

.timeline-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

/* ── RESEARCH SECTION ────────────────────────────────────── */
#research {
  background: var(--navy-950);
}

.research-card {
  background: var(--navy-800);
  border: 1px solid rgba(250, 204, 21, 0.2);
  border-radius: var(--radius-xl);
  padding: 2.5rem;
  margin-bottom: 2.5rem;
  position: relative;
  overflow: hidden;
}

.research-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--gold-400), #f97316);
}

.research-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: rgba(250, 204, 21, 0.1);
  border: 1px solid rgba(250, 204, 21, 0.25);
  color: var(--gold-400);
  font-size: 0.78rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  padding: 0.3rem 0.8rem;
  border-radius: 100px;
  margin-bottom: 1.25rem;
}

.research-title {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--white);
  margin-bottom: 0.75rem;
  line-height: 1.35;
}

.research-meta {
  font-size: 0.88rem;
  color: var(--grey-400);
  line-height: 1.8;
  margin-bottom: 1rem;
  font-family: var(--font-mono);
}

.research-meta strong {
  color: var(--grey-200);
}

.research-abstract {
  font-size: 0.95rem;
  color: var(--grey-300);
  line-height: 1.8;
  margin-bottom: 1.5rem;
}

.research-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.achievements-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.25rem;
}

.achievement-item {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  background: var(--navy-800);
  border: 1px solid rgba(30, 111, 255, 0.12);
  border-radius: var(--radius-lg);
  padding: 1.25rem 1.5rem;
  transition: border-color var(--transition);
}

.achievement-item:hover {
  border-color: rgba(30, 111, 255, 0.3);
}

.achievement-icon {
  font-size: 1.5rem;
  flex-shrink: 0;
}

.achievement-item strong {
  display: block;
  color: var(--white);
  font-size: 0.92rem;
  margin-bottom: 0.25rem;
}

.achievement-item span {
  color: var(--grey-400);
  font-size: 0.83rem;
  line-height: 1.6;
}

/* ── CONTACT SECTION ─────────────────────────────────────── */
#contact {
  background: var(--navy-900);
}

.contact-intro {
  text-align: center;
  margin: 0 auto 3rem;
  max-width: 520px;
}

section#contact h2 {
  text-align: center;
}

section#contact .section-label {
  text-align: center;
}

.contact-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.25rem;
  margin-bottom: 2rem;
}

.contact-card {
  background: var(--navy-800);
  border: 1px solid rgba(30, 111, 255, 0.15);
  border-radius: var(--radius-lg);
  padding: 1.75rem 1.25rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  text-align: center;
  text-decoration: none;
  transition: border-color var(--transition), box-shadow var(--transition), transform var(--transition);
}

.contact-card:hover {
  border-color: var(--blue-500);
  box-shadow: 0 6px 24px var(--blue-glow);
  transform: translateY(-3px);
  color: inherit;
}

.contact-icon {
  font-size: 1.75rem;
}

.contact-label {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--grey-500);
}

.contact-value {
  font-size: 0.82rem;
  color: var(--blue-300);
  word-break: break-all;
  font-family: var(--font-mono);
}

.contact-cv {
  cursor: default;
}

.contact-cv:hover {
  border-color: var(--blue-500);
}

.gdpr-note {
  text-align: center;
  font-size: 0.8rem;
  color: var(--grey-600);
  border-top: 1px solid rgba(30, 111, 255, 0.08);
  padding-top: 1.5rem;
}

.gdpr-note strong {
  color: var(--grey-400);
}

/* ── FOOTER ──────────────────────────────────────────────── */
footer {
  background: var(--navy-950);
  border-top: 1px solid rgba(30, 111, 255, 0.1);
  padding: 2.5rem 2rem;
}

.footer-inner {
  max-width: var(--section-max-w);
  margin: 0 auto;
  text-align: center;
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.footer-logo {
  font-family: var(--font-sans);
  font-size: 1rem;
  font-weight: 700;
  color: var(--white);
  letter-spacing: 0.01em;
}

.footer-tagline {
  font-size: 0.88rem;
  color: var(--grey-500);
}

.footer-legal {
  font-size: 0.78rem;
  color: var(--grey-600);
  font-family: var(--font-mono);
}

/* ── SCROLL REVEAL ANIMATIONS ────────────────────────────── */
.reveal {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

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

/* ── RESPONSIVE — TABLET ─────────────────────────────────── */
@media (max-width: 1024px) {
  .about-grid {
    grid-template-columns: 1fr;
  }

  .about-stats {
    flex-direction: row;
    flex-wrap: wrap;
  }

  .stat-card {
    flex: 1 1 140px;
  }

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

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

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

  .hero-photo-ring {
    width: 240px;
    height: 240px;
  }
}

/* ── RESPONSIVE — MOBILE ─────────────────────────────────── */
@media (max-width: 768px) {
  :root {
    --section-pad-y: 4rem;
  }

  .nav-links {
    display: none;
    position: fixed;
    inset: var(--nav-h) 0 0 0;
    background: rgba(2, 11, 24, 0.98);
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 1rem;
    padding: 2rem;
    z-index: 850;
  }

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

  .nav-links a {
    font-size: 1.1rem;
    padding: 0.7rem 1.5rem;
  }

  .nav-toggle {
    display: flex;
  }

  .hero-inner {
    grid-template-columns: 1fr;
    gap: 2.5rem;
    text-align: center;
  }

  .hero-photo-wrapper {
    order: -1;
    display: flex;
    justify-content: center;
    position: relative;
  }

  .hero-photo-ring {
    width: 200px;
    height: 200px;
  }

  .hero-badge {
    margin: 0 auto 1.5rem;
  }

  .hero-cta {
    justify-content: center;
  }

  .hero-trust {
    justify-content: center;
  }

  .skills-pills-grid {
    grid-template-columns: 1fr;
  }

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

  .tab-nav {
    gap: 0.3rem;
  }

  .tab-btn {
    font-size: 0.8rem;
    padding: 0.5rem 0.8rem;
  }

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

  .project-wide {
    grid-column: span 1;
  }

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

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

  .timeline {
    padding-left: 2rem;
  }
}

@media (max-width: 480px) {
  .contact-grid {
    grid-template-columns: 1fr;
  }

  .trust-divider {
    display: none;
  }

  .hero-trust {
    gap: 1rem;
  }

  .trust-item {
    padding: 0;
    align-items: center;
  }
}

/* ── RESEARCH LINKS ──────────────────────────────────────── */
.research-links {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-top: 1rem;
  align-items: center;
}

.research-cert-btn {
  background: none;
  border: none;
  padding: 0;
  cursor: pointer;
  font-family: inherit;
  font-size: inherit;
}

/* ── PRINT ───────────────────────────────────────────────── */
@media print {
  #dev-banner, #navbar, .hero-scroll-hint { display: none; }
  body { background: white; color: black; }
  section { page-break-inside: avoid; }
}

/* ═══════════════════════════════════════════════════════════
   THEME TOGGLE BUTTON
═══════════════════════════════════════════════════════════ */
#theme-toggle {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: transparent;
  border: 1.5px solid rgba(30, 111, 255, 0.3);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  padding: 0;
  flex-shrink: 0;
  transition: background var(--transition), border-color var(--transition), transform var(--transition);
}

#theme-toggle:hover {
  background: rgba(30, 111, 255, 0.12);
  border-color: var(--blue-400);
  transform: rotate(15deg) scale(1.08);
}

.theme-icon {
  position: absolute;
  font-size: 1rem;
  line-height: 1;
  pointer-events: none;
  transition: opacity 0.22s ease, transform 0.22s ease;
}

/* Dark mode (default): show moon, hide sun */
.theme-icon-moon { opacity: 1; transform: scale(1) rotate(0deg); }
.theme-icon-sun  { opacity: 0; transform: scale(0.5) rotate(90deg); }

/* Light mode: show sun, hide moon */
html.light .theme-icon-moon { opacity: 0; transform: scale(0.5) rotate(-90deg); }
html.light .theme-icon-sun  { opacity: 1; transform: scale(1) rotate(0deg); }

html.light #theme-toggle {
  border-color: rgba(15, 23, 42, 0.2);
}
html.light #theme-toggle:hover {
  background: rgba(15, 23, 42, 0.07);
  border-color: rgba(15, 23, 42, 0.35);
  transform: rotate(15deg) scale(1.08);
}

/* ── THEME TRANSITION (only active during toggle click) ── */
html.theme-transitioning *,
html.theme-transitioning *::before,
html.theme-transitioning *::after {
  transition:
    background-color 0.28s ease,
    color 0.22s ease,
    border-color 0.28s ease,
    box-shadow 0.28s ease !important;
}

/* ═══════════════════════════════════════════════════════════
   LIGHT MODE — html.light overrides
   Default is light; dark requires html.dark (set by theme-init.js)
═══════════════════════════════════════════════════════════ */

html.light body {
  background-color: #f1f5f9;
  color: #0f172a;
}

html.light a {
  color: #1d4ed8;
}
html.light a:hover, html.light a:focus-visible {
  color: #1e40af;
  outline-color: #1d4ed8;
}

/* ── Navbar ── */
html.light #navbar {
  background: rgba(255, 255, 255, 0.97);
  border-bottom: 1px solid rgba(15, 23, 42, 0.08);
}
html.light .nav-logo { color: #0f172a; }
html.light .nav-logo:hover { color: #1d4ed8; }
html.light .nav-links a { color: #475569; }
html.light .nav-links a:hover,
html.light .nav-links a.active {
  color: #1d4ed8;
  background: rgba(29, 78, 216, 0.06);
}
html.light .nav-toggle span { background: #1e293b; }

/* ── Section common ── */
html.light section h2 { color: #0f172a; }
html.light .section-subtext { color: #64748b; }
html.light section:nth-child(even) { background: #e2eaf5; }
html.light .section-label { color: #1d4ed8; }

/* ── Hero ── */
html.light #hero {
  background: #f1f5f9;
  background-image:
    radial-gradient(ellipse 80% 60% at 70% 40%, rgba(29, 78, 216, 0.07) 0%, transparent 60%),
    radial-gradient(ellipse 40% 40% at 20% 80%, rgba(34, 211, 238, 0.05) 0%, transparent 50%);
}
html.light #hero::before {
  background-image:
    linear-gradient(rgba(29, 78, 216, 0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(29, 78, 216, 0.04) 1px, transparent 1px);
}
html.light #hero h1 { color: #0f172a; }
html.light .hero-name-accent { color: #0f172a; }
html.light .hero-title { color: #0f172a; }
html.light .hero-tagline { color: #475569; }
html.light .hero-subtitle { color: #6b7280; }
html.light .cert-link { color: inherit; }
html.light .trust-label { color: #94a3b8; }
html.light .trust-divider { background: rgba(29, 78, 216, 0.15); }
html.light .hero-photo { background: #e2e8f0; }
html.light .hero-photo-badge {
  background: #ffffff;
  border-color: #1d4ed8;
  color: #1d4ed8;
}
html.light .hero-scroll-hint { color: #94a3b8; }

/* ── About ── */
html.light #about { background: #e2eaf5; }
html.light .about-text p { color: #1e293b; }
html.light .about-text strong { color: #0f172a; }
html.light .highlight-item {
  background: rgba(29, 78, 216, 0.04);
  border-color: rgba(29, 78, 216, 0.1);
}
html.light .highlight-item strong { color: #0f172a; }
html.light .highlight-item span { color: #64748b; }
html.light .stat-card {
  background: #ffffff;
  border-color: rgba(15, 23, 42, 0.1);
  box-shadow: 0 2px 12px rgba(15, 23, 42, 0.06);
}
html.light .stat-card strong { color: #0f172a; }
html.light .stat-card span { color: #64748b; }

/* ── Skills ── */
html.light #skills { background: #f1f5f9; }
html.light .tab-nav { border-bottom-color: rgba(15, 23, 42, 0.12); }
html.light .tab-btn { color: #64748b; }
html.light .tab-btn:hover {
  color: #1d4ed8;
  background: rgba(29, 78, 216, 0.05);
}
html.light .tab-btn.active {
  color: #1d4ed8;
  border-bottom-color: #1d4ed8;
  background: rgba(29, 78, 216, 0.07);
}
html.light .skill-pill {
  background: rgba(15, 23, 42, 0.05);
  border-color: rgba(15, 23, 42, 0.12);
  color: #1e293b;
}
html.light .skill-pill:hover {
  background: rgba(29, 78, 216, 0.08);
  border-color: #1d4ed8;
  color: #0f172a;
}
html.light .pills-group-label { color: #1d4ed8; }
html.light .tag {
  background: rgba(29, 78, 216, 0.07);
  border-color: rgba(29, 78, 216, 0.2);
  color: #1d4ed8;
}

/* ── Certifications ── */
html.light #certifications { background: #e2eaf5; }
html.light .cert-card {
  background: #ffffff;
  border-color: rgba(15, 23, 42, 0.1);
  box-shadow: 0 2px 16px rgba(15, 23, 42, 0.06);
}
html.light .cert-featured {
  border-color: rgba(29, 78, 216, 0.3);
  background: linear-gradient(135deg, #ffffff, rgba(29, 78, 216, 0.03));
  box-shadow: 0 4px 24px rgba(29, 78, 216, 0.1);
}
html.light .cert-name { color: #0f172a; }
html.light .cert-desc { color: #475569; }
html.light .cert-verify-link { border-top-color: rgba(15, 23, 42, 0.08); }

/* ── Projects ── */
html.light #projects { background: #f1f5f9; }
html.light .project-card {
  background: #ffffff;
  border-color: rgba(15, 23, 42, 0.1);
  box-shadow: 0 2px 16px rgba(15, 23, 42, 0.06);
}
html.light .project-title { color: #0f172a; }
html.light .project-impact { color: #334155; }
html.light .project-desc { color: #475569; }
html.light .project-number { color: rgba(29, 78, 216, 0.12); }

/* ── Experience / Timeline ── */
html.light #experience { background: #e2eaf5; }
html.light .timeline-dot { background: #e2eaf5; }
html.light .timeline-card {
  background: #ffffff;
  border-color: rgba(15, 23, 42, 0.1);
  box-shadow: 0 2px 16px rgba(15, 23, 42, 0.06);
}
html.light .org-name { color: #0f172a; }
html.light .org-badge {
  background: rgba(29, 78, 216, 0.07);
  border-color: rgba(29, 78, 216, 0.15);
}
html.light .timeline-role { color: #64748b; }
html.light .timeline-duties li { color: #334155; }

/* ── Research ── */
html.light #research { background: #f1f5f9; }
html.light .research-card {
  background: #ffffff;
  border-color: rgba(202, 138, 4, 0.2);
  box-shadow: 0 2px 16px rgba(15, 23, 42, 0.06);
}
html.light .research-title { color: #0f172a; }
html.light .research-meta { color: #64748b; }
html.light .research-meta strong { color: #334155; }
html.light .research-abstract { color: #334155; }
html.light .achievement-item {
  background: #ffffff;
  border-color: rgba(15, 23, 42, 0.1);
  box-shadow: 0 2px 8px rgba(15, 23, 42, 0.05);
}
html.light .achievement-item strong { color: #0f172a; }
html.light .achievement-item span { color: #64748b; }

/* ── Contact ── */
html.light #contact { background: #e2eaf5; }
html.light .contact-card {
  background: #ffffff;
  border-color: rgba(15, 23, 42, 0.1);
  box-shadow: 0 2px 12px rgba(15, 23, 42, 0.05);
}
html.light .contact-label { color: #94a3b8; }
html.light .gdpr-note {
  color: #94a3b8;
  border-top-color: rgba(15, 23, 42, 0.08);
}
html.light .gdpr-note strong { color: #64748b; }

/* ── Footer ── */
html.light footer {
  background: #f1f5f9;
  border-top-color: rgba(15, 23, 42, 0.08);
}
html.light .footer-logo { color: #0f172a; }
html.light .footer-tagline { color: #64748b; }
html.light .footer-legal { color: #94a3b8; }

/* ── Light mode mobile nav overlay ── */
@media (max-width: 768px) {
  html.light .nav-links {
    background: rgba(255, 255, 255, 0.99);
  }
}