/* =========================================================
   Nguyen Trong Bach — Portfolio
   Design system: deep navy + white + light gray + cyan/blue accent
   ========================================================= */

:root {
  /* Surface */
  --navy-950: #050b16;
  --navy-900: #07101f;
  --navy-800: #0a1929;
  --navy-700: #0f2238;
  --navy-600: #14304f;
  --navy-500: #1f3a5f;
  --line:     #1c2a3d;

  /* Neutral */
  --gray-50:  #f8fafc;
  --gray-100: #f1f5f9;
  --gray-150: #ebf0f6;
  --gray-200: #e2e8f0;
  --gray-300: #cbd5e1;
  --gray-400: #94a3b8;
  --gray-500: #64748b;
  --gray-600: #475569;
  --gray-700: #334155;
  --gray-800: #1e293b;

  --white:    #ffffff;

  /* Accent */
  --accent:        #22d3ee;
  --accent-strong: #0ea5e9;
  --accent-deep:   #0284c7;
  --accent-violet: #818cf8;
  --accent-soft:   rgba(34, 211, 238, 0.12);
  --accent-grad:   linear-gradient(135deg, #22d3ee 0%, #0ea5e9 60%, #818cf8 100%);

  /* Effects */
  --shadow-xs: 0 1px 2px rgba(7, 16, 31, 0.05);
  --shadow-sm: 0 1px 2px rgba(7, 16, 31, 0.06), 0 1px 1px rgba(7, 16, 31, 0.04);
  --shadow-md: 0 6px 18px rgba(7, 16, 31, 0.08), 0 2px 6px rgba(7, 16, 31, 0.04);
  --shadow-lg: 0 16px 40px rgba(7, 16, 31, 0.12);
  --shadow-xl: 0 28px 60px rgba(7, 16, 31, 0.18), 0 8px 20px rgba(7, 16, 31, 0.08);
  --ring-accent: 0 0 0 3px rgba(34, 211, 238, 0.35);

  /* Radius */
  --radius-xs: 4px;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-xl: 22px;
  --radius-full: 999px;

  /* Spacing scale (used via clamp/multiples) */
  --space-section: 96px;

  /* Layout */
  --container: 1180px;

  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  --font-mono: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;

  /* Motion */
  --ease: cubic-bezier(0.4, 0, 0.2, 1);
  --t-fast: 0.15s var(--ease);
  --t-base: 0.25s var(--ease);
  --t-slow: 0.4s var(--ease);
}

/* ---------- Reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  scroll-padding-top: 88px; /* offset for sticky navbar */
}
body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.65;
  color: var(--gray-800);
  background: var(--white);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
img, svg { max-width: 100%; display: block; }
a {
  color: inherit;
  text-decoration: none;
  transition: color var(--t-base);
}
a:hover { color: var(--accent-strong); }
ul { list-style: none; padding: 0; margin: 0; }
h1, h2, h3, h4 { color: var(--navy-800); font-weight: 700; line-height: 1.25; margin: 0; }
p { margin: 0 0 1em; color: var(--gray-700); }
dl, dd { margin: 0; }

/* ---------- A11y helpers ---------- */
:focus { outline: none; }
:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: var(--radius-xs);
}
.skip-link {
  position: absolute;
  left: 12px;
  top: -48px;
  z-index: 200;
  background: var(--navy-800);
  color: var(--white);
  padding: 10px 16px;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 0.9rem;
  transition: top var(--t-base);
}
.skip-link:focus { top: 12px; color: var(--white); }

/* ---------- Layout ---------- */
.container {
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px;
}

.section {
  padding: var(--space-section) 0;
  background: var(--white);
}
.section-alt {
  background: var(--gray-50);
  position: relative;
}
.section-alt::before {
  content: '';
  position: absolute;
  inset: 0 0 auto 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--gray-200), transparent);
}

.section-eyebrow {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent-strong);
  margin: 0 0 12px;
}
.section-title {
  font-size: clamp(1.85rem, 3vw, 2.5rem);
  letter-spacing: -0.02em;
  margin-bottom: 40px;
  position: relative;
  display: inline-block;
  color: var(--navy-900);
}
.section-title::after {
  content: '';
  display: block;
  width: 56px;
  height: 3px;
  background: var(--accent-grad);
  margin-top: 12px;
  border-radius: 2px;
}
.section-intro {
  font-size: 1.02rem;
  color: var(--gray-600);
  max-width: 720px;
  margin: -20px 0 36px;
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 22px;
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: 0.95rem;
  font-family: inherit;
  letter-spacing: 0.01em;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform var(--t-base), background var(--t-base), border-color var(--t-base), color var(--t-base), box-shadow var(--t-base);
  white-space: nowrap;
}
.btn:focus-visible { box-shadow: var(--ring-accent); outline: none; }

.btn-primary {
  background: var(--navy-800);
  color: var(--white);
  border-color: var(--navy-800);
}
.btn-primary:hover {
  background: var(--accent-strong);
  border-color: var(--accent-strong);
  color: var(--white);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn-secondary {
  background: var(--accent);
  color: var(--navy-900);
  border-color: var(--accent);
}
.btn-secondary:hover {
  background: var(--white);
  color: var(--navy-900);
  border-color: var(--white);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn-ghost {
  background: transparent;
  color: var(--white);
  border-color: rgba(255, 255, 255, 0.25);
}
.btn-ghost:hover {
  background: rgba(255, 255, 255, 0.08);
  border-color: var(--white);
  color: var(--white);
  transform: translateY(-1px);
}

.btn-large {
  padding: 16px 28px;
  font-size: 1.02rem;
  border-radius: var(--radius-lg);
}

.btn-small {
  padding: 8px 14px;
  font-size: 0.85rem;
  border-radius: var(--radius-sm);
  background: var(--white);
  border: 1px solid var(--gray-300);
  color: var(--navy-800);
  font-weight: 600;
}
.btn-small:hover {
  background: var(--navy-800);
  color: var(--white);
  border-color: var(--navy-800);
}
.btn-small-primary {
  background: var(--navy-800);
  color: var(--white);
  border-color: var(--navy-800);
}
.btn-small-primary:hover {
  background: var(--accent-strong);
  border-color: var(--accent-strong);
}

/* Light surface buttons used inside Contact/CV sections (over white card) */
.section:not(.hero) .btn-ghost,
.cv-side .btn-ghost {
  color: var(--navy-800);
  border-color: var(--gray-300);
}
.section:not(.hero) .btn-ghost:hover,
.cv-side .btn-ghost:hover {
  background: var(--gray-50);
  border-color: var(--navy-800);
  color: var(--navy-800);
}

/* ---------- Navbar ---------- */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.78);
  backdrop-filter: saturate(180%) blur(14px);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid transparent;
  transition: border-color var(--t-base), box-shadow var(--t-base), background var(--t-base);
}
.navbar.scrolled {
  background: rgba(255, 255, 255, 0.92);
  border-bottom-color: var(--gray-200);
  box-shadow: var(--shadow-sm);
}
.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 68px;
  padding-top: 12px;
  padding-bottom: 12px;
}
.nav-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  font-weight: 700;
  color: var(--navy-800);
}
.nav-logo:hover { color: var(--navy-800); }
.logo-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--navy-800);
  overflow: hidden;
  border: 2px solid var(--accent);
  box-shadow: 0 2px 10px rgba(34, 211, 238, 0.25);
  flex-shrink: 0;
}
.logo-mark img { width: 100%; height: 100%; object-fit: cover; display: block; }
.logo-text { font-size: 0.98rem; }

.nav-links {
  display: flex;
  align-items: center;
  gap: 24px;
}
.nav-links a {
  position: relative;
  font-size: 0.92rem;
  color: var(--gray-700);
  font-weight: 500;
  padding: 6px 0;
}
.nav-links a:hover { color: var(--navy-800); }
.nav-links a.active { color: var(--navy-900); }
.nav-links a.active::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--accent-grad);
  border-radius: 2px;
}
.nav-cv {
  padding: 9px 18px;
  background: var(--navy-800);
  color: var(--white) !important;
  border-radius: var(--radius-md);
  font-weight: 600;
  transition: background var(--t-base), transform var(--t-base);
}
.nav-cv::after { display: none !important; }
.nav-cv:hover {
  background: var(--accent-strong);
  color: var(--white) !important;
  transform: translateY(-1px);
}

.nav-toggle {
  display: none;
  width: 42px;
  height: 42px;
  background: transparent;
  border: 1px solid var(--gray-300);
  border-radius: var(--radius-sm);
  padding: 0;
  cursor: pointer;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 5px;
}
.nav-toggle span {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--navy-800);
  border-radius: 2px;
  transition: transform var(--t-base), opacity var(--t-base);
}
.nav-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ---------- Hero ---------- */
.hero {
  position: relative;
  padding: 120px 0 100px;
  background: radial-gradient(ellipse at top, #0f2238 0%, #0a1929 50%, #07101f 100%);
  color: var(--white);
  overflow: hidden;
}
.hero-bg {
  position: absolute;
  inset: 0;
  pointer-events: none;
}
.hero-grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.035) 1px, transparent 1px);
  background-size: 48px 48px;
  mask-image: radial-gradient(ellipse 70% 60% at 50% 30%, #000 30%, transparent 80%);
  -webkit-mask-image: radial-gradient(ellipse 70% 60% at 50% 30%, #000 30%, transparent 80%);
}
.hero-glow {
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
  opacity: 0.55;
}
.hero-glow-1 {
  top: -120px; right: -100px;
  width: 460px; height: 460px;
  background: radial-gradient(circle, rgba(34, 211, 238, 0.45), transparent 70%);
}
.hero-glow-2 {
  bottom: -160px; left: -120px;
  width: 520px; height: 520px;
  background: radial-gradient(circle, rgba(129, 140, 248, 0.35), transparent 70%);
}

.hero-container {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: minmax(0, 1.5fr) minmax(0, 1fr);
  gap: 56px;
  align-items: center;
}
.hero-content { min-width: 0; max-width: 720px; }

.hero-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  margin: 0 0 22px;
  padding: 6px 14px;
  background: rgba(34, 211, 238, 0.08);
  border: 1px solid rgba(34, 211, 238, 0.25);
  border-radius: var(--radius-full);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
}
.status-dot {
  width: 8px; height: 8px; border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 4px rgba(34, 211, 238, 0.2);
  flex-shrink: 0;
  animation: pulse 2.4s var(--ease) infinite;
}
@keyframes pulse {
  0%, 100% { box-shadow: 0 0 0 0 rgba(34, 211, 238, 0.4); }
  50%      { box-shadow: 0 0 0 6px rgba(34, 211, 238, 0); }
}

.hero-title {
  font-size: clamp(2.2rem, 5vw, 3.8rem);
  letter-spacing: -0.03em;
  color: var(--white);
  margin: 0 0 24px;
  font-weight: 800;
  line-height: 1.05;
}
.accent-gradient {
  background: var(--accent-grad);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
}
.hero-subtitle {
  font-size: clamp(1rem, 1.5vw, 1.12rem);
  color: var(--gray-300);
  max-width: 640px;
  line-height: 1.7;
  margin: 0 0 28px;
}
.hero-subtitle strong { color: var(--white); font-weight: 600; }

.hero-badges {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 32px;
}
.badge-chip {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  letter-spacing: 0.06em;
  padding: 6px 12px;
  border-radius: var(--radius-full);
  background: rgba(255, 255, 255, 0.06);
  color: var(--gray-200);
  border: 1px solid rgba(255, 255, 255, 0.12);
  white-space: nowrap;
}
.badge-chip-accent {
  background: rgba(34, 211, 238, 0.14);
  color: var(--accent);
  border-color: rgba(34, 211, 238, 0.4);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}
.hero-actions .btn-primary {
  background: var(--white);
  color: var(--navy-900);
  border-color: var(--white);
}
.hero-actions .btn-primary:hover {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--navy-900);
}

/* Hero Card (Quick Facts) */
.hero-card {
  position: relative;
  border-radius: var(--radius-xl);
  padding: 28px;
  background:
    linear-gradient(135deg, rgba(255, 255, 255, 0.08), rgba(255, 255, 255, 0.02));
  border: 1px solid rgba(255, 255, 255, 0.12);
  backdrop-filter: blur(16px) saturate(140%);
  -webkit-backdrop-filter: blur(16px) saturate(140%);
  box-shadow: var(--shadow-xl);
  overflow: hidden;
}
.hero-card::before {
  content: '';
  position: absolute;
  inset: -1px;
  border-radius: inherit;
  padding: 1px;
  background: linear-gradient(135deg, rgba(34, 211, 238, 0.5), rgba(255, 255, 255, 0.05) 50%, rgba(129, 140, 248, 0.4));
  -webkit-mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  -webkit-mask-composite: xor;
  mask-composite: exclude;
  pointer-events: none;
}
.hero-card-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-bottom: 16px;
  margin-bottom: 18px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}
.hero-card-eyebrow {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent);
}
.hero-card-status {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.78rem;
  color: var(--gray-300);
  font-family: var(--font-mono);
}
.hero-facts { display: grid; gap: 16px; }
.hero-fact {
  display: flex;
  flex-direction: column;
  gap: 2px;
}
.hero-fact dt {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--gray-400);
}
.hero-fact dd {
  color: var(--white);
  font-weight: 600;
  font-size: 0.97rem;
}

/* ---------- About ---------- */
.about-grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr;
  gap: 48px;
  align-items: start;
}
.about-text p {
  font-size: 1.02rem;
  color: var(--gray-700);
}
.about-text strong { color: var(--navy-800); font-weight: 600; }

.about-cards {
  display: grid;
  gap: 14px;
}
.about-mini-card {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-lg);
  padding: 22px;
  box-shadow: var(--shadow-xs);
  transition: transform var(--t-base), box-shadow var(--t-base), border-color var(--t-base);
}
.about-mini-card:hover {
  transform: translateY(-3px);
  border-color: var(--accent);
  box-shadow: var(--shadow-md);
}
.about-mini-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 38px;
  height: 38px;
  border-radius: 10px;
  background: var(--accent-soft);
  color: var(--accent-strong);
  margin-bottom: 12px;
}
.about-mini-icon svg { width: 20px; height: 20px; }
.about-mini-card h3 { font-size: 1rem; font-weight: 600; margin-bottom: 6px; }
.about-mini-card p { font-size: 0.9rem; color: var(--gray-600); margin: 0; }

/* ---------- Timeline ---------- */
.timeline {
  position: relative;
  padding-left: 28px;
  border-left: 2px solid var(--gray-200);
}
.timeline-item { position: relative; padding-bottom: 36px; }
.timeline-item:last-child { padding-bottom: 0; }
.timeline-dot {
  position: absolute;
  left: -36px;
  top: 6px;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 4px rgba(34, 211, 238, 0.18);
}
.timeline-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 6px 16px;
  margin-bottom: 4px;
}
.timeline-head h3 { font-size: 1.12rem; font-weight: 600; }
.timeline-date {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--gray-500);
  letter-spacing: 0.03em;
  background: var(--gray-100);
  padding: 4px 10px;
  border-radius: var(--radius-sm);
}
.section-alt .timeline-date { background: var(--white); }
.timeline-sub {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--accent-strong);
  font-weight: 500;
  margin: 0 0 8px;
  font-size: 0.92rem;
}
.timeline-sub svg { width: 14px; height: 14px; }

.edu-stats {
  display: flex;
  flex-wrap: wrap;
  gap: 18px;
  margin: 14px 0 18px;
  padding: 16px 18px;
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-md);
}
.edu-stat { display: flex; flex-direction: column; }
.edu-stat-value {
  font-family: var(--font-mono);
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--navy-800);
}
.edu-stat-value small { font-size: 0.78rem; color: var(--gray-500); font-weight: 400; }
.edu-stat-label {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--gray-500);
}

/* ---------- Master's Card ---------- */
.masters-card {
  position: relative;
  background: linear-gradient(135deg, #0a1929 0%, #14304f 100%);
  color: var(--gray-100);
  border-radius: var(--radius-xl);
  padding: 44px;
  box-shadow: var(--shadow-lg);
  overflow: hidden;
}
.masters-glow {
  position: absolute;
  top: -120px; right: -80px;
  width: 320px; height: 320px;
  background: radial-gradient(circle, rgba(34, 211, 238, 0.4), transparent 65%);
  border-radius: 50%;
  filter: blur(50px);
}
.masters-head {
  position: relative;
  margin-bottom: 18px;
}
.masters-tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent);
  background: var(--accent-soft);
  padding: 6px 12px;
  border-radius: var(--radius-full);
  border: 1px solid rgba(34, 211, 238, 0.3);
  margin-bottom: 14px;
}
.masters-head h3 {
  color: var(--white);
  font-size: clamp(1.25rem, 2.3vw, 1.6rem);
  font-weight: 700;
}
.masters-card p {
  color: var(--gray-200);
  position: relative;
  font-size: 1.02rem;
}
.masters-card strong { color: var(--white); }
.masters-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 22px;
  position: relative;
}
.masters-tags li {
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.15);
  color: var(--gray-100);
  padding: 7px 14px;
  border-radius: var(--radius-full);
  font-size: 0.85rem;
  font-weight: 500;
}

/* ---------- Interests ---------- */
.interests-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 16px;
}
.interest {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-lg);
  padding: 24px;
  transition: transform var(--t-base), border-color var(--t-base), box-shadow var(--t-base);
}
.interest:hover {
  transform: translateY(-3px);
  border-color: var(--accent);
  box-shadow: var(--shadow-md);
}
.interest-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  border-radius: 10px;
  background: var(--accent-soft);
  color: var(--accent-strong);
  margin-bottom: 14px;
  transition: background var(--t-base), color var(--t-base);
}
.interest-icon svg { width: 22px; height: 22px; }
.interest:hover .interest-icon {
  background: var(--accent-strong);
  color: var(--white);
}
.interest h3 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--navy-800);
  margin-bottom: 6px;
}
.interest p {
  font-size: 0.88rem;
  color: var(--gray-600);
  margin: 0;
  line-height: 1.55;
}

/* ---------- Skills ---------- */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
}
.skill-card {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-lg);
  padding: 26px;
  transition: transform var(--t-base), box-shadow var(--t-base), border-color var(--t-base);
}
.skill-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
  border-color: var(--gray-300);
}
.skill-card-head {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
}
.skill-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 10px;
  background: var(--accent-soft);
  color: var(--accent-strong);
}
.skill-icon svg { width: 18px; height: 18px; }
.skill-card-head h3 { font-size: 1.02rem; font-weight: 600; }

.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}
.tag-list li {
  background: var(--gray-100);
  color: var(--navy-800);
  font-size: 0.82rem;
  font-weight: 500;
  padding: 5px 12px;
  border-radius: var(--radius-full);
  border: 1px solid var(--gray-200);
  transition: background var(--t-fast), color var(--t-fast), border-color var(--t-fast);
}
.tag-list li:hover {
  background: var(--accent-soft);
  border-color: var(--accent);
}

/* ---------- Projects ---------- */
.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 28px;
  padding: 8px;
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-full);
  box-shadow: var(--shadow-xs);
  width: fit-content;
  max-width: 100%;
}
.filter-chip {
  background: transparent;
  border: none;
  padding: 8px 16px;
  font-size: 0.86rem;
  font-weight: 500;
  font-family: inherit;
  color: var(--gray-600);
  cursor: pointer;
  border-radius: var(--radius-full);
  transition: background var(--t-base), color var(--t-base);
  white-space: nowrap;
}
.filter-chip:hover { color: var(--navy-800); background: var(--gray-100); }
.filter-chip.is-active {
  background: var(--navy-800);
  color: var(--white);
}
.filter-chip:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
  gap: 24px;
}
.project-card {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-xl);
  padding: 28px;
  display: flex;
  flex-direction: column;
  transition: transform var(--t-slow), box-shadow var(--t-slow), border-color var(--t-slow);
  position: relative;
  overflow: hidden;
}
.project-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 3px;
  background: var(--accent-grad);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--t-slow);
}
.project-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-xl);
  border-color: var(--gray-300);
}
.project-card:hover::before { transform: scaleX(1); }
.project-card.filter-hidden { display: none; }

.project-head { margin-bottom: 12px; }
.project-tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent-strong);
  background: var(--accent-soft);
  padding: 4px 10px;
  border-radius: var(--radius-xs);
  margin-bottom: 12px;
}
.project-head h3 {
  font-size: 1.18rem;
  line-height: 1.35;
}
.project-desc {
  font-size: 0.94rem;
  color: var(--gray-700);
  margin-bottom: 16px;
}

.project-metrics {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 8px;
  margin-bottom: 18px;
  padding: 14px;
  background: linear-gradient(135deg, var(--gray-50), var(--white));
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-md);
}
.metric { display: flex; flex-direction: column; align-items: flex-start; }
.metric-value {
  font-family: var(--font-mono);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--accent-strong);
  line-height: 1.1;
}
.metric-value small { font-size: 0.7em; font-weight: 500; color: var(--gray-500); }
.metric-label {
  font-size: 0.7rem;
  color: var(--gray-600);
  line-height: 1.3;
  margin-top: 4px;
}

.project-highlights {
  margin: 0 0 18px;
  font-size: 0.88rem;
  color: var(--gray-700);
}
.project-highlights li {
  position: relative;
  padding: 4px 0 4px 18px;
  line-height: 1.5;
}
.project-highlights li::before {
  content: '';
  position: absolute;
  left: 0; top: 12px;
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--accent);
}
.project-highlights strong { color: var(--navy-800); }
.project-card .tag-list { margin-bottom: 18px; }

.project-actions {
  margin-top: auto;
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}
.project-actions .btn-small svg { flex-shrink: 0; }
.project-actions-multi .btn-small {
  flex: 1 1 auto;
  min-width: 110px;
  text-align: center;
  justify-content: center;
}

.projects-empty {
  text-align: center;
  color: var(--gray-500);
  padding: 40px 0;
  font-style: italic;
}

/* ---------- Coursework ---------- */
.coursework-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 12px;
}
.coursework-grid li {
  padding: 14px 18px;
  background: var(--gray-50);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-md);
  font-size: 0.94rem;
  font-weight: 500;
  color: var(--navy-800);
  transition: background var(--t-base), border-color var(--t-base), transform var(--t-base);
}
.coursework-grid li:hover {
  background: var(--white);
  border-color: var(--accent);
  transform: translateY(-2px);
}

/* ---------- CV section ---------- */
.cv-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.4fr);
  gap: 32px;
  align-items: stretch;
}
.cv-side {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-xl);
  padding: 28px;
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
}
.cv-side h3 { font-size: 1.15rem; margin-bottom: 12px; }
.cv-side > p { font-size: 0.96rem; color: var(--gray-700); }

.cv-includes {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 6px 12px;
  margin: 8px 0 18px;
}
.cv-includes li {
  position: relative;
  padding-left: 18px;
  font-size: 0.88rem;
  color: var(--gray-700);
}
.cv-includes li::before {
  content: '';
  position: absolute;
  left: 0; top: 0.55em;
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--accent);
}

.cv-meta {
  margin: 6px 0 22px;
  border-top: 1px dashed var(--gray-200);
}
.cv-meta li {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  padding: 12px 0;
  border-bottom: 1px dashed var(--gray-200);
  font-size: 0.92rem;
}
.cv-meta li span { color: var(--gray-500); }
.cv-meta li strong { color: var(--navy-800); font-weight: 600; text-align: right; }

.cv-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: auto;
}
.cv-actions .btn { flex: 1 1 auto; min-width: 140px; }

.cv-viewer { display: flex; flex-direction: column; }
.cv-viewer-frame {
  position: relative;
  width: 100%;
  height: 720px;
  background: var(--gray-100);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-xl);
  overflow: hidden;
  box-shadow: var(--shadow-md);
}
.cv-viewer-frame object,
.cv-viewer-frame iframe {
  width: 100%; height: 100%; border: 0; display: block;
}
.cv-fallback {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  height: 100%;
  padding: 28px;
  gap: 16px;
  color: var(--gray-600);
}
.cv-hint {
  margin: 12px 0 0;
  font-size: 0.85rem;
  color: var(--gray-500);
  text-align: center;
}
.cv-hint em { color: var(--navy-800); font-style: normal; font-weight: 500; }

/* ---------- Contact ---------- */
.contact-cta {
  background: linear-gradient(135deg, var(--navy-800) 0%, var(--navy-600) 100%);
  color: var(--white);
  border-radius: var(--radius-xl);
  padding: 40px;
  margin-bottom: 32px;
  position: relative;
  overflow: hidden;
  box-shadow: var(--shadow-lg);
}
.contact-cta::before {
  content: '';
  position: absolute;
  top: -100px; right: -80px;
  width: 280px; height: 280px;
  background: radial-gradient(circle, rgba(34, 211, 238, 0.35), transparent 65%);
  border-radius: 50%;
  filter: blur(40px);
}
.contact-cta h3 {
  color: var(--white);
  font-size: clamp(1.2rem, 2vw, 1.5rem);
  margin-bottom: 12px;
  position: relative;
}
.contact-cta p {
  color: var(--gray-200);
  max-width: 600px;
  position: relative;
  margin-bottom: 24px;
}
.contact-cta .btn-primary {
  background: var(--accent);
  color: var(--navy-900);
  border-color: var(--accent);
  position: relative;
}
.contact-cta .btn-primary:hover {
  background: var(--white);
  color: var(--navy-900);
  border-color: var(--white);
}

.contact-channels {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 12px;
}
.contact-channel {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 16px 18px;
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-lg);
  color: var(--navy-800);
  transition: transform var(--t-base), border-color var(--t-base), box-shadow var(--t-base);
}
.contact-channel:hover {
  transform: translateY(-2px);
  border-color: var(--accent);
  box-shadow: var(--shadow-md);
  color: var(--navy-800);
}
.contact-channel-static { cursor: default; }
.contact-channel-static:hover { transform: none; box-shadow: none; border-color: var(--gray-200); }

.contact-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  border-radius: 10px;
  background: var(--accent-soft);
  color: var(--accent-strong);
  flex-shrink: 0;
}
.contact-icon svg { width: 20px; height: 20px; }
.contact-channel-body {
  display: flex;
  flex-direction: column;
  min-width: 0;
}
.contact-channel-label {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--gray-500);
}
.contact-channel-value {
  font-weight: 600;
  font-size: 0.94rem;
  color: var(--navy-800);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* ---------- Footer ---------- */
.footer {
  background: var(--navy-950);
  color: var(--gray-300);
  padding: 44px 0 28px;
}
.footer-container {
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: center;
  gap: 18px;
}
.footer-left { display: flex; flex-direction: column; }
.footer-logo { color: var(--white); font-weight: 600; font-size: 1.02rem; }
.footer-sub { color: var(--gray-400); font-size: 0.86rem; margin-top: 2px; }
.footer-right {
  display: flex;
  gap: 22px;
  font-size: 0.9rem;
  flex-wrap: wrap;
}
.footer-right a { color: var(--gray-300); }
.footer-right a:hover { color: var(--accent); }
.footer-copy {
  grid-column: 1 / -1;
  margin: 20px 0 0;
  padding-top: 20px;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  font-size: 0.82rem;
  color: var(--gray-500);
}

/* ---------- Reveal-on-scroll ---------- */
.reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.55s var(--ease), transform 0.55s var(--ease);
  will-change: opacity, transform;
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
  .status-dot { animation: none; }
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    transition-duration: 0.001ms !important;
  }
}

/* ---------- Responsive ---------- */
@media (max-width: 1024px) {
  .hero-container { gap: 40px; }
  .about-grid { grid-template-columns: 1fr; gap: 28px; }
}

@media (max-width: 960px) {
  :root { --space-section: 72px; }
  .hero { padding: 96px 0 80px; }
  .hero-container {
    grid-template-columns: 1fr;
    gap: 36px;
  }
  .hero-content { max-width: none; }
  .contact-cta { padding: 32px 26px; }
  .cv-grid { grid-template-columns: 1fr; }
  .cv-viewer-frame { height: 560px; }
}

@media (max-width: 768px) {
  .nav-toggle { display: inline-flex; }
  .nav-links {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--white);
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 8px 16px 16px;
    border-bottom: 1px solid var(--gray-200);
    box-shadow: var(--shadow-md);
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--t-slow), padding var(--t-slow);
  }
  .nav-links.open {
    max-height: 600px;
    padding: 8px 16px 20px;
  }
  .nav-links a {
    padding: 13px 4px;
    border-bottom: 1px solid var(--gray-100);
    font-size: 1rem;
  }
  .nav-links a.active::after { display: none; }
  .nav-links a.active { color: var(--accent-strong); }
  .nav-links a:last-child { border-bottom: none; }
  .nav-cv { margin-top: 8px; text-align: center; }
  .logo-text { display: none; }
  .footer-container { grid-template-columns: 1fr; }
  .masters-card { padding: 32px 26px; }
  .project-metrics { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 560px) {
  :root { --space-section: 60px; }
  .container { padding: 0 18px; }
  .hero { padding: 80px 0 60px; }
  .hero-title { font-size: 2.1rem; }
  .hero-eyebrow { font-size: 0.74rem; padding: 5px 12px; }
  .hero-card { padding: 22px; }
  .hero-actions .btn { flex: 1 1 calc(50% - 5px); justify-content: center; padding: 11px 14px; font-size: 0.88rem; }
  .skill-card, .project-card, .about-mini-card, .cv-side { padding: 22px; }
  .timeline { padding-left: 22px; }
  .timeline-dot { left: -30px; }
  .timeline-head { flex-direction: column; align-items: flex-start; gap: 4px; }
  .contact-channel-value { font-size: 0.88rem; }
  .filter-bar { padding: 6px; gap: 4px; }
  .filter-chip { padding: 7px 12px; font-size: 0.82rem; }
  .project-metrics { padding: 12px; }
  .cv-includes { grid-template-columns: 1fr; }
  .cv-viewer-frame { height: 480px; }
}

@media (max-width: 430px) {
  .hero-title { font-size: 1.85rem; }
  .section-title { font-size: 1.65rem; }
  .hero-actions .btn { flex: 1 1 100%; }
}