:root {
  --bg: #f4f8fc;
  --bg-soft: #eef5fb;
  --white: #ffffff;
  --primary: #1f4e79;
  --primary-dark: #173a5c;
  --primary-light: #2f6ea8;
  --accent: #4c8bf5;
  --accent-soft: #dceaff;
  --text: #1c2430;
  --muted: #5f6b7a;
  --border: #d9e2ec;
  --shadow-sm: 0 6px 18px rgba(16, 24, 40, 0.06);
  --shadow: 0 14px 35px rgba(16, 24, 40, 0.08);
  --shadow-lg: 0 20px 45px rgba(16, 24, 40, 0.12);
  --radius: 18px;
  --radius-sm: 14px;
  --max-width: 1120px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial, sans-serif;
  background:
    radial-gradient(circle at top left, rgba(76, 139, 245, 0.08), transparent 25%),
    linear-gradient(180deg, #f8fbff 0%, #f4f8fc 45%, #eef4f8 100%);
  color: var(--text);
  line-height: 1.75;
}

a {
  color: var(--primary);
  text-decoration: none;
  transition: all 0.25s ease;
}

a:hover {
  text-decoration: none;
}

.container {
  width: min(92%, var(--max-width));
  margin: 0 auto;
}

/* Header */
.header {
  background: rgba(255, 255, 255, 0.88);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(217, 226, 236, 0.8);
  position: sticky;
  top: 0;
  z-index: 1000;
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 76px;
  position: relative;
}

.logo {
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--primary-dark);
  letter-spacing: -0.02em;
}

.nav-links {
  list-style: none;
  display: flex;
  gap: 1.35rem;
}

.nav-links a {
  color: var(--text);
  font-weight: 600;
  font-size: 0.95rem;
  position: relative;
}

.nav-links a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -0.3rem;
  width: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--accent), var(--primary));
  border-radius: 999px;
  transition: width 0.25s ease;
}

.nav-links a:hover::after {
  width: 100%;
}

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

.menu-toggle {
  display: none;
  font-size: 1.5rem;
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: 12px;
  width: 44px;
  height: 44px;
  cursor: pointer;
  box-shadow: var(--shadow-sm);
  color: var(--primary-dark);
}

/* Hero */
.hero {
  padding: 90px 0 70px;
  background: linear-gradient(135deg, #eef5ff, #f8fbff);
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: "";
  position: absolute;
  width: 320px;
  height: 320px;
  background: rgba(76, 139, 245, 0.08);
  border-radius: 50%;
  top: -80px;
  right: -80px;
  filter: blur(10px);
}

.hero-content {
  display: grid;
  grid-template-columns: 1.5fr 1fr;
  gap: 2rem;
  align-items: center;
  position: relative;
  z-index: 1;
}

.eyebrow {
  display: inline-block;
  color: var(--accent);
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  margin-bottom: 1rem;
  font-size: 0.84rem;
  background: rgba(76, 139, 245, 0.1);
  padding: 0.45rem 0.85rem;
  border-radius: 999px;
}

.hero h1 {
  font-size: clamp(2.4rem, 4.8vw, 4rem);
  line-height: 1.08;
  color: var(--primary-dark);
  margin-bottom: 1rem;
  letter-spacing: -0.03em;
}

.lead {
  font-size: 1.08rem;
  color: var(--muted);
  max-width: 700px;
}

.hero-buttons {
  display: flex;
  gap: 1rem;
  margin-top: 1.8rem;
  flex-wrap: wrap;
}

.btn {
  display: inline-block;
  padding: 0.95rem 1.35rem;
  border-radius: 999px;
  font-weight: 700;
  transition: all 0.25s ease;
  box-shadow: var(--shadow-sm);
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary), var(--primary-light));
  color: white;
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow);
  color: white;
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.95);
  border: 1px solid var(--border);
  color: var(--text);
}

.btn-secondary:hover {
  transform: translateY(-2px);
  border-color: var(--primary);
  box-shadow: var(--shadow);
}

/* Cards */
.hero-card,
.card {
  background: rgba(255, 255, 255, 0.9);
  border: 1px solid rgba(217, 226, 236, 0.9);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  padding: 1.6rem;
  transition: all 0.28s ease;
}

.hero-card:hover,
.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow);
}

.hero-card h2,
.card h3 {
  margin-bottom: 1rem;
  color: var(--primary-dark);
  letter-spacing: -0.02em;
}

.hero-card ul {
  list-style: none;
}

.hero-card li {
  margin-bottom: 0.75rem;
}

/* Sections */
.section {
  padding: 78px 0;
}

.section-alt {
  background: linear-gradient(180deg, #eef4f8 0%, #f4f8fc 100%);
}

.section-heading {
  margin-bottom: 2rem;
}

.section-tag {
  color: var(--accent);
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 1.3px;
  margin-bottom: 0.55rem;
  font-size: 0.82rem;
}

.section-heading h2 {
  font-size: clamp(1.9rem, 3vw, 2.6rem);
  color: var(--primary-dark);
  letter-spacing: -0.03em;
}

/* Grid */
.grid-3,
.grid-2 {
  display: grid;
  gap: 1.5rem;
}

.grid-3 {
  grid-template-columns: repeat(3, 1fr);
}

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

.skill-card,
.cert-card {
  height: 100%;
}

.top-gap {
  margin-top: 1.5rem;
}

.card p {
  color: var(--muted);
}

.card p + p {
  margin-top: 0.9rem;
}

/* Links inside cards */
.cert-link {
  display: inline-block;
  margin-top: 1rem;
  font-weight: 700;
  padding: 0.75rem 1.1rem;
  border-radius: 999px;
  background: rgba(76, 139, 245, 0.08);
  border: 1px solid rgba(76, 139, 245, 0.12);
}

.cert-link:hover {
  background: var(--primary);
  color: white;
  transform: translateY(-2px);
}

/* Note */
.note {
  margin-top: 1rem;
  color: var(--muted);
  font-size: 0.95rem;
}

/* Contact */
.contact-list p {
  margin-top: 0.8rem;
}

/* Table of contents */
#toc .card {
  padding: 2rem;
}

.toc-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.2rem;
}

.toc-link {
  display: block;
  padding: 1.15rem 1.2rem;
  background: linear-gradient(135deg, #f8fbff, #eef5ff);
  border: 1px solid var(--border);
  border-radius: 16px;
  font-weight: 700;
  color: var(--primary-dark);
  position: relative;
  overflow: hidden;
  transition: all 0.28s ease;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
}

.toc-link:hover {
  transform: translateY(-5px);
  background: linear-gradient(135deg, #ebf3ff, #dceaff);
  border-color: var(--accent);
  box-shadow: var(--shadow);
}

.toc-link::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  width: 0;
  height: 100%;
  background: linear-gradient(180deg, var(--accent), var(--primary));
  transition: width 0.28s ease;
  border-radius: 16px 0 0 16px;
}

.toc-link:hover::before {
  width: 6px;
}

#toc .toc-link {
  opacity: 0;
  transform: translateY(20px);
  animation: fadeUp 0.6s ease forwards;
}

#toc .toc-link:nth-child(1) { animation-delay: 0.08s; }
#toc .toc-link:nth-child(2) { animation-delay: 0.16s; }
#toc .toc-link:nth-child(3) { animation-delay: 0.24s; }
#toc .toc-link:nth-child(4) { animation-delay: 0.32s; }
#toc .toc-link:nth-child(5) { animation-delay: 0.40s; }
#toc .toc-link:nth-child(6) { animation-delay: 0.48s; }
#toc .toc-link:nth-child(7) { animation-delay: 0.56s; }
#toc .toc-link:nth-child(8) { animation-delay: 0.64s; }
#toc .toc-link:nth-child(9) { animation-delay: 0.72s; }
#toc .toc-link:nth-child(10) { animation-delay: 0.80s; }

@keyframes fadeUp {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* References button */
.references-preview-card {
  text-align: center;
  padding: 2rem;
}

.references-btn {
  display: inline-block;
  margin-top: 1rem;
  padding: 0.9rem 1.45rem;
  background: linear-gradient(135deg, var(--primary), var(--primary-light));
  color: #fff;
  border-radius: 999px;
  font-weight: 700;
  border: 1px solid transparent;
  transition: all 0.28s ease;
  box-shadow: 0 10px 22px rgba(31, 78, 121, 0.16);
}

.references-btn:hover {
  color: #fff;
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}

/* Footer */
.footer {
  background: linear-gradient(135deg, var(--primary-dark), #102c47);
  color: white;
  padding: 24px 0;
}

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

/* Responsive */
@media (max-width: 900px) {
  .hero-content,
  .grid-3,
  .grid-2,
  .toc-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  .menu-toggle {
    display: block;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: 72px;
    right: 4%;
    background: rgba(255, 255, 255, 0.97);
    border: 1px solid var(--border);
    border-radius: 14px;
    box-shadow: var(--shadow);
    padding: 1rem;
    flex-direction: column;
    min-width: 230px;
    backdrop-filter: blur(10px);
  }

  .experience-list {
  margin-top: 1rem;
  padding-left: 1.2rem;
}

.experience-list li {
  margin-bottom: 0.6rem;
  color: var(--muted);
}

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

  .hero {
    padding-top: 72px;
  }

  .hero-card,
  .card,
  #toc .card {
    padding: 1.35rem;
  }

  .hero-buttons {
    flex-direction: column;
  }

  .btn,
  .references-btn {
    width: 100%;
    text-align: center;
  }
}