:root {
  --color-background: #0f172a;
  --color-gradient-start: #0b1120;
  --color-gradient-end: #111f3a;
  --color-surface: rgba(15, 23, 42, 0.75);
  --color-card: rgba(148, 163, 184, 0.08);
  --color-card-border: rgba(148, 163, 184, 0.2);
  --color-text: #f8fafc;
  --color-text-muted: #94a3b8;
  --color-accent: #38bdf8;
  --color-accent-strong: #0ea5e9;
  --color-outline: rgba(56, 189, 248, 0.35);
  --shadow-soft: 0 24px 48px rgba(8, 47, 73, 0.35);
  --shadow-sharp: 0 18px 36px rgba(7, 25, 47, 0.45);
  --container-max: 1140px;
}

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

html {
  scroll-behavior: smooth;
}

/* Accessibility: skip to content */
.skip-link {
  position: absolute;
  top: -3rem;
  left: 0;
  background: var(--color-accent);
  color: #0b1120;
  padding: 0.5rem 1rem;
  border-bottom-right-radius: 8px;
  z-index: 1050;
  font-weight: 600;
  transition: top 0.2s ease;
}

.skip-link:focus {
  top: 0;
  outline: none;
  box-shadow: 0 0 0 3px var(--color-outline);
}

body {
  margin: 0;
  font-family: "Inter", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: var(--color-text);
  background: radial-gradient(circle at 20% 20%, rgba(14, 165, 233, 0.18), transparent 40%),
    radial-gradient(circle at 80% 0%, rgba(56, 189, 248, 0.15), transparent 45%),
    linear-gradient(180deg, var(--color-gradient-start), var(--color-gradient-end));
  line-height: 1.65;
  min-height: 100vh;
}

a {
  color: var(--color-accent);
  transition: color 0.2s ease, opacity 0.2s ease;
}

a:hover,
a:focus {
  color: var(--color-accent-strong);
  text-decoration: none;
}

p {
  margin-bottom: 1rem;
  color: var(--color-text-muted);
}

h1,
h2,
h3,
h4,
h5,
h6 {
  margin: 0 0 0.75rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--color-text);
}

section {
  position: relative;
}

.container {
  max-width: var(--container-max);
}

/* Header & navigation */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1040;
  backdrop-filter: blur(12px);
  background: rgba(15, 23, 42, 0.85);
  border-bottom: 1px solid rgba(148, 163, 184, 0.12);
}

.navbar {
  padding: 1rem 0;
}

.navbar-brand {
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--color-text) !important;
}

.navbar-dark .navbar-toggler {
  border-color: rgba(148, 163, 184, 0.4);
}

.navbar-dark .navbar-toggler-icon {
  background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 30 30'%3e%3cpath stroke='rgba(148,163,184, 0.9)' stroke-linecap='round' stroke-miterlimit='10' stroke-width='2' d='M4 7h22M4 15h22M4 23h22'/%3e%3c/svg%3e");
}

.navbar-nav .nav-link {
  font-weight: 500;
  color: var(--color-text-muted);
  padding: 0.5rem 1rem;
  position: relative;
}

.navbar-nav .nav-link::after {
  content: "";
  position: absolute;
  left: 1rem;
  right: 1rem;
  bottom: 0.25rem;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--color-accent), transparent);
  transform: scaleX(0);
  transform-origin: center;
  transition: transform 0.2s ease;
}

.navbar-nav .nav-link:hover,
.navbar-nav .nav-link:focus {
  color: var(--color-text);
}

.navbar-nav .nav-link:hover::after,
.navbar-nav .nav-link:focus::after {
  transform: scaleX(1);
}

.hero {
  padding: 7rem 0 6rem;
  min-height: 100vh;
}

.hero-eyebrow {
  display: inline-block;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-accent);
  background: rgba(56, 189, 248, 0.12);
  padding: 0.4rem 0.75rem;
  border-radius: 999px;
  margin-bottom: 1rem;
}

.hero h1 {
  font-size: clamp(2.5rem, 5vw, 3.75rem);
  line-height: 1.1;
  margin-bottom: 1.5rem;
}

.hero .lead {
  font-size: 1.125rem;
  max-width: 42rem;
}

.hero-cta {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin: 2rem 0;
}

.hero-cta .btn {
  padding: 0.85rem 1.8rem;
  font-weight: 600;
  border-radius: 999px;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.btn-primary {
  background: linear-gradient(135deg, var(--color-accent-strong), #22d3ee);
  border: none;
  box-shadow: var(--shadow-soft);
}

.btn-primary:hover,
.btn-primary:focus {
  transform: translateY(-2px);
  box-shadow: var(--shadow-sharp);
}

.btn-outline-light {
  border: 1px solid rgba(148, 163, 184, 0.4);
  color: var(--color-text);
}

.btn-outline-light:hover,
.btn-outline-light:focus {
  background: rgba(148, 163, 184, 0.15);
  color: var(--color-text);
}

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

.highlight-card {
  background: var(--color-card);
  border: 1px solid var(--color-card-border);
  border-radius: 16px;
  padding: 1.5rem;
  min-width: 10rem;
  text-align: left;
  backdrop-filter: blur(14px);
}

.highlight-card .value {
  display: block;
  font-size: 2rem;
  font-weight: 700;
  color: var(--color-text);
}

.highlight-card .label {
  color: var(--color-text-muted);
  font-size: 0.95rem;
}

.hero-card {
  background: rgba(15, 23, 42, 0.65);
  border: 1px solid rgba(148, 163, 184, 0.18);
  border-radius: 24px;
  padding: 2.5rem;
  box-shadow: var(--shadow-soft);
  backdrop-filter: blur(18px);
}

.hero-card ul {
  padding-left: 1.2rem;
  color: var(--color-text-muted);
}

.hero-card li {
  margin-bottom: 0.6rem;
}

.hero-social {
  margin-top: 2rem;
  display: flex;
  gap: 0.75rem;
}

.social-link {
  width: 48px;
  height: 48px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  background: rgba(148, 163, 184, 0.12);
  border: 1px solid rgba(148, 163, 184, 0.2);
  color: var(--color-text);
  font-size: 1.35rem;
  transition: transform 0.2s ease, background 0.2s ease;
}

.social-link:hover,
.social-link:focus {
  transform: translateY(-3px);
  background: rgba(56, 189, 248, 0.15);
  color: var(--color-accent);
}

.section {
  padding: 6rem 0;
}

.section-heading {
  max-width: 640px;
  margin: 0 auto 3rem;
}

.section-heading h2 {
  font-size: clamp(2rem, 4vw, 2.5rem);
}

.eyebrow {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--color-accent);
  margin-bottom: 0.75rem;
}

.about-card {
  background: rgba(15, 23, 42, 0.55);
  border: 1px solid rgba(148, 163, 184, 0.18);
  border-radius: 20px;
  padding: 2rem;
  backdrop-filter: blur(12px);
}

.about-card ul {
  padding-left: 1.15rem;
  margin: 0;
  color: var(--color-text-muted);
}

.skills .row {
  gap: 1.5rem 0;
}

.skill-card {
  background: rgba(15, 23, 42, 0.6);
  border: 1px solid rgba(148, 163, 184, 0.18);
  border-radius: 20px;
  padding: 2.25rem;
  height: 100%;
  box-shadow: var(--shadow-soft);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.skill-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-sharp);
}

.skill-card h3 {
  font-size: 1.25rem;
}

.skill-card ul {
  padding-left: 1.2rem;
  color: var(--color-text-muted);
}

.experience {
  position: relative;
}

.timeline {
  position: relative;
  margin-top: 3rem;
  padding-left: 1.5rem;
  border-left: 1px solid rgba(148, 163, 184, 0.24);
}

.timeline::before {
  content: "";
  position: absolute;
  left: -9px;
  top: 0;
  bottom: 0;
  width: 18px;
  background: linear-gradient(180deg, rgba(56, 189, 248, 0.15), rgba(14, 165, 233, 0.05));
  border-radius: 999px;
}

.timeline-item {
  position: relative;
  padding: 1.5rem 2rem;
  margin-bottom: 2rem;
  background: rgba(15, 23, 42, 0.65);
  border: 1px solid rgba(148, 163, 184, 0.18);
  border-radius: 20px;
  backdrop-filter: blur(12px);
  box-shadow: var(--shadow-soft);
}

.timeline-item::before {
  content: "";
  position: absolute;
  left: -2.5rem;
  top: 1.75rem;
  width: 14px;
  height: 14px;
  background: linear-gradient(135deg, var(--color-accent-strong), #22d3ee);
  border-radius: 50%;
  box-shadow: 0 0 0 4px rgba(56, 189, 248, 0.2);
}

.timeline-meta {
  display: inline-block;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--color-accent);
  margin-bottom: 0.5rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.timeline-item ul {
  padding-left: 1.1rem;
  color: var(--color-text-muted);
}

.projects .row > [class*="col"] {
  margin-bottom: 2rem;
}

.project-card {
  background: rgba(15, 23, 42, 0.6);
  border: 1px solid rgba(148, 163, 184, 0.2);
  border-radius: 22px;
  padding: 2.5rem 2.25rem;
  height: 100%;
  box-shadow: var(--shadow-soft);
  display: flex;
  flex-direction: column;
  gap: 1rem;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.project-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-sharp);
}

.project-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.badge {
  border-radius: 999px;
  padding: 0.35rem 0.9rem;
  font-weight: 500;
  font-size: 0.75rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  background: rgba(56, 189, 248, 0.12);
  color: var(--color-accent);
}

.project-card ul {
  padding-left: 1.1rem;
  color: var(--color-text-muted);
}

.project-card .btn-link {
  align-self: flex-start;
  padding: 0;
  border: none;
  font-weight: 600;
  color: var(--color-accent);
}

.project-card .btn-link:hover,
.project-card .btn-link:focus {
  color: var(--color-accent-strong);
}

.contact {
  padding-bottom: 8rem;
}

.contact-card {
  background: rgba(15, 23, 42, 0.65);
  border: 1px solid rgba(148, 163, 184, 0.18);
  border-radius: 22px;
  padding: 2rem;
  box-shadow: var(--shadow-soft);
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.contact-card .btn {
  border-radius: 14px;
}

.btn-block {
  width: 100%;
}

.contact-meta {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  margin-top: 0.5rem;
  color: var(--color-text-muted);
}

.contact-meta i {
  color: var(--color-accent);
  margin-right: 0.5rem;
}

.site-footer {
  padding: 3rem 0;
  border-top: 1px solid rgba(148, 163, 184, 0.12);
  background: rgba(15, 23, 42, 0.8);
  backdrop-filter: blur(8px);
}

.footer-title {
  margin-bottom: 0;
  font-weight: 500;
  color: var(--color-text-muted);
}

.footer-social {
  display: flex;
  justify-content: flex-end;
  gap: 0.75rem;
}

.footer-social a {
  width: 42px;
  height: 42px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  background: rgba(148, 163, 184, 0.1);
  color: var(--color-text);
  transition: background 0.2s ease, transform 0.2s ease;
}

.footer-social a:hover,
.footer-social a:focus {
  background: rgba(56, 189, 248, 0.18);
  transform: translateY(-2px);
  color: var(--color-accent);
}

.footer-meta {
  margin-top: 2rem;
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  font-size: 0.9rem;
  color: var(--color-text-muted);
}

.back-to-top {
  position: fixed;
  right: 24px;
  bottom: 24px;
  width: 50px;
  height: 50px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--color-accent-strong), #22d3ee);
  color: var(--color-text);
  display: grid;
  place-items: center;
  box-shadow: var(--shadow-soft);
  opacity: 0;
  visibility: hidden;
  transition: transform 0.2s ease, opacity 0.2s ease, visibility 0.2s ease;
}

.back-to-top:hover,
.back-to-top:focus {
  transform: translateY(-3px);
  color: var(--color-text);
}

.back-to-top.is-visible {
  opacity: 1;
  visibility: visible;
}

#preloader {
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, 0.92);
  display: grid;
  place-items: center;
  z-index: 9999;
}

#preloader::after {
  content: "";
  width: 48px;
  height: 48px;
  border-radius: 50%;
  border: 3px solid rgba(56, 189, 248, 0.25);
  border-top-color: var(--color-accent);
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

::selection {
  background: rgba(56, 189, 248, 0.2);
  color: var(--color-text);
}

@media (max-width: 992px) {
  .navbar-nav {
    padding-top: 1rem;
    border-top: 1px solid rgba(148, 163, 184, 0.1);
  }

  .hero {
    padding-top: 6rem;
  }

  .hero-card {
    margin-top: 3rem;
  }

  .footer-social {
    justify-content: flex-start;
    margin-top: 1rem;
  }
}

@media (max-width: 768px) {
  .hero-cta {
    flex-direction: column;
    align-items: stretch;
  }

  .highlight-card {
    flex: 1 1 100%;
  }

  .timeline {
    padding-left: 0;
    border-left: none;
  }

  .timeline::before,
  .timeline-item::before {
    display: none;
  }

  .timeline-item {
    padding: 1.75rem;
  }

  .section {
    padding: 5rem 0;
  }

  .contact-card {
    margin-top: 2rem;
  }

  .footer-meta {
    flex-direction: column;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}