/* ============================================
   CSS Variables — dark theme & design tokens
   ============================================ */
:root {
  --bg-primary: #0a0a0f;
  --bg-secondary: #12121a;
  --bg-card: #16161f;
  --bg-card-hover: #1c1c28;

  --text-primary: #f4f4f5;
  --text-secondary: #a1a1aa;
  --text-muted: #71717a;

  --accent-start: #6366f1;
  --accent-mid: #8b5cf6;
  --accent-end: #a855f7;

  --gradient: linear-gradient(135deg, var(--accent-start), var(--accent-mid), var(--accent-end));
  --gradient-soft: linear-gradient(135deg, rgba(99, 102, 241, 0.15), rgba(168, 85, 247, 0.1));

  --border: rgba(255, 255, 255, 0.08);
  --shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
  --shadow-glow: 0 0 40px rgba(99, 102, 241, 0.25);

  --font-body: "Inter", system-ui, sans-serif;
  --font-heading: "Space Grotesk", system-ui, sans-serif;

  --header-height: 4.5rem;
  --radius: 12px;
  --radius-lg: 20px;
  --transition: 0.3s ease;
}

/* ============================================
   Reset & base styles
   ============================================ */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--header-height);
}

body {
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.6;
  color: var(--text-primary);
  background-color: var(--bg-primary);
  overflow-x: hidden;
}

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

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

ul {
  list-style: none;
}

button,
input,
textarea {
  font: inherit;
  color: inherit;
}

/* ============================================
   Layout utilities
   ============================================ */
.container {
  width: 100%;
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 1.25rem;
}

.section {
  padding: 5rem 0;
}

.section--alt {
  background-color: var(--bg-secondary);
}

.section__title {
  font-family: var(--font-heading);
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 700;
  text-align: center;
  margin-bottom: 0.5rem;
  background: var(--gradient);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.section__subtitle {
  text-align: center;
  color: var(--text-secondary);
  margin-bottom: 2.5rem;
  font-size: 1rem;
}

/* ============================================
   Cards — reusable card component
   ============================================ */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  box-shadow: var(--shadow);
  transition: transform var(--transition), border-color var(--transition), box-shadow var(--transition);
}

.card:hover {
  transform: translateY(-4px);
  border-color: rgba(99, 102, 241, 0.35);
  box-shadow: var(--shadow), var(--shadow-glow);
}

/* ============================================
   Buttons — gradient & outline styles
   ============================================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.95rem;
  border: none;
  cursor: pointer;
  transition: transform var(--transition), box-shadow var(--transition), opacity var(--transition);
}

.btn--primary {
  background: var(--gradient);
  color: #fff;
  box-shadow: 0 4px 20px rgba(99, 102, 241, 0.4);
}

.btn--primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 28px rgba(139, 92, 246, 0.5);
}

.btn--outline {
  background: transparent;
  border: 2px solid transparent;
  background-image: linear-gradient(var(--bg-card), var(--bg-card)), var(--gradient);
  background-origin: border-box;
  background-clip: padding-box, border-box;
  color: var(--text-primary);
}

.btn--outline:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-glow);
}

.btn--full {
  width: 100%;
}

/* ============================================
   Header & navigation
   ============================================ */
.header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: var(--header-height);
  z-index: 1000;
  background: rgba(10, 10, 15, 0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color var(--transition), box-shadow var(--transition);
}

.header--scrolled {
  border-bottom-color: var(--border);
  box-shadow: var(--shadow);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.nav__logo {
  font-family: var(--font-heading);
  font-size: 1.5rem;
  font-weight: 700;
  background: var(--gradient);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.nav__menu {
  display: flex;
  gap: 1.75rem;
}

.nav__link {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
  position: relative;
  transition: color var(--transition);
}

.nav__link::after {
  content: "";
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--gradient);
  border-radius: 2px;
  transition: width var(--transition);
}

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

.nav__link:hover::after,
.nav__link.active::after {
  width: 100%;
}

/* Mobile menu toggle (hamburger) */
.nav__toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.25rem;
}

.nav__toggle-bar {
  width: 24px;
  height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition);
}

.nav__toggle.active .nav__toggle-bar:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav__toggle.active .nav__toggle-bar:nth-child(2) {
  opacity: 0;
}

.nav__toggle.active .nav__toggle-bar:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ============================================
   Hero section
   ============================================ */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding-top: var(--header-height);
  overflow: hidden;
}

.hero__bg {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 50% at 50% -20%, rgba(99, 102, 241, 0.25), transparent),
    radial-gradient(ellipse 60% 40% at 100% 50%, rgba(168, 85, 247, 0.12), transparent),
    radial-gradient(ellipse 50% 30% at 0% 80%, rgba(99, 102, 241, 0.1), transparent);
  pointer-events: none;
  animation: pulse-bg 8s ease-in-out infinite alternate;
}

@keyframes pulse-bg {
  0% { opacity: 0.8; }
  100% { opacity: 1; }
}

.hero__container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: center;
  position: relative;
  z-index: 1;
}

.hero__greeting {
  color: var(--accent-mid);
  font-weight: 600;
  font-size: 1rem;
  margin-bottom: 0.5rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.hero__name {
  font-family: var(--font-heading);
  font-size: clamp(2.25rem, 5vw, 3.5rem);
  font-weight: 700;
  line-height: 1.15;
  margin-bottom: 0.5rem;
}

.hero__role {
  font-size: clamp(1.1rem, 2.5vw, 1.35rem);
  color: var(--text-secondary);
  margin-bottom: 1rem;
}

.hero__tagline {
  color: var(--text-muted);
  max-width: 32rem;
  margin-bottom: 1.75rem;
}

.hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.hero__social {
  display: flex;
  gap: 1rem;
}

.social-link {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--text-secondary);
  transition: color var(--transition), border-color var(--transition), transform var(--transition), box-shadow var(--transition);
}

.social-link svg {
  width: 20px;
  height: 20px;
}

.social-link:hover {
  color: var(--text-primary);
  border-color: rgba(99, 102, 241, 0.5);
  transform: translateY(-3px);
  box-shadow: var(--shadow-glow);
}

.social-link--placeholder {
  opacity: 0.7;
  cursor: not-allowed;
}

.hero__image-wrapper {
  justify-self: center;
  width: min(320px, 80vw);
  line-height: 0;
}

.hero__image {
  width: 100%;
  height: auto;
  aspect-ratio: 1;
  object-fit: cover;
  border-radius: 50%;
  display: block;
}

/* ============================================
   About section
   ============================================ */
.about p {
  color: var(--text-secondary);
  margin-bottom: 1rem;
}

.about p:last-child {
  margin-bottom: 0;
}

/* ============================================
   Skills section
   ============================================ */
.skills__grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 1.25rem;
}

.skill-card {
  text-align: center;
  padding: 1.5rem 1rem;
}

.skill-card__icon {
  font-size: 2rem;
  display: block;
  margin-bottom: 0.75rem;
}

.skill-card__name {
  font-family: var(--font-heading);
  font-size: 1rem;
  font-weight: 600;
}

/* ============================================
   Projects section
   ============================================ */
.projects__grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
}

.project-card {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.project-card__badge {
  display: inline-block;
  align-self: flex-start;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 0.25rem 0.75rem;
  border-radius: 999px;
  background: var(--gradient-soft);
  color: var(--accent-mid);
  border: 1px solid rgba(139, 92, 246, 0.3);
}

.project-card__title {
  font-family: var(--font-heading);
  font-size: 1.2rem;
  font-weight: 600;
}

.project-card__desc {
  color: var(--text-secondary);
  font-size: 0.95rem;
  flex-grow: 1;
}

.project-card__tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 0.5rem;
}

.project-card__tags li {
  font-size: 0.8rem;
  padding: 0.25rem 0.65rem;
  border-radius: 6px;
  background: var(--bg-secondary);
  color: var(--text-muted);
  border: 1px solid var(--border);
}

/* ============================================
   Education section
   ============================================ */
.education__item {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 1.5rem;
  align-items: start;
}

.education__year {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 0.9rem;
  padding: 0.35rem 0.85rem;
  border-radius: 999px;
  background: var(--gradient);
  color: #fff;
  white-space: nowrap;
}

.education__content h3 {
  font-family: var(--font-heading);
  font-size: 1.15rem;
  margin-bottom: 0.35rem;
}

.education__institution {
  color: var(--accent-mid);
  font-weight: 500;
  margin-bottom: 0.5rem;
}

.education__content p:last-child {
  color: var(--text-secondary);
}

/* ============================================
   Contact section
   ============================================ */
.contact__text {
  color: var(--text-secondary);
  text-align: center;
  margin-bottom: 1.5rem;
}

.contact__email {
  margin-top: 1.25rem;
  text-align: center;
  color: var(--text-primary);
  font-weight: 500;
  font-size: 1rem;
}

.contact__portfolio {
  margin-top: 1.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
  text-align: center;
}

.contact__portfolio-label {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-bottom: 0.75rem;
}

.contact__portfolio-link {
  display: block;
  word-break: break-all;
  color: var(--accent-mid);
  font-size: 0.85rem;
  margin-bottom: 1rem;
  transition: color var(--transition);
}

.contact__portfolio-link:hover {
  color: var(--text-primary);
}

.contact__form {
  max-width: 480px;
  margin: 0 auto 1.5rem;
}

.form__group {
  margin-bottom: 1rem;
}

.form__group label {
  display: block;
  font-size: 0.875rem;
  font-weight: 500;
  margin-bottom: 0.35rem;
  color: var(--text-secondary);
}

.form__group input,
.form__group textarea {
  width: 100%;
  padding: 0.75rem 1rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: var(--bg-secondary);
  transition: border-color var(--transition), box-shadow var(--transition);
}

.form__group input:focus,
.form__group textarea:focus {
  outline: none;
  border-color: var(--accent-start);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

.form__group textarea {
  resize: vertical;
  min-height: 100px;
}

.contact__links {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  justify-content: center;
}

/* ============================================
   Footer
   ============================================ */
.footer {
  padding: 1.5rem 0;
  border-top: 1px solid var(--border);
  background: var(--bg-secondary);
}

.footer__inner {
  text-align: center;
  color: var(--text-muted);
  font-size: 0.9rem;
}

/* ============================================
   Scroll to top button
   ============================================ */
.scroll-top {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  border: none;
  background: var(--gradient);
  color: #fff;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-glow);
  opacity: 0;
  visibility: hidden;
  transform: translateY(12px);
  transition: opacity var(--transition), visibility var(--transition), transform var(--transition);
  z-index: 999;
}

.scroll-top svg {
  width: 22px;
  height: 22px;
}

.scroll-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.scroll-top:hover {
  transform: translateY(-4px);
}

/* ============================================
   CSS-only scroll animations
   ============================================ */
.animate-fade-up {
  opacity: 0;
  transform: translateY(24px);
  animation: fade-up 0.8s ease forwards;
}

.animate-delay-1 { animation-delay: 0.15s; }
.animate-delay-2 { animation-delay: 0.3s; }

@keyframes fade-up {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Stagger animation for elements in view (CSS animation on load) */
.section .card.animate-fade-up,
.section .skill-card.animate-fade-up,
.section .project-card.animate-fade-up {
  animation-duration: 0.7s;
}

/* ============================================
   Responsive — tablet & mobile
   ============================================ */
@media (max-width: 900px) {
  .hero__container {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .hero__tagline {
    margin-left: auto;
    margin-right: auto;
  }

  .hero__actions,
  .hero__social {
    justify-content: center;
  }

  .hero__image-wrapper {
    order: -1;
  }
}

@media (max-width: 768px) {
  .nav__toggle {
    display: flex;
  }

  .nav__menu {
    position: fixed;
    top: var(--header-height);
    left: 0;
    width: 100%;
    flex-direction: column;
    align-items: center;
    gap: 0;
    background: rgba(10, 10, 15, 0.98);
    backdrop-filter: blur(12px);
    padding: 1.5rem 0 2rem;
    border-bottom: 1px solid var(--border);
    transform: translateY(-120%);
    opacity: 0;
    visibility: hidden;
    transition: transform var(--transition), opacity var(--transition), visibility var(--transition);
  }

  .nav__menu.show {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }

  .nav__menu li {
    width: 100%;
    text-align: center;
  }

  .nav__link {
    display: block;
    padding: 0.85rem 1rem;
  }

  .section {
    padding: 3.5rem 0;
  }

  .education__item {
    grid-template-columns: 1fr;
    gap: 0.75rem;
  }

  .contact__links {
    flex-direction: column;
    align-items: stretch;
  }

  .contact__links .btn {
    width: 100%;
  }
}

@media (max-width: 480px) {
  .hero__actions {
    flex-direction: column;
  }

  .hero__actions .btn {
    width: 100%;
  }

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