/* ===========================
   CSS Variables & Design Tokens
   =========================== */
:root {
  --gradient-start: #6C63FF;
  --gradient-end: #FF6584;
  --accent: #00D4AA;
  --dark-bg: #0F0F1A;
  --alt-bg: #1A1A2E;
  --card-surface: #16213E;
  --text-primary: #FFFFFF;
  --text-secondary: #B0B0C8;
  --font-heading: 'Space Grotesk', sans-serif;
  --font-body: 'Inter', sans-serif;
  --transition: 0.3s ease;
}

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

html {
  scroll-behavior: smooth;
}

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

body.modal-open {
  overflow: hidden;
}

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

ul {
  list-style: none;
}

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

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

.section-title {
  font-family: var(--font-heading);
  font-size: 2.2rem;
  text-align: center;
  margin-bottom: 3rem;
  background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* ===========================
   Skip Link
   =========================== */
.skip-link {
  position: absolute;
  top: -100%;
  left: 1rem;
  background: var(--gradient-start);
  color: var(--text-primary);
  padding: 0.75rem 1.5rem;
  border-radius: 0 0 0.5rem 0.5rem;
  z-index: 1000;
  font-weight: 600;
  transition: top var(--transition);
}

.skip-link:focus {
  top: 0;
}

/* ===========================
   Navbar
   =========================== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  padding: 1rem 0;
  transition: background var(--transition), box-shadow var(--transition);
}

.navbar.scrolled {
  background: rgba(15, 15, 26, 0.95);
  backdrop-filter: blur(10px);
  box-shadow: 0 2px 20px rgba(0, 0, 0, 0.3);
}

.nav-container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  font-family: var(--font-heading);
  font-size: 1.8rem;
  font-weight: 700;
  background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 2rem;
}

.nav-links a {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: color var(--transition);
  position: relative;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
  transition: width var(--transition);
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--text-primary);
}

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

.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
  z-index: 110;
}

.hamburger span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--text-primary);
  transition: transform var(--transition), opacity var(--transition);
}

.hamburger.active span:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

.hamburger.active span:nth-child(2) {
  opacity: 0;
}

.hamburger.active span:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

/* ===========================
   Hero
   =========================== */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
  background-size: 200% 200%;
  animation: gradientShift 8s ease infinite;
  position: relative;
}

@keyframes gradientShift {
  0% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

.hero-content {
  padding: 2rem;
}

.hero-title {
  font-family: var(--font-heading);
  font-size: 6rem;
  font-weight: 700;
  letter-spacing: -2px;
  margin-bottom: 0.5rem;
}

.hero-subtitle {
  font-size: 1.4rem;
  font-weight: 400;
  opacity: 0.9;
  margin-bottom: 2.5rem;
}

.btn-primary {
  display: inline-block;
  padding: 0.9rem 2.5rem;
  background: rgba(255, 255, 255, 0.15);
  border: 2px solid rgba(255, 255, 255, 0.4);
  border-radius: 50px;
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: background var(--transition), transform var(--transition);
}

.btn-primary:hover {
  background: rgba(255, 255, 255, 0.25);
  transform: translateY(-2px);
}

.btn-primary:focus-visible {
  outline: 3px solid var(--text-primary);
  outline-offset: 3px;
}

/* ===========================
   About
   =========================== */
.about {
  background: var(--dark-bg);
  padding: 6rem 0;
}

.about-grid {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 3rem;
}

.about-image {
  flex-shrink: 0;
}

.about-portrait {
  width: 250px;
  height: 250px;
  border-radius: 50%;
  object-fit: cover;
  object-position: top;
  border: 3px solid transparent;
  background: linear-gradient(var(--dark-bg), var(--dark-bg)) padding-box,
              linear-gradient(135deg, var(--gradient-start), var(--gradient-end)) border-box;
}

.about-text p {
  color: var(--text-secondary);
  margin-bottom: 1rem;
  font-size: 1.05rem;
}

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

/* ===========================
   Portfolio
   =========================== */
.portfolio {
  background: var(--dark-bg);
  padding: 6rem 0;
}

.filter-buttons {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.75rem;
  margin-bottom: 2.5rem;
}

.filter-btn {
  padding: 0.5rem 1.5rem;
  background: transparent;
  border: 1px solid rgba(255, 255, 255, 0.15);
  border-radius: 50px;
  color: var(--text-secondary);
  font-family: var(--font-body);
  font-size: 0.9rem;
  cursor: pointer;
  transition: all var(--transition);
}

.filter-btn:hover {
  border-color: var(--gradient-start);
  color: var(--text-primary);
}

.filter-btn.active {
  background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
  border-color: transparent;
  color: var(--text-primary);
}

.filter-btn:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 3px;
}

.portfolio-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}

.portfolio-card {
  position: relative;
  border-radius: 12px;
  overflow: hidden;
  cursor: pointer;
  height: 240px;
  transition: transform var(--transition), box-shadow var(--transition);
}

.portfolio-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 30px rgba(108, 99, 255, 0.2);
}

.portfolio-card:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 3px;
}

.portfolio-card.hidden {
  display: none;
}

.card-bg {
  position: absolute;
  inset: 0;
  transition: transform var(--transition);
}

.portfolio-card:hover .card-bg {
  transform: scale(1.05);
}

.card-bg-1 { background: linear-gradient(135deg, #6C63FF, #3F3D99); }
.card-bg-2 { background: linear-gradient(135deg, #FF6584, #C44569); }
.card-bg-3 { background: linear-gradient(135deg, #00D4AA, #0A8F6E); }
.card-bg-4 { background: linear-gradient(135deg, #FFD93D, #E6A800); }
.card-bg-5 { background: linear-gradient(135deg, #6C63FF, #FF6584); }
.card-bg-6 { background: linear-gradient(135deg, #3498DB, #2C3E50); }
.card-bg-7 { background: linear-gradient(135deg, #E74C3C, #8E44AD); }

.card-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(to top, rgba(0, 0, 0, 0.7), transparent);
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  padding: 1.5rem;
}

.card-overlay h3 {
  font-family: var(--font-heading);
  font-size: 1.3rem;
  margin-bottom: 0.5rem;
}

.card-tag {
  display: inline-block;
  padding: 0.25rem 0.75rem;
  background: rgba(255, 255, 255, 0.15);
  border-radius: 50px;
  font-size: 0.8rem;
  width: fit-content;
}

/* ===========================
   Modal
   =========================== */
.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.7);
  backdrop-filter: blur(5px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 200;
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition), visibility var(--transition);
  padding: 1.5rem;
}

.modal-backdrop.active {
  opacity: 1;
  visibility: visible;
}

.modal {
  background: var(--card-surface);
  border-radius: 16px;
  padding: 2.5rem;
  max-width: 550px;
  width: 100%;
  position: relative;
  transform: translateY(20px);
  transition: transform var(--transition);
}

.modal-backdrop.active .modal {
  transform: translateY(0);
}

.modal-close {
  position: absolute;
  top: 1rem;
  right: 1.25rem;
  background: none;
  border: none;
  color: var(--text-secondary);
  font-size: 1.8rem;
  cursor: pointer;
  line-height: 1;
  transition: color var(--transition);
}

.modal-close:hover {
  color: var(--text-primary);
}

.modal-close:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 3px;
}

.modal-title {
  font-family: var(--font-heading);
  font-size: 1.5rem;
  margin-bottom: 1rem;
  padding-right: 2rem;
  background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.modal-description {
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ===========================
   Experience / Timeline
   =========================== */
.experience {
  background: var(--alt-bg);
  padding: 6rem 0;
}

.timeline {
  position: relative;
  max-width: 800px;
  margin: 0 auto;
  padding-left: 2rem;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 3px;
  background: linear-gradient(to bottom, var(--gradient-start), var(--gradient-end));
  border-radius: 3px;
}

.timeline-item {
  position: relative;
  padding-bottom: 2.5rem;
  padding-left: 2rem;
}

.timeline-item::before {
  content: '';
  position: absolute;
  left: -2rem;
  top: 0.25rem;
  width: 13px;
  height: 13px;
  background: var(--gradient-start);
  border: 3px solid var(--alt-bg);
  border-radius: 50%;
  transform: translateX(-5px);
}

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

.timeline-content {
  background: var(--card-surface);
  padding: 1.5rem;
  border-radius: 10px;
  transition: transform var(--transition), box-shadow var(--transition);
}

.timeline-content:hover {
  transform: translateY(-2px);
  box-shadow: 0 5px 20px rgba(0, 0, 0, 0.2);
}

.timeline-date {
  display: inline-block;
  padding: 0.25rem 0.75rem;
  background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
  border-radius: 50px;
  font-size: 0.8rem;
  font-weight: 600;
  margin-bottom: 0.75rem;
}

.timeline-content h3 {
  font-family: var(--font-heading);
  font-size: 1.2rem;
  margin-bottom: 0.25rem;
}

.timeline-content h4 {
  color: var(--accent);
  font-size: 0.95rem;
  font-weight: 500;
  margin-bottom: 0.75rem;
}

.timeline-content p {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

/* Fade-in animation */
.fade-in {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ===========================
   Contact
   =========================== */
.contact {
  background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
  padding: 6rem 0;
}

.contact .section-title {
  -webkit-text-fill-color: var(--text-primary);
  background: none;
}

.contact-grid {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1.5rem;
}

.contact-item {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1rem 2rem;
  background: rgba(255, 255, 255, 0.1);
  border-radius: 12px;
  transition: background var(--transition), transform var(--transition);
  font-weight: 500;
}

a.contact-item:hover {
  background: rgba(255, 255, 255, 0.2);
  transform: translateY(-2px);
}

a.contact-item:focus-visible {
  outline: 3px solid var(--text-primary);
  outline-offset: 3px;
}

/* ===========================
   Footer
   =========================== */
.footer {
  background: #0A0A14;
  padding: 2rem 0;
  text-align: center;
}

.footer p {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

/* ===========================
   Responsive — 768px+
   =========================== */
@media (min-width: 768px) {
  .about-grid {
    flex-direction: row;
    align-items: flex-start;
  }

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

  .contact-grid {
    flex-direction: row;
    justify-content: center;
  }
}

/* ===========================
   Responsive — 1024px+
   =========================== */
@media (min-width: 1024px) {
  .hamburger {
    display: none !important;
  }

  .nav-links {
    display: flex !important;
  }

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

  /* Alternating timeline */
  .timeline {
    padding-left: 0;
  }

  .timeline::before {
    left: 50%;
    transform: translateX(-50%);
  }

  .timeline-item {
    width: 50%;
    padding-left: 2.5rem;
  }

  .timeline-item:nth-child(odd) {
    margin-left: 0;
    padding-left: 0;
    padding-right: 2.5rem;
    text-align: right;
  }

  .timeline-item:nth-child(even) {
    margin-left: 50%;
  }

  .timeline-item::before {
    left: auto;
  }

  .timeline-item:nth-child(odd)::before {
    right: -2.5rem;
    left: auto;
    transform: translateX(5px);
  }

  .timeline-item:nth-child(even)::before {
    left: -2.5rem;
    transform: translateX(-5px);
  }
}

/* ===========================
   Mobile Nav (< 1024px)
   =========================== */
@media (max-width: 1023px) {
  .hamburger {
    display: flex;
  }

  .nav-links {
    display: none;
    position: fixed;
    top: 0;
    right: 0;
    width: 280px;
    height: 100vh;
    background: rgba(15, 15, 26, 0.98);
    backdrop-filter: blur(15px);
    flex-direction: column;
    padding: 5rem 2rem 2rem;
    gap: 1.5rem;
    box-shadow: -5px 0 30px rgba(0, 0, 0, 0.3);
  }

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

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

/* ===========================
   Focus Visible
   =========================== */
*:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 2px;
}

*:focus:not(:focus-visible) {
  outline: none;
}

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

  html {
    scroll-behavior: auto;
  }

  .fade-in {
    opacity: 1;
    transform: none;
    transition: none;
  }
}