/* ============================================================
   Usama Nadeem — Modern Portfolio 2025
   Dark theme · Violet-indigo accents · Glassmorphism · Animations
   ============================================================ */

/* ---------- Google Fonts ---------- */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800;900&family=JetBrains+Mono:wght@400;500&display=swap');

/* ---------- CSS Custom Properties ---------- */
:root {
  --bg-primary:    #08080f;
  --bg-secondary:  #0f0f1a;
  --bg-card:       rgba(255,255,255,0.04);
  --bg-card-hover: rgba(255,255,255,0.07);
  --border:        rgba(255,255,255,0.08);
  --border-accent: rgba(124,58,237,0.4);

  --accent:        #7c3aed;
  --accent-light:  #8b5cf6;
  --accent-glow:   rgba(124,58,237,0.3);
  --indigo:        #6366f1;
  --gradient:      linear-gradient(135deg, var(--accent), var(--indigo));
  --gradient-text: linear-gradient(135deg, #a78bfa, #818cf8);

  --text-primary:  #f1f5f9;
  --text-secondary:#94a3b8;
  --text-muted:    #64748b;

  --radius-sm:     8px;
  --radius-md:     14px;
  --radius-lg:     20px;
  --radius-xl:     28px;

  --shadow-glow:   0 0 60px rgba(124,58,237,0.15);
  --shadow-card:   0 4px 32px rgba(0,0,0,0.4);

  --font-sans:     'Inter', system-ui, sans-serif;
  --font-mono:     'JetBrains Mono', monospace;

  --nav-h:         68px;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-sans);
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.7;
  overflow-x: hidden;
}

img, video { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }

/* ---------- Scrollbar ---------- */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg-primary); }
::-webkit-scrollbar-thumb { background: var(--accent); border-radius: 99px; }

/* ============================================================
   NAVIGATION
   ============================================================ */
.nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
  height: var(--nav-h);
  display: flex; align-items: center; justify-content: space-between;
  padding: 0 clamp(1.5rem, 5vw, 4rem);
  background: rgba(8,8,15,0.7);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
  transition: background 0.3s;
}

.nav__logo {
  font-size: 1.2rem; font-weight: 700; letter-spacing: -0.03em;
  background: var(--gradient-text); -webkit-background-clip: text; -webkit-text-fill-color: transparent;
}

.nav__links {
  display: flex; gap: 2.5rem; list-style: none;
}

.nav__links a {
  font-size: 0.875rem; font-weight: 500; color: var(--text-secondary);
  position: relative; transition: color 0.2s;
}

.nav__links a::after {
  content: ''; position: absolute; bottom: -4px; left: 0; width: 0; height: 2px;
  background: var(--gradient); border-radius: 99px; transition: width 0.3s;
}

.nav__links a:hover { color: var(--text-primary); }
.nav__links a:hover::after { width: 100%; }

.nav__cta {
  padding: 0.5rem 1.25rem; border-radius: var(--radius-sm);
  background: var(--gradient); font-size: 0.875rem; font-weight: 600;
  color: #fff !important; -webkit-text-fill-color: #fff !important;
  transition: opacity 0.2s, transform 0.2s;
}
.nav__cta:hover { opacity: 0.9; transform: translateY(-1px); }
.nav__cta::after { display: none !important; }

/* Mobile hamburger */
.nav__hamburger {
  display: none; flex-direction: column; gap: 5px; cursor: pointer;
  background: none; border: none; padding: 4px;
}
.nav__hamburger span {
  display: block; width: 24px; height: 2px;
  background: var(--text-primary); border-radius: 99px; transition: 0.3s;
}

/* ============================================================
   HERO SECTION
   ============================================================ */
.hero {
  min-height: 100vh;
  display: flex; align-items: center;
  padding: calc(var(--nav-h) + 4rem) clamp(1.5rem, 8vw, 8rem) 6rem;
  position: relative; overflow: hidden;
}

/* animated gradient orbs */
.hero::before, .hero::after {
  content: '';
  position: absolute; border-radius: 50%;
  filter: blur(80px); pointer-events: none; animation: float 8s ease-in-out infinite;
}
.hero::before {
  width: 600px; height: 600px; top: -100px; left: -150px;
  background: radial-gradient(circle, rgba(124,58,237,0.18) 0%, transparent 70%);
}
.hero::after {
  width: 500px; height: 500px; bottom: -50px; right: -100px;
  background: radial-gradient(circle, rgba(99,102,241,0.15) 0%, transparent 70%);
  animation-delay: -4s;
}

@keyframes float {
  0%, 100% { transform: translateY(0) scale(1); }
  50%       { transform: translateY(-30px) scale(1.05); }
}

.hero__content { position: relative; z-index: 1; max-width: 800px; }

.hero__badge {
  display: inline-flex; align-items: center; gap: 0.5rem;
  padding: 0.375rem 1rem; border-radius: 99px;
  border: 1px solid var(--border-accent);
  background: rgba(124,58,237,0.08);
  font-size: 0.8rem; font-weight: 500; color: var(--accent-light);
  margin-bottom: 1.5rem; letter-spacing: 0.05em; text-transform: uppercase;
}
.hero__badge::before {
  content: ''; width: 6px; height: 6px; border-radius: 50%;
  background: var(--accent-light);
  animation: pulse 2s ease-in-out infinite;
}
@keyframes pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50%       { opacity: 0.4; transform: scale(0.8); }
}

.hero__title {
  font-size: clamp(3rem, 7vw, 5.5rem);
  font-weight: 900; line-height: 1.05;
  letter-spacing: -0.04em;
  margin-bottom: 1rem;
}

.hero__title .name {
  background: var(--gradient-text);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
}

.hero__typewriter {
  font-size: clamp(1.2rem, 3vw, 1.75rem);
  font-weight: 400; color: var(--text-secondary);
  margin-bottom: 1.75rem; min-height: 2.5rem;
  display: flex; align-items: center; gap: 0.5rem;
}

.hero__typewriter .prefix { color: var(--text-primary); font-weight: 500; }

.hero__cursor {
  display: inline-block; width: 3px; height: 1.2em;
  background: var(--accent); border-radius: 2px;
  animation: blink 0.9s step-end infinite;
}
@keyframes blink { 0%, 100% { opacity: 1; } 50% { opacity: 0; } }

.hero__desc {
  font-size: 1.05rem; color: var(--text-secondary);
  max-width: 580px; margin-bottom: 2.5rem; line-height: 1.75;
}

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

.btn {
  display: inline-flex; align-items: center; gap: 0.5rem;
  padding: 0.75rem 1.75rem; border-radius: var(--radius-sm);
  font-size: 0.9rem; font-weight: 600; transition: 0.2s; cursor: pointer;
  border: none;
}

.btn-primary {
  background: var(--gradient); color: #fff;
  box-shadow: 0 4px 24px var(--accent-glow);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 8px 32px var(--accent-glow); }

.btn-outline {
  background: transparent; color: var(--text-primary);
  border: 1px solid var(--border);
}
.btn-outline:hover {
  border-color: var(--accent); color: var(--accent-light);
  transform: translateY(-2px);
}

.hero__scroll {
  position: absolute; bottom: 2.5rem; left: 50%; transform: translateX(-50%);
  display: flex; flex-direction: column; align-items: center; gap: 0.5rem;
  color: var(--text-muted); font-size: 0.75rem; letter-spacing: 0.1em;
  animation: bounce 2.5s ease-in-out infinite;
}
.hero__scroll svg { opacity: 0.5; }
@keyframes bounce {
  0%, 100% { transform: translateX(-50%) translateY(0); }
  50%       { transform: translateX(-50%) translateY(8px); }
}

/* ============================================================
   SECTIONS COMMON
   ============================================================ */
.section {
  padding: 7rem clamp(1.5rem, 8vw, 8rem);
}

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

.section__header {
  text-align: center; margin-bottom: 4rem;
}

.section__eyebrow {
  display: inline-block; font-size: 0.75rem; font-weight: 600;
  letter-spacing: 0.15em; text-transform: uppercase;
  color: var(--accent-light); margin-bottom: 0.75rem;
}

.section__title {
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 800; letter-spacing: -0.03em;
  line-height: 1.1;
}

.section__subtitle {
  margin-top: 0.75rem; font-size: 1rem;
  color: var(--text-secondary); max-width: 520px; margin-inline: auto;
}

/* Reveal animations */
.reveal {
  opacity: 0; transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
.reveal.visible { opacity: 1; transform: none; }

/* ============================================================
   SKILLS SECTION
   ============================================================ */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  align-items: start;
}

.about__bio h3 {
  font-size: 1.4rem; font-weight: 700; margin-bottom: 1rem;
  background: var(--gradient-text);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
}

.about__bio p {
  color: var(--text-secondary); line-height: 1.8; margin-bottom: 1rem;
}

.about__stat-row {
  display: flex; gap: 1.5rem; margin-top: 1.5rem; flex-wrap: wrap;
}

.about__stat {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 1rem 1.25rem;
  text-align: center;
}
.about__stat .num {
  font-size: 1.75rem; font-weight: 800;
  background: var(--gradient-text); -webkit-background-clip: text; -webkit-text-fill-color: transparent;
}
.about__stat .lbl { font-size: 0.75rem; color: var(--text-muted); margin-top: 0.2rem; }

.skills__groups { display: flex; flex-direction: column; gap: 1.5rem; }

.skill-group h4 {
  font-size: 0.75rem; font-weight: 600; letter-spacing: 0.12em;
  text-transform: uppercase; color: var(--text-muted); margin-bottom: 0.6rem;
}

.skill-tags { display: flex; flex-wrap: wrap; gap: 0.5rem; }

.tag {
  padding: 0.35rem 0.85rem; border-radius: 99px;
  background: rgba(124,58,237,0.1);
  border: 1px solid rgba(124,58,237,0.2);
  font-size: 0.8rem; font-weight: 500;
  color: var(--accent-light);
  font-family: var(--font-mono);
  transition: 0.2s;
}
.tag:hover {
  background: rgba(124,58,237,0.2); border-color: var(--accent);
  transform: translateY(-1px);
}

/* ============================================================
   EXPERIENCE TIMELINE
   ============================================================ */
.timeline {
  position: relative;
  max-width: 820px; margin: 0 auto;
}

.timeline::before {
  content: '';
  position: absolute; left: 20px; top: 0; bottom: 0; width: 2px;
  background: linear-gradient(to bottom, var(--accent), transparent);
  border-radius: 99px;
}

.timeline__item {
  position: relative; padding-left: 64px; margin-bottom: 3rem;
}

.timeline__dot {
  position: absolute; left: 9px; top: 24px;
  width: 24px; height: 24px; border-radius: 50%;
  background: var(--gradient); border: 3px solid var(--bg-primary);
  box-shadow: 0 0 0 3px var(--accent-glow);
  transition: transform 0.3s;
}
.timeline__item:hover .timeline__dot { transform: scale(1.3); }

.timeline__card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.75rem 2rem;
  transition: 0.25s;
  backdrop-filter: blur(8px);
}
.timeline__item:hover .timeline__card {
  border-color: var(--border-accent);
  background: var(--bg-card-hover);
  box-shadow: var(--shadow-glow);
  transform: translateX(4px);
}

.timeline__header {
  display: flex; justify-content: space-between; align-items: flex-start;
  gap: 1rem; margin-bottom: 0.4rem; flex-wrap: wrap;
}

.timeline__company {
  font-size: 1.1rem; font-weight: 700;
  background: var(--gradient-text);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
}
.timeline__role { font-size: 0.95rem; color: var(--text-primary); font-weight: 500; margin-bottom: 0.25rem; }
.timeline__period {
  font-size: 0.78rem; color: var(--text-muted);
  font-family: var(--font-mono);
  background: rgba(255,255,255,0.04);
  border: 1px solid var(--border);
  padding: 0.25rem 0.65rem; border-radius: 99px;
  white-space: nowrap;
}

.timeline__badge {
  font-size: 0.7rem; font-weight: 600; letter-spacing: 0.08em;
  text-transform: uppercase; color: var(--accent-light);
  background: rgba(124,58,237,0.12);
  border: 1px solid rgba(124,58,237,0.25);
  padding: 0.2rem 0.7rem; border-radius: 99px;
  margin-bottom: 0.75rem; display: inline-block;
}

.timeline__bullets {
  list-style: none; padding: 0; margin-top: 0.75rem;
  display: flex; flex-direction: column; gap: 0.5rem;
}
.timeline__bullets li {
  font-size: 0.875rem; color: var(--text-secondary);
  padding-left: 1.25rem; position: relative; line-height: 1.6;
}
.timeline__bullets li::before {
  content: '▸'; position: absolute; left: 0; color: var(--accent-light); font-size: 0.7rem; top: 3px;
}

/* ============================================================
   PROJECTS
   ============================================================ */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 1.75rem;
}

.project-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  display: flex; flex-direction: column;
  transition: 0.25s;
  backdrop-filter: blur(8px);
}

.project-card:hover {
  border-color: var(--border-accent);
  background: var(--bg-card-hover);
  box-shadow: var(--shadow-glow);
  transform: translateY(-4px);
}

.project-card__media {
  width: 100%; height: 180px; overflow: hidden;
  background: linear-gradient(135deg, rgba(124,58,237,0.15), rgba(99,102,241,0.1));
  display: flex; align-items: center; justify-content: center;
}

.project-card__media img,
.project-card__media video {
  width: 100%; height: 100%; object-fit: cover;
}

.project-card__icon {
  font-size: 3rem; opacity: 0.6;
}

.project-card__body { padding: 1.5rem; flex: 1; display: flex; flex-direction: column; gap: 0.75rem; }

.project-card__title {
  font-size: 1.1rem; font-weight: 700; color: var(--text-primary);
}

.project-card__desc { font-size: 0.875rem; color: var(--text-secondary); line-height: 1.65; flex: 1; }

.project-card__tags { display: flex; flex-wrap: wrap; gap: 0.4rem; }

.project-card__tag {
  font-size: 0.72rem; font-family: var(--font-mono);
  padding: 0.2rem 0.6rem; border-radius: 99px;
  background: rgba(255,255,255,0.05); border: 1px solid var(--border);
  color: var(--text-muted);
}

.project-card__actions {
  display: flex; gap: 0.75rem; margin-top: 0.25rem;
}

.project-card__link {
  display: inline-flex; align-items: center; gap: 0.35rem;
  font-size: 0.82rem; font-weight: 600; color: var(--accent-light);
  border: 1px solid rgba(124,58,237,0.25);
  padding: 0.4rem 0.9rem; border-radius: var(--radius-sm);
  transition: 0.2s; background: rgba(124,58,237,0.08);
}
.project-card__link:hover {
  background: rgba(124,58,237,0.18); border-color: var(--accent);
  transform: translateY(-1px);
}

/* ============================================================
   EDUCATION & PUBLICATION
   ============================================================ */
.edu-pub-grid {
  display: grid; grid-template-columns: 1fr 1fr; gap: 1.75rem;
  max-width: 900px; margin: 0 auto;
}

.edu-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 1.75rem;
  display: flex; flex-direction: column; gap: 0.5rem;
  transition: 0.25s;
}
.edu-card:hover { border-color: var(--border-accent); background: var(--bg-card-hover); }

.edu-card__icon {
  font-size: 2rem; margin-bottom: 0.25rem;
}

.edu-card__school {
  font-size: 1rem; font-weight: 700;
  background: var(--gradient-text); -webkit-background-clip: text; -webkit-text-fill-color: transparent;
}

.edu-card__degree { font-size: 0.9rem; color: var(--text-primary); font-weight: 500; }
.edu-card__detail { font-size: 0.82rem; color: var(--text-muted); font-family: var(--font-mono); }

.pub-card {
  background: var(--bg-card);
  border: 1px solid var(--border-accent);
  border-radius: var(--radius-lg); padding: 1.75rem;
  grid-column: 1 / -1;
  transition: 0.25s;
  position: relative; overflow: hidden;
}
.pub-card::before {
  content: '';
  position: absolute; top: 0; left: 0; right: 0; height: 2px;
  background: var(--gradient);
}
.pub-card:hover { border-color: var(--accent); background: var(--bg-card-hover); }

.pub-card__label {
  font-size: 0.7rem; font-weight: 600; letter-spacing: 0.12em;
  text-transform: uppercase; color: var(--accent-light);
  margin-bottom: 0.5rem; display: block;
}

.pub-card__title {
  font-size: 1.1rem; font-weight: 700; margin-bottom: 0.5rem;
}

.pub-card__desc { font-size: 0.875rem; color: var(--text-secondary); line-height: 1.65; margin-bottom: 1rem; }

/* ============================================================
   FOOTER
   ============================================================ */
.footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border);
  padding: 4rem clamp(1.5rem, 8vw, 8rem) 3rem;
  text-align: center;
  display: flex; flex-direction: column; align-items: center; gap: 1.5rem;
}

.footer__name {
  font-size: 1.5rem; font-weight: 800; letter-spacing: -0.03em;
  background: var(--gradient-text);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
}

.footer__tagline { font-size: 0.875rem; color: var(--text-muted); }

.footer__links {
  display: flex; gap: 1.25rem; flex-wrap: wrap; justify-content: center;
}

.footer__link {
  display: inline-flex; align-items: center; gap: 0.4rem;
  padding: 0.5rem 1.1rem; border-radius: var(--radius-sm);
  background: var(--bg-card); border: 1px solid var(--border);
  font-size: 0.85rem; font-weight: 500; color: var(--text-secondary);
  transition: 0.2s;
}
.footer__link:hover { border-color: var(--accent-light); color: var(--text-primary); transform: translateY(-2px); }

.footer__copy { font-size: 0.75rem; color: var(--text-muted); margin-top: 1rem; }

/* ============================================================
   RESPONSIVE
   ============================================================ */
@media (max-width: 900px) {
  .about-grid { grid-template-columns: 1fr; gap: 3rem; }
  .edu-pub-grid { grid-template-columns: 1fr; }
  .pub-card { grid-column: 1; }
}

@media (max-width: 768px) {
  .nav__links { display: none; }
  .nav__hamburger { display: flex; }
  .nav__links.open {
    display: flex; flex-direction: column;
    position: fixed; top: var(--nav-h); left: 0; right: 0;
    background: rgba(8,8,15,0.98); backdrop-filter: blur(16px);
    padding: 2rem; gap: 1.5rem;
    border-bottom: 1px solid var(--border);
  }
  .timeline::before { left: 12px; }
  .timeline__item { padding-left: 44px; }
  .timeline__dot { left: 2px; width: 20px; height: 20px; }
  .section { padding: 5rem 1.5rem; }
  .hero { padding: calc(var(--nav-h) + 3rem) 1.5rem 4rem; }
}

@media (max-width: 480px) {
  .projects-grid { grid-template-columns: 1fr; }
  .hero__title { font-size: 2.5rem; }
  .hero__actions { flex-direction: column; }
  .btn { width: 100%; justify-content: center; }
  .about__stat-row { justify-content: center; }
}