:root{
  --bg:#0f1115;        /* dark background */
  --panel:#181c24;     /* card background */
  --text:#e6edf3;      /* base text */
  --muted:#a0a7b4;     /* muted text */
  --brand:#f4b400;     /* amber title/menu */
  --link:#0ea5e9;      /* cyan links/buttons */
  --max:1100px;
  --radius:18px;
  --shadow:0 10px 30px rgba(0,0,0,.35);
  --header-h:72px;     /* used for spacing after hero */
}

*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;
  background:var(--bg);
  color:var(--text);
  font:16px/1.6 system-ui,-apple-system,Segoe UI,Roboto,Inter,Arial,sans-serif
}

/* Header / Nav (transparent over hero, solid after scroll) */
.header{
  position:fixed;      /* overlay hero */
  top:0; left:0; right:0;
  z-index:60;
  background:transparent;                      /* transparent at top */
  border-bottom:none;
  transition:background .25s ease, box-shadow .25s ease, padding .25s ease;
}
.nav{
  max-width:var(--max);
  margin:0 auto;
  padding:22px 24px;                            /* taller when transparent */
  display:flex;
  align-items:center;
  justify-content:space-between
}
.brand{
  font-weight:900;
  color:var(--brand);
  letter-spacing:.3px;
  font-size:1.15rem;
  text-shadow:0 2px 8px rgba(0,0,0,.35);
}
.menu{
  display:flex;
  gap:26px;
  align-items:center
}
.menu a{
  color:#fff;                                     /* white over photo */
  text-decoration:none;
  opacity:.95;
  font-weight:700;
  text-shadow:0 2px 8px rgba(0,0,0,.35);
}
.menu a:hover{opacity:1}
.btn-menu{
  display:none;
  padding:10px 14px;
  background:var(--brand);
  border:none;
  border-radius:12px;
  color:#111;
  font-weight:800
}

/* Solid compact header when scrolled */
.header.scrolled{
  background:rgba(15,17,21,.92);
  border-bottom:1px solid rgba(255,255,255,.06);
  backdrop-filter:blur(8px);
  box-shadow:0 8px 24px rgba(0,0,0,.25);
}
.header.scrolled .nav{ padding:14px 18px; }
.header.scrolled .menu a{
  color:var(--text);
  text-shadow:none;
  font-weight:600;
}
.header.scrolled .brand{ font-size:1rem; text-shadow:none; }

/* Drawer (mobile) */
.drawer{
  position:fixed;
  inset:0;
  background:rgba(0,0,0,.55);
  display:none;
  z-index:70
}
.drawer.open{display:block}
.drawer .panel{
  margin-left:auto;
  width:min(420px,90vw);
  height:100%;
  background:#121620;
  padding:22px 18px;
  border-left:1px solid rgba(255,255,255,.08);
  box-shadow:var(--shadow)
}
.drawer a{
  display:block;
  color:#e8edf6;
  text-decoration:none;
  font-weight:800;
  padding:16px 6px
}
.drawer a + a{
  border-top:1px dashed rgba(255,255,255,.08)
}

/* Hero (fills screen under the fixed header) */
.hero{
  position:relative;
  height:100vh;         /* fill the entire viewport */
  display:grid;
  place-items:center;
  padding:60px 18px;
  background:url('Images/Dallas.jpg') center/cover no-repeat;
}
.hero::after{
  content:"";
  position:absolute;
  inset:0;
  /* darker at top so white nav/text pop, subtle fade */
  background:linear-gradient(180deg, rgba(0,0,0,.70), rgba(0,0,0,.35) 45%, rgba(0,0,0,.60));
}
.hero-in{
  position:relative;
  z-index:1;
  max-width:var(--max);
  width:100%;
  display:grid;
  justify-items:center;
  text-align:center
}
.avatar{
  width:min(300px,60vw);
  aspect-ratio:1/1;
  border-radius:50%;
  object-fit:cover;
  border:12px solid rgba(255,255,255,.95);
  box-shadow:0 14px 42px rgba(0,0,0,.6)
}
.title{
  font-size:clamp(42px,8.5vw,96px);
  line-height:1.02;
  margin:22px 0 6px;
  font-weight:900;
  text-shadow:0 8px 28px rgba(0,0,0,.6);
}
.subtitle{
  font-size:clamp(18px,3.4vw,28px);
  opacity:.96;
  font-style:italic;
  text-shadow:0 6px 18px rgba(0,0,0,.55);
}
.cta{
  margin-top:26px;
  background:#e5e7eb;
  color:#111;
  padding:16px 24px;
  border-radius:16px;
  border:3px solid rgba(255,255,255,.35);
  font-weight:800;
  text-decoration:none
}

/* spacer AFTER hero so normal content begins below fixed header */
.content-start{ height:var(--header-h); }

/* Sections */
.section{
  max-width:var(--max);
  margin:0 auto;
  padding:84px 18px
}
.h2{
  font-weight:900;
  font-size:clamp(32px,5vw,52px);
  margin:0 0 16px
}
.lead{
  font-size:1.1rem;
  color:var(--muted);
  margin-bottom:26px
}

/* Blue panels (Skills-like) */
.panel-blue{
  background:#2f7fb0;
  color:#fff;
  border-radius:24px;
  padding:46px 22px;
  margin:26px 0
}
.panel-blue .big{
  font-size:clamp(28px,4.8vw,40px);
  font-weight:900;
  margin:0 0 10px
}
.panel-blue p{
  margin:8px 0 0;
  font-size:1.05rem
}
.icon-wrap{
  display:grid;
  place-items:center;
  margin:8px 0 18px
}
.icon-circle{
  width:124px;
  height:124px;
  border-radius:50%;
  display:grid;
  place-items:center;
  background:#e6f3fb;
  color:#f0b429;
  font-size:64px
}

/* Generic cards grid (Projects/Papers) */
.grid{
  display:grid;
  gap:20px
}
@media (min-width:800px){
  .grid{grid-template-columns:repeat(3,1fr)}
}
.card{
  background:var(--panel);
  padding:22px;
  border-radius:16px;
  border:1px solid rgba(255,255,255,.06);
  box-shadow:var(--shadow)
}
.card h3{margin:0 0 8px}

/* Timeline */
.timeline{
  border-left:3px solid rgba(255,255,255,.2);
  padding-left:18px
}
.item{margin:18px 0}
.item time{
  color:#9cc3ff;
  font-weight:700
}

/* Contact + footer cluster */
.contact-wrap{
  background:#0f1115;
  color:#fff
}
.contact-inner{
  max-width:800px;
  margin:0 auto;
  padding:60px 20px
}
.contact-inner h2{
  font-size:clamp(28px,4vw,48px);
  margin-bottom:12px
}
.contact-inner p{
  margin:6px 0;
  font-size:1.05rem
}
.contact-inner strong{
  color:var(--brand)
}
form{
  margin-top:26px;
  display:grid;
  gap:16px
}
input,textarea{
  width:100%;
  padding:12px 14px;
  border-radius:8px;
  border:1px solid rgba(255,255,255,.2);
  background:#1a1f29;
  color:#fff;
  font-size:1rem
}
textarea{
  min-height:140px;
  resize:vertical
}
button{
  background:var(--link);
  color:#fff;
  border:none;
  padding:14px 20px;
  font-size:1rem;
  border-radius:8px;
  font-weight:700;
  cursor:pointer
}
button:hover{opacity:.9}
.footer{
  margin-top:40px;
  text-align:center;
  color:var(--muted)
}
.socials{
  margin:16px 0;
  display:flex;
  gap:20px;
  justify-content:center
}
.socials a{
  display:flex;
  align-items:center;
  justify-content:center;
  width:58px;
  height:58px;
  border-radius:50%;
  background:var(--link);
  color:#fff;
  font-size:1.4rem;
  text-decoration:none;
  box-shadow:var(--shadow)
}
.footer-links{
  display:flex;
  gap:16px;
  justify-content:center;
  flex-wrap:wrap;
  margin-top:14px
}
.footer-links a{
  color:var(--brand);
  text-decoration:none;
  font-weight:800
}

/* Back to top */
.toTop{
  position:fixed;
  right:18px;
  bottom:18px;
  background:#222a35;
  color:#fff;
  border:none;
  border-radius:16px;
  padding:12px 14px;
  opacity:.85;
  display:none;
  z-index:80
}
.toTop.show{display:block}

/* Responsive tweaks */
@media (max-width:760px){
  .menu{display:none}
  .btn-menu{display:inline-flex;align-items:center;gap:8px}
}