/* ==========================================================================
   Nadeeshan Dissanayake — portfolio
   Dark, antigravity-inspired theme. No frameworks, no external requests.
   ========================================================================== */

@font-face {
  font-family: 'Space Grotesk';
  font-style: normal;
  font-weight: 300 700;
  font-display: swap;
  src: url('../fonts/space-grotesk-var-latin.woff2') format('woff2');
}
@font-face {
  font-family: 'Inter';
  font-style: normal;
  font-weight: 100 900;
  font-display: swap;
  src: url('../fonts/inter-var-latin.woff2') format('woff2');
}

:root {
  --bg: #07070f;
  --bg-elevated: rgba(255, 255, 255, 0.03);
  --border: rgba(255, 255, 255, 0.09);
  --border-bright: rgba(139, 148, 255, 0.35);
  --text: #e6e6f0;
  --text-dim: #9b9bb0;
  --accent-1: #6c8cff;   /* periwinkle blue */
  --accent-2: #b06cff;   /* violet */
  --accent-3: #4dd8ff;   /* cyan */
  --glow-1: rgba(108, 140, 255, 0.22);
  --glow-2: rgba(176, 108, 255, 0.16);
  --radius: 18px;
  --font-display: 'Space Grotesk', system-ui, sans-serif;
  --font-body: 'Inter', system-ui, -apple-system, sans-serif;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; scroll-padding-top: 84px; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.7;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

::selection { background: rgba(108, 140, 255, 0.4); }

a { color: var(--accent-1); text-decoration: none; transition: color 0.2s ease; }
a:hover { color: var(--accent-3); text-decoration: underline; text-underline-offset: 3px; }

/* ------------------------------ backdrop layers ------------------------ */

#starfield {
  position: fixed;
  inset: 0;
  z-index: -2;
  display: block;
}

#cursor-glow {
  position: fixed;
  top: 0;
  left: 0;
  width: 560px;
  height: 560px;
  margin: -280px 0 0 -280px;
  border-radius: 50%;
  background: radial-gradient(circle,
    rgba(108, 140, 255, 0.14) 0%,
    rgba(176, 108, 255, 0.08) 35%,
    transparent 70%);
  pointer-events: none;
  z-index: -1;
  opacity: 0;
  transition: opacity 0.6s ease;
}
body.has-cursor #cursor-glow { opacity: 1; }

/* ------------------------------ nav ------------------------------------ */

.site-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  gap: 1.5rem;
  padding: 0.8rem clamp(1rem, 4vw, 2.5rem);
  background: rgba(7, 7, 15, 0.72);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border);
}

.brand {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.15rem;
  color: var(--text);
  white-space: nowrap;
}
.brand:hover { text-decoration: none; color: var(--text); }
.brand-dot { color: var(--accent-2); }

.site-nav nav {
  display: flex;
  gap: 0.25rem;
  margin-left: auto;
  overflow-x: auto;
  scrollbar-width: none;
}
.site-nav nav::-webkit-scrollbar { display: none; }

.site-nav nav a {
  font-family: var(--font-display);
  font-size: 0.92rem;
  color: var(--text-dim);
  padding: 0.35rem 0.7rem;
  border-radius: 999px;
  white-space: nowrap;
}
.site-nav nav a:hover {
  color: var(--text);
  background: var(--bg-elevated);
  text-decoration: none;
}

/* ------------------------------ hero ----------------------------------- */

.hero {
  position: relative;
  min-height: 100svh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 7rem clamp(1.25rem, 6vw, 4rem) 4rem;
  overflow: hidden;
}

.hero-glow {
  position: absolute;
  border-radius: 50%;
  filter: blur(90px);
  pointer-events: none;
}
.hero-glow-a {
  width: 480px; height: 480px;
  background: var(--glow-1);
  top: -120px; right: -80px;
  animation: drift 14s ease-in-out infinite alternate;
}
.hero-glow-b {
  width: 420px; height: 420px;
  background: var(--glow-2);
  bottom: -140px; left: -100px;
  animation: drift 18s ease-in-out infinite alternate-reverse;
}
@keyframes drift {
  from { transform: translate(0, 0) scale(1); }
  to   { transform: translate(40px, 30px) scale(1.12); }
}

.hero-inner {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: clamp(2rem, 6vw, 5rem);
  flex-wrap: wrap;
  max-width: 1080px;
  margin: 0 auto;
}

.hero-text { max-width: 620px; }

.hero-eyebrow {
  font-family: var(--font-display);
  color: var(--accent-3);
  letter-spacing: 0.25em;
  text-transform: uppercase;
  font-size: 0.85rem;
  margin-bottom: 0.75rem;
}

.hero-name {
  font-family: var(--font-display);
  font-size: clamp(2.6rem, 7vw, 4.6rem);
  font-weight: 700;
  line-height: 1.05;
  letter-spacing: -0.02em;
  margin-bottom: 1.25rem;
  background: linear-gradient(100deg, #ffffff 10%, var(--accent-1) 55%, var(--accent-2) 95%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.hero-subtitle {
  font-size: 1.08rem;
  color: var(--text-dim);
  margin-bottom: 1.4rem;
}

.hero-interests { color: var(--text-dim); font-size: 0.95rem; }

.chip {
  display: inline-block;
  font-family: var(--font-display);
  font-size: 0.82rem;
  color: var(--text);
  border: 1px solid var(--border-bright);
  border-radius: 999px;
  padding: 0.14rem 0.65rem;
  margin: 0.18rem 0.08rem;
  background: rgba(108, 140, 255, 0.08);
}

.hero-photo {
  position: relative;
  flex-shrink: 0;
}
.hero-photo img {
  display: block;
  width: clamp(200px, 24vw, 280px);
  height: auto;
  border-radius: var(--radius);
  border: 1px solid var(--border);
}
.photo-ring {
  position: absolute;
  inset: -14px;
  border-radius: calc(var(--radius) + 14px);
  background: conic-gradient(from 180deg, var(--accent-1), var(--accent-2), var(--accent-3), var(--accent-1));
  filter: blur(26px);
  opacity: 0.45;
  z-index: -1;
}

.float { animation: float 7s ease-in-out infinite; }
@keyframes float {
  0%, 100% { transform: translateY(0); }
  50%      { transform: translateY(-14px); }
}

.social-links {
  display: flex;
  gap: 0.6rem;
  margin-top: 1.5rem;
}
.social-links a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  border: 1px solid var(--border);
  color: var(--text-dim);
  background: var(--bg-elevated);
  transition: color 0.2s ease, border-color 0.2s ease, transform 0.2s ease, box-shadow 0.2s ease;
}
.social-links a:hover {
  color: var(--text);
  border-color: var(--border-bright);
  transform: translateY(-3px);
  box-shadow: 0 6px 24px rgba(108, 140, 255, 0.25);
  text-decoration: none;
}

.scroll-hint {
  position: absolute;
  left: 50%;
  bottom: 1.6rem;
  transform: translateX(-50%);
  width: 26px;
  height: 42px;
  border: 1.5px solid var(--text-dim);
  border-radius: 999px;
}
.scroll-hint span {
  position: absolute;
  left: 50%;
  top: 8px;
  width: 4px;
  height: 8px;
  margin-left: -2px;
  border-radius: 2px;
  background: var(--accent-3);
  animation: scrollhint 1.8s ease-in-out infinite;
}
@keyframes scrollhint {
  0%   { transform: translateY(0); opacity: 1; }
  70%  { transform: translateY(14px); opacity: 0; }
  100% { transform: translateY(0); opacity: 0; }
}

/* ------------------------------ sections ------------------------------- */

.section {
  max-width: 900px;
  margin: 0 auto;
  padding: 4.5rem clamp(1.25rem, 5vw, 2rem);
}

.section-title {
  font-family: var(--font-display);
  font-size: clamp(1.7rem, 4vw, 2.4rem);
  font-weight: 700;
  letter-spacing: -0.01em;
  margin-bottom: 2rem;
  background: linear-gradient(100deg, #ffffff 20%, var(--accent-1) 80%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.section-title::after {
  content: '';
  display: block;
  width: 64px;
  height: 3px;
  margin-top: 0.6rem;
  border-radius: 2px;
  background: linear-gradient(90deg, var(--accent-1), var(--accent-2));
}

.card {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.6rem 1.8rem;
  margin-bottom: 1.2rem;
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  transition: border-color 0.25s ease, box-shadow 0.25s ease, transform 0.25s ease;
}
.card:hover {
  border-color: var(--border-bright);
  box-shadow: 0 10px 40px rgba(108, 140, 255, 0.12);
  transform: translateY(-2px);
}

.card h3 {
  font-family: var(--font-display);
  font-size: 1.12rem;
  font-weight: 600;
  line-height: 1.45;
  color: var(--text);
}

.card p { margin: 0.6rem 0; }
.card ul { margin: 0.6rem 0 0.2rem 1.2rem; }
.card ul ul { margin-top: 0.25rem; }
.card li { margin: 0.3rem 0; color: var(--text); }
.card li li { color: var(--text-dim); }
.card strong { color: #ffffff; }

.item-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
}

.date {
  font-family: var(--font-display);
  font-size: 0.88rem;
  font-weight: 400;
  color: var(--accent-3);
  white-space: nowrap;
}

.tag-link {
  font-family: var(--font-display);
  font-size: 0.88em;
  color: var(--accent-2);
  white-space: nowrap;
}

/* timeline rail for education */
.timeline { position: relative; }

/* publications */
.pub p { color: var(--text-dim); }
.pub li { color: var(--text-dim); }

/* projects */
.project-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 1.2rem;
}
.project.mini { margin-bottom: 0; display: flex; align-items: flex-start; }
.project.mini h3 { font-size: 1rem; font-weight: 500; }

.project.featured {
  border-color: var(--border-bright);
  background:
    radial-gradient(ellipse at top right, rgba(108, 140, 255, 0.09), transparent 55%),
    var(--bg-elevated);
}
.project.featured li { color: var(--text-dim); }
.project.featured li:first-child { color: var(--text); }

.video-embed {
  position: relative;
  margin: 1.4rem auto 0;
  max-width: 560px;
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--border);
  background: #000;
}
/* The LinkedIn embed renders the full post text above the video; its natural
   height is ~1276px at 560px wide and grows as the container narrows
   (~1517px at 325px). Size the iframe to fit so the video is visible without
   scrolling inside the frame; if LinkedIn's rendering ever changes, the
   iframe still scrolls internally and the fallback link remains below. */
.video-embed iframe {
  display: block;
  width: 100%;
  height: 1300px;
  border: 0;
}
@media (max-width: 600px) {
  .video-embed iframe { height: calc(1330px + (600px - 100vw) * 1.05); }
}
.video-fallback {
  font-size: 0.88rem;
  color: var(--text-dim);
  text-align: center;
  margin-top: 0.7rem;
}

/* courses */
.courses-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.2rem;
  margin-bottom: 1.2rem;
}
.courses-grid .card { margin-bottom: 0; }
.courses-grid p { color: var(--text-dim); font-size: 0.94rem; }
.online-courses li { color: var(--text-dim); font-size: 0.94rem; }

/* ------------------------------ footer --------------------------------- */

.site-footer {
  border-top: 1px solid var(--border);
  padding: 2.5rem 1.5rem 3rem;
  text-align: center;
  color: var(--text-dim);
  font-size: 0.9rem;
}
.site-footer .social-links { justify-content: center; margin: 0 0 1.2rem; }

/* ------------------------------ reveal on scroll ----------------------- */

.reveal {
  opacity: 0;
  transform: translateY(26px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}
/* if JS never runs, keep everything visible */
html:not(.js) .reveal { opacity: 1; transform: none; }

/* ------------------------------ motion & touch ------------------------- */

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .float, .hero-glow-a, .hero-glow-b, .scroll-hint span { animation: none; }
  .reveal { opacity: 1; transform: none; transition: none; }
  #cursor-glow { display: none; }
}

@media (hover: none), (pointer: coarse) {
  #cursor-glow { display: none; }
}

/* ------------------------------ small screens -------------------------- */

@media (max-width: 640px) {
  .hero { padding-top: 6rem; }
  .hero-inner { flex-direction: column-reverse; text-align: center; }
  .hero-interests, .social-links { justify-content: center; }
  .social-links { flex-wrap: wrap; }
  .item-head { flex-direction: column; gap: 0.15rem; }
  .card { padding: 1.2rem 1.3rem; }
}