/* ============================================================
   Yuriy Sinchuk — personal portfolio
   futuristic IT / AI / techno-space aesthetic
   palette: green primary, turquoise/blue secondary, VSCode-ish bg
   ============================================================ */

:root {
  /* ---------- DARK theme (default) ---------- */
  --bg-0: #232830;
  --bg-1: #2a2f38;
  --bg-2: #313742;
  --panel: rgba(48, 55, 66, 0.55);
  --panel-border: rgba(124, 242, 138, 0.18);
  --panel-border-hover: rgba(124, 242, 138, 0.5);

  --fg: #e2e8ef;
  --fg-dim: #a4b0c0;
  --fg-faint: #7c8898;

  /* primary highlight = green */
  --accent:    #7cf28a;
  /* secondary = turquoise / blue */
  --accent-2:  #6ad1ff;
  --accent-3:  #56c8e8;

  /* coloured tints for chips / glows */
  --accent-tint:    rgba(124, 242, 138, 0.10);
  --accent-tint-2:  rgba(124, 242, 138, 0.20);
  --accent-2-tint:  rgba(106, 209, 255, 0.08);
  --accent-2-tint-2:rgba(106, 209, 255, 0.30);

  --hero-grad-from: #ffffff;
  --header-bg:      rgba(35, 40, 48, 0.75);
  --grid-line:      rgba(124, 242, 138, 0.035);
  --bg-glow-1:      rgba(124, 242, 138, 0.10);
  --bg-glow-2:      rgba(106, 209, 255, 0.07);
  --bg-glow-3:      rgba(86, 200, 232, 0.05);
  --bg-gradient:    linear-gradient(180deg, #262b34 0%, #232830 45%, #1f242c 100%);

  --link-hover: #b4e4ff;

  --warn: #ffb86b;

  --mono: 'JetBrains Mono', 'SFMono-Regular', Consolas, ui-monospace, monospace;
  --sans: 'Space Grotesk', system-ui, -apple-system, Segoe UI, sans-serif;

  --max-w: 880px;
}

/* ---------- LIGHT theme — claude.ai cream ---------- */
:root[data-theme="light"] {
  --bg-0: #faf9f5;
  --bg-1: #f3f1ea;
  --bg-2: #ecebe4;
  --panel: rgba(255, 255, 255, 0.7);
  --panel-border: rgba(31, 35, 40, 0.10);
  --panel-border-hover: rgba(31, 35, 40, 0.28);

  --fg: #1f2328;
  --fg-dim: #4d5566;
  --fg-faint: #6e7889;

  /* darker, AA-friendly variants */
  --accent:    #1f8a3a;   /* primary green */
  --accent-2:  #0d6dbc;   /* secondary blue */
  --accent-3:  #1565c0;

  --accent-tint:    rgba(31, 138, 58, 0.08);
  --accent-tint-2:  rgba(31, 138, 58, 0.22);
  --accent-2-tint:  rgba(13, 109, 188, 0.07);
  --accent-2-tint-2:rgba(13, 109, 188, 0.28);

  --hero-grad-from: #1f2328;
  --header-bg:      rgba(250, 249, 245, 0.82);
  --grid-line:      rgba(31, 35, 40, 0.045);
  --bg-glow-1:      rgba(31, 138, 58, 0.06);
  --bg-glow-2:      rgba(13, 109, 188, 0.05);
  --bg-glow-3:      rgba(21, 101, 192, 0.04);
  --bg-gradient:    linear-gradient(180deg, #faf9f5 0%, #f7f5ee 50%, #f3f1ea 100%);

  --link-hover: #0a5a9c;
}

/* hide the starfield in light mode — it has no place in daylight */
:root[data-theme="light"] #starfield { display: none; }

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg-0);
  color: var(--fg);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  scroll-behavior: smooth;
}

/* layered background — themed via variables */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  background:
    radial-gradient(1100px 700px at 80% -10%, var(--bg-glow-1), transparent 60%),
    radial-gradient(900px 600px at -10% 30%,  var(--bg-glow-2), transparent 65%),
    radial-gradient(800px 800px at 50% 110%, var(--bg-glow-3), transparent 70%),
    var(--bg-gradient);
  z-index: -2;
  transition: background .35s ease;
}

#starfield {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  z-index: -1;
  display: block;
  pointer-events: none;
}

/* subtle grid overlay (themed) */
body::after {
  content: "";
  position: fixed;
  inset: 0;
  background-image:
    linear-gradient(var(--grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
  background-size: 60px 60px;
  z-index: -1;
  pointer-events: none;
  mask-image: radial-gradient(circle at 50% 30%, black 30%, transparent 90%);
  -webkit-mask-image: radial-gradient(circle at 50% 30%, black 30%, transparent 90%);
}

.container {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 1.5rem;
}

a {
  color: var(--accent-2);
  text-decoration: none;
  border-bottom: 1px dashed transparent;
  transition: border-color .2s, color .2s;
}

a:hover {
  color: var(--link-hover);
  border-bottom-color: var(--accent-2);
}

/* ============================================================
   HEADER / NAV
   ============================================================ */

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  background: var(--header-bg);
  border-bottom: 1px solid var(--panel-border);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 1rem;
  padding-bottom: 1rem;
  flex-wrap: wrap;
  gap: .75rem;
}

.brand {
  font-family: var(--mono);
  font-size: .95rem;
  color: var(--fg-dim);
  letter-spacing: .02em;
}
.brand-prefix { color: var(--accent); }
.brand-name   { color: var(--fg); }
.cursor {
  display: inline-block;
  color: var(--accent);
  animation: blink 1.1s steps(2) infinite;
}
@keyframes blink { 50% { opacity: 0; } }

.site-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 1.1rem;
  font-family: var(--mono);
  font-size: .85rem;
}
.site-nav a {
  color: var(--fg-dim);
  border-bottom: none;
  position: relative;
}
.site-nav a::before {
  content: "/";
  color: var(--fg-faint);
  margin-right: .25rem;
}
.site-nav a:hover {
  color: var(--accent);
}

/* ----- theme toggle button ----- */
.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  padding: 0;
  margin-left: .25rem;
  background: var(--panel);
  color: var(--fg-dim);
  border: 1px solid var(--panel-border);
  border-radius: 8px;
  cursor: pointer;
  transition: color .2s, border-color .2s, transform .15s, background .2s;
}
.theme-toggle:hover {
  color: var(--accent);
  border-color: var(--panel-border-hover);
  transform: translateY(-1px);
}
.theme-toggle:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}
.theme-toggle svg { display: block; }

/* show the moon icon in dark mode (so you can switch to light) */
:root[data-theme="dark"]  .theme-toggle .icon-sun  { display: none; }
:root[data-theme="dark"]  .theme-toggle .icon-moon { display: block; }
/* show the sun icon in light mode (so you can switch to dark) */
:root[data-theme="light"] .theme-toggle .icon-moon { display: none; }
:root[data-theme="light"] .theme-toggle .icon-sun  { display: block; }

/* ============================================================
   HERO
   ============================================================ */

.hero {
  padding: 5rem 0 3rem;
  position: relative;
}

.hero h1 {
  font-size: clamp(2.4rem, 6vw, 3.6rem);
  margin: 0 0 .5rem;
  font-weight: 600;
  letter-spacing: -.01em;
  background: linear-gradient(135deg, var(--hero-grad-from) 0%, var(--accent) 55%, var(--accent-2) 100%);
  -webkit-background-clip: text;
          background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
}

.tagline {
  font-family: var(--mono);
  color: var(--accent);
  font-size: .92rem;
  margin: 0 0 2rem;
  letter-spacing: .01em;
}

.bio p {
  margin: 0 0 1rem;
  color: var(--fg);
}

.bio strong { color: var(--fg); }
.bio em     { color: var(--accent-2); font-style: italic; }

.links-row {
  margin-top: 2rem;
  display: flex;
  flex-wrap: wrap;
  gap: .6rem;
}

.chip {
  display: inline-block;
  padding: .45rem .8rem;
  font-family: var(--mono);
  font-size: .82rem;
  border: 1px solid var(--panel-border);
  border-radius: 999px;
  background: var(--panel);
  color: var(--fg-dim);
}
.chip:hover {
  border-color: var(--accent-2);
  color: var(--accent-2);
}

/* ============================================================
   BLOCKS / SECTIONS
   ============================================================ */

.block {
  padding: 3rem 0;
  border-top: 1px solid var(--panel-border);
}

.block h2 {
  font-family: var(--mono);
  font-size: 1rem;
  font-weight: 500;
  letter-spacing: .15em;
  text-transform: uppercase;
  color: var(--fg-dim);
  margin: 0 0 1.5rem;
}
.bracket { color: var(--accent); }

.block-intro {
  color: var(--fg-dim);
  margin: 0 0 1.5rem;
}

/* ============================================================
   NOW CARD
   ============================================================ */

.card {
  border: 1px solid var(--panel-border);
  background: var(--panel);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  border-radius: 12px;
  padding: 1.5rem;
  position: relative;
  overflow: hidden;
  transition: border-color .25s;
}
.card::before {
  content: "";
  position: absolute;
  top: 0; left: 0;
  width: 3px; height: 100%;
  background: linear-gradient(180deg, var(--accent), var(--accent-2));
  opacity: .85;
}
.card:hover {
  border-color: var(--panel-border-hover);
}

.now-card h3 {
  margin: .25rem 0 .75rem;
  font-size: 1.25rem;
  color: var(--fg);
  font-weight: 600;
}

.card-meta {
  display: flex;
  flex-wrap: wrap;
  gap: .55rem;
  font-family: var(--mono);
  font-size: .78rem;
  margin-bottom: .35rem;
}
.meta-period {
  color: var(--accent);
  background: var(--accent-tint);
  border: 1px solid var(--accent-tint-2);
  padding: .15rem .55rem;
  border-radius: 4px;
  letter-spacing: .04em;
  text-transform: uppercase;
  font-size: .7rem;
}
.meta-loc {
  color: var(--fg-dim);
  padding: .15rem .25rem;
}

.tech-list {
  list-style: none;
  padding: 0;
  margin: 1rem 0 0;
  font-family: var(--mono);
  font-size: .85rem;
  color: var(--fg-dim);
}
.tech-list li {
  padding: .15rem 0 .15rem 1.1rem;
  position: relative;
}
.tech-list li::before {
  content: "▸";
  position: absolute;
  left: 0;
  color: var(--accent);
}

/* ============================================================
   PROJECTS
   ============================================================ */

.projects {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.25rem;
}

.project {
  border: 1px solid var(--panel-border);
  background: var(--panel);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  border-radius: 10px;
  padding: 1.25rem 1.4rem;
  transition: transform .2s, border-color .2s, box-shadow .2s;
  position: relative;
}
.project:hover {
  transform: translateY(-2px);
  border-color: var(--panel-border-hover);
  box-shadow: 0 10px 40px -20px var(--accent-tint-2);
}

.project header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: .35rem;
}

.project h3 {
  margin: 0;
  font-size: 1.08rem;
  color: var(--fg);
  font-weight: 600;
  letter-spacing: -.005em;
}

.project p {
  margin: .5rem 0;
  color: var(--fg);
}

/* high-contrast period chip, comparable to the active/done badges */
.project-period {
  display: inline-block;
  font-family: var(--mono);
  font-size: .72rem;
  color: var(--accent);
  background: var(--accent-tint);
  border: 1px solid var(--accent-tint-2);
  padding: .2rem .55rem;
  border-radius: 4px;
  letter-spacing: .05em;
  text-transform: uppercase;
  margin-top: .4rem !important;
  margin-bottom: .25rem !important;
}

.project-link {
  font-family: var(--mono);
  font-size: .82rem;
  color: var(--fg-dim);
}

.badge {
  font-family: var(--mono);
  font-size: .68rem;
  text-transform: uppercase;
  letter-spacing: .12em;
  padding: .2rem .55rem;
  border-radius: 999px;
  white-space: nowrap;
  flex-shrink: 0;
}
/* active = green (primary) */
.badge.active {
  background: var(--accent-tint);
  border: 1px solid var(--accent-tint-2);
  color: var(--accent);
}
/* done = turquoise/blue secondary */
.badge.done {
  background: var(--accent-2-tint);
  border: 1px solid var(--accent-2-tint-2);
  color: var(--accent-2);
}

.tag-row {
  display: flex;
  flex-wrap: wrap;
  gap: .35rem;
  margin-top: .75rem !important;
}
.tag {
  font-family: var(--mono);
  font-size: .72rem;
  color: var(--accent);
  background: var(--accent-tint);
  padding: .15rem .5rem;
  border: 1px solid var(--accent-tint-2);
  border-radius: 4px;
}

/* ============================================================
   PUBLICATIONS
   ============================================================ */

.pubs {
  list-style: none;
  padding: 0;
  margin: 0;
  counter-reset: pub;
}
.pubs li {
  position: relative;
  padding: .75rem 0 .75rem 2.5rem;
  border-bottom: 1px dashed var(--panel-border);
  counter-increment: pub;
}
.pubs li:last-child { border-bottom: none; }
.pubs li::before {
  content: "[" counter(pub) "]";
  position: absolute;
  left: 0;
  top: .85rem;
  font-family: var(--mono);
  font-size: .78rem;
  color: var(--accent);
}
/* author names — keep emphasis but plain weight, not white-bolded */
.pubs strong {
  color: var(--fg);
  font-weight: 500;
}
.pubs em { color: var(--fg); font-style: italic; }
/* journal venues — plain italic, no green */
.venue {
  color: var(--fg);
  font-style: italic;
}

/* ============================================================
   EDUCATION
   ============================================================ */

.education {
  list-style: none;
  padding: 0;
  margin: 0;
}
.education li {
  padding: 1rem 0;
  border-bottom: 1px dashed var(--panel-border);
  display: grid;
  grid-template-columns: 1fr;
  gap: .25rem;
}
.education li:last-child { border-bottom: none; }
.education strong { color: var(--fg); font-size: 1.05rem; }
.ed-sub {
  font-family: var(--mono);
  font-size: .82rem;
  color: var(--accent);
}
.ed-detail { color: var(--fg-dim); }

/* ============================================================
   CONTACT
   ============================================================ */

.contact-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: .9rem;
}
.contact-card {
  border: 1px solid var(--panel-border);
  background: var(--panel);
  border-radius: 10px;
  padding: 1rem 1.1rem;
  display: flex;
  flex-direction: column;
  gap: .25rem;
  font-family: var(--mono);
  font-size: .85rem;
  transition: border-color .2s, transform .2s;
}
.contact-card:hover {
  border-color: var(--accent-2);
  transform: translateY(-2px);
  color: var(--fg);
}
.ck { color: var(--fg-faint); font-size: .72rem; text-transform: uppercase; letter-spacing: .15em; }
.cv { color: var(--accent-2); }

/* ============================================================
   FOOTER
   ============================================================ */

.site-footer {
  border-top: 1px solid var(--panel-border);
  margin-top: 4rem;
  padding: 1.5rem 0 2.5rem;
  font-family: var(--mono);
  font-size: .78rem;
  color: var(--fg-faint);
}
.site-footer .container {
  display: flex;
  flex-wrap: wrap;
  gap: .5rem;
  justify-content: center;
  text-align: center;
}
.footer-sep { color: var(--accent); }

/* ============================================================
   RESPONSIVE
   ============================================================ */

@media (max-width: 640px) {
  .site-header .container { padding-top: .75rem; padding-bottom: .75rem; }
  .site-nav { gap: .75rem; font-size: .78rem; }
  .hero { padding: 3rem 0 2rem; }
  .block { padding: 2rem 0; }
  .project header { flex-direction: column; }
  .badge { align-self: flex-start; }
}

/* reduce motion preference */
@media (prefers-reduced-motion: reduce) {
  .cursor { animation: none; }
  html { scroll-behavior: auto; }
}