/* trotsky.dev — single-page portfolio.
 * Implements the "Portfolio Page" design (claude.ai/design project
 * 4f26505a-8fec-4b7e-a614-39948ad7723d, PortfolioPage.dc.html) as static
 * CSS. Tokens are copied verbatim from the design system; component rules
 * translate its React components 1:1.
 */

/* ---------------- Webfonts (self-hosted, latin subset, variable) ---------------- */

@font-face {
  font-family: 'Inter';
  font-style: normal;
  font-weight: 400 700;
  font-display: swap;
  src: url('fonts/inter-latin.woff2') format('woff2');
}
@font-face {
  font-family: 'JetBrains Mono';
  font-style: normal;
  font-weight: 400 500;
  font-display: swap;
  src: url('fonts/jetbrains-mono-latin.woff2') format('woff2');
}

/* ---------------- Color tokens (dark-first) ---------------- */

:root {
  --ink-900: #0B0F14;
  --ink-800: #11161D;
  --ink-700: #1B242C;
  --ink-600: #263340;

  --paper-50: #F8FAFC;
  --paper-0:  #FFFFFF;
  --line-200: #E5E7EB;

  --fg-050: #E6E7EA;
  --fg-400: #94A3B8;
  --fg-600: #475569;
  --fg-900: #0F172A;

  --blue-500: #3B82F6;
  --blue-600: #2563EB;
  --blue-400: #60A5FA;
  --blue-700: #1D4ED8;

  --surface-page:    var(--ink-900);
  --surface-card:    var(--ink-800);
  --surface-raised:  var(--ink-700);
  --surface-hover:   #131A22;

  --border-default:  var(--ink-700);
  --border-strong:   var(--ink-600);

  --text-primary:    var(--fg-050);
  --text-secondary:  #C2CAD6;
  --text-muted:      var(--fg-400);

  --accent:          var(--blue-500);
  --accent-hover:    var(--blue-400);
  --accent-contrast: #FFFFFF;

  --focus-ring:      var(--blue-500);
  --selection-bg:    rgba(59, 130, 246, 0.28);

  --hairline:        rgba(255, 255, 255, 0.06);

  --tag-violet-fg: #C4B5FD; --tag-violet-bg: rgba(139,92,246,0.14); --tag-violet-bd: rgba(139,92,246,0.30);
  --tag-emerald-fg: #6EE7B7; --tag-emerald-bg: rgba(16,185,129,0.13); --tag-emerald-bd: rgba(16,185,129,0.30);
  --tag-rose-fg: #FDA4AF; --tag-rose-bg: rgba(244,63,94,0.13); --tag-rose-bd: rgba(244,63,94,0.30);
  --tag-sky-fg: #7DD3FC; --tag-sky-bg: rgba(14,165,233,0.13); --tag-sky-bd: rgba(14,165,233,0.30);
  --tag-cyan-fg: #67E8F9; --tag-cyan-bg: rgba(6,182,212,0.13); --tag-cyan-bd: rgba(6,182,212,0.30);
  --tag-teal-fg: #5EEAD4; --tag-teal-bg: rgba(20,184,166,0.13); --tag-teal-bd: rgba(20,184,166,0.30);
  --tag-amber-fg: #FCD34D; --tag-amber-bg: rgba(245,158,11,0.13); --tag-amber-bd: rgba(245,158,11,0.30);
}

[data-theme="light"] {
  --surface-page:    var(--paper-50);
  --surface-card:    var(--paper-0);
  --surface-raised:  var(--paper-0);
  --surface-hover:   #F1F5F9;

  --border-default:  var(--line-200);
  --border-strong:   #D3D9E0;

  --text-primary:    var(--fg-900);
  --text-secondary:  #334155;
  --text-muted:      var(--fg-600);

  --accent:          var(--blue-600);
  --accent-hover:    var(--blue-700);
  --accent-contrast: #FFFFFF;

  --focus-ring:      var(--blue-600);
  --selection-bg:    rgba(37, 99, 235, 0.18);

  --hairline:        rgba(15, 23, 42, 0.06);

  --tag-violet-fg: #6D28D9; --tag-violet-bg: rgba(139,92,246,0.10); --tag-violet-bd: rgba(139,92,246,0.28);
  --tag-emerald-fg: #047857; --tag-emerald-bg: rgba(16,185,129,0.10); --tag-emerald-bd: rgba(16,185,129,0.28);
  --tag-rose-fg: #BE123C; --tag-rose-bg: rgba(244,63,94,0.09); --tag-rose-bd: rgba(244,63,94,0.26);
  --tag-sky-fg: #0369A1; --tag-sky-bg: rgba(14,165,233,0.10); --tag-sky-bd: rgba(14,165,233,0.28);
  --tag-cyan-fg: #0E7490; --tag-cyan-bg: rgba(6,182,212,0.10); --tag-cyan-bd: rgba(6,182,212,0.28);
  --tag-teal-fg: #0F766E; --tag-teal-bg: rgba(20,184,166,0.10); --tag-teal-bd: rgba(20,184,166,0.28);
  --tag-amber-fg: #B45309; --tag-amber-bg: rgba(245,158,11,0.11); --tag-amber-bd: rgba(245,158,11,0.30);
}

/* ---------------- Typography / spacing / effects tokens ---------------- */

:root {
  --font-sans: 'Inter', ui-sans-serif, system-ui, -apple-system, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  --font-mono: 'JetBrains Mono', ui-monospace, 'SF Mono', 'Cascadia Code', Menlo, Consolas, monospace;

  --weight-regular: 400;
  --weight-medium: 500;
  --weight-semibold: 600;
  --weight-bold: 700;

  --text-h1: 3.5rem;
  --text-h2: 2rem;
  --text-h3: 1.5rem;
  --text-body: 1rem;
  --text-small: 0.875rem;
  --text-caption: 0.75rem;

  --leading-h1: 4rem;
  --leading-h2: 2.5rem;
  --leading-h3: 2rem;
  --leading-body: 1.5rem;
  --leading-small: 1.25rem;
  --leading-caption: 1rem;

  --tracking-tight: -0.02em;
  --tracking-wide: 0.04em;

  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-24: 6rem;

  --container-max: 1120px;
  --gutter: 1.5rem;
  --gutter-lg: 2rem;

  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-full: 999px;

  --shadow-card: 0 1px 2px rgba(0, 0, 0, 0.25);
  --shadow-card-hover: 0 8px 28px rgba(0, 0, 0, 0.35);

  --ease-out: cubic-bezier(0.22, 1, 0.36, 1);
  --ease-standard: cubic-bezier(0.4, 0, 0.2, 1);
  --dur-fast: 120ms;
  --dur-base: 180ms;
}

[data-theme="light"] {
  --shadow-card: 0 1px 2px rgba(15, 23, 42, 0.06);
  --shadow-card-hover: 0 10px 30px rgba(15, 23, 42, 0.10);
}

@media (prefers-reduced-motion: reduce) {
  :root { --dur-fast: 0ms; --dur-base: 0ms; }
}

/* Step the display size down on small screens (360px must not clip). */
@media (max-width: 480px) {
  :root { --text-h1: 2.5rem; --leading-h1: 3rem; }
}

/* ---------------- Base ---------------- */

*, *::before, *::after { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--surface-page);
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: var(--text-body);
  line-height: var(--leading-body);
  font-weight: var(--weight-regular);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

::selection { background: var(--selection-bg); }

a {
  color: var(--accent);
  text-decoration: none;
  transition: color var(--dur-fast) var(--ease-standard);
}
a:hover { color: var(--accent-hover); }

:focus-visible {
  outline: 2px solid var(--focus-ring);
  outline-offset: 2px;
  border-radius: 3px;
}

h1, h2, h3, h4, p { margin: 0; }

svg { display: inline-block; flex-shrink: 0; }

/* ---------------- Page shell ---------------- */

.page {
  min-height: 100vh;
  background: var(--surface-page);
  overflow-x: clip;
}

main {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--gutter-lg);
}

@media (max-width: 640px) {
  main { padding: 0 var(--gutter); }
}

/* ---------------- NavBar ---------------- */

.nav {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-6);
  padding: 18px var(--gutter);
  background: color-mix(in srgb, var(--surface-page) 82%, transparent);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border-default);
}

.wordmark {
  font-weight: var(--weight-bold);
  font-size: 18px;
  letter-spacing: var(--tracking-tight);
  color: var(--text-primary);
}
.wordmark:hover { color: var(--text-primary); }
.wordmark .tld { color: var(--accent); }

.nav nav { display: flex; align-items: center; gap: var(--space-6); }

.nav-links { display: flex; align-items: center; gap: var(--space-6); }
.nav-links a {
  font-size: var(--text-small);
  font-weight: var(--weight-medium);
  color: var(--text-muted);
}
.nav-links a:hover { color: var(--text-primary); }

.nav-menu {
  display: none;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  padding: 0;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-default);
  background: var(--surface-raised);
  color: var(--text-primary);
  cursor: pointer;
}

/* Mobile menu panel (design leaves the open state unspecified — quiet dropdown) */
.nav-panel {
  display: none;
  position: absolute;
  top: calc(100% + 8px);
  right: var(--gutter);
  flex-direction: column;
  min-width: 160px;
  padding: var(--space-2);
  background: var(--surface-card);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card-hover);
}
.nav-panel a {
  padding: 10px 12px;
  border-radius: var(--radius-md);
  font-size: var(--text-small);
  font-weight: var(--weight-medium);
  color: var(--text-primary);
}
.nav-panel a:hover { background: var(--surface-hover); color: var(--text-primary); }
[data-theme="light"] .nav-panel a:hover { background: var(--surface-hover); }

.nav.menu-open .nav-panel { display: flex; }

@media (max-width: 640px) {
  .nav-links { display: none; }
  .nav-menu { display: inline-flex; }
}

/* ---------------- Theme toggle ---------------- */

.theme-toggle {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  height: 28px;
  padding: 0 6px 0 8px;
  border-radius: var(--radius-full);
  border: 1px solid var(--border-default);
  background: var(--surface-raised);
  color: var(--text-muted);
  cursor: pointer;
  transition: border-color var(--dur-fast) var(--ease-standard);
}
.theme-toggle:hover { border-color: var(--border-strong); }
.theme-toggle .icon-sun, .theme-toggle .icon-moon { color: var(--accent); }
.theme-toggle .icon-sun { display: none; }
[data-theme="light"] .theme-toggle .icon-moon { display: none; }
[data-theme="light"] .theme-toggle .icon-sun { display: inline-block; }

.theme-toggle .track {
  position: relative;
  width: 34px;
  height: 16px;
  border-radius: var(--radius-full);
  background: var(--border-strong);
  transition: background var(--dur-base) var(--ease-standard);
}
[data-theme="light"] .theme-toggle .track { background: var(--accent); }

.theme-toggle .thumb {
  position: absolute;
  top: 2px;
  left: 2px;
  width: 12px;
  height: 12px;
  border-radius: var(--radius-full);
  background: #fff;
  transition: left var(--dur-base) var(--ease-out);
}
[data-theme="light"] .theme-toggle .thumb { left: 20px; }

/* ---------------- Hero ---------------- */

.hero {
  position: relative;
  padding-top: var(--space-24);
  padding-bottom: var(--space-16);
}

.hero-art {
  position: absolute;
  top: -40px;
  right: -80px;
  width: 460px;
  height: 460px;
  opacity: 0.6;
  pointer-events: none;
}

.hero h1 {
  font-size: var(--text-h1);
  line-height: var(--leading-h1);
  font-weight: var(--weight-bold);
  letter-spacing: var(--tracking-tight);
  color: var(--text-primary);
}

.hero .tagline {
  margin-top: var(--space-5);
  font-size: var(--text-h3);
  line-height: var(--leading-h3);
  color: var(--text-secondary);
  max-width: 620px;
}
.hero .tagline .accent { color: var(--accent); }

.hero .contacts {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-8);
  margin-top: var(--space-8);
}

/* ---------------- ContactLink ---------------- */

.contact-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-body);
  font-weight: var(--weight-medium);
  color: var(--text-primary);
}
.contact-link:hover { color: var(--accent); }
.contact-link.sm { font-size: var(--text-small); }

/* ---------------- Sections ---------------- */

section h2 {
  font-size: var(--text-h2);
  line-height: var(--leading-h2);
  font-weight: var(--weight-semibold);
  letter-spacing: var(--tracking-tight);
  color: var(--text-primary);
  margin-bottom: var(--space-8);
}

#projects { padding-top: var(--space-12); scroll-margin-top: 80px; }
#about { padding-top: var(--space-24); scroll-margin-top: 80px; }

/* ---------------- Projects grid + cards ---------------- */

.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--space-5);
  align-items: stretch;
}

.project-card {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  padding: var(--space-5);
  background: var(--surface-card);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
  transform: translateY(0);
  transition:
    transform var(--dur-base) var(--ease-out),
    border-color var(--dur-base) var(--ease-standard),
    box-shadow var(--dur-base) var(--ease-standard);
}
.project-card:hover {
  border-color: var(--border-strong);
  box-shadow: var(--shadow-card-hover);
  transform: translateY(-2px);
}

.project-card .head {
  display: flex;
  align-items: flex-start;
  gap: var(--space-3);
}
.project-card .head > div {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  padding-top: 2px;
}
.project-card h3 {
  font-size: var(--text-h3);
  line-height: var(--leading-h3);
  font-weight: var(--weight-semibold);
  color: var(--text-primary);
}
.project-card .desc {
  font-size: var(--text-small);
  line-height: var(--leading-small);
  color: var(--text-muted);
}

.project-card .tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.project-card .live {
  margin-top: auto;
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  align-self: flex-start;
  font-family: var(--font-mono);
  font-size: var(--text-small);
  font-weight: var(--weight-medium);
  color: var(--accent);
}
.project-card .live:hover { color: var(--accent-hover); }

/* ---------------- Badge / Tag / SkillPill ---------------- */

.badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  font-family: var(--font-mono);
  font-weight: var(--weight-semibold);
  font-size: 17px;
  line-height: 1;
  user-select: none;
}

.tag {
  display: inline-flex;
  align-items: center;
  font-family: var(--font-mono);
  font-size: var(--text-caption);
  line-height: 1;
  font-weight: var(--weight-medium);
  padding: 5px 8px;
  border-radius: var(--radius-sm);
  white-space: nowrap;
}

.hue-violet  { color: var(--tag-violet-fg);  background: var(--tag-violet-bg);  border: 1px solid var(--tag-violet-bd); }
.hue-emerald { color: var(--tag-emerald-fg); background: var(--tag-emerald-bg); border: 1px solid var(--tag-emerald-bd); }
.hue-rose    { color: var(--tag-rose-fg);    background: var(--tag-rose-bg);    border: 1px solid var(--tag-rose-bd); }
.hue-sky     { color: var(--tag-sky-fg);     background: var(--tag-sky-bg);     border: 1px solid var(--tag-sky-bd); }
.hue-cyan    { color: var(--tag-cyan-fg);    background: var(--tag-cyan-bg);    border: 1px solid var(--tag-cyan-bd); }
.hue-teal    { color: var(--tag-teal-fg);    background: var(--tag-teal-bg);    border: 1px solid var(--tag-teal-bd); }
.hue-amber   { color: var(--tag-amber-fg);   background: var(--tag-amber-bg);   border: 1px solid var(--tag-amber-bd); }

.skills {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  margin-top: var(--space-8);
}

.skill-pill {
  display: inline-flex;
  align-items: center;
  font-size: var(--text-small);
  line-height: 1;
  color: var(--text-secondary);
  padding: 9px 14px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-default);
  background: transparent;
  white-space: nowrap;
}

/* ---------------- About ---------------- */

#about .bio {
  font-size: var(--text-body);
  line-height: 1.7;
  color: var(--text-secondary);
  max-width: 680px;
}

/* ---------------- Footer ---------------- */

.footer-wrap { padding-top: var(--space-24); padding-bottom: var(--space-12); }

footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-4);
  padding-top: var(--space-8);
  border-top: 1px solid var(--border-default);
}
footer .copyright {
  font-size: var(--text-small);
  color: var(--text-muted);
}
footer .links {
  display: flex;
  align-items: center;
  gap: var(--space-6);
}