/* =========================================================
   Maciej Bielecki — .NET Developer portfolio
   Zero-build, dependency-free stylesheet.
   ========================================================= */

/* ---------- Reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
html, body, h1, h2, h3, h4, p, ul, ol, figure, blockquote { margin: 0; }
ul { padding: 0; list-style: none; }
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; background: none; border: none; cursor: pointer; }
html { -webkit-text-size-adjust: 100%; }

/* ---------- Design tokens ---------- */
:root {
  --font-sans: -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, "SFMono-Regular", Menlo, Consolas, "Liberation Mono", monospace;

  --accent: #5b6ef5;
  --accent-strong: #4453e0;
  --accent-soft: rgba(91, 110, 245, 0.14);
  --teal: #1fc8a1;

  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 22px;

  --space-1: 0.4rem;
  --space-2: 0.8rem;
  --space-3: 1.4rem;
  --space-4: 2.2rem;
  --space-5: 3.6rem;
  --space-6: 5.6rem;

  --max-w: 1120px;

  --shadow: 0 10px 40px -14px rgba(10, 12, 20, 0.5);

  /* Dark theme (default) */
  --bg: #0a0c11;
  --bg-elevated: #12151d;
  --surface: #151924;
  --surface-hover: #1b202e;
  --border: #232838;
  --text: #eef0f6;
  --text-muted: #9aa1b5;
  --text-dim: #6a7188;
}

:root[data-theme="light"] {
  --bg: #fafafc;
  --bg-elevated: #ffffff;
  --surface: #ffffff;
  --surface-hover: #f2f3f9;
  --border: #e4e6ef;
  --text: #14161f;
  --text-muted: #565d72;
  --text-dim: #868da3;
  --accent-soft: rgba(91, 110, 245, 0.1);
  --shadow: 0 10px 30px -16px rgba(30, 34, 60, 0.18);
}

@media (prefers-color-scheme: light) {
  :root:not([data-theme="dark"]) {
    --bg: #fafafc;
    --bg-elevated: #ffffff;
    --surface: #ffffff;
    --surface-hover: #f2f3f9;
    --border: #e4e6ef;
    --text: #14161f;
    --text-muted: #565d72;
    --text-dim: #868da3;
    --accent-soft: rgba(91, 110, 245, 0.1);
    --shadow: 0 10px 30px -16px rgba(30, 34, 60, 0.18);
  }
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  line-height: 1.6;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  transition: background-color 0.25s ease, color 0.25s ease;
}

.container {
  max-width: var(--max-w);
  margin-inline: auto;
  padding-inline: var(--space-3);
}

.visually-hidden {
  position: absolute;
  width: 1px; height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

.skip-link {
  position: absolute;
  top: -100%;
  left: var(--space-3);
  background: var(--accent);
  color: #fff;
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-sm);
  z-index: 200;
  transition: top 0.2s ease;
}
.skip-link:focus { top: var(--space-2); }

/* ---------- Typography ---------- */
h1, h2, h3, h4 { font-weight: 700; letter-spacing: -0.02em; }
h1 { font-size: clamp(2.1rem, 5vw, 3.4rem); line-height: 1.12; }
h2 { font-size: clamp(1.6rem, 3.4vw, 2.2rem); line-height: 1.2; }
h3 { font-size: 1.2rem; }
.eyebrow {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  margin-bottom: var(--space-2);
}
.eyebrow::before {
  content: "";
  width: 8px; height: 8px;
  border-radius: 50%;
  background: var(--teal);
  box-shadow: 0 0 0 4px var(--accent-soft);
}
.section-lead {
  color: var(--text-muted);
  max-width: 62ch;
  font-size: 1.05rem;
}
code, .mono { font-family: var(--font-mono); }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5em;
  padding: 0.85em 1.5em;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 0.95rem;
  transition: transform 0.15s ease, background-color 0.15s ease, border-color 0.15s ease;
  border: 1px solid transparent;
  white-space: nowrap;
}
.btn:hover { transform: translateY(-2px); }
.btn:active { transform: translateY(0); }
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: var(--accent-strong); }
.btn-outline { border-color: var(--border); color: var(--text); background: var(--surface); }
.btn-outline:hover { border-color: var(--accent); background: var(--surface-hover); }
.btn-ghost { color: var(--text-muted); }
.btn-ghost:hover { color: var(--text); }

/* ---------- Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: saturate(140%) blur(10px);
  background: color-mix(in srgb, var(--bg) 78%, transparent);
  border-bottom: 1px solid var(--border);
}
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-block: var(--space-2);
  gap: var(--space-3);
}
.logo {
  display: flex;
  align-items: center;
  gap: 0.6em;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 1.05rem;
}
.logo-mark {
  width: 36px; height: 36px;
  border-radius: 10px;
  background: linear-gradient(135deg, var(--accent), var(--teal));
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.95rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  flex: none;
}
.nav-links {
  display: flex;
  gap: var(--space-4);
  font-size: 0.95rem;
  color: var(--text-muted);
}
.nav-links a { transition: color 0.15s ease; position: relative; }
.nav-links a:hover, .nav-links a:focus-visible { color: var(--text); }
.nav-actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}
.icon-btn {
  width: 38px; height: 38px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background: var(--surface);
}
.icon-btn:hover { background: var(--surface-hover); border-color: var(--accent); }
.icon-btn svg { width: 18px; height: 18px; }
.lang-switch { display: flex; border: 1px solid var(--border); border-radius: var(--radius-sm); overflow: hidden; }
.lang-switch a { padding: 0.5em 0.75em; font-family: var(--font-mono); font-size: 0.8rem; color: var(--text-dim); }
.lang-switch a[aria-current="page"] { background: var(--accent-soft); color: var(--accent); font-weight: 700; }
.lang-switch a:hover { color: var(--text); }

.nav-toggle { display: none; }
@media (max-width: 860px) {
  .nav-links { display: none; }
  .nav-toggle { display: inline-flex; }
}

.mobile-menu {
  display: none;
  flex-direction: column;
  padding: var(--space-2) var(--space-3) var(--space-3);
  border-top: 1px solid var(--border);
  gap: var(--space-1);
}
.mobile-menu.open { display: flex; }
.mobile-menu a { padding: var(--space-2) 0; color: var(--text-muted); border-bottom: 1px solid var(--border); }
.mobile-menu a:last-child { border-bottom: none; }

/* ---------- Hero ---------- */
.hero {
  padding-block: clamp(3rem, 8vw, var(--space-6)) var(--space-5);
  position: relative;
  overflow: clip;
}
.hero::before {
  content: "";
  position: absolute;
  inset: -20% -10% auto -10%;
  height: 480px;
  background: radial-gradient(closest-side, var(--accent-soft), transparent 70%);
  z-index: -1;
  pointer-events: none;
}
.hero-grid {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: var(--space-5);
  align-items: center;
}
@media (max-width: 900px) {
  .hero-grid { grid-template-columns: 1fr; }
}
.hero-summary {
  color: var(--text-muted);
  font-size: 1.12rem;
  margin-block: var(--space-3) var(--space-4);
  max-width: 58ch;
}
.hero-actions { display: flex; flex-wrap: wrap; gap: var(--space-2); margin-bottom: var(--space-4); }
.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
  font-size: 0.9rem;
  color: var(--text-dim);
}
.hero-meta strong { color: var(--text); display: block; font-size: 1.3rem; font-family: var(--font-mono); }

.terminal {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow);
  overflow: hidden;
}
.terminal-bar {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-3);
  border-bottom: 1px solid var(--border);
  background: var(--surface);
}
.terminal-dot { width: 11px; height: 11px; border-radius: 50%; background: var(--border); }
.terminal-dot:nth-child(1) { background: #ff5f57; }
.terminal-dot:nth-child(2) { background: #febc2e; }
.terminal-dot:nth-child(3) { background: #28c840; }
.terminal-title { margin-left: var(--space-2); font-family: var(--font-mono); font-size: 0.8rem; color: var(--text-dim); }
.terminal-body {
  padding: var(--space-3);
  font-family: var(--font-mono);
  font-size: 0.86rem;
  min-height: 220px;
  color: var(--text-muted);
  line-height: 1.75;
}
.terminal-body .prompt { color: var(--teal); }
.terminal-body .path { color: var(--accent); }
.terminal-line { white-space: pre-wrap; }
.cursor { display: inline-block; width: 7px; height: 1.05em; background: var(--accent); vertical-align: text-bottom; animation: blink 1s step-end infinite; }
@keyframes blink { 50% { opacity: 0; } }

/* ---------- Sections ---------- */
section { padding-block: var(--space-6); border-top: 1px solid var(--border); }
section:first-of-type { border-top: none; }
.section-head { margin-bottom: var(--space-4); }

/* Progressive enhancement: content is visible by default (no-JS, slow/blocked
   scripts). The scroll-reveal animation only applies once main.js confirms it
   is running by tagging <html class="js"> before first paint. */
.reveal { transition: opacity 0.6s ease, transform 0.6s ease; }
html.js .reveal { opacity: 0; transform: translateY(18px); }
.reveal.in-view { opacity: 1; transform: translateY(0); }

/* Quick facts under about */
.fact-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-3);
  margin-top: var(--space-4);
}
@media (max-width: 760px) { .fact-grid { grid-template-columns: repeat(2, 1fr); } }
.fact {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: var(--space-3);
}
.fact strong { display: block; font-size: 1.5rem; font-family: var(--font-mono); color: var(--accent); }
.fact span { color: var(--text-dim); font-size: 0.88rem; }

/* Timeline (experience) */
.timeline { display: flex; flex-direction: column; gap: 0; position: relative; }
.timeline-item {
  position: relative;
  padding: var(--space-3) 0 var(--space-3) var(--space-5);
  border-left: 2px solid var(--border);
  margin-left: 6px;
}
.timeline-item:last-child { border-left-color: transparent; background: linear-gradient(var(--border), transparent 40%) 0 0 / 2px 100% no-repeat; }
.timeline-item::before {
  content: "";
  position: absolute;
  left: -7px; top: var(--space-3);
  width: 12px; height: 12px;
  border-radius: 50%;
  background: var(--bg);
  border: 2px solid var(--accent);
}
.timeline-item.current::before { background: var(--teal); border-color: var(--teal); box-shadow: 0 0 0 4px var(--accent-soft); }
.timeline-head { display: flex; flex-wrap: wrap; align-items: baseline; gap: var(--space-2) var(--space-3); margin-bottom: var(--space-1); }
.timeline-role { font-size: 1.15rem; font-weight: 700; }
.timeline-company { color: var(--accent); font-weight: 600; }
.timeline-dates { margin-left: auto; font-family: var(--font-mono); font-size: 0.82rem; color: var(--text-dim); }
.timeline-item p.summary { color: var(--text-muted); margin-block: var(--space-2); }
.tag-row { display: flex; flex-wrap: wrap; gap: 0.4em; margin-bottom: var(--space-2); }
.tag {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  padding: 0.25em 0.6em;
  border-radius: 999px;
  border: 1px solid var(--border);
  color: var(--text-muted);
  background: var(--surface);
}
.timeline-bullets { display: flex; flex-direction: column; gap: 0.4em; color: var(--text-muted); }
.timeline-bullets li { position: relative; padding-left: 1.1em; }
.timeline-bullets li::before { content: "→"; position: absolute; left: 0; color: var(--accent); }

/* Project / case-study cards */
.project-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-3);
}
@media (max-width: 980px) { .project-grid { grid-template-columns: 1fr; } }
.project-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--space-4);
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  transition: border-color 0.2s ease, transform 0.2s ease;
}
.project-card:hover { border-color: var(--accent); transform: translateY(-4px); }
.project-icon {
  width: 44px; height: 44px;
  border-radius: var(--radius-sm);
  background: var(--accent-soft);
  color: var(--accent);
  display: flex; align-items: center; justify-content: center;
}
.project-card h3 { margin-top: var(--space-1); }
.project-meta { font-family: var(--font-mono); font-size: 0.78rem; color: var(--text-dim); }
.project-block { font-size: 0.92rem; }
.project-block b { color: var(--text); display: block; font-size: 0.78rem; text-transform: uppercase; letter-spacing: 0.06em; color: var(--text-dim); margin-bottom: 0.2em; }
.project-block p { color: var(--text-muted); }

/* Skills */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-3);
}
@media (max-width: 760px) { .skills-grid { grid-template-columns: 1fr; } }
.skill-group {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: var(--space-3);
}
.skill-group h3 { font-size: 0.95rem; color: var(--text-dim); text-transform: uppercase; letter-spacing: 0.06em; font-weight: 700; margin-bottom: var(--space-2); }
.skill-tags { display: flex; flex-wrap: wrap; gap: 0.5em; }
.skill-tags .tag { color: var(--text); }
.skill-group.ai { border-color: var(--accent); background: linear-gradient(160deg, var(--accent-soft), transparent 60%); grid-column: 1 / -1; }

/* Education */
.edu-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: var(--space-3); }
@media (max-width: 760px) { .edu-grid { grid-template-columns: 1fr; } }
.edu-card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius-md); padding: var(--space-3); }
.edu-card .timeline-dates { margin-left: 0; }

/* Blog teaser */
.blog-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: var(--space-3); }
@media (max-width: 980px) { .blog-grid { grid-template-columns: 1fr; } }
.blog-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: var(--space-3);
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}
.blog-card time { font-family: var(--font-mono); font-size: 0.78rem; color: var(--accent); }
.blog-card p { color: var(--text-muted); font-size: 0.92rem; }
.blog-empty {
  grid-column: 1 / -1;
  text-align: center;
  padding: var(--space-4);
  color: var(--text-dim);
  border: 1px dashed var(--border);
  border-radius: var(--radius-md);
}

/* Contact */
.contact-grid { display: grid; grid-template-columns: 1.1fr 0.9fr; gap: var(--space-4); align-items: start; }
@media (max-width: 860px) { .contact-grid { grid-template-columns: 1fr; } }
.contact-list { display: flex; flex-direction: column; gap: var(--space-2); }
.contact-row {
  display: flex; align-items: center; gap: var(--space-3);
  padding: var(--space-3);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  transition: border-color 0.15s ease, transform 0.15s ease;
}
.contact-row:hover { border-color: var(--accent); transform: translateX(4px); }
.contact-row .icon-btn { pointer-events: none; }
.contact-row div span { display: block; color: var(--text-dim); font-size: 0.8rem; }
.cv-download { display: flex; flex-direction: column; gap: var(--space-2); }
.cv-download .btn { justify-content: center; }

/* Footer */
footer {
  border-top: 1px solid var(--border);
  padding-block: var(--space-4);
  color: var(--text-dim);
  font-size: 0.85rem;
}
.footer-row { display: flex; flex-wrap: wrap; justify-content: space-between; align-items: center; gap: var(--space-2); }
.footer-row a:hover { color: var(--text); }

/* Utility */
.gap { display: flex; gap: var(--space-2); flex-wrap: wrap; }

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: 0.001ms !important; transition-duration: 0.001ms !important; }
  /* !important needed: html.js .reveal (0,2,1) otherwise outranks this plain
     .reveal selector (0,1,0) and would keep content hidden for reduced-motion users. */
  .reveal { opacity: 1 !important; transform: none !important; }
}