:root {
  --color-bg: #ffffff;
  --color-text: #0b1220;
  --color-muted: #475569;
  --color-faint: #64748b;
  --color-border: #e2e8f0;
  --color-surface: #f8fafc;
  --color-accent: #0f766e;
  --color-accent-strong: #14b8a6;
  --color-accent-soft: #ccfbf1;
  --color-on-accent: #042f2e;

  --color-hero-bg: #0b1220;
  --color-hero-text: #f1f5f9;
  --color-hero-muted: #94a3b8;
  --color-hero-border: rgba(148, 163, 184, 0.18);

  --tint-cloud: #0ea5e9;
  --tint-ai: #8b5cf6;
  --tint-security: #14b8a6;

  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Inter, Roboto, Helvetica, Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "JetBrains Mono", Menlo, Consolas, monospace;

  --max-width: 1120px;
  --gutter: 20px;
  --radius: 12px;
  --shadow: 0 1px 2px rgba(15, 23, 42, 0.04), 0 8px 24px rgba(15, 23, 42, 0.06);
  --transition: 0.15s ease;
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #0b1220;
    --color-text: #e2e8f0;
    --color-muted: #94a3b8;
    --color-faint: #7c8aa0;
    --color-border: #1e293b;
    --color-surface: #111a2e;
    --color-accent: #2dd4bf;
    --color-accent-soft: rgba(45, 212, 191, 0.12);
    --color-hero-bg: #070c17;
    --shadow: 0 1px 2px rgba(0, 0, 0, 0.3), 0 8px 24px rgba(0, 0, 0, 0.35);
  }
}

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

html {
  scroll-behavior: smooth;
}

body {
  background-color: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-sans);
  font-size: 16px;
  font-weight: 400;
  line-height: 1.65;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a {
  color: inherit;
}

a:focus-visible,
button:focus-visible {
  outline: 2px solid var(--color-accent-strong);
  outline-offset: 2px;
}

.site-container {
  position: relative;
  max-width: 100%;
}

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

/* ---------- Header ---------- */

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px 16px;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 18px var(--gutter);
  font-size: 17px;
  font-weight: 600;
}

.site-header a {
  text-decoration: none;
  color: var(--color-text);
}

.wordmark {
  font-family: var(--font-mono);
  font-size: 22px;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.wordmark span {
  color: var(--color-accent-strong);
}

.site-header--dark {
  color: var(--color-hero-text);
}

.site-header--dark a,
.site-header--dark .menu a {
  color: var(--color-hero-text);
}

.menu {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 2px;
  list-style: none;
}

.menu a {
  display: block;
  padding: 6px 12px;
  border-radius: 8px;
  text-decoration: none;
  color: var(--color-text);
  font-size: 15px;
  font-weight: 500;
  transition: color var(--transition), background-color var(--transition);
}

.menu a:hover {
  color: var(--color-accent);
  background-color: var(--color-surface);
}

.site-header--dark .menu a:hover {
  color: #ffffff;
  background-color: rgba(148, 163, 184, 0.12);
}

.menu a[aria-current="page"] {
  color: var(--color-accent);
}

.site-header--dark .menu a[aria-current="page"] {
  color: var(--color-accent-strong);
}

.menu .menu-cta {
  margin-left: 6px;
  background-color: var(--color-accent-strong);
  color: var(--color-on-accent);
  font-weight: 600;
}

.site-header--dark .menu .menu-cta {
  color: var(--color-on-accent);
}

.menu .menu-cta[aria-current="page"] {
  color: var(--color-on-accent);
}

.menu .menu-cta:hover,
.site-header--dark .menu .menu-cta:hover {
  background-color: #5eead4;
  color: var(--color-on-accent);
}

/* ---------- Buttons ---------- */

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 20px;
  border-radius: 10px;
  font-size: 15px;
  font-weight: 600;
  text-decoration: none;
  transition: background-color var(--transition), border-color var(--transition), transform var(--transition);
}

.btn:hover {
  transform: translateY(-1px);
}

.btn-primary {
  background-color: var(--color-accent-strong);
  color: var(--color-on-accent);
}

.btn-primary:hover {
  background-color: #5eead4;
}

.btn-ghost {
  border: 1px solid var(--color-hero-border);
  color: var(--color-hero-text);
}

.btn-ghost:hover {
  border-color: var(--color-hero-muted);
}

.btn-outline {
  border: 1px solid var(--color-border);
  color: var(--color-text);
}

.btn-outline:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
}

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

.hero {
  position: relative;
  overflow: hidden;
  background-color: var(--color-hero-bg);
  color: var(--color-hero-text);
}

.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    radial-gradient(ellipse 60% 55% at 78% 30%, rgba(20, 184, 166, 0.22), transparent 70%),
    radial-gradient(ellipse 40% 40% at 10% 90%, rgba(14, 165, 233, 0.12), transparent 70%),
    linear-gradient(rgba(148, 163, 184, 0.07) 1px, transparent 1px),
    linear-gradient(90deg, rgba(148, 163, 184, 0.07) 1px, transparent 1px);
  background-size: auto, auto, 44px 44px, 44px 44px;
  mask-image: linear-gradient(to bottom, #000 60%, transparent);
  -webkit-mask-image: linear-gradient(to bottom, #000 60%, transparent);
  pointer-events: none;
}

.hero > * {
  position: relative;
}

.hero-body {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  align-items: center;
  gap: 48px;
  padding-top: clamp(48px, 9vw, 110px);
  padding-bottom: clamp(64px, 10vw, 120px);
}

.eyebrow {
  display: inline-block;
  margin-bottom: 18px;
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-accent);
}

.hero .eyebrow {
  color: var(--color-accent-strong);
}

.hero h1 {
  font-size: clamp(34px, 5.2vw, 56px);
  font-weight: 700;
  line-height: 1.08;
  letter-spacing: -0.03em;
}

.hero h1 em {
  font-style: normal;
  color: var(--color-accent-strong);
}

.hero-lead {
  max-width: 560px;
  margin-top: 22px;
  font-size: clamp(17px, 1.6vw, 19px);
  color: var(--color-hero-muted);
}

.hero-lead strong {
  color: var(--color-hero-text);
  font-weight: 600;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 32px;
}

.terminal {
  border: 1px solid var(--color-hero-border);
  border-radius: var(--radius);
  background-color: rgba(15, 23, 42, 0.75);
  box-shadow: 0 24px 60px rgba(0, 0, 0, 0.45);
  font-family: var(--font-mono);
  font-size: 13.5px;
  line-height: 1.75;
  overflow: hidden;
}

.terminal-bar {
  display: flex;
  gap: 6px;
  padding: 12px 14px;
  border-bottom: 1px solid var(--color-hero-border);
}

.terminal-bar span {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background-color: #334155;
}

.terminal pre {
  padding: 18px 20px 20px;
  font-family: inherit;
  white-space: pre-wrap;
  color: #cbd5e1;
}

.terminal .t-prompt { color: var(--color-accent-strong); }
.terminal .t-key { color: #f1f5f9; font-weight: 600; }
.terminal .t-ok { color: #4ade80; }
.terminal .t-dim { color: #64748b; }

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

.section {
  padding: clamp(64px, 9vw, 104px) 0;
}

.section--surface {
  background-color: var(--color-surface);
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}

.section-head {
  max-width: 680px;
  margin-bottom: 44px;
}

.section-head h2 {
  font-size: clamp(28px, 3.6vw, 38px);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.02em;
}

.section-head p {
  margin-top: 14px;
  font-size: 18px;
  color: var(--color-muted);
}

.section-foot {
  margin-top: 32px;
}

.grid {
  display: grid;
  gap: 20px;
}

.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

.card {
  display: flex;
  flex-direction: column;
  padding: 28px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background-color: var(--color-bg);
  transition: box-shadow var(--transition), transform var(--transition), border-color var(--transition);
}

a.card {
  text-decoration: none;
}

a.card:hover {
  box-shadow: var(--shadow);
  transform: translateY(-2px);
}

.card h3 {
  font-size: 20px;
  font-weight: 650;
  letter-spacing: -0.01em;
  line-height: 1.3;
}

.card p {
  margin-top: 10px;
  color: var(--color-muted);
}

.card-icon {
  display: grid;
  place-items: center;
  width: 44px;
  height: 44px;
  margin-bottom: 20px;
  border-radius: 10px;
  color: var(--tint, var(--color-accent-strong));
  background-color: color-mix(in srgb, var(--tint, var(--color-accent-strong)) 14%, transparent);
}

.card-icon svg {
  width: 22px;
  height: 22px;
}

.tint-cloud { --tint: var(--tint-cloud); }
.tint-ai { --tint: var(--tint-ai); }
.tint-security { --tint: var(--tint-security); }

.check-list {
  list-style: none;
  margin-top: 18px;
  display: grid;
  gap: 9px;
  font-size: 15px;
}

.check-list li {
  position: relative;
  padding-left: 22px;
}

.check-list li::before {
  content: "";
  position: absolute;
  left: 2px;
  top: 0.62em;
  width: 8px;
  height: 8px;
  border-radius: 2px;
  background-color: var(--tint, var(--color-accent-strong));
}

.card .tech-list {
  margin-top: auto;
  padding-top: 22px;
}

/* Industries */

.industry {
  padding: 24px;
}

.industry h3 {
  font-size: 17px;
}

.industry p {
  font-size: 15px;
}

.industry-tag {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-faint);
  margin-bottom: 12px;
}

/* Engagements */

.step-num {
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 600;
  color: var(--color-accent);
  margin-bottom: 14px;
}

.card .card-meta {
  margin-top: auto;
  padding-top: 18px;
  font-size: 14px;
  color: var(--color-faint);
}

/* Case stories */

.case .case-pillar {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--tint, var(--color-accent));
  margin-bottom: 12px;
}

.case dl {
  margin-top: 16px;
  display: grid;
  gap: 10px;
  font-size: 15px;
}

.case dt {
  font-weight: 600;
  color: var(--color-text);
}

.case dd {
  color: var(--color-muted);
}

.read-more {
  margin-top: auto;
  padding-top: 20px;
  font-size: 15px;
  font-weight: 600;
  color: var(--color-accent);
}

/* Principles */

.principles {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 28px 48px;
}

.principle h3 {
  font-size: 18px;
  font-weight: 650;
}

.principle p {
  margin-top: 6px;
  color: var(--color-muted);
}

/* CTA band */

.cta-band {
  background-color: var(--color-hero-bg);
  color: var(--color-hero-text);
  padding: clamp(56px, 8vw, 88px) 0;
}

.cta-band .container {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 28px;
}

.cta-band h2 {
  font-size: clamp(26px, 3.4vw, 36px);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.15;
}

.cta-band p {
  margin-top: 10px;
  color: var(--color-hero-muted);
  max-width: 560px;
}

.cta-band .hero-actions {
  margin-top: 0;
}

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

.site-footer {
  border-top: 1px solid var(--color-border);
  padding: 28px 0;
  font-size: 14px;
  color: var(--color-faint);
}

.site-footer .container {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 12px;
}

.site-footer a {
  text-decoration: none;
  margin-left: 18px;
}

.site-footer a:first-child {
  margin-left: 0;
}

.site-footer a:hover {
  color: var(--color-accent);
}

footer:empty {
  margin-bottom: 10px;
}

/* ---------- Tech tags ---------- */

.tech-list {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin: 10px 0 0 0;
}

.tech {
  display: inline-block;
  padding: 2px 9px;
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 6px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  line-height: 1.6;
  color: var(--color-muted);
}

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

.page-head {
  padding: clamp(40px, 7vw, 80px) 0 clamp(32px, 5vw, 48px);
}

.page-head h1 {
  font-size: clamp(32px, 4.6vw, 48px);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.1;
}

.page-head p {
  max-width: 680px;
  margin-top: 18px;
  font-size: 19px;
  color: var(--color-muted);
}

.page-head p + p {
  margin-top: 12px;
}

.timeline {
  display: grid;
  gap: 20px;
  padding-bottom: clamp(56px, 8vw, 96px);
}

.role {
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: 32px;
  padding: 32px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
}

.role-company {
  font-size: 20px;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.role-title {
  margin-top: 4px;
  color: var(--color-muted);
}

.role-body h3 {
  font-size: 13px;
  font-family: var(--font-mono);
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-faint);
  margin: 22px 0 10px;
}

.role-body h3:first-child {
  margin-top: 0;
}

.role-body p + p {
  margin-top: 12px;
}

.role-body em {
  font-style: normal;
  font-weight: 600;
}

.tasks-list {
  margin-left: 20px;
  display: grid;
  gap: 6px;
}

.tasks-list li::marker {
  color: var(--color-accent-strong);
}

/* ---------- Blog list ---------- */

.section-blog {
  margin: auto;
  max-width: var(--max-width);
  padding: 0 var(--gutter) 64px var(--gutter);
}

.blog-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.blog-list li {
  padding: 22px 24px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background-color: var(--color-bg);
  transition: box-shadow var(--transition), transform var(--transition);
}

.blog-list li:hover {
  box-shadow: var(--shadow);
  transform: translateY(-2px);
}

.blog-list h3 {
  font-size: 19px;
  font-weight: 650;
  line-height: 1.35;
  margin-bottom: 8px;
}

.blog-list h3 a {
  text-decoration: none;
  color: var(--color-text);
  transition: color var(--transition);
}

.blog-list h3 a:hover {
  color: var(--color-accent);
}

.blog-list p {
  color: var(--color-muted);
  margin: 0;
}

/* ---------- Article ---------- */

.article {
  margin: auto;
  max-width: 720px;
  padding: 40px var(--gutter) 64px var(--gutter);
  font-size: 17px;
  line-height: 1.75;
}

.article .back-link {
  display: inline-block;
  margin-bottom: 28px;
  font-size: 14px;
}

.article .back-link a {
  color: var(--color-accent);
  text-decoration: none;
}

.article .back-link a:hover {
  text-decoration: underline;
}

.article h1 {
  font-size: clamp(28px, 4.4vw, 40px);
  font-weight: 700;
  letter-spacing: -0.025em;
  line-height: 1.15;
  margin-bottom: 14px;
}

.article .subtitle {
  font-style: italic;
  color: var(--color-muted);
  margin-bottom: 24px;
}

.article h2 {
  font-size: 23px;
  font-weight: 650;
  letter-spacing: -0.01em;
  margin-top: 40px;
  margin-bottom: 12px;
}

.article p {
  margin-bottom: 16px;
}

.article pre {
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 10px;
  padding: 16px;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.55;
  margin-bottom: 16px;
}

.article blockquote {
  border-left: 3px solid var(--color-accent-strong);
  background-color: var(--color-surface);
  padding: 12px 16px;
  border-radius: 0 10px 10px 0;
  color: var(--color-muted);
  font-style: italic;
  margin-bottom: 16px;
}

.article ul,
.article ol {
  margin-left: 25px;
  margin-bottom: 16px;
}

.article code {
  font-family: var(--font-mono);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  padding: 0.1em 0.35em;
  border-radius: 5px;
  font-size: 0.86em;
}

.article pre code {
  background: none;
  border: 0;
  padding: 0;
  border-radius: 0;
}

.article a {
  color: var(--color-accent);
}

.article hr {
  border: 0;
  border-top: 1px solid var(--color-border);
  margin: 36px 0;
}

.article .article-footer {
  font-style: italic;
  font-size: 15px;
  color: var(--color-faint);
}

/* ---------- Responsive ---------- */

@media (max-width: 960px) {
  .hero-body {
    grid-template-columns: 1fr;
  }

  .grid-3,
  .grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }

  .grid-3 > :last-child:nth-child(odd) {
    grid-column: 1 / -1;
  }
}

@media (max-width: 700px) {
  :root {
    --gutter: 16px;
  }

  .terminal {
    display: none;
  }

  .grid-3,
  .grid-4,
  .principles {
    grid-template-columns: 1fr;
  }

  .role {
    grid-template-columns: 1fr;
    gap: 16px;
    padding: 24px;
  }

  .menu a {
    padding: 6px 9px;
  }

  .card {
    padding: 22px;
  }

  .site-footer a {
    margin-left: 0;
    margin-right: 16px;
  }
}

/* ---------- Contact ---------- */

.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  padding-bottom: clamp(56px, 8vw, 96px);
}

.contact-grid .card--wide {
  grid-column: 1 / -1;
}

.contact-card h2 {
  font-size: 20px;
  font-weight: 650;
  letter-spacing: -0.01em;
}

.contact-email {
  display: inline-block;
  margin-top: 14px;
  font-size: clamp(20px, 2.6vw, 26px);
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--color-accent);
  text-decoration: none;
  overflow-wrap: anywhere;
}

.contact-email:hover {
  text-decoration: underline;
}

.contact-card p a {
  color: var(--color-accent);
}

.contact-card .hero-actions {
  margin-top: 24px;
}

.contact-card .check-list {
  color: var(--color-muted);
}

.contact-card .check-list strong {
  color: var(--color-text);
  font-weight: 600;
}

@media (max-width: 700px) {
  .contact-grid {
    grid-template-columns: 1fr;
  }
}

/* ---------- Language switch (EN / PL) ---------- */

.menu .lang-switch {
  display: flex;
  align-items: center;
  margin-left: 6px;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  overflow: hidden;
  font-family: var(--font-mono);
}

.menu .lang-switch a,
.menu .lang-switch span {
  display: block;
  padding: 5px 9px;
  border-radius: 0;
  font-size: 13px;
  font-weight: 500;
  line-height: 1.4;
}

.menu .lang-switch span[aria-current] {
  background-color: var(--color-accent-soft);
  color: var(--color-accent);
  font-weight: 600;
}

.site-header--dark .menu .lang-switch {
  border-color: var(--color-hero-border);
}

.site-header--dark .menu .lang-switch span[aria-current] {
  background-color: rgba(45, 212, 191, 0.14);
  color: var(--color-accent-strong);
}

/* ---------- Article accessibility ---------- */
/* Visible keyboard focus, and anchored headings that clear the top edge when jumped to. */
.article :is(a, summary, input, [tabindex]):focus-visible { outline: 3px solid var(--color-accent); outline-offset: 4px; }
.article :is(select, button):focus-visible { outline: 3px solid var(--color-accent); outline-offset: 4px; }
.article [id] { scroll-margin-top: 24px; }