:root {
  color-scheme: dark light;
  --font-heading: "Space Grotesk", system-ui, sans-serif;
  --font-body: "Inter", system-ui, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Consolas, monospace;
  --radius-shell: 22px;
  --radius-card: 8px;
  --shadow-soft: 0 24px 80px rgba(0, 0, 0, 0.28);
  --transition: 180ms ease;
}

html[data-theme="dark"] {
  --page: #101722;
  --surface: #172231;
  --surface-2: #202d3d;
  --surface-soft: rgba(255, 255, 255, 0.04);
  --text: #f4f7fa;
  --muted: #aab6c4;
  --muted-2: #7e8b9b;
  --border: rgba(170, 182, 196, 0.2);
  --border-strong: rgba(170, 182, 196, 0.32);
  --teal: #36c6b4;
  --teal-strong: #159e91;
  --amber: #f2a65a;
  --amber-strong: #d9822b;
  --purple: #a78bfa;
  --rose: #e85d88;
  --green: #86a77a;
  --glow: rgba(54, 198, 180, 0.18);
  --card-shadow: 0 18px 44px rgba(0, 0, 0, 0.24);
}

html[data-theme="light"] {
  --page: #f6f3ed;
  --surface: #ffffff;
  --surface-2: #ece6dc;
  --surface-soft: rgba(16, 23, 34, 0.03);
  --text: #101722;
  --muted: #5f6b7a;
  --muted-2: #798391;
  --border: rgba(16, 23, 34, 0.13);
  --border-strong: rgba(16, 23, 34, 0.2);
  --teal: #159e91;
  --teal-strong: #0d8479;
  --amber: #d9822b;
  --amber-strong: #b9681e;
  --purple: #7c5ad6;
  --rose: #d84c7a;
  --green: #6f936a;
  --glow: rgba(21, 158, 145, 0.12);
  --card-shadow: 0 16px 34px rgba(16, 23, 34, 0.08);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-width: 320px;
  background:
    radial-gradient(circle at 24% 0%, var(--glow), transparent 30rem),
    var(--page);
  color: var(--text);
  font-family: var(--font-body);
  line-height: 1.55;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(170, 182, 196, 0.045) 1px, transparent 1px),
    linear-gradient(90deg, rgba(170, 182, 196, 0.045) 1px, transparent 1px);
  background-size: 72px 72px;
  mask-image: linear-gradient(to bottom, rgba(0, 0, 0, 0.75), transparent 62%);
}

a {
  color: inherit;
  text-decoration: none;
}

svg {
  display: block;
}

.skip-link {
  position: fixed;
  left: 16px;
  top: 16px;
  z-index: 20;
  transform: translateY(-160%);
  border-radius: 999px;
  background: var(--teal);
  color: #061316;
  font-weight: 700;
  padding: 10px 14px;
}

.skip-link:focus {
  transform: translateY(0);
}

:focus-visible {
  outline: 3px solid color-mix(in srgb, var(--teal), white 18%);
  outline-offset: 4px;
}

.site-shell {
  width: min(100% - 40px, 1440px);
  margin: 24px auto;
  overflow: hidden;
  border: 1px solid var(--border);
  border-radius: var(--radius-shell);
  background:
    linear-gradient(145deg, rgba(255, 255, 255, 0.035), transparent 38%),
    var(--page);
  box-shadow: var(--shadow-soft);
}

.site-header {
  display: grid;
  grid-template-columns: auto 1fr auto auto auto;
  gap: 14px;
  align-items: center;
  padding: 42px 64px 28px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 15px;
  min-width: max-content;
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: 800;
  letter-spacing: 0;
}

.brand-mark {
  width: 36px;
  height: 36px;
  color: var(--teal);
  filter: drop-shadow(0 0 16px color-mix(in srgb, var(--teal), transparent 55%));
}

.main-nav {
  display: flex;
  justify-content: flex-end;
  align-items: center;
  gap: clamp(14px, 2vw, 36px);
  color: var(--muted);
  font-size: 0.9rem;
}

.main-nav a,
.footer-nav a,
.text-link,
.card-link {
  transition: color var(--transition), border-color var(--transition), transform var(--transition);
}

.main-nav a {
  border-bottom: 1px solid transparent;
  padding: 8px 0 12px;
}

.main-nav a:hover,
.main-nav a[aria-current="page"] {
  border-color: var(--teal);
  color: var(--teal);
}

.theme-toggle {
  display: inline-grid;
  place-items: center;
  width: 42px;
  height: 42px;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--surface-soft);
  color: var(--text);
  cursor: pointer;
}

.theme-toggle:hover {
  border-color: var(--teal);
  color: var(--teal);
}

.theme-icon {
  width: 20px;
  height: 20px;
}

html[data-theme="dark"] .theme-icon-moon,
html[data-theme="light"] .theme-icon-sun {
  display: none;
}

/* ── Language toggle ──────────────────────────────────────────────────────── */
.lang-toggle {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  height: 42px;
  padding: 0 14px;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--surface-soft);
  color: var(--muted);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  cursor: pointer;
  transition: border-color var(--transition);
}

.lang-toggle:hover {
  border-color: var(--teal);
}

.lang-sep {
  opacity: 0.35;
}

html[data-lang="de"] .lang-toggle .lang-de,
html[data-lang="en"] .lang-toggle .lang-en {
  color: var(--text);
  font-weight: 900;
}

/* ── Hamburger / nav-toggle ───────────────────────────────────────────────── */
.nav-toggle {
  display: none;
  place-items: center;
  width: 42px;
  height: 42px;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--surface-soft);
  color: var(--text);
  cursor: pointer;
  transition: border-color var(--transition), color var(--transition);
}

.nav-toggle:hover {
  border-color: var(--teal);
  color: var(--teal);
}

.nav-toggle svg {
  width: 20px;
  height: 20px;
}

.nav-toggle .icon-close { display: none; }
.nav-toggle[aria-expanded="true"] .icon-menu  { display: none; }
.nav-toggle[aria-expanded="true"] .icon-close { display: block; }

.hero {
  display: grid;
  grid-template-columns: minmax(0, 0.95fr) minmax(320px, 1fr);
  gap: clamp(38px, 6vw, 92px);
  align-items: center;
  padding: 48px 64px 58px;
}

.eyebrow {
  margin: 0 0 18px;
  color: var(--teal);
  font-family: var(--font-mono);
  font-size: 0.86rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

h1,
h2,
h3 {
  margin: 0;
  font-family: var(--font-heading);
  letter-spacing: 0;
  line-height: 1.04;
}

h1 {
  max-width: 650px;
  font-size: clamp(3.4rem, 8vw, 6.6rem);
  font-weight: 900;
}

h1 span {
  color: var(--teal);
}

.hero-claim {
  max-width: 720px;
  margin: 16px 0 0;
  font-size: clamp(1.45rem, 2.5vw, 2.25rem);
  line-height: 1.18;
}

.hero-text {
  max-width: 630px;
  margin: 26px 0 0;
  color: var(--muted);
  font-size: 1rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 18px;
  margin-top: 36px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 14px;
  min-height: 48px;
  border: 1px solid transparent;
  border-radius: var(--radius-card);
  padding: 0 22px;
  font-weight: 800;
  font-size: 0.92rem;
  transition: transform var(--transition), border-color var(--transition), background var(--transition), color var(--transition), box-shadow var(--transition);
}

.button:hover {
  transform: translateY(-2px);
}

.button-primary {
  background: linear-gradient(135deg, var(--teal), var(--teal-strong));
  color: #061316;
  box-shadow: 0 12px 30px color-mix(in srgb, var(--teal), transparent 70%);
}

.button-secondary {
  border-color: var(--border-strong);
  background: var(--surface-soft);
  color: var(--text);
}

.button-secondary:hover {
  border-color: var(--teal);
  color: var(--teal);
}

.button-amber {
  border-color: var(--amber);
  color: var(--amber);
  background: color-mix(in srgb, var(--amber), transparent 92%);
}

.button-amber:hover {
  background: color-mix(in srgb, var(--amber), transparent 84%);
}

.hero-visual {
  position: relative;
  min-height: 410px;
  isolation: isolate;
}

.visual-grid {
  position: absolute;
  inset: 10px 0 0;
  z-index: -1;
  background-image: radial-gradient(color-mix(in srgb, var(--teal), transparent 42%) 1px, transparent 1.5px);
  background-size: 18px 18px;
  mask-image: radial-gradient(circle at center, #000 0 52%, transparent 76%);
  opacity: 0.55;
}

.hero-visual svg {
  width: 100%;
  height: auto;
  max-height: 440px;
}

.visual-lines path {
  fill: none;
  stroke: color-mix(in srgb, var(--muted), transparent 50%);
  stroke-width: 1.4;
}

.visual-nodes circle {
  fill: var(--teal);
  filter: drop-shadow(0 0 12px color-mix(in srgb, var(--teal), transparent 40%));
}

.visual-nodes .node-amber {
  fill: var(--amber);
}

.module rect {
  fill: color-mix(in srgb, var(--surface), transparent 12%);
  stroke: var(--border-strong);
  stroke-width: 1.4;
}

.module {
  color: var(--teal);
  filter: drop-shadow(0 18px 28px rgba(0, 0, 0, 0.24));
}

.module-idea {
  color: var(--amber);
}

.section {
  padding: 0 64px 44px;
}

.section-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  border-top: 1px solid var(--border);
  padding-top: 34px;
  margin-bottom: 28px;
}

.section-header h2,
.lab-heading h2,
.about-strip h2,
.contact-card h2,
.footer-nav h2 {
  font-size: clamp(1.3rem, 2vw, 1.75rem);
}

.text-link,
.card-link {
  color: var(--teal);
  font-weight: 800;
  font-size: 0.85rem;
}

.text-link:hover,
.card-link:hover {
  color: var(--amber);
}

.project-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 22px;
}

.project-card {
  display: flex;
  min-height: 250px;
  flex-direction: column;
  align-items: flex-start;
  border: 1px solid var(--border);
  border-radius: var(--radius-card);
  background:
    linear-gradient(145deg, rgba(255, 255, 255, 0.05), transparent 58%),
    var(--surface);
  padding: 28px;
  box-shadow: var(--card-shadow);
}

.card-icon {
  display: grid;
  place-items: center;
  width: 54px;
  height: 54px;
  border-radius: 50%;
  margin-bottom: 22px;
  color: #fff;
  font-size: 0.8rem;
  font-weight: 900;
}

.card-icon svg {
  width: 28px;
  height: 28px;
}

.icon-mqtt,
.icon-tree,
.icon-talbot {
  background: linear-gradient(135deg, var(--teal), var(--teal-strong));
}

.icon-person {
  background: linear-gradient(135deg, var(--rose), #c7478a);
}

.icon-sport {
  background: linear-gradient(135deg, var(--amber), var(--amber-strong));
}

.project-card h3 {
  font-size: 1.15rem;
}

.project-card p {
  min-height: 54px;
  margin: 14px 0 18px;
  color: var(--muted);
  font-size: 0.92rem;
}

.badge {
  display: inline-flex;
  align-items: center;
  min-height: 24px;
  border: 1px solid currentColor;
  border-radius: 5px;
  padding: 0 8px;
  font-family: var(--font-mono);
  font-size: 0.66rem;
  font-weight: 900;
  text-transform: uppercase;
}

.badge-tool {
  color: var(--teal);
}

.badge-web {
  color: var(--purple);
}

.card-link {
  margin-top: auto;
  align-self: flex-end;
}

.lab-panel {
  display: grid;
  grid-template-columns: minmax(210px, 0.32fr) minmax(260px, 0.58fr) minmax(260px, 0.62fr);
  gap: clamp(24px, 4vw, 56px);
  align-items: start;
  margin: 0 64px 42px;
  border: 1px solid var(--border);
  border-radius: var(--radius-card);
  background:
    linear-gradient(145deg, rgba(255, 255, 255, 0.045), transparent 45%),
    var(--surface);
  padding: 34px;
}

.lab-heading {
  display: flex;
  align-items: center;
  gap: 16px;
}

.lab-icon {
  color: var(--amber);
  font-size: 1.7rem;
  line-height: 1;
}

.lab-panel p {
  margin: 0;
  color: var(--muted);
}

.lab-aside {
  display: grid;
  gap: 20px;
  justify-items: start;
}

.lab-aside strong {
  color: var(--teal);
}

.lab-aside .amber {
  color: var(--amber);
}

.about-strip {
  display: grid;
  grid-template-columns: 0.5fr 1fr;
  gap: clamp(24px, 5vw, 72px);
  align-items: center;
  margin: 0 64px 44px;
  border-top: 1px solid var(--border);
  padding-top: 34px;
}

.about-strip p:last-child {
  margin: 0;
  color: var(--muted);
}

.site-footer {
  border-top: 1px solid var(--border);
  padding: 32px 64px 28px;
}

.footer-main {
  display: grid;
  grid-template-columns: minmax(230px, 1.3fr) minmax(120px, 0.62fr) minmax(130px, 0.6fr) minmax(260px, 1fr);
  gap: clamp(28px, 5vw, 76px);
  align-items: start;
}

.footer-brand p {
  max-width: 260px;
  margin: 18px 0 0;
  color: var(--muted);
}

.footer-nav {
  display: grid;
  gap: 9px;
}

.footer-nav h2,
.contact-card h2 {
  font-size: 1rem;
}

.footer-nav a {
  color: var(--muted);
  font-size: 0.92rem;
}

.footer-nav a:hover {
  color: var(--teal);
}

.contact-card {
  border: 1px solid var(--border);
  border-radius: var(--radius-card);
  background: var(--surface-soft);
  padding: 26px;
}

.contact-card p {
  margin: 12px 0 20px;
  color: var(--muted);
  font-size: 0.92rem;
}

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 22px;
  border-top: 1px solid var(--border);
  margin-top: 30px;
  padding-top: 18px;
}

.footer-bottom p {
  margin: 0;
  color: var(--muted);
  font-size: 0.82rem;
}

.social-links {
  display: flex;
  gap: 16px;
  align-items: center;
}

.social-links a {
  color: var(--text);
}

.social-links a:hover {
  color: var(--teal);
}

.social-links svg {
  width: 20px;
  height: 20px;
}

.legal-page {
  max-width: 820px;
  padding: 64px;
}

.legal-page h1 {
  margin: 20px 0 36px;
  font-size: clamp(2.4rem, 6vw, 4.4rem);
}

.legal-page h2 {
  margin: 38px 0 10px;
  font-size: 1.05rem;
  color: var(--teal);
  font-family: var(--font-mono);
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.legal-page p,
.legal-page li {
  color: var(--muted);
  line-height: 1.7;
}

.legal-page ul {
  padding-left: 1.4em;
  margin: 10px 0;
  color: var(--muted);
}

.legal-page ul li {
  margin-bottom: 4px;
}

.legal-page a {
  color: var(--teal);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.legal-page code {
  font-family: var(--font-mono);
  font-size: 0.88em;
  background: var(--surface-soft);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 1px 6px;
}

.legal-page .button {
  margin-top: 40px;
  text-decoration: none;
}

@media (max-width: 1120px) {
  .site-header {
    grid-template-columns: auto 1fr auto auto auto;
  }

  .main-nav {
    grid-column: 1 / -1;
    justify-content: flex-start;
    flex-wrap: wrap;
    order: 3;
  }

  .hero {
    grid-template-columns: 1fr;
  }

  .hero-visual {
    min-height: 320px;
    max-width: 720px;
  }

  .project-grid {
    grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  }

  .lab-panel,
  .about-strip,
  .footer-main {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 760px) {
  .site-shell {
    width: 100%;
    margin: 0;
    border-left: 0;
    border-right: 0;
    border-radius: 0;
  }

  .site-header,
  .hero,
  .section,
  .site-footer,
  .legal-page {
    padding-left: 22px;
    padding-right: 22px;
  }

  .site-header {
    grid-template-columns: auto 1fr auto auto auto;
    padding-top: 20px;
    padding-bottom: 20px;
    gap: 10px;
    position: relative;
  }

  .brand {
    font-size: 1.05rem;
  }

  .brand-mark {
    width: 32px;
    height: 32px;
  }

  .nav-toggle {
    display: inline-grid;
  }

  .main-nav {
    display: none;
    position: absolute;
    top: calc(100% + 4px);
    left: 0;
    right: 0;
    z-index: 10;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 8px 0;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-card);
    box-shadow: var(--card-shadow);
    margin: 0 22px;
  }

  .main-nav.nav-open {
    display: flex;
  }

  .main-nav a {
    padding: 12px 22px;
    border-bottom: none;
    font-size: 0.95rem;
  }

  .main-nav a:hover,
  .main-nav a[aria-current="page"] {
    background: var(--surface-soft);
    border-bottom: none;
  }

  .hero {
    padding-top: 30px;
    padding-bottom: 38px;
  }

  .hero-actions,
  .section-header,
  .footer-bottom {
    align-items: stretch;
    flex-direction: column;
  }

  .button {
    width: 100%;
  }

  .hero-visual {
    min-height: 230px;
    overflow: hidden;
  }

  .hero-visual svg {
    width: 118%;
    transform: translateX(-8%);
  }

  .project-grid,
  .lab-panel,
  .about-strip,
  .footer-main {
    grid-template-columns: 1fr;
  }

  .project-card {
    min-height: 230px;
  }

  .lab-panel,
  .about-strip {
    margin-left: 22px;
    margin-right: 22px;
  }

  .lab-panel {
    padding: 24px;
  }

  .footer-bottom {
    align-items: flex-start;
  }
}

@media (max-width: 430px) {
  h1 {
    font-size: 3rem;
  }

  .main-nav a {
    padding-bottom: 6px;
  }

  .project-card {
    padding: 23px;
  }
}