/* Header */
#header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background: rgba(255, 255, 255, 0.8);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--gray-200);
  z-index: var(--z-sticky);
  transition: all var(--transition-base);
}

#header.scrolled {
  background: rgba(255, 255, 255, 0.95);
  box-shadow: var(--shadow-sm);
}

#header nav {
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

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

.logo-icon {
  height: 32px;
  width: 32px;
}

.logo-text {
  height: 24px;
  width: auto;
}

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

.nav-link {
  color: var(--gray-700);
  font-size: var(--text-sm);
  font-weight: 500;
  letter-spacing: 0.01em;
  transition: color var(--transition-fast);
  position: relative;
}

.nav-link:hover,
.nav-link.active {
  color: var(--primary);
}

.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 6px;
  padding: 8px;
}

.menu-toggle span {
  width: 24px;
  height: 2px;
  background: var(--gray-800);
  transition: all var(--transition-fast);
}

/* Hero */
.hero {
  /* keine Fullscreen-Höhe mehr */
  min-height: 100vh;
  display: flex;
  align-items: center;
  /* Platz oberhalb: Header + Bildhöhe + Puffer */
  padding: calc(var(--header-height) + 80px) 0 80px;
  position: relative;
  overflow: hidden;
}

.hero-background {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 300px;
  overflow: hidden;
  z-index: 0;
}

.hero-image {
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.6;
}

.hero-background::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 100px;
  background: linear-gradient(to bottom, transparent, var(--color-white));
}

.hero::before {
  content: "";
  position: absolute;
  top: 20%;
  right: -20%;
  width: 80%;
  height: 80%;
  background: radial-gradient(
    circle at center,
    rgba(8, 145, 178, 0.03) 0%,
    transparent 70%
  );
  pointer-events: none;
}

.hero-content {
  position: relative;
  z-index: 1;
}

.hero-label {
  display: inline-block;
  padding: 6px 16px;
  background: var(--gray-100);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-full);
  font-size: var(--text-sm);
  color: var(--gray-600);
  margin-bottom: var(--space-lg);
  font-weight: 500;
}

.hero-title {
  margin-bottom: var(--space-md);
  color: var(--gray-900);
}

.hero-description {
  font-size: var(--text-xl);
  color: var(--gray-600);
  max-width: 640px;
  margin-bottom: var(--space-2xl);
  line-height: 1.6;
}

.hero-actions {
  display: flex;
  gap: var(--space-sm);
  flex-wrap: wrap;
}

.hero-background picture {
  height: 100%;
}

/* Hero picture fix */
.hero-background picture{
  display:block;
  width:100%;
  height:100%;            /* erbt die 300px der .hero-background */
}

.hero-background picture > img.hero-image{
  width:100%;
  height:100%;            /* füllt die 300px */
  object-fit:cover;
  min-width:640px;        /* zeigt die 640er Datei auch <640px Viewport */
}


/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  padding: 14px 32px;
  border-radius: var(--radius-sm);
  font-size: var(--text-sm);
  font-weight: 500;
  text-decoration: none;
  transition: all var(--transition-fast);
  border: none;
  cursor: pointer;
  letter-spacing: 0.02em;
}

.btn-primary {
  background: var(--gray-900);
  color: var(--color-white);
}

.btn-primary:hover {
  background: var(--color-black);
  transform: translateY(-1px);
}

.btn-secondary {
  background: transparent;
  color: var(--gray-900);
  border: 1px solid var(--gray-300);
}

.btn-secondary:hover {
  border-color: var(--gray-900);
  background: var(--gray-50);
}

.btn-block {
  width: 100%;
  justify-content: center;
}

/* Cards */
.tech-card,
.repo-card {
  background: var(--color-white);
  padding: var(--space-2xl);
  position: relative;
  transition: all var(--transition-base);
}

.tech-card:hover,
.repo-card:hover {
  background: var(--gray-50);
}

.tech-card h3,
.repo-card h3 {
  margin-bottom: var(--space-sm);
  color: var(--gray-900);
}

.tech-card p,
.repo-card p {
  color: var(--gray-600);
  margin-bottom: var(--space-md);
  line-height: 1.6;
}

.tech-card-link,
.repo-link {
  color: var(--primary);
  font-weight: 500;
  font-size: var(--text-sm);
  display: inline-flex;
  align-items: center;
  gap: 4px;
  transition: gap var(--transition-fast);
}

.tech-card-link:hover,
.repo-link:hover {
  gap: 8px;
}

.tech-card-link::after,
.repo-link::after {
  content: "→";
}

.repo-links {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

/* Paper Cards */
.paper-card {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: var(--space-lg);
  padding: var(--space-2xl);
  background: var(--color-white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-sm);
  transition: all var(--transition-base);
}

.paper-card:hover {
  border-color: var(--primary);
  box-shadow: 0 4px 20px rgba(8, 145, 178, 0.1);
}

.paper-content h3 {
  color: var(--gray-900);
  margin-bottom: var(--space-xs);
  font-size: var(--text-xl);
}

.paper-subtitle {
  color: var(--primary);
  font-size: var(--text-sm);
  font-weight: 600;
  margin-bottom: var(--space-sm);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.paper-meta {
  display: flex;
  gap: var(--space-md);
  margin-bottom: var(--space-sm);
}

.paper-meta span {
  color: var(--gray-500);
  font-size: var(--text-sm);
}

.paper-description {
  color: var(--gray-600);
  line-height: 1.6;
  margin-bottom: var(--space-sm);
}

.paper-keywords {
  font-size: var(--text-xs);
  color: var(--gray-500);
  font-style: italic;
  margin-top: var(--space-sm);
  padding-top: var(--space-sm);
  border-top: 1px solid var(--gray-200);
}

.paper-availability {
  font-size: var(--text-xs);
  color: var(--gray-500);
  margin-top: var(--space-xs);
}

.paper-links {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
  justify-content: center;
}

.paper-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  padding: 8px 16px;
  background: var(--gray-100);
  color: var(--gray-700);
  text-decoration: none;
  font-size: var(--text-sm);
  font-weight: 500;
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.paper-link i {
  font-size: 14px;
}

.paper-link:hover {
  background: var(--primary);
  color: var(--color-white);
}

/* Stats */
.stat-card {
  background: var(--color-white);
  padding: var(--space-2xl) var(--space-lg);
  text-align: center;
}

.stat-number {
  font-size: var(--text-5xl);
  font-weight: 200;
  color: var(--primary);
  margin-bottom: var(--space-xs);
}

.stat-label {
  color: var(--gray-600);
  font-size: var(--text-sm);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* GitHub Projects */
.github-section {
  background: var(--gray-900);
  color: var(--color-white);
  padding: 80px 0;
  margin: var(--section-padding) 0;
}

.github-section .section-header {
  text-align: left;
}

.github-section .section-label {
  color: var(--primary-light);
}

.github-section .section-title {
  color: var(--color-white);
}

.github-section .section-description {
  color: var(--gray-300);
}

.github-projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: var(--space-lg);
}

.github-project-card {
  background: var(--color-white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-sm);
  transition: all var(--transition-base);
  display: grid;
  grid-template-columns: 180px 1fr;
  min-height: 280px;
  overflow: hidden;
}

.github-project-card:hover {
  border-color: var(--primary);
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.repo-feature {
  margin-top: var(--space-3xl);
  background: var(--color-white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-sm);
  display: grid;
  grid-template-columns: 240px 1fr;
  overflow: hidden;
}

.repo-feature-image {
  background: var(--gray-100);
}

.repo-feature-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.repo-feature-body {
  padding: var(--space-2xl);
  display: flex;
  flex-direction: column;
}

.repo-feature-body h3 {
  color: var(--gray-900);
  font-size: var(--text-lg);
  margin-bottom: var(--space-xs);
}

.repo-feature-subtitle {
  text-transform: uppercase;
  font-size: var(--text-xs);
  font-weight: 600;
  color: var(--primary);
  letter-spacing: 0.05em;
  margin-bottom: var(--space-md);
}

.repo-feature-body p {
  color: var(--gray-600);
  line-height: 1.6;
  margin-bottom: var(--space-lg);
}

.repo-feature-links {
  margin-top: auto;
  display: flex;
  gap: var(--space-xs);
  flex-wrap: wrap;
}

.opensource-featured-image {
  width: 180px;
  height: 100%;
  overflow: hidden;
  background: var(--gray-100);
  clip-path: polygon(0 0, 100% 0, 85% 100%, 0 100%);
}

.opensource-featured-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--transition-slow);
}

.github-project-card:hover .opensource-featured-image img {
  transform: scale(1.05);
}

.opensource-featured-content {
  padding: var(--space-xl);
  display: flex;
  flex-direction: column;
}

.opensource-featured-content h3 {
  color: var(--gray-900);
  font-size: var(--text-base);
  font-weight: 600;
  margin-bottom: var(--space-xs);
  line-height: 1.3;
}

.opensource-featured-subtitle {
  color: var(--primary);
  font-size: var(--text-xs);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-sm);
}

.opensource-featured-content p {
  color: var(--gray-600);
  font-size: var(--text-sm);
  line-height: 1.6;
  margin-bottom: var(--space-md);
  flex: 1;
}

.opensource-featured-links {
  display: flex;
  gap: var(--space-xs);
  flex-wrap: wrap;
  margin-top: auto;
}

.opensource-link-btn {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 6px 12px;
  background: var(--gray-100);
  color: var(--gray-700);
  font-size: var(--text-xs);
  font-weight: 500;
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
  text-decoration: none;
}

.opensource-link-btn i {
  font-size: 12px;
}

.opensource-link-btn:hover {
  background: var(--primary);
  color: var(--color-white);
}

/* Trademark Notice */
.trademark-notice {
  background: var(--gray-100);
  padding: var(--space-2xl) 0;
  border-top: 1px solid var(--gray-200);
}

.trademark-notice h3 {
  color: var(--gray-900);
  font-size: var(--text-xl);
  margin-bottom: var(--space-md);
}

.trademark-notice p {
  color: var(--gray-600);
  line-height: 1.7;
  margin-bottom: var(--space-sm);
}

.trademark-notice strong {
  color: var(--gray-900);
  font-weight: 600;
}

/* Footer */
.footer {
  background: var(--gray-900);
  color: var(--color-white);
  padding: var(--space-3xl) 0 var(--space-lg);
}

.footer-brand {
  max-width: 320px;
}

.footer-logo {
  height: 40px;
  margin-bottom: var(--space-md);
  filter: brightness(0) invert(1);
  opacity: 0.9;
}

.footer-description {
  color: var(--gray-400);
  line-height: 1.7;
  font-size: var(--text-sm);
}

.footer-main-site {
  display: inline-block;
  margin-top: var(--space-md);
  color: var(--primary-light);
  font-size: var(--text-sm);
  font-weight: 500;
  transition: color var(--transition-fast);
}

.footer-main-site:hover {
  color: var(--color-white);
}

.footer-column {
  display: flex;
  flex-direction: column;
}

.footer-title {
  color: var(--color-white);
  font-size: var(--text-sm);
  font-weight: 600;
  margin-bottom: var(--space-md);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.footer-nav {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.footer-nav a {
  color: var(--gray-400);
  font-size: var(--text-sm);
  transition: color var(--transition-fast);
}

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

.footer-bottom {
  padding-top: var(--space-lg);
  border-top: 1px solid var(--gray-800);
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  flex-wrap: wrap;
  gap: var(--space-sm);
}

.footer-copyright,
.footer-trademark {
  color: var(--gray-500);
  font-size: var(--text-xs);
  line-height: 1.6;
}

/* Legal Section */
.legal-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--space-md);
}

.legal-card {
  background: var(--color-white);
  padding: var(--space-lg);
  border-radius: var(--radius-sm);
  border: 1px solid var(--gray-200);
}

.legal-card h3 {
  color: var(--gray-900);
  font-size: var(--text-base);
  margin-bottom: var(--space-sm);
  font-weight: 600;
}

.legal-card p {
  color: var(--gray-600);
  line-height: 1.6;
  font-size: var(--text-sm);
  margin-bottom: var(--space-xs);
}

.legal-card p:last-child {
  margin-bottom: 0;
}

.legal-card strong {
  color: var(--gray-800);
  font-weight: 600;
  font-size: var(--text-sm);
}