:root {
  --color-bg: #0f172a;
  --color-bg-alt: #0b1120;
  --color-surface: #ffffff;
  --color-surface-alt: #f1f5f9;
  --color-text: #0f172a;
  --color-text-muted: #64748b;
  --color-primary: #2563eb;
  --color-primary-dark: #1d4ed8;
  --color-accent: #f97316;
  --color-border: #e2e8f0;
  --shadow-soft: 0 10px 25px rgba(15, 23, 42, 0.12);
  --radius-lg: 16px;
  --radius-md: 10px;
  --radius-sm: 6px;
  --transition-fast: 0.18s ease-out;
  --max-width: 1120px;
  --font-sans: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI",
    sans-serif;
}

/* Reset & Basics */
*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  color: var(--color-text);
  background: radial-gradient(circle at top left, #1d4ed8 0, #020617 45%);
}
a:link {
 color: #33ccff;
}
a:visited {
 color: #cecece;
}
a:hover {
 color: #336666;
}
a:active {
 color: #339999;
}

/* Layout helpers */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

.section {
  padding: 4.5rem 0;
  background: var(--color-surface);
}

.section-alt {
  background: var(--color-surface-alt);
}

.section-inner {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.section-header {
  max-width: 720px;
}

.section-header h2 {
  font-size: 2rem;
  margin-bottom: 0.5rem;
}

.section-header p {
  margin: 0;
  color: var(--color-text-muted);
  line-height: 1.6;
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  backdrop-filter: blur(16px);
  background: rgba(15, 23, 42, 0.86);
  border-bottom: 1px solid rgba(148, 163, 184, 0.25);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 64px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  color: #e5e7eb;
  font-weight: 600;
}

.logo-mark {
  width: 32px;
  height: 32px;
  border-radius: 999px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 0.8rem;
  color: #0b1120;
  box-shadow: 0 8px 18px rgba(15, 23, 42, 0.4);
}

.logo-text {
  letter-spacing: 0.02em;
}

.main-nav {
  display: flex;
  gap: 1.25rem;
  align-items: center;
}

.main-nav a {
  color: #e5e7eb;
  text-decoration: none;
  font-size: 0.9rem;
  opacity: 0.9;
  transition: opacity var(--transition-fast), color var(--transition-fast);
}

.main-nav a:hover {
  opacity: 1;
  color: #ffffff;
}

.header-cta {
  margin-left: 1rem;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 999px;
  padding: 0.6rem 1.4rem;
  font-size: 0.95rem;
  font-weight: 600;
  border: 1px solid transparent;
  cursor: pointer;
  text-decoration: none;
  transition:
    background-color var(--transition-fast),
    color var(--transition-fast),
    box-shadow var(--transition-fast),
    transform var(--transition-fast),
    border-color var(--transition-fast);
  white-space: nowrap;
}

.btn-primary {
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  color: #0b1120;
  box-shadow: 0 14px 30px rgba(15, 23, 42, 0.35);
}

.btn-primary:hover {
  transform: translateY(-1px);
  box-shadow: 0 18px 40px rgba(15, 23, 42, 0.4);
}

.btn-outline {
  background: transparent;
  border-color: rgba(148, 163, 184, 0.7);
  color: #e5e7eb;
}

.section .btn-outline {
  color: var(--color-primary);
  border-color: rgba(37, 99, 235, 0.4);
}

.section .btn-outline:hover {
  border-color: var(--color-primary);
  background: rgba(37, 99, 235, 0.06);
}

.btn-block {
  width: 100%;
}

/* Hero */
.hero {
  padding: 4.5rem 0 4rem;
  color: #e5e7eb;
}

.hero-inner {
  display: grid;
  grid-template-columns: minmax(0, 3fr) minmax(0, 2.4fr);
  gap: 3.5rem;
  align-items: center;
}

.hero-content h1 {
  font-size: 2.4rem;
  margin: 0 0 0.6rem;
}

.hero-subtitle {
  margin: 0 0 1rem;
  color: #cbd5f5;
  line-height: 1.7;
}

.eyebrow {
  text-transform: uppercase;
  font-size: 0.8rem;
  letter-spacing: 0.14em;
  color: #93c5fd;
  margin-bottom: 0.5rem;
}

.hero-benefits {
  list-style: none;
  padding: 0;
  margin: 0 0 1.4rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.8rem;
}

.hero-benefits li {
  font-size: 0.9rem;
  padding: 0.35rem 0.8rem;
  border-radius: 999px;
  background: rgba(15, 23, 42, 0.55);
  border: 1px solid rgba(148, 163, 184, 0.45);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-bottom: 0.75rem;
}

.hero-note {
  font-size: 0.9rem;
  color: #9ca3af;
}

/* Book hero card */
.hero-aside {
  display: flex;
  justify-content: flex-end;
}

.book-card {
  background: rgba(15, 23, 42, 0.8);
  border-radius: var(--radius-lg);
  padding: 1.2rem;
  border: 1px solid rgba(148, 163, 184, 0.45);
  box-shadow: var(--shadow-soft);
  display: grid;
  grid-template-columns: minmax(0, 1.4fr) minmax(0, 2fr);
  gap: 1rem;
  backdrop-filter: blur(18px);
}

.book-cover-placeholder {
  border-radius: var(--radius-md);
  border: 1px dashed rgba(148, 163, 184, 0.7);
  background: radial-gradient(circle at top, rgba(37, 99, 235, 0.2), transparent);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #9ca3af;
  font-size: 0.8rem;
  text-align: center;
  padding: 0.6rem;
}

.book-cover-placeholder.tall {
  min-height: 260px;
}

.book-meta {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
  font-size: 0.85rem;
  color: #e5e7eb;
}

.book-title {
  font-weight: 600;
}

.book-subtitle {
  color: #cbd5f5;
}

.book-authors,
.book-price {
  color: #9ca3af;
}

.book-hint {
  font-size: 0.75rem;
  color: #9ca3af;
  margin: 0.3rem 0 0;
}

/* Grid & cards */
.grid {
  display: grid;
  gap: 1.5rem;
}

.grid-3 {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.card {
  background: #ffffff;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
  padding: 1.4rem;
  box-shadow: 0 12px 30px rgba(15, 23, 42, 0.04);
}

.section-alt .card {
  background: #ffffff;
}

/* Partner cards */
.card-partner {
  border-top: 3px solid var(--color-primary);
}

.card-partner h3 {
  margin-top: 0;
}

.card h3 {
  margin-top: 0;
  margin-bottom: 0.5rem;
}

.card p {
  margin: 0;
  color: var(--color-text-muted);
  line-height: 1.6;
}

/* Book section */
.book-section {
  display: grid;
  grid-template-columns: minmax(0, 3fr) minmax(0, 2.2fr);
  gap: 2rem;
  align-items: center;
}

.book-section-text {
  max-width: 640px;
}

.book-section-text p {
  color: var(--color-text-muted);
  line-height: 1.7;
}

.feature-list {
  list-style: none;
  padding: 0;
  margin: 1rem 0 1.25rem;
}

.feature-list li {
  position: relative;
  margin-bottom: 0.4rem;
  padding-left: 1.4rem;
  color: var(--color-text-muted);
}

.feature-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.5rem;
  width: 8px;
  height: 8px;
  border-radius: 999px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
}

.book-section-meta {
  font-size: 0.9rem;
  color: var(--color-text);
}

.book-cta-group {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin: 1rem 0;
}

.book-section-note {
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

.book-section-aside {
  display: flex;
  justify-content: flex-end;
}

/* Partner highlight */
.partner-highlight {
  background: #eff6ff;
  border-left: 4px solid var(--color-primary);
  border-radius: var(--radius-md);
  padding: 1.2rem 1.4rem;
  color: #1e293b;
  line-height: 1.7;
}

.partner-cta {
  margin-top: 1.5rem;
  text-align: center;
}

.partner-cta p {
  color: var(--color-text-muted);
  max-width: 720px;
  margin: 0.4rem auto 1rem;
}

/* Autoren */
.authors-section {
  max-width: 760px;
}

.authors-text h2 {
  margin-top: 0;
}

.author + .author {
  margin-top: 1.2rem;
}

.author h3 {
  margin: 0 0 0.3rem;
}

.author p {
  margin: 0;
  color: var(--color-text-muted);
  line-height: 1.7;
}

.quote {
  margin: 1.5rem 0 0;
  padding: 0.8rem 1rem;
  border-left: 3px solid var(--color-accent);
  background: #e5e7eb;
  border-radius: 0 10px 10px 0;
  font-style: italic;
  color: #111827;
}

/* Kontakt */
.contact-section {
  display: grid;
  grid-template-columns: minmax(0, 3fr) minmax(0, 2.5fr);
  gap: 2rem;
  align-items: flex-start;
}

.contact-text p {
  color: var(--color-text-muted);
  line-height: 1.7;
}

.contact-direct {
  font-weight: 500;
}

.contact-direct a {
  color: var(--color-primary);
  text-decoration: none;
}

.contact-direct a:hover {
  text-decoration: underline;
}

.contact-form-wrapper {
  background: #f9fafb;
  border-radius: var(--radius-md);
  padding: 1.5rem;
  border: 1px solid var(--color-border);
}

.contact-form .form-group {
  margin-bottom: 0.9rem;
}

.contact-form label {
  display: block;
  font-size: 0.85rem;
  margin-bottom: 0.3rem;
  color: #334155;
}

.contact-form input,
.contact-form textarea {
  width: 100%;
  border-radius: 10px;
  border: 1px solid var(--color-border);
  padding: 0.55rem 0.7rem;
  font-family: inherit;
  font-size: 0.9rem;
  transition: border-color var(--transition-fast),
              box-shadow var(--transition-fast),
              background-color var(--transition-fast);
}

.contact-form input:focus,
.contact-form textarea:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 1px rgba(37, 99, 235, 0.18);
  background-color: #ffffff;
}

.form-hint {
  margin-top: 0.6rem;
  font-size: 0.8rem;
  color: var(--color-text-muted);
}

/* Footer */
.site-footer {
  background: #020617;
  color: #9ca3af;
  padding: 1.5rem 0;
  font-size: 0.85rem;
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
}

.footer-links {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

.footer-links a {
  color: #9ca3af;
  text-decoration: none;
}

.footer-links a:hover {
  color: #e5e7eb;
}

/* Mobile nav */
.nav-toggle {
  display: none;
  width: 34px;
  height: 28px;
  flex-direction: column;
  justify-content: space-between;
  border: none;
  background: transparent;
  padding: 4px 2px;
  cursor: pointer;
}

.nav-toggle span {
  display: block;
  height: 2px;
  width: 100%;
  background: #e5e7eb;
  border-radius: 999px;
}

.hrefwhite {
    color: white;
}

/* Responsive */
@media (max-width: 960px) {
  .hero-inner {
    grid-template-columns: minmax(0, 1fr);
  }

  .hero-aside {
    order: -1;
    justify-content: flex-start;
  }

  .book-card {
    grid-template-columns: minmax(0, 1fr);
  }

  .book-section {
    grid-template-columns: minmax(0, 1fr);
  }

  .book-section-aside {
    justify-content: flex-start;
  }

  .contact-section {
    grid-template-columns: minmax(0, 1fr);
  }

  .grid-3 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 720px) {
  .header-cta {
    display: none;
  }

  .main-nav {
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    flex-direction: column;
    background: rgba(15, 23, 42, 0.98);
    padding: 0.75rem 1.5rem 1rem;
    border-bottom: 1px solid rgba(148, 163, 184, 0.4);
    transform: translateY(-120%);
    opacity: 0;
    pointer-events: none;
    transition: transform var(--transition-fast), opacity var(--transition-fast);
  }

  .main-nav.open {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }

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

  .hero {
    padding-top: 3.5rem;
  }

  .hero-content h1 {
    font-size: 2rem;
  }

  .grid-3 {
    grid-template-columns: minmax(0, 1fr);
  }

  .section {
    padding: 3.5rem 0;
  }

  .footer-inner {
    flex-direction: column;
    align-items: flex-start;
  }
}