/*
 * Kropf Systems — style.css
 * Version: 1.0 | 2026-03-16
 *
 * Struktur:
 * 1. CSS-Variablen
 * 2. Reset & Base
 * 3. Typography
 * 4. Layout & Container
 * 5. Navigation
 * 6. Hero (Home)
 * 7. Hero (Subpage)
 * 8. Sections & Grids
 * 9. Komponenten (Cards, Buttons, Tags)
 * 10. Footer
 * 11. Responsive
 */


/* ============================================================
   1. CSS-VARIABLEN
   ============================================================ */

:root {
  /* Farben */
  --color-primary:      #0d3b66;   /* Dunkelblau — Hauptfarbe */
  --color-primary-dark: #092d50;   /* Hover, aktive Zustände */
  --color-accent:       #dbe5f1;   /* Hellblau — Hintergründe, Karten */
  --color-highlight:    #f4d35e;   /* Gelb — sparsam, CTAs */
  --color-light:        #f6f7fb;   /* Fast-Weiss — Sektionshintergründe */
  --color-dark:         #001d3d;   /* Footer, dunkle Bereiche */
  --color-text:         #0a192f;   /* Fliesstext */
  --color-text-muted:   #617d98;   /* Sekundärtext, Labels */
  --color-border:       #dde3ec;   /* Trennlinien, Karten-Border */
  --color-white:        #ffffff;

  /* Typografie */
  --font-base: "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-size-base: 1rem;
  --line-height-base: 1.7;

  /* Layout */
  --max-width: 1200px;
  --gutter: 1.5rem;

  /* Abstände */
  --space-xs:  0.5rem;
  --space-sm:  1rem;
  --space-md:  2rem;
  --space-lg:  4rem;
  --space-xl:  6rem;

  /* Komponenten */
  --border-radius: 8px;
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.06);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.10);
  --transition: 0.2s ease;
}


/* ============================================================
   2. RESET & BASE
   ============================================================ */

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

:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 3px;
  border-radius: 2px;
}

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-base);
  font-size: var(--font-size-base);
  line-height: var(--line-height-base);
  color: var(--color-text);
  background-color: var(--color-white);
  -webkit-font-smoothing: antialiased;
}

img,
svg {
  display: block;
  max-width: 100%;
  height: auto;
}

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

ul,
ol {
  list-style: none;
}

button {
  font-family: inherit;
  cursor: pointer;
}


/* ============================================================
   3. TYPOGRAFIE
   ============================================================ */

h1, h2, h3, h4 {
  line-height: 1.25;
  font-weight: 700;
  color: var(--color-primary);
}

h1 {
  font-size: clamp(2rem, 4vw + 0.75rem, 3.25rem);
}

h2 {
  font-size: clamp(1.5rem, 2.5vw + 0.5rem, 2.25rem);
  margin-bottom: var(--space-md);
}

h3 {
  font-size: 1.15rem;
  margin-bottom: var(--space-xs);
}

p {
  max-width: 68ch;
  margin-bottom: var(--space-sm);
}

p:last-child {
  margin-bottom: 0;
}

strong {
  font-weight: 600;
}


/* ============================================================
   4. LAYOUT & CONTAINER
   ============================================================ */

.container {
  width: 100%;
  max-width: var(--max-width);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.section {
  padding-block: var(--space-lg);
}

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

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


/* ============================================================
   5. NAVIGATION
   ============================================================ */

.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--color-border);
}

.navbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 72px;
  padding-block: var(--space-sm);
}

/* Logo */
.logo {
  display: flex;
  align-items: center;
  flex-shrink: 0;
}

.logo img {
  height: 52px;
  width: auto;
}

/* Nav Links */
.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

.nav-links a {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--color-text);
  transition: color var(--transition);
  white-space: nowrap;
}

.nav-links a:hover,
.nav-links a:focus {
  color: var(--color-primary);
}

.nav-links li.active a,
.nav-links a.active {
  color: var(--color-primary);
  font-weight: 600;
}

/* Sprach-Toggle */
.nav-lang {
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--color-text-muted);
  border: 1px solid var(--color-border);
  padding: 0.2rem 0.6rem;
  border-radius: 4px;
  transition: color var(--transition), border-color var(--transition);
}

.nav-lang:hover {
  color: var(--color-primary);
  border-color: var(--color-primary);
}

/* Burger */
.burger {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  padding: var(--space-xs);
}

.burger span {
  display: block;
  width: 22px;
  height: 2px;
  background-color: var(--color-text);
  border-radius: 2px;
  transition: transform 0.3s ease, opacity 0.3s ease;
}


/* ============================================================
   6. HERO — HOME
   ============================================================ */

.hero {
  position: relative;
  min-height: 82vh;
  display: flex;
  align-items: center;
  background-image: url("assets/hero-bg.jpg");
  background-image: image-set(
    url("assets/hero-bg.webp") type("image/webp"),
    url("assets/hero-bg.jpg")  type("image/jpeg")
  );
  background-size: cover;
  background-position: center;
  color: var(--color-white);
}

.hero__overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(
    135deg,
    rgba(0, 29, 61, 0.80) 0%,
    rgba(13, 59, 102, 0.65) 100%
  );
}

.hero__content {
  position: relative;
  z-index: 1;
  max-width: 760px;
  padding-block: var(--space-xl);
}

.hero__content h1 {
  color: var(--color-white);
  margin-bottom: var(--space-md);
  hyphens: auto;
}

.hero__content p {
  font-size: 1.15rem;
  color: rgba(255, 255, 255, 0.88);
  margin-bottom: var(--space-md);
  max-width: 56ch;
}


/* ============================================================
   7. HERO — SUBPAGE
   ============================================================ */

.hero-sub {
  background-color: var(--color-primary);
  color: var(--color-white);
  padding-block: var(--space-lg);
}

.hero-sub h1 {
  color: var(--color-white);
  margin-bottom: var(--space-sm);
}

.hero-sub p {
  font-size: 1.1rem;
  color: rgba(255, 255, 255, 0.82);
  max-width: 60ch;
  margin-bottom: 0;
}


/* ============================================================
   8. SECTIONS & GRIDS
   ============================================================ */

/* Dreispaltig — Kernaussagen, Prinzipien */
.grid-3 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--space-md);
  margin-top: var(--space-md);
}

/* Grid ohne oberen Margin */
.grid--flush {
  margin-top: 0;
}

/* Zweispaltig — z.B. Research-Einträge */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(360px, 1fr));
  gap: var(--space-md);
  margin-top: var(--space-md);
}

/* Section-Header (Titel + optionaler Subtext) */
.section-header {
  margin-bottom: var(--space-md);
}

.section-header p {
  color: var(--color-text-muted);
  font-size: 1.05rem;
}

/* Teaser-Link am Ende einer Sektion */
.section-link {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  margin-top: var(--space-md);
  font-weight: 600;
  color: var(--color-primary);
  transition: gap var(--transition);
}

.section-link:hover {
  gap: 0.7rem;
}

.section-link::after {
  content: "→";
}


/* ============================================================
   9. KOMPONENTEN
   ============================================================ */

/* --- Button --- */
.btn {
  display: inline-block;
  padding: 0.75rem 1.75rem;
  border-radius: var(--border-radius);
  font-weight: 600;
  font-size: 0.95rem;
  transition: background-color var(--transition), color var(--transition);
  white-space: nowrap;
}

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

.btn--primary:hover,
.btn--primary:focus {
  background-color: var(--color-highlight);
  color: var(--color-primary);
}

.btn--outline {
  background-color: transparent;
  color: var(--color-white);
  border: 2px solid rgba(255, 255, 255, 0.6);
}

.btn--outline:hover,
.btn--outline:focus {
  border-color: var(--color-white);
  background-color: rgba(255, 255, 255, 0.1);
}

/* Outline auf hellem Hintergrund */
.btn--outline-dark {
  background-color: transparent;
  color: var(--color-primary);
  border: 2px solid var(--color-primary);
}

.btn--outline-dark:hover,
.btn--outline-dark:focus {
  background-color: var(--color-primary);
  color: var(--color-white);
}

/* Button-Gruppe */
.btn-group {
  display: flex;
  gap: var(--space-sm);
  flex-wrap: wrap;
}

/* --- Card --- */
.card {
  background-color: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius);
  padding: var(--space-md);
  transition: transform var(--transition), box-shadow var(--transition);
}

.card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}

.card h3 {
  color: var(--color-primary);
}

.card p {
  color: var(--color-text-muted);
  font-size: 0.95rem;
}

/* --- Card auf hellem Hintergrund (light section) --- */
.card--light {
  background-color: var(--color-light);
  border-color: transparent;
}

/* --- Tag / Label --- */
.tag {
  display: inline-block;
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--color-primary);
  background-color: var(--color-accent);
  padding: 0.2rem 0.65rem;
  border-radius: 4px;
  margin-bottom: var(--space-sm);
}

/* --- Research Entry Heading --- */
.research-entry h2 {
  font-size: 1.5rem;
  margin-bottom: 0.5rem;
}

/* --- Research Entry --- */
.research-entry {
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius);
  padding: var(--space-md);
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.research-entry h3 {
  font-size: 1.3rem;
  color: var(--color-primary);
}

.research-entry p {
  color: var(--color-text);
  font-size: 0.97rem;
}

.research-links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-top: var(--space-xs);
}

.research-links a {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--color-primary);
  border-bottom: 1px solid var(--color-border);
  transition: border-color var(--transition);
  padding-bottom: 1px;
}

.research-links a:hover {
  border-color: var(--color-primary);
}

/* --- Intro Text --- */
.intro-text {
  font-size: 1.1rem;
  max-width: 72ch;
  color: var(--color-text);
}

/* --- Legal Content --- */
.legal-content h2 {
  font-size: 1.15rem;
  margin-top: var(--space-md);
  margin-bottom: var(--space-xs);
  color: var(--color-primary);
}

.legal-content h2:first-child {
  margin-top: 0;
}

.legal-content p,
.legal-content li {
  font-size: 0.95rem;
  color: var(--color-text);
  max-width: 72ch;
}

.legal-content a {
  color: var(--color-primary);
  border-bottom: 1px solid var(--color-border);
  transition: border-color var(--transition);
}

.legal-content a:hover {
  border-color: var(--color-primary);
}

.legal-list {
  list-style: disc;
  padding-left: 1.25rem;
  margin-top: var(--space-xs);
}

.legal-list li {
  margin-bottom: 0.4rem;
}

/* --- Downloads Placeholder --- */
.downloads-placeholder {
  margin-top: var(--space-md);
  padding: var(--space-md);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius);
  background-color: var(--color-light);
  max-width: 640px;
}

.downloads-placeholder p {
  color: var(--color-text-muted);
  font-size: 0.97rem;
}

.downloads-placeholder a {
  color: var(--color-primary);
  border-bottom: 1px solid var(--color-border);
  transition: border-color var(--transition);
}

.downloads-placeholder a:hover {
  border-color: var(--color-primary);
}

/* --- Divider --- */
.divider {
  border: none;
  border-top: 1px solid var(--color-border);
  margin-block: var(--space-lg);
}

/* --- Founder Card --- */
.founder-card {
  max-width: 520px;
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius);
  padding: var(--space-md);
  background-color: var(--color-white);
}

.founder-info h3 {
  font-size: 1.2rem;
  color: var(--color-primary);
  margin-bottom: 0.15rem;
}

.founder-role {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  margin-bottom: var(--space-sm);
}

.founder-links {
  display: flex;
  gap: var(--space-md);
  margin-top: var(--space-sm);
  flex-wrap: wrap;
}

.founder-links a {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--color-primary);
  border-bottom: 1px solid var(--color-border);
  padding-bottom: 1px;
  transition: border-color var(--transition);
}

.founder-links a:hover {
  border-color: var(--color-primary);
}

/* --- Contact Block --- */
.contact-block {
  max-width: 560px;
}

.contact-email {
  display: inline-block;
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--color-primary);
  border-bottom: 2px solid var(--color-accent);
  padding-bottom: 2px;
  transition: border-color var(--transition);
  margin-top: var(--space-sm);
}

.contact-email:hover {
  border-color: var(--color-primary);
}


/* ============================================================
   10. FOOTER
   ============================================================ */

.footer {
  background-color: var(--color-dark);
  color: rgba(255, 255, 255, 0.75);
  padding-block: var(--space-md);
}

.footer__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-sm);
}

.footer p {
  font-size: 0.875rem;
  margin: 0;
  max-width: none;
}

.footer-links {
  display: flex;
  gap: var(--space-md);
}

.footer-links a {
  font-size: 0.875rem;
  color: rgba(255, 255, 255, 0.6);
  transition: color var(--transition);
}

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


/* ============================================================
   11. RESPONSIVE
   ============================================================ */

@media (max-width: 768px) {

  /* Navigation: Mobile */
  .nav-links {
    position: fixed;
    inset: 72px 0 0 auto;
    width: 260px;
    height: 100dvh;
    background-color: var(--color-white);
    flex-direction: column;
    align-items: flex-start;
    padding: var(--space-md);
    gap: var(--space-md);
    transform: translateX(100%);
    transition: transform 0.3s ease;
    box-shadow: -4px 0 20px rgba(0, 0, 0, 0.1);
    z-index: 99;
  }

  .nav-links.open {
    transform: translateX(0);
  }

  .burger {
    display: flex;
  }

  .burger.open span:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
  }

  .burger.open span:nth-child(2) {
    opacity: 0;
  }

  .burger.open span:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
  }

  /* Hero */
  .hero {
    min-height: 70vh;
  }

  .hero__content {
    padding-block: var(--space-lg);
  }

  /* Grids */
  .grid-2 {
    grid-template-columns: 1fr;
  }

  /* Footer */
  .footer__inner {
    flex-direction: column;
    align-items: flex-start;
  }
}

@media (max-width: 480px) {
  :root {
    --gutter: 1rem;
    --space-lg: 3rem;
  }

  .hero {
    min-height: 60vh;
  }
}