/* ======================================
   CSS Reset & Variables
   ====================================== */

:root {
  /* Color Palette */
  --color-bg: #f9fafb;
  --color-surface: #ffffff;
  --color-border: #d1d5db;
  --color-text: #111827;
  --color-accent: #2563eb;
  --color-accent-hover: #1e40af;

  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 2rem;
  --spacing-xl: 4rem;

  /* Typography */
  --font-family-base: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  --font-size-base: 16px;
  --line-height-base: 1.5;

  /* Layout */
  --max-width-content: 1200px;
  --transition-base: 0.2s ease-in-out;

  /* Breakpoints */
  --bp-sm: 640px;
  --bp-md: 768px;
  --bp-lg: 1024px;
  --bp-xl: 1280px;
}

/* Reset Styles */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html, body {
  width: 100%;
  height: 100%;
}

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

h1, h2, h3, h4, h5, h6 {
  font-weight: 600;
  line-height: 1.25;
  color: var(--color-text);
}

a {
  color: var(--color-accent);
  text-decoration: none;
  transition: color var(--transition-base);
}

a:hover, a:focus {
  color: var(--color-accent-hover);
}

ul, ol {
  list-style: none;
}

button {
  background: none;
  border: none;
  cursor: pointer;
  font: inherit;
  color: inherit;
}

/* ======================================
   Application Shell Layout
   ====================================== */

.app-shell {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.app-header {
  background-color: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  padding: var(--spacing-md);
  text-align: center;
}

.app-header h1 {
  font-size: 1.5rem;
  margin-bottom: var(--spacing-sm);
}

main {
  flex: 1;
  max-width: var(--max-width-content);
  margin: 0 auto;
  padding: var(--spacing-lg) var(--spacing-md);
  width: 100%;
}

.app-footer {
  background-color: var(--color-surface);
  border-top: 1px solid var(--color-border);
  text-align: center;
  padding: var(--spacing-sm);
  font-size: 0.875rem;
}

.app-footer p {
  color: var(--color-text);
  opacity: 0.8;
}

/* Responsive typography and spacing */
@media (min-width: 640px) {
  .app-header h1 {
    font-size: 2rem;
  }
  main {
    padding: var(--spacing-xl) var(--spacing-lg);
  }
}

/* Footer copyright */
.app-footer::after {
  content: "© 2026 Donau2Space.de";
  display: block;
  margin-top: var(--spacing-xs);
  font-size: 0.75rem;
  color: var(--color-text);
  opacity: 0.6;
}