diff --git a/data_visualization/css/base.css b/data_visualization/css/base.css
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+++ b/data_visualization/css/base.css
@@ -0,0 +1,90 @@
+:root {
+  /* Farbvariablen */
+  --color-bg-dark: #0d1117;
+  --color-bg-light: #161b22;
+  --color-text-primary: #f0f6fc;
+  --color-text-secondary: #8b949e;
+  --color-accent: #58a6ff;
+
+  /* Typografie */
+  --font-family-base: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
+  --font-size-base: 16px;
+  --font-size-sm: 0.875rem;
+  --font-size-lg: 1.125rem;
+
+  /* Abstände */
+  --spacing-xs: 0.25rem;
+  --spacing-sm: 0.5rem;
+  --spacing-md: 1rem;
+  --spacing-lg: 2rem;
+  --spacing-xl: 4rem;
+
+  /* Layout */
+  --max-content-width: 1200px;
+}
+
+/* Reset und Grundstruktur */
+html, body {
+  margin: 0;
+  padding: 0;
+  font-family: var(--font-family-base);
+  font-size: var(--font-size-base);
+  background-color: var(--color-bg-dark);
+  color: var(--color-text-primary);
+  height: 100%;
+  min-height: 100%;
+}
+
+body {
+  display: flex;
+  flex-direction: column;
+  align-items: stretch;
+  line-height: 1.5;
+  -webkit-font-smoothing: antialiased;
+  -moz-osx-font-smoothing: grayscale;
+}
+
+/* App Layout */
+.app-header {
+  background-color: var(--color-bg-light);
+  padding: var(--spacing-md);
+  text-align: center;
+  border-bottom: 1px solid var(--color-text-secondary);
+}
+
+.app-main {
+  flex: 1;
+  width: 100%;
+  max-width: var(--max-content-width);
+  margin: 0 auto;
+  padding: var(--spacing-lg) var(--spacing-md);
+  background-color: var(--color-bg-dark);
+}
+
+.app-footer {
+  background-color: var(--color-bg-light);
+  color: var(--color-text-secondary);
+  text-align: center;
+  padding: var(--spacing-sm) var(--spacing-md);
+  border-top: 1px solid var(--color-text-secondary);
+  font-size: var(--font-size-sm);
+}
+
+.app-footer::after {
+  content: "© 2026 Donau2Space.de";
+  display: block;
+  margin-top: var(--spacing-xs);
+}
+
+/* Responsives Verhalten */
+@media (min-width: 640px) {
+  .app-main {
+    padding: var(--spacing-xl) var(--spacing-lg);
+  }
+}
+
+@media (min-width: 1024px) {
+  body {
+    font-size: 1rem;
+  }
+}
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