:root {
  --bg: #1A2A3A;
  --bg-dark: #0B1A2A;
  --text: #EDEDED;
  --muted: #4A5A6A;
  --hover: #2A3A4A;
  --accent: #007BFF;
  --accent-hover: #0056b3;
}

* {
  box-sizing: border-box;
}

html, body {
  height: 100%;
  margin: 0;
}

body {
  background-color: var(--bg);
  font-family: 'Roboto', sans-serif;
  color: var(--text);
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

header {
  background-color: var(--bg-dark);
  padding: 16px 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo img {
  width: 200px;
  height: auto;
}

nav[aria-label="Hauptnavigation"] a {
  color: #fff;
  text-decoration: none;
  padding: 10px 16px;
  border-radius: 6px;
  transition: background-color .2s ease;
}

nav[aria-label="Hauptnavigation"] a:hover,
nav[aria-label="Hauptnavigation"] a:focus {
  background-color: var(--hover);
  outline: none;
}

main.center-content {
  text-align: center;
  margin: 0 auto;
  padding: 40px 16px;
  max-width: 900px;
  width: 100%;
}

.chat-button {
  display: inline-flex;
  align-items: center;
  gap: .5rem;
  background-color: var(--accent);
  color: #fff;
  border: none;
  padding: 12px 24px;
  border-radius: 8px;
  font-size: 18px;
  text-decoration: none;
  cursor: pointer;
  transition: background-color .2s ease, transform .05s ease;
}

.chat-button:hover,
.chat-button:focus {
  background-color: var(--accent-hover);
  outline: 3px solid #fff;
  outline-offset: 2px;
}

.chat-button:active {
  transform: translateY(1px);
}

footer {
  background-color: var(--bg-dark);
  text-align: center;
  padding: 20px;
  margin-top: auto;
}

.footer-links {
  margin-bottom: 8px;
}

.footer-links a {
  color: #fff;
  text-decoration: none;
  margin: 0 10px;
}

.footer-links a:hover,
.footer-links a:focus {
  color: var(--muted);
  text-decoration: underline;
}

h1 {
  margin: 0 0 8px;
  font-size: 2rem;
}

h2 {
  margin: 8px 0 16px;
  font-weight: 400;
  color: #cfd8e3;
}

h3, h4 {
  margin-top: 24px;
}