:root {
  --bg: #fff;
  --text: #111;
  --accent: #000;
  --light: #f4f4f4;
}

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

html, body {
  height: 100%;
  scroll-behavior: smooth;
}

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background-color: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

header {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 80vh;
  background:
    linear-gradient(rgba(0,0,0,0.4), rgba(0,0,0,0.4)),
    url('https://images.unsplash.com/photo-1648866891956-c629929382da?q=80&w=4144&auto=format&fit=crop&ixlib=rb-4.1.0&ixid=M3wxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8fA%3D%3D') center/cover no-repeat;
  color: white;
  text-align: center;
  padding: 20px;
}

header h1 {
  font-size: 2.8rem;
  max-width: 800px;
}

nav {
  position: sticky;
  top: 0;
  z-index: 999;
  display: flex;
  justify-content: center;
  gap: 2rem;
  padding: 1rem 2rem;
  background: var(--bg);
  border-bottom: 1px solid #eaeaea;
  box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

nav a {
  text-decoration: none;
  color: var(--text);
  font-weight: 500;
  padding: 0.3rem 0.5rem;
  transition: color 0.3s ease;
}

nav a:hover,
nav a:focus {
  color: var(--accent);
  outline: none;
}

section {
  padding: 4rem 2rem;
  max-width: 900px;
  margin: auto;
}

section h2 {
  font-size: 1.8rem;
  margin-bottom: 1rem;
}

section p {
  margin-bottom: 1rem;
}

form {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  margin-top: 2rem;
}

input,
textarea {
  padding: 1rem;
  border: 1px solid #ddd;
  border-radius: 6px;
  font-size: 1rem;
}

button {
  padding: 1rem;
  background: var(--accent);
  color: white;
  border: none;
  border-radius: 6px;
  font-size: 1rem;
  cursor: pointer;
}

button:hover {
  background: #222;
}

footer {
  text-align: center;
  padding: 2rem;
  background: var(--light);
  font-size: 0.9rem;
}

.footer-button {
  display: inline-block;
  margin-top: 1rem;
  padding: 0.6rem 1.2rem;
  background: var(--accent);
  color: #fff;
  text-decoration: none;
  border-radius: 6px;
  font-size: 0.9rem;
  transition: background 0.3s ease;
}

.footer-button:hover {
  background: #222;
}

/* 🌙 Dark Mode */
.dark {
  --bg: #111;
  --text: #eee;
  --accent: #fff;
  --light: #222;
}

/* 🔁 Responsive Verhalten */
@media (max-width: 768px) {
  header h1 {
    font-size: 2rem;
  }

  nav {
    flex-direction: column;
    gap: 1rem;
    text-align: center;
    padding: 1rem;
  }

  section {
    padding: 2rem 1rem;
  }

  form {
    gap: 0.8rem;
  }

  input, textarea {
    font-size: 0.95rem;
  }

  button {
    font-size: 0.95rem;
  }

  .footer-button {
    font-size: 0.85rem;
    padding: 0.5rem 1rem;
  }
}