/* Reset & base */
* {
  box-sizing: border-box;
}
body {
  margin: 0;
  padding: 0;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background-color: var(--bg-color);
  color: var(--text-color);
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  transition: background-color 0.3s, color 0.3s;
}

/* Light and dark mode variables */
:root {
  --bg-color: #f7f7f7;
  --text-color: #333;
  --nav-bg: white;
  --nav-text: #1e90ff;
  --nav-hover: #0f6ddb;
  --card-bg: white;
  --footer-text: #777;
  --button-bg: #1e90ff;
  --button-hover: #0f6ddb;
}
body.dark {
  --bg-color: #121212;
  --text-color: #ddd;
  --nav-bg: #1f1f1f;
  --nav-text: #58a6ff;
  --nav-hover: #82caff;
  --card-bg: #1f1f1f;
  --footer-text: #aaa;
  --button-bg: #58a6ff;
  --button-hover: #1e5bb8;
}

/* Navigation */
nav {
  background: var(--nav-bg);
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
  padding: 15px 30px;
  display: flex;
  gap: 25px;
  font-weight: 600;
  align-items: center;
  justify-content: space-between;
}
nav .links {
  display: flex;
  gap: 25px;
}
nav a {
  color: var(--nav-text);
  text-decoration: none;
  font-size: 1.1rem;
}
nav a:hover {
  text-decoration: underline;
}

/* Dark mode toggle button */
#dark-mode-toggle {
  cursor: pointer;
  background: var(--button-bg);
  color: white;
  border: none;
  border-radius: 6px;
  padding: 8px 14px;
  font-weight: 700;
  font-size: 0.9rem;
  transition: background-color 0.3s ease;
}
#dark-mode-toggle:hover {
  background: var(--button-hover);
}

/* Main container */
main {
  flex-grow: 1;
  max-width: 700px;
  margin: 60px auto 40px;
  background: var(--card-bg);
  padding: 40px;
  border-radius: 10px;
  box-shadow: 0 8px 20px rgba(0,0,0,0.1);
  text-align: center;
  transition: background-color 0.3s, color 0.3s;
}

/* Headings & text */
h1 {
  font-size: 2.8rem;
  margin-bottom: 15px;
  color: var(--nav-text);
}
p {
  font-size: 1.3rem;
  line-height: 1.6;
  margin-bottom: 30px;
}
.highlight {
  color: var(--nav-text);
  font-weight: 700;
}

/* Buttons and links on main */
.main-links {
  display: flex;
  justify-content: center;
  gap: 40px;
  font-size: 1.2rem;
}
.main-links a {
  padding: 12px 25px;
  background-color: var(--button-bg);
  color: white;
  border-radius: 8px;
  transition: background-color 0.3s ease;
  text-decoration: none;
}
.main-links a:hover {
  background-color: var(--button-hover);
}

/* Footer */
footer {
  text-align: center;
  padding: 20px 0;
  color: var(--footer-text);
  font-size: 0.9rem;
  user-select: none;
}

/* Contact form */
form {
  display: flex;
  flex-direction: column;
  gap: 20px;
  max-width: 500px;
  margin: 0 auto;
}
textarea {
  padding: 14px;
  font-size: 1rem;
  border-radius: 6px;
  border: 1px solid #ccc;
  resize: vertical;
  min-height: 120px;
  font-family: inherit;
  transition: border-color 0.3s;
}
textarea:focus {
  border-color: var(--nav-text);
  outline: none;
}
button[type="submit"] {
  background-color: var(--button-bg);
  color: white;
  font-weight: 700;
  border: none;
  padding: 15px;
  border-radius: 6px;
  cursor: pointer;
  transition: background-color 0.3s ease;
  font-size: 1.1rem;
}
button[type="submit"]:hover {
  background-color: var(--button-hover);
}

/* Social links in footer */
.social-links {
  margin-top: 10px;
  display: flex;
  justify-content: center;
  gap: 25px;
}
.social-links a {
  color: var(--footer-text);
  text-decoration: none;
  font-size: 1.5rem;
  transition: color 0.3s;
}
.social-links a:hover {
  color: var(--nav-text);
}

/* Responsive */
@media (max-width: 600px) {
  main {
    margin: 40px 20px 30px;
    padding: 30px 20px;
  }
  nav {
    flex-direction: column;
    gap: 10px;
    align-items: flex-start;
  }
  .main-links {
    flex-direction: column;
  }
  .main-links a {
    padding: 10px 15px;
  }
}