@import url('https://fonts.googleapis.com/css?family=Roboto:300,400,700&display=swap');

:root {
  --bg-color: #f4f4f4;
  --text-color: #000;
  --header-bg: #fff;
  --button-bg: #333;
  --button-hover: #555;
}
body.dark-mode {
  --bg-color: #121212;
  --text-color: #eee;
  --header-bg: #1e1e1e;
  --button-bg: #444;
  --button-hover: #666;
}
html, body {
  height: 100%;
}
body {
  font-family: 'Roboto', sans-serif;
  margin: 0;
  padding: 0;
  background-color: var(--bg-color);
  color: var(--text-color);
  display: flex;
  flex-direction: column;
  align-items: center;
  min-height: 100vh;
  transition: background-color 0.3s, color 0.3s;
}
header {
  text-align: center;
  padding: 2rem 1rem 1rem 1rem;
  background-color: var(--header-bg);
  width: 100%;
  box-shadow: 0 2px 5px rgba(0,0,0,0.07);
}
header img {
  width: 150px;
  height: 150px;
  border-radius: 50%;
  border: 3px solid #444;
  object-fit: cover;
  margin-bottom: 1rem;
}
header h1 {
  margin: 0;
  font-size: 2rem;
}
header p {
  font-style: italic;
}
#toggleTheme {
  margin-top: 1rem;
  padding: 0.7rem 1.5rem;
  font-size: 1rem;
  border: none;
  border-radius: 5px;
  background-color: var(--button-bg);
  color: white;
  cursor: pointer;
  transition: background-color 0.3s;
}
#toggleTheme:hover {
  background-color: var(--button-hover);
}
.nav-buttons {
  margin: 2rem 0 1rem 0;
  text-align: center;
}
.nav-buttons a {
  margin: 0.5rem;
  padding: 0.7rem 1.5rem;
  font-size: 1rem;
  border: none;
  border-radius: 5px;
  background-color: var(--button-bg);
  color: white;
  text-decoration: none;
  cursor: pointer;
  transition: background-color 0.3s;
  display: inline-block;
}
.nav-buttons a:hover {
  background-color: var(--button-hover);
}
.nav-buttons a.active {
  background-color: #333;
  color: #fff;
  font-weight: bold;
  border: 2px solid #333;
}
body.dark-mode .nav-buttons a.active {
  background-color: #444;
  border-color: #444;
  color: #fff;
}
main {
  max-width: 800px;
  width: 90%;
  background-color: var(--header-bg);
  padding: 2rem;
  margin-top: 1rem;
  box-shadow: 0 2px 5px rgba(0,0,0,0.07);
  border-radius: 8px;
  flex: 1;
}
main a, main a:visited, main a:active {
  color: var(--text-color);
  text-decoration: underline;
  font-weight: bold;
}
footer {
  width: 100%;
  padding: 1rem 0;
  background-color: var(--header-bg);
  text-align: center;
  box-shadow: 0 -2px 5px rgba(0,0,0,0.07);
  margin-top: 2rem;
}
.social-icons {
  display: inline-flex;
  gap: 1.5rem;
  margin-bottom: 0.5rem;
}
.social-icons a {
  color: var(--text-color);
  transition: color 0.3s;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}
.social-icons a:hover {
  color: #0077b5;
}
body.dark-mode footer {
  background-color: var(--header-bg);
}
body.dark-mode .social-icons a:hover {
  color: #1da1f2;
}
footer p {
  font-size: 0.9rem;
  color: var(--text-color);
  margin: 0;
}