/* Base */
:root {
  --accent: #0073e6;
  --accent-dark: #005bb5;
  --text: #333;
  --card-bg: #ffffff;
  --page-bg: #f7f8fa;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
}

body {
  font-family: system-ui, -apple-system, Segoe UI, Roboto, sans-serif;
  color: var(--text);
  line-height: 1.6;
  background: var(--page-bg);
  text-align: center;
}

/* Layout containers */
.container {
  max-width: 800px;
  margin: 0 auto;
  padding: 24px 20px;
}

header h1 { margin: 0 0 8px; }

.profile { margin-top: 8px; }

/* Card */
.card {
  background: var(--card-bg);
  border-radius: 12px;
  padding: 28px 20px;
  margin-top: 20px;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.06);
}

.card h2 { margin-top: 0; }

/* Profile image */
.profile-img {
  width: 180px;
  height: 180px;
  border-radius: 50%;
  object-fit: cover;
  border: 3px solid var(--accent);
  box-shadow: 0 4px 12px rgba(0,0,0,0.15);
  transition: transform 0.3s ease;
}

.profile-img:hover { transform: scale(1.03); }

/* Navigation list styled as buttons */
.nav-list {
  list-style: none;       /* remove numbers */
  padding: 0;
  margin: 22px 0 18px;
}

.nav-list li {
  display: inline-block;  /* horizontal row */
  margin: 8px;
}

.nav-list a {
  display: inline-block;
  text-decoration: none;
  background: var(--accent);
  color: #fff;
  padding: 10px 18px;
  border-radius: 8px;
  font-weight: 600;
  transition: background 0.25s ease, transform 0.2s ease, box-shadow 0.25s ease;
  box-shadow: 0 4px 10px rgba(0, 115, 230, 0.25);
}

.nav-list a:hover {
  background: var(--accent-dark);
  transform: translateY(-2px);
}

/* Demo button + message */
button#btn {
  padding: 10px 18px;
  font-size: 16px;
  border: none;
  border-radius: 8px;
  background: #6600FF;
  color: #fff;
  cursor: pointer;
  transition: background 0.25s ease;
}

button#btn:hover { background: #555; }

#msg { min-height: 24px; margin-top: 10px; }

/* Footer */
footer small { color: #666; }

/* Responsive tweaks */
@media (max-width: 520px) {
  .nav-list li { display: block; }
  .nav-list a { width: 100%; }
  .profile-img { width: 150px; height: 150px; }
}