/* Reset mặc định */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Arial', sans-serif;
}

body {
  background: #0f0f0f;
  color: #f5f5f5;
  line-height: 1.6;
}

header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px 50px;
  background: #1a1a1a;
  box-shadow: 0 2px 10px rgba(0,0,0,0.4);
  position: sticky;
  top: 0;
  z-index: 10;
}

header img {
  height: 50px;
}

header nav a {
  color: #f5f5f5;
  margin-left: 20px;
  text-decoration: none;
  transition: color 0.3s ease;
}

header nav a:hover {
  color: #ff0055;
}

.hero {
  text-align: center;
  padding: 100px 20px;
  background: linear-gradient(135deg, #111, #222);
}

.hero h1 {
  font-size: 3rem;
  margin-bottom: 20px;
  color: #ff0055;
  letter-spacing: 2px;
}

.hero p {
  max-width: 600px;
  margin: auto;
  font-size: 1.2rem;
  color: #ddd;
}

.btn-demo {
  display: inline-block;
  margin-top: 30px;
  padding: 15px 40px;
  font-size: 1.2rem;
  font-weight: bold;
  border: none;
  border-radius: 50px;
  background: #ff0055;
  color: #fff;
  cursor: pointer;
  transition: transform 0.2s ease, background 0.3s ease;
}

.btn-demo:hover {
  background: #ff3366;
  transform: scale(1.05);
}

footer {
  background: #1a1a1a;
  padding: 30px;
  text-align: center;
  font-size: 0.9rem;
  margin-top: 50px;
}

footer p {
  margin: 5px 0;
  color: #aaa;
}

.socials a {
  margin: 0 10px;
  color: #ff0055;
  text-decoration: none;
  font-weight: bold;
  transition: color 0.3s ease;
}

.socials a:hover {
  color: #fff;
}