body {
    font-family: Arial, sans-serif;
    text-align: center;
    margin: 0;
    padding: 0;
    color: #fff;
}

/* Video nền */
.background-video {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    z-index: -1;
}

.container {
    padding: 20px;
    position: relative;
    z-index: 1;
}

h1 {
    color: #ffd700;
    font-size: 2.5em;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.7);
}

p {
    font-size: 1.2em;
    margin-bottom: 20px;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.7);
}

.chuc-container {
    margin: 20px auto;
    max-width: 500px;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

#chucText {
    padding: 10px;
    font-size: 1.2em;
    border: 2px solid #ffd700;
    border-radius: 5px;
    text-align: center;
    color: #333;
    background-color: #fff;
    outline: none;
}

button {
    padding: 10px 20px;
    font-size: 1.2em;
    color: #fff;
    background-color: #e74c3c;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s;
}

button:hover {
    background-color: #c0392b;
}

.back-button {
    display: inline-block;
    margin-top: 20px;
    padding: 10px 20px;
    color: #fff;
    background-color: #2ecc71;
    text-decoration: none;
    border-radius: 5px;
    font-size: 1.1em;
}

.back-button:hover {
    background-color: #27ae60;
}