/* Cài đặt chung */
html, body {
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100%;
    font-family: 'Poppins', sans-serif;
    overflow: hidden; /* Ẩn thanh cuộn do ảnh động */
}
body {
    background: linear-gradient(135deg, #2a002a, #000000, #2a002a); /* Tím đậm - Đen - Tím đậm */
    color: white;
    position: relative;
}
/* Hiệu ứng nền (Ánh sáng mờ) */
.background-effect {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 0;
    background: radial-gradient(circle at center, rgba(255, 105, 180, 0.1) 0%, transparent 70%);
    animation: pulseBackground 15s infinite alternate;
}
@keyframes pulseBackground {
    0% { transform: scale(1); opacity: 0.8; }
    100% { transform: scale(1.1); opacity: 1; }
}
/* Container cho ảnh động */
#animation-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 1;
    pointer-events: none;
    filter: blur(0.5px); 
}
/* Lớp nội dung chính */
.main-container {
    position: relative;
    z-index: 2;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 20px;
    box-sizing: border-box;
    text-shadow: 0 0 10px rgba(255,255,255,0.5);
}
/* Tiêu đề lãng mạn */
.romantic-title {
    font-family: 'Dancing Script', cursive;
    font-size: 4rem;
    color: #ffb6c1; /* Hồng nhạt */
    margin-bottom: 10px;
    text-shadow: 0 0 20px rgba(255, 105, 180, 0.7);
    text-align: center;
}
.romantic-subtitle {
    font-size: 1.2rem;
    color: rgba(255, 255, 255, 0.8);
    margin-bottom: 40px;
    text-align: center;
}
.button-container {
    display: flex;
    flex-direction: row;
    gap: 25px;
}
/* Nút bấm */
.btn {
    display: inline-block;
    padding: 15px 35px;
    font-size: 1.2rem;
    font-weight: 700;
    text-decoration: none;
    color: white;
    border-radius: 50px;
    border: none;
    cursor: pointer;
    transition: transform 0.3s ease, box-shadow 0.3s ease, background 0.3s ease;
    background: linear-gradient(45deg, #ff69b4, #ff007f);
    box-shadow: 0 0 15px rgba(255, 105, 180, 0.7), 
                0 0 25px rgba(255, 0, 127, 0.5);
}
.btn:hover {
    transform: scale(1.05);
    box-shadow: 0 0 30px rgba(255, 105, 180, 1), 
                0 0 50px rgba(255, 0, 127, 0.8);
    background: linear-gradient(45deg, #ff8fd0, #ff3399);
}
/* Ảnh bay */
.floating-image {
    position: absolute;
    bottom: -150px;
    width: 80px;
    height: 80px;
    object-fit: cover;
    border-radius: 50%;
    opacity: 0;
    animation: floatUp 10s linear infinite;
    box-shadow: 0 0 10px rgba(255, 105, 180, 0.3); 
    border: 1px solid rgba(255, 105, 180, 0.2);
}
/* Keyframe cho ảnh bay */
@keyframes floatUp {
    0%   { transform: translateY(0) rotate(0deg); opacity: 0; }
    10%  { opacity: 0.7; }
    50%  { opacity: 0.8; transform: translateY(-50vh) rotate(360deg); }
    90%  { opacity: 0.7; }
    100% { transform: translateY(-120vh) rotate(720deg); opacity: 0; }
}
/* Responsive cho Mobile */
@media (max-width: 600px) {
    .romantic-title { font-size: 2.5rem; }
    .romantic-subtitle { font-size: 1rem; }
    .button-container { flex-direction: column; width: 90%; gap: 20px; }
    .btn { width: 100%; padding: 20px 0; text-align: center; font-size: 1.1rem; box-sizing: border-box; }
    .floating-image { width: 50px; height: 50px; }
}