/* --- HIỆU ỨNG MÀN HÌNH CHỜ (PRELOADER) - NEON ORBIT --- */
#preloader {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: radial-gradient(circle at center, #14141a 0%, #08080a 100%); 
    z-index: 9999;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    transition: opacity 0.5s ease, visibility 0.5s ease;
}

/* Khung chứa vòng xoay */
.loader-spinner {
    width: 65px;
    height: 65px;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* Tạo 2 vòng xoay bằng pseudo-elements */
.loader-spinner::before,
.loader-spinner::after {
    content: "";
    position: absolute;
    border-radius: 50%;
    border: 3px solid transparent;
}

/* Vòng sáng ngoài (Màu Cyan) */
.loader-spinner::before {
    top: 0; left: 0; right: 0; bottom: 0;
    border-top-color: #06b6d4;
    border-bottom-color: #06b6d4;
    animation: spinOrbit 2s linear infinite;
    filter: drop-shadow(0 0 8px rgba(6, 182, 212, 0.8));
}

/* Vòng sáng trong (Màu Tím) */
.loader-spinner::after {
    top: 12px; left: 12px; right: 12px; bottom: 12px;
    border-left-color: #8b5cf6;
    border-right-color: #8b5cf6;
    animation: spinOrbitReverse 1.5s linear infinite;
    filter: drop-shadow(0 0 8px rgba(139, 92, 246, 0.8));
}

/* Hiệu ứng chữ lấp lánh (Gradient Animation) */
.loader-text {
    margin-top: 25px;
    font-size: 0.9rem;
    font-weight: 700;
    letter-spacing: 4px;
    text-transform: uppercase;
    /* Tạo dải màu */
    background: linear-gradient(90deg, #06b6d4, #8b5cf6, #06b6d4);
    background-size: 200% auto;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    animation: gradientText 2s linear infinite;
}

/* --- TẬP HỢP KEYFRAMES --- */
@keyframes spinOrbit { 
    0% { transform: rotate(0deg); } 
    100% { transform: rotate(360deg); } 
}

@keyframes spinOrbitReverse { 
    0% { transform: rotate(360deg); } 
    100% { transform: rotate(0deg); } 
}

@keyframes gradientText {
    0% { background-position: 0% center; }
    100% { background-position: 200% center; }
}

/* Lớp ẩn Preloader (Dùng JS để add class này khi trang load xong) */
.preloader-hidden {
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
}