html, body {
    height: 100%;
}

body {
    min-height: 100%;
    display: flex;
    background-color: #f8fafc;
    background-image: 
        radial-gradient(at 0% 0%, rgba(14, 165, 233, 0.45) 0px, transparent 50%), 
        radial-gradient(at 100% 0%, rgba(99, 102, 241, 0.35) 0px, transparent 50%), 
        radial-gradient(at 100% 100%, rgba(56, 189, 248, 0.45) 0px, transparent 50%), 
        radial-gradient(at 0% 100%, rgba(203, 213, 225, 0.35) 0px, transparent 50%);
    background-repeat: no-repeat;
    background-attachment: fixed;
}

.form-signin {
    width: 100%;
    max-width: 400px;
    padding: 15px;
    margin: auto;
    text-align: center;
}

.form-signin .card {
    background: rgba(255, 255, 255, 0.75);
    backdrop-filter: blur(20px);
    border-radius: 24px;
    border: 1px solid rgba(255, 255, 255, 0.8);
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.02), 0 10px 30px rgba(0, 0, 0, 0.05), inset 0 0 0 1px rgba(255, 255, 255, 0.5);
    padding-left: 30px !important;
    padding-right: 30px !important;
}

.divider {
    display: flex;
    align-items: center;
    color: #9ca3af;
    font-size: 14px;
}
.divider::before, .divider::after {
    content: "";
    flex: 1;
    border-bottom: 1px solid rgba(0,0,0,0.1);
}
.divider span {
    padding: 0 10px;
}

.select_custom {
    background-color: rgba(255, 255, 255, 0.6);
    border-radius: 7px;
    padding-left: 35px; 
    padding-right: 1.25rem;
    background-position: right .5rem center;
    background-size: 10px;
}

.btn-alt {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    width: 100%;
    padding: 10px;
    background: transparent;
    border: 1px dashed #cbd5e1; /* Viền nét đứt nhẹ nhàng */
    border-radius: 12px;
    color: #4b5563;
    font-size: 14px;
    font-weight: 500;
    text-decoration: none;
    transition: all 0.2s;
}

.btn-alt:hover {
    border-color: #3b82f6;
    color: #3b82f6;
    background-color: rgba(59, 130, 246, 0.05);
}