body { font-family: 'Poppins', sans-serif; background: linear-gradient(135deg, #f0f9ff 0%, #e0f2fe 100%); min-height: 100vh; display: flex; align-items: center; justify-content: center; padding: 20px; }
        .reg-card { background: #ffffff; border-radius: 24px; width: 100%; max-width: 500px; padding: 40px; box-shadow: 0 15px 35px rgba(0,0,0,0.05); }
        .form-control { border-radius: 12px; padding: 12px 15px; border: 1px solid #e2e8f0; background-color: #f8fafc; transition: 0.3s; }
        .btn-reg { background: #0ea5e9; border: none; border-radius: 12px; padding: 14px; font-weight: 600; color: white; transition: 0.3s; }
        .btn-reg:hover:not(:disabled) { background: #0284c7; transform: translateY(-2px); box-shadow: 0 5px 15px rgba(14, 165, 233, 0.3); }
        .btn-reg:disabled { background: #94a3b8; cursor: not-allowed; }
        
        /* Input Validation Styles */
        .is-invalid { border-color: #ef4444 !important; background-color: #fef2f2 !important; }
        .is-valid { border-color: #22c55e !important; background-color: #f0fdf4 !important; }

        /* DESIGNED BACK TO LOGIN BUTTON */
.btn-back-login {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 5px 15px 5px 5px; /* Compact padding */
    background: #f8fafc; 
    color: #64748b; 
    text-decoration: none;
    border-radius: 50px; 
    font-size: 0.8rem;
    font-weight: 600;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    border: 1px solid #e2e8f0;
}

.btn-back-login .icon-circle {
    width: 26px;
    height: 26px;
    background: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
    transition: all 0.3s ease;
}

.btn-back-login i {
    font-size: 0.8rem;
    color: #0ea5e9; 
}

/* HOVER ANIMATION */
.btn-back-login:hover {
    background: #f1f5f9;
    color: #0ea5e9;
    transform: translateX(-5px); 
    box-shadow: 0 4px 12px rgba(0,0,0,0.05);
}

.btn-back-login:hover .icon-circle {
    background: #0ea5e9; 
}

.btn-back-login:hover i {
    color: white; 
}

/* Para hindi mag-overlap sa mobile */
@media (max-width: 480px) {
    .reg-card {
        padding: 30px 20px;
    }
    .btn-back-login {
        font-size: 0.75rem;
    }
}