body {
    margin: 0;
    padding: 0;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: #000000;
    color: #f1f5f9;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    overflow: hidden;
    perspective: 1000px;
}

.login-container {
    position: relative;
    width: 450px;
    max-width: 90vw;
    height: 350px;
    transform-style: preserve-3d;
    transition: transform 0.8s cubic-bezier(0.4, 0, 0.2, 1);
}

.login-container.rotate-horizontal {
    transform: rotateY(180deg);
}

.face {
    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    backface-visibility: hidden;
    -webkit-backface-visibility: hidden;
}

.face-front {
    cursor: pointer;
    z-index: 2;
}

.face-front img {
    width: 220px;
    height: 220px;
    object-fit: contain;
    transition: transform 0.3s ease;
}

.face-front img:hover {
    transform: scale(1.05);
}

.face-back {
    transform: rotateY(180deg);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 0.8rem;
    padding-top: 10px;
    z-index: 1;
}

.btn-login {
    display: inline-block;
    background: transparent;
    color: #555555;
    padding: 0.8rem 2.5rem;
    border-radius: 6px;
    text-decoration: none;
    font-weight: 400;
    font-size: 1.1rem;
    position: relative;
    cursor: pointer;
    letter-spacing: 0.5px;
    transition: all 0.3s ease;
    text-align: center;
    margin-bottom: -5px;
}

.btn-login:hover {
    color: #f1f5f9;
    border: none;
    box-shadow: none;
    text-shadow: 0 0 10px rgba(255, 255, 255, 0.5);
    transform: translateY(-1px);
}

.separator {
    width: 240px;
    height: 1px;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.8), transparent);
    margin: 0.2rem 0;
}

.btn-back {
    background: transparent;
    color: #737373;
    border: none;
    font-size: 1rem;
    cursor: pointer;
    transition: color 0.2s;
    letter-spacing: 0.5px;
}

.btn-back:hover {
    color: #f1f5f9;
}