body, html {
    height: 100%;
    margin: 0;
    font-family: Arial, sans-serif;
    background: linear-gradient(135deg, #1e3c72 0%, #ffffff76 100%); /* Màu nền đậm sắc hơn */
}

.container {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100%;
}

.login-container {
    background-color: rgba(255, 255, 255, 0.95);
    border-radius: 12px;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
    padding: 40px;
    width: 350px;
}

.login-header {
    text-align: center;
    margin-bottom: 30px;
}

.logo {
    width: 150px; /* Tăng kích thước logo */
    margin-bottom: 20px;
    filter: drop-shadow(0 4px 6px rgba(0, 0, 0, 0.1)); /* Thêm đổ bóng cho logo */
    transition: transform 0.3s ease;
}

.logo:hover {
    transform: scale(1.05); /* Hiệu ứng phóng to nhẹ khi hover */
}

h2 {
    color: #1e3c72; /* Màu chữ phù hợp với màu nền */
    font-weight: 600;
    margin: 0;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.input-group {
    position: relative;
    margin-bottom: 25px;
}

.input-group input {
    width: 100%;
    padding: 10px 0;
    font-size: 16px;
    color: #333;
    border: none;
    border-bottom: 2px solid #ddd;
    outline: none;
    background: transparent;
    transition: 0.3s;
}

.input-group label {
    position: absolute;
    top: 10px;
    left: 0;
    font-size: 16px;
    color: #999;
    pointer-events: none;
    transition: 0.3s;
}

.input-group input:focus ~ label,
.input-group input:valid ~ label {
    top: -20px;
    font-size: 12px;
    color: #1e3c72; /* Màu chữ khi focus phù hợp với màu nền */
}

.input-group input:focus {
    border-bottom: 2px solid #1e3c72;
}

.btn {
    width: 100%;
    padding: 12px;
    background-color: #1e3c72;
    color: white;
    border: none;
    border-radius: 25px; /* Bo tròn nút đăng nhập */
    cursor: pointer;
    font-size: 16px;
    font-weight: 500;
    transition: background-color 0.3s, transform 0.3s;
}

.btn:hover {
    background-color: #2a5298;
    transform: translateY(-2px);
}

.error {
    color: #f44336;
    text-align: center;
    margin-bottom: 20px;
    font-size: 14px;
    font-weight: 500;
}

@media (max-width: 480px) {
    .login-container {
        width: 90%;
        padding: 20px;
    }
}