body {
    font-family: Arial, sans-serif;
    background: #f5f5f5;
}

.login-box, .register-box {
    width: 350px;
    margin: 80px auto;
    background: #fff;
    padding: 30px 40px;
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.login-box h2, .register-box h2 {
    text-align: center;
    margin-bottom: 24px;
}

.form-group {
    margin-bottom: 18px;
}
.form-group label {
    display: block;
    margin-bottom: 6px;
}
.form-group input {
    width: 100%;
    padding: 8px;
    box-sizing: border-box;
}
.btn {
    width: 100%;
    padding: 10px;
    background: #007bff;
    color: #fff;
    border: none;
    border-radius: 4px;
    font-size: 16px;
    cursor: pointer;
}
.btn:hover {
    background: #0056b3;
}
.flash {
    color: #d9534f;
    text-align: center;
    margin-bottom: 10px;
}