body {
    font-family: Arial, sans-serif;
    background-color: #f0f2f5;
    margin: 0;
    padding: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
}

.container {
    max-width: 400px;
    width: 100%;
    padding: 30px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
    border-radius: 8px;
    background-color: #ffffff;
}

.title {
    text-align: center;
    color: #1877f2;
    margin-bottom: 24px;
    font-size: 24px;
}

.form-group {
    margin-bottom: 20px;
}

label {
    display: block;
    margin-bottom: 8px;
    color: #606770;
    font-weight: 500;
}

input[type="email"], input[type="password"] {
    width: 100%;
    padding: 12px;
    border: 1px solid #dddfe2;
    border-radius: 6px;
    font-size: 16px;
    transition: border-color 0.3s;
}

input[type="email"]:focus, input[type="password"]:focus {
    border-color: #1877f2;
    outline: none;
}

.submit-btn {
    width: 100%;
    padding: 12px;
    background-color: #1877f2;
    color: white;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-size: 18px;
    font-weight: bold;
    transition: background-color 0.3s;
    display: flex;
    align-items: center;
    justify-content: center;
}

.submit-btn:hover {
    background-color: #166fe5;
}

.submit-btn:disabled {
    cursor: not-allowed;
    opacity: 0.6;
}

.loading-spinner {
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top: 3px solid #ffffff;
    width: 16px;
    height: 16px;
    animation: spin 1s linear infinite;
    display: none;
    margin-left: 10px;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.error-message {
    color: #ff3b30;
    text-align: center;
    margin-bottom: 16px;
    font-size: 14px;
}

.register-link {
    text-align: center;
    margin-top: 20px;
    font-size: 14px;
    color: #606770;
}

.register-link a {
    color: #1877f2;
    text-decoration: none;
    font-weight: 500;
}

.register-link a:hover {
    text-decoration: underline;
}