body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    background-color: #f5f5f7;
}
.login-container {
    background-color: #ffffff;
    padding: 40px 50px;
    border-radius: 12px;
    box-shadow: 0 8px 30px rgba(0,0,0,0.12);
    text-align: center;
}
h1 {
    margin-bottom: 30px;
    color: #1d1d1f;
    font-size: 24px;
}
.return-button {
    display: block;
    width: 100%;
    padding: 12px;
    margin: 15px 0;
    background-color: #0078d4;
    border-color: #0078d4;
    border-radius: 8px;
    border: 1px solid transparent;
    font-size: 16px;
    font-weight: 500;
    text-decoration: none;
    color: #ffffff;
    cursor: pointer;
    transition: background-color 0.3s, box-shadow 0.3s;
}
.return-button:hover {
    background-color: #005a9e;
    box-shadow: 0 4px 10px rgba(0, 120, 212, 0.3);
}
.error-message {
    color: #d13438;
    font-size: 14px;
    margin-top: 20px;
}

.error-title {
    color: #d13438;
}

.success-title {
    color: #008000;
}

.error-details {
    margin-bottom: 30px;
    color: #333333;
    line-height: 1.5;
}

.success-details {
    margin-bottom: 30px;
    color: #333333;
    line-height: 1.5;
}

.instruction-text {
    color: #6c757d;
    font-size: 14px;
    margin-bottom: 25px;
    line-height: 1.5;
}

.error-banner {
    color: #d13438;
    font-size: 14px;
    margin-bottom: 25px;
    padding: 12px;
    background-color: #fdf2f2;
    border-radius: 8px;
    border: 1px solid #f5c2c7;
}

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

.form-group label, .form-group-last label {
    display: block;
    font-weight: 500;
    margin-bottom: 8px;
    color: #1d1d1f;
    font-size: 14px;
}

.form-control {
    width: 100%;
    padding: 12px;
    border: 1px solid #d2d2d7;
    border-radius: 8px;
    box-sizing: border-box;
    font-size: 16px;
    font-family: inherit;
    transition: border-color 0.3s, box-shadow 0.3s;
}

.form-control:focus {
    outline: none;
    border-color: #0078d4;
    box-shadow: 0 0 0 3px rgba(0, 120, 212, 0.2);
}

button.return-button {
    font-family: inherit;
    border: none;
}

/* --- Loading Spinner Styles --- */
.button-spinner {
    display: none; /* Hidden by default */
    width: 16px;
    height: 16px;
    margin-right: 8px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: #ffffff;
    animation: spin 1s ease-in-out infinite;
    vertical-align: middle;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* Make the button look inactive when disabled */
.return-button:disabled {
    background-color: #8bbdea;
    cursor: not-allowed;
    box-shadow: none;
}